Description: >
  This template sets up AWS Health Tool to send custom text or SMS notifications via Amazon SNS when an AWS Health event happens by using AWS Lambda and Amazon CloudWatch Events.


Parameters:
  PhoneNumber:
    Type: String
    Default: +1XXX5550100
    Description: The phone number to send notifications to.


Metadata:
  AWS::CloudFormation::Interface:
    ParameterLabels:
      PhoneNumber:
        default: "Phone number"
    ParameterGroups:
      - Label:
          default: AWS Health Tool Configuration
        Parameters:
          - PhoneNumber


Resources:
  LambdaExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          -
            Effect: Allow
            Principal:
              Service:
                - lambda.amazonaws.com
            Action:
              - sts:AssumeRole
      Path: "/"

  LambdaRolePolicies:
    Type: AWS::IAM::Policy
    Properties:
      PolicyName: sms-notifier
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          -
            Effect: Allow
            Action: sns:Publish
            Resource: '*'
          -
            Effect: Allow
            Action:
              - logs:CreateLogGroup
              - logs:CreateLogStream
              - logs:PutLogEvents
            Resource: arn:aws:logs:*:*:*
      Roles:
        -
          Ref: LambdaExecutionRole

  SmsNotifierFunction:
    Type: AWS::Lambda::Function
    Properties:
      Handler: index.handler
      Role: !GetAtt LambdaExecutionRole.Arn
      Environment:
        Variables:
          PHONE_NUMBER: !Ref PhoneNumber
      Code:
        ZipFile: >
          // Sample Lambda Function to send notifications via text when an  AWS Health event happens

          'use strict';

          let AWS = require('aws-sdk');

          let sns = new AWS.SNS();

          //main function which gets AWS Health data from Cloudwatch event

          exports.handler = (event, context, callback) => {
              //get phone number from Env Variable
              let phoneNumber = process.env.PHONE_NUMBER;
              //extract details from Cloudwatch event
              let eventName = event.detail.eventTypeCode
              let healthMessage = `The following AWS Health event type has occured: ${eventName} For more details, please see https://phd.aws.amazon.com/phd/home?region=us-east-1#/dashboard/open-issues`;
              //prepare message for SNS to publish
              let snsPublishParams = {
                  Message: healthMessage,
                  PhoneNumber: phoneNumber,
              };
              sns.publish(snsPublishParams,(err,data) => {
                if (err) {
                  const snsPublishErrorMessage = `Error publishing AWS Health event to SNS`;
                  console.log(snsPublishErrorMessage, err, err.stack); // adding the err.stack
                  callback(snsPublishErrorMessage);
                }

                const snsPublishSuccessMessage = `Successfully got details from AWS Health event, ${eventName} and sent SMS via SNS.`;
                console.log(snsPublishSuccessMessage, data);
                callback(null, snsPublishSuccessMessage); //return success
              });
          };
      Runtime: nodejs12.x

  AwsHealthEventRule:
    Type: AWS::Events::Rule
    Properties:
      Description: AWSHealthEventRule
      EventPattern:
        source:
          - aws.health
      State: ENABLED
      Targets:
        -
          Arn: !GetAtt SmsNotifierFunction.Arn
          Id: SmsNotifierLambdaFunction

  PermissionForEventsToInvokeLambda:
    Type: AWS::Lambda::Permission
    Properties:
      FunctionName: !Ref SmsNotifierFunction
      Action: lambda:InvokeFunction
      Principal: events.amazonaws.com
      SourceArn: !GetAtt AwsHealthEventRule.Arn