//! DIAP网络适配器
//!
//! 集成DIAP SDK的网络功能，提供P2P通信和身份验证网络层。

use std::collections::HashMap;
use std::sync::Arc;
use tokio::sync::RwLock;
// use futures::stream::StreamExt;

use super::config::{DiapConfig, P2pType};
use super::DiapError;

/// 网络节点信息
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub struct NetworkNode {
    /// 节点ID
    pub node_id: String,
    
    /// 节点地址
    pub addresses: Vec<String>,
    
    /// 节点身份ID
    pub identity_id: Option<String>,
    
    /// 连接状态
    pub connection_status: ConnectionStatus,
    
    /// 最后活跃时间
    pub last_active: i64,
    
    /// 节点元数据
    pub metadata: serde_json::Value,
}

/// 连接状态
#[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
pub enum ConnectionStatus {
    /// 断开连接
    Disconnected,
    
    /// 连接中
    Connecting,
    
    /// 已连接
    Connected,
    
    /// 错误状态
    Error,
}

/// 网络消息
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub struct NetworkMessage {
    /// 消息ID
    pub message_id: String,
    
    /// 发送者身份ID
    pub sender_id: String,
    
    /// 接收者身份ID（None表示广播）
    pub receiver_id: Option<String>,
    
    /// 消息类型
    pub message_type: MessageType,
    
    /// 消息内容
    pub payload: serde_json::Value,
    
    /// 时间戳
    pub timestamp: i64,
    
    /// 消息签名
    pub signature: Option<String>,
}

/// 消息类型
#[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
pub enum MessageType {
    /// 身份验证请求
    AuthRequest,
    
    /// 身份验证响应
    AuthResponse,
    
    /// 数据请求
    DataRequest,
    
    /// 数据响应
    DataResponse,
    
    /// 心跳消息
    Heartbeat,
    
    /// 共识消息
    ConsensusMessage,
    
    /// 信誉更新
    ReputationUpdate,
    
    /// 自定义消息
    Custom,
}

/// DIAP网络适配器
#[derive(Debug, Clone)]
pub struct DiapNetworkAdapter {
    /// 配置
    config: DiapConfig,
    
    /// 身份管理器引用
    identity_manager: Arc<super::identity_manager::DiapIdentityManager>,
    
    /// 网络节点缓存
    network_nodes: Arc<RwLock<HashMap<String, NetworkNode>>>,
    
    /// 消息队列
    message_queue: Arc<RwLock<Vec<NetworkMessage>>>,
    
    /// 是否正在运行
    is_running: Arc<RwLock<bool>>,
}

impl DiapNetworkAdapter {
    /// 创建新的网络适配器
    pub async fn new(
        config: DiapConfig,
        identity_manager: Arc<super::identity_manager::DiapIdentityManager>,
    ) -> Result<Self, DiapError> {
        log::info!("初始化DIAP网络适配器");
        
        let adapter = Self {
            config,
            identity_manager,
            network_nodes: Arc::new(RwLock::new(HashMap::new())),
            message_queue: Arc::new(RwLock::new(Vec::new())),
            is_running: Arc::new(RwLock::new(false)),
        };
        
        Ok(adapter)
    }
    
    /// 启动网络适配器
    pub async fn start(&self) -> Result<(), DiapError> {
        log::info!("启动DIAP网络适配器");
        
        // 检查配置
        if !self.config.network.enable_p2p {
            log::warn!("P2P网络未启用，网络适配器将以本地模式运行");
            return Ok(());
        }
        
        // 设置运行状态
        {
            let mut running = self.is_running.write().await;
            *running = true;
        }
        
        // 根据配置启动相应的网络
        match self.config.network.p2p_type {
            P2pType::Libp2p => self.start_libp2p_network().await,
            P2pType::Iroh => self.start_iroh_network().await,
            P2pType::Hybrid => self.start_hybrid_network().await,
        }
    }
    
    /// 停止网络适配器
    pub async fn stop(&self) -> Result<(), DiapError> {
        log::info!("停止DIAP网络适配器");
        
        // 设置运行状态
        {
            let mut running = self.is_running.write().await;
            *running = false;
        }
        
        // 清理网络节点
        {
            let mut nodes = self.network_nodes.write().await;
            nodes.clear();
        }
        
        // 清理消息队列
        {
            let mut queue = self.message_queue.write().await;
            queue.clear();
        }
        
        Ok(())
    }
    
    /// 启动libp2p网络
    async fn start_libp2p_network(&self) -> Result<(), DiapError> {
        log::info!("启动libp2p网络");
        
