stock-bot/apps/data-services/data-catalog/src/controllers/HealthController.ts

import { Hono } from 'hono';

export class HealthController {
  private app: Hono;

  constructor() {
    this.app = new Hono();
    this.setupRoutes();
  }

  private setupRoutes() {
    // Basic health check
    this.app.get('/', async (c) => {
      return c.json({
        service: 'data-catalog',
        status: 'healthy',
        timestamp: new Date().toISOString(),
        version: process.env.SERVICE_VERSION || '1.0.0'
      });
    });

    // Detailed health check
    this.app.get('/detailed', async (c) => {
      try {
        const healthStatus = {
          service: 'data-catalog',
          status: 'healthy',
          timestamp: new Date().toISOString(),
          version: process.env.SERVICE_VERSION || '1.0.0',
          uptime: process.uptime(),
          memory: process.memoryUsage(),
          dependencies: {
            database: await this.checkDatabase(),
            search: await this.checkSearchService(),
            eventBus: await this.checkEventBus()
          }
        };

        // Determine overall status based on dependencies
        const hasUnhealthyDependencies = Object.values(healthStatus.dependencies)
          .some(dep => dep.status !== 'healthy');

        if (hasUnhealthyDependencies) {
          healthStatus.status = 'degraded';
        }

        const statusCode = healthStatus.status === 'healthy' ? 200 : 503;
        return c.json(healthStatus, statusCode);
      } catch (error) {
        console.error('Health check error:', error);
        return c.json({
          service: 'data-catalog',
          status: 'unhealthy',
          timestamp: new Date().toISOString(),
          error: error instanceof Error ? error.message : 'Unknown error'
        }, 503);
      }
    });

    // Readiness check
    this.app.get('/ready', async (c) => {
      try {
        // Check if service is ready to accept requests
        const readyChecks = await Promise.all([
          this.checkDatabase(),
          this.checkSearchService()
        ]);

        const isReady = readyChecks.every(check => check.status === 'healthy');

        if (isReady) {
          return c.json({
            service: 'data-catalog',
            ready: true,
            timestamp: new Date().toISOString()
          });
        } else {
          return c.json({
            service: 'data-catalog',
            ready: false,
            timestamp: new Date().toISOString(),
            checks: readyChecks
          }, 503);
        }
      } catch (error) {
        console.error('Readiness check error:', error);
        return c.json({
          service: 'data-catalog',
          ready: false,
          timestamp: new Date().toISOString(),
          error: error instanceof Error ? error.message : 'Unknown error'
        }, 503);
      }
    });

    // Liveness check
    this.app.get('/live', async (c) => {
      return c.json({
        service: 'data-catalog',
        alive: true,
        timestamp: new Date().toISOString()
      });
    });
  }

  private async checkDatabase(): Promise<{ name: string; status: string; responseTime?: number }> {
    const start = Date.now();
    try {
      // Simulate database check
      // In real implementation, this would ping the actual database
      await new Promise(resolve => setTimeout(resolve, 10));
      
      return {
        name: 'database',
        status: 'healthy',
        responseTime: Date.now() - start
      };
    } catch (error) {
      return {
        name: 'database',
        status: 'unhealthy',
        responseTime: Date.now() - start
      };
    }
  }

  private async checkSearchService(): Promise<{ name: string; status: string; responseTime?: number }> {
    const start = Date.now();
    try {
      // Simulate search service check
      // In real implementation, this would check search index health
      await new Promise(resolve => setTimeout(resolve, 5));
      
      return {
        name: 'search',
        status: 'healthy',
        responseTime: Date.now() - start
      };
    } catch (error) {
      return {
        name: 'search',
        status: 'unhealthy',
        responseTime: Date.now() - start
      };
    }
  }

  private async checkEventBus(): Promise<{ name: string; status: string; responseTime?: number }> {
    const start = Date.now();
    try {
      // Simulate event bus check
      // In real implementation, this would check message broker connectivity
      await new Promise(resolve => setTimeout(resolve, 3));
      
      return {
        name: 'eventBus',
        status: 'healthy',
        responseTime: Date.now() - start
      };
    } catch (error) {
      return {
        name: 'eventBus',
        status: 'unhealthy',
        responseTime: Date.now() - start
      };
    }
  }

  public getApp(): Hono {
    return this.app;
  }
}