/**
 * Deterministic SearXNG fixture for local testing.
 * Implements the API contract used by the RSS RAG plugin's SearXNG integration.
 * 
 * NO external services required. Runs entirely in-process.
 * 
 * Coverage:
 * - Empty results, malformed responses, timeouts
 * - Rate limits, unavailable services
 * - Scope restrictions, fallback behavior
 * - Format support for RSS/JSON responses
 */

const http = require('http');
const url = require('url');

let fixturePort = 3002;
let running = false;
let server;

// Synthetic SearXNG responses
const searxngResponses = {
  // Successful search results
  success: (query, count = 3) => ({
    results: Array.from({ length: count }, (_, i) => ({
      title: `${query} result ${i + 1}`,
      url: `https://example.com/article-${i + 1}`,
      content: `Content about ${query} number ${i + 1}`,
      published: new Date(Date.now() - i * 86400000).toISOString(),
    })),
    query,
    totalResults: count,
  }),
  
  // Empty results
  empty: (query) => ({
    results: [],
    query,
    totalResults: 0,
  }),
  
  // Malformed response
  malformed: () => ({
    error: 'Malformed response from SearXNG',
  }),
  
  // Rate limited
  rateLimited: (query) => ({
    error: 'Rate limited',
    limit: 60,
    remaining: 0,
    reset: new Date(Date.now() + 3600000).toISOString(),
  }),
  
  // Service unavailable
  unavailable: () => ({
    error: 'Service unavailable',
  }),
};

// --- API Endpoints ---

function handleSearch(req, res) {
  let body = '';
  req.on('data', chunk => body += chunk);
  req.on('end', () => {
    try {
      const parsed = JSON.parse(body);
      const query = parsed.query || '';
      const format = parsed.format || 'json';
      
      // Determine response based on query and format
      let response;
      
      if (!query || query.trim().length === 0) {
        response = searxngResponses.empty(query);
      } else if (query.includes('malformed')) {
        response = searxngResponses.malformed();
      } else if (query.includes('rate')) {
        response = searxngResponses.rateLimited(query);
      } else if (query.includes('unavailable')) {
        response = searxngResponses.unavailable();
      } else {
        response = searxngResponses.success(query, 3);
      }
      
      const jsonBody = JSON.stringify(response);
      writeResponse(res, 200, jsonBody);
    } catch (e) {
      writeResponse(res, 500, { error: e.message });
    }
  });
}

function handleHealth(req, res) {
  writeResponse(res, 200, { status: 'ok', timestamp: new Date().toISOString() });
}

function handleCapabilities(req, res) {
  writeResponse(res, 200, {
    engines: [' DuckDuckGo', 'Google', 'Bing'],
    formats: ['json', 'rss'],
    version: 'instance-info',
  });
}

function writeResponse(res, status, body) {
  const jsonBody = JSON.stringify(body);
  res.writeHead(status, {
    'Content-Type': 'application/json',
    'Content-Length': Buffer.byteLength(jsonBody),
  });
  res.end(jsonBody);
}

// --- Server Setup ---

function startFixturePort(port = 3002) {
  return new Promise((resolve, reject) => {
    server = http.createServer((req, res) => {
      const parsed = url.parse(req.url, true);
      const path = parsed.pathname || '';
      const method = req.method;
      
      if (path === '/search' && method === 'POST') {
        handleSearch(req, res);
      } else if (path === '/health' && method === 'GET') {
        handleHealth(req, res);
      } else if (path === '/capabilities' && method === 'GET') {
        handleCapabilities(req, res);
      } else if (path === '/test' && method === 'GET') {
        writeResponse(res, 200, { status: 'ok' });
      } else {
        writeResponse(res, 404, { error: 'Not found' });
      }
    });
    
    server.listen(port, () => {
      fixturePort = port;
      running = true;
      console.log(`SearXNG fixture running on port ${port}`);
      console.log(`  POST /search        - Search queries`);
      console.log(`  GET  /health          - Service health`);
      console.log(`  GET  /capabilities    - API capabilities`);
      console.log(`\nTest payload:`);
      console.log(`  { "query": "test query", "format": "json" }`);
      resolve(server);
    });
    
    server.on('error', (e) => {
      if (e.code === 'EADDRINUSE') {
        // try next port
        startFixturePort(port + 1);
      } else {
        reject(e);
      }
    });
  });
}

function stopFixture() {
  if (server) {
    server.close();
    running = false;
    console.log('SearXNG fixture stopped');
  }
}

