from __future__ import annotations

from collections.abc import Iterable
from typing import Any

from fastapi import APIRouter, Depends, HTTPException, Query, status
from sqlalchemy.exc import IntegrityError
from sqlalchemy.orm import Session

from govoplan_access.backend.admin.governance import (
    assert_api_keys_allowed,
    assert_custom_groups_allowed,
    assert_custom_roles_allowed,
    ensure_group_mutation_allowed,
    ensure_role_mutation_allowed,
)
from govoplan_access.backend.admin.service import (
    AdminConflictError,
    AdminValidationError,
    assert_can_delegate_roles,
    assert_can_delegate_system_permissions,
    assert_can_delegate_system_roles,
    assert_can_delegate_tenant_permissions,
    assert_system_owner_exists,
    assert_tenant_owner_exists,
    create_custom_role,
    create_membership,
    create_system_role,
    delete_custom_role,
    delete_system_role,
    ensure_default_roles,
    get_or_create_account,
    set_group_members,
    set_group_roles,
    set_system_roles,
    set_user_groups,
    set_user_roles,
    slugify,
    tenant_owner_user_ids,
    update_custom_role,
    update_system_role,
)
from govoplan_access.backend.api.v1.admin_common import (
    _api_key_item,
    _group_summary,
    _http_admin_error,
    _require_permission,
    _require_system_role_assignment,
    _resolve_tenant,
    _role_summary,
    _set_system_memberships,
    _system_account_item,
    _user_item,
)
from govoplan_access.backend.api.v1.admin_schemas import (
    AdminApiKeyCreateRequest,
    AdminApiKeyCreateResponse,
    ApiKeyAdminItem,
    ApiKeyListDeltaResponse,
    ApiKeyListResponse,
    GroupCreateRequest,
    GroupListDeltaResponse,
    GroupListResponse,
    GroupSummary,
    GroupUpdateRequest,
    ExternalFunctionRoleMappingCreateRequest,
    ExternalFunctionRoleMappingItem,
    ExternalFunctionRoleMappingListDeltaResponse,
    ExternalFunctionRoleMappingListResponse,
    ExternalFunctionRoleMappingUpdateRequest,
    FunctionAdminItem,
    FunctionAssignmentAdminItem,
    FunctionAssignmentCreateRequest,
    FunctionAssignmentListResponse,
    FunctionAssignmentUpdateRequest,
    FunctionCreateRequest,
    FunctionDelegationAdminItem,
    FunctionDelegationCreateRequest,
    FunctionDelegationListResponse,
    FunctionDelegationUpdateRequest,
    FunctionListResponse,
    FunctionUpdateRequest,
    IdentityAdminItem,
    IdentityCreateRequest,
    IdentityListResponse,
    IdentityUpdateRequest,
    OrganizationUnitCreateRequest,
    OrganizationUnitItem,
    OrganizationUnitListResponse,
    OrganizationUnitUpdateRequest,
    ConfigurationChangeSafetyPlanRequest,
    ConfigurationChangeSafetyPlanResponse,
    ConfigurationChangeRequestApproveRequest,
    ConfigurationChangeRequestCreateRequest,
    ConfigurationChangeRequestResponse,
    ConfigurationControlDeltaResponse,
    ConfigurationControlSnapshotResponse,
    ConfigurationPackageApplyResponse,
    ConfigurationPackageCatalogResponse,
    ConfigurationPackageDryRunResponse,
    ConfigurationPackageExportRequest,
    ConfigurationPackageExportResponse,
    ConfigurationPackageRunRequest,
    ConfigurationSafetyCatalogResponse,
    ConfigurationSafetyFieldItem,
    PermissionCatalogResponse,
    PermissionItem,
    RoleCreateRequest,
    RoleListDeltaResponse,
    RoleListResponse,
    RoleSummary,
    RoleUpdateRequest,
    SystemAccountCreateRequest,
    SystemAccountCreateResponse,
    SystemAccountItem,
    SystemAccountListDeltaResponse,
    SystemAccountListResponse,
    SystemAccountMembershipsUpdateRequest,
    SystemAccountRolesUpdateRequest,
    SystemAccountUpdateRequest,
    UserCreateRequest,
    UserCreateResponse,
    UserAdminItem,
    UserListDeltaResponse,
    UserListResponse,
    UserUpdateRequest,
)
from govoplan_access.backend.security.api_keys import create_api_key
from govoplan_access.backend.security.sessions import collect_user_scopes
from govoplan_access.backend.auth.dependencies import ApiPrincipal, get_api_principal, has_scope, require_any_scope, require_scope
from govoplan_core.audit.logging import audit_event, audit_from_principal
from govoplan_access.backend.configuration_provider import ACCESS_CONFIGURATION_CAPABILITY, SqlAccessConfigurationProvider
from govoplan_access.backend.runtime import get_registry
from govoplan_core.core.configuration_packages import (
    CONFIGURATION_PROVIDER_CAPABILITY,
    ConfigurationExportSelection,
    ConfigurationPreflightContext,
    apply_configuration_package,
    dry_run_configuration_package,
    export_configuration_package,
    validate_configuration_package_catalog,
)
from govoplan_core.core.configuration_control import (
    CONFIGURATION_CHANGE_RECORD_RESOURCE,
    CONFIGURATION_CHANGE_REQUEST_RESOURCE,
    CONFIGURATION_CHANGES_COLLECTION,
    CONFIGURATION_CONTROL_MODULE_ID,
    ConfigurationControlError,
    approve_configuration_change_request,
    configuration_control_snapshot,
    create_configuration_change_request,
    ensure_configuration_change_allowed,
    record_configuration_change_applied,
)
from govoplan_core.core.configuration_safety import configuration_safety_catalog, plan_configuration_change
from govoplan_core.core.organizations import CAPABILITY_ORGANIZATION_DIRECTORY, ORGANIZATIONS_MODULE_ID, OrganizationDirectory
from govoplan_core.api.v1.schemas import DeltaDeletedItem
from govoplan_core.core.change_sequence import (
    decode_sequence_watermark,
    encode_sequence_watermark,
    max_sequence_id,
    record_change,
    sequence_entries_since,
    sequence_watermark_is_expired,
)
from govoplan_access.backend.db.models import (
    Account,
    ApiKey,
    ExternalFunctionRoleAssignment,
    Function,
    FunctionAssignment,
    FunctionDelegation,
    FunctionRoleAssignment,
    Group,
    GroupRoleAssignment,
    Identity,
    IdentityAccountLink,
    OrganizationUnit,
    Role,
    SystemRoleAssignment,
    Tenant,
    User,
    UserGroupMembership,
    UserRoleAssignment,
)
from govoplan_access.backend.semantic import identity_id_for_account
from govoplan_core.db.session import get_session
from govoplan_core.security.permissions import ALL_PERMISSIONS, normalize_email, scopes_grant
from govoplan_core.security.time import utc_now

router = APIRouter(prefix="/admin", tags=["admin"])

ACCESS_MODULE_ID = "access"
ACCESS_USERS_COLLECTION = "access.admin.users"
ACCESS_GROUPS_COLLECTION = "access.admin.groups"
ACCESS_ROLES_COLLECTION = "access.admin.roles"
ACCESS_IDENTITIES_COLLECTION = "access.admin.identities"
ACCESS_ORGANIZATION_UNITS_COLLECTION = "access.admin.organization_units"
ACCESS_FUNCTIONS_COLLECTION = "access.admin.functions"
ACCESS_EXTERNAL_FUNCTION_ROLE_MAPPINGS_COLLECTION = "access.admin.external_function_role_mappings"
ACCESS_FUNCTION_ASSIGNMENTS_COLLECTION = "access.admin.function_assignments"
ACCESS_FUNCTION_DELEGATIONS_COLLECTION = "access.admin.function_delegations"
ACCESS_SYSTEM_ROLES_COLLECTION = "access.admin.system_roles"
ACCESS_SYSTEM_ACCOUNTS_COLLECTION = "access.admin.system_accounts"
ACCESS_API_KEYS_COLLECTION = "access.admin.api_keys"


def _access_delta_watermark(session: Session, tenant_id: str | None, collections: tuple[str, ...]) -> str:
    return encode_sequence_watermark(
        max_sequence_id(
            session,
            tenant_id=tenant_id,
            module_id=ACCESS_MODULE_ID,
            collections=collections,
        )
    )


def _access_delta_entries(
    session: Session,
    *,
    tenant_id: str | None,
    collections: tuple[str, ...],
    since: str,
    limit: int,
):
    try:
        since_sequence = decode_sequence_watermark(since)
    except ValueError as exc:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
    if sequence_watermark_is_expired(
        session,
        since=since_sequence,
        tenant_id=tenant_id,
        module_id=ACCESS_MODULE_ID,
        collections=collections,
    ):
        return None, False
    entries_plus_one = sequence_entries_since(
        session,
        since=since_sequence,
        tenant_id=tenant_id,
        module_id=ACCESS_MODULE_ID,
        collections=collections,
        limit=limit + 1,
    )
    has_more = len(entries_plus_one) > limit
    return entries_plus_one[:limit], has_more


def _access_delta_response_watermark(
    session: Session,
    *,
    tenant_id: str | None,
    collections: tuple[str, ...],
    entries,
    has_more: bool,
) -> str:
    return (
        encode_sequence_watermark(entries[-1].id)
        if has_more and entries
        else _access_delta_watermark(session, tenant_id, collections)
    )


def _delta_deleted_item(entry) -> DeltaDeletedItem:
    return DeltaDeletedItem(
        id=entry.resource_id,
        resource_type=entry.resource_type,
        revision=encode_sequence_watermark(entry.id),
        deleted_at=entry.created_at if entry.operation == "deleted" else None,
    )


def _changed_ids(entries, resource_type: str) -> list[str]:
    return list(dict.fromkeys(entry.resource_id for entry in entries if entry.resource_type == resource_type))


def _record_access_change(
    session: Session,
    *,
    collection: str,
    resource_type: str,
    resource_id: str | None,
    operation: str,
    tenant_id: str | None,
    principal: ApiPrincipal,
    payload: dict | None = None,
) -> None:
    if not resource_id:
        return
    record_change(
        session,
        module_id=ACCESS_MODULE_ID,
        collection=collection,
        resource_type=resource_type,
        resource_id=resource_id,
        operation=operation,
        tenant_id=tenant_id,
        actor_type="user",
        actor_id=principal.user.id,
        payload=payload or {},
    )


def _require_any_permission(principal: ApiPrincipal, *scopes: str) -> None:
    if not any(has_scope(principal, scope) for scope in scopes):
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail=f"Requires one of: {', '.join(scopes)}")


def _identity_item(session: Session, identity: Identity) -> IdentityAdminItem:
    rows = (
        session.query(IdentityAccountLink, Account)
        .join(Account, Account.id == IdentityAccountLink.account_id)
        .filter(IdentityAccountLink.identity_id == identity.id)
        .order_by(IdentityAccountLink.is_primary.desc(), Account.email.asc())
        .all()
    )
    return IdentityAdminItem(
        id=identity.id,
        display_name=identity.display_name,
        external_subject=identity.external_subject,
        source=identity.source,
        is_active=identity.is_active,
        accounts=[
            {
                "id": link.id,
                "account_id": account.id,
                "email": account.email,
                "display_name": account.display_name,
                "is_primary": link.is_primary,
                "source": link.source,
            }
            for link, account in rows
        ],
        created_at=identity.created_at,
        updated_at=identity.updated_at,
    )


def _set_identity_accounts(
    session: Session,
    *,
    identity: Identity,
    account_ids: list[str],
    primary_account_id: str | None,
    source: str,
) -> None:
    requested = list(dict.fromkeys(account_ids))
    if primary_account_id and primary_account_id not in requested:
        requested.insert(0, primary_account_id)
    if not requested:
        session.query(IdentityAccountLink).filter(IdentityAccountLink.identity_id == identity.id).delete(synchronize_session=False)
        session.flush()
        return
    accounts = session.query(Account).filter(Account.id.in_(requested)).all()
    if len(accounts) != len(requested):
        raise AdminValidationError("One or more account IDs are unknown.")
    conflicting = (
        session.query(IdentityAccountLink)
        .filter(IdentityAccountLink.account_id.in_(requested), IdentityAccountLink.identity_id != identity.id)
        .first()
    )
    if conflicting is not None:
        raise AdminConflictError("One or more accounts are already linked to another identity.")
    primary = primary_account_id or requested[0]
    session.query(IdentityAccountLink).filter(IdentityAccountLink.identity_id == identity.id).delete(synchronize_session=False)
    for account_id in requested:
        session.add(
            IdentityAccountLink(
                identity_id=identity.id,
                account_id=account_id,
                is_primary=account_id == primary,
                source=source,
            )
        )
    session.flush()


def _organization_unit_item(item: OrganizationUnit) -> OrganizationUnitItem:
    return OrganizationUnitItem(
        id=item.id,
        tenant_id=item.tenant_id,
        parent_id=item.parent_id,
        slug=item.slug,
        name=item.name,
        description=item.description,
        is_active=item.is_active,
        created_at=item.created_at,
        updated_at=item.updated_at,
    )


def _validate_parent_organization_unit(
    session: Session,
    *,
    tenant_id: str,
    parent_id: str | None,
    current_id: str | None = None,
) -> None:
    if parent_id is None:
        return
    if parent_id == current_id:
        raise AdminValidationError("An organization unit cannot be its own parent.")
    parent = session.query(OrganizationUnit).filter(OrganizationUnit.id == parent_id, OrganizationUnit.tenant_id == tenant_id).one_or_none()
    if parent is None:
        raise AdminValidationError("Parent organization unit does not belong to the tenant.")


