AWSTemplateFormatVersion: "2010-09-09"
Transform: AWS::Serverless-2016-10-31
Description: >
  Sample minimalistic binary decoder for AWS IoT Core for LoRaWAN

Parameters:
  TopicError:
    Type: String
    Default: workshop/error
    Description: Name of MQTT topic for to publish IoT Rule action error messages

  TopicDebug:
    Type: String
    Default: workshop/debug
    Description: |
      Prefix of a MQTT topic to publish debugging information

Resources:
  ############################################################################################
  # Payload transformation Lambda function to be called from AWS IoT Core. This function will refer to
  # layer "DecoderLayer" to include the necessary decoding libraries
  ############################################################################################

  TransformLoRaWANBinaryPayloadFunction:
    Type: AWS::Serverless::Function
    Name: !Sub "${AWS::StackName}-BinaryDecoderTutorialFunction"
    Properties:
      CodeUri: src
      Handler: app.lambda_handler
      Runtime: python3.7
      Timeout: 10

  TransformLoRaWANBinaryPayloadFunctionPermission:
    Type: AWS::Lambda::Permission
    Properties:
      FunctionName: !GetAtt TransformLoRaWANBinaryPayloadFunction.Arn
      Action: lambda:InvokeFunction
      Principal: iot.amazonaws.com

  TransformLoRaWANBinaryPayloadRule:
    Type: "AWS::IoT::TopicRule"
    Properties:
      RuleName: !Sub "${AWS::StackName}_TransformLoRaWANBinaryPayloadRule_dragino_lht65"
      TopicRulePayload:
        AwsIotSqlVersion: "2016-03-23"
        RuleDisabled: false

        Sql: !Sub
          - |
            SELECT aws_lambda("${LambdaARN}",
                              {
                                "PayloadData":PayloadData, 
                                "WirelessDeviceId": WirelessDeviceId, 
                                "WirelessMetadata": WirelessMetadata
                              }
                            ) as transformationresult
          - { LambdaARN: !GetAtt TransformLoRaWANBinaryPayloadFunction.Arn }
        Actions:
          - Republish:
              RoleArn: !GetAtt TransformLoRaWANBinaryPayloadRuleRole.Arn
              Topic: !Ref TopicDebug
              Qos: 0

        ErrorAction:
          Republish:
            RoleArn: !GetAtt TransformLoRaWANBinaryPayloadRuleRole.Arn
            Topic: !Ref TopicError
            Qos: 0

  TransformLoRaWANBinaryPayloadRuleRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - iot.amazonaws.com
            Action:
              - "sts:AssumeRole"
      Policies:
        - PolicyName: root
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action: iot:Publish
                Resource:
                  !Join [
                    "",
                    [
                      "arn:aws:iot:",
                      !Ref "AWS::Region",
                      ":",
                      !Ref "AWS::AccountId",
                      ":topic/",
                      !Ref TopicDebug,
                    ],
                  ]
              - Effect: Allow
                Action: iot:Publish
                Resource:
                  !Join [
                    "",
                    [
                      "arn:aws:iot:",
                      !Ref "AWS::Region",
                      ":",
                      !Ref "AWS::AccountId",
                      ":topic/",
                      !Ref TopicError,
                    ],
                  ]

Outputs:
  TransformLoRaWANBinaryPayloadFunctionArn:
    Value: !Ref TransformLoRaWANBinaryPayloadFunction