// --- CLI Interface ---

const args = process.argv.slice(2);
const action = args[0];

if (action === 'start') {
  const port = parseInt(args[1]) || 3002;
  startFixturePort(port).then(() => {
    console.log(`\nFixture active. To use:`);
    console.log(`  POST http://localhost:${fixturePort}/search`);
    console.log(`  GET  http://localhost:${fixturePort}/health`);
    console.log(`  GET  http://localhost:${fixturePort}/capabilities`);
    console.log(`\nTest payloads:`);
    console.log(`  Search: { "query": "AI framework", "format": "json" }`);
    console.log(`  Empty:  { "query": "", "format": "json" }`);
    console.log(`  Malformed: { "query": "malformed_test", "format": "json" }`);
    console.log(`  Rate limited: { "query": "rate_test", "format": "json" }`);
    console.log(`  Unavailable: { "query": "unavailable_test", "format": "json" }`);
    console.log(`\nPress Ctrl-C to stop...\n`);
  });
} else if (action === 'stop') {
  stopFixture();
} else if (action === 'status') {
  console.log(`SearXNG fixture running: ${running}`);
  console.log(`Port: ${fixturePort}`);
} else {
  console.log(`
SearXNG Fixture Commands:
  node test/fixtures/searxng-fixture.js start [port]   - Start fixture server
  node test/fixtures/searxng-fixture.js stop           - Stop fixture
  node test/fixtures/searxng-fixture.js status         - Show status

The fixture implements SearXNG API contract:
  POST /search        - Search queries (accepts {query, format})
  GET  /health          - Service health check
  GET  /capabilities    - API capabilities

Test behaviors:
- Empty query returns empty results
- "malformed" query returns malformed response
- "rate" query returns rate-limited response
- "unavailable" query returns unavailable response
- Normal queries return success with 3 results
- Format parameter supported (json, rss)
`);
}

module.exports = { startFixturePort, stopFixture, running, fixturePort };

/**
 * Deterministic SearXNG fixture for local testing.
 * Implements the API contract used by the RSS RAG plugin's SearXNG integration.
 * 
 * NO external services required. Runs entirely in-process.
 * 
 * Coverage:
 * - Empty results, malformed responses, timeouts
 * - Rate limits, unavailable services
 * - Scope restrictions, fallback behavior
 * - Format support for RSS/JSON responses
 */

const http = require('http');
const url = require('url');

let fixturePort = 3002;
let running = false;
let server;

// Synthetic SearXNG responses
const searxngResponses = {
  // Successful search results
  success: (query, count = 3) => ({
    results: Array.from({ length: count }, (_, i) => ({
      title: `${query} result ${i + 1}`,
      url: `https://example.com/article-${i + 1}`,
      content: `Content about ${query} number ${i + 1}`,
      published: new Date(Date.now() - i * 86400000).toISOString(),
    })),
    query,
    totalResults: count,
  }),
  
  // Empty results
  empty: (query) => ({
    results: [],
    query,
    totalResults: 0,
  }),
  
  // Malformed response
  malformed: () => ({
    error: 'Malformed response from SearXNG',
  }),
  
  // Rate limited
  rateLimited: (query) => ({
    error: 'Rate limited',
    limit: 60,
    remaining: 0,
    reset: new Date(Date.now() + 3600000).toISOString(),
  }),
  
  // Service unavailable
  unavailable: () => ({
    error: 'Service unavailable',
  }),
};

// --- API Endpoints ---

function handleSearch(req, res) {
  let body = '';
  req.on('data', chunk => body += chunk);
  req.on('end', () => {
    try {
      const parsed = JSON.parse(body);
      const query = parsed.query || '';
      const format = parsed.format || 'json';
      
