AWSTemplateFormatVersion: "2010-09-09"
Transform: AWS::Serverless-2016-10-31
Description: >
  Transformation of LoRaWAN binary payloads

Parameters:
  ParamBinaryDecoderName:
    Type: String
    Default: sample_device
    Description: Name of binary decoder as configured in src-iotrule-transformation/app.py

  TopicOutgoingErrors:
    Type: String
    Default: lorawanerror
    Description: Topic for errors

  TopicOutgoingTransformedMessages:
    Type: String
    Default: lorawantransformed
    Description: Prefix for outgoing transformed messages

  EnableNodeJSSupport:
    Description: If set to true, will deploy AWS Lambda NodeJS function and AWS IoT Rule to perform binary decoding using NodeJS
    Type: String
    Default: true
    AllowedValues:
      - true
      - false

  EnablePythonSupport:
    Description: If set to true, will deploy AWS Lambda Python function and respective AWS IoT Rule to perform binary decoding using NodeJS
    Type: String
    Default: true
    AllowedValues:
      - true
      - false

Conditions:
  IsNodeSupportEnabled: !Equals
    - !Ref EnableNodeJSSupport
    - true
  IsPythonSupportEnabled: !Equals
    - !Ref EnablePythonSupport
    - true

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
  ############################################################################################

  TransformLoRaWANBinaryPayloadFunctionPython:
    Type: AWS::Serverless::Function
    Name: !Sub "${AWS::StackName}-TransformLoRaWANBinaryPayloadFunctionPython"
    Properties:
      CodeUri: src-iotrule-transformation
      Handler: app.lambda_handler
      Runtime: python3.7
      Layers:
        - Ref: LoRaWANPayloadDecoderLayer
      Environment:
        Variables:
          RETURN_RAW_DATA: True

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

  TransformLoRaWANBinaryPayloadFunctionNode:
    Type: AWS::Serverless::Function
    Condition: IsNodeSupportEnabled
    Name: !Sub "${AWS::StackName}-TransformLoRaWANBinaryPayloadFunctionNode"
    Properties:
      CodeUri: src-iotrule-transformation-nodejs
      Handler: index.handler
      Runtime: nodejs12.x
      Layers:
        - Ref: LoRaWANPayloadDecoderLayer
      Environment:
        Variables:
          RETURN_RAW_DATA: True

  ############################################################################################
  # LAYERS
  ############################################################################################
  LoRaWANPayloadDecoderLayer:
    Type: AWS::Serverless::LayerVersion
    Properties:
      LayerName: !Sub "${AWS::StackName}-LoRaWANPayloadDecoderLayerDemo"
      Description: Payload decoders for LoRaWAN devices in Python and Node.JS
      ContentUri: src-payload-decoders
      CompatibleRuntimes:
        - python3.8
        - python3.7
        - python3.6
        - nodejs14.x
        - nodejs12.x
        - nodejs14.x
      RetentionPolicy: Retain

  ############################################################################################
  # This IoT Rule converts a binary message to a JSON message using a payload decoder, and then
  # republishes the JSON message.
  # After transformation, the rule will republish the JSON payload to:
  # dt/lorawantransformed
  ############################################################################################

  TransformLoRaWANBinaryPayloadPythonRule:
    Type: "AWS::IoT::TopicRule"
    Condition: IsPythonSupportEnabled
    Properties:
      RuleName: !Sub "${AWS::StackName}_TransformLoRaWANBinaryPayloadPython_${ParamBinaryDecoderName}"
      TopicRulePayload:
        AwsIotSqlVersion: "2016-03-23"
        RuleDisabled: false

        Sql: !Sub
          - |
            SELECT aws_lambda("${LambdaARN}",
                              {"PayloadDecoderName": "${ParamBinaryDecoderName}", 
                              "PayloadData":PayloadData, 
                              "WirelessDeviceId": WirelessDeviceId, 
                               "WirelessMetadata": WirelessMetadata}) as transformed_payload, 
                    WirelessDeviceId as transformed_payload.WirelessDeviceId,                                   
                    WirelessMetadata.LoRaWAN.DevEui as transformed_payload.DevEui,
                    WirelessDeviceId as lns_payload.WirelessDeviceId, 
                    WirelessMetadata as lns_payload.WirelessMetadata,
                    PayloadData as lns_payload.PayloadData,
                    timestamp() as timestamp
          - {
              LambdaARN: !GetAtt TransformLoRaWANBinaryPayloadFunctionPython.Arn,
            }
        Actions:
          - Republish:
              RoleArn: !GetAtt TransformLoRaWANBinaryPayloadRuleActionRole.Arn
              Topic: !Join ["", [!Ref TopicOutgoingTransformedMessages]]
              Qos: 0
        ErrorAction:
          Republish:
            RoleArn: !GetAtt TransformLoRaWANBinaryPayloadRuleActionRole.Arn
            Topic: !Ref TopicOutgoingErrors
            Qos: 0

