AWSTemplateFormatVersion: "2010-09-09"
Transform: AWS::Serverless-2016-10-31
Description: >
  Error Handling in Lambda Function
Parameters:
  CleanInputFunctionName:
    Description: The name of the Clean Input Lambda Function
    Type: String
    Default: CleanInput
  MultiplyFunctionName:
    Description: The name of the Multiply Lambda Function
    Type: String
    Default: Multiply
  AddFunctionName:
    Description: The name of the Add Lambda Function
    Type: String
    Default: Add
  SubtractFunctionName:
    Description: The name of the Subtract Lambda Function
    Type: String
    Default: Subtract
  DivideFunctionName:
    Description: The name of the Divide Lambda Function
    Type: String
    Default: Divide
  NotificationEmail:
    Description: Notification Email
    Type: String
    Default: 'test@gmail.com'

Resources:
  LambdaStateMachine:
    Type: AWS::Serverless::StateMachine # More info about State Machine Resource: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-statemachine.html
    Properties:
      DefinitionUri: statemachine/Lambda_State_Machine_EL.asl.json
      Role: !GetAtt StateMachineRole.Arn
      DefinitionSubstitutions:
        AddFunctionArn: !Ref AddFunction
        CleanFunctionArn: !Ref CleanInputFunction
        DivideFunctionArn: !Ref DivideFunction
        MultiplyFunctionArn: !Ref MultiplyFunction
        SubtractFunctionArn: !Ref SubtractFunction
        TopicArn: !Ref SNSNotificationTopic

  StateMachineRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub statemachine-role-${AWS::StackName}
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: Allow
            Principal:
              Service: states.amazonaws.com
            Action: sts:AssumeRole
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
  InvokeFunctionPolicy:
    Type: AWS::IAM::Policy
    Properties:
      PolicyName: !Sub statemachine-invoke-function-policy-${AWS::StackName}
      Roles:
        - !Ref StateMachineRole
      PolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Action:
              - lambda:InvokeFunction
            Resource: '*'
          - Effect: Allow
            Action:
              - SNS:Publish
            Resource: !Ref SNSNotificationTopic
  SNSNotificationTopic:
    Type: AWS::SNS::Topic
  SNSEmailSubscriber:
    Type: AWS::SNS::Subscription
    Properties:
      Protocol: email
      Endpoint: !Ref NotificationEmail
      TopicArn: !Ref SNSNotificationTopic
  SNSNotificationTopicPolicy:
    Type: AWS::SNS::TopicPolicy
    Properties:
      Topics:
        - !Ref "SNSNotificationTopic"
      PolicyDocument:
        Version: "2008-10-17"
        Id: __default_policy_ID
        Statement:
          - Sid: __default_statement_ID
            Effect: Allow
            Principal:
              AWS: "*"
            Action:
              - SNS:GetTopicAttributes
              - SNS:SetTopicAttributes
              - SNS:AddPermission
              - SNS:RemovePermission
              - SNS:DeleteTopic
              - SNS:Subscribe
              - SNS:ListSubscriptionsByTopic
              - SNS:Publish
              - SNS:Receive
            Resource:
              - !Ref "SNSNotificationTopic"
            Condition:
              StringEquals:
                AWS:SourceOwner:
                  - !Ref "AWS::AccountId"
          - Sid: TrustCWEToPublishEventsToMyTopic
            Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
            Action: sns:Publish
            Resource:
              - !Ref "SNSNotificationTopic"
  AddFunction:
    Type: AWS::Serverless::Function # More info about Function Resource: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-function.html
    Properties:
      Handler: add.lambda_handler
      Runtime: python3.8
      CodeUri: lambdas/add
      FunctionName: !Ref AddFunctionName
      AutoPublishAlias: live
      MemorySize: 128
      Timeout: 30

  CleanInputFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: cleaninput.lambda_handler
      Runtime: python3.8
      CodeUri: lambdas/cleaninput
      FunctionName: !Ref CleanInputFunctionName
      AutoPublishAlias: live
      MemorySize: 128
      Timeout: 30

  DivideFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: divide.lambda_handler
      Runtime: python3.8
      CodeUri: lambdas/divide
      FunctionName: !Ref DivideFunctionName
      AutoPublishAlias: live
      MemorySize: 128
      Timeout: 30

  MultiplyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: multiply.lambda_handler
      Runtime: python3.8
      CodeUri: lambdas/multiply
      FunctionName: !Ref MultiplyFunctionName
      AutoPublishAlias: live
      MemorySize: 128
      Timeout: 30

  SubtractFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: subtract.lambda_handler
      Runtime: python3.8
      CodeUri: lambdas/subtract
      FunctionName: !Ref SubtractFunctionName
      AutoPublishAlias: live
      MemorySize: 128
      Timeout: 30