import * as cdk from 'aws-cdk-lib';
import { Construct } from 'constructs';
import * as s3 from 'aws-cdk-lib/aws-s3';
import { bedrock } from '@cdklabs/generative-ai-cdk-constructs';

export interface KnowledgeBaseProps {
  accountId: string;
  region: string;
}

export class KnowledgeBaseConstruct extends Construct {
  public readonly knowledgeBase: bedrock.VectorKnowledgeBase;
  public readonly dataSource: bedrock.S3DataSource;
  public readonly docsBucket: s3.Bucket;

  constructor(scope: Construct, id: string, props: KnowledgeBaseProps) {
    super(scope, id);

    // S3 bucket for SA8000 docs, SOPs, and employee handbook
    this.docsBucket = new s3.Bucket(this, 'DocsBucket', {
      bucketName: `seahaven-kb-docs-${props.accountId}`,
      encryption: s3.BucketEncryption.S3_MANAGED,
      blockPublicAccess: s3.BlockPublicAccess.BLOCK_ALL,
      versioned: true,
      removalPolicy: cdk.RemovalPolicy.RETAIN,
    });

    // VectorKnowledgeBase from @cdklabs/generative-ai-cdk-constructs handles:
    // - AOSS collection with correct encryption/network/access policies
    // - IAM execution role
    // - kNN vector index creation via built-in custom resource
    // - Bedrock Knowledge Base creation once the index is ready
    this.knowledgeBase = new bedrock.VectorKnowledgeBase(this, 'KnowledgeBase', {
      embeddingsModel: bedrock.BedrockFoundationModel.TITAN_EMBED_TEXT_V2_1024,
      name: 'seahaven-kb',
      description: 'SA8000 compliance docs, SOPs, and employee handbook',
      instruction: 'Use this knowledge base to answer questions about Sea Haven Industries company policies, SOPs, SA8000 social accountability compliance requirements, approved vendor lists, and the employee handbook.',
    });

    // S3 data source — chunking configured via ChunkingStrategy.fixedSize()
    this.dataSource = new bedrock.S3DataSource(this, 'S3DataSource', {
      bucket: this.docsBucket,
      knowledgeBase: this.knowledgeBase,
      dataSourceName: 'seahaven-s3-docs',
      chunkingStrategy: bedrock.ChunkingStrategy.fixedSize({
        maxTokens: 512,
        overlapPercentage: 20,
      }),
    });
  }
}