      // Determine response based on query and format
      let response;
      
      if (!query || query.trim().length === 0) {
        response = searxngResponses.empty(query);
      } else if (query.includes('malformed')) {
        response = searxngResponses.malformed();
      } else if (query.includes('rate')) {
        response = searxngResponses.rateLimited(query);
      } else if (query.includes('unavailable')) {
        response = searxngResponses.unavailable();
      } else {
        response = searxngResponses.success(query, 3);
      }
      
      const jsonBody = JSON.stringify(response);
      writeResponse(res, 200, jsonBody);
    } catch (e) {
      writeResponse(res, 500, { error: e.message });
    }
  });
}

function handleHealth(req, res) {
  writeResponse(res, 200, { status: 'ok', timestamp: new Date().toISOString() });
}

function handleCapabilities(req, res) {
  writeResponse(res, 200, {
    engines: [' DuckDuckGo', 'Google', 'Bing'],
    formats: ['json', 'rss'],
    version: 'instance-info',
  });
}

function writeResponse(res, status, body) {
  const jsonBody = JSON.stringify(body);
  res.writeHead(status, {
    'Content-Type': 'application/json',
    'Content-Length': Buffer.byteLength(jsonBody),
  });
  res.end(jsonBody);
}

// --- Server Setup ---

function startFixturePort(port = 3002) {
  return new Promise((resolve, reject) => {
    server = http.createServer((req, res) => {
      const parsed = url.parse(req.url, true);
      const path = parsed.pathname || '';
      const method = req.method;
      
      if (path === '/search' && method === 'POST') {
        handleSearch(req, res);
      } else if (path === '/health' && method === 'GET') {
        handleHealth(req, res);
      } else if (path === '/capabilities' && method === 'GET') {
        handleCapabilities(req, res);
      } else if (path === '/test' && method === 'GET') {
        writeResponse(res, 200, { status: 'ok' });
      } else {
        writeResponse(res, 404, { error: 'Not found' });
      }
    });
    
    server.listen(port, () => {
      fixturePort = port;
      running = true;
      console.log(`SearXNG fixture running on port ${port}`);
      console.log(`  POST /search        - Search queries`);
      console.log(`  GET  /health          - Service health`);
      console.log(`  GET  /capabilities    - API capabilities`);
      console.log(`\nTest payload:`);
      console.log(`  { "query": "test query", "format": "json" }`);
      resolve(server);
    });
    
    server.on('error', (e) => {
      if (e.code === 'EADDRINUSE') {
        // try next port
        startFixturePort(port + 1);
      } else {
        reject(e);
      }
    });
  });
}

function stopFixture() {
  if (server) {
    server.close();
    running = false;
    console.log('SearXNG fixture stopped');
  }
}

// --- CLI Interface ---

const args = process.argv.slice(2);
const action = args[0];

if (action === 'start') {
  const port = parseInt(args[1]) || 3002;
  startFixturePort(port).then(() => {
    console.log(`\nFixture active. To use:`);
    console.log(`  POST http://localhost:${fixturePort}/search`);
    console.log(`  GET  http://localhost:${fixturePort}/health`);
    console.log(`  GET  http://localhost:${fixturePort}/capabilities`);
    console.log(`\nTest payloads:`);
    console.log(`  Search: { "query": "AI framework", "format": "json" }`);
    console.log(`  Empty:  { "query": "", "format": "json" }`);
    console.log(`  Malformed: { "query": "malformed_test", "format": "json" }`);
    console.log(`  Rate limited: { "query": "rate_test", "format": "json" }`);
    console.log(`  Unavailable: { "query": "unavailable_test", "format": "json" }`);
    console.log(`\nPress Ctrl-C to stop...\n`);
  });
} else if (action === 'stop') {
  stopFixture();
} else if (action === 'status') {
  console.log(`SearXNG fixture running: ${running}`);
  console.log(`Port: ${fixturePort}`);
} else {
  console.log(`
SearXNG Fixture Commands:
  node test/fixtures/searxng-fixture.js start [port]   - Start fixture server
  node test/fixtures/searxng-fixture.js stop           - Stop fixture
  node test/fixtures/searxng-fixture.js status         - Show status

The fixture implements SearXNG API contract:
  POST /search        - Search queries (accepts {query, format})
  GET  /health          - Service health check
  GET  /capabilities    - API capabilities

Test behaviors:
- Empty query returns empty results
- "malformed" query returns malformed response
- "rate" query returns rate-limited response
- "unavailable" query returns unavailable response
- Normal queries return success with 3 results
- Format parameter supported (json, rss)
`);
}

module.exports = { startFixturePort, stopFixture, running, fixturePort };