"""SQLite数据库操作模块 - 使用标准库sqlite3"""
import sqlite3
import json
import time
import logging
from typing import Optional, Dict, Any, List
from pathlib import Path
from config import DATABASE_PATH

logger = logging.getLogger(__name__)


class Database:
    """数据库管理类"""
    
    def __init__(self, db_path: str = DATABASE_PATH):
        """初始化数据库连接
        
        Args:
            db_path: 数据库文件路径
        """
        self.db_path = db_path
        self._conn: Optional[sqlite3.Connection] = None
        self._ensure_db_exists()
        self.init_tables()
    
    def _ensure_db_exists(self):
        """确保数据库目录存在"""
        db_dir = Path(self.db_path).parent
        db_dir.mkdir(parents=True, exist_ok=True)
    
    @property
    def conn(self) -> sqlite3.Connection:
        """获取数据库连接（懒加载）"""
        if self._conn is None:
            self._conn = sqlite3.connect(
                self.db_path,
                check_same_thread=False,  # 允许多线程访问
                isolation_level=None  # 自动提交
            )
            self._conn.row_factory = sqlite3.Row  # 支持字典式访问
        return self._conn
    
    def init_tables(self):
        """初始化数据库表"""
        cursor = self.conn.cursor()
        
        # 用户表
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS users (
                user_id INTEGER PRIMARY KEY,
                username TEXT,
                created_at INTEGER NOT NULL,
                last_active INTEGER NOT NULL
            )
        """)
        
        # 游戏状态表
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS game_states (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                chat_id INTEGER NOT NULL,
                user_id INTEGER NOT NULL,
                game_type TEXT NOT NULL,
                state_data TEXT,
                created_at INTEGER NOT NULL,
                updated_at INTEGER NOT NULL,
                UNIQUE(chat_id, user_id, game_type)
            )
        """)
        
        # 创建索引
        cursor.execute("""
            CREATE INDEX IF NOT EXISTS idx_chat_user 
            ON game_states(chat_id, user_id)
        """)
        
        # 游戏统计表
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS game_stats (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                user_id INTEGER NOT NULL,
                game_type TEXT NOT NULL,
                wins INTEGER DEFAULT 0,
                losses INTEGER DEFAULT 0,
                draws INTEGER DEFAULT 0,
                total_plays INTEGER DEFAULT 0,
                UNIQUE(user_id, game_type)
            )
        """)
        
        logger.info("数据库表初始化完成")
    
    # ===== 用户相关操作 =====
    
    def get_or_create_user(self, user_id: int, username: str = None) -> Dict:
        """获取或创建用户
        
        Args:
            user_id: 用户ID
            username: 用户名
            
        Returns:
            用户信息字典
        """
        cursor = self.conn.cursor()
        current_time = int(time.time())
        
        # 尝试获取用户
        cursor.execute(
            "SELECT * FROM users WHERE user_id = ?",
            (user_id,)
        )
        user = cursor.fetchone()
        
        if user:
            # 更新最后活跃时间
            cursor.execute(
                "UPDATE users SET last_active = ? WHERE user_id = ?",
                (current_time, user_id)
            )
            return dict(user)
        else:
            # 创建新用户
            cursor.execute(
                "INSERT INTO users (user_id, username, created_at, last_active) VALUES (?, ?, ?, ?)",
                (user_id, username, current_time, current_time)
            )
            return {
                'user_id': user_id,
                'username': username,
                'created_at': current_time,
                'last_active': current_time
            }
    
    # ===== 游戏状态相关操作 =====
    
    def get_game_state(self, chat_id: int, user_id: int, game_type: str) -> Optional[Dict]:
        """获取游戏状态
        
        Args:
            chat_id: 会话ID
            user_id: 用户ID
            game_type: 游戏类型
            
        Returns:
            游戏状态字典，如果不存在返回None
        """
        cursor = self.conn.cursor()
        cursor.execute(
            "SELECT * FROM game_states WHERE chat_id = ? AND user_id = ? AND game_type = ?",
            (chat_id, user_id, game_type)
        )
        row = cursor.fetchone()
        
        if row:
            state = dict(row)
            # 解析JSON数据
            if state.get('state_data'):
                state['state_data'] = json.loads(state['state_data'])
            return state
        return None
    
    def save_game_state(self, chat_id: int, user_id: int, game_type: str, state_data: Dict):
        """保存游戏状态
        
