import { Construct } from 'constructs';
import * as ec2 from 'aws-cdk-lib/aws-ec2'
import * as rds from "aws-cdk-lib/aws-rds";
import * as cdk from 'aws-cdk-lib';

interface RdsProps {
  vpc: ec2.Vpc
  dbSG:ec2.SecurityGroup
}

export class Rds extends Construct{
  readonly rdsCluster: rds.DatabaseCluster

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

    const {vpc, dbSG} = props
    const instanceType = ec2.InstanceType.of(ec2.InstanceClass.BURSTABLE4_GRAVITON, ec2.InstanceSize.MEDIUM)

    // RDSのパスワードを自動生成してSecrets Managerに格納
    const rdsCredentials = rds.Credentials.fromGeneratedSecret('db_user',{
      secretName: 'langflow-DbSecret',
    })
    
    // DB クラスターのパラメータグループ作成
    const clusterParameterGroup = new rds.ParameterGroup(
      scope,
      "ClusterParameterGroup",
      {
        engine: rds.DatabaseClusterEngine.auroraMysql({
          version: rds.AuroraMysqlEngineVersion.of(
            "8.0.mysql_aurora.3.05.2",
            "8.0"
          ),
        }),
        description: "for-langflow",
      }
    );
    clusterParameterGroup.bindToCluster({})

    // DB インスタンスのパラメタグループ作成
    const instanceParameterGroup = new rds.ParameterGroup(
      scope,
      "InstanceParameterGroup",
      {
        engine: rds.DatabaseClusterEngine.auroraMysql({
          version: rds.AuroraMysqlEngineVersion.of("8.0.mysql_aurora.3.05.2", '8.0'),
        }),
        description: "for-langflow",
      }
    );
    instanceParameterGroup.bindToInstance({})

    this.rdsCluster = new rds.DatabaseCluster(scope, "LangflowDbCluster", {
      engine: rds.DatabaseClusterEngine.auroraMysql({
        version: rds.AuroraMysqlEngineVersion.of(
          "8.0.mysql_aurora.3.05.2",
          "8.0"
        ),
      }),
      storageEncrypted: true,
      credentials: rdsCredentials,
      instanceIdentifierBase: "langflow-instance",
      vpc: vpc,
      vpcSubnets: vpc.selectSubnets({
        subnetGroupName: "langflow-Isolated",
      }),
      securityGroups: [dbSG],
      writer: rds.ClusterInstance.provisioned("WriterInstance", {
        instanceType: instanceType,
        enablePerformanceInsights: true,
        parameterGroup: instanceParameterGroup,
      }),
      // 2台目以降はreaders:で設定
      parameterGroup: clusterParameterGroup,
      defaultDatabaseName: "langflow",
    });
  }
}