"""HTTP routes for the planning engine.

Routers stay thin: validate via Pydantic, call the service, map domain errors
to HTTP. All allocation logic lives in `app.services.allocation_service`, and
all bulk-apply logic (idempotency, collisions, `replace`, validation) lives in
`app.services.planning_service.PlanningService.apply_proposed_days`. See
PLANNING_ENGINE_SPEC.md §4.
"""

from fastapi import APIRouter, HTTPException, status

from app.dependencies import PlanningEngineServiceDep, PlanningServiceDep
from app.models.plan import (
    PlanApplyRequest,
    PlanApplyResponse,
    PlanProposalResponse,
    PlanProposeRequest,
)
from app.utils.errors import NotFoundError, ValidationError

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


@router.post("/propose", response_model=PlanProposalResponse)
async def propose_plan(
    payload: PlanProposeRequest, service: PlanningEngineServiceDep
) -> PlanProposalResponse:
    """Compute a plan proposal. Read-only — persists nothing, safe to spam."""
    try:
        proposal = await service.propose(payload.workspace_id)
    except NotFoundError as exc:
        raise HTTPException(status.HTTP_404_NOT_FOUND, str(exc)) from exc
    except ValidationError as exc:
        raise HTTPException(status.HTTP_422_UNPROCESSABLE_ENTITY, str(exc)) from exc
    return PlanProposalResponse.from_domain(proposal)


@router.post("/apply", response_model=PlanApplyResponse)
async def apply_plan(payload: PlanApplyRequest, service: PlanningServiceDep) -> PlanApplyResponse:
    """Accept a (possibly user-edited) set of proposed days as real plan.

    Always returns 200 with `accepted: false` and a `rejections`/`collisions`
    breakdown when the batch is refused — refusal (a collision without
    `replace`, an invalid day type, a balance/eligibility violation) is an
    expected, structured outcome for the UI to render, not an HTTP error.
    A genuinely missing workspace/child (404) is the one case still raised
    as an HTTP error, since that's not something the batch report can explain.
    """
    try:
        result = await service.apply_proposed_days(
            workspace_id=payload.workspace_id,
            days=[item.to_domain() for item in payload.days],
            replace=payload.replace,
        )
    except NotFoundError as exc:
        raise HTTPException(status.HTTP_404_NOT_FOUND, str(exc)) from exc
    return PlanApplyResponse.from_domain(result)