        // 这里应该集成DIAP SDK的libp2p功能
        // 由于DIAP SDK的具体API需要进一步研究，这里先实现一个简化版本
        
        // 添加引导节点到网络节点缓存
        for (index, bootstrap_node) in self.config.network.bootstrap_nodes.iter().enumerate() {
            let node = NetworkNode {
                node_id: format!("bootstrap-{}", index),
                addresses: vec![bootstrap_node.clone()],
                identity_id: None,
                connection_status: ConnectionStatus::Disconnected,
                last_active: chrono::Utc::now().timestamp(),
                metadata: serde_json::json!({
                    "type": "bootstrap",
                    "source": "config",
                }),
            };
            
            let mut nodes = self.network_nodes.write().await;
            nodes.insert(node.node_id.clone(), node);
        }
        
        log::info!("libp2p网络初始化完成，已添加 {} 个引导节点", self.config.network.bootstrap_nodes.len());
        
        Ok(())
    }
    
    /// 启动Iroh网络
    async fn start_iroh_network(&self) -> Result<(), DiapError> {
        log::info!("启动Iroh网络");
        
        // 这里应该集成DIAP SDK的Iroh功能
        // 由于DIAP SDK的具体API需要进一步研究，这里先实现一个简化版本
        
        log::info!("Iroh网络初始化完成");
        
        Ok(())
    }
    
    /// 启动混合网络
    async fn start_hybrid_network(&self) -> Result<(), DiapError> {
        log::info!("启动混合网络 (libp2p + Iroh)");
        
        // 启动libp2p网络
        self.start_libp2p_network().await?;
        
        // 启动Iroh网络
        self.start_iroh_network().await?;
        
        log::info!("混合网络初始化完成");
        
        Ok(())
    }
    
    /// 发送网络消息
    pub async fn send_message(&self, message: NetworkMessage) -> Result<(), DiapError> {
        log::debug!("发送网络消息: {} -> {:?}", message.sender_id, message.receiver_id);
        
        // 验证发送者身份
        let current_identity = self.identity_manager.get_current_identity().await;
        if current_identity.is_none() || current_identity.as_ref().unwrap().id != message.sender_id {
            return Err(DiapError::AuthenticationFailed("发送者身份验证失败".to_string()));
        }
        
        // 根据消息类型处理
        match message.message_type {
            MessageType::Heartbeat => {
                // 心跳消息，直接处理
                self.handle_heartbeat_message(&message).await?;
            }
            MessageType::AuthRequest | MessageType::AuthResponse => {
                // 身份验证消息，需要特殊处理，使用 Box::pin 避免递归
                Box::pin(self.handle_auth_message(&message)).await?;
            }
            _ => {
                // 其他消息，添加到队列等待处理
                let mut queue = self.message_queue.write().await;
                queue.push(message);
            }
        }
        
        Ok(())
    }
    
    /// 接收网络消息
    pub async fn receive_messages(&self, limit: usize) -> Vec<NetworkMessage> {
        let mut queue = self.message_queue.write().await;
        
        if queue.is_empty() {
            return Vec::new();
        }
        
        let messages: Vec<NetworkMessage> = if limit == 0 || limit >= queue.len() {
            queue.drain(..).collect()
        } else {
            queue.drain(..limit).collect()
        };
        
        messages
    }
    
    /// 获取网络节点列表
    pub async fn get_network_nodes(&self) -> Vec<NetworkNode> {
        let nodes = self.network_nodes.read().await;
        nodes.values().cloned().collect()
    }
    
    /// 连接到特定节点
    pub async fn connect_to_node(&self, node_id: &str) -> Result<(), DiapError> {
        log::info!("连接到节点: {}", node_id);
        
        let mut nodes = self.network_nodes.write().await;
        
        if let Some(node) = nodes.get_mut(node_id) {
            node.connection_status = ConnectionStatus::Connecting;
            node.last_active = chrono::Utc::now().timestamp();
            
            // 模拟连接过程
            tokio::time::sleep(tokio::time::Duration::from_millis(100)).await;
            
            node.connection_status = ConnectionStatus::Connected;
            
            log::info!("已连接到节点: {}", node_id);
            Ok(())
        } else {
            Err(DiapError::NetworkError(format!("节点不存在: {}", node_id)))
        }
    }
    
    /// 断开节点连接
    pub async fn disconnect_from_node(&self, node_id: &str) -> Result<(), DiapError> {
        log::info!("断开节点连接: {}", node_id);
        
        let mut nodes = self.network_nodes.write().await;
        
        if let Some(node) = nodes.get_mut(node_id) {
            node.connection_status = ConnectionStatus::Disconnected;
            log::info!("已断开节点连接: {}", node_id);
            Ok(())
        } else {
            Err(DiapError::NetworkError(format!("节点不存在: {}", node_id)))
        }
    }
    
