"""Upload preflight, batch, and verification API (US05-01, US05-02, US05-04).

Preflight is a command, not a resource read: it contacts the Immich server, hashes
the current bytes, and issues a token. Creating a batch requires that token, and
starting one enqueues a durable job on the single ``upload`` lane — the API never
runs the uploader in the request thread.

``verify`` and ``resolve`` are the way out of an uncertain outcome; ``start``
refuses one with ``409`` rather than letting the browser retry it.
"""

from __future__ import annotations

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

from photo_pipeline.jobs.domain_handlers import UPLOAD_BATCH, UPLOAD_LOCK
from photo_pipeline.services.jobs import JobBlocked, JobService
from photo_pipeline.services.upload_batches import (
    BatchConflict,
    BatchError,
    UploadBatchService,
)
from photo_pipeline.services.upload_verification import (
    UploadVerificationService,
    VerificationError,
    retry_blockers,
)
from photo_pipeline.services.uploads import UploadError, UploadService

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


class PreflightRequest(BaseModel):
    # ``None`` means every album; an explicit list scopes the check.
    albums: list[str] | None = None
    # Approving a partial upload is an explicit act, never a default.
    allow_partial: bool = False


class CreateBatchRequest(PreflightRequest):
    # The token of the preflight the user approved; a stale one is refused.
    token: str


class ResolveRequest(BaseModel):
    asset_id: str
    # uploaded | upgraded | duplicate | skipped | failed | unknown
    outcome: str
    # What the operator actually checked, and who they are — both mandatory so a
    # manual resolution can never look like server evidence.
    evidence: str
    actor: str


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


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


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


def _error(status: int, code: str, message: str) -> JSONResponse:
    return JSONResponse(status_code=status, content={"error": {"code": code, "message": message}})


@router.post("/upload-preflight")
def preflight(request: Request, body: PreflightRequest | None = None):
    body = body or PreflightRequest()
    try:
        return _service(request).preflight(body.albums, allow_partial=body.allow_partial)
    except UploadError as error:
        return _error(422, "unknown_album", str(error))


@router.post("/upload-batches", status_code=201)
def create_batches(body: CreateBatchRequest, request: Request):
    """Turn an approved preflight into one durable batch per album."""
    try:
        return {
            "batches": _batches(request).create(
                body.albums, token=body.token, allow_partial=body.allow_partial
            )
        }
    except UploadError as error:
        return _error(422, "unknown_album", str(error))
    except BatchConflict as error:
        return _error(409, error.code, str(error))
    except BatchError as error:
        return _error(422, error.code, str(error))


@router.get("/upload-batches")
def list_batches(request: Request) -> dict:
    return {"batches": _batches(request).list()}


@router.get("/upload-batches/{batch_id}")
def get_batch(batch_id: str, request: Request):
    batch = _batches(request).get(batch_id)
    if batch is None:
        return _error(404, "not_found", f"unknown upload batch {batch_id}")
    return batch


@router.post("/upload-batches/{batch_id}/start")
def start_batch(batch_id: str, request: Request):
    """Queue the batch on the uploader lane. The worker performs the upload."""
    service = _batches(request)
    batch = service.get(batch_id)
    if batch is None:
        return _error(404, "not_found", f"unknown upload batch {batch_id}")
    # An uncertain outcome or bytes changed after upload must be resolved first
    # (US05-04); the worker refuses them too, but the user is told here.
    blocked = retry_blockers(batch)
    if blocked:
        return _error(409, blocked[0]["code"], blocked[0]["message"])
    try:
        job = JobService(request.app.state.session_factory).enqueue(
            UPLOAD_BATCH,
            lock=UPLOAD_LOCK,
            # One queued attempt per batch attempt: a double-clicked start reuses it.
            idempotency_key=f"upload:{batch_id}:{batch['attempt_count']}",
            items=[batch_id],
        )
    except JobBlocked as error:
        return _error(409, error.code, str(error))
    return {"batch_id": batch_id, "job": job}


@router.post("/upload-batches/{batch_id}/verify")
def verify_batch(batch_id: str, request: Request):
    """Check the batch against Immich and the bytes on disk (US05-04)."""
    try:
        return _verification(request).verify(batch_id)
    except VerificationError as error:
        return _error(404 if error.code == "not_found" else 422, error.code, str(error))


@router.post("/upload-batches/{batch_id}/resolve")
def resolve_item(batch_id: str, body: ResolveRequest, request: Request):
    """Record an operator's own verification of one item. Evidence is mandatory."""
    try:
        return _verification(request).resolve(
            batch_id,
            body.asset_id,
            outcome=body.outcome,
            evidence=body.evidence,
            actor=body.actor,
        )
    except VerificationError as error:
        return _error(404 if error.code == "not_found" else 422, error.code, str(error))


@router.get("/upload-batches/{batch_id}/verifications")
def list_verifications(batch_id: str, request: Request):
    batch = _batches(request).get(batch_id)
    if batch is None:
        return _error(404, "not_found", f"unknown upload batch {batch_id}")
    return {"verifications": _verification(request).history(batch_id)}


@router.post("/upload-batches/{batch_id}/cancel")
def cancel_batch(batch_id: str, request: Request):
    try:
        return _batches(request).cancel(batch_id)
    except BatchError as error:
        return _error(404 if error.code == "not_found" else 409, error.code, str(error))