"""FlowDeck — Session management with signed cookies."""
from __future__ import annotations

import json
from datetime import datetime, timedelta

from itsdangerous import URLSafeTimedSerializer, BadSignature, SignatureExpired

from app.config import settings

_serializer = URLSafeTimedSerializer(settings.app_secret_key)


class SessionManager:
    """Manages user sessions via signed cookies."""

    @staticmethod
    def create_session(user_data: dict) -> str:
        """Create a signed session cookie value."""
        payload = {
            "user": user_data,
            "created_at": datetime.utcnow().isoformat(),
        }
        return _serializer.dumps(payload)

    @staticmethod
    def decode_session(cookie: str) -> dict | None:
        """Decode and validate a session cookie. Returns user data or None."""
        try:
            payload = _serializer.loads(cookie, max_age=86400 * 7)  # 7 days
            return payload.get("user")
        except (BadSignature, SignatureExpired):
            return None

    @staticmethod
    def store_token(user_id: int, gitea_token: str) -> None:
        """Store a user's Gitea OAuth token in SQLite."""
        from app.db import get_conn
        with get_conn() as conn:
            conn.execute(
                """INSERT INTO user_tokens (gitea_user_id, gitea_token, updated_at)
                   VALUES (?, ?, CURRENT_TIMESTAMP)
                   ON CONFLICT(gitea_user_id)
                   DO UPDATE SET gitea_token=excluded.gitea_token, updated_at=CURRENT_TIMESTAMP""",
                (user_id, gitea_token),
            )
            conn.commit()

    @staticmethod
    def get_token(user_id: int) -> str | None:
        """Get a user's stored Gitea token."""
        from app.db import get_conn
        with get_conn() as conn:
            row = conn.execute(
                "SELECT gitea_token FROM user_tokens WHERE gitea_user_id=?",
                (user_id,),
            ).fetchone()
        return row["gitea_token"] if row else None


# FastAPI dependency
async def get_current_user(request) -> dict | None:
    """FastAPI dependency: extract current user from session cookie."""
    from fastapi import Request
    session = request.cookies.get("flowdeck_session")
    if session:
        return SessionManager.decode_session(session)
    return None