    /// 发现新节点
    pub async fn discover_nodes(&self) -> Result<Vec<NetworkNode>, DiapError> {
        log::info!("发现网络节点");
        
        // 这里应该实现节点发现逻辑
        // 暂时返回空列表
        Ok(Vec::new())
    }
    
    /// 处理心跳消息
    async fn handle_heartbeat_message(&self, message: &NetworkMessage) -> Result<(), DiapError> {
        log::trace!("处理心跳消息: {}", message.message_id);
        
        // 更新发送者节点的最后活跃时间
        let mut nodes = self.network_nodes.write().await;
        
        // 查找发送者节点
        for node in nodes.values_mut() {
            if node.identity_id.as_ref() == Some(&message.sender_id) {
                node.last_active = chrono::Utc::now().timestamp();
                node.connection_status = ConnectionStatus::Connected;
                break;
            }
        }
        
        Ok(())
    }
    
    /// 处理身份验证消息
    async fn handle_auth_message(&self, message: &NetworkMessage) -> Result<(), DiapError> {
        log::debug!("处理身份验证消息: {}", message.message_id);
        
        match message.message_type {
            MessageType::AuthRequest => {
                // 收到身份验证请求
                self.handle_auth_request(message).await
            }
            MessageType::AuthResponse => {
                // 收到身份验证响应
                self.handle_auth_response(message).await
            }
            _ => {
                Err(DiapError::InternalError("非身份验证消息类型".to_string()))
            }
        }
    }
    
    /// 处理身份验证请求
    async fn handle_auth_request(&self, message: &NetworkMessage) -> Result<(), DiapError> {
        // 验证请求者身份
        let auth_result = self.identity_manager.verify_identity(&message.sender_id, None).await?;
        
        if !auth_result.authenticated {
            return Err(DiapError::AuthenticationFailed("请求者身份验证失败".to_string()));
        }
        
        // 创建验证响应
        let response = NetworkMessage {
            message_id: uuid::Uuid::new_v4().to_string(),
            sender_id: {
                let current_identity = self.identity_manager.get_current_identity().await;
                current_identity.map(|id| id.id).unwrap_or_default()
            },
            receiver_id: Some(message.sender_id.clone()),
            message_type: MessageType::AuthResponse,
            payload: serde_json::json!({
                "request_id": message.message_id,
                "authenticated": auth_result.authenticated,
                "timestamp": chrono::Utc::now().timestamp(),
            }),
            timestamp: chrono::Utc::now().timestamp(),
            signature: None,
        };
        
        // 发送响应，使用 Box::pin 避免递归
        Box::pin(self.send_message(response)).await?;
        
        Ok(())
    }
    
    /// 处理身份验证响应
    async fn handle_auth_response(&self, _message: &NetworkMessage) -> Result<(), DiapError> {
        // 这里应该处理身份验证响应
        // 暂时只记录日志
        log::debug!("收到身份验证响应");
        
        Ok(())
    }
    
    /// 检查网络状态
    pub async fn check_network_status(&self) -> NetworkStatus {
        let nodes = self.network_nodes.read().await;
        let running = self.is_running.read().await;
        
        let total_nodes = nodes.len();
        let connected_nodes = nodes.values().filter(|n| n.connection_status == ConnectionStatus::Connected).count();
        
        NetworkStatus {
            is_running: *running,
            total_nodes,
            connected_nodes,
            active_connections: connected_nodes,
            last_check: chrono::Utc::now().timestamp(),
        }
    }
}

/// 网络状态
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub struct NetworkStatus {
    /// 是否正在运行
    pub is_running: bool,
    
    /// 总节点数
    pub total_nodes: usize,
    
    /// 已连接节点数
    pub connected_nodes: usize,
    
    /// 活跃连接数
    pub active_connections: usize,
    
    /// 最后检查时间
    pub last_check: i64,
}

impl Default for DiapNetworkAdapter {
    fn default() -> Self {
        // 注意：这个默认实现主要用于测试
        let config = DiapConfig::default();
        let identity_manager = Arc::new(super::identity_manager::DiapIdentityManager::default());
        
        Self {
            config,
            identity_manager,
            network_nodes: Arc::new(RwLock::new(HashMap::new())),
            message_queue: Arc::new(RwLock::new(Vec::new())),
            is_running: Arc::new(RwLock::new(false)),
        }
    }
}
