import * as cdk from 'aws-cdk-lib';
import { Construct } from 'constructs';
import * as lambda from 'aws-cdk-lib/aws-lambda';
import * as lambdaNodejs from 'aws-cdk-lib/aws-lambda-nodejs';
import * as logs from 'aws-cdk-lib/aws-logs';
import * as s3 from 'aws-cdk-lib/aws-s3';
import * as dynamodb from 'aws-cdk-lib/aws-dynamodb';
import * as kms from 'aws-cdk-lib/aws-kms';
import * as ssm from 'aws-cdk-lib/aws-ssm';
import * as events from 'aws-cdk-lib/aws-events';
import * as targets from 'aws-cdk-lib/aws-events-targets';
import * as iam from 'aws-cdk-lib/aws-iam';
import * as path from 'path';

export interface PoSyncProps {
  region: string;
  kbDocsBucket: s3.Bucket;
  knowledgeBaseId: string;
  dataSourceId: string;
}

export class PoSyncConstruct extends Construct {
  public readonly syncLambda: lambdaNodejs.NodejsFunction;

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

    // Import the purchase-orders DynamoDB table (owned by po-ingest stack)
    const poTable = dynamodb.Table.fromTableName(
      this, 'PurchaseOrdersTable', 'purchase-orders',
    );

    // Lambda — scans purchase-orders table, uploads markdown to S3, triggers KB ingestion
    this.syncLambda = new lambdaNodejs.NodejsFunction(this, 'SyncLambda', {
      functionName: 'seahaven-po-sync',
      entry: path.join(__dirname, '../../lambda/po-sync/index.ts'),
      runtime: lambda.Runtime.NODEJS_24_X,
      architecture: lambda.Architecture.ARM_64,
      logRetention: logs.RetentionDays.TWO_MONTHS,
      memorySize: 512,
      timeout: cdk.Duration.minutes(15),
      environment: {
        PO_TABLE: poTable.tableName,
        KB_BUCKET_NAME: props.kbDocsBucket.bucketName,
        KNOWLEDGE_BASE_ID: props.knowledgeBaseId,
        DATA_SOURCE_ID: props.dataSourceId,
        REGION: props.region,
      },
    });

    // Grant read access to the purchase-orders table
    poTable.grantReadData(this.syncLambda);

    // purchase-orders is SSE-encrypted with the shared customer-managed CMK
    // (INFRA-95 / M-3). The table is imported by name, so grantReadData does not
    // add KMS perms — grant kms:Decrypt explicitly or scans fail with
    // AccessDenied. (CMK key policy delegates to IAM via kms:ViaService.)
    const dynamodbCmk = kms.Key.fromKeyArn(
      this,
      'DynamoDbCmk',
      ssm.StringParameter.valueForStringParameter(this, '/seahaven/dynamodb/cmk-arn'),
    );
    dynamodbCmk.grantDecrypt(this.syncLambda);

    // Grant read/write to the KB docs bucket (read to list+delete old, write new)
    props.kbDocsBucket.grantReadWrite(this.syncLambda);

    // Allow Lambda to start a Bedrock KB ingestion job
    this.syncLambda.addToRolePolicy(
      new iam.PolicyStatement({
        actions: ['bedrock:StartIngestionJob'],
        resources: [
          `arn:aws:bedrock:${props.region}:*:knowledge-base/${props.knowledgeBaseId}`,
        ],
      }),
    );

    // EventBridge rule — fires daily at 02:00 UTC
    const dailyRule = new events.Rule(this, 'DailySyncRule', {
      ruleName: 'seahaven-po-daily-sync',
      description: 'Daily purchase-orders → KB sync at 02:00 UTC',
      schedule: events.Schedule.cron({ minute: '0', hour: '2' }),
    });

    dailyRule.addTarget(new targets.LambdaFunction(this.syncLambda));
  }
}