import * as cdk from "aws-cdk-lib";
import * as s3 from "aws-cdk-lib/aws-s3";
import * as iam from "aws-cdk-lib/aws-iam";
import * as guardduty from "aws-cdk-lib/aws-guardduty";
import * as securityhub from "aws-cdk-lib/aws-securityhub";
import * as accessanalyzer from "aws-cdk-lib/aws-accessanalyzer";
import * as cr from "aws-cdk-lib/custom-resources";
import { Construct } from "constructs";

/**
 * Account-level detective controls for the isolated external-dev account.
 *
 * Adapted from seahaven-account-baseline/lib/detective-controls.ts. Provides:
 *   AWS Config recorder + delivery channel (CIS 3.3/3.5)
 *   GuardDuty detector
 *   Security Hub with AWS FSBP + CIS v3.0 standards
 *   IAM Access Analyzer (account-scoped external-access analyzer)
 *
 * Inspector2 has no CloudFormation enable resource and is a documented
 * post-deploy CLI step (see README), matching the prod baseline.
 *
 * Scope is us-east-1 only (the account is region-locked by SCP). No local
 * CloudTrail and no CIS Section-4 metric-filter alarms: the management-account
 * organization trail (seahaven-org-trail) already captures this account's
 * events centrally, and the Security Hub CIS standard below evaluates the CIS
 * controls against AWS Config without needing a local trail log group.
 */
export class DetectiveControls extends Construct {
  constructor(scope: Construct, id: string) {
    super(scope, id);

    const stack = cdk.Stack.of(this);

    // ──────────────────────────────────────────────────────────────────────
    // AWS Config
    // ──────────────────────────────────────────────────────────────────────

    // Delivery bucket for Config snapshots/history. Private, TLS-only,
    // versioned, SSE-S3 (Config writes here; SSE-S3 avoids a second KMS-grant
    // failure mode and is sufficient — CIS does not require a CMK here).
    const configBucket = new s3.Bucket(this, "ConfigBucket", {
      bucketName: `seahaven-extdev-config-${stack.account}`,
      encryption: s3.BucketEncryption.S3_MANAGED,
      blockPublicAccess: s3.BlockPublicAccess.BLOCK_ALL,
      enforceSSL: true,
      versioned: true,
      lifecycleRules: [
        {
          id: "expire-old-config",
          expiration: cdk.Duration.days(365),
          abortIncompleteMultipartUploadAfter: cdk.Duration.days(7),
        },
      ],
      removalPolicy: cdk.RemovalPolicy.RETAIN,
    });

    // Bucket policy that lets the Config service principal verify ownership
    // and deliver objects (scoped to this account, owner-full-control ACL).
    configBucket.addToResourcePolicy(
      new iam.PolicyStatement({
        sid: "AWSConfigBucketPermissionsCheck",
        effect: iam.Effect.ALLOW,
        principals: [new iam.ServicePrincipal("config.amazonaws.com")],
        actions: ["s3:GetBucketAcl", "s3:ListBucket"],
        resources: [configBucket.bucketArn],
        conditions: {
          StringEquals: { "aws:SourceAccount": stack.account },
        },
      })
    );
    configBucket.addToResourcePolicy(
      new iam.PolicyStatement({
        sid: "AWSConfigBucketDelivery",
        effect: iam.Effect.ALLOW,
        principals: [new iam.ServicePrincipal("config.amazonaws.com")],
        actions: ["s3:PutObject"],
        resources: [
          configBucket.arnForObjects(`AWSLogs/${stack.account}/Config/*`),
        ],
        conditions: {
          StringEquals: {
            "s3:x-amz-acl": "bucket-owner-full-control",
            "aws:SourceAccount": stack.account,
          },
        },
      })
    );

