AWSTemplateFormatVersion: '2010-09-09'
Description: AWS Step Functions sample project demonstrating the Request Response pattern

Resources:
  SNSTopic:
    Type: 'AWS::SNS::Topic'
    Properties:
      DisplayName: 'RequestResponseTopic'

  StatesExecutionRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: 'Allow'
            Principal:
              Service: states.amazonaws.com
            Action: 'sts:AssumeRole'
      Path: '/'
      Policies:
        - PolicyName: StatesExecutionPolicy
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action:
                  - 'sns:Publish'
                Resource: !Ref SNSTopic

  RequestResponseStateMachine:
    Type: 'AWS::StepFunctions::StateMachine'
    Properties:
      DefinitionString: !Sub
        - |-
          {
            "Comment": "An example of the Amazon States Language for scheduling a task.",
            "StartAt": "Wait for Timestamp",
            "States": {
              "Wait for Timestamp": {
                "Type": "Wait",
                "SecondsPath": "$.timer_seconds",
                "Next": "Send SNS Message"
              },
              "Send SNS Message": {
                "Type": "Task",
                "Resource": "arn:aws:states:::sns:publish",
                "Parameters":{  
                  "TopicArn": "${topicArn}",
                  "Message.$":"$.message"
                },
                "End": true
              }
            }
          }
        - { topicArn: !Ref SNSTopic }
      RoleArn: !GetAtt [StatesExecutionRole, Arn]

Outputs:
  StateMachineArn:
    Value:
      Ref: RequestResponseStateMachine
  ExecutionInput:
    Description: Sample input to StartExecution.
    Value: !Sub
      - |-
        {
          "topic": "${topicArn}",
          "message": "Welcome to re:Invent!",
          "timer_seconds": 5
        }
      - { topicArn: !Ref SNSTopic }