  ############################################################################################
  # This IoT Rule converts a binary message to a JSON message using a payload decoder, and then
  # republishes the JSON message.
  # After transformation, the rule will republish the JSON payload to:
  # dt/lorawantransformed
  ############################################################################################

  TransformLoRaWANBinaryPayloadNodeRule:
    Type: "AWS::IoT::TopicRule"
    Condition: IsNodeSupportEnabled
    Properties:
      RuleName: !Sub "${AWS::StackName}_TransformLoRaWANBinaryPayloadNode_${ParamBinaryDecoderName}"
      TopicRulePayload:
        AwsIotSqlVersion: "2016-03-23"
        RuleDisabled: false

        Sql: !Sub
          - |
            SELECT aws_lambda("${LambdaARN}",
                              {"PayloadDecoderName": "${ParamBinaryDecoderName}", 
                              "PayloadData":PayloadData, 
                              "WirelessDeviceId": WirelessDeviceId, 
                               "WirelessMetadata": WirelessMetadata}) as transformed_payload, 
                    WirelessDeviceId as transformed_payload.WirelessDeviceId,                                   
                    WirelessMetadata.LoRaWAN.DevEui as transformed_payload.DevEui,
                    WirelessDeviceId as lns_payload.WirelessDeviceId, 
                    WirelessMetadata as lns_payload.WirelessMetadata,
                    PayloadData as lns_payload.PayloadData,
                    timestamp() as timestamp
          - { LambdaARN: !GetAtt TransformLoRaWANBinaryPayloadFunctionNode.Arn }
        Actions:
          - Republish:
              RoleArn: !GetAtt TransformLoRaWANBinaryPayloadRuleActionRole.Arn
              Topic: !Join ["", [!Ref TopicOutgoingTransformedMessages]]
              Qos: 0
        ErrorAction:
          Republish:
            RoleArn: !GetAtt TransformLoRaWANBinaryPayloadRuleActionRole.Arn
            Topic: !Ref TopicOutgoingErrors
            Qos: 0

  TransformLoRaWANBinaryPayloadFunctionPythonPermission:
    Type: AWS::Lambda::Permission
    Condition: IsPythonSupportEnabled
    Properties:
      FunctionName: !GetAtt TransformLoRaWANBinaryPayloadFunctionPython.Arn
      Action: lambda:InvokeFunction
      Principal: iot.amazonaws.com

  TransformLoRaWANBinaryPayloadFunctionNodePermission:
    Type: AWS::Lambda::Permission
    Condition: IsNodeSupportEnabled
    Properties:
      FunctionName: !GetAtt TransformLoRaWANBinaryPayloadFunctionNode.Arn
      Action: lambda:InvokeFunction
      Principal: iot.amazonaws.com

  TransformLoRaWANBinaryPayloadRuleActionRole:
    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/*",
                    ],
                  ]

Outputs:
  IoTRuleNamePython:
    Condition: IsPythonSupportEnabled
    Description: "Please add this AWS IoT Rule name as a Destination to AWS IoT Core for LoRaWAN "
    Value: !Ref TransformLoRaWANBinaryPayloadPythonRule

  IoTRuleNameNode:
    Description: "Please add this AWS IoT Rule name as a Destination to AWS IoT Core for LoRaWAN "
    Condition: IsNodeSupportEnabled
    Value: !Ref TransformLoRaWANBinaryPayloadNodeRule

  TransformPayloadFunctionFunctionPython:
    Condition: IsPythonSupportEnabled
    Description: "Lambda Function ARN python"
    Value: !GetAtt TransformLoRaWANBinaryPayloadFunctionPython.Arn

  TransformPayloadFunctionFunctionNode:
    Description: "Lambda Function ARN node"
    Condition: IsNodeSupportEnabled
    Value: !GetAtt TransformLoRaWANBinaryPayloadFunctionNode.Arn

  TransformPayloadFunctionIamRole:
    Description: "Implicit IAM Role created for Lambda function"
    Value: !GetAtt TransformLoRaWANBinaryPayloadRuleActionRole.Arn
  DecoderLayerARN:
    Value: !Ref LoRaWANPayloadDecoderLayer
    Description: "ARN of payload decoder layer "