    // Recorder role — assumed by Config. AWS_ConfigRole grants the read/describe
    // permissions Config needs to record every resource type; the inline policy
    // grants delivery to the bucket above. (IAM change — cross-review per
    // CLAUDE.md; pattern replicated verbatim from the cross-reviewed prod
    // baseline.)
    const recorderRole = new iam.Role(this, "ConfigRecorderRole", {
      roleName: "seahaven-extdev-config-recorder-role",
      assumedBy: new iam.ServicePrincipal("config.amazonaws.com"),
      managedPolicies: [
        iam.ManagedPolicy.fromAwsManagedPolicyName("service-role/AWS_ConfigRole"),
      ],
    });
    recorderRole.addToPolicy(
      new iam.PolicyStatement({
        sid: "ConfigDeliveryToBucket",
        effect: iam.Effect.ALLOW,
        actions: ["s3:PutObject"],
        resources: [
          configBucket.arnForObjects(`AWSLogs/${stack.account}/Config/*`),
        ],
        conditions: {
          StringEquals: { "s3:x-amz-acl": "bucket-owner-full-control" },
        },
      })
    );
    recorderRole.addToPolicy(
      new iam.PolicyStatement({
        sid: "ConfigBucketAcl",
        effect: iam.Effect.ALLOW,
        actions: ["s3:GetBucketAcl"],
        resources: [configBucket.bucketArn],
      })
    );

    // ── AWS Config recorder + delivery channel ─────────────────────────────
    //
    // The L1 AWS::Config::ConfigurationRecorder is a stabilizing resource that
    // deadlocks the stack: it never reaches CREATE_COMPLETE until recording is
    // active, which requires a delivery channel, which can't be created until
    // the recorder is complete. Fix (from the prod baseline): an
    // AwsCustomResource calls the Config SDK directly — Put* is an upsert.
    // Sequence: PutConfigurationRecorder -> PutDeliveryChannel ->
    // StartConfigurationRecorder. onDelete stops (does not delete) the
    // per-account-singleton recorder.
    const configCustomResourceRole = new iam.Role(
      this,
      "ConfigCustomResourceRole",
      {
        roleName: "seahaven-extdev-config-custom-resource-role",
        assumedBy: new iam.ServicePrincipal("lambda.amazonaws.com"),
        managedPolicies: [
          iam.ManagedPolicy.fromAwsManagedPolicyName(
            "service-role/AWSLambdaBasicExecutionRole"
          ),
        ],
        inlinePolicies: {
          ConfigRecorderAdoption: new iam.PolicyDocument({
            statements: [
              new iam.PolicyStatement({
                sid: "ConfigRecorderManage",
                effect: iam.Effect.ALLOW,
                actions: [
                  "config:PutConfigurationRecorder",
                  "config:PutDeliveryChannel",
                  "config:StartConfigurationRecorder",
                  "config:StopConfigurationRecorder",
                ],
                // Config recorder/channel are account-level singletons with no
                // ARN in resource policies — the API only accepts "*" here.
                resources: ["*"],
              }),
              new iam.PolicyStatement({
                sid: "PassRecorderRole",
                effect: iam.Effect.ALLOW,
                actions: ["iam:PassRole"],
                resources: [recorderRole.roleArn],
                conditions: {
                  StringEquals: {
                    "iam:PassedToService": "config.amazonaws.com",
                  },
                },
              }),
            ],
          }),
        },
      }
    );

    const putRecorderCall: cr.AwsSdkCall = {
      service: "ConfigService",
      action: "putConfigurationRecorder",
      parameters: {
        ConfigurationRecorder: {
          name: "seahaven-extdev-config-recorder",
          roleARN: recorderRole.roleArn,
          recordingGroup: {
            allSupported: true,
            includeGlobalResourceTypes: true,
          },
        },
      },
      physicalResourceId: cr.PhysicalResourceId.of(
        "seahaven-extdev-config-recorder"
      ),
    };

    const putChannelCall: cr.AwsSdkCall = {
      service: "ConfigService",
      action: "putDeliveryChannel",
      parameters: {
        DeliveryChannel: {
          name: "seahaven-extdev-config-delivery",
          s3BucketName: configBucket.bucketName,
          configSnapshotDeliveryProperties: {
            deliveryFrequency: "TwentyFour_Hours",
          },
        },
      },
      physicalResourceId: cr.PhysicalResourceId.of(
        "seahaven-extdev-config-delivery"
      ),
    };

