// Gateway Client - Communicates with spore-gateway for node discovery

const WebSocket = require('ws');

class GatewayClient {
  constructor(options = {}) {
    this.gatewayUrl = options.gatewayUrl || 'http://localhost:3001';
    this.filterAppLabel = options.filterAppLabel || 'pixelstream'; // Filter nodes by app label, set to null to disable
    this.nodes = new Map(); // ip -> { lastSeen, status, hostname, port }
    this.isRunning = false;
    this.ws = null;
    this.reconnectAttempts = 0;
    this.maxReconnectAttempts = 10;
    this.reconnectDelay = 2000;
    this.reconnectTimer = null;
  }

  start() {
    if (this.isRunning) {
      return;
    }

    this.isRunning = true;
    console.log(`Starting Gateway client, connecting to ${this.gatewayUrl}`);
    
    this.connectWebSocket();
  }

  stop() {
    if (!this.isRunning) {
      return;
    }

    this.isRunning = false;
    
    if (this.reconnectTimer) {
      clearTimeout(this.reconnectTimer);
      this.reconnectTimer = null;
    }
    
    if (this.ws) {
      this.ws.close();
      this.ws = null;
    }
    
    this.nodes.clear();
    console.log('Gateway client stopped');
  }

  connectWebSocket() {
    try {
      // Convert http:// to ws:// for WebSocket
      const wsUrl = this.gatewayUrl.replace('http://', 'ws://').replace('https://', 'wss://') + '/ws';
      console.log(`Connecting to WebSocket: ${wsUrl}`);
      
      this.ws = new WebSocket(wsUrl);
      
      this.ws.on('open', () => {
        console.log('WebSocket connected to gateway');
        this.reconnectAttempts = 0;
      });

      this.ws.on('message', (data) => {
        try {
          const message = JSON.parse(data.toString());
          this.handleWebSocketMessage(message);
        } catch (error) {
          console.error('Error parsing WebSocket message:', error);
        }
      });

      this.ws.on('close', (code, reason) => {
        console.log(`WebSocket connection closed: ${code} ${reason}`);
        if (this.isRunning) {
          this.scheduleReconnect();
        }
      });

      this.ws.on('error', (error) => {
        console.error('WebSocket error:', error.message);
      });

    } catch (error) {
      console.error('Failed to create WebSocket connection:', error);
      this.scheduleReconnect();
    }
  }

  handleWebSocketMessage(message) {
    if (message.topic === 'cluster/update') {
      this.handleClusterUpdate(message.members, message.primaryNode, message.totalNodes);
    } else if (message.topic === 'node/discovery') {
      this.handleNodeDiscovery(message.action, message.nodeIp);
    }
  }

  handleClusterUpdate(members, primaryNode, totalNodes) {
    const newNodes = new Map();
    
    if (members && Array.isArray(members)) {
      members.forEach(node => {
        // Filter for nodes with specified app label (if filtering is enabled)
        if (this.filterAppLabel && !this.hasAppLabel(node, this.filterAppLabel)) {
          return;
        }
        
        const nodeIp = node.ip || node.IP;
        newNodes.set(nodeIp, {
          lastSeen: Date.now(),
          status: node.status || node.Status || 'active',
          hostname: node.hostname || node.Hostname || nodeIp,
          port: node.port || node.Port || 4210,
          isPrimary: (primaryNode === nodeIp),
          labels: node.labels || node.Labels
        });
      });
    }
    
    // Check for newly discovered nodes
    for (const [ip, nodeInfo] of newNodes.entries()) {
      const existingNode = this.nodes.get(ip);
      if (!existingNode) {
        console.log(`Node discovered via gateway: ${ip} (${nodeInfo.hostname})`);
        this.nodes.set(ip, nodeInfo);
      } else if (existingNode.hostname !== nodeInfo.hostname) {
        console.log(`Node hostname updated: ${ip} -> ${nodeInfo.hostname}`);
        this.nodes.set(ip, nodeInfo);
      } else {
        // Update status and last seen
        existingNode.status = nodeInfo.status;
        existingNode.lastSeen = nodeInfo.lastSeen;
        existingNode.isPrimary = nodeInfo.isPrimary;
      }
    }
    
    // Check for lost nodes
    for (const ip of this.nodes.keys()) {
      if (!newNodes.has(ip)) {
        console.log(`Node lost via gateway: ${ip}`);
        this.nodes.delete(ip);
      }
    }
  }

  handleNodeDiscovery(action, nodeIp) {
    if (action === 'discovered') {
      // Node was discovered - actual data will come via cluster/update
      console.log(`Node discovered event: ${nodeIp}`);
    } else if (action === 'removed') {
      console.log(`Node removed event: ${nodeIp}`);
      this.nodes.delete(nodeIp);
    }
  }

  scheduleReconnect() {
    if (!this.isRunning) {
      return;
    }

    if (this.reconnectAttempts >= this.maxReconnectAttempts) {
      console.error('Max WebSocket reconnection attempts reached');
      return;
    }

    this.reconnectAttempts++;
    const delay = this.reconnectDelay * Math.pow(2, this.reconnectAttempts - 1);
    
    console.log(`Attempting to reconnect WebSocket in ${delay}ms (attempt ${this.reconnectAttempts})`);
    
    this.reconnectTimer = setTimeout(() => {
      this.connectWebSocket();
    }, delay);
  }

  getNodes() {
    return Array.from(this.nodes.entries()).map(([ip, node]) => ({
      ip,
      hostname: node.hostname || ip,
      port: node.port,
      status: node.status,
      isPrimary: node.isPrimary,
      ...node
    }));
  }

  getNodeCount() {
    return this.nodes.size;
  }

  hasAppLabel(node, appLabel) {
    // Check if node has the app: <appLabel> label
    if (!node.labels || typeof node.labels !== 'object') {
      return false;
    }
    
    return node.labels.app === appLabel;
  }
}

module.exports = GatewayClient;