"""
数据库清理服务 - 清理过期的验证码和会话
"""

from __future__ import annotations

from datetime import UTC, datetime, timedelta

from app.database.email_verification import EmailVerification, LoginSession
from app.log import logger

from sqlmodel import col, select
from sqlmodel.ext.asyncio.session import AsyncSession


class DatabaseCleanupService:
    """数据库清理服务"""

    @staticmethod
    async def cleanup_expired_verification_codes(db: AsyncSession) -> int:
        """
        清理过期的邮件验证码

        Args:
            db: 数据库会话

        Returns:
            int: 清理的记录数
        """
        try:
            # 查找过期的验证码记录
            current_time = datetime.now(UTC)

            stmt = select(EmailVerification).where(EmailVerification.expires_at < current_time)
            result = await db.exec(stmt)
            expired_codes = result.all()

            # 删除过期的记录
            deleted_count = 0
            for code in expired_codes:
                await db.delete(code)
                deleted_count += 1

            await db.commit()

            if deleted_count > 0:
                logger.debug(f"[Cleanup Service] Cleaned up {deleted_count} expired email verification codes")

            return deleted_count

        except Exception as e:
            await db.rollback()
            logger.error(f"[Cleanup Service] Error cleaning expired verification codes: {e!s}")
            return 0

    @staticmethod
    async def cleanup_expired_login_sessions(db: AsyncSession) -> int:
        """
        清理过期的登录会话

        Args:
            db: 数据库会话

        Returns:
            int: 清理的记录数
        """
        try:
            # 查找过期的登录会话记录
            current_time = datetime.now(UTC)

            stmt = select(LoginSession).where(LoginSession.expires_at < current_time)
            result = await db.exec(stmt)
            expired_sessions = result.all()

            # 删除过期的记录
            deleted_count = 0
            for session in expired_sessions:
                await db.delete(session)
                deleted_count += 1

            await db.commit()

            if deleted_count > 0:
                logger.debug(f"[Cleanup Service] Cleaned up {deleted_count} expired login sessions")

            return deleted_count

        except Exception as e:
            await db.rollback()
            logger.error(f"[Cleanup Service] Error cleaning expired login sessions: {e!s}")
            return 0

    @staticmethod
    async def cleanup_old_used_verification_codes(db: AsyncSession, days_old: int = 7) -> int:
        """
        清理旧的已使用验证码记录

        Args:
            db: 数据库会话
            days_old: 清理多少天前的已使用记录，默认7天

        Returns:
            int: 清理的记录数
        """
        try:
            # 查找指定天数前的已使用验证码记录
            cutoff_time = datetime.now(UTC) - timedelta(days=days_old)

            stmt = select(EmailVerification).where(col(EmailVerification.is_used).is_(True))
            result = await db.exec(stmt)
            all_used_codes = result.all()

            # 筛选出过期的记录
            old_used_codes = [code for code in all_used_codes if code.used_at and code.used_at < cutoff_time]

            # 删除旧的已使用记录
            deleted_count = 0
            for code in old_used_codes:
                await db.delete(code)
                deleted_count += 1

            await db.commit()

            if deleted_count > 0:
                logger.debug(
                    f"[Cleanup Service] Cleaned up {deleted_count} used verification codes older than {days_old} days"
                )

            return deleted_count

        except Exception as e:
            await db.rollback()
            logger.error(f"[Cleanup Service] Error cleaning old used verification codes: {e!s}")
            return 0

    @staticmethod
    async def cleanup_old_verified_sessions(db: AsyncSession, days_old: int = 30) -> int:
        """
        清理旧的已验证会话记录

        Args:
            db: 数据库会话
            days_old: 清理多少天前的已验证记录，默认30天

        Returns:
            int: 清理的记录数
        """
        try:
            # 查找指定天数前的已验证会话记录
            cutoff_time = datetime.now(UTC) - timedelta(days=days_old)

            stmt = select(LoginSession).where(col(LoginSession.is_verified).is_(True))
            result = await db.exec(stmt)
            all_verified_sessions = result.all()

