from __future__ import annotations

import os
from pathlib import Path
from typing import Any

import yaml
from fastapi import Depends, FastAPI, Header, HTTPException, Query, Request
from fastapi.responses import JSONResponse, Response

from reuse_surface.hub.compose import compose_from_store, DEFAULT_DOMAIN
from reuse_surface.hub.store import HubStore

HUB_VERSION = "0.1.0"


def _db_path() -> Path:
    return Path(os.environ.get("REUSE_SURFACE_DB", "/data/reuse.db"))


def _cache_dir() -> Path:
    return Path(os.environ.get("REUSE_SURFACE_CACHE_DIR", "/data/cache"))


def _write_token() -> str:
    return os.environ.get("REUSE_SURFACE_TOKEN", "")


def _store() -> HubStore:
    return HubStore(_db_path())


def _http_error(status: int, error: str, message: str) -> HTTPException:
    return HTTPException(
        status_code=status,
        detail={"error": error, "message": message, "details": []},
    )


def _require_auth(authorization: str | None = Header(default=None)) -> None:
    write_token = _write_token()
    if not write_token:
        raise _http_error(
            503, "misconfigured", "REUSE_SURFACE_TOKEN is not configured"
        )
    if not authorization or not authorization.startswith("Bearer "):
        raise _http_error(401, "unauthorized", "Bearer token required")
    token = authorization.removeprefix("Bearer ").strip()
    if token != write_token:
        raise _http_error(401, "unauthorized", "Invalid token")


def create_app() -> FastAPI:
    app = FastAPI(title="reuse-surface federation hub", version=HUB_VERSION)
    store = _store()

    @app.get("/health")
    def health() -> dict[str, str]:
        return {"status": "ok", "service": "reuse-surface", "version": HUB_VERSION}

    @app.get("/v1/repos")
    def list_repos() -> dict[str, Any]:
        repos = store.list_repos()
        return {"count": len(repos), "repos": repos}

    @app.post("/v1/repos", status_code=201, dependencies=[Depends(_require_auth)])
    async def register_repo(request: Request) -> dict[str, Any]:
        payload = await request.json()
        try:
            return store.create_repo(payload)
        except FileExistsError as exc:
            raise _http_error(409, "conflict", str(exc)) from exc
        except ValueError as exc:
            raise _http_error(400, "validation_error", str(exc)) from exc

    @app.get("/v1/repos/{repo}")
    def get_repo(repo: str) -> dict[str, Any]:
        registration = store.get_repo(repo)
        if registration is None:
            raise _http_error(404, "not_found", f"repo not found: {repo}")
        return registration

    @app.patch("/v1/repos/{repo}", dependencies=[Depends(_require_auth)])
    async def update_repo(repo: str, request: Request) -> dict[str, Any]:
        payload = await request.json()
        try:
            return store.update_repo(repo, payload)
        except KeyError as exc:
            raise _http_error(404, "not_found", str(exc)) from exc
        except ValueError as exc:
            raise _http_error(400, "validation_error", str(exc)) from exc

    @app.delete("/v1/repos/{repo}", status_code=204, dependencies=[Depends(_require_auth)])
    def delete_repo(repo: str) -> Response:
        if not store.delete_repo(repo):
            raise _http_error(404, "not_found", f"repo not found: {repo}")
        return Response(status_code=204)

    def _federated_response(
        refresh: bool,
        accept: str | None,
        format_param: str,
    ) -> Response:
        try:
            federated, warnings = compose_from_store(
                store, refresh=refresh, cache_dir=_cache_dir(), domain=DEFAULT_DOMAIN
            )
        except FileNotFoundError as exc:
            raise _http_error(502, "compose_error", str(exc)) from exc

        use_yaml = format_param == "yaml" or (accept and "yaml" in accept.lower())
        headers: dict[str, str] = {}
        if warnings:
            headers["X-Federation-Warnings"] = "; ".join(warnings)
        if use_yaml:
            body = yaml.safe_dump(federated, sort_keys=False)
            return Response(content=body, media_type="application/yaml", headers=headers)
        return JSONResponse(content=federated, headers=headers)

    @app.get("/v1/federated", response_model=None)
    def get_federated(
        request: Request,
        refresh: bool = Query(default=False),
        format: str = Query(default="json"),
    ) -> Response:
        return _federated_response(refresh, request.headers.get("accept"), format)

    @app.post("/v1/federated/compose", response_model=None, dependencies=[Depends(_require_auth)])
    def compose_federated(
        request: Request,
        format: str = Query(default="json"),
    ) -> Response:
        return _federated_response(True, request.headers.get("accept"), format)

    return app


def main() -> None:
    import uvicorn

    host = os.environ.get("REUSE_SURFACE_LISTEN_HOST", "0.0.0.0")
    port = int(os.environ.get("REUSE_SURFACE_LISTEN_PORT", "8000"))
    uvicorn.run(create_app(), host=host, port=port, reload=False)