from __future__ import annotations

from urllib.parse import quote
import uuid

from sqlalchemy.orm import Session

from govoplan_core.core.institutional import (
    GovernedContextEnvelope,
    InstitutionalReference,
    TemporalRevision,
)
from govoplan_core.core.tickets import (
    TicketCaseEscalationCommand,
    TicketCaseEscalationResult,
)
from govoplan_core.security.module_permissions import scopes_grant_compatible
from govoplan_cases.backend.domain import CaseRecord
from govoplan_cases.backend.service import create_case, get_case, list_case_catalog


_CASE_NAMESPACE = uuid.uuid5(
    uuid.NAMESPACE_URL,
    "https://govoplan.add-ideas.de/contracts/tickets/case-escalation/v1",
)


class TicketCaseEscalationProvider:
    """Create one replay-safe formal Case while keeping Ticket history separate."""

    def escalate_ticket(
        self,
        session: object,
        principal: object,
        *,
        command: TicketCaseEscalationCommand,
    ) -> TicketCaseEscalationResult:
        db = _session(session)
        tenant_id = str(getattr(principal, "tenant_id", "") or "").strip()
        if command.tenant_id != tenant_id:
            raise PermissionError("Ticket escalation cannot cross tenants.")
        if not _has_scope(principal, "cases:case:create"):
            raise PermissionError("Ticket escalation requires cases:case:create.")
        case_id = str(
            uuid.uuid5(
                _CASE_NAMESPACE,
                "\0".join((tenant_id, command.ticket_id, command.idempotency_key)),
            )
        )
        existing = get_case(db, principal, case_id=case_id)
        if existing is not None:
            return _result(existing, replayed=True)

        catalog = list_case_catalog(db, principal)
        case_type = next(
            (
                item
                for item in catalog["types"]
                if item.get("type_key") == command.case_type_key and item.get("active")
            ),
            None,
        )
        if case_type is None:
            raise ValueError(
                f"Case type {command.case_type_key!r} is not configured or active."
            )
        case_ref = InstitutionalReference(
            kind="case",
            owner_module="cases",
            object_id=case_id,
            tenant_id=tenant_id,
            version="1",
            valid_at=command.occurred_at,
        )
        ticket_ref = InstitutionalReference(
            kind="work_item",
            owner_module="tickets",
            object_id=command.ticket_id,
            tenant_id=tenant_id,
            version=str(command.metadata.get("ticket_revision") or "1"),
            valid_at=command.occurred_at,
            label=command.ticket_number,
        )
        change_reason = f"Escalated from ticket {command.ticket_number}."
        context = GovernedContextEnvelope(
            tenant_id=tenant_id,
            temporal=TemporalRevision(
                revision="1",
                valid_from=command.occurred_at,
                recorded_at=command.occurred_at,
                change_reason=change_reason,
            ),
            case_ref=case_ref,
            work_item_ref=ticket_ref,
        )
        record = CaseRecord(
            reference=case_ref,
            case_number=_case_number(command, case_id),
            case_type_key=command.case_type_key,
            status_key=str(case_type["initial_status_key"]),
            title=command.title,
            context=context,
            opened_at=command.occurred_at,
            recorded_at=command.occurred_at,
            change_reason=change_reason,
            metadata={
                "source_module": "tickets",
                "source_resource_type": "ticket",
                "source_resource_id": command.ticket_id,
                "source_resource_number": command.ticket_number,
                "source_revision": str(command.metadata.get("ticket_revision") or "1"),
                "handoff_note": command.handoff_note,
                "integration_contract": "tickets.case_escalation/v1",
            },
        )
        created = create_case(
            db,
            principal,
            record=record,
            idempotency_key=f"ticket-escalation:{command.idempotency_key}",
        )
        return _result(created, replayed=False)


def _result(record: CaseRecord, *, replayed: bool) -> TicketCaseEscalationResult:
    return TicketCaseEscalationResult(
        provider_id="cases",
        case_id=record.reference.object_id,
        case_number=record.case_number,
        case_url=f"/cases/{quote(record.reference.object_id, safe='')}",
        replayed=replayed,
        metadata={
            "case_revision": record.revision,
            "case_type_key": record.case_type_key,
            "status_key": record.status_key,
        },
    )


def _case_number(command: TicketCaseEscalationCommand, case_id: str) -> str:
    prefix = f"CASE-{command.ticket_number}"[:230].rstrip("-")
    return f"{prefix}-{case_id[:8].upper()}"


def _has_scope(principal: object, scope: str) -> bool:
    method = getattr(principal, "has", None)
    if callable(method):
        return bool(method(scope))
    return scopes_grant_compatible(
        frozenset(getattr(principal, "scopes", ()) or ()),
        scope,
    )


def _session(value: object) -> Session:
    if not isinstance(value, Session):
        raise TypeError("Ticket Case escalation requires a SQLAlchemy session.")
    return value


__all__ = ["TicketCaseEscalationProvider"]