from __future__ import annotations

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

from govoplan_access.backend.admin.governance import assert_api_keys_allowed
from govoplan_access.backend.api.v1.admin_common import _resolve_tenant
from govoplan_access.backend.api.v1.admin_schemas import (
    ServiceAccountCreateRequest,
    ServiceAccountCredentialCreateRequest,
    ServiceAccountCredentialItem,
    ServiceAccountCredentialListResponse,
    ServiceAccountCredentialMutationResponse,
    ServiceAccountCredentialRevokeRequest,
    ServiceAccountCredentialRotateRequest,
    ServiceAccountCredentialSecretResponse,
    ServiceAccountItem,
    ServiceAccountListResponse,
    ServiceAccountRetireRequest,
    ServiceAccountUpdateRequest,
)
from govoplan_access.backend.service_accounts import (
    ServiceAccountConflictError,
    ServiceAccountCredentialNotFoundError,
    ServiceAccountCredentialSummary,
    ServiceAccountError,
    ServiceAccountNotFoundError,
    create_service_account,
    create_service_account_credential,
    get_service_account,
    list_service_accounts,
    list_service_account_credentials,
    revoke_service_account_credential,
    retire_service_account,
    rotate_service_account_credential,
    service_account_credential_summaries,
    update_service_account,
)
from govoplan_core.admin.common import AdminConflictError
from govoplan_core.audit.logging import audit_from_principal
from govoplan_core.auth import ApiPrincipal, require_scope
from govoplan_core.db.session import get_session


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


@router.get("", response_model=ServiceAccountListResponse)
def list_managed_service_accounts(
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(
        require_scope("access:service_account:read")
    ),
):
    tenant = _resolve_tenant(session, principal, None)
    items = list_service_accounts(
        session,
        tenant_id=tenant.id,
    )
    summaries = service_account_credential_summaries(
        session,
        service_accounts=items,
    )
    return ServiceAccountListResponse(
        items=[
            _service_account_item(item, summaries.get(item.id))
            for item in items
        ]
    )


@router.get(
    "/{service_account_id}",
    response_model=ServiceAccountItem,
)
def get_managed_service_account(
    service_account_id: str,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(
        require_scope("access:service_account:read")
    ),
):
    tenant = _resolve_tenant(session, principal, None)
    try:
        item = get_service_account(
            session,
            tenant_id=tenant.id,
            service_account_id=service_account_id,
        )
    except ServiceAccountError as exc:
        raise _service_account_http_error(exc) from exc
    summary = service_account_credential_summaries(
        session,
        service_accounts=(item,),
    )[item.id]
    return _service_account_item(item, summary)


@router.post(
    "",
    response_model=ServiceAccountItem,
    status_code=status.HTTP_201_CREATED,
)
def create_managed_service_account(
    payload: ServiceAccountCreateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(
        require_scope("access:service_account:write")
    ),
):
    tenant = _resolve_tenant(session, principal, None)
    try:
        item = create_service_account(
            session,
            tenant=tenant,
            principal=principal,
            name=payload.name,
            description=payload.description,
            scope_ceiling=payload.scope_ceiling,
        )
    except (ServiceAccountError, PermissionError) as exc:
        session.rollback()
        raise _service_account_http_error(exc) from exc
    audit_from_principal(
        session,
        principal,
        action="service_account.created",
        scope="tenant",
        object_type="service_account",
        object_id=item.id,
        details={
            "name": item.name,
            "scope_ceiling": list(item.scope_ceiling),
        },
    )
    session.commit()
    return _service_account_item(item)


