/**
 * Unit Tests: Request Routing Logic
 * 
 * Tests request routing and error mapping in proxy.js
 * Tests T015, T016, T050
 */

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

describe('Unit: handleRequest() Routing (T015)', () => {
  
  // Mock routing function (will be in proxy.js)
  function parseRoute(method, url) {
    if (method !== 'GET') {
      return { route: null, error: 'Method not allowed', statusCode: 405 };
    }
    
    const urlObj = new URL(url, 'http://localhost');
    const path = urlObj.pathname;
    
    if (path === '/health') {
      return { route: 'health' };
    }
    
    if (path === '/sitemap.xml') {
      return { route: 'sitemap' };
    }
    
    // Document route: /:documentId
    const docMatch = path.match(/^\/([a-zA-Z0-9_-]+)$/);
    if (docMatch) {
      return { route: 'document', documentId: docMatch[1] };
    }
    
    return { route: null, error: 'Not found', statusCode: 404 };
  }

  it('T015: should route /health to health check handler', () => {
    // Given: GET request to /health
    const method = 'GET';
    const url = '/health';
    
    // When: Parsing route
    const result = parseRoute(method, url);
    
    // Then: Should route to health
    assert.equal(result.route, 'health', 'Should route to health handler');
  });

  it('T015: should route /:documentId to document export handler', () => {
    // Given: GET request to /:documentId
    const method = 'GET';
    const url = '/1BxAA_testDocument123';
    
    // When: Parsing route
    const result = parseRoute(method, url);
    
    // Then: Should route to document handler
    assert.equal(result.route, 'document', 'Should route to document handler');
    assert.equal(result.documentId, '1BxAA_testDocument123', 'Should extract document ID');
  });

  it('T015: should route /sitemap.xml to sitemap handler', () => {
    // Given: GET request to /sitemap.xml
    const method = 'GET';
    const url = '/sitemap.xml';
    
    // When: Parsing route
    const result = parseRoute(method, url);
    
    // Then: Should route to sitemap
    assert.equal(result.route, 'sitemap', 'Should route to sitemap handler');
  });

  it('T015: should return 404 for unknown routes', () => {
    // Given: GET request to unknown path
    const method = 'GET';
    const url = '/unknown/path';
    
    // When: Parsing route
    const result = parseRoute(method, url);
    
    // Then: Should return 404
    assert.equal(result.route, null, 'Should not match any route');
    assert.equal(result.statusCode, 404, 'Should return 404 status');
  });

  it('T015: should return 405 for non-GET methods', () => {
    // Given: POST request
    const method = 'POST';
    const url = '/1BxAA_test';
    
    // When: Parsing route
    const result = parseRoute(method, url);
    
    // Then: Should return 405 Method Not Allowed
    assert.equal(result.route, null, 'Should not match any route');
    assert.equal(result.statusCode, 405, 'Should return 405 status');
  });

  it('T015: should extract documentId with hyphens and underscores', () => {
    // Given: Document ID with special allowed characters
    const urls = [
      '/1BxAA-test-123',
      '/1BxAA_test_123',
      '/1BxAA-test_123'
    ];
    
    // When: Parsing each route
    // Then: Should extract document IDs correctly
    urls.forEach(url => {
      const result = parseRoute('GET', url);
      assert.equal(result.route, 'document', `Should route ${url} to document handler`);
      assert.ok(result.documentId, `Should extract document ID from ${url}`);
    });
  });
});

describe('Unit: mapDriveError() (T016)', () => {
  
  // Mock error mapping function (will be in proxy.js)
  function mapDriveError(error) {
    // Handle GaxiosError from googleapis
    const statusCode = error.code || error.response?.status || 500;
    
    const mapping = {
      404: { status: 404, message: 'Not Found' },
      403: { status: 403, message: 'Forbidden' },
      401: { status: 401, message: 'Unauthorized' },
      429: { status: 429, message: 'Too Many Requests', retryAfter: 60 },
      500: { status: 500, message: 'Internal Server Error' },
      503: { status: 503, message: 'Service Unavailable' }
    };
    
    return mapping[statusCode] || { status: 500, message: 'Internal Server Error' };
  }

  it('T016: should convert Drive API 404 to HTTP 404', () => {
    // Given: Drive API 404 error
    const driveError = { code: 404, message: 'File not found' };
    
