/**
 * SSH Stats API Endpoint
 * 
 * GET /api/stats/:host/:container - Get real-time docker stats for a container
 */

import { Router } from 'express';
import { Client } from 'ssh2';
import { readFileSync } from 'fs';
import { homedir } from 'os';
import { getHostConfigs } from '../config';
import { StatsResponse } from '../types';

const router = Router();

interface SSHConnectionConfig {
  host: string;
  port?: number;
  username: string;
  privateKey?: Buffer;
}

async function connectSSH(config: SSHConnectionConfig, timeout: number = 30000): Promise<Client> {
  return new Promise((resolve, reject) => {
    const conn = new Client();
    
    const timeoutId = setTimeout(() => {
      conn.end();
      reject(new Error('Connection timeout'));
    }, timeout);

    conn.on('ready', () => {
      clearTimeout(timeoutId);
      resolve(conn);
    });
    
    conn.on('error', (err) => {
      clearTimeout(timeoutId);
      reject(err);
    });
    
    conn.connect({
      host: config.host,
      port: config.port || 22,
      username: config.username,
      privateKey: config.privateKey,
      readyTimeout: timeout,
    });
  });
}

async function execSSH(conn: Client, command: string): Promise<string> {
  return new Promise((resolve, reject) => {
    conn.exec(command, (err, stream) => {
      if (err) {
        reject(err);
        return;
      }
      let output = '';
      stream.on('close', () => resolve(output));
      stream.on('data', (data: Buffer) => { output += data.toString(); });
      stream.stderr.on('data', (data: Buffer) => { output += data.toString(); });
    });
  });
}

async function getContainerStats(
  hostIp: string,
  containerName: string,
  sshUser: string,
  sshKeyPath?: string,
  sshPort?: number
): Promise<StatsResponse> {
  // Load SSH key
  const keyPath = sshKeyPath || `${homedir()}/.ssh/id_ed25519`;
  let privateKey: Buffer | undefined;
  try {
    privateKey = readFileSync(keyPath);
  } catch {
    // If key file doesn't exist, try without it
  }

  const sshConfig: SSHConnectionConfig = {
    host: hostIp,
    port: sshPort || 22,
    username: sshUser,
    privateKey,
  };

  const conn = await connectSSH(sshConfig, 30000);

  // Run docker stats with JSON format
  const dockerStatsCmd = `docker stats ${containerName} --no-stream --format '{"cpu":"{{.CPUPerc}}","mem":"{{.MemPerc}}","net":"{{.NetIO}}"}'`;
  const output = await execSSH(conn, dockerStatsCmd);

  conn.end();

  // Parse the output
  try {
    const parsed = JSON.parse(output.trim());
    
    // Parse CPU (remove % and convert to number)
    const cpu = parsed.cpu ? parseFloat(parsed.cpu.replace('%', '')) : 0;
    
    // Parse Memory (remove % and convert to number)
    const memory = parsed.mem ? parseFloat(parsed.mem.replace('%', '')) : 0;
    
    // Parse Network I/O (format: "1.2MB / 800kB" -> rx: "1.2MB", tx: "800kB")
    const netParts = parsed.net ? parsed.net.split(' / ') : ['0B', '0B'];
    const rx = netParts[0]?.trim() || '0B';
    const tx = netParts[1]?.trim() || '0B';

    return {
      cpu,
      memory,
      network: { rx, tx },
    };
  } catch (parseError) {
    return {
      cpu: 0,
      memory: 0,
      network: { rx: '0B', tx: '0B' },
      error: 'Failed to parse stats output',
    };
  }
}

// GET /api/stats/:host/:container
router.get('/stats/:host/:container', async (req, res) => {
  try {
    const { host, container } = req.params;
    
    // Find host config by name
    const hosts = await getHostConfigs();
    const hostConfig = hosts.find(h => h.name.toLowerCase() === host.toLowerCase());
    
    if (!hostConfig) {
      const response: StatsResponse = {
        cpu: 0,
        memory: 0,
        network: { rx: '0B', tx: '0B' },
        error: `Host '${host}' not found`,
      };
      return res.status(404).json(response);
    }

    const stats = await getContainerStats(
      hostConfig.ip,
      container,
      hostConfig.sshUser,
      hostConfig.sshKeyPath,
      hostConfig.sshPort
    );

    res.json(stats);
  } catch (error: any) {
    const response: StatsResponse = {
      cpu: 0,
      memory: 0,
      network: { rx: '0B', tx: '0B' },
      error: error.message || 'Failed to get stats',
    };
    res.status(500).json(response);
  }
});

export default router;