AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Sends notifications from S3 to SNS when an object is created

Parameters:
  SourceBucketName:
    Type: String
    
Resources:
  ## S3 bucket
  SourceBucket:
    Type: AWS::S3::Bucket
    DependsOn:
      - SNSTopicPolicy
    Properties:
      BucketName: !Ref SourceBucketName
      NotificationConfiguration:
        TopicConfigurations:
          - Event: s3:ObjectCreated:*
            Topic: !Ref SNSTopic
  
  SNSTopic:
    Type: AWS::SNS::Topic
            
  SNSTopicPolicy:
    Type: AWS::SNS::TopicPolicy
    Properties:
      PolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service: 's3.amazonaws.com'
            Action: sns:Publish
            Resource: !Ref SNSTopic
            Condition:
              ArnEquals:
                aws:SourceArn: !Join ["",['arn:aws:s3:::',!Ref SourceBucketName]]
              StringEquals:
                aws:SourceAccount: !Ref 'AWS::AccountId'
      Topics:
        - !Ref SNSTopic