    // When: Mapping error
    const result = mapDriveError(driveError);
    
    // Then: Should map to HTTP 404
    assert.equal(result.status, 404, 'Should map to 404 status');
  });

  it('T016: should convert Drive API 403 to HTTP 403', () => {
    // Given: Drive API 403 error
    const driveError = { code: 403, message: 'Permission denied' };
    
    // When: Mapping error
    const result = mapDriveError(driveError);
    
    // Then: Should map to HTTP 403
    assert.equal(result.status, 403, 'Should map to 403 status');
  });

  it('T016: should convert Drive API 401 to HTTP 401', () => {
    // Given: Drive API 401 error
    const driveError = { code: 401, message: 'Invalid credentials' };
    
    // When: Mapping error
    const result = mapDriveError(driveError);
    
    // Then: Should map to HTTP 401
    assert.equal(result.status, 401, 'Should map to 401 status');
  });

  it('T016: should convert Drive API 429 to HTTP 429 with Retry-After', () => {
    // Given: Drive API rate limit error
    const driveError = { code: 429, message: 'Rate limit exceeded' };
    
    // When: Mapping error
    const result = mapDriveError(driveError);
    
    // Then: Should map to HTTP 429 with Retry-After
    assert.equal(result.status, 429, 'Should map to 429 status');
    assert.equal(result.retryAfter, 60, 'Should include Retry-After of 60 seconds');
  });

  it('T016: should convert Drive API 500 to HTTP 500', () => {
    // Given: Drive API internal error
    const driveError = { code: 500, message: 'Internal error' };
    
    // When: Mapping error
    const result = mapDriveError(driveError);
    
    // Then: Should map to HTTP 500
    assert.equal(result.status, 500, 'Should map to 500 status');
  });

  it('T016: should convert Drive API 503 to HTTP 503', () => {
    // Given: Drive API service unavailable
    const driveError = { code: 503, message: 'Service unavailable' };
    
    // When: Mapping error
    const result = mapDriveError(driveError);
    
    // Then: Should map to HTTP 503
    assert.equal(result.status, 503, 'Should map to 503 status');
  });

  it('should handle errors without code by checking response.status', () => {
    // Given: Error with response.status instead of code
    const driveError = {
      response: { status: 404, statusText: 'Not Found' },
      message: 'Request failed'
    };
    
    // When: Mapping error
    const result = mapDriveError(driveError);
    
    // Then: Should map using response.status
    assert.equal(result.status, 404, 'Should map using response.status');
  });

  it('should default to 500 for unknown error codes', () => {
    // Given: Error with unknown status code
    const driveError = { code: 999, message: 'Unknown error' };
    
    // When: Mapping error
    const result = mapDriveError(driveError);
    
    // Then: Should default to 500
    assert.equal(result.status, 500, 'Should default to 500 for unknown codes');
  });
});

describe('Unit: Rate Limiting (T050)', () => {
  
  // Mock rate limiter (will be in proxy.js)
  class RateLimiter {
    constructor(maxRequests = 100, windowMs = 60000) {
      this.maxRequests = maxRequests;
      this.windowMs = windowMs;
      this.requests = new Map(); // ip -> [timestamps]
    }
    
    checkLimit(ip) {
      const now = Date.now();
      const windowStart = now - this.windowMs;
      
      // Get existing requests for this IP
      let timestamps = this.requests.get(ip) || [];
      
      // Remove old timestamps outside window
      timestamps = timestamps.filter(ts => ts > windowStart);
      
      // Check if limit exceeded
      if (timestamps.length >= this.maxRequests) {
        const oldestRequest = timestamps[0];
        const retryAfter = Math.ceil((oldestRequest + this.windowMs - now) / 1000);
        
        return {
          allowed: false,
          statusCode: 429,
          retryAfter
        };
      }
      