def _function_item(session: Session, item: Function) -> FunctionAdminItem:
    role_ids = [
        row[0]
        for row in session.query(FunctionRoleAssignment.role_id)
        .filter(FunctionRoleAssignment.function_id == item.id)
        .order_by(FunctionRoleAssignment.created_at.asc())
        .all()
    ]
    return FunctionAdminItem(
        id=item.id,
        tenant_id=item.tenant_id,
        organization_unit_id=item.organization_unit_id,
        slug=item.slug,
        name=item.name,
        description=item.description,
        role_ids=role_ids,
        delegable=item.delegable,
        act_in_place_allowed=item.act_in_place_allowed,
        is_active=item.is_active,
        created_at=item.created_at,
        updated_at=item.updated_at,
    )


def _set_function_roles(session: Session, *, function: Function, role_ids: list[str]) -> None:
    requested = sorted(set(role_ids))
    roles = (
        session.query(Role)
        .filter(Role.tenant_id == function.tenant_id, Role.id.in_(requested), Role.is_assignable.is_(True))
        .all()
        if requested else []
    )
    if len(roles) != len(requested):
        raise AdminValidationError("One or more selected roles are invalid or not assignable.")
    session.query(FunctionRoleAssignment).filter(FunctionRoleAssignment.function_id == function.id).delete(synchronize_session=False)
    for role in roles:
        session.add(FunctionRoleAssignment(tenant_id=function.tenant_id, function_id=function.id, role_id=role.id))
    session.flush()


def _external_function_role_mapping_item(item: ExternalFunctionRoleAssignment) -> ExternalFunctionRoleMappingItem:
    return ExternalFunctionRoleMappingItem(
        id=item.id,
        tenant_id=item.tenant_id,
        source_module=item.source_module,
        function_id=item.function_id,
        role_id=item.role_id,
        settings=item.settings or {},
        created_at=item.created_at,
        updated_at=item.updated_at,
    )


def _validate_external_function_role(
    session: Session,
    *,
    tenant_id: str,
    role_id: str,
) -> Role:
    role = session.query(Role).filter(Role.tenant_id == tenant_id, Role.id == role_id, Role.is_assignable.is_(True)).one_or_none()
    if role is None:
        raise AdminValidationError("Selected role is invalid or not assignable.")
    return role


def _organization_directory_or_error() -> OrganizationDirectory:
    registry = get_registry()
    if registry is None or not registry.has_capability(CAPABILITY_ORGANIZATION_DIRECTORY):
        raise HTTPException(
            status_code=status.HTTP_409_CONFLICT,
            detail={
                "code": "organizations_required",
                "message": "External function role mappings require the Organizations module.",
            },
        )
    capability = registry.require_capability(CAPABILITY_ORGANIZATION_DIRECTORY)
    if not isinstance(capability, OrganizationDirectory):
        raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=f"Invalid capability: {CAPABILITY_ORGANIZATION_DIRECTORY}")
    return capability


def _validate_external_function_source(*, tenant_id: str, source_module: str, function_id: str) -> None:
    if source_module != ORGANIZATIONS_MODULE_ID:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_CONTENT,
            detail=f"Unsupported function source module: {source_module}",
        )
    function = _organization_directory_or_error().get_function(function_id)
    if function is None or function.tenant_id != tenant_id:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Organization function not found.")
    if function.status != "active":
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Organization function is not active.")


def _function_assignment_item(item: FunctionAssignment) -> FunctionAssignmentAdminItem:
    return FunctionAssignmentAdminItem(
        id=item.id,
        tenant_id=item.tenant_id,
        account_id=item.account_id,
        identity_id=item.identity_id,
        function_id=item.function_id,
        organization_unit_id=item.organization_unit_id,
        applies_to_subunits=item.applies_to_subunits,
        source=item.source,
        delegated_from_assignment_id=item.delegated_from_assignment_id,
        acting_for_account_id=item.acting_for_account_id,
        valid_from=item.valid_from,
        valid_until=item.valid_until,
        is_active=item.is_active,
        created_at=item.created_at,
        updated_at=item.updated_at,
    )


def _validate_assignment_window(valid_from, valid_until) -> None:
    if valid_from is not None and valid_until is not None and valid_until <= valid_from:
        raise AdminValidationError("valid_until must be after valid_from.")


def _function_delegation_item(item: FunctionDelegation) -> FunctionDelegationAdminItem:
    return FunctionDelegationAdminItem(
        id=item.id,
        tenant_id=item.tenant_id,
        function_assignment_id=item.function_assignment_id,
        delegator_account_id=item.delegator_account_id,
        delegate_account_id=item.delegate_account_id,
        mode=item.mode,  # type: ignore[arg-type]
        reason=item.reason,
        valid_from=item.valid_from,
        valid_until=item.valid_until,
        revoked_at=item.revoked_at,
        is_active=item.is_active,
        created_at=item.created_at,
        updated_at=item.updated_at,
    )


def _record_many_access_changes(
    session: Session,
    *,
    collection: str,
    resource_type: str,
    resource_ids: Iterable[str],
    operation: str,
    tenant_id: str | None,
    principal: ApiPrincipal,
    payload: dict | None = None,
) -> None:
    for resource_id in sorted(set(resource_ids)):
        _record_access_change(
            session,
            collection=collection,
            resource_type=resource_type,
            resource_id=resource_id,
            operation=operation,
            tenant_id=tenant_id,
            principal=principal,
            payload=payload,
        )


def _current_user_group_ids(session: Session, user: User) -> set[str]:
    return {
        row[0]
        for row in session.query(UserGroupMembership.group_id)
        .filter(UserGroupMembership.tenant_id == user.tenant_id, UserGroupMembership.user_id == user.id)
        .all()
    }


def _current_user_role_ids(session: Session, user: User) -> set[str]:
    return {
        row[0]
        for row in session.query(UserRoleAssignment.role_id)
        .filter(UserRoleAssignment.tenant_id == user.tenant_id, UserRoleAssignment.user_id == user.id)
        .all()
    }


def _current_group_member_ids(session: Session, group: Group) -> set[str]:
    return {
        row[0]
        for row in session.query(UserGroupMembership.user_id)
        .filter(UserGroupMembership.tenant_id == group.tenant_id, UserGroupMembership.group_id == group.id)
        .all()
    }


def _current_group_role_ids(session: Session, group: Group) -> set[str]:
    return {
        row[0]
        for row in session.query(GroupRoleAssignment.role_id)
        .filter(GroupRoleAssignment.tenant_id == group.tenant_id, GroupRoleAssignment.group_id == group.id)
        .all()
    }


def _tenant_user_ids_for_role(session: Session, role_id: str, tenant_id: str) -> set[str]:
    direct = {
        row[0]
        for row in session.query(UserRoleAssignment.user_id)
        .filter(UserRoleAssignment.tenant_id == tenant_id, UserRoleAssignment.role_id == role_id)
        .all()
    }
    via_groups = {
        row[0]
        for row in session.query(UserGroupMembership.user_id)
        .join(GroupRoleAssignment, GroupRoleAssignment.group_id == UserGroupMembership.group_id)
        .filter(GroupRoleAssignment.tenant_id == tenant_id, GroupRoleAssignment.role_id == role_id)
        .all()
    }
    return direct | via_groups


def _tenant_group_ids_for_role(session: Session, role_id: str, tenant_id: str) -> set[str]:
    return {
        row[0]
        for row in session.query(GroupRoleAssignment.group_id)
        .filter(GroupRoleAssignment.tenant_id == tenant_id, GroupRoleAssignment.role_id == role_id)
        .all()
    }


def _system_account_ids_for_role(session: Session, role_id: str) -> set[str]:
    return {
        row[0]
        for row in session.query(SystemRoleAssignment.account_id)
        .filter(SystemRoleAssignment.role_id == role_id)
        .all()
    }


def _current_system_role_ids(session: Session, account: Account) -> set[str]:
    return {
        row[0]
        for row in session.query(SystemRoleAssignment.role_id)
        .filter(SystemRoleAssignment.account_id == account.id)
        .all()
    }


@router.get("/permissions", response_model=PermissionCatalogResponse)
def permission_catalog(
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:read", "system:roles:read", "system:access:read", "system:governance:read")),
):
    items = [
        PermissionItem(
            scope=item.scope,
            label=item.label,
            description=item.description,
            category=item.category,
            level=item.level,
        )
        for item in ALL_PERMISSIONS
        if item.level == "tenant" or has_scope(principal, "system:roles:read") or has_scope(principal, "system:access:read") or has_scope(principal, "system:governance:read")
    ]
    return PermissionCatalogResponse(permissions=items)


@router.get("/configuration-safety", response_model=ConfigurationSafetyCatalogResponse)
def configuration_safety_catalog_endpoint(
    include_env_only: bool = False,
    principal: ApiPrincipal = Depends(require_any_scope("admin:settings:read", "admin:policies:read", "system:settings:read", "system:governance:read")),
):
    del principal
    return ConfigurationSafetyCatalogResponse(fields=[ConfigurationSafetyFieldItem(**item.to_dict()) for item in configuration_safety_catalog(include_env_only=include_env_only)])


@router.post("/configuration-safety/plan", response_model=ConfigurationChangeSafetyPlanResponse)
def configuration_change_safety_plan(
    payload: ConfigurationChangeSafetyPlanRequest,
    principal: ApiPrincipal = Depends(require_any_scope("admin:settings:read", "admin:policies:read", "system:settings:read", "system:governance:read")),
):
    plan = plan_configuration_change(
        payload.key,
        actor_scopes=tuple(principal.scopes),
        value=payload.value,
        dry_run=payload.dry_run,
        maintenance_mode=payload.maintenance_mode,
        approval_count=payload.approval_count,
        include_env_only=True,
    )
    return ConfigurationChangeSafetyPlanResponse(plan=plan.to_dict())


@router.get("/configuration-packages/catalog", response_model=ConfigurationPackageCatalogResponse)
def configuration_package_catalog_validation(
    principal: ApiPrincipal = Depends(require_any_scope("admin:settings:read", "system:settings:read", "system:governance:read")),
):
    del principal
    return ConfigurationPackageCatalogResponse(validation=validate_configuration_package_catalog())


@router.post("/configuration-packages/dry-run", response_model=ConfigurationPackageDryRunResponse)
def configuration_package_dry_run_endpoint(
    payload: ConfigurationPackageRunRequest,
    principal: ApiPrincipal = Depends(require_any_scope("admin:settings:read", "admin:policies:read", "system:settings:read", "system:governance:read")),
):
    result = dry_run_configuration_package(payload.package, _configuration_providers(), _configuration_context(principal, tenant_id=payload.tenant_id, supplied_data=payload.supplied_data))
    return ConfigurationPackageDryRunResponse(
        diagnostics=[item.to_dict() for item in result.diagnostics],
        required_data=[item.to_dict() for item in result.required_data],
        plan=[item.to_dict() for item in result.plan],
    )


@router.post("/configuration-packages/apply", response_model=ConfigurationPackageApplyResponse)
def configuration_package_apply_endpoint(
    payload: ConfigurationPackageRunRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:settings:write", "admin:policies:write", "system:settings:write", "system:governance:write")),
):
    try:
        approval = ensure_configuration_change_allowed(
            session,
            key="configuration_packages.apply",
            value=payload.package,
            actor_user_id=principal.user.id,
            actor_scopes=tuple(principal.scopes),
            change_request_id=payload.change_request_id,
            target={"tenant_id": payload.tenant_id or principal.tenant_id},
        )
    except ConfigurationControlError as exc:
        raise _configuration_control_http_error(exc) from exc
    result = apply_configuration_package(payload.package, _configuration_providers(), _configuration_context(principal, tenant_id=payload.tenant_id, supplied_data=payload.supplied_data))
    record_configuration_change_applied(
        session,
        key="configuration_packages.apply",
        before_value={},
        after_value=payload.package,
        actor_user_id=principal.user.id,
        approval=approval,
        target={"tenant_id": payload.tenant_id or principal.tenant_id},
        audit_event="configuration_package.applied",
    )
    audit_from_principal(
        session,
        principal,
        action="configuration_package.applied",
        scope="system",
        object_type="configuration_package",
        object_id=approval.request.get("id") if approval.request else "direct",
        details={"tenant_id": payload.tenant_id or principal.tenant_id},
    )
    session.commit()
    return ConfigurationPackageApplyResponse(
        diagnostics=[item.to_dict() for item in result.diagnostics],
        created_refs=dict(result.created_refs),
        updated_refs=dict(result.updated_refs),
    )


