"""Archive location and preflight API (US06-01).

Registering a location writes a marker onto the medium; preflight is a command
rather than a read, because it probes the destination, hashes the scope, and issues
the token a later archive plan must present (US06-02). Neither endpoint moves or
removes a single library file.
"""

from __future__ import annotations

from fastapi import APIRouter, Request
from fastapi.responses import JSONResponse
from pydantic import BaseModel

from photo_pipeline.services.archives import ArchiveError, ArchiveService

router = APIRouter(tags=["archives"])

# Which failures are the caller's request (422) and which are a missing thing (404).
NOT_FOUND_CODES = {"unknown_location"}


class RegisterLocationRequest(BaseModel):
    name: str
    root: str


class PreflightRequest(BaseModel):
    location_id: str
    # ``None`` means every album; an explicit list scopes the check.
    albums: list[str] | None = None


def _service(request: Request) -> ArchiveService:
    return ArchiveService(request.app.state.session_factory, config=request.app.state.config)


def _error(error: ArchiveError) -> JSONResponse:
    status = 404 if error.code in NOT_FOUND_CODES else 422
    return JSONResponse(
        status_code=status, content={"error": {"code": error.code, "message": str(error)}}
    )


@router.post("/archive-locations", status_code=201)
def register_location(body: RegisterLocationRequest, request: Request):
    try:
        return _service(request).register(body.name, body.root)
    except ArchiveError as error:
        return _error(error)


@router.get("/archive-locations")
def list_locations(request: Request) -> dict:
    return {"locations": _service(request).locations()}


@router.post("/archive-preflight")
def preflight(body: PreflightRequest, request: Request):
    try:
        return _service(request).preflight(body.location_id, body.albums)
    except ArchiveError as error:
        return _error(error)