bucketNamespace.ts

import * as core from 'aws-cdk-lib';
import { aws_s3 as s3 } from 'aws-cdk-lib';
import * as constructs from 'constructs';

export class BucketNamespace extends core.Mixin {
  static accountRegional(): BucketNamespace {
    return new BucketNamespace('account-regional');
  }
  static global(): BucketNamespace {
    return new BucketNamespace('global');
  }
  private constructor(private readonly namespace: 'global' | 'account-regional') {
    super();
  }
  supports(construct: constructs.IConstruct): construct is s3.CfnBucket {
    return construct instanceof s3.CfnBucket;
  }
  applyTo(construct: constructs.IConstruct): void {
    const cfnBucket = construct as s3.CfnBucket;
    cfnBucket.addPropertyOverride('BucketNamespace', this.namespace);
    if (this.namespace === 'account-regional' && cfnBucket.bucketName) {
      const stack = core.Stack.of(construct);
      const expectedSuffix = `-${stack.account}-${stack.region}-an`;
      const suffixPattern = /-\d{12}-[a-z0-9-]+-an$/;
      const name = cfnBucket.bucketName as string;

      if (name.endsWith(expectedSuffix)) {
        return;
      }
      if (suffixPattern.test(name)) {
        throw new Error(
          `Bucket name '${name}' has an account-regional suffix that does not match this stack's account/region. Expected suffix: '${expectedSuffix}'`,
        );
      }
      cfnBucket.bucketName = core.Fn.sub(
        '${BucketName}-${AWS::AccountId}-${AWS::Region}-an',
        { BucketName: name },
      );
    }
  }
}