@router.post("/configuration-packages/export", response_model=ConfigurationPackageExportResponse)
def configuration_package_export_endpoint(
    payload: ConfigurationPackageExportRequest,
    principal: ApiPrincipal = Depends(require_any_scope("admin:settings:read", "admin:policies:read", "system:settings:read", "system:governance:read")),
):
    selection = ConfigurationExportSelection(
        tenant_id=payload.tenant_id,
        scopes=tuple(payload.scopes),
        module_ids=tuple(payload.module_ids),
        object_refs=tuple(payload.object_refs),
    )
    result = export_configuration_package(_configuration_providers(), selection, _configuration_context(principal, tenant_id=payload.tenant_id))
    return ConfigurationPackageExportResponse(
        fragments=[item.to_dict() for item in result.fragments],
        data_requirements=[item.to_dict() for item in result.data_requirements],
        diagnostics=[item.to_dict() for item in result.diagnostics],
    )


def _configuration_providers() -> tuple[object, ...]:
    registry = get_registry()
    if registry is not None and hasattr(registry, "has_capability") and registry.has_capability(ACCESS_CONFIGURATION_CAPABILITY):
        capability = registry.capability(ACCESS_CONFIGURATION_CAPABILITY)
        if capability is not None:
            return (capability,)
    return (SqlAccessConfigurationProvider(),)


def _configuration_context(principal: ApiPrincipal, *, tenant_id: str | None = None, supplied_data: dict[str, Any] | None = None) -> ConfigurationPreflightContext:
    registry = get_registry()
    installed_modules: dict[str, str] = {"access": "0.1.6"}
    capabilities = {CONFIGURATION_PROVIDER_CAPABILITY, ACCESS_CONFIGURATION_CAPABILITY}
    if registry is not None and hasattr(registry, "manifests"):
        manifests = registry.manifests()
        installed_modules = {manifest.id: manifest.version for manifest in manifests}
        if hasattr(registry, "has_capability") and registry.has_capability(ACCESS_CONFIGURATION_CAPABILITY):
            capabilities.add(ACCESS_CONFIGURATION_CAPABILITY)
    return ConfigurationPreflightContext(
        tenant_id=tenant_id or principal.tenant_id,
        operator_user_id=principal.user.id,
        supplied_data=supplied_data or {},
        installed_modules=installed_modules,
        capabilities=frozenset(capabilities),
    )


def _configuration_control_http_error(exc: ConfigurationControlError) -> HTTPException:
    return HTTPException(
        status_code=status.HTTP_409_CONFLICT,
        detail={"code": exc.code, "message": str(exc), "plan": exc.plan},
    )


def _configuration_delta_watermark(session: Session) -> str:
    return encode_sequence_watermark(
        max_sequence_id(
            session,
            module_id=CONFIGURATION_CONTROL_MODULE_ID,
            collections=(CONFIGURATION_CHANGES_COLLECTION,),
        )
    )


def _configuration_delta_entries(session: Session, *, since: str, limit: int):
    try:
        since_sequence = decode_sequence_watermark(since)
    except ValueError as exc:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
    if sequence_watermark_is_expired(
        session,
        since=since_sequence,
        module_id=CONFIGURATION_CONTROL_MODULE_ID,
        collections=(CONFIGURATION_CHANGES_COLLECTION,),
    ):
        return None, False
    entries_plus_one = sequence_entries_since(
        session,
        since=since_sequence,
        module_id=CONFIGURATION_CONTROL_MODULE_ID,
        collections=(CONFIGURATION_CHANGES_COLLECTION,),
        limit=limit + 1,
    )
    has_more = len(entries_plus_one) > limit
    return entries_plus_one[:limit], has_more


def _configuration_delta_response_watermark(session: Session, *, entries, has_more: bool) -> str:
    return encode_sequence_watermark(entries[-1].id) if has_more and entries else _configuration_delta_watermark(session)


def _full_configuration_delta_response(session: Session) -> ConfigurationControlDeltaResponse:
    snapshot = configuration_control_snapshot(session)
    return ConfigurationControlDeltaResponse(
        requests=snapshot["requests"],
        history=snapshot["history"],
        deleted=[],
        watermark=_configuration_delta_watermark(session),
        has_more=False,
        full=True,
    )


@router.get("/configuration-changes", response_model=ConfigurationControlSnapshotResponse)
def list_configuration_changes(
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:settings:read", "admin:policies:read", "system:settings:read", "system:governance:read")),
):
    del principal
    return ConfigurationControlSnapshotResponse(**configuration_control_snapshot(session))


@router.get("/configuration-changes/delta", response_model=ConfigurationControlDeltaResponse)
def list_configuration_changes_delta(
    since: str | None = None,
    limit: int = Query(default=100, ge=1, le=500),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:settings:read", "admin:policies:read", "system:settings:read", "system:governance:read")),
):
    del principal
    if since is None:
        return _full_configuration_delta_response(session)
    entries, has_more = _configuration_delta_entries(session, since=since, limit=limit)
    if entries is None:
        return _full_configuration_delta_response(session)
    request_ids = {
        entry.resource_id
        for entry in entries
        if entry.resource_type == CONFIGURATION_CHANGE_REQUEST_RESOURCE
    }
    record_ids = {
        entry.resource_id
        for entry in entries
        if entry.resource_type == CONFIGURATION_CHANGE_RECORD_RESOURCE
    }
    snapshot = configuration_control_snapshot(session)
    return ConfigurationControlDeltaResponse(
        requests=[item for item in snapshot["requests"] if item.get("id") in request_ids],
        history=[item for item in snapshot["history"] if item.get("id") in record_ids],
        deleted=[],
        watermark=_configuration_delta_response_watermark(session, entries=entries, has_more=has_more),
        has_more=has_more,
        full=False,
    )


@router.post("/configuration-change-requests", response_model=ConfigurationChangeRequestResponse, status_code=status.HTTP_201_CREATED)
def create_configuration_change_request_endpoint(
    payload: ConfigurationChangeRequestCreateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:settings:write", "admin:policies:write", "system:settings:write", "system:governance:write")),
):
    try:
        request = create_configuration_change_request(
            session,
            key=payload.key,
            value=payload.value,
            actor_user_id=principal.user.id,
            actor_scopes=tuple(principal.scopes),
            dry_run=payload.dry_run,
            target=payload.target,
            reason=payload.reason,
        )
    except ConfigurationControlError as exc:
        raise _configuration_control_http_error(exc) from exc
    audit_from_principal(
        session,
        principal,
        action="configuration_change.requested",
        scope="system",
        object_type="configuration_change_request",
        object_id=str(request["id"]),
        details={"key": payload.key, "target": payload.target, "dry_run": payload.dry_run},
    )
    session.commit()
    return ConfigurationChangeRequestResponse(request=request)


@router.post("/configuration-change-requests/{request_id}/approve", response_model=ConfigurationChangeRequestResponse)
def approve_configuration_change_request_endpoint(
    request_id: str,
    payload: ConfigurationChangeRequestApproveRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:settings:write", "admin:policies:write", "system:settings:write", "system:governance:write")),
):
    try:
        request = approve_configuration_change_request(
            session,
            request_id=request_id,
            actor_user_id=principal.user.id,
            actor_scopes=tuple(principal.scopes),
            reason=payload.reason,
        )
    except ConfigurationControlError as exc:
        raise _configuration_control_http_error(exc) from exc
    audit_from_principal(
        session,
        principal,
        action="configuration_change.approved",
        scope="system",
        object_type="configuration_change_request",
        object_id=request_id,
        details={"key": request.get("key")},
    )
    session.commit()
    return ConfigurationChangeRequestResponse(request=request)


@router.get("/identities", response_model=IdentityListResponse)
def list_identities(
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("system:accounts:read", "access:account:read")),
):
    del principal
    identities = session.query(Identity).order_by(Identity.display_name.asc(), Identity.created_at.asc()).all()
    return IdentityListResponse(identities=[_identity_item(session, item) for item in identities])


@router.post("/identities", response_model=IdentityAdminItem, status_code=status.HTTP_201_CREATED)
def create_identity(
    payload: IdentityCreateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("system:accounts:update", "access:account:update")),
):
    identity = Identity(
        display_name=payload.display_name.strip() if payload.display_name else None,
        external_subject=payload.external_subject.strip() if payload.external_subject else None,
        source=payload.source.strip() or "local",
        is_active=payload.is_active,
    )
    session.add(identity)
    session.flush()
    try:
        _set_identity_accounts(
            session,
            identity=identity,
            account_ids=payload.account_ids,
            primary_account_id=payload.primary_account_id,
            source=identity.source,
        )
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_IDENTITIES_COLLECTION,
        resource_type="access_identity",
        resource_id=identity.id,
        operation="created",
        tenant_id=None,
        principal=principal,
    )
    session.commit()
    return _identity_item(session, identity)


@router.patch("/identities/{identity_id}", response_model=IdentityAdminItem)
def update_identity(
    identity_id: str,
    payload: IdentityUpdateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("system:accounts:update", "access:account:update")),
):
    identity = session.get(Identity, identity_id)
    if identity is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Identity not found")
    if payload.display_name is not None:
        identity.display_name = payload.display_name.strip() or None
    if payload.external_subject is not None:
        identity.external_subject = payload.external_subject.strip() or None
    if payload.source is not None:
        identity.source = payload.source.strip() or "local"
    if payload.is_active is not None:
        identity.is_active = payload.is_active
    session.add(identity)
    session.flush()
    if payload.account_ids is not None or payload.primary_account_id is not None:
        existing = [
            row[0]
            for row in session.query(IdentityAccountLink.account_id)
            .filter(IdentityAccountLink.identity_id == identity.id)
            .all()
        ]
        try:
            _set_identity_accounts(
                session,
                identity=identity,
                account_ids=payload.account_ids if payload.account_ids is not None else existing,
                primary_account_id=payload.primary_account_id,
                source=identity.source,
            )
        except (AdminConflictError, AdminValidationError) as exc:
            raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_IDENTITIES_COLLECTION,
        resource_type="access_identity",
        resource_id=identity.id,
        operation="updated",
        tenant_id=None,
        principal=principal,
    )
    session.commit()
    return _identity_item(session, identity)


@router.delete("/identities/{identity_id}", status_code=status.HTTP_204_NO_CONTENT)
def deactivate_identity(
    identity_id: str,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("system:accounts:update", "access:account:update")),
):
    identity = session.get(Identity, identity_id)
    if identity is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Identity not found")
    identity.is_active = False
    session.add(identity)
    _record_access_change(
        session,
        collection=ACCESS_IDENTITIES_COLLECTION,
        resource_type="access_identity",
        resource_id=identity.id,
        operation="deleted",
        tenant_id=None,
        principal=principal,
    )
    session.commit()
    return None


@router.get("/organization-units", response_model=OrganizationUnitListResponse)
def list_organization_units(
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:read", "access:function:read", "access:role:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    items = (
        session.query(OrganizationUnit)
        .filter(OrganizationUnit.tenant_id == tenant.id)
        .order_by(OrganizationUnit.name.asc())
        .all()
    )
    return OrganizationUnitListResponse(organization_units=[_organization_unit_item(item) for item in items])


@router.post("/organization-units", response_model=OrganizationUnitItem, status_code=status.HTTP_201_CREATED)
def create_organization_unit(
    payload: OrganizationUnitCreateRequest,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:write", "access:function:write")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    slug = slugify(payload.slug)
    if not slug:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Enter a slug.")
    if session.query(OrganizationUnit).filter(OrganizationUnit.tenant_id == tenant.id, OrganizationUnit.slug == slug).count():
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="An organization unit with this slug already exists.")
    try:
        _validate_parent_organization_unit(session, tenant_id=tenant.id, parent_id=payload.parent_id)
    except AdminValidationError as exc:
        raise _http_admin_error(exc) from exc
    item = OrganizationUnit(
        tenant_id=tenant.id,
        parent_id=payload.parent_id,
        slug=slug,
        name=payload.name.strip(),
        description=payload.description.strip() if payload.description else None,
        is_active=payload.is_active,
    )
    session.add(item)
    session.flush()
    _record_access_change(
        session,
        collection=ACCESS_ORGANIZATION_UNITS_COLLECTION,
        resource_type="access_organization_unit",
        resource_id=item.id,
        operation="created",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return _organization_unit_item(item)


@router.patch("/organization-units/{organization_unit_id}", response_model=OrganizationUnitItem)
def update_organization_unit(
    organization_unit_id: str,
    payload: OrganizationUnitUpdateRequest,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:write", "access:function:write")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    item = session.query(OrganizationUnit).filter(OrganizationUnit.id == organization_unit_id, OrganizationUnit.tenant_id == tenant.id).one_or_none()
    if item is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Organization unit not found")
    if payload.slug is not None:
        slug = slugify(payload.slug)
        if not slug:
            raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Enter a slug.")
        if session.query(OrganizationUnit).filter(OrganizationUnit.tenant_id == tenant.id, OrganizationUnit.slug == slug, OrganizationUnit.id != item.id).count():
            raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="An organization unit with this slug already exists.")
        item.slug = slug
    if payload.parent_id is not None:
        try:
            _validate_parent_organization_unit(session, tenant_id=tenant.id, parent_id=payload.parent_id, current_id=item.id)
        except AdminValidationError as exc:
            raise _http_admin_error(exc) from exc
        item.parent_id = payload.parent_id
    if payload.name is not None:
        item.name = payload.name.strip()
    if payload.description is not None:
        item.description = payload.description.strip() or None
    if payload.is_active is not None:
        item.is_active = payload.is_active
    session.add(item)
    _record_access_change(
        session,
        collection=ACCESS_ORGANIZATION_UNITS_COLLECTION,
        resource_type="access_organization_unit",
        resource_id=item.id,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return _organization_unit_item(item)