    const startRecorderCall: cr.AwsSdkCall = {
      service: "ConfigService",
      action: "startConfigurationRecorder",
      parameters: {
        ConfigurationRecorderName: "seahaven-extdev-config-recorder",
      },
      physicalResourceId: cr.PhysicalResourceId.of(
        "seahaven-extdev-config-recorder-start"
      ),
    };

    const putRecorder = new cr.AwsCustomResource(this, "ConfigPutRecorder", {
      onCreate: putRecorderCall,
      onUpdate: putRecorderCall,
      role: configCustomResourceRole,
      installLatestAwsSdk: false,
    });

    const putChannel = new cr.AwsCustomResource(this, "ConfigPutChannel", {
      onCreate: putChannelCall,
      onUpdate: putChannelCall,
      role: configCustomResourceRole,
      installLatestAwsSdk: false,
    });
    putChannel.node.addDependency(putRecorder);

    const startRecorder = new cr.AwsCustomResource(this, "ConfigStartRecorder", {
      onCreate: startRecorderCall,
      onUpdate: startRecorderCall,
      onDelete: {
        service: "ConfigService",
        action: "stopConfigurationRecorder",
        parameters: {
          ConfigurationRecorderName: "seahaven-extdev-config-recorder",
        },
        physicalResourceId: cr.PhysicalResourceId.of(
          "seahaven-extdev-config-recorder-stop"
        ),
      },
      role: configCustomResourceRole,
      installLatestAwsSdk: false,
    });
    startRecorder.node.addDependency(putChannel);

    new cdk.CfnOutput(this, "ConfigRecorderRoleArn", {
      value: recorderRole.roleArn,
    });

    // ──────────────────────────────────────────────────────────────────────
    // GuardDuty
    // ──────────────────────────────────────────────────────────────────────
    new guardduty.CfnDetector(this, "GuardDutyDetector", {
      enable: true,
      findingPublishingFrequency: "FIFTEEN_MINUTES",
    });

    // ──────────────────────────────────────────────────────────────────────
    // Security Hub (FSBP + CIS v3.0) — the CIS coverage substitute for the
    // dropped Section-4 metric alarms; evaluates against Config, not a trail.
    // ──────────────────────────────────────────────────────────────────────
    const hub = new securityhub.CfnHub(this, "SecurityHub", {
      enableDefaultStandards: false,
      controlFindingGenerator: "SECURITY_CONTROL",
      autoEnableControls: true,
    });

    const fsbpArn = cdk.Arn.format(
      {
        service: "securityhub",
        region: stack.region,
        account: "",
        resource: "standards",
        resourceName: "aws-foundational-security-best-practices/v/1.0.0",
      },
      stack
    );
    const cisArn = cdk.Arn.format(
      {
        service: "securityhub",
        region: stack.region,
        account: "",
        resource: "standards",
        resourceName: "cis-aws-foundations-benchmark/v/3.0.0",
      },
      stack
    );

    const fsbp = new securityhub.CfnStandard(this, "StandardFSBP", {
      standardsArn: fsbpArn,
    });
    fsbp.node.addDependency(hub);

    const cis = new securityhub.CfnStandard(this, "StandardCIS", {
      standardsArn: cisArn,
    });
    cis.node.addDependency(hub);

    // ──────────────────────────────────────────────────────────────────────
    // IAM Access Analyzer (free, account-scoped external-access)
    // ──────────────────────────────────────────────────────────────────────
    new accessanalyzer.CfnAnalyzer(this, "AccountAnalyzer", {
      analyzerName: "seahaven-extdev-account-analyzer",
      type: "ACCOUNT",
    });

    // Inspector2 (EC2 + ECR + Lambda) has NO CloudFormation resource for
    // *enabling* the service — it is a post-deploy CLI step, documented in the
    // README runbook (same as the prod baseline):
    //   aws inspector2 enable --resource-types EC2 ECR LAMBDA \
    //     --account-ids <account>

    new cdk.CfnOutput(this, "ConfigBucketName", {
      value: configBucket.bucketName,
    });
  }
}