/**
 * Comprehensive Bulk Indexer Example
 *
 * Demonstrates high-throughput document ingestion with adaptive batching
 */

import {
  createConfig,
  ElasticsearchConnectionManager,
  LogLevel,
  BulkIndexer,
  type BulkProgress,
  type BulkBatchResult,
} from '../../index.js';

interface Product {
  id: string;
  name: string;
  description: string;
  category: string;
  price: number;
  stock: number;
  createdAt: Date;
}

async function main() {
  console.log('=== Bulk Indexer Example ===\n');

  // ============================================================================
  // Step 1: Configuration
  // ============================================================================

  console.log('Step 1: Configuring Elasticsearch connection...');
  const config = createConfig()
    .fromEnv()
    .nodes(process.env.ELASTICSEARCH_URL || 'http://localhost:9200')
    .basicAuth(
      process.env.ELASTICSEARCH_USERNAME || 'elastic',
      process.env.ELASTICSEARCH_PASSWORD || 'changeme'
    )
    .timeout(30000)
    .retries(3)
    .logLevel(LogLevel.INFO)
    .enableMetrics(true)
    .build();

  // ============================================================================
  // Step 2: Initialize Connection
  // ============================================================================

  console.log('Step 2: Initializing connection manager...');
  const connectionManager = ElasticsearchConnectionManager.getInstance(config);
  await connectionManager.initialize();
  console.log('✓ Connection manager initialized\n');

  // ============================================================================
  // Step 3: Basic Bulk Indexing
  // ============================================================================

  console.log('Step 3: Basic bulk indexing...');
  const basicIndexer = new BulkIndexer({
    batchingStrategy: 'fixed',
    batchSize: 100,
    flushIntervalMs: 2000,
    workers: 2,
  });

  await basicIndexer.start();

  // Index documents
  const startTime = Date.now();
  for (let i = 1; i <= 500; i++) {
    await basicIndexer.index('products-basic', `product-${i}`, {
      id: `product-${i}`,
      name: `Product ${i}`,
      description: `Description for product ${i}`,
      category: `Category ${(i % 5) + 1}`,
      price: Math.random() * 1000,
      stock: Math.floor(Math.random() * 100),
      createdAt: new Date(),
    });
  }

  await basicIndexer.flush();
  await basicIndexer.stop();

  const duration = Date.now() - startTime;
  const stats = basicIndexer.getStats();
  console.log('✓ Basic indexing complete');
  console.log(`  Indexed: ${stats.totalSuccessful} documents`);
  console.log(`  Duration: ${duration}ms`);
  console.log(`  Throughput: ${((stats.totalSuccessful / duration) * 1000).toFixed(0)} docs/sec`);
  console.log(`  Avg batch size: ${stats.avgBatchSize.toFixed(0)}`);
  console.log(`  Avg batch duration: ${stats.avgBatchDurationMs.toFixed(0)}ms`);
  console.log();

  // ============================================================================
  // Step 4: Adaptive Batching
  // ============================================================================

  console.log('Step 4: Adaptive batching...');
  const adaptiveIndexer = new BulkIndexer({
    batchingStrategy: 'adaptive',
    minBatchSize: 50,
    maxBatchSize: 500,
    flushIntervalMs: 3000,
    workers: 3,
    onProgress: (progress: BulkProgress) => {
      if (progress.totalProcessed % 200 === 0 && progress.totalProcessed > 0) {
        console.log(
          `  Progress: ${progress.totalProcessed}/${progress.totalSubmitted} ` +
            `(${progress.operationsPerSecond} ops/sec, ${progress.queueSize} queued)`
        );
      }
    },
  });

  await adaptiveIndexer.start();

