# SPDX-FileCopyrightText: 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0 


# This is the SAM template that represents the architecture of your serverless application
# https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-template-basics.html

# The AWSTemplateFormatVersion identifies the capabilities of the template
# https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/format-version-structure.html
AWSTemplateFormatVersion: 2010-09-09
Description: >-
  serverlessLandBlogUpdator

# Transform section specifies one or more macros that AWS CloudFormation uses to process your template
# https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/transform-section-structure.html
Transform:
- AWS::Serverless-2016-10-31

Parameters:
  RSSFeed:
    Type: String
    Description: 'RSS feed to scan'
    Default: 'https://aws.amazon.com/blogs/compute/feed'

  GitHubRepo:
    Type: String
    Description: Full URL of the GitHub Repository that holds your application eg. https://github.com/username/repo-name\
    Default: ''

  JSONFile:
    Type: String
    Description: JSON file that holds blog content eg. content.json
    Default: 'frontend/content.json'

# Resources declares the AWS resources that you want to include in the stack
# https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/resources-section-structure.html
Resources:

  StateMachineRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
        - Effect: Allow
          Principal:
            Service: !Sub states.${AWS::Region}.amazonaws.com
          Action: sts:AssumeRole
      Policies:
      - PolicyName: lambda
        PolicyDocument:
          Statement:
          - Effect: Allow
            Action: lambda:InvokeFunction
            Resource:
              - !GetAtt GetBlogPost.Arn
              - !GetAtt GetUrls.Arn
              - !GetAtt CompareAgainstRepo.Arn
              - !GetAtt WriteToGitHub.Arn
              - !GetAtt AddToList.Arn
              - !GetAtt GetRepoContents.Arn
  SSMAccessRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          -
            Effect: Allow
            Principal:
              Service:
                - 'lambda.amazonaws.com'
            Action:
              - 'sts:AssumeRole'
      ManagedPolicyArns:
        - 'arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole'
      Policies:
        -
          PolicyName: 'ParameterStoreAccess'
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              -
                Effect: Allow
                Action:
                  - 'ssm:GetParameter*'
                Resource: !Sub 'arn:aws:ssm:${AWS::Region}:${AWS::AccountId}:parameter/GitHubAPIKey'

  MyStateMachine:
    Type: AWS::Serverless::StateMachine
    Properties:
      DefinitionUri: statemachine/my_state_machine.asl.json
      DefinitionSubstitutions:
        GetBlogPostArn: !GetAtt GetBlogPost.Arn
        GetUrlsArn: !GetAtt GetUrls.Arn
        WriteToGitHubArn: !GetAtt WriteToGitHub.Arn
        CompareAgainstRepoArn: !GetAtt CompareAgainstRepo.Arn
        GetRepoContentsArn: !GetAtt GetRepoContents.Arn
        AddToListArn: !GetAtt AddToList.Arn
      Role: !GetAtt StateMachineRole.Arn

  # Each Lambda function is defined by properties:
  # https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
  
  #MyStateMachine:
  #  Properties:
  #  Type: AWS::Serverless::StateMachine
  #    DefinitionUri: statemachine/my_state_machine.asl.json

  # This is a Lambda function config associated with the source code: hello-from-lambda.js
  GetBlogPost:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: src/scrape-blog/
      Handler: GetBlogPost.handler
      Runtime: nodejs12.x
      MemorySize: 128
      Timeout: 100
      Description: A Lambda function that returns a static string.
      Policies:
        # Give Lambda basic execution Permission to the helloFromLambda
        - AWSLambdaBasicExecutionRole
  GetUrls:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: src/urls/
      Handler: GetUrls.handler
      Runtime: nodejs12.x
      MemorySize: 128
      Timeout: 100
      Description: A Lambda function that returns a static string.
      Policies:
        # Give Lambda basic execution Permission to the helloFromLambda
        - AWSLambdaBasicExecutionRole

  CompareAgainstRepo:
    Type: AWS::Serverless::Function
    Properties:
      Environment:
        Variables:
          GitHubRepo: !Ref GitHubRepo
          JSONFile: !Ref JSONFile
      CodeUri: src/compare-against-repo/
      Handler: CompareAgainstRepo.handler
      Runtime: nodejs12.x
      MemorySize: 128
      Timeout: 100
      Description: A Lambda function that Gets File Contents from Github and checks if payload item exists already.
      Role: !GetAtt SSMAccessRole.Arn

  GetRepoContents:
    Type: AWS::Serverless::Function
    Properties:
      Environment:
        Variables:
          GitHubRepo: !Ref GitHubRepo
          JSONFile: !Ref JSONFile
      CodeUri: src/get-repo-contents/
      Handler: GetRepoContents.handler
      Runtime: nodejs12.x
      MemorySize: 128
      Timeout: 100
      Description: A Lambda function that Gets File Contents from Github and checks if payload item exists already.
      Role: !GetAtt SSMAccessRole.Arn
      
  AddToList:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: src/add-to-list/
      Handler: addToList.handler
      Runtime: nodejs12.x
      MemorySize: 128
      Timeout: 100
      Description: A Lambda function that returns a static string.
      Policies:
        # Give Lambda basic execution Permission to the helloFromLambda
        - AWSLambdaBasicExecutionRole
  
  
  WriteToGitHub:
    Type: AWS::Serverless::Function
    Properties:
      Environment:
        Variables:
          GitHubRepo: !Ref GitHubRepo
          JSONFile: !Ref JSONFile
      CodeUri: src/update-github/
      Handler: WriteToGitHub.handler
      Runtime: nodejs12.x
      MemorySize: 128
      Timeout: 100
      Description: A Lambda function that returns a static string.
      Role: !GetAtt SSMAccessRole.Arn

  ScheduledEventIAMRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          -
            Effect: "Allow"
            Principal:
              Service:
                  - Fn::Sub: "events.amazonaws.com"
            Action:
              - "sts:AssumeRole"
      Policies:
        -
          PolicyName: StateMachineExecutionPolicy
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              -
                Effect: "Allow"
                Action: "states:StartExecution"
                Resource:
                  - !Ref MyStateMachine

  ScheduledEventRule:
    Type: "AWS::Events::Rule"
    Properties:
      Description: "Scheduled event to trigger Step Functions state machine"
      ScheduleExpression: rate(2 hours)
      State: "ENABLED"
      Targets:
        -
          Arn: !Ref MyStateMachine
          Id: !GetAtt MyStateMachine.Name
          RoleArn: !GetAtt ScheduledEventIAMRole.Arn
          Input: !Sub
            - >
              {
                "feedUrl" : "${RssFeedUrl}"
              }
            - RssFeedUrl: !Ref RSSFeed