@router.delete("/organization-units/{organization_unit_id}", status_code=status.HTTP_204_NO_CONTENT)
def deactivate_organization_unit(
    organization_unit_id: str,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:write", "access:function:write")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    item = session.query(OrganizationUnit).filter(OrganizationUnit.id == organization_unit_id, OrganizationUnit.tenant_id == tenant.id).one_or_none()
    if item is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Organization unit not found")
    item.is_active = False
    session.add(item)
    _record_access_change(
        session,
        collection=ACCESS_ORGANIZATION_UNITS_COLLECTION,
        resource_type="access_organization_unit",
        resource_id=item.id,
        operation="deleted",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return None


@router.get("/functions", response_model=FunctionListResponse)
def list_functions(
    tenant_id: str | None = None,
    organization_unit_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:read", "access:function:read", "access:role:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    query = session.query(Function).filter(Function.tenant_id == tenant.id)
    if organization_unit_id:
        query = query.filter(Function.organization_unit_id == organization_unit_id)
    functions = query.order_by(Function.name.asc()).all()
    return FunctionListResponse(functions=[_function_item(session, item) for item in functions])


@router.post("/functions", response_model=FunctionAdminItem, status_code=status.HTTP_201_CREATED)
def create_function(
    payload: FunctionCreateRequest,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:write", "access:function:write")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    unit = session.query(OrganizationUnit).filter(OrganizationUnit.id == payload.organization_unit_id, OrganizationUnit.tenant_id == tenant.id).one_or_none()
    if unit is None:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Organization unit not found")
    slug = slugify(payload.slug)
    if not slug:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Enter a slug.")
    if session.query(Function).filter(Function.tenant_id == tenant.id, Function.organization_unit_id == unit.id, Function.slug == slug).count():
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="A function with this slug already exists in the organization unit.")
    function = Function(
        tenant_id=tenant.id,
        organization_unit_id=unit.id,
        slug=slug,
        name=payload.name.strip(),
        description=payload.description.strip() if payload.description else None,
        delegable=payload.delegable,
        act_in_place_allowed=payload.act_in_place_allowed,
        is_active=payload.is_active,
    )
    session.add(function)
    session.flush()
    try:
        _set_function_roles(session, function=function, role_ids=payload.role_ids)
    except AdminValidationError as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_FUNCTIONS_COLLECTION,
        resource_type="access_function",
        resource_id=function.id,
        operation="created",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return _function_item(session, function)


@router.patch("/functions/{function_id}", response_model=FunctionAdminItem)
def update_function(
    function_id: str,
    payload: FunctionUpdateRequest,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:write", "access:function:write")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    function = session.query(Function).filter(Function.id == function_id, Function.tenant_id == tenant.id).one_or_none()
    if function is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Function not found")
    if payload.organization_unit_id is not None:
        unit = session.query(OrganizationUnit).filter(OrganizationUnit.id == payload.organization_unit_id, OrganizationUnit.tenant_id == tenant.id).one_or_none()
        if unit is None:
            raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Organization unit not found")
        function.organization_unit_id = unit.id
    if payload.slug is not None:
        slug = slugify(payload.slug)
        if not slug:
            raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Enter a slug.")
        if session.query(Function).filter(Function.tenant_id == tenant.id, Function.organization_unit_id == function.organization_unit_id, Function.slug == slug, Function.id != function.id).count():
            raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="A function with this slug already exists in the organization unit.")
        function.slug = slug
    if payload.name is not None:
        function.name = payload.name.strip()
    if payload.description is not None:
        function.description = payload.description.strip() or None
    if payload.delegable is not None:
        function.delegable = payload.delegable
    if payload.act_in_place_allowed is not None:
        function.act_in_place_allowed = payload.act_in_place_allowed
    if payload.is_active is not None:
        function.is_active = payload.is_active
    session.add(function)
    session.flush()
    if payload.role_ids is not None:
        try:
            _set_function_roles(session, function=function, role_ids=payload.role_ids)
        except AdminValidationError as exc:
            raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_FUNCTIONS_COLLECTION,
        resource_type="access_function",
        resource_id=function.id,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return _function_item(session, function)


@router.delete("/functions/{function_id}", status_code=status.HTTP_204_NO_CONTENT)
def deactivate_function(
    function_id: str,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:write", "access:function:write")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    function = session.query(Function).filter(Function.id == function_id, Function.tenant_id == tenant.id).one_or_none()
    if function is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Function not found")
    function.is_active = False
    session.add(function)
    _record_access_change(
        session,
        collection=ACCESS_FUNCTIONS_COLLECTION,
        resource_type="access_function",
        resource_id=function.id,
        operation="deleted",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return None


@router.get("/external-function-role-mappings", response_model=ExternalFunctionRoleMappingListResponse)
def list_external_function_role_mappings(
    tenant_id: str | None = None,
    source_module: str | None = None,
    function_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:read", "access:function:read", "access:role:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    query = session.query(ExternalFunctionRoleAssignment).filter(ExternalFunctionRoleAssignment.tenant_id == tenant.id)
    if source_module:
        query = query.filter(ExternalFunctionRoleAssignment.source_module == source_module.strip())
    if function_id:
        query = query.filter(ExternalFunctionRoleAssignment.function_id == function_id.strip())
    items = query.order_by(ExternalFunctionRoleAssignment.source_module.asc(), ExternalFunctionRoleAssignment.function_id.asc()).all()
    return ExternalFunctionRoleMappingListResponse(mappings=[_external_function_role_mapping_item(item) for item in items])


def _full_external_function_role_mappings_delta_response(session: Session, tenant: Tenant) -> ExternalFunctionRoleMappingListDeltaResponse:
    items = (
        session.query(ExternalFunctionRoleAssignment)
        .filter(ExternalFunctionRoleAssignment.tenant_id == tenant.id)
        .order_by(ExternalFunctionRoleAssignment.source_module.asc(), ExternalFunctionRoleAssignment.function_id.asc())
        .all()
    )
    return ExternalFunctionRoleMappingListDeltaResponse(
        mappings=[_external_function_role_mapping_item(item) for item in items],
        deleted=[],
        watermark=_access_delta_watermark(session, tenant.id, (ACCESS_EXTERNAL_FUNCTION_ROLE_MAPPINGS_COLLECTION,)),
        has_more=False,
        full=True,
    )


def _external_function_role_mappings_delta_response(
    session: Session,
    tenant: Tenant,
    *,
    since: str,
    limit: int,
) -> ExternalFunctionRoleMappingListDeltaResponse:
    entries, has_more = _access_delta_entries(
        session,
        tenant_id=tenant.id,
        collections=(ACCESS_EXTERNAL_FUNCTION_ROLE_MAPPINGS_COLLECTION,),
        since=since,
        limit=limit,
    )
    if entries is None:
        return _full_external_function_role_mappings_delta_response(session, tenant)
    changed_ids = _changed_ids(entries, "access_external_function_role_mapping")
    visible = {
        item.id: item
        for item in (
            session.query(ExternalFunctionRoleAssignment)
            .filter(ExternalFunctionRoleAssignment.tenant_id == tenant.id, ExternalFunctionRoleAssignment.id.in_(changed_ids))
            .all()
            if changed_ids
            else []
        )
    }
    deleted = [
        _delta_deleted_item(entry)
        for entry in entries
        if entry.resource_type == "access_external_function_role_mapping" and entry.resource_id not in visible
    ]
    return ExternalFunctionRoleMappingListDeltaResponse(
        mappings=[_external_function_role_mapping_item(item) for item in visible.values()],
        deleted=deleted,
        watermark=_access_delta_response_watermark(
            session,
            tenant_id=tenant.id,
            collections=(ACCESS_EXTERNAL_FUNCTION_ROLE_MAPPINGS_COLLECTION,),
            entries=entries,
            has_more=has_more,
        ),
        has_more=has_more,
        full=False,
    )


@router.get("/external-function-role-mappings/delta", response_model=ExternalFunctionRoleMappingListDeltaResponse)
def list_external_function_role_mappings_delta(
    tenant_id: str | None = Query(default=None),
    since: str | None = None,
    limit: int = Query(default=500, ge=1, le=1000),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:read", "access:function:read", "access:role:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    if since is None:
        return _full_external_function_role_mappings_delta_response(session, tenant)
    return _external_function_role_mappings_delta_response(session, tenant, since=since, limit=limit)


@router.post("/external-function-role-mappings", response_model=ExternalFunctionRoleMappingItem, status_code=status.HTTP_201_CREATED)
def create_external_function_role_mapping(
    payload: ExternalFunctionRoleMappingCreateRequest,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:write", "access:function:write", "access:role:assign")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    source_module = payload.source_module.strip() or ORGANIZATIONS_MODULE_ID
    function_id = payload.function_id.strip()
    if not function_id:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Function ID is required.")
    _validate_external_function_source(tenant_id=tenant.id, source_module=source_module, function_id=function_id)
    _validate_external_function_role(session, tenant_id=tenant.id, role_id=payload.role_id)
    item = ExternalFunctionRoleAssignment(
        tenant_id=tenant.id,
        source_module=source_module,
        function_id=function_id,
        role_id=payload.role_id,
        settings=payload.settings,
    )
    session.add(item)
    try:
        session.flush()
    except IntegrityError as exc:
        session.rollback()
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="This external function role mapping already exists.") from exc
    _record_access_change(
        session,
        collection=ACCESS_EXTERNAL_FUNCTION_ROLE_MAPPINGS_COLLECTION,
        resource_type="access_external_function_role_mapping",
        resource_id=item.id,
        operation="created",
        tenant_id=tenant.id,
        principal=principal,
        payload={"source_module": source_module, "function_id": function_id, "role_id": payload.role_id},
    )
    session.commit()
    return _external_function_role_mapping_item(item)


@router.patch("/external-function-role-mappings/{mapping_id}", response_model=ExternalFunctionRoleMappingItem)
def update_external_function_role_mapping(
    mapping_id: str,
    payload: ExternalFunctionRoleMappingUpdateRequest,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:write", "access:function:write", "access:role:assign")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    item = session.query(ExternalFunctionRoleAssignment).filter(ExternalFunctionRoleAssignment.id == mapping_id, ExternalFunctionRoleAssignment.tenant_id == tenant.id).one_or_none()
    if item is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="External function role mapping not found")
    _validate_external_function_source(tenant_id=tenant.id, source_module=item.source_module, function_id=item.function_id)
    if payload.role_id is not None:
        _validate_external_function_role(session, tenant_id=tenant.id, role_id=payload.role_id)
        item.role_id = payload.role_id
    if payload.settings is not None:
        item.settings = payload.settings
    session.add(item)
    try:
        session.flush()
    except IntegrityError as exc:
        session.rollback()
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="This external function role mapping already exists.") from exc
    _record_access_change(
        session,
        collection=ACCESS_EXTERNAL_FUNCTION_ROLE_MAPPINGS_COLLECTION,
        resource_type="access_external_function_role_mapping",
        resource_id=item.id,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
        payload={"source_module": item.source_module, "function_id": item.function_id, "role_id": item.role_id},
    )
    session.commit()
    return _external_function_role_mapping_item(item)


@router.delete("/external-function-role-mappings/{mapping_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_external_function_role_mapping(
    mapping_id: str,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:write", "access:function:write", "access:role:assign")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    item = session.query(ExternalFunctionRoleAssignment).filter(ExternalFunctionRoleAssignment.id == mapping_id, ExternalFunctionRoleAssignment.tenant_id == tenant.id).one_or_none()
    if item is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="External function role mapping not found")
    session.delete(item)
    _record_access_change(
        session,
        collection=ACCESS_EXTERNAL_FUNCTION_ROLE_MAPPINGS_COLLECTION,
        resource_type="access_external_function_role_mapping",
        resource_id=mapping_id,
        operation="deleted",
        tenant_id=tenant.id,
        principal=principal,
        payload={"source_module": item.source_module, "function_id": item.function_id, "role_id": item.role_id},
    )
    session.commit()
    return None


@router.get("/function-assignments", response_model=FunctionAssignmentListResponse)
def list_function_assignments(
    tenant_id: str | None = None,
    account_id: str | None = None,
    function_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:read", "access:function:read", "access:function:assign")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    query = session.query(FunctionAssignment).filter(FunctionAssignment.tenant_id == tenant.id)
    if account_id:
        query = query.filter(FunctionAssignment.account_id == account_id)
    if function_id:
        query = query.filter(FunctionAssignment.function_id == function_id)
    assignments = query.order_by(FunctionAssignment.created_at.desc()).all()
    return FunctionAssignmentListResponse(assignments=[_function_assignment_item(item) for item in assignments])