  // Index larger dataset
  console.log('  Indexing 1000 documents with adaptive batching...');
  for (let i = 1; i <= 1000; i++) {
    await adaptiveIndexer.index('products-adaptive', `product-${i}`, {
      id: `product-${i}`,
      name: `Adaptive Product ${i}`,
      description: `Description for adaptive product ${i}`,
      category: `Category ${(i % 10) + 1}`,
      price: Math.random() * 2000,
      stock: Math.floor(Math.random() * 200),
      createdAt: new Date(),
    });
  }

  await adaptiveIndexer.flush();
  await adaptiveIndexer.stop();

  const adaptiveStats = adaptiveIndexer.getStats();
  console.log('✓ Adaptive indexing complete');
  console.log(`  Indexed: ${adaptiveStats.totalSuccessful} documents`);
  console.log(`  Avg batch size: ${adaptiveStats.avgBatchSize.toFixed(0)} (adapted based on performance)`);
  console.log(`  Avg ops/sec: ${adaptiveStats.avgOpsPerSecond.toFixed(0)}`);
  console.log();

  // ============================================================================
  // Step 5: Progress Callbacks
  // ============================================================================

  console.log('Step 5: Using progress callbacks...');
  let lastProgress = 0;
  const progressIndexer = new BulkIndexer({
    batchSize: 100,
    workers: 4,
    onProgress: (progress: BulkProgress) => {
      const percent = (progress.totalProcessed / progress.totalSubmitted) * 100;
      if (percent - lastProgress >= 20) {
        console.log(`  ${percent.toFixed(0)}% complete (${progress.totalProcessed}/${progress.totalSubmitted})`);
        if (progress.estimatedTimeRemainingMs !== undefined) {
          console.log(`    ETA: ${(progress.estimatedTimeRemainingMs / 1000).toFixed(1)}s`);
        }
        lastProgress = percent;
      }
    },
    onBatchSuccess: (result: BulkBatchResult) => {
      if (result.failed > 0) {
        console.log(`    Batch completed: ${result.successful} ok, ${result.failed} failed`);
      }
    },
  });

  await progressIndexer.start();

  for (let i = 1; i <= 500; i++) {
    await progressIndexer.index('products-progress', `product-${i}`, {
      id: `product-${i}`,
      name: `Progress Product ${i}`,
      description: `Description ${i}`,
      category: `Category ${(i % 3) + 1}`,
      price: Math.random() * 500,
      stock: Math.floor(Math.random() * 50),
      createdAt: new Date(),
    });
  }

  await progressIndexer.flush();
  await progressIndexer.stop();
  console.log('✓ Progress tracking complete\n');

  // ============================================================================
  // Step 6: Backpressure Handling
  // ============================================================================

  console.log('Step 6: Demonstrating backpressure handling...');
  const backpressureIndexer = new BulkIndexer({
    batchSize: 50,
    maxQueueSize: 200,
    flushIntervalMs: 1000,
    workers: 1, // Single worker to create backpressure
  });

  await backpressureIndexer.start();

  console.log('  Submitting operations rapidly...');
  let backpressureHits = 0;
  for (let i = 1; i <= 300; i++) {
    const backpressure = backpressureIndexer.getBackpressure();
    if (backpressure.active && i % 50 === 0) {
      console.log(
        `    Backpressure detected: ${backpressure.queueUtilization.toFixed(0)}% queue utilization ` +
          `(waiting ${backpressure.recommendedWaitMs}ms)`
      );
      backpressureHits++;
    }

    await backpressureIndexer.index('products-backpressure', `product-${i}`, {
      id: `product-${i}`,
      name: `Backpressure Product ${i}`,
      description: `Test ${i}`,
      category: `Cat ${i % 2}`,
      price: i * 10,
      stock: i,
      createdAt: new Date(),
    });
  }

  await backpressureIndexer.flush();
  await backpressureIndexer.stop();
  console.log('✓ Backpressure handling demonstrated');
  console.log(`  Backpressure events: ${backpressureHits}`);
  console.log();

  // ============================================================================
  // Step 7: Mixed Operations
  // ============================================================================

  console.log('Step 7: Mixed operations (index, update, delete)...');
  const mixedIndexer = new BulkIndexer({
    batchSize: 50,
    workers: 2,
  });

  await mixedIndexer.start();

  // Index documents
  for (let i = 1; i <= 100; i++) {
    await mixedIndexer.index('products-mixed', `product-${i}`, {
      id: `product-${i}`,
      name: `Mixed Product ${i}`,
      description: `Original description ${i}`,
      category: `Category ${(i % 5) + 1}`,
      price: i * 100,
      stock: i * 10,
      createdAt: new Date(),
    });
  }

