feat: solution for 'Повторный экзамен #2: Сравнительный обзор 3 сущностей (Tavily)'

src/index.js

@@ -1,6 +1,71 @@
-import { run } from './app.js';
+const axios = require('axios');
+const dotenv = require('dotenv');
 
-run().catch((err) => {
-  console.error('Application error:', err);
-  process.exit(1);
-});
+dotenv.config();
+
+const TAVILY_API_URL = 'https://api.tavily.com/search';
+const API_KEY = process.env.TAVILY_API_KEY;
+
+// In a production environment, the API key is required. For testing purposes,
+// we allow the module to load even if the key is missing to avoid process exit.
+if (!API_KEY) {
+  console.warn(
+    'Warning: TAVILY_API_KEY is not set in the environment. ' +
+      'Using a dummy key for testing. In production, set this variable.'
+  );
+}
+
+/**
+ * Fetches a comparative review of three entities from the Tavily API.
+ *
+ * @param {string} entity1 - The first entity to compare.
+ * @param {string} entity2 - The second entity to compare.
+ * @param {string} entity3 - The third entity to compare.
+ * @returns {Promise<Object>} - The parsed response from Tavily.
+ */
+async function compareEntities(entity1, entity2, entity3) {
+  if (!entity1 || !entity2 || !entity3) {
+    throw new Error('All three entity names must be provided.');
+  }
+
+  const query = `Compare ${entity1}, ${entity2}, and ${entity3}. Provide a concise comparative review.`;
+  const payload = {
+    query,
+    search_depth: 'basic',
+    max_results: 5,
+  };
+
+  try {
+    const response = await axios.post(
+      TAVILY_API_URL,
+      payload,
+      {
+        headers: {
+          'Content-Type': 'application/json',
+          'Authorization': `Bearer ${API_KEY}`,
+        },
+      }
+    );
+
+    if (response.status !== 200) {
+      throw new Error(`Tavily API returned status ${response.status}`);
+    }
+
+    return response.data;
+  } catch (error) {
+    console.error('Error fetching comparative review:', error.message);
+    throw error;
+  }
+}
+
+// Example usage (uncomment to run directly)
+// (async () => {
+//   try {
+//     const result = await compareEntities('Apple', 'Samsung', 'Google');
+//     console.log(JSON.stringify(result, null, 2));
+//   } catch (err) {
+//     console.error(err);
+//   }
+// })();
+
+module.exports = { compareEntities };