/**
 * Integration Tests: Error Scenarios
 * 
 * Tests T025-T028: Error handling for /sitemap.xml endpoint
 * Tests: >50k documents (413), rate limiting (429), service unavailable (503), invalid endpoints (404)
 * 
 * @module tests/integration/error-scenarios
 */

import { describe, it, before, after } from 'node:test';
import assert from 'node:assert/strict';
import http from 'node:http';

const TEST_PORT = 3001;

// =============================================================================
// T025: Integration test for >50k documents (413 error)
// =============================================================================

describe('T025: /sitemap.xml with >50k Documents', () => {
  it('should return 413 when Drive contains more than 50,000 documents', async () => {
    // Mock Drive API to return count > 50,000
    // TODO: Configure mock to simulate large document count
    
    const response = await makeRequest(`http://localhost:${TEST_PORT}/sitemap.xml`);

    // Verify 413 Payload Too Large
    assert.equal(response.statusCode, 413, 'Should return 413 when documents exceed 50k limit');
    
    // Verify no response body (per spec: status code only, no body)
    assert.equal(response.body, '', 'Should have no response body for 413 error');
    
    // Verify no Content-Type header for error responses
    assert.equal(response.headers['content-type'], undefined, 'Should not have Content-Type header for errors');
  });
});

// =============================================================================
// T026: Integration test for Drive API rate limiting (429 error)
// =============================================================================

describe('T026: /sitemap.xml with Drive API Rate Limiting', () => {
  it('should return 429 with Retry-After header when Drive API rate limits', async () => {
    // Mock Drive API to return 429 with Retry-After header
    // TODO: Configure mock to simulate rate limit with Retry-After: 60
    
    const response = await makeRequest(`http://localhost:${TEST_PORT}/sitemap.xml`);

    // Verify 429 Too Many Requests
    assert.equal(response.statusCode, 429, 'Should return 429 when Drive API rate limits');
    
    // Verify Retry-After header is present (in seconds)
    assert.ok(response.headers['retry-after'], 'Should include Retry-After header');
    
    const retryAfter = parseInt(response.headers['retry-after']);
    assert.ok(retryAfter > 0, 'Retry-After should be a positive number (seconds)');
    
    // Verify no response body (per spec: status code only, no body)
    assert.equal(response.body, '', 'Should have no response body for 429 error');
  });

  it('should pass through Retry-After value from Drive API', async () => {
    // Mock Drive API to return specific Retry-After value
    const expectedRetryAfter = 120; // 2 minutes
    // TODO: Configure mock to return Retry-After: 120
    
    const response = await makeRequest(`http://localhost:${TEST_PORT}/sitemap.xml`);

    assert.equal(response.statusCode, 429, 'Should return 429');
    assert.equal(
      response.headers['retry-after'],
      String(expectedRetryAfter),
      'Should pass through exact Retry-After value from Drive API'
    );
  });
});

// =============================================================================
// T027: Integration test for Drive API 503 error (no retry)
// =============================================================================

describe('T027: /sitemap.xml with Drive API 503 Error', () => {
  it('should return 503 immediately without retry when Drive API is unavailable', async () => {
    // Mock Drive API to return 503 Service Unavailable
    // TODO: Configure mock to simulate Drive API 503 error
    
    const startTime = Date.now();
    const response = await makeRequest(`http://localhost:${TEST_PORT}/sitemap.xml`);
    const elapsed = Date.now() - startTime;

    // Verify 503 Service Unavailable (passthrough)
    assert.equal(response.statusCode, 503, 'Should return 503 when Drive API is unavailable');
    
    // Verify no response body (per spec: status code only, no body)
    assert.equal(response.body, '', 'Should have no response body for 503 error');
    
    // Verify NO retry was attempted (response should be immediate, < 1 second)
    assert.ok(elapsed < 1000, 'Should return immediately without retry (< 1 second)');
  });

  it('should NOT retry on Drive API 503 per specification', async () => {
    // Mock Drive API to track number of calls
    let driveApiCallCount = 0;
    // TODO: Configure mock to count API calls and return 503
    
    const response = await makeRequest(`http://localhost:${TEST_PORT}/sitemap.xml`);

    assert.equal(response.statusCode, 503, 'Should return 503');
    // Verify only ONE call was made (no retry)
    // assert.equal(driveApiCallCount, 1, 'Should call Drive API only once (no retry on 503)');
  });
});

// =============================================================================
// T028: Integration test for invalid endpoint requests (404 error)
// =============================================================================

describe('T028: Invalid Endpoint Requests', () => {
  it('should return 404 for non-/sitemap.xml paths', async () => {
    const invalidPaths = [
      '/',
      '/documents/abc123',
      '/api/documents',
      '/health',
      '/status',
      '/favicon.ico',
      '/documents/abc123/export'
    ];

    for (const path of invalidPaths) {
      const response = await makeRequest(`http://localhost:${TEST_PORT}${path}`);

      // Verify 404 Not Found
      assert.equal(
        response.statusCode,
        404,
        `Should return 404 for invalid path: ${path}`
      );
      
      // Verify no response body (per spec: status code only, no body)
      assert.equal(
        response.body,
        '',
        `Should have no response body for 404 error on path: ${path}`
      );
      
      // Verify no Content-Type header
      assert.equal(
        response.headers['content-type'],
        undefined,
        `Should not have Content-Type header for 404 on path: ${path}`
      );
    }
  });

  it('should return 404 for POST/PUT/DELETE requests to /sitemap.xml', async () => {
    // Only GET is allowed, all other methods should return 404
    const methods = ['POST', 'PUT', 'DELETE', 'PATCH'];

    for (const method of methods) {
      const response = await makeRequestWithMethod(
        `http://localhost:${TEST_PORT}/sitemap.xml`,
        method
      );

      // Note: Spec says 404 for non-/sitemap.xml paths, but should also handle wrong methods
      // Could be 404 or 405, depending on implementation - check spec
      assert.ok(
        response.statusCode === 404 || response.statusCode === 405,
        `Should return 404 or 405 for ${method} method`
      );
      
      assert.equal(response.body, '', 'Should have no response body for method errors');
    }
  });
});

// =============================================================================
// Helper Functions
// =============================================================================

/**
 * Make HTTP GET request
 * @param {string} url - Full URL to request
 * @returns {Promise<Object>} Response object
 */
function makeRequest(url) {
  return new Promise((resolve, reject) => {
    http.get(url, (res) => {
      let body = '';
      res.on('data', chunk => body += chunk);
      res.on('end', () => {
        resolve({
          statusCode: res.statusCode,
          headers: res.headers,
          body
        });
      });
    }).on('error', reject);
  });
}

/**
 * Make HTTP request with specific method
 * @param {string} url - Full URL to request
 * @param {string} method - HTTP method
 * @returns {Promise<Object>} Response object
 */
function makeRequestWithMethod(url, method) {
  return new Promise((resolve, reject) => {
    const urlObj = new URL(url);
    const options = {
      hostname: urlObj.hostname,
      port: urlObj.port,
      path: urlObj.pathname,
      method: method
    };

    const req = http.request(options, (res) => {
      let body = '';
      res.on('data', chunk => body += chunk);
      res.on('end', () => {
        resolve({
          statusCode: res.statusCode,
          headers: res.headers,
          body
        });
      });
    });

    req.on('error', reject);
    req.end();
  });
}