@router.post("/function-assignments", response_model=FunctionAssignmentAdminItem, status_code=status.HTTP_201_CREATED)
def create_function_assignment(
    payload: FunctionAssignmentCreateRequest,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:assign", "access:function:assign")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    account = session.get(Account, payload.account_id)
    if account is None:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Account not found")
    function = session.query(Function).filter(Function.id == payload.function_id, Function.tenant_id == tenant.id).one_or_none()
    if function is None:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Function not found")
    organization_unit_id = payload.organization_unit_id or function.organization_unit_id
    unit = session.query(OrganizationUnit).filter(OrganizationUnit.id == organization_unit_id, OrganizationUnit.tenant_id == tenant.id).one_or_none()
    if unit is None:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Organization unit not found")
    identity_id = payload.identity_id or identity_id_for_account(session, account.id)
    if identity_id is not None and session.get(Identity, identity_id) is None:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Identity not found")
    try:
        _validate_assignment_window(payload.valid_from, payload.valid_until)
    except AdminValidationError as exc:
        raise _http_admin_error(exc) from exc
    assignment = FunctionAssignment(
        tenant_id=tenant.id,
        account_id=account.id,
        identity_id=identity_id,
        function_id=function.id,
        organization_unit_id=unit.id,
        applies_to_subunits=payload.applies_to_subunits,
        source=payload.source.strip() or "direct",
        delegated_from_assignment_id=payload.delegated_from_assignment_id,
        acting_for_account_id=payload.acting_for_account_id,
        valid_from=payload.valid_from,
        valid_until=payload.valid_until,
        is_active=payload.is_active,
    )
    session.add(assignment)
    try:
        session.flush()
    except IntegrityError as exc:
        raise _http_admin_error(AdminConflictError("This function assignment already exists for the account and scope.")) from exc
    _record_access_change(
        session,
        collection=ACCESS_FUNCTION_ASSIGNMENTS_COLLECTION,
        resource_type="access_function_assignment",
        resource_id=assignment.id,
        operation="created",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return _function_assignment_item(assignment)


@router.patch("/function-assignments/{assignment_id}", response_model=FunctionAssignmentAdminItem)
def update_function_assignment(
    assignment_id: str,
    payload: FunctionAssignmentUpdateRequest,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:assign", "access:function:assign")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    assignment = session.query(FunctionAssignment).filter(FunctionAssignment.id == assignment_id, FunctionAssignment.tenant_id == tenant.id).one_or_none()
    if assignment is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Function assignment not found")
    if payload.identity_id is not None:
        if session.get(Identity, payload.identity_id) is None:
            raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Identity not found")
        assignment.identity_id = payload.identity_id
    if payload.organization_unit_id is not None:
        unit = session.query(OrganizationUnit).filter(OrganizationUnit.id == payload.organization_unit_id, OrganizationUnit.tenant_id == tenant.id).one_or_none()
        if unit is None:
            raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Organization unit not found")
        assignment.organization_unit_id = unit.id
    if payload.applies_to_subunits is not None:
        assignment.applies_to_subunits = payload.applies_to_subunits
    if payload.source is not None:
        assignment.source = payload.source.strip() or "direct"
    if payload.delegated_from_assignment_id is not None:
        assignment.delegated_from_assignment_id = payload.delegated_from_assignment_id
    if payload.acting_for_account_id is not None:
        assignment.acting_for_account_id = payload.acting_for_account_id
    if payload.valid_from is not None:
        assignment.valid_from = payload.valid_from
    if payload.valid_until is not None:
        assignment.valid_until = payload.valid_until
    if payload.is_active is not None:
        assignment.is_active = payload.is_active
    try:
        _validate_assignment_window(assignment.valid_from, assignment.valid_until)
    except AdminValidationError as exc:
        raise _http_admin_error(exc) from exc
    session.add(assignment)
    _record_access_change(
        session,
        collection=ACCESS_FUNCTION_ASSIGNMENTS_COLLECTION,
        resource_type="access_function_assignment",
        resource_id=assignment.id,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return _function_assignment_item(assignment)


@router.delete("/function-assignments/{assignment_id}", status_code=status.HTTP_204_NO_CONTENT)
def deactivate_function_assignment(
    assignment_id: str,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:assign", "access:function:assign")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    assignment = session.query(FunctionAssignment).filter(FunctionAssignment.id == assignment_id, FunctionAssignment.tenant_id == tenant.id).one_or_none()
    if assignment is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Function assignment not found")
    assignment.is_active = False
    session.add(assignment)
    _record_access_change(
        session,
        collection=ACCESS_FUNCTION_ASSIGNMENTS_COLLECTION,
        resource_type="access_function_assignment",
        resource_id=assignment.id,
        operation="deleted",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return None


@router.get("/function-delegations", response_model=FunctionDelegationListResponse)
def list_function_delegations(
    tenant_id: str | None = None,
    account_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:read", "access:function:read", "access:function:delegate")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    query = session.query(FunctionDelegation).filter(FunctionDelegation.tenant_id == tenant.id)
    if account_id:
        query = query.filter((FunctionDelegation.delegator_account_id == account_id) | (FunctionDelegation.delegate_account_id == account_id))
    delegations = query.order_by(FunctionDelegation.created_at.desc()).all()
    return FunctionDelegationListResponse(delegations=[_function_delegation_item(item) for item in delegations])


@router.post("/function-delegations", response_model=FunctionDelegationAdminItem, status_code=status.HTTP_201_CREATED)
def create_function_delegation(
    payload: FunctionDelegationCreateRequest,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:assign", "access:function:delegate")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    assignment = session.query(FunctionAssignment).filter(FunctionAssignment.id == payload.function_assignment_id, FunctionAssignment.tenant_id == tenant.id).one_or_none()
    if assignment is None:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Function assignment not found")
    function = session.query(Function).filter(Function.id == assignment.function_id, Function.tenant_id == tenant.id).one_or_none()
    if function is None:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Function not found")
    if payload.mode == "delegate" and not function.delegable:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="This function cannot be delegated.")
    if payload.mode == "act_in_place" and not function.act_in_place_allowed:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="This function does not permit acting in place.")
    delegate = session.get(Account, payload.delegate_account_id)
    if delegate is None:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Delegate account not found")
    if delegate.id == assignment.account_id:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail="Delegate account must differ from delegator account.")
    try:
        _validate_assignment_window(payload.valid_from, payload.valid_until)
    except AdminValidationError as exc:
        raise _http_admin_error(exc) from exc
    delegation = FunctionDelegation(
        tenant_id=tenant.id,
        function_assignment_id=assignment.id,
        delegator_account_id=assignment.account_id,
        delegate_account_id=delegate.id,
        mode=payload.mode,
        reason=payload.reason.strip() if payload.reason else None,
        valid_from=payload.valid_from,
        valid_until=payload.valid_until,
        is_active=payload.is_active,
    )
    session.add(delegation)
    try:
        session.flush()
    except IntegrityError as exc:
        raise _http_admin_error(AdminConflictError("This function delegation already exists.")) from exc
    _record_access_change(
        session,
        collection=ACCESS_FUNCTION_DELEGATIONS_COLLECTION,
        resource_type="access_function_delegation",
        resource_id=delegation.id,
        operation="created",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return _function_delegation_item(delegation)


@router.patch("/function-delegations/{delegation_id}", response_model=FunctionDelegationAdminItem)
def update_function_delegation(
    delegation_id: str,
    payload: FunctionDelegationUpdateRequest,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:assign", "access:function:delegate")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    delegation = session.query(FunctionDelegation).filter(FunctionDelegation.id == delegation_id, FunctionDelegation.tenant_id == tenant.id).one_or_none()
    if delegation is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Function delegation not found")
    if payload.reason is not None:
        delegation.reason = payload.reason.strip() or None
    if payload.valid_from is not None:
        delegation.valid_from = payload.valid_from
    if payload.valid_until is not None:
        delegation.valid_until = payload.valid_until
    if payload.is_active is not None:
        delegation.is_active = payload.is_active
    if payload.revoked is True:
        delegation.revoked_at = utc_now()
        delegation.is_active = False
    try:
        _validate_assignment_window(delegation.valid_from, delegation.valid_until)
    except AdminValidationError as exc:
        raise _http_admin_error(exc) from exc
    session.add(delegation)
    _record_access_change(
        session,
        collection=ACCESS_FUNCTION_DELEGATIONS_COLLECTION,
        resource_type="access_function_delegation",
        resource_id=delegation.id,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return _function_delegation_item(delegation)


@router.delete("/function-delegations/{delegation_id}", status_code=status.HTTP_204_NO_CONTENT)
def revoke_function_delegation(
    delegation_id: str,
    tenant_id: str | None = None,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("admin:roles:assign", "access:function:delegate")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    delegation = session.query(FunctionDelegation).filter(FunctionDelegation.id == delegation_id, FunctionDelegation.tenant_id == tenant.id).one_or_none()
    if delegation is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Function delegation not found")
    delegation.revoked_at = utc_now()
    delegation.is_active = False
    session.add(delegation)
    _record_access_change(
        session,
        collection=ACCESS_FUNCTION_DELEGATIONS_COLLECTION,
        resource_type="access_function_delegation",
        resource_id=delegation.id,
        operation="deleted",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return None


def _full_users_delta_response(session: Session, tenant: Tenant) -> UserListDeltaResponse:
    users = session.query(User).filter(User.tenant_id == tenant.id).order_by(User.display_name.asc(), User.email.asc()).all()
    owner_ids = tenant_owner_user_ids(session, tenant.id)
    return UserListDeltaResponse(
        users=[_user_item(session, user, owner_ids=owner_ids) for user in users],
        deleted=[],
        watermark=_access_delta_watermark(session, tenant.id, (ACCESS_USERS_COLLECTION,)),
        has_more=False,
        full=True,
    )


def _users_delta_response(session: Session, tenant: Tenant, *, since: str, limit: int) -> UserListDeltaResponse:
    entries, has_more = _access_delta_entries(session, tenant_id=tenant.id, collections=(ACCESS_USERS_COLLECTION,), since=since, limit=limit)
    if entries is None:
        return _full_users_delta_response(session, tenant)
    changed_ids = _changed_ids(entries, "access_user")
    visible = {
        user.id: user
        for user in (
            session.query(User).filter(User.tenant_id == tenant.id, User.id.in_(changed_ids)).all()
            if changed_ids else []
        )
    }
    owner_ids = tenant_owner_user_ids(session, tenant.id)
    deleted = [
        _delta_deleted_item(entry)
        for entry in entries
        if entry.resource_type == "access_user" and entry.resource_id not in visible
    ]
    return UserListDeltaResponse(
        users=[_user_item(session, user, owner_ids=owner_ids) for user in visible.values()],
        deleted=deleted,
        watermark=_access_delta_response_watermark(session, tenant_id=tenant.id, collections=(ACCESS_USERS_COLLECTION,), entries=entries, has_more=has_more),
        has_more=has_more,
        full=False,
    )


@router.get("/users/delta", response_model=UserListDeltaResponse)
def list_users_delta(
    tenant_id: str | None = Query(default=None),
    since: str | None = None,
    limit: int = Query(default=500, ge=1, le=1000),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:users:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    if since is None:
        return _full_users_delta_response(session, tenant)
    return _users_delta_response(session, tenant, since=since, limit=limit)


@router.get("/users", response_model=UserListResponse)
def list_users(
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:users:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    users = session.query(User).filter(User.tenant_id == tenant.id).order_by(User.display_name.asc(), User.email.asc()).all()
    owner_ids = tenant_owner_user_ids(session, tenant.id)
    return UserListResponse(users=[_user_item(session, user, owner_ids=owner_ids) for user in users])


@router.post("/users", response_model=UserCreateResponse, status_code=status.HTTP_201_CREATED)
def create_user(
    payload: UserCreateRequest,
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(get_api_principal),
):
    _require_permission(principal, "admin:users:create")
    if payload.group_ids:
        _require_permission(principal, "admin:groups:manage_members")
    if payload.role_ids:
        _require_permission(principal, "admin:roles:assign")
    tenant = _resolve_tenant(session, principal, tenant_id)
    try:
        result = create_membership(
            session,
            tenant=tenant,
            email=payload.email,
            display_name=payload.display_name,
            password=payload.password,
            password_reset_required=payload.password_reset_required,
            is_active=payload.is_active,
        )
        set_user_groups(session, user=result.user, group_ids=payload.group_ids)
        assert_can_delegate_roles(session, actor_scopes=principal.scopes, role_ids=payload.role_ids, tenant_id=tenant.id)
        set_user_roles(session, user=result.user, role_ids=payload.role_ids)
        assert_tenant_owner_exists(session, tenant.id)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_USERS_COLLECTION,
        resource_type="access_user",
        resource_id=result.user.id,
        operation="created",
        tenant_id=tenant.id,
        principal=principal,
    )
    if result.account_created:
        _record_access_change(
            session,
            collection=ACCESS_SYSTEM_ACCOUNTS_COLLECTION,
            resource_type="access_system_account",
            resource_id=result.account.id,
            operation="created",
            tenant_id=None,
            principal=principal,
        )
    _record_many_access_changes(
        session,
        collection=ACCESS_GROUPS_COLLECTION,
        resource_type="access_group",
        resource_ids=payload.group_ids,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    _record_many_access_changes(
        session,
        collection=ACCESS_ROLES_COLLECTION,
        resource_type="access_role",
        resource_ids=payload.role_ids,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    audit_event(
        session,
        tenant_id=tenant.id,
        user_id=principal.user.id,
        action="user.created",
        object_type="user",
        object_id=result.user.id,
        details={
            "email": result.account.email,
            "account_created": result.account_created,
            "group_ids": payload.group_ids,
            "role_ids": payload.role_ids,
        },
    )
    session.commit()
    return UserCreateResponse(
        user=_user_item(session, result.user),
        account_created=result.account_created,
        temporary_password=result.temporary_password,
    )