        Args:
            chat_id: 会话ID
            user_id: 用户ID
            game_type: 游戏类型
            state_data: 状态数据字典
        """
        cursor = self.conn.cursor()
        current_time = int(time.time())
        state_json = json.dumps(state_data, ensure_ascii=False)
        
        cursor.execute("""
            INSERT INTO game_states (chat_id, user_id, game_type, state_data, created_at, updated_at)
            VALUES (?, ?, ?, ?, ?, ?)
            ON CONFLICT(chat_id, user_id, game_type) 
            DO UPDATE SET state_data = ?, updated_at = ?
        """, (chat_id, user_id, game_type, state_json, current_time, current_time, 
              state_json, current_time))
        
        logger.debug(f"保存游戏状态: chat_id={chat_id}, user_id={user_id}, game_type={game_type}")
    
    def delete_game_state(self, chat_id: int, user_id: int, game_type: str):
        """删除游戏状态
        
        Args:
            chat_id: 会话ID
            user_id: 用户ID
            game_type: 游戏类型
        """
        cursor = self.conn.cursor()
        cursor.execute(
            "DELETE FROM game_states WHERE chat_id = ? AND user_id = ? AND game_type = ?",
            (chat_id, user_id, game_type)
        )
        logger.debug(f"删除游戏状态: chat_id={chat_id}, user_id={user_id}, game_type={game_type}")
    
    def cleanup_old_sessions(self, timeout: int = 1800):
        """清理过期的游戏会话
        
        Args:
            timeout: 超时时间（秒）
        """
        cursor = self.conn.cursor()
        cutoff_time = int(time.time()) - timeout
        
        cursor.execute(
            "DELETE FROM game_states WHERE updated_at < ?",
            (cutoff_time,)
        )
        deleted = cursor.rowcount
        
        if deleted > 0:
            logger.info(f"清理了 {deleted} 个过期游戏会话")
    
    # ===== 游戏统计相关操作 =====
    
    def get_game_stats(self, user_id: int, game_type: str) -> Dict:
        """获取游戏统计
        
        Args:
            user_id: 用户ID
            game_type: 游戏类型
            
        Returns:
            统计数据字典
        """
        cursor = self.conn.cursor()
        cursor.execute(
            "SELECT * FROM game_stats WHERE user_id = ? AND game_type = ?",
            (user_id, game_type)
        )
        row = cursor.fetchone()
        
        if row:
            return dict(row)
        else:
            # 返回默认值
            return {
                'user_id': user_id,
                'game_type': game_type,
                'wins': 0,
                'losses': 0,
                'draws': 0,
                'total_plays': 0
            }
    
    def update_game_stats(self, user_id: int, game_type: str, 
                         win: bool = False, loss: bool = False, draw: bool = False):
        """更新游戏统计
        
        Args:
            user_id: 用户ID
            game_type: 游戏类型
            win: 是否获胜
            loss: 是否失败
            draw: 是否平局
        """
        cursor = self.conn.cursor()
        
        # 使用UPSERT语法
        cursor.execute("""
            INSERT INTO game_stats (user_id, game_type, wins, losses, draws, total_plays)
            VALUES (?, ?, ?, ?, ?, 1)
            ON CONFLICT(user_id, game_type)
            DO UPDATE SET 
                wins = wins + ?,
                losses = losses + ?,
                draws = draws + ?,
                total_plays = total_plays + 1
        """, (user_id, game_type, int(win), int(loss), int(draw),
              int(win), int(loss), int(draw)))
        
        logger.debug(f"更新游戏统计: user_id={user_id}, game_type={game_type}")
    
    def close(self):
        """关闭数据库连接"""
        if self._conn:
            self._conn.close()
            self._conn = None
            logger.info("数据库连接已关闭")


# 全局数据库实例
_db_instance: Optional[Database] = None


def get_db() -> Database:
    """获取全局数据库实例（单例模式）"""
    global _db_instance
    if _db_instance is None:
        _db_instance = Database()
    return _db_instance