            # 筛选出过期的记录
            old_verified_sessions = [
                session
                for session in all_verified_sessions
                if session.verified_at and session.verified_at < cutoff_time
            ]

            # 删除旧的已验证记录
            deleted_count = 0
            for session in old_verified_sessions:
                await db.delete(session)
                deleted_count += 1

            await db.commit()

            if deleted_count > 0:
                logger.debug(
                    f"[Cleanup Service] Cleaned up {deleted_count} verified sessions older than {days_old} days"
                )

            return deleted_count

        except Exception as e:
            await db.rollback()
            logger.error(f"[Cleanup Service] Error cleaning old verified sessions: {e!s}")
            return 0

    @staticmethod
    async def run_full_cleanup(db: AsyncSession) -> dict[str, int]:
        """
        运行完整的清理流程

        Args:
            db: 数据库会话

        Returns:
            dict: 各项清理的结果统计
        """
        results = {}

        # 清理过期的验证码
        results["expired_verification_codes"] = await DatabaseCleanupService.cleanup_expired_verification_codes(db)

        # 清理过期的登录会话
        results["expired_login_sessions"] = await DatabaseCleanupService.cleanup_expired_login_sessions(db)

        # 清理7天前的已使用验证码
        results["old_used_verification_codes"] = await DatabaseCleanupService.cleanup_old_used_verification_codes(db, 7)

        # 清理30天前的已验证会话
        results["old_verified_sessions"] = await DatabaseCleanupService.cleanup_old_verified_sessions(db, 30)

        total_cleaned = sum(results.values())
        if total_cleaned > 0:
            logger.debug(
                f"[Cleanup Service] Full cleanup completed, total cleaned: {total_cleaned} records - {results}"
            )

        return results

    @staticmethod
    async def get_cleanup_statistics(db: AsyncSession) -> dict[str, int]:
        """
        获取清理统计信息

        Args:
            db: 数据库会话

        Returns:
            dict: 统计信息
        """
        try:
            current_time = datetime.now(UTC)
            cutoff_7_days = current_time - timedelta(days=7)
            cutoff_30_days = current_time - timedelta(days=30)

            # 统计过期的验证码数量
            expired_codes_stmt = select(EmailVerification).where(EmailVerification.expires_at < current_time)
            expired_codes_result = await db.exec(expired_codes_stmt)
            expired_codes_count = len(expired_codes_result.all())

            # 统计过期的登录会话数量
            expired_sessions_stmt = select(LoginSession).where(LoginSession.expires_at < current_time)
            expired_sessions_result = await db.exec(expired_sessions_stmt)
            expired_sessions_count = len(expired_sessions_result.all())

            # 统计7天前的已使用验证码数量
            old_used_codes_stmt = select(EmailVerification).where(col(EmailVerification.is_used).is_(True))
            old_used_codes_result = await db.exec(old_used_codes_stmt)
            all_used_codes = old_used_codes_result.all()
            old_used_codes_count = len(
                [code for code in all_used_codes if code.used_at and code.used_at < cutoff_7_days]
            )

            # 统计30天前的已验证会话数量
            old_verified_sessions_stmt = select(LoginSession).where(col(LoginSession.is_verified).is_(True))
            old_verified_sessions_result = await db.exec(old_verified_sessions_stmt)
            all_verified_sessions = old_verified_sessions_result.all()
            old_verified_sessions_count = len(
                [
                    session
                    for session in all_verified_sessions
                    if session.verified_at and session.verified_at < cutoff_30_days
                ]
            )

            return {
                "expired_verification_codes": expired_codes_count,
                "expired_login_sessions": expired_sessions_count,
                "old_used_verification_codes": old_used_codes_count,
                "old_verified_sessions": old_verified_sessions_count,
                "total_cleanable": expired_codes_count
                + expired_sessions_count
                + old_used_codes_count
                + old_verified_sessions_count,
            }

        except Exception as e:
            logger.error(f"[Cleanup Service] Error getting cleanup statistics: {e!s}")
            return {
                "expired_verification_codes": 0,
                "expired_login_sessions": 0,
                "old_used_verification_codes": 0,
                "old_verified_sessions": 0,
                "total_cleanable": 0,
            }