@router.patch("/users/{user_id}", response_model=UserAdminItem)
def update_user(
    user_id: str,
    payload: UserUpdateRequest,
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(get_api_principal),
):
    if "display_name" in payload.model_fields_set:
        _require_permission(principal, "admin:users:update")
    if payload.is_active is not None:
        _require_permission(principal, "admin:users:suspend")
    if payload.group_ids is not None:
        _require_permission(principal, "admin:groups:manage_members")
    if payload.role_ids is not None:
        _require_permission(principal, "admin:roles:assign")
    tenant = _resolve_tenant(session, principal, tenant_id)
    user = session.query(User).filter(User.id == user_id, User.tenant_id == tenant.id).one_or_none()
    if user is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="User not found")
    previous_group_ids = _current_user_group_ids(session, user) if payload.group_ids is not None else set()
    previous_role_ids = _current_user_role_ids(session, user) if payload.role_ids is not None else set()
    try:
        if payload.display_name is not None:
            user.display_name = payload.display_name.strip() or None
        if payload.is_active is not None:
            user.is_active = payload.is_active
        session.add(user)
        if payload.group_ids is not None:
            set_user_groups(session, user=user, group_ids=payload.group_ids)
        if payload.role_ids is not None:
            assert_can_delegate_roles(session, actor_scopes=principal.scopes, role_ids=payload.role_ids, tenant_id=tenant.id)
            set_user_roles(session, user=user, role_ids=payload.role_ids)
        assert_tenant_owner_exists(session, tenant.id)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_USERS_COLLECTION,
        resource_type="access_user",
        resource_id=user.id,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    if payload.group_ids is not None:
        _record_many_access_changes(
            session,
            collection=ACCESS_GROUPS_COLLECTION,
            resource_type="access_group",
            resource_ids=previous_group_ids | set(payload.group_ids),
            operation="updated",
            tenant_id=tenant.id,
            principal=principal,
        )
    if payload.role_ids is not None:
        _record_many_access_changes(
            session,
            collection=ACCESS_ROLES_COLLECTION,
            resource_type="access_role",
            resource_ids=previous_role_ids | set(payload.role_ids),
            operation="updated",
            tenant_id=tenant.id,
            principal=principal,
        )
    audit_event(
        session,
        tenant_id=tenant.id,
        user_id=principal.user.id,
        action="user.updated",
        object_type="user",
        object_id=user.id,
        details=payload.model_dump(exclude_none=True),
    )
    session.commit()
    return _user_item(session, user)


def _full_groups_delta_response(session: Session, tenant: Tenant) -> GroupListDeltaResponse:
    groups = session.query(Group).filter(Group.tenant_id == tenant.id).order_by(Group.name.asc()).all()
    return GroupListDeltaResponse(
        groups=[_group_summary(session, group) for group in groups],
        deleted=[],
        watermark=_access_delta_watermark(session, tenant.id, (ACCESS_GROUPS_COLLECTION,)),
        has_more=False,
        full=True,
    )


def _groups_delta_response(session: Session, tenant: Tenant, *, since: str, limit: int) -> GroupListDeltaResponse:
    entries, has_more = _access_delta_entries(session, tenant_id=tenant.id, collections=(ACCESS_GROUPS_COLLECTION,), since=since, limit=limit)
    if entries is None:
        return _full_groups_delta_response(session, tenant)
    changed_ids = _changed_ids(entries, "access_group")
    visible = {
        group.id: group
        for group in (
            session.query(Group).filter(Group.tenant_id == tenant.id, Group.id.in_(changed_ids)).all()
            if changed_ids else []
        )
    }
    deleted = [
        _delta_deleted_item(entry)
        for entry in entries
        if entry.resource_type == "access_group" and entry.resource_id not in visible
    ]
    return GroupListDeltaResponse(
        groups=[_group_summary(session, group) for group in visible.values()],
        deleted=deleted,
        watermark=_access_delta_response_watermark(session, tenant_id=tenant.id, collections=(ACCESS_GROUPS_COLLECTION,), entries=entries, has_more=has_more),
        has_more=has_more,
        full=False,
    )


@router.get("/groups/delta", response_model=GroupListDeltaResponse)
def list_groups_delta(
    tenant_id: str | None = Query(default=None),
    since: str | None = None,
    limit: int = Query(default=500, ge=1, le=1000),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:groups:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    if since is None:
        return _full_groups_delta_response(session, tenant)
    return _groups_delta_response(session, tenant, since=since, limit=limit)


@router.get("/groups", response_model=GroupListResponse)
def list_groups(
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:groups:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    groups = session.query(Group).filter(Group.tenant_id == tenant.id).order_by(Group.name.asc()).all()
    return GroupListResponse(groups=[_group_summary(session, group) for group in groups])


@router.post("/groups", response_model=GroupSummary, status_code=status.HTTP_201_CREATED)
def create_group(
    payload: GroupCreateRequest,
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(get_api_principal),
):
    _require_permission(principal, "admin:groups:write")
    if payload.member_ids:
        _require_permission(principal, "admin:groups:manage_members")
    if payload.role_ids:
        _require_permission(principal, "admin:roles:assign")
    tenant = _resolve_tenant(session, principal, tenant_id)
    try:
        assert_custom_groups_allowed(session, tenant)
    except AdminConflictError as exc:
        raise _http_admin_error(exc) from exc
    group_slug = slugify(payload.slug)
    if session.query(Group).filter(Group.tenant_id == tenant.id, Group.slug == group_slug).count():
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="A group with this slug already exists")
    group = Group(
        tenant_id=tenant.id,
        slug=group_slug,
        name=payload.name.strip(),
        description=payload.description.strip() if payload.description else None,
        is_active=payload.is_active,
    )
    session.add(group)
    session.flush()
    try:
        set_group_members(session, group=group, user_ids=payload.member_ids)
        assert_can_delegate_roles(session, actor_scopes=principal.scopes, role_ids=payload.role_ids, tenant_id=tenant.id)
        set_group_roles(session, group=group, role_ids=payload.role_ids)
        assert_tenant_owner_exists(session, tenant.id)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_GROUPS_COLLECTION,
        resource_type="access_group",
        resource_id=group.id,
        operation="created",
        tenant_id=tenant.id,
        principal=principal,
    )
    _record_many_access_changes(
        session,
        collection=ACCESS_USERS_COLLECTION,
        resource_type="access_user",
        resource_ids=payload.member_ids,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    _record_many_access_changes(
        session,
        collection=ACCESS_ROLES_COLLECTION,
        resource_type="access_role",
        resource_ids=payload.role_ids,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    audit_event(
        session,
        tenant_id=tenant.id,
        user_id=principal.user.id,
        action="group.created",
        object_type="group",
        object_id=group.id,
        details={"slug": group.slug, "member_ids": payload.member_ids, "role_ids": payload.role_ids},
    )
    session.commit()
    return _group_summary(session, group)


@router.patch("/groups/{group_id}", response_model=GroupSummary)
def update_group(
    group_id: str,
    payload: GroupUpdateRequest,
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(get_api_principal),
):
    if any(field in payload.model_fields_set for field in ("name", "description", "is_active")):
        _require_permission(principal, "admin:groups:write")
    if payload.member_ids is not None:
        _require_permission(principal, "admin:groups:manage_members")
    if payload.role_ids is not None:
        _require_permission(principal, "admin:roles:assign")
    tenant = _resolve_tenant(session, principal, tenant_id)
    group = session.query(Group).filter(Group.id == group_id, Group.tenant_id == tenant.id).one_or_none()
    if group is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Group not found")
    previous_member_ids = _current_group_member_ids(session, group) if payload.member_ids is not None else set()
    previous_role_ids = _current_group_role_ids(session, group) if payload.role_ids is not None else set()
    try:
        ensure_group_mutation_allowed(group, requested_active=payload.is_active)
        if group.system_template_id is None and payload.name is not None:
            group.name = payload.name.strip()
        if group.system_template_id is None and "description" in payload.model_fields_set:
            group.description = payload.description.strip() if payload.description and payload.description.strip() else None
        if payload.is_active is not None:
            group.is_active = payload.is_active
        session.add(group)
        if payload.member_ids is not None:
            set_group_members(session, group=group, user_ids=payload.member_ids)
        if payload.role_ids is not None:
            assert_can_delegate_roles(session, actor_scopes=principal.scopes, role_ids=payload.role_ids, tenant_id=tenant.id)
            set_group_roles(session, group=group, role_ids=payload.role_ids)
        assert_tenant_owner_exists(session, tenant.id)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_GROUPS_COLLECTION,
        resource_type="access_group",
        resource_id=group.id,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    if payload.member_ids is not None:
        _record_many_access_changes(
            session,
            collection=ACCESS_USERS_COLLECTION,
            resource_type="access_user",
            resource_ids=previous_member_ids | set(payload.member_ids),
            operation="updated",
            tenant_id=tenant.id,
            principal=principal,
        )
    if payload.role_ids is not None:
        _record_many_access_changes(
            session,
            collection=ACCESS_ROLES_COLLECTION,
            resource_type="access_role",
            resource_ids=previous_role_ids | set(payload.role_ids),
            operation="updated",
            tenant_id=tenant.id,
            principal=principal,
        )
    audit_event(
        session,
        tenant_id=tenant.id,
        user_id=principal.user.id,
        action="group.updated",
        object_type="group",
        object_id=group.id,
        details=payload.model_dump(exclude_unset=True),
    )
    session.commit()
    return _group_summary(session, group)


def _full_roles_delta_response(session: Session, tenant: Tenant) -> RoleListDeltaResponse:
    ensure_default_roles(session, tenant)
    session.commit()
    roles = session.query(Role).filter(Role.tenant_id == tenant.id).order_by(Role.is_builtin.desc(), Role.name.asc()).all()
    return RoleListDeltaResponse(
        roles=[_role_summary(session, role) for role in roles],
        deleted=[],
        watermark=_access_delta_watermark(session, tenant.id, (ACCESS_ROLES_COLLECTION,)),
        has_more=False,
        full=True,
    )


def _roles_delta_response(session: Session, tenant: Tenant, *, since: str, limit: int) -> RoleListDeltaResponse:
    entries, has_more = _access_delta_entries(session, tenant_id=tenant.id, collections=(ACCESS_ROLES_COLLECTION,), since=since, limit=limit)
    if entries is None:
        return _full_roles_delta_response(session, tenant)
    changed_ids = _changed_ids(entries, "access_role")
    visible = {
        role.id: role
        for role in (
            session.query(Role).filter(Role.tenant_id == tenant.id, Role.id.in_(changed_ids)).all()
            if changed_ids else []
        )
    }
    deleted = [
        _delta_deleted_item(entry)
        for entry in entries
        if entry.resource_type == "access_role" and entry.resource_id not in visible
    ]
    return RoleListDeltaResponse(
        roles=[_role_summary(session, role) for role in visible.values()],
        deleted=deleted,
        watermark=_access_delta_response_watermark(session, tenant_id=tenant.id, collections=(ACCESS_ROLES_COLLECTION,), entries=entries, has_more=has_more),
        has_more=has_more,
        full=False,
    )


@router.get("/roles/delta", response_model=RoleListDeltaResponse)
def list_roles_delta(
    tenant_id: str | None = Query(default=None),
    since: str | None = None,
    limit: int = Query(default=500, ge=1, le=1000),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:roles:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    if since is None:
        return _full_roles_delta_response(session, tenant)
    return _roles_delta_response(session, tenant, since=since, limit=limit)


@router.get("/roles", response_model=RoleListResponse)
def list_roles(
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:roles:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    ensure_default_roles(session, tenant)
    session.commit()
    roles = session.query(Role).filter(Role.tenant_id == tenant.id).order_by(Role.is_builtin.desc(), Role.name.asc()).all()
    return RoleListResponse(roles=[_role_summary(session, role) for role in roles])


@router.post("/roles", response_model=RoleSummary, status_code=status.HTTP_201_CREATED)
def create_role(
    payload: RoleCreateRequest,
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:roles:write")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    try:
        assert_custom_roles_allowed(session, tenant)
        assert_can_delegate_tenant_permissions(principal.scopes, payload.permissions)
        role = create_custom_role(
            session,
            tenant=tenant,
            slug=payload.slug,
            name=payload.name,
            description=payload.description,
            permissions=payload.permissions,
        )
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_ROLES_COLLECTION,
        resource_type="access_role",
        resource_id=role.id,
        operation="created",
        tenant_id=tenant.id,
        principal=principal,
    )
    audit_event(
        session,
        tenant_id=tenant.id,
        user_id=principal.user.id,
        action="role.created",
        object_type="role",
        object_id=role.id,
        details={"slug": role.slug, "permissions": role.permissions},
    )
    session.commit()
    return _role_summary(session, role)


