"""
SQLite Database Setup for Telegram Bot

Delegates to shared/database/app_db.py for unified database.
All tables (telegram, trusted devices, backup codes) live in app.db.
"""

import aiosqlite
import logging
from datetime import datetime, timedelta

from shared.database.app_db import DB_PATH, get_db as _get_app_db, init_app_db

logger = logging.getLogger(__name__)

# Re-export DB_PATH for backward compatibility (operations.py imports it)
__all__ = [
    'get_db_connection',
    'init_database',
    'cleanup_expired_codes',
    'cleanup_expired_sessions',
    'cleanup_expired_email_codes',
    'get_database_stats',
    'DB_PATH',
]


async def get_db_connection() -> aiosqlite.Connection:
    """
    Get a database connection. Delegates to shared app_db.

    Returns:
        aiosqlite.Connection: Database connection
    """
    return await _get_app_db()


async def init_database() -> None:
    """
    Initialize the database. Delegates to shared init_app_db().
    Safe to call multiple times - only creates tables if they don't exist.
    """
    await init_app_db()
    logger.info("Database initialized successfully (delegated to app_db)")


async def cleanup_expired_codes() -> int:
    """
    Delete expired authentication codes from the database.

    Returns:
        int: Number of expired codes deleted
    """
    try:
        async with aiosqlite.connect(DB_PATH) as db:
            db.row_factory = aiosqlite.Row
            cursor = await db.execute("""
                DELETE FROM telegram_auth_codes
                WHERE expires_at < ?
            """, (datetime.now(),))

            await db.commit()
            deleted = cursor.rowcount

            if deleted > 0:
                logger.info(f"Cleaned up {deleted} expired auth codes")

            return deleted

    except Exception as e:
        logger.error(f"Failed to cleanup expired codes: {e}")
        return 0


async def cleanup_expired_sessions() -> int:
    """
    Delete expired sessions from the database.

    Returns:
        int: Number of expired sessions deleted
    """
    try:
        async with aiosqlite.connect(DB_PATH) as db:
            db.row_factory = aiosqlite.Row
            cursor = await db.execute("""
                DELETE FROM telegram_sessions
                WHERE expires_at < ?
            """, (datetime.now(),))

            await db.commit()
            deleted = cursor.rowcount

            if deleted > 0:
                logger.info(f"Cleaned up {deleted} expired sessions")

            return deleted

    except Exception as e:
        logger.error(f"Failed to cleanup expired sessions: {e}")
        return 0


async def cleanup_expired_email_codes() -> int:
    """
    Delete expired and old used email codes from the database.

    Returns:
        int: Number of email codes deleted
    """
    try:
        async with aiosqlite.connect(DB_PATH) as db:
            db.row_factory = aiosqlite.Row
            cursor = await db.execute("""
                DELETE FROM email_auth_codes
                WHERE expires_at < ?
                   OR (used = 1 AND used_at < ?)
            """, (
                datetime.now(),
                datetime.now() - timedelta(days=1)
            ))

            await db.commit()
            deleted = cursor.rowcount

            if deleted > 0:
                logger.info(f"Cleaned up {deleted} expired/old email auth codes")

            return deleted

    except Exception as e:
        logger.error(f"Failed to cleanup email codes: {e}")
        return 0


async def get_database_stats() -> dict:
    """
    Get database statistics for monitoring.

    Returns:
        dict: Database statistics
    """
    try:
        async with aiosqlite.connect(DB_PATH) as db:
            db.row_factory = aiosqlite.Row
            stats = {}

            # Count users
            cursor = await db.execute("SELECT COUNT(*) FROM telegram_users")
            stats['total_users'] = (await cursor.fetchone())[0]

            cursor = await db.execute(
                "SELECT COUNT(*) FROM telegram_users WHERE is_active = 1"
            )
            stats['active_users'] = (await cursor.fetchone())[0]

            # Count pending codes
            cursor = await db.execute("""
                SELECT COUNT(*) FROM telegram_auth_codes
                WHERE used = 0 AND expires_at > ?
            """, (datetime.now(),))
            stats['pending_codes'] = (await cursor.fetchone())[0]

            # Count active sessions
            cursor = await db.execute("""
                SELECT COUNT(*) FROM telegram_sessions
                WHERE expires_at > ?
            """, (datetime.now(),))
            stats['active_sessions'] = (await cursor.fetchone())[0]

            # Database file size
            if DB_PATH.exists():
                stats['db_size_mb'] = DB_PATH.stat().st_size / (1024 * 1024)
            else:
                stats['db_size_mb'] = 0

            return stats

    except Exception as e:
        logger.error(f"Failed to get database stats: {e}")
        return {}