const express = require('express');
const router = express.Router();
const http = require('http');

/**
 * Data Retention Metrics Proxy
 * Proxies requests to the data retention microservice
 */

const DATA_RETENTION_HOST = process.env.DATA_RETENTION_HOST || 'data-retention';
const DATA_RETENTION_PORT = process.env.DATA_RETENTION_PORT || 3001;

/**
 * Make HTTP request to data retention service
 */
function makeRequest(path) {
  return new Promise((resolve, reject) => {
    const options = {
      hostname: DATA_RETENTION_HOST,
      port: DATA_RETENTION_PORT,
      path: path,
      method: 'GET',
      timeout: 5000
    };

    const req = http.request(options, (res) => {
      let data = '';
      
      res.on('data', (chunk) => {
        data += chunk;
      });
      
      res.on('end', () => {
        try {
          const result = JSON.parse(data);
          resolve({ status: res.statusCode, data: result });
        } catch (error) {
          reject(new Error(`Failed to parse response: ${error.message}`));
        }
      });
    });

    req.on('error', (error) => {
      reject(new Error(`Request failed: ${error.message}`));
    });

    req.on('timeout', () => {
      req.destroy();
      reject(new Error('Request timeout'));
    });

    req.end();
  });
}

/**
 * GET /api/data-retention/metrics
 * Get detailed metrics from data retention service
 */
router.get('/metrics', async (req, res) => {
  try {
    const response = await makeRequest('/metrics');
    
    if (response.status === 200) {
      res.json({
        success: true,
        data: response.data,
        timestamp: new Date().toISOString()
      });
    } else {
      res.status(response.status).json({
        success: false,
        error: 'Failed to fetch metrics from data retention service'
      });
    }
  } catch (error) {
    console.error('Data retention metrics error:', error);
    res.status(503).json({
      success: false,
      error: 'Data retention service unavailable',
      details: error.message
    });
  }
});

/**
 * GET /api/data-retention/health
 * Get health status from data retention service
 */
router.get('/health', async (req, res) => {
  try {
    const response = await makeRequest('/health');
    
    if (response.status === 200) {
      res.json({
        success: true,
        data: response.data,
        timestamp: new Date().toISOString()
      });
    } else {
      res.status(response.status).json({
        success: false,
        error: 'Failed to fetch health from data retention service'
      });
    }
  } catch (error) {
    console.error('Data retention health error:', error);
    res.status(503).json({
      success: false,
      error: 'Data retention service unavailable',
      details: error.message
    });
  }
});

/**
 * GET /api/data-retention/stats
 * Get basic statistics from data retention service
 */
router.get('/stats', async (req, res) => {
  try {
    const response = await makeRequest('/stats');
    
    if (response.status === 200) {
      res.json({
        success: true,
        data: response.data,
        timestamp: new Date().toISOString()
      });
    } else {
      res.status(response.status).json({
        success: false,
        error: 'Failed to fetch stats from data retention service'
      });
    }
  } catch (error) {
    console.error('Data retention stats error:', error);
    res.status(503).json({
      success: false,
      error: 'Data retention service unavailable',
      details: error.message
    });
  }
});

/**
 * GET /api/data-retention/status
 * Get combined status including service connectivity
 */
router.get('/status', async (req, res) => {
  try {
    const [healthResponse, metricsResponse] = await Promise.allSettled([
      makeRequest('/health'),
      makeRequest('/metrics')
    ]);

    const result = {
      success: true,
      service: {
        name: 'data-retention-service',
        connected: false,
        error: null
      },
      health: null,
      metrics: null,
      timestamp: new Date().toISOString()
    };

    if (healthResponse.status === 'fulfilled' && healthResponse.value.status === 200) {
      result.service.connected = true;
      result.health = healthResponse.value.data;
    } else {
      result.service.error = healthResponse.reason?.message || 'Health check failed';
    }

    if (metricsResponse.status === 'fulfilled' && metricsResponse.value.status === 200) {
      result.metrics = metricsResponse.value.data;
    }

    res.json(result);
    
  } catch (error) {
    console.error('Data retention status error:', error);
    res.status(503).json({
      success: false,
      error: 'Failed to get data retention service status',
      details: error.message
    });
  }
});

module.exports = router;