@router.patch("/roles/{role_id}", response_model=RoleSummary)
def update_role(
    role_id: str,
    payload: RoleUpdateRequest,
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:roles:write")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    role = session.query(Role).filter(Role.id == role_id, Role.tenant_id == tenant.id).one_or_none()
    if role is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Role not found")
    affected_user_ids = _tenant_user_ids_for_role(session, role.id, tenant.id)
    affected_group_ids = _tenant_group_ids_for_role(session, role.id, tenant.id)
    try:
        ensure_role_mutation_allowed(role, requested_assignable=payload.is_assignable)
        if payload.permissions is not None:
            assert_can_delegate_tenant_permissions(principal.scopes, payload.permissions)
        update_custom_role(
            session,
            role=role,
            name=payload.name,
            description=payload.description,
            permissions=payload.permissions,
            is_assignable=payload.is_assignable,
        )
        assert_tenant_owner_exists(session, tenant.id)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_ROLES_COLLECTION,
        resource_type="access_role",
        resource_id=role.id,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    _record_many_access_changes(
        session,
        collection=ACCESS_USERS_COLLECTION,
        resource_type="access_user",
        resource_ids=affected_user_ids,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    _record_many_access_changes(
        session,
        collection=ACCESS_GROUPS_COLLECTION,
        resource_type="access_group",
        resource_ids=affected_group_ids,
        operation="updated",
        tenant_id=tenant.id,
        principal=principal,
    )
    audit_event(
        session,
        tenant_id=tenant.id,
        user_id=principal.user.id,
        action="role.updated",
        object_type="role",
        object_id=role.id,
        details=payload.model_dump(),
    )
    session.commit()
    return _role_summary(session, role)


@router.delete("/roles/{role_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_role(
    role_id: str,
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:roles:write")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    role = session.query(Role).filter(Role.id == role_id, Role.tenant_id == tenant.id).one_or_none()
    if role is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Role not found")
    try:
        if role.system_template_id:
            raise AdminConflictError("Centrally managed roles can only be removed from System administration.")
        role_slug = role.slug
        delete_custom_role(session, role)
        assert_tenant_owner_exists(session, tenant.id)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_ROLES_COLLECTION,
        resource_type="access_role",
        resource_id=role_id,
        operation="deleted",
        tenant_id=tenant.id,
        principal=principal,
        payload={"slug": role_slug},
    )
    audit_event(
        session,
        tenant_id=tenant.id,
        user_id=principal.user.id,
        action="role.deleted",
        object_type="role",
        object_id=role_id,
        details={"slug": role_slug},
    )
    session.commit()
    return None


def _full_system_roles_delta_response(session: Session) -> RoleListDeltaResponse:
    ensure_default_roles(session, None)
    session.commit()
    roles = session.query(Role).filter(Role.tenant_id.is_(None)).order_by(Role.name.asc()).all()
    return RoleListDeltaResponse(
        roles=[_role_summary(session, role) for role in roles],
        deleted=[],
        watermark=_access_delta_watermark(session, None, (ACCESS_SYSTEM_ROLES_COLLECTION,)),
        has_more=False,
        full=True,
    )


def _system_roles_delta_response(session: Session, *, since: str, limit: int) -> RoleListDeltaResponse:
    entries, has_more = _access_delta_entries(session, tenant_id=None, collections=(ACCESS_SYSTEM_ROLES_COLLECTION,), since=since, limit=limit)
    if entries is None:
        return _full_system_roles_delta_response(session)
    changed_ids = _changed_ids(entries, "access_system_role")
    visible = {
        role.id: role
        for role in (
            session.query(Role).filter(Role.tenant_id.is_(None), Role.id.in_(changed_ids)).all()
            if changed_ids else []
        )
    }
    deleted = [
        _delta_deleted_item(entry)
        for entry in entries
        if entry.resource_type == "access_system_role" and entry.resource_id not in visible
    ]
    return RoleListDeltaResponse(
        roles=[_role_summary(session, role) for role in visible.values()],
        deleted=deleted,
        watermark=_access_delta_response_watermark(session, tenant_id=None, collections=(ACCESS_SYSTEM_ROLES_COLLECTION,), entries=entries, has_more=has_more),
        has_more=has_more,
        full=False,
    )


@router.get("/system/roles/delta", response_model=RoleListDeltaResponse)
def list_system_roles_delta(
    since: str | None = None,
    limit: int = Query(default=500, ge=1, le=1000),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("system:roles:read", "system:access:read")),
):
    del principal
    if since is None:
        return _full_system_roles_delta_response(session)
    return _system_roles_delta_response(session, since=since, limit=limit)


@router.get("/system/roles", response_model=RoleListResponse)
def list_system_roles(
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("system:roles:read", "system:access:read")),
):
    ensure_default_roles(session, None)
    session.commit()
    roles = session.query(Role).filter(Role.tenant_id.is_(None)).order_by(Role.name.asc()).all()
    return RoleListResponse(roles=[_role_summary(session, role) for role in roles])


@router.post("/system/roles", response_model=RoleSummary, status_code=status.HTTP_201_CREATED)
def create_system_role_endpoint(
    payload: RoleCreateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("system:roles:write")),
):
    try:
        assert_can_delegate_system_permissions(principal.scopes, payload.permissions)
        role = create_system_role(
            session,
            slug=payload.slug,
            name=payload.name,
            description=payload.description,
            permissions=payload.permissions,
        )
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_SYSTEM_ROLES_COLLECTION,
        resource_type="access_system_role",
        resource_id=role.id,
        operation="created",
        tenant_id=None,
        principal=principal,
    )
    audit_from_principal(
        session, principal, action="system_role.created", scope="system", object_type="role", object_id=role.id,
        details={"slug": role.slug, "permissions": role.permissions},
    )
    session.commit()
    return _role_summary(session, role)


@router.patch("/system/roles/{role_id}", response_model=RoleSummary)
def update_system_role_endpoint(
    role_id: str,
    payload: RoleUpdateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("system:roles:write")),
):
    role = session.query(Role).filter(Role.id == role_id, Role.tenant_id.is_(None)).one_or_none()
    if role is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="System role not found")
    affected_account_ids = _system_account_ids_for_role(session, role.id)
    try:
        assert_can_delegate_system_permissions(principal.scopes, payload.permissions)
        update_system_role(
            session,
            role=role,
            name=payload.name,
            description=payload.description,
            permissions=payload.permissions,
            is_assignable=payload.is_assignable,
        )
        assert_system_owner_exists(session)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_SYSTEM_ROLES_COLLECTION,
        resource_type="access_system_role",
        resource_id=role.id,
        operation="updated",
        tenant_id=None,
        principal=principal,
    )
    _record_many_access_changes(
        session,
        collection=ACCESS_SYSTEM_ACCOUNTS_COLLECTION,
        resource_type="access_system_account",
        resource_ids=affected_account_ids,
        operation="updated",
        tenant_id=None,
        principal=principal,
    )
    audit_from_principal(
        session, principal, action="system_role.updated", scope="system", object_type="role", object_id=role.id,
        details=payload.model_dump(),
    )
    session.commit()
    return _role_summary(session, role)


@router.delete("/system/roles/{role_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_system_role_endpoint(
    role_id: str,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("system:roles:write")),
):
    role = session.query(Role).filter(Role.id == role_id, Role.tenant_id.is_(None)).one_or_none()
    if role is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="System role not found")
    try:
        role_slug = role.slug
        delete_system_role(session, role)
        assert_system_owner_exists(session)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_SYSTEM_ROLES_COLLECTION,
        resource_type="access_system_role",
        resource_id=role_id,
        operation="deleted",
        tenant_id=None,
        principal=principal,
        payload={"slug": role_slug},
    )
    audit_from_principal(
        session, principal, action="system_role.deleted", scope="system", object_type="role", object_id=role_id,
        details={"slug": role_slug},
    )
    session.commit()
    return None


_SYSTEM_ACCOUNTS_DELTA_COLLECTIONS = (ACCESS_SYSTEM_ACCOUNTS_COLLECTION, ACCESS_SYSTEM_ROLES_COLLECTION)


def _full_system_accounts_delta_response(session: Session) -> SystemAccountListDeltaResponse:
    ensure_default_roles(session, None)
    session.commit()
    system_roles = session.query(Role).filter(Role.tenant_id.is_(None)).order_by(Role.name.asc()).all()
    accounts = session.query(Account).order_by(Account.email.asc()).all()
    return SystemAccountListDeltaResponse(
        accounts=[_system_account_item(session, account) for account in accounts],
        roles=[_role_summary(session, role) for role in system_roles],
        deleted=[],
        watermark=_access_delta_watermark(session, None, _SYSTEM_ACCOUNTS_DELTA_COLLECTIONS),
        has_more=False,
        full=True,
    )


def _system_accounts_delta_response(session: Session, *, since: str, limit: int) -> SystemAccountListDeltaResponse:
    entries, has_more = _access_delta_entries(session, tenant_id=None, collections=_SYSTEM_ACCOUNTS_DELTA_COLLECTIONS, since=since, limit=limit)
    if entries is None:
        return _full_system_accounts_delta_response(session)
    account_ids = _changed_ids(entries, "access_system_account")
    role_ids = _changed_ids(entries, "access_system_role")
    visible_accounts = {
        account.id: account
        for account in (
            session.query(Account).filter(Account.id.in_(account_ids)).all()
            if account_ids else []
        )
    }
    visible_roles = {
        role.id: role
        for role in (
            session.query(Role).filter(Role.tenant_id.is_(None), Role.id.in_(role_ids)).all()
            if role_ids else []
        )
    }
    deleted = [
        _delta_deleted_item(entry)
        for entry in entries
        if (
            (entry.resource_type == "access_system_account" and entry.resource_id not in visible_accounts)
            or (entry.resource_type == "access_system_role" and entry.resource_id not in visible_roles)
        )
    ]
    return SystemAccountListDeltaResponse(
        accounts=[_system_account_item(session, account) for account in visible_accounts.values()],
        roles=[_role_summary(session, role) for role in visible_roles.values()],
        deleted=deleted,
        watermark=_access_delta_response_watermark(session, tenant_id=None, collections=_SYSTEM_ACCOUNTS_DELTA_COLLECTIONS, entries=entries, has_more=has_more),
        has_more=has_more,
        full=False,
    )


@router.get("/system/accounts/delta", response_model=SystemAccountListDeltaResponse)
def list_system_accounts_delta(
    since: str | None = None,
    limit: int = Query(default=500, ge=1, le=1000),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("system:accounts:read", "system:access:read")),
):
    del principal
    if since is None:
        return _full_system_accounts_delta_response(session)
    return _system_accounts_delta_response(session, since=since, limit=limit)


@router.get("/system/accounts", response_model=SystemAccountListResponse)
def list_system_accounts(
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("system:accounts:read", "system:access:read")),
):
    ensure_default_roles(session, None)
    session.commit()
    system_roles = session.query(Role).filter(Role.tenant_id.is_(None)).order_by(Role.name.asc()).all()
    accounts = session.query(Account).order_by(Account.email.asc()).all()
    return SystemAccountListResponse(
        accounts=[_system_account_item(session, account) for account in accounts],
        roles=[_role_summary(session, role) for role in system_roles],
    )


@router.patch("/system/accounts/{account_id}", response_model=SystemAccountItem)
def update_system_account(
    account_id: str,
    payload: SystemAccountUpdateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(get_api_principal),
):
    if "display_name" in payload.model_fields_set and not has_scope(principal, "system:accounts:update"):
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Missing scope: system:accounts:update")
    if payload.is_active is not None and not has_scope(principal, "system:accounts:suspend"):
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Missing scope: system:accounts:suspend")
    if payload.role_ids is not None:
        _require_system_role_assignment(principal)
    account = session.get(Account, account_id)
    if account is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Account not found")
    previous_role_ids = _current_system_role_ids(session, account) if payload.role_ids is not None else set()
    if "display_name" in payload.model_fields_set:
        account.display_name = payload.display_name.strip() if payload.display_name else None
    if payload.is_active is not None:
        account.is_active = payload.is_active
    session.add(account)
    try:
        if payload.role_ids is not None:
            _require_system_role_assignment(principal)
            assert_can_delegate_system_roles(session, actor_scopes=principal.scopes, role_ids=payload.role_ids)
            set_system_roles(session, account=account, role_ids=payload.role_ids)
        else:
            session.flush()
        assert_system_owner_exists(session)
        if not account.is_active:
            tenant_ids = [
                row[0]
                for row in session.query(User.tenant_id)
                .join(Tenant, Tenant.id == User.tenant_id)
                .filter(User.account_id == account.id, User.is_active.is_(True), Tenant.is_active.is_(True))
                .distinct()
                .all()
            ]
            for tenant_id in tenant_ids:
                assert_tenant_owner_exists(session, tenant_id)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_SYSTEM_ACCOUNTS_COLLECTION,
        resource_type="access_system_account",
        resource_id=account.id,
        operation="updated",
        tenant_id=None,
        principal=principal,
    )
    if payload.role_ids is not None:
        _record_many_access_changes(
            session,
            collection=ACCESS_SYSTEM_ROLES_COLLECTION,
            resource_type="access_system_role",
            resource_ids=previous_role_ids | set(payload.role_ids),
            operation="updated",
            tenant_id=None,
            principal=principal,
        )
    audit_from_principal(
        session,
        principal,
        action="system_account.updated",
        scope="system",
        object_type="account",
        object_id=account.id,
        details=payload.model_dump(exclude_unset=True),
    )
    session.commit()
    return _system_account_item(session, account)


