index.js

import dotenv from 'dotenv';

// Load environment variables
dotenv.config();

const {
  SOURCE_APP_SEARCH_URL,
  SOURCE_APP_SEARCH_API_KEY,
  DEST_APP_SEARCH_URL,
  DEST_APP_SEARCH_API_KEY,
  SOURCE_ENGINE_NAME,
  DEST_ENGINE_NAME
} = process.env;

// Validate env vars
if (!SOURCE_APP_SEARCH_URL || !SOURCE_APP_SEARCH_API_KEY ||
    !DEST_APP_SEARCH_URL || !DEST_APP_SEARCH_API_KEY ||
    !SOURCE_ENGINE_NAME || !DEST_ENGINE_NAME) {
  console.error('❌ Missing required environment variables.');
  process.exit(1);
}

const BATCH_SIZE = 100; // App Search allows up to 100 docs per batch

// Function to fetch documents from the source engine
async function fetchDocumentsFromSource(page) {
  const url = `${SOURCE_APP_SEARCH_URL}/api/as/v1/engines/${SOURCE_ENGINE_NAME}/search`;
  const body = {
    query: '',
    page: {
      size: BATCH_SIZE,
      current: page
    }
  };

  console.log(`⏳ Fetching documents from source engine, page ${page}...`);

  const response = await fetch(url, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'Authorization': `Bearer ${SOURCE_APP_SEARCH_API_KEY}`
    },
    body: JSON.stringify(body)
  });

  if (!response.ok) {
    throw new Error(`Error fetching documents from source engine: ${response.statusText}`);
  }

  const data = await response.json();
  console.log(`📄 Fetched ${data.results.length} documents from source engine (Page ${page})`);
  return data;
}

// Function to index an individual document into the destination engine
async function indexDocumentToDest(doc) {
  const url = `${DEST_APP_SEARCH_URL}/api/as/v1/engines/${DEST_ENGINE_NAME}/documents`;
  console.log(`📤 Indexing document with ID: ${doc.id.raw} to destination engine...`);
  delete doc._meta
  delete doc.id

  const indexDoc = Object.fromEntries(
    Object.entries(doc).map(([key, value]) => [key, value.raw])
  );


  const response = await fetch(url, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'Authorization': `Bearer ${DEST_APP_SEARCH_API_KEY}`
    },
    body: JSON.stringify(indexDoc) // Send the document as is
  });

  if (!response.ok) {
    throw new Error(`Error indexing document to destination engine: ${response.statusText}`);
  }

  const responseData = await response.json();
  console.log(`✅ Successfully indexed document with ID: ${responseData[0].id}`);
  return responseData;
}

async function copyAppSearchEngine() {
  let currentPage = 1;
  let totalCopied = 0;
  let done = false;

  while (!done) {
    try {
      // Fetch documents from the source engine
      const searchResponse = await fetchDocumentsFromSource(currentPage);

      if (searchResponse.results.length === 0) {
        console.log('✅ No more documents to copy.');
        done = true;
        break;
      }

      // For each document, index it individually into the destination engine
      for (const doc of searchResponse.results) {
        console.log(`🔍 Processing document with ID: ${doc.id.raw}`);
        await indexDocumentToDest(doc);
        totalCopied++;
      }

      console.log(`📄 Copied ${totalCopied} documents so far...`);
      currentPage++;
    } catch (error) {
      console.error('❌ Error during copy:', error.message);
      process.exit(1);
    }
  }

  console.log('✅ Finished copying all documents!');
}

copyAppSearchEngine();