from __future__ import annotations

import asyncio
from contextlib import asynccontextmanager
from typing import Any

from fastapi import FastAPI, File, Form, HTTPException, Request, UploadFile

from hf_backend.config import load_config
from hf_backend.fetcher import FetchError
from hf_backend.hub_store import HubStore
from hf_backend.service import QueueProcessor


def _require_shared_token(request: Request, shared_token: str) -> None:
    auth_header = request.headers.get("Authorization", "")
    expected = f"Bearer {shared_token}"
    if auth_header != expected:
        raise HTTPException(status_code=401, detail="unauthorized")


def create_app(*, config=None, store=None, processor=None) -> FastAPI:
    runtime_config = config or load_config()
    runtime_store = store
    if runtime_store is None and processor is None:
        runtime_store = HubStore(runtime_config)
    runtime_processor = processor or QueueProcessor(runtime_config, runtime_store)

    @asynccontextmanager
    async def lifespan(_app: FastAPI):
        if processor is not None:
            yield
            return
        assert runtime_store is not None
        runtime_store.ensure_dataset_repo()
        manifest = runtime_store.load_manifest()
        runtime_store.save_manifest(manifest, message="Initialize manifest")
        yield

    app = FastAPI(title="ebook-hf-executor", lifespan=lifespan)

    @app.get("/health")
    def health() -> dict[str, Any]:
        manifest = runtime_processor.current_manifest()
        return {
            "ok": True,
            "dataset_repo_id": getattr(runtime_config, "dataset_repo_id", ""),
            "busy": runtime_processor.is_running(),
            "pending_jobs": sum(1 for job in manifest["jobs"] if job.get("status") == "pending"),
        }

    @app.post("/api/upload")
    async def upload_job(
        request: Request,
        file: UploadFile = File(...),
        language: str | None = Form(None),
        model: str | None = Form(None),
    ) -> dict[str, Any]:
        _require_shared_token(request, runtime_config.shared_token)
        if not file.filename:
            raise HTTPException(status_code=400, detail="missing file name")

        content = await file.read()
        if not content:
            raise HTTPException(status_code=400, detail="empty file")

        job = runtime_processor.submit_upload(
            filename=file.filename,
            content=content,
            language=language,
            model=model,
            origin="upload",
        )
        return {"ok": True, "job": job}

    @app.post("/api/fetch-book")
    async def fetch_book(request: Request) -> dict[str, Any]:
        _require_shared_token(request, runtime_config.shared_token)
        payload = await request.json() if request.headers.get("content-type", "").startswith("application/json") else {}
        payload = payload if isinstance(payload, dict) else {}
        query = str(payload.get("query") or "").strip()
        if not query:
            raise HTTPException(status_code=400, detail="missing query")

        try:
            job = await asyncio.to_thread(runtime_processor.submit_fetch, query=query)
        except FetchError as exc:
            raise HTTPException(status_code=404, detail=str(exc))
        started = runtime_processor.trigger_background_run()
        return {"ok": True, "started": started, "job": job}

    @app.post("/api/run-once")
    def run_once(request: Request) -> dict[str, Any]:
        _require_shared_token(request, runtime_config.shared_token)
        started = runtime_processor.trigger_background_run()
        return {"ok": True, "started": started}

    @app.post("/api/download-weekly")
    def download_weekly(request: Request) -> dict[str, Any]:
        _require_shared_token(request, runtime_config.shared_token)
        job = runtime_processor.submit_weekly_download()
        return {"ok": True, "job": job}

    return app


try:
    app = create_app()
except Exception:
    app = FastAPI(title="ebook-hf-executor")

    @app.get("/health")
    def health_unconfigured() -> dict[str, Any]:
        return {
            "ok": False,
            "error": "service is not configured yet",
            "pending_jobs": 0,
        }