"""
Auth Service — JWT + Supabase Auth
Works in demo mode (no Supabase) with a simple in-memory user store
"""
import logging
import os
from datetime import datetime, timedelta, timezone
from typing import Optional

import jwt

logger = logging.getLogger(__name__)

JWT_SECRET       = os.getenv("JWT_SECRET", "qs-dev-secret-change-in-prod-32c")
JWT_EXPIRES_MINS = int(os.getenv("JWT_EXPIRES_MINUTES", "60"))

_supabase = None

# Demo user store (only used if Supabase not configured)
_demo_users: dict = {}


def init_supabase():
    global _supabase
    url = os.getenv("SUPABASE_URL")
    key = os.getenv("SUPABASE_SERVICE_KEY")
    if url and key:
        try:
            from supabase import create_client
            _supabase = create_client(url, key)
            logger.info("Auth service: Supabase connected")
        except Exception as e:
            logger.warning(f"Auth Supabase init failed: {e} — using demo mode")
    else:
        logger.info("Auth service: No Supabase config — demo mode")


def make_jwt(user_id: str, email: str, role: str = "reader") -> str:
    payload = {
        "sub":   user_id,
        "email": email,
        "role":  role,
        "iat":   datetime.now(timezone.utc),
        "exp":   datetime.now(timezone.utc) + timedelta(minutes=JWT_EXPIRES_MINS),
    }
    return jwt.encode(payload, JWT_SECRET, algorithm="HS256")


def verify_jwt(token: str) -> Optional[dict]:
    try:
        return jwt.decode(token, JWT_SECRET, algorithms=["HS256"])
    except jwt.ExpiredSignatureError:
        raise ValueError("Token expired")
    except jwt.InvalidTokenError:
        raise ValueError("Invalid token")


def register(email: str, password: str, full_name: str) -> dict:
    """Register user — Supabase if configured, else demo store"""
    if _supabase:
        from gotrue.errors import AuthApiError
        try:
            r = _supabase.auth.sign_up({
                "email": email, "password": password,
                "options": {"data": {"full_name": full_name}},
            })
            if not r.user:
                raise ValueError("Registration failed")
            user = r.user
            role  = get_user_role(user.id)
            token = make_jwt(user.id, user.email, role)
            # Ensure user_profiles row exists (FR-04)
            try:
                _supabase.table("user_profiles").insert({"id": user.id, "role": "reader"}).execute()
            except Exception:
                pass
            return {"access_token": token, "expires_in": JWT_EXPIRES_MINS * 60,
                    "user": {"id": user.id, "email": user.email, "full_name": full_name, "role": role}}
        except AuthApiError as e:
            raise ValueError(str(e.message))

    # Demo mode
    if email in _demo_users:
        raise ValueError("Email already registered")
    import uuid, hashlib
    uid  = str(uuid.uuid4())
    _demo_users[email] = {"id": uid, "password": hashlib.sha256(password.encode()).hexdigest(),
                           "full_name": full_name, "role": "writer"}
    token = make_jwt(uid, email, "writer")
    return {"access_token": token, "expires_in": JWT_EXPIRES_MINS * 60,
            "user": {"id": uid, "email": email, "full_name": full_name, "role": "writer"}}


def login(email: str, password: str) -> dict:
    """Login — Supabase if configured, else demo store"""
    if _supabase:
        from gotrue.errors import AuthApiError
        try:
            r = _supabase.auth.sign_in_with_password({"email": email, "password": password})
            if not r.user:
                raise ValueError("Invalid credentials")
            user = r.user
            role  = get_user_role(user.id)
            meta  = user.user_metadata or {}
            token = make_jwt(user.id, user.email, role)
            # Lazy profile creation for users registered before F04 (FR-04)
            try:
                existing = _supabase.table("user_profiles").select("id").eq("id", user.id).limit(1).execute()
                if not existing.data:
                    _supabase.table("user_profiles").insert({"id": user.id, "role": "reader"}).execute()
            except Exception:
                pass
            return {"access_token": token, "expires_in": JWT_EXPIRES_MINS * 60,
                    "user": {"id": user.id, "email": user.email,
                             "full_name": meta.get("full_name", ""), "role": role}}
        except AuthApiError:
            raise ValueError("Invalid email or password")

    # Demo mode
    import hashlib
    u = _demo_users.get(email)
    if not u or u["password"] != hashlib.sha256(password.encode()).hexdigest():
        raise ValueError("Invalid email or password")
    token = make_jwt(u["id"], email, u["role"])
    return {"access_token": token, "expires_in": JWT_EXPIRES_MINS * 60,
            "user": {"id": u["id"], "email": email, "full_name": u["full_name"], "role": u["role"]}}


def send_reset_email(email: str):
    if _supabase:
        try:
            _supabase.auth.reset_password_email(email)
        except Exception:
            pass


def get_user_role(user_id: str) -> str:
    if not _supabase:
        return "writer"  # demo mode: trust all logged-in users
    try:
        r = _supabase.table("user_profiles").select("role").eq("id", user_id).single().execute()
        return (r.data or {}).get("role", "reader")
    except Exception:
        return "reader"