      // Add current request
      timestamps.push(now);
      this.requests.set(ip, timestamps);
      
      return { allowed: true };
    }
    
    cleanup() {
      const now = Date.now();
      const windowStart = now - this.windowMs;
      
      for (const [ip, timestamps] of this.requests.entries()) {
        const filtered = timestamps.filter(ts => ts > windowStart);
        if (filtered.length === 0) {
          this.requests.delete(ip);
        } else {
          this.requests.set(ip, filtered);
        }
      }
    }
  }

  it('T050: should allow 100 requests from same IP within window', () => {
    // Given: Rate limiter with 100 req/min limit
    const limiter = new RateLimiter(100, 60000);
    const testIp = '192.168.1.1';
    
    // When: Making 100 requests
    let allowedCount = 0;
    for (let i = 0; i < 100; i++) {
      const result = limiter.checkLimit(testIp);
      if (result.allowed) allowedCount++;
    }
    
    // Then: All 100 requests should be allowed
    assert.equal(allowedCount, 100, 'Should allow 100 requests');
  });

  it('T050: should return 429 with Retry-After header on 101st request', () => {
    // Given: Rate limiter with 100 req/min limit
    const limiter = new RateLimiter(100, 60000);
    const testIp = '192.168.1.1';
    
    // When: Making 101 requests
    for (let i = 0; i < 100; i++) {
      limiter.checkLimit(testIp);
    }
    
    const result = limiter.checkLimit(testIp);
    
    // Then: 101st request should be rate limited
    assert.equal(result.allowed, false, 'Should not allow 101st request');
    assert.equal(result.statusCode, 429, 'Should return 429 status');
    assert.ok(result.retryAfter > 0, 'Should include Retry-After in seconds');
    assert.ok(result.retryAfter <= 60, 'Retry-After should be <= 60 seconds');
  });

  it('T050: should track requests per IP independently', () => {
    // Given: Rate limiter and multiple IPs
    const limiter = new RateLimiter(100, 60000);
    const ip1 = '192.168.1.1';
    const ip2 = '192.168.1.2';
    
    // When: Making 100 requests from each IP
    for (let i = 0; i < 100; i++) {
      limiter.checkLimit(ip1);
      limiter.checkLimit(ip2);
    }
    
    // Then: Both IPs should still be allowed (independent limits)
    const result1 = limiter.checkLimit(ip1);
    const result2 = limiter.checkLimit(ip2);
    
    assert.equal(result1.allowed, false, 'IP1 should be rate limited');
    assert.equal(result2.allowed, false, 'IP2 should be rate limited');
  });

  it('T050: should cleanup old entries outside time window', () => {
    // Given: Rate limiter with short window
    const limiter = new RateLimiter(10, 1000); // 10 req/sec for testing
    const testIp = '192.168.1.1';
    
    // When: Making requests then cleaning up
    for (let i = 0; i < 10; i++) {
      limiter.checkLimit(testIp);
    }
    
    // Wait for window to pass (simulate with manual cleanup)
    limiter.cleanup();
    
    // Then: Should have entries in map
    assert.ok(limiter.requests.has(testIp), 'Should have IP in requests map');
  });

  it('T050: should reset limit after time window expires', () => {
    // Given: Rate limiter with very short window
    const limiter = new RateLimiter(5, 100); // 5 req / 100ms
    const testIp = '192.168.1.1';
    
    // When: Filling up limit
    for (let i = 0; i < 5; i++) {
      limiter.checkLimit(testIp);
    }
    
    // Simulate time passing by manipulating timestamps
    const oldTimestamps = limiter.requests.get(testIp);
    const expiredTimestamps = oldTimestamps.map(ts => ts - 200); // Make them 200ms old
    limiter.requests.set(testIp, expiredTimestamps);
    
    // Then: New request should be allowed after window
    const result = limiter.checkLimit(testIp);
    assert.equal(result.allowed, true, 'Should allow request after window expires');
  });
});