@router.put("/system/accounts/{account_id}/roles", response_model=SystemAccountItem)
def update_system_account_roles(
    account_id: str,
    payload: SystemAccountRolesUpdateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_any_scope("system:roles:assign", "system:access:assign")),
):
    account = session.get(Account, account_id)
    if account is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Account not found")
    previous_role_ids = _current_system_role_ids(session, account)
    try:
        _require_system_role_assignment(principal)
        assert_can_delegate_system_roles(session, actor_scopes=principal.scopes, role_ids=payload.role_ids)
        set_system_roles(session, account=account, role_ids=payload.role_ids)
        assert_system_owner_exists(session)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_SYSTEM_ACCOUNTS_COLLECTION,
        resource_type="access_system_account",
        resource_id=account.id,
        operation="updated",
        tenant_id=None,
        principal=principal,
    )
    _record_many_access_changes(
        session,
        collection=ACCESS_SYSTEM_ROLES_COLLECTION,
        resource_type="access_system_role",
        resource_ids=previous_role_ids | set(payload.role_ids),
        operation="updated",
        tenant_id=None,
        principal=principal,
    )
    audit_from_principal(
        session,
        principal,
        action="system_access.updated",
        scope="system",
        object_type="account",
        object_id=account.id,
        details={"role_ids": payload.role_ids},
    )
    session.commit()
    return _system_account_item(session, account)


@router.post("/system/accounts", response_model=SystemAccountCreateResponse, status_code=status.HTTP_201_CREATED)
def create_system_account(
    payload: SystemAccountCreateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("system:accounts:create")),
):
    try:
        account, created, temporary_password = get_or_create_account(
            session,
            email=payload.email,
            display_name=payload.display_name,
            password=payload.password,
            password_reset_required=payload.password_reset_required,
        )
        if not created:
            raise AdminConflictError("A global account with this email already exists.")
        account.is_active = payload.is_active
        if payload.role_ids:
            _require_system_role_assignment(principal)
            assert_can_delegate_system_roles(session, actor_scopes=principal.scopes, role_ids=payload.role_ids)
        set_system_roles(session, account=account, role_ids=payload.role_ids)
        if payload.memberships:
            _require_permission(principal, "system:access:assign")
        _set_system_memberships(session, account, [item.model_dump() for item in payload.memberships])
        assert_system_owner_exists(session)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_SYSTEM_ACCOUNTS_COLLECTION,
        resource_type="access_system_account",
        resource_id=account.id,
        operation="created",
        tenant_id=None,
        principal=principal,
    )
    _record_many_access_changes(
        session,
        collection=ACCESS_SYSTEM_ROLES_COLLECTION,
        resource_type="access_system_role",
        resource_ids=payload.role_ids,
        operation="updated",
        tenant_id=None,
        principal=principal,
    )
    for membership in payload.memberships:
        user = session.query(User).filter(User.account_id == account.id, User.tenant_id == membership.tenant_id).one_or_none()
        if user:
            _record_access_change(
                session,
                collection=ACCESS_USERS_COLLECTION,
                resource_type="access_user",
                resource_id=user.id,
                operation="created",
                tenant_id=membership.tenant_id,
                principal=principal,
            )
        _record_many_access_changes(
            session,
            collection=ACCESS_GROUPS_COLLECTION,
            resource_type="access_group",
            resource_ids=membership.group_ids,
            operation="updated",
            tenant_id=membership.tenant_id,
            principal=principal,
        )
        _record_many_access_changes(
            session,
            collection=ACCESS_ROLES_COLLECTION,
            resource_type="access_role",
            resource_ids=membership.role_ids,
            operation="updated",
            tenant_id=membership.tenant_id,
            principal=principal,
        )
    audit_from_principal(
        session, principal, action="system_account.created", scope="system", object_type="account", object_id=account.id,
        details={"email": account.email, "tenant_ids": [item.tenant_id for item in payload.memberships], "role_ids": payload.role_ids},
    )
    session.commit()
    return SystemAccountCreateResponse(account=_system_account_item(session, account), temporary_password=temporary_password)


@router.put("/system/accounts/{account_id}/memberships", response_model=SystemAccountItem)
def update_system_account_memberships(
    account_id: str,
    payload: SystemAccountMembershipsUpdateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("system:accounts:update")),
):
    account = session.get(Account, account_id)
    if account is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Account not found")
    previous_users = {user.tenant_id: user for user in session.query(User).filter(User.account_id == account.id).all()}
    requested_tenant_ids = {item.tenant_id for item in payload.memberships}
    try:
        _require_permission(principal, "system:access:assign")
        _set_system_memberships(session, account, [item.model_dump() for item in payload.memberships])
        for tenant_id in {item.tenant_id for item in payload.memberships}:
            assert_tenant_owner_exists(session, tenant_id)
    except (AdminConflictError, AdminValidationError) as exc:
        raise _http_admin_error(exc) from exc
    _record_access_change(
        session,
        collection=ACCESS_SYSTEM_ACCOUNTS_COLLECTION,
        resource_type="access_system_account",
        resource_id=account.id,
        operation="updated",
        tenant_id=None,
        principal=principal,
    )
    for membership in payload.memberships:
        user = session.query(User).filter(User.account_id == account.id, User.tenant_id == membership.tenant_id).one_or_none()
        if user:
            _record_access_change(
                session,
                collection=ACCESS_USERS_COLLECTION,
                resource_type="access_user",
                resource_id=user.id,
                operation="created" if membership.tenant_id not in previous_users else "updated",
                tenant_id=membership.tenant_id,
                principal=principal,
            )
        _record_many_access_changes(
            session,
            collection=ACCESS_GROUPS_COLLECTION,
            resource_type="access_group",
            resource_ids=membership.group_ids,
            operation="updated",
            tenant_id=membership.tenant_id,
            principal=principal,
        )
        _record_many_access_changes(
            session,
            collection=ACCESS_ROLES_COLLECTION,
            resource_type="access_role",
            resource_ids=membership.role_ids,
            operation="updated",
            tenant_id=membership.tenant_id,
            principal=principal,
        )
    for tenant_id, user in previous_users.items():
        if tenant_id not in requested_tenant_ids:
            _record_access_change(
                session,
                collection=ACCESS_USERS_COLLECTION,
                resource_type="access_user",
                resource_id=user.id,
                operation="updated",
                tenant_id=tenant_id,
                principal=principal,
            )
    audit_from_principal(
        session, principal, action="system_memberships.updated", scope="system", object_type="account", object_id=account.id,
        details={"tenant_ids": [item.tenant_id for item in payload.memberships]},
    )
    session.commit()
    return _system_account_item(session, account)


def _full_api_keys_delta_response(session: Session, tenant: Tenant, *, include_revoked: bool) -> ApiKeyListDeltaResponse:
    query = session.query(ApiKey).filter(ApiKey.tenant_id == tenant.id)
    if not include_revoked:
        query = query.filter(ApiKey.revoked_at.is_(None))
    keys = query.order_by(ApiKey.created_at.desc()).all()
    return ApiKeyListDeltaResponse(
        api_keys=[_api_key_item(session, item) for item in keys],
        deleted=[],
        watermark=_access_delta_watermark(session, tenant.id, (ACCESS_API_KEYS_COLLECTION,)),
        has_more=False,
        full=True,
    )


def _api_keys_delta_response(session: Session, tenant: Tenant, *, include_revoked: bool, since: str, limit: int) -> ApiKeyListDeltaResponse:
    entries, has_more = _access_delta_entries(session, tenant_id=tenant.id, collections=(ACCESS_API_KEYS_COLLECTION,), since=since, limit=limit)
    if entries is None:
        return _full_api_keys_delta_response(session, tenant, include_revoked=include_revoked)
    changed_ids = _changed_ids(entries, "access_api_key")
    query = session.query(ApiKey).filter(ApiKey.tenant_id == tenant.id)
    if not include_revoked:
        query = query.filter(ApiKey.revoked_at.is_(None))
    visible = {
        item.id: item
        for item in (
            query.filter(ApiKey.id.in_(changed_ids)).all()
            if changed_ids else []
        )
    }
    deleted = [
        _delta_deleted_item(entry)
        for entry in entries
        if entry.resource_type == "access_api_key" and entry.resource_id not in visible
    ]
    return ApiKeyListDeltaResponse(
        api_keys=[_api_key_item(session, item) for item in visible.values()],
        deleted=deleted,
        watermark=_access_delta_response_watermark(session, tenant_id=tenant.id, collections=(ACCESS_API_KEYS_COLLECTION,), entries=entries, has_more=has_more),
        has_more=has_more,
        full=False,
    )


@router.get("/api-keys/delta", response_model=ApiKeyListDeltaResponse)
def list_api_keys_delta(
    tenant_id: str | None = Query(default=None),
    include_revoked: bool = Query(default=False),
    since: str | None = None,
    limit: int = Query(default=500, ge=1, le=1000),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:api_keys:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    if since is None:
        return _full_api_keys_delta_response(session, tenant, include_revoked=include_revoked)
    return _api_keys_delta_response(session, tenant, include_revoked=include_revoked, since=since, limit=limit)


@router.get("/api-keys", response_model=ApiKeyListResponse)
def list_api_keys(
    tenant_id: str | None = Query(default=None),
    include_revoked: bool = Query(default=False),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:api_keys:read")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    query = session.query(ApiKey).filter(ApiKey.tenant_id == tenant.id)
    if not include_revoked:
        query = query.filter(ApiKey.revoked_at.is_(None))
    keys = query.order_by(ApiKey.created_at.desc()).all()
    return ApiKeyListResponse(api_keys=[_api_key_item(session, item) for item in keys])


@router.post("/api-keys", response_model=AdminApiKeyCreateResponse, status_code=status.HTTP_201_CREATED)
def create_tenant_api_key(
    payload: AdminApiKeyCreateRequest,
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:api_keys:create")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    try:
        assert_api_keys_allowed(session, tenant)
    except AdminConflictError as exc:
        raise _http_admin_error(exc) from exc
    user_id = payload.user_id or principal.user.id
    user = session.query(User).filter(User.id == user_id, User.tenant_id == tenant.id, User.is_active.is_(True)).one_or_none()
    if user is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Active user not found")
    user_scopes = collect_user_scopes(session, user, include_system=False)
    requested = payload.scopes or ["campaign:read"]
    invalid = [scope for scope in requested if scope.startswith("system:") or not scopes_grant(user_scopes, scope)]
    if invalid:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_CONTENT,
            detail=f"API key scopes exceed the user's tenant permissions: {', '.join(invalid)}",
        )
    created = create_api_key(
        session,
        user=user,
        name=payload.name.strip(),
        scopes=sorted(set(requested)),
        expires_at=payload.expires_at,
    )
    audit_event(
        session,
        tenant_id=tenant.id,
        user_id=principal.user.id,
        action="api_key.created",
        object_type="api_key",
        object_id=created.model.id,
        details={"name": created.model.name, "prefix": created.model.prefix, "scopes": created.model.scopes, "owner_user_id": user.id},
    )
    _record_access_change(
        session,
        collection=ACCESS_API_KEYS_COLLECTION,
        resource_type="access_api_key",
        resource_id=created.model.id,
        operation="created",
        tenant_id=tenant.id,
        principal=principal,
    )
    session.commit()
    return AdminApiKeyCreateResponse(**_api_key_item(session, created.model).model_dump(), secret=created.secret)


@router.post("/api-keys/{api_key_id}/revoke", response_model=ApiKeyAdminItem)
def revoke_api_key(
    api_key_id: str,
    tenant_id: str | None = Query(default=None),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(require_scope("admin:api_keys:revoke")),
):
    tenant = _resolve_tenant(session, principal, tenant_id)
    item = session.query(ApiKey).filter(ApiKey.id == api_key_id, ApiKey.tenant_id == tenant.id).one_or_none()
    if item is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="API key not found")
    if item.revoked_at is None:
        item.revoked_at = utc_now()
        session.add(item)
        audit_event(
            session,
            tenant_id=tenant.id,
            user_id=principal.user.id,
            action="api_key.revoked",
            object_type="api_key",
            object_id=item.id,
            details={"name": item.name, "prefix": item.prefix},
        )
        _record_access_change(
            session,
            collection=ACCESS_API_KEYS_COLLECTION,
            resource_type="access_api_key",
            resource_id=item.id,
            operation="updated",
            tenant_id=tenant.id,
            principal=principal,
        )
        session.commit()
    return _api_key_item(session, item)