@router.patch(
    "/{service_account_id}",
    response_model=ServiceAccountItem,
)
def update_managed_service_account(
    service_account_id: str,
    payload: ServiceAccountUpdateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(
        require_scope("access:service_account:write")
    ),
):
    tenant = _resolve_tenant(session, principal, None)
    changes = {
        field: getattr(payload, field)
        for field in payload.model_fields_set
        if field != "expected_revision"
    }
    for field in ("name", "scope_ceiling", "is_active"):
        if field in changes and changes[field] is None:
            raise HTTPException(
                status_code=status.HTTP_422_UNPROCESSABLE_CONTENT,
                detail=f"{field} cannot be null",
            )
    try:
        item = update_service_account(
            session,
            tenant_id=tenant.id,
            service_account_id=service_account_id,
            principal=principal,
            expected_revision=payload.expected_revision,
            changes=changes,
        )
    except (ServiceAccountError, PermissionError) as exc:
        session.rollback()
        raise _service_account_http_error(exc) from exc
    audit_from_principal(
        session,
        principal,
        action="service_account.updated",
        scope="tenant",
        object_type="service_account",
        object_id=item.id,
        details={
            "changed_fields": sorted(changes),
            "revision": item.revision,
        },
    )
    session.commit()
    return _service_account_item(item)


@router.post(
    "/{service_account_id}/retire",
    response_model=ServiceAccountItem,
)
def retire_managed_service_account(
    service_account_id: str,
    payload: ServiceAccountRetireRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(
        require_scope("access:service_account:write")
    ),
):
    tenant = _resolve_tenant(session, principal, None)
    try:
        item = retire_service_account(
            session,
            tenant_id=tenant.id,
            service_account_id=service_account_id,
            principal=principal,
            expected_revision=payload.expected_revision,
        )
    except (ServiceAccountError, PermissionError) as exc:
        session.rollback()
        raise _service_account_http_error(exc) from exc
    audit_from_principal(
        session,
        principal,
        action="service_account.retired",
        scope="tenant",
        object_type="service_account",
        object_id=item.id,
        details={"revision": item.revision},
    )
    session.commit()
    return _service_account_item(item)


@router.get(
    "/{service_account_id}/credentials",
    response_model=ServiceAccountCredentialListResponse,
)
def list_managed_service_account_credentials(
    service_account_id: str,
    include_revoked: bool = Query(default=True),
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(
        require_scope("access:service_account:read")
    ),
):
    tenant = _resolve_tenant(session, principal, None)
    try:
        item, credentials = list_service_account_credentials(
            session,
            tenant_id=tenant.id,
            service_account_id=service_account_id,
            include_revoked=include_revoked,
        )
    except ServiceAccountError as exc:
        raise _service_account_http_error(exc) from exc
    return ServiceAccountCredentialListResponse(
        service_account_revision=item.revision,
        items=[_credential_item(credential) for credential in credentials],
    )


@router.post(
    "/{service_account_id}/credentials",
    response_model=ServiceAccountCredentialSecretResponse,
    status_code=status.HTTP_201_CREATED,
)
def create_managed_service_account_credential(
    service_account_id: str,
    payload: ServiceAccountCredentialCreateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(
        require_scope("access:service_account:write")
    ),
):
    tenant = _resolve_tenant(session, principal, None)
    try:
        assert_api_keys_allowed(session, tenant)
        item, created = create_service_account_credential(
            session,
            tenant_id=tenant.id,
            service_account_id=service_account_id,
            principal=principal,
            expected_revision=payload.expected_revision,
            name=payload.name,
            scopes=payload.scopes,
            expires_at=payload.expires_at,
        )
    except (ServiceAccountError, PermissionError, AdminConflictError) as exc:
        session.rollback()
        raise _service_account_http_error(exc) from exc
    audit_from_principal(
        session,
        principal,
        action="service_account.credential_created",
        scope="tenant",
        object_type="service_account_credential",
        object_id=created.model.id,
        details={
            "service_account_id": item.id,
            "prefix": created.model.prefix,
            "scopes": list(created.model.scopes),
            "service_account_revision": item.revision,
        },
    )
    session.commit()
    return ServiceAccountCredentialSecretResponse(
        service_account_revision=item.revision,
        credential=_credential_item(created.model),
        secret=created.secret,
    )


