# Infinity数据库连接池实现

from typing import Dict, Any, List, Optional
import threading
import time
from contextlib import contextmanager
from conf.settings import vector_db_settings

class InfinityConnectionPool:
    """
    Infinity数据库连接池
    
    设计特点：
    1. 支持并发连接管理
    2. 连接自动回收和复用
    3. 连接超时和心跳检测
    4. 动态调整连接数量
    5. 线程安全
    """
    
    def __init__(
        self,
        host: str = vector_db_settings.infinity_host,
        port: str = vector_db_settings.infinity_sdk_port,
        database: str = vector_db_settings.infinity_database,
        min_connections: int = 2,
        max_connections: int = 10,
        connection_timeout: int = 30,
        idle_timeout: int = 300,
        heartbeat_interval: int = 60
    ):
        """
        初始化连接池
        
        Args:
            host: Infinity服务地址
            port: Infinity服务端口
            database: 数据库名称
            min_connections: 最小连接数
            max_connections: 最大连接数
            connection_timeout: 连接超时时间（秒）
            idle_timeout: 空闲连接超时时间（秒）
            heartbeat_interval: 心跳检测间隔（秒）
        """
        self.host = host
        self.port = port
        self.database = database
        self.min_connections = min_connections
        self.max_connections = max_connections
        self.connection_timeout = connection_timeout
        self.idle_timeout = idle_timeout
        self.heartbeat_interval = heartbeat_interval
        
        # 连接池状态
        self.connections = []  # 可用连接列表
        self.in_use = {}  # 正在使用的连接 {connection: thread_id}
        self.connection_count = 0  # 当前连接总数
        
        # 线程安全锁
        self.lock = threading.Lock()
        self.condition = threading.Condition(self.lock)
        
        # 初始化最小连接数
        self._init_connections()
        
        # 启动心跳检测线程
        self.heartbeat_thread = threading.Thread(target=self._heartbeat_check, daemon=True)
        self.heartbeat_thread.start()
    
    def _init_connections(self):
        """初始化最小连接数"""
        for _ in range(self.min_connections):
            self._create_connection()
    
    def _create_connection(self) -> Any:
        """创建新连接"""
        try:
            import infinity
            
            # 连接到Infinity服务
            connection = infinity.connect(
                infinity.NetworkAddress(self.host, self.port)
            )
                        
            # 注意：根据官方API，RemoteThriftInfinityConnection对象没有use_database方法
            # 数据库操作应该通过create_database、drop_database等方法直接指定数据库名称
            # 或者通过获取Database对象后再进行操作
            
            # 保存数据库名称，供后续操作使用
            connection.__dict__['_database'] = self.database
            
            # 记录连接创建时间
            connection.__dict__['_created_at'] = time.time()
            connection.__dict__['_last_used'] = time.time()
            connection.__dict__['_is_valid'] = True
            
            with self.lock:
                self.connections.append(connection)
                self.connection_count += 1
            
            return connection
        except Exception as e:
            raise Exception(f"Failed to create Infinity connection: {e}")
    
    def _is_valid_connection(self, connection: Any) -> bool:
        """检查连接是否有效"""
        try:
            # 通过执行简单查询检查连接是否有效
            connection.get_database(self.database)
            return True
        except Exception:
            return False
    
    def _heartbeat_check(self):
        """心跳检测，定期检查连接有效性并清理过期连接"""
        while True:
            time.sleep(self.heartbeat_interval)
            self._cleanup_connections()
    
    def _cleanup_connections(self):
        """清理无效或过期连接"""
        with self.lock:
            current_time = time.time()
            valid_connections = []
            
            for connection in self.connections:
                # 检查连接是否过期
                if current_time - connection.__dict__['_last_used'] > self.idle_timeout:
                    # 关闭过期连接
                    try:
                        connection.disconnect()
                        self.connection_count -= 1
                    except Exception:
                        pass
                elif not self._is_valid_connection(connection):
                    # 关闭无效连接
                    try:
                        connection.disconnect()
                        self.connection_count -= 1
                    except Exception:
                        pass
                else:
                    valid_connections.append(connection)
            
            self.connections = valid_connections
            
            # 确保连接数不低于最小值
            while self.connection_count < self.min_connections:
                self._create_connection()
    
    @contextmanager
    def get_connection(self, timeout: Optional[int] = None) -> Any:
        """
        获取一个连接，使用上下文管理器
        
        Args:
            timeout: 获取连接的超时时间（秒）
            
        Yields:
            Infinity连接对象
        """
        connection = None
        try:
            connection = self.acquire(timeout)
            yield connection
        finally:
            if connection:
                self.release(connection)
    
    def acquire(self, timeout: Optional[int] = None) -> Any:
        """
        获取一个连接
        
        Args:
            timeout: 获取连接的超时时间（秒）
            
        Returns:
            Infinity连接对象
            
        Raises:
            TimeoutError: 获取连接超时
        """
        end_time = time.time() + (timeout or self.connection_timeout)
        
        with self.lock:
            while True:
                # 检查是否有可用连接
                if self.connections:
                    # 获取一个连接
                    connection = self.connections.pop()
                    
                    # 检查连接是否有效
                    if self._is_valid_connection(connection):
                        connection.__dict__['_last_used'] = time.time()
                        self.in_use[connection] = threading.get_ident()
                        return connection
                    else:
                        # 连接无效，关闭并计数减一
                        try:
                            connection.disconnect()
                            self.connection_count -= 1
                        except Exception:
                            pass
                
                # 检查是否可以创建新连接
                elif self.connection_count < self.max_connections:
                    # 创建新连接
                    connection = self._create_connection()
                    connection.__dict__['_last_used'] = time.time()
                    self.in_use[connection] = threading.get_ident()
                    return connection
                
                # 等待连接释放
                remaining = end_time - time.time()
                if remaining <= 0:
                    raise TimeoutError("Timeout waiting for Infinity connection")
                
                # 等待连接释放或超时
                self.condition.wait(remaining)
    
    def release(self, connection: Any):
        """
        释放连接
        
        Args:
            connection: 要释放的连接
        """
        with self.lock:
            if connection in self.in_use:
                del self.in_use[connection]
                
                # 检查连接是否有效
                if self._is_valid_connection(connection):
                    connection.__dict__['_last_used'] = time.time()
                    self.connections.append(connection)
                    # 通知等待的线程
                    self.condition.notify()
                else:
                    # 连接无效，关闭并计数减一
                    try:
                        connection.disconnect()
                        self.connection_count -= 1
                    except Exception:
                        pass
    
    def close(self):
        """关闭所有连接"""
        with self.lock:
            # 关闭可用连接
            for connection in self.connections:
                try:
                    connection.disconnect()
                except Exception:
                    pass
            
            # 关闭正在使用的连接
            for connection in list(self.in_use.keys()):
                try:
                    connection.disconnect()
                except Exception:
                    pass
            
            self.connections = []
            self.in_use = {}
            self.connection_count = 0
    
    def get_status(self) -> Dict[str, Any]:
        """
        获取连接池状态
        
        Returns:
            连接池状态信息
        """
        with self.lock:
            return {
                "total_connections": self.connection_count,
                "available_connections": len(self.connections),
                "in_use_connections": len(self.in_use),
                "min_connections": self.min_connections,
                "max_connections": self.max_connections
            }