  // Update some documents
  for (let i = 1; i <= 30; i++) {
    await mixedIndexer.update<Product>('products-mixed', `product-${i}`, {
      price: i * 150, // Updated price
      stock: i * 15, // Updated stock
    });
  }

  // Delete some documents
  for (let i = 91; i <= 100; i++) {
    await mixedIndexer.delete('products-mixed', `product-${i}`);
  }

  await mixedIndexer.flush();

  const mixedStats = mixedIndexer.getStats();
  await mixedIndexer.stop();

  console.log('✓ Mixed operations complete');
  console.log(`  Total operations: ${mixedStats.totalProcessed}`);
  console.log(`    Index: 100, Update: 30, Delete: 10`);
  console.log(`  Successful: ${mixedStats.totalSuccessful}`);
  console.log(`  Failed: ${mixedStats.totalFailed}`);
  console.log();

  // ============================================================================
  // Step 8: Dead-Letter Queue
  // ============================================================================

  console.log('Step 8: Dead-letter queue for failed operations...');
  const dlqIndexer = new BulkIndexer({
    batchSize: 50,
    maxRetries: 2,
    retryDelayMs: 500,
    enableDeadLetterQueue: true,
    deadLetterIndex: 'failed-operations-{now/d}',
    workers: 2,
  });

  await dlqIndexer.start();

  // Index valid documents
  for (let i = 1; i <= 50; i++) {
    await dlqIndexer.index('products-dlq', `product-${i}`, {
      id: `product-${i}`,
      name: `DLQ Product ${i}`,
      description: `Description ${i}`,
      category: `Cat ${i % 3}`,
      price: i * 50,
      stock: i * 5,
      createdAt: new Date(),
    });
  }

  await dlqIndexer.flush();

  // Wait a bit for any retries
  await new Promise((resolve) => setTimeout(resolve, 2000));

  const dlqStats = dlqIndexer.getStats();
  await dlqIndexer.stop();

  console.log('✓ Dead-letter queue test complete');
  console.log(`  Successful: ${dlqStats.totalSuccessful}`);
  console.log(`  Failed (after retries): ${dlqStats.totalFailed}`);
  console.log(`  Sent to DLQ: ${dlqStats.totalDeadLettered}`);
  console.log();

  // ============================================================================
  // Step 9: Statistics Summary
  // ============================================================================

  console.log('Step 9: Final statistics summary...\n');

  const finalStats = dlqIndexer.getStats();
  console.log('Sample Indexer Statistics:');
  console.log(`  Total submitted: ${finalStats.totalSubmitted}`);
  console.log(`  Total processed: ${finalStats.totalProcessed}`);
  console.log(`  Total successful: ${finalStats.totalSuccessful}`);
  console.log(`  Total failed: ${finalStats.totalFailed}`);
  console.log(`  Total dead-lettered: ${finalStats.totalDeadLettered}`);
  console.log(`  Total batches: ${finalStats.totalBatches}`);
  console.log(`  Avg batch size: ${finalStats.avgBatchSize.toFixed(1)}`);
  console.log(`  Avg batch duration: ${finalStats.avgBatchDurationMs.toFixed(1)}ms`);
  console.log(`  Avg ops/sec: ${finalStats.avgOpsPerSecond.toFixed(0)}`);
  console.log();

  // ============================================================================
  // Step 10: Cleanup
  // ============================================================================

  console.log('Step 10: Cleanup...');
  await connectionManager.destroy();
  console.log('✓ Connection closed\n');

  console.log('=== Bulk Indexer Example Complete ===');
  console.log('\nKey Features Demonstrated:');
  console.log('  ✓ Fixed batch size strategy');
  console.log('  ✓ Adaptive batching (adjusts based on performance)');
  console.log('  ✓ Progress callbacks with ETA');
  console.log('  ✓ Backpressure handling');
  console.log('  ✓ Mixed operations (index, update, delete)');
  console.log('  ✓ Dead-letter queue for failed operations');
  console.log('  ✓ Automatic retries with exponential backoff');
  console.log('  ✓ Parallel workers');
  console.log('  ✓ Comprehensive statistics');
}

// Run the example
main().catch((error) => {
  console.error('Example failed:', error);
  process.exit(1);
});