AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  Orange service app for for single bus, multi-account-pattern

# More info about Globals: https://github.com/awslabs/serverless-application-model/blob/master/docs/globals.rst
Globals:
  Function:
    Handler: app.lambda_handler
    Runtime: python3.9
    Timeout: 3

Parameters:
  EventBusName:
    Description: Name of the orange service app event bus
    Type: String
    Default: orange-service-event-bus

  DevOpsEventBusArn:
    Description: The ARN of the devops event bus # e.g. arn:aws:events:us-east-1:[DEVOPS-ACCOUNT]:event-bus/devops-event-bus
    Type: String
    
Resources:

  # Event bus for orange service. In single bus topology 
  # this is the target for the devops event bus rule 
  OrangeServiceEventBus: 
    Type: AWS::Events::EventBus
    Properties: 
        Name: !Ref EventBusName

  OrangeServicePublisherE3:
    Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      CodeUri: orange_p_e3/
      Policies:
        - Version: '2012-10-17' 
          Statement:
            - Effect: Allow
              Action:
                - events:PutEvents
              Resource: "*" 
      Environment:
        Variables:
          DEVOPS_EVENT_BUS_ARN: !Ref DevOpsEventBusArn

  OrangeServiceSubscriberE2:
    Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      CodeUri: orange_s_e2/
      Events:
        OrangeE2Rule:
          Type: EventBridgeRule
          Properties:
            EventBusName: !Ref OrangeServiceEventBus
            Pattern:
              source:
                - com.exampleCorp.PurpleService
              detail-type:
                - Event2
  # Rule that is placed on the DevOps event bus for Event 2
  OrangeServiceEvent2SubscriptionRule:
    Type: AWS::Events::Rule
    Properties:
      Name: OrangeE2Subscription
      Description: Cross account rule created by Orange service for event 2
      EventBusName: !Ref DevOpsEventBusArn # ARN of the devops event bus
      EventPattern:
        source:
          - com.exampleCorp.PurpleService
        detail-type:
          - Event2
      State: ENABLED
      Targets: 
        - Id: SendEvent2ToOrangeServiceEventBus
          Arn: !GetAtt OrangeServiceEventBus.Arn
          RoleArn: !GetAtt DevOpsEventBusToOrangeServiceEventBusRole.Arn
          DeadLetterConfig:
            Arn: !GetAtt OrangeServiceEventBusDlq.Arn

  # This IAM role allows EventBridge to assume the permissions necessary to send events 
  # from the DevOps event bus to the Orange service event bus. No resource policy is required
  # on the Orange service event bus.
  DevOpsEventBusToOrangeServiceEventBusRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
              - events.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: /
      Policies:   
        - PolicyName: PutEventsOnOrangeServiceEventBus
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action: 'events:PutEvents'
                Resource: !GetAtt OrangeServiceEventBus.Arn

  # Orange service event bus targe DLQ 
  OrangeServiceEventBusDlq:
    Type: AWS::SQS::Queue

  # SQS resource policy required to allow target on devops bus to send failed messages to target DLQ
  OrangeServiceEventBusDlqPolicy: 
    Type: AWS::SQS::QueuePolicy
    Properties: 
      Queues: 
        - !Ref OrangeServiceEventBusDlq
      PolicyDocument: 
        Statement: 
          - Action: 
              - "SQS:SendMessage" 
            Effect: "Allow"
            Resource: !GetAtt OrangeServiceEventBusDlq.Arn
            Principal:  
              Service: "events.amazonaws.com"
            Condition:
              ArnEquals:
                "aws:SourceArn": !GetAtt OrangeServiceEvent2SubscriptionRule.Arn
         
Outputs:
  OrangeServicePublisherE3:
    Description: Lambda function name for Orange service publishing event 3
    Value: !Ref OrangeServicePublisherE3
  OrangeServiceSubscriberE2:
    Description: Lambda function name for orange service subscriber to event 2
    Value: !Ref OrangeServiceSubscriberE2
  OrangeServiceEventBusDlqUrl:
    Description: URL of the SQS Queue for rules DeadLetterConfig
    Value: !Ref OrangeServiceEventBusDlq
  OrangeServiceEventBusDlqArn:
    Description: ARN of the SQS Queue for rules DeadLetterConfig
    Value: !GetAtt OrangeServiceEventBusDlq.Arn