#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Redis 数据库操作模块
支持基本的键值操作
"""

import sys
import os
import json

# 避免文件名冲突，确保导入正确的redis库
try:
    from redis import Redis as RedisClient
    from redis import ConnectionError as RedisConnectionError
except ImportError as e:
    print(f"错误: 无法导入 redis 库，请确保已安装: pip install redis")
    print(f"详细错误: {e}")
    sys.exit(1)


class RedisDatabase:
    """Redis 数据库连接和操作类"""
    
    def __init__(self, host='localhost', port=6379, db=0, password=None):
        """
        初始化 Redis 连接参数
        :param host: Redis 主机地址
        :param port: Redis 端口
        :param db: 数据库编号（0-15）
        :param password: 密码（可选）
        """
        self.host = host
        self.port = port
        self.db = db
        self.password = password
        self.client = None
    
    def connect(self):
        """建立数据库连接"""
        try:
            self.client = RedisClient(
                host=self.host,
                port=self.port,
                db=self.db,
                password=self.password,
                decode_responses=True,
                socket_connect_timeout=5
            )
            # 测试连接
            self.client.ping()
            return True, "Redis 连接成功"
        except RedisConnectionError as e:
            return False, f"Redis 连接失败: 无法连接到 Redis 服务器 - {str(e)}"
        except Exception as e:
            return False, f"Redis 连接失败: {str(e)}"
    
    def execute(self, command):
        """
        执行 Redis 命令
        :param command: Redis 命令字符串
        示例: "SET key value" 或 "GET key"
        """
        if not self.client:
            return False, "未连接到数据库"
        
        try:
            # 解析命令
            parts = command.strip().split()
            if not parts:
                return False, "命令不能为空"
            
            cmd = parts[0].upper()
            args = parts[1:]
            
            # 执行常用命令
            if cmd == 'SET' and len(args) >= 2:
                key = args[0]
                value = ' '.join(args[1:])
                result = self.client.set(key, value)
                return True, "OK" if result else "FAIL"
            
            elif cmd == 'GET' and len(args) >= 1:
                key = args[0]
                result = self.client.get(key)
                return True, result if result is not None else "(nil)"
            
            elif cmd == 'DEL' and len(args) >= 1:
                result = self.client.delete(*args)
                return True, f"删除了 {result} 个键"
            
            elif cmd == 'EXISTS' and len(args) >= 1:
                result = self.client.exists(*args)
                return True, f"存在 {result} 个键"
            
            elif cmd == 'KEYS' and len(args) >= 1:
                pattern = args[0]
                result = self.client.keys(pattern)
                return True, result
            
            elif cmd == 'HSET' and len(args) >= 3:
                key = args[0]
                field = args[1]
                value = ' '.join(args[2:])
                result = self.client.hset(key, field, value)
                return True, f"设置字段成功: {result}"
            
            elif cmd == 'HGET' and len(args) >= 2:
                key = args[0]
                field = args[1]
                result = self.client.hget(key, field)
                return True, result if result is not None else "(nil)"
            
            elif cmd == 'HGETALL' and len(args) >= 1:
                key = args[0]
                result = self.client.hgetall(key)
                return True, result
            
            elif cmd == 'LPUSH' and len(args) >= 2:
                key = args[0]
                result = self.client.lpush(key, *args[1:])
                return True, f"列表长度: {result}"
            
            elif cmd == 'LRANGE' and len(args) >= 3:
                key = args[0]
                start = int(args[1])
                stop = int(args[2])
                result = self.client.lrange(key, start, stop)
                return True, result
            
            elif cmd == 'SADD' and len(args) >= 2:
                key = args[0]
                result = self.client.sadd(key, *args[1:])
                return True, f"添加了 {result} 个元素"
            
            elif cmd == 'SMEMBERS' and len(args) >= 1:
                key = args[0]
                result = self.client.smembers(key)
                return True, list(result)
            
            elif cmd == 'PING':
                result = self.client.ping()
                return True, "PONG" if result else "FAIL"
            
            elif cmd == 'FLUSHDB':
                result = self.client.flushdb()
                return True, "OK" if result else "FAIL"
            
            elif cmd == 'DBSIZE':
                result = self.client.dbsize()
                return True, f"数据库键数量: {result}"
            
            else:
                # 尝试执行原始命令
                result = self.client.execute_command(*parts)
                return True, result
                
        except Exception as e:
            return False, f"执行失败: {str(e)}"
    
    def close(self):
        """关闭数据库连接"""
        if self.client:
            self.client.close()
            self.client = None
            return "Redis 连接已关闭"
        return "连接已经关闭"