########################################################################
# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0
########################################################################
AWSTemplateFormatVersion: 2010-09-09
Description:
  This template enables AWS Config in the Control Tower Management account. - 'config_management_account' solution in the repo,
  https://github.com/aws-samples/aws-security-reference-architecture-examples (sra-1ssgnse2s)
Metadata:
  SRA:
    Version: 1.0
    Order: 3
  AWS::CloudFormation::Interface:
    ParameterGroups:
      - Label:
          default: General Properties
        Parameters:
          - pManagedResourcePrefix
          - pAuditAccountId
          - pLogArchiveAccountId
          - pOrganizationId
          - pHomeRegion
      - Label:
          default: Config Recorder Properties
        Parameters:
          - pAllSupported
          - pIncludeGlobalResourceTypes
          - pResourceTypes
      - Label:
          default: Config Delivery Channel Properties
        Parameters:
          - pFrequency
          - pAllConfigTopicName
          - pKmsKeyArn
    ParameterLabels:
      pAllConfigTopicName:
        default: All Config SNS Topic Name
      pAllSupported:
        default: All Supported
      pAuditAccountId:
        default: Audit Account ID
      pFrequency:
        default: Frequency
      pHomeRegion:
        default: Control Tower Home Region
      pIncludeGlobalResourceTypes:
        default: Include Global Resource Types
      pKmsKeyArn:
        default: (Optional) KMS Key ARN
      pLogArchiveAccountId:
        default: Log Archive Account ID
      pManagedResourcePrefix:
        default: Managed Resource Prefix
      pOrganizationId:
        default: Organization ID
      pResourceTypes:
        default: (Optional) Resource Types

Parameters:
  pAllConfigTopicName:
    AllowedValues: [aws-controltower-AllConfigNotifications]
    Default: aws-controltower-AllConfigNotifications
    Description: All Configuration Notification SNS Topic in Audit Account that AWS Config delivers notifications to.
    Type: String
  pAllSupported:
    AllowedValues: ['true', 'false']
    Default: 'true'
    Description: Indicates whether to record all supported resource types. If set to 'false', then the 'Resource Types' parameter must have a value.
    Type: String
  pAuditAccountId:
    AllowedPattern: '^\d{12}$'
    ConstraintDescription: Must be 12 digits.
    Description: AWS Account ID of the Control Tower Audit account.
    Type: String
  pFrequency:
    AllowedValues: [1hour, 3hours, 6hours, 12hours, 24hours]
    Default: 1hour
    Description: The frequency with which AWS Config delivers configuration snapshots.
    Type: String
  pHomeRegion:
    AllowedPattern: '^[a-z0-9-]{1,64}$'
    ConstraintDescription: AWS Region Example - 'us-east-1'
    Description: Name of the Control Tower home region
    Type: String
  pIncludeGlobalResourceTypes:
    AllowedValues: ['true', 'false']
    Default: 'true'
    Description: Indicates whether AWS Config records all supported global resource types.
    Type: String
  pKmsKeyArn:
    AllowedPattern: '^$|^arn:(aws[a-zA-Z-]*)?:kms:[a-z0-9-]+:\d{12}:key\/[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$'
    ConstraintDescription: Key ARN example - arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
    Description:
      (Optional) KMS key ARN to use for encrypting the AWS Config configuration snapshots and history files when storing in the S3 bucket in the Log
      Archive account. If empty, snapshots and history files will be encrypted based on the Default Encryption setting of the S3 bucket.
    Type: String
  pLogArchiveAccountId:
    AllowedPattern: '^\d{12}$'
    ConstraintDescription: Must be 12 digits.
    Description: AWS Account ID of the Control Tower Log Archive account.
    Type: String
  pManagedResourcePrefix:
    AllowedValues: [aws-controltower]
    Default: aws-controltower
    Description: Prefix for the managed resources.
    Type: String
  pOrganizationId:
    AllowedPattern: '^o-[a-z0-9]{10,32}$'
    ConstraintDescription: Must start with 'o-' followed by from 10 to 32 lowercase letters or digits. (e.g. o-abc1234567)
    Description: AWS Organizations ID
    Type: String
  pResourceTypes:
    AllowedPattern: '^$|^([a-zA-Z]+::[a-zA-Z]+::[a-zA-Z]+)$|^(([a-zA-Z]+::[a-zA-Z]+::[a-zA-Z]+(,|, ))*[a-zA-Z]+::[a-zA-Z]+::[a-zA-Z]+)$'
    Description:
      (Optional) A list of valid AWS resource types to include in this recording group. Eg. AWS::CloudTrail::Trail. If 'All Supported' parameter is
      set to 'false', then this parameter becomes required.
    Type: String

Rules:
  ResourceTypesValidation:
    RuleCondition: !Equals [!Ref pResourceTypes, '']
    Assertions:
      - AssertDescription: "'Resource Types' parameter is required if the 'All Supported' parameter is set to 'true'."
        Assert: !Equals [!Ref pAllSupported, 'true']

Conditions:
  cIsAllSupported: !Equals [!Ref pAllSupported, 'true']
  cIsUsingKmsKey: !Not [!Equals [!Ref pKmsKeyArn, '']]
  cIsHomeRegion: !Equals [!Ref 'AWS::Region', !Ref pHomeRegion]

Mappings:
  mSettings:
    FrequencyMap:
      1hour: One_Hour
      3hours: Three_Hours
      6hours: Six_Hours
      12hours: Twelve_Hours
      24hours: TwentyFour_Hours

Resources:
  rAuthorizer:
    Type: AWS::Config::AggregationAuthorization
    Properties:
      AuthorizedAccountId: !Ref pAuditAccountId
      AuthorizedAwsRegion: !Ref pHomeRegion

  rConfigDeliveryChannel:
    Type: AWS::Config::DeliveryChannel
    Properties:
      Name: !Sub ${pManagedResourcePrefix}-BaselineConfigDeliveryChannel
      ConfigSnapshotDeliveryProperties:
        DeliveryFrequency: !FindInMap
          - mSettings
          - FrequencyMap
          - !Ref pFrequency
      S3BucketName: !Sub aws-controltower-logs-${pLogArchiveAccountId}-${pHomeRegion}
      S3KeyPrefix: !Ref pOrganizationId
      S3KmsKeyArn: !If
        - cIsUsingKmsKey
        - !Ref pKmsKeyArn
        - !Ref AWS::NoValue
      SnsTopicARN: !Sub arn:${AWS::Partition}:sns:${AWS::Region}:${pAuditAccountId}:${pAllConfigTopicName}

  rConfigRecorder:
    Type: AWS::Config::ConfigurationRecorder
    Properties:
      Name: !Sub ${pManagedResourcePrefix}-BaselineConfigRecorder
      RoleARN: !Sub arn:${AWS::Partition}:iam::${AWS::AccountId}:role/${pManagedResourcePrefix}-ConfigRecorderRole
      RecordingGroup:
        AllSupported: !Ref pAllSupported
        IncludeGlobalResourceTypes: !If
          - cIsHomeRegion
          - !Ref pIncludeGlobalResourceTypes
          - !Ref AWS::NoValue
        ResourceTypes: !If
          - cIsAllSupported
          - !Ref AWS::NoValue
          - !Ref pResourceTypes

Outputs:
  oConfigDeliveryChannel:
    Description: AWS Config Delivery Channel
    Value: !Ref rConfigDeliveryChannel
  oConfigRecorder:
    Description: AWS Config Recorder
    Value: !Ref rConfigRecorder