import os
from typing import Any, Dict, Optional, Tuple

import requests
from flask import Blueprint, jsonify, request

import db


auth_blueprint = Blueprint("auth", __name__)


SUPABASE_URL = os.getenv("SUPABASE_URL")
SUPABASE_ANON_KEY = os.getenv("SUPABASE_ANON_KEY")
SUPABASE_SERVICE_ROLE_KEY = os.getenv("SUPABASE_SERVICE_ROLE_KEY")

if not SUPABASE_URL or not SUPABASE_ANON_KEY or not SUPABASE_SERVICE_ROLE_KEY:
    raise RuntimeError("Supabase credentials (URL, ANON key, service role key) must be configured.")

AUTH_BASE = f"{SUPABASE_URL}/auth/v1"


def _extract_token_from_header() -> Optional[str]:
    auth_header = request.headers.get("Authorization", "")
    if not auth_header.startswith("Bearer "):
        return None
    return auth_header.split(" ", maxsplit=1)[1].strip()


def _fetch_supabase_user(accessToken: str) -> Tuple[Optional[Dict[str, Any]], Optional[Tuple[str, int]]]:
    """Validate the Supabase access token and return the user payload."""
    response = requests.get(
        f"{AUTH_BASE}/user",
        headers={
            "Authorization": f"Bearer {accessToken}",
            "apikey": SUPABASE_ANON_KEY,
        },
        timeout=10,
    )
    if response.status_code != 200:
        return None, ("Invalid Supabase access token.", 401)
    return response.json(), None


def verify_request_token() -> Tuple[Optional[Dict[str, Any]], Optional[Tuple[str, int]]]:
    token = _extract_token_from_header()
    if not token:
        return None, ("Authorization header missing or invalid.", 401)
    return _fetch_supabase_user(token)


@auth_blueprint.route("/session", methods=["GET"])
def session_info():
    """Return the Supabase-authenticated user profile."""
    user_payload, error = verify_request_token()
    if error:
        message, status = error
        return jsonify({"error": message}), status

    user_id = user_payload.get("id")
    profile = db.get_user_profile(user_id)
    return jsonify({"user": user_payload, "profile": profile})