/**
 * Creates the kNN vector index in the OpenSearch Serverless collection.
 *
 * Run this ONCE after `cdk deploy` creates the AOSS collection but BEFORE
 * triggering a Bedrock Knowledge Base sync/ingestion job.
 *
 * Usage:
 *   npx ts-node scripts/create-aoss-index.ts <collection-endpoint>
 *
 * The collection endpoint is printed as a stack output after deploy:
 *   npx cdk deploy --outputs-file outputs.json
 *   cat outputs.json
 *
 * Requirements:
 *   npm install --save-dev @opensearch-project/opensearch aws4 ts-node typescript
 *   AWS credentials must have aoss:APIAccessAll on the collection.
 */

import { Client } from '@opensearch-project/opensearch';
import { AwsSigv4Signer } from '@opensearch-project/opensearch/aws';
import { defaultProvider } from '@aws-sdk/credential-provider-node';

const INDEX_NAME = 'seahaven-kb-index';

// Field names must match exactly what's configured in knowledge-base.ts
const INDEX_BODY = {
  settings: {
    'index.knn': true,
  },
  mappings: {
    properties: {
      // Titan Embed Text v2 with 1024 dimensions
      'bedrock-knowledge-base-default-vector': {
        type: 'knn_vector',
        dimension: 1024,
        method: {
          name: 'hnsw',
          space_type: 'l2',
          engine: 'faiss',
          parameters: { ef_construction: 512, m: 16 },
        },
      },
      AMAZON_BEDROCK_TEXT_CHUNK: { type: 'text' },
      AMAZON_BEDROCK_METADATA: { type: 'text', index: false },
    },
  },
};

async function main(): Promise<void> {
  const endpoint = process.argv[2];
  if (!endpoint) {
    console.error('Usage: npx ts-node scripts/create-aoss-index.ts <collection-endpoint>');
    console.error('Example: npx ts-node scripts/create-aoss-index.ts https://abc123.us-east-1.aoss.amazonaws.com');
    process.exit(1);
  }

  const client = new Client({
    ...AwsSigv4Signer({
      region: 'us-east-1',
      service: 'aoss',
      getCredentials: defaultProvider(),
    }),
    node: endpoint,
  });

  console.log(`Creating index "${INDEX_NAME}" on ${endpoint} …`);

  const exists = await client.indices.exists({ index: INDEX_NAME });
  if (exists.statusCode === 200) {
    console.log(`Index "${INDEX_NAME}" already exists — nothing to do.`);
    return;
  }

  const res = await client.indices.create({
    index: INDEX_NAME,
    body: INDEX_BODY,
  });

  console.log('Index created:', JSON.stringify(res.body, null, 2));
  console.log('\nNext step: trigger a sync from the Bedrock console or run:');
  console.log('  aws bedrock-agent start-ingestion-job --knowledge-base-id <KB_ID> --data-source-id <DS_ID>');
}

main().catch((err) => {
  console.error('Failed to create index:', err);
  process.exit(1);
});