/**
 * LandveX Master Gateway
 * 
 * Unifies all backend services:
 * - Intelligence Lab (port 3002)
 * - Operations API (port 3005)
 * - Communications (port 3010)
 * - Apollo CRM (port 3001)
 * - AAMOS Ledger (port 3250)
 * - AAMOS Incidents (port 3303)
 */

import http from 'http';
import { GATEWAY_CONFIG, SERVICES } from './config';
import { requireAuth, requireRole, verifyApiKey } from './auth';
import { proxyRequest, checkServiceHealth } from './proxy';

// Service health status
const serviceHealth: Record<string, { healthy: boolean; latency: number; lastCheck: number; error?: string }> = {};

// Rate limiting (simple in-memory)
const rateLimits: Record<string, { count: number; resetAt: number }> = {};

function checkRateLimit(identifier: string, maxRequests: number): boolean {
  const now = Date.now();
  const windowStart = Math.floor(now / GATEWAY_CONFIG.rateLimitWindow) * GATEWAY_CONFIG.rateLimitWindow;
  
  if (!rateLimits[identifier] || rateLimits[identifier].resetAt < windowStart) {
    rateLimits[identifier] = { count: 0, resetAt: windowStart + GATEWAY_CONFIG.rateLimitWindow };
  }
  
  rateLimits[identifier].count++;
  return rateLimits[identifier].count <= maxRequests;
}

// CORS headers
function setCorsHeaders(res: http.ServerResponse): void {
  res.setHeader('Access-Control-Allow-Origin', '*');
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, PATCH, OPTIONS');
  res.setHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization, X-API-Key');
}

// Main server
const server = http.createServer(async (req, res) => {
  setCorsHeaders(res);

  if (req.method === 'OPTIONS') {
    res.statusCode = 204;
    res.end();
    return;
  }

  const url = req.url || '/';

  // Health check
  if (url === '/health') {
    res.setHeader('Content-Type', 'application/json');
    res.end(JSON.stringify({
      status: 'ok',
      version: '0.1.0-gateway',
      environment: GATEWAY_CONFIG.env,
      services: Object.entries(serviceHealth).map(([name, health]) => ({
        name,
        healthy: health.healthy,
        latency: health.latency,
        lastCheck: health.lastCheck,
        error: health.error,
      })),
    }));
    return;
  }

  // API Key auth for external API access
  const apiKey = req.headers['x-api-key'] as string;
  if (apiKey) {
    const keyInfo = verifyApiKey(apiKey);
    if (!keyInfo.valid) {
      res.statusCode = 401;
      res.end(JSON.stringify({ error: 'Invalid API key' }));
      return;
    }
    if (!checkRateLimit(apiKey, keyInfo.rateLimit || 100)) {
      res.statusCode = 429;
      res.end(JSON.stringify({ error: 'Rate limit exceeded' }));
      return;
    }
  }

  // Route to services
  if (url.startsWith('/api/v1/government') || url.startsWith('/api/v1/customers')) {
    proxyRequest(req, res, SERVICES.operations);
    return;
  } else if (url.startsWith('/api/v1/communications')) {
    proxyRequest(req, res, SERVICES.communications);
    return;
  } else if (url.startsWith('/api/v1/missions') || url.startsWith('/api/v1/artifacts')) {
    proxyRequest(req, res, SERVICES.intelligence);
    return;
  } else if (url.startsWith('/api/apollo')) {
    proxyRequest(req, res, SERVICES.apollo);
  } else if (url.startsWith('/api/ledger')) {
    proxyRequest(req, res, SERVICES.ledger);
  } else if (url.startsWith('/api/incidents')) {
    proxyRequest(req, res, SERVICES.incidents);
  } else if (url === '/webhooks/stripe') {
    // Stripe webhook — handle directly or proxy to billing
    res.statusCode = 200;
    res.end(JSON.stringify({ received: true }));
  } else {
    res.statusCode = 404;
    res.end(JSON.stringify({ error: 'Not Found', path: url }));
  }
});

// Health check loop
async function updateHealth() {
  for (const [name, service] of Object.entries(SERVICES)) {
    const health = await checkServiceHealth(service);
    serviceHealth[name] = {
      ...health,
      lastCheck: Date.now(),
    };
  }
}

// Initial health check
updateHealth();
setInterval(updateHealth, 30000); // Every 30 seconds

server.listen(GATEWAY_CONFIG.port, () => {
  console.log(`🚀 LandveX Gateway running on port ${GATEWAY_CONFIG.port}`);
  console.log(`📡 Services:`);
  Object.entries(SERVICES).forEach(([key, service]) => {
    console.log(`   - ${service.name}: http://${service.host}:${service.port}`);
  });
});