@router.post(
    "/{service_account_id}/credentials/{credential_id}/rotate",
    response_model=ServiceAccountCredentialSecretResponse,
)
def rotate_managed_service_account_credential(
    service_account_id: str,
    credential_id: str,
    payload: ServiceAccountCredentialRotateRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(
        require_scope("access:service_account:write")
    ),
):
    tenant = _resolve_tenant(session, principal, None)
    try:
        assert_api_keys_allowed(session, tenant)
        item, previous, created = rotate_service_account_credential(
            session,
            tenant_id=tenant.id,
            service_account_id=service_account_id,
            credential_id=credential_id,
            principal=principal,
            expected_revision=payload.expected_revision,
            name=payload.name,
            scopes=payload.scopes,
            expires_at=payload.expires_at,
        )
    except (ServiceAccountError, PermissionError, AdminConflictError) as exc:
        session.rollback()
        raise _service_account_http_error(exc) from exc
    audit_from_principal(
        session,
        principal,
        action="service_account.credential_rotated",
        scope="tenant",
        object_type="service_account_credential",
        object_id=created.model.id,
        details={
            "service_account_id": item.id,
            "previous_credential_id": previous.id,
            "prefix": created.model.prefix,
            "scopes": list(created.model.scopes),
            "service_account_revision": item.revision,
        },
    )
    session.commit()
    return ServiceAccountCredentialSecretResponse(
        service_account_revision=item.revision,
        credential=_credential_item(created.model),
        secret=created.secret,
    )


@router.post(
    "/{service_account_id}/credentials/{credential_id}/revoke",
    response_model=ServiceAccountCredentialMutationResponse,
)
def revoke_managed_service_account_credential(
    service_account_id: str,
    credential_id: str,
    payload: ServiceAccountCredentialRevokeRequest,
    session: Session = Depends(get_session),
    principal: ApiPrincipal = Depends(
        require_scope("access:service_account:write")
    ),
):
    tenant = _resolve_tenant(session, principal, None)
    try:
        item, credential = revoke_service_account_credential(
            session,
            tenant_id=tenant.id,
            service_account_id=service_account_id,
            credential_id=credential_id,
            principal=principal,
            expected_revision=payload.expected_revision,
        )
    except (ServiceAccountError, PermissionError) as exc:
        session.rollback()
        raise _service_account_http_error(exc) from exc
    audit_from_principal(
        session,
        principal,
        action="service_account.credential_revoked",
        scope="tenant",
        object_type="service_account_credential",
        object_id=credential.id,
        details={
            "service_account_id": item.id,
            "prefix": credential.prefix,
            "service_account_revision": item.revision,
        },
    )
    session.commit()
    return ServiceAccountCredentialMutationResponse(
        service_account_revision=item.revision,
        credential=_credential_item(credential),
    )


def _service_account_item(
    item: object,
    summary: ServiceAccountCredentialSummary | None = None,
) -> ServiceAccountItem:
    values = ServiceAccountItem.model_validate(
        item, from_attributes=True
    )
    if summary is None:
        return values
    return values.model_copy(
        update={
            "credential_count": summary.credential_count,
            "active_credential_count": summary.active_credential_count,
            "last_credential_used_at": summary.last_credential_used_at,
        }
    )


def _credential_item(item: object) -> ServiceAccountCredentialItem:
    return ServiceAccountCredentialItem.model_validate(
        item,
        from_attributes=True,
    )


def _service_account_http_error(exc: Exception) -> HTTPException:
    if isinstance(exc, ServiceAccountNotFoundError):
        return HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=str(exc),
        )
    if isinstance(exc, ServiceAccountCredentialNotFoundError):
        return HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=str(exc),
        )
    if isinstance(exc, ServiceAccountConflictError):
        return HTTPException(
            status_code=status.HTTP_409_CONFLICT,
            detail=str(exc),
        )
    if isinstance(exc, PermissionError):
        return HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail=str(exc),
        )
    if isinstance(exc, AdminConflictError):
        return HTTPException(
            status_code=status.HTTP_409_CONFLICT,
            detail=str(exc),
        )
    return HTTPException(
        status_code=status.HTTP_422_UNPROCESSABLE_CONTENT,
        detail=str(exc),
    )


__all__ = ["router"]