import sqlite3
from datetime import datetime
from PySide6.QtCore import QMutex 

"""
    sqlite消息数据库管理: db/messages.db
"""

class DBHelper:
    _instance = None  # 单例模式
    _mutex = QMutex() 

    def __new__(cls, db_name="db/messages.db"):
        """消息数据库连接管理器"""
        cls._mutex.lock()
        try:
            if not cls._instance:
                cls._instance = super().__new__(cls)
                cls._instance.db_name = db_name
                cls._instance._init_db()
        finally:
            cls._mutex.unlock()
        return cls._instance

    def _init_db(self):
        """创建消息表"""
        conn = sqlite3.connect(self.db_name)
        cursor = conn.cursor()
        # 创建消息表：id(主键)、内容、类型(1=系统消息，2=预警)、是否处理、创建时间
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS messages (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                content TEXT NOT NULL,
                message_type INTEGER NOT NULL,  -- 1: normal, 2: warning
                is_processed INTEGER NOT NULL DEFAULT 0, -- 为1表示已经解决/已经处理
                create_time TEXT NOT NULL,  -- 创建时间
                last_modified TEXT NOT NULL  -- 最后修改时间（新增/更新时都会变）
            )
        ''')
        conn.commit()
        conn.close()

    def insert_message(self, content, message_type, is_processed=0):
        """插入消息: create_time和last_modified一开始都设为当前时间"""
        current_time = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
        conn = sqlite3.connect(self.db_name)
        cursor = conn.cursor()
        cursor.execute('''
            INSERT INTO messages (content, message_type, is_processed, create_time, last_modified)
            VALUES (?, ?, ?, ?, ?)
        ''', (content, message_type, is_processed, current_time, current_time)) 
        conn.commit()
        conn.close()

    def update_processed_status(self, content, message_type, is_processed=1):
        """更新is_processed状态, 同时更新last_modified为当前时间"""
        current_time = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
        conn = sqlite3.connect(self.db_name)
        cursor = conn.cursor()
        cursor.execute('''
            UPDATE messages 
            SET is_processed = ?, last_modified = ? 
            WHERE content = ? AND message_type = ?
        ''', (is_processed, current_time, content, message_type))  # 更新last_modified
        conn.commit()
        conn.close()

    def get_latest_messages(self, message_type, limit=16):
        """查询最新limit条消息, 包含last_modified字段"""
        conn = sqlite3.connect(self.db_name)
        cursor = conn.cursor()
        # 按创建时间倒序（确保取最新的消息），返回时包含last_modified
        cursor.execute('''
            SELECT content, is_processed, create_time, last_modified 
            FROM messages 
            WHERE message_type = ? 
            ORDER BY create_time DESC 
            LIMIT ?
        ''', (message_type, limit))
        messages = cursor.fetchall()  # 结果：[(content, is_processed, create_time, last_modified), ...]
        conn.close()
        return messages[::-1]  # 反转后按时间正序排列


if __name__ == "__main__":
    """测试用例：向数据库插入测试消息"""
    import time

    # 创建DBHelper实例（会自动创建数据库和表）
    db = DBHelper()

    # # 插入系统状态消息（message_type=1）
    # db.insert_message(
    #     content="开始自动智能浇筑系统",
    #     message_type=1,  # 系统消息
    #     is_processed=False
    # )
    # time.sleep(1)
    # db.insert_message(
    #     content="智能浇筑系统启动成功",
    #     message_type=1,
    #     is_processed=False
    # )
    # time.sleep(1)
    # db.insert_message(
    #     content="上料斗载荷达到80%",
    #     message_type=1, # 系统消息
    #     is_processed=True  # 已处理
    # )

    # 插入预警消息（message_type=2）
    db.insert_message(
        content="振动频率异常",
        message_type=2,  # 预警消息
        is_processed=False  # 未处理
    )
    time.sleep(1)
    db.insert_message(
        content="料斗重量超出阈值",
        message_type=2, # 预警消息
        is_processed=True  # 已处理
    )