{
    "Description" : "Creates an API gateway which uses a lambda function to forward messages from a push monitor to an IoT analytics channel",
    "Parameters": {
        "ResourceNamePrefix": {
            "Type": "String",
            "Default": "push_monitor_messages_",
            "Description": "A string that will be used as a prefix for the names of created resources."
        },
        "RetentionPeriod": {
            "Type": "Number",
            "Default": 90,
            "Description": "The number of days to store recieved messages"
        }
    },
    "Resources": {
        "pushMonitorApi": {
            "Type": "AWS::ApiGateway::RestApi",
            "Properties": {
                "Name": { "Fn::Join" : ["", [{ "Ref": "ResourceNamePrefix" }, "api_gateway"]] },
                "Description": "A REST API for receiving messages from a push monitor"
            }
        },
        "pushMonitorMethod": {
            "Type": "AWS::ApiGateway::Method",
            "Properties": {
                "ApiKeyRequired": true,
                "AuthorizationType": "NONE",
                "HttpMethod": "POST",
                "Integration": {
                    "Type": "AWS",
                    "IntegrationHttpMethod": "POST",
                    "Uri": { "Fn::Join" : ["", ["arn:aws:apigateway:", { "Ref": "AWS::Region" }, ":lambda:path/2015-03-31/functions/", { "Fn::GetAtt": ["forwardPushMonitorMessagesToChannel", "Arn"] }, "/invocations"]] },
                    "IntegrationResponses": [
                        {
                            "StatusCode": 200
                        }
                    ]
                },
                "MethodResponses": [
                    {
                        "StatusCode": 200
                    }
                ],
                "ResourceId": { "Fn::GetAtt": ["pushMonitorApi", "RootResourceId"] },
                "RestApiId": { "Ref": "pushMonitorApi" }
            }
        },
        "pushMonitorDeploy": {
            "Type": "AWS::ApiGateway::Deployment",
            "DependsOn": ["pushMonitorMethod"],
            "Properties": {
                "StageName": "prod",
                "RestApiId": { "Ref": "pushMonitorApi" }
            }
        },
        "pushMonitorApiKey": {
            "Type": "AWS::ApiGateway::ApiKey",
            "DependsOn": ["pushMonitorDeploy"],
            "Properties": {
                "Name": { "Fn::Join" : ["", [{ "Ref": "ResourceNamePrefix" }, "api_key"]] },
                "Enabled": true,
                "StageKeys": [
                    {
                        "RestApiId": { "Ref": "pushMonitorApi" },
                        "StageName": "prod"
                    }
                ]
            }
        },
        "pushMonitorApiUsagePlan": {
            "Type": "AWS::ApiGateway::UsagePlan",
            "DependsOn": ["pushMonitorDeploy"],
            "Properties": {
                "UsagePlanName": { "Fn::Join" : ["", [{ "Ref": "ResourceNamePrefix" }, "usage_plan"]] },
                "ApiStages": [
                    {
                        "ApiId": { "Ref": "pushMonitorApi" },
                        "Stage": "prod"
                    }
                ]
            }
        },
        "pushMonitorApiUsagePlanKey": {
            "Type": "AWS::ApiGateway::UsagePlanKey",
            "Properties": {
                "KeyId": { "Ref": "pushMonitorApiKey" },
                "KeyType": "API_KEY",
                "UsagePlanId": { "Ref": "pushMonitorApiUsagePlan" }
            }
        },
        "forwardPushMonitorMessagesToChannel": {
            "Type" : "AWS::Lambda::Function",
            "DependsOn": ["pushMonitorMessagesChannel"],
            "Properties" : {
                "Description": "A lambda function that process push monitor messages and forwards them to a AWS Iot Analytics channel",
                "FunctionName": { "Fn::Join" : ["", [{ "Ref": "ResourceNamePrefix" }, "lambda"]] },
                "Code": { "ZipFile": { "Fn::Join" : ["", ["let AWS = require('aws-sdk');\n\nexports.handler = async (event) => {\n\tlet messages = event.Document.Msg;\n\tif (!Array.isArray(messages)) {\n\t\tmessages = [messages];\n\t}\n\n\tlet iotAnalytics = new AWS.IoTAnalytics(); \n\tlet i = 0;\n\tlet msgStrings = messages.map(message => {\n\t\ti++;\n\t\treturn { messageId: i.toString(), payload: JSON.stringify(message) };\n\t});\n\n\treturn await iotAnalytics.batchPutMessage({ channelName: '", { "Ref": "ResourceNamePrefix" }, "channel", "', messages: msgStrings }).promise();\n};"]] } },
                "Handler": "index.handler",
                "Runtime": "nodejs12.x",
                "Role": { "Fn::GetAtt": ["forwardPushMonitorMessagesToChannelRole", "Arn"] }
            }
        },
        "forwardPushMonitorMessagesToChannelRole": {
            "Type": "AWS::IAM::Role",
            "Properties": {
                "RoleName": { "Fn::Join": ["", [{ "Ref": "ResourceNamePrefix" }, "role"]] },
                "AssumeRolePolicyDocument": {
                    "Version": "2012-10-17",
                    "Statement": [
                        {
                            "Effect": "Allow",
                            "Principal": {
                                "Service": "lambda.amazonaws.com"
                            },
                            "Action": "sts:AssumeRole"
                        }
                    ] 
                },
                "Policies": [
                    {
                        "PolicyName": "forwardPushMonitorMessagesToChannelPolicy",
                        "PolicyDocument": {
                            "Version": "2012-10-17",
                            "Statement": [
                                {
                                    "Effect": "Allow",
                                    "Action": ["iotanalytics:BatchPutMessage"],
                                    "Resource": [{ "Fn::Join" : ["", ["arn:", { "Ref": "AWS::Partition" }, ":iotanalytics:", { "Ref": "AWS::Region" }, ":", { "Ref": "AWS::AccountId" }, ":channel/", { "Ref": "ResourceNamePrefix" }, "channel"]] }]
                                }
                            ]
                        }
                    }
                ]
            }
        },
        "forwardPushMonitorMessagesToChannelPermission": {
            "Type": "AWS::Lambda::Permission",
            "Properties": {
                "FunctionName": { "Fn::GetAtt": ["forwardPushMonitorMessagesToChannel", "Arn"] },
                "Action": "lambda:InvokeFunction",
		        "Principal": "apigateway.amazonaws.com",
		        "SourceArn": {  "Fn::Join" : ["", ["arn:", { "Ref": "AWS::Partition" }, ":execute-api:", { "Ref": "AWS::Region" }, ":", { "Ref": "AWS::AccountId" }, ":", { "Ref": "pushMonitorApi" }, "/*/POST/"]] }
            }
        },
        "pushMonitorMessagesChannel": {
            "Type": "AWS::IoTAnalytics::Channel",
            "Properties": {
                "ChannelName": { "Fn::Join" : ["", [{ "Ref": "ResourceNamePrefix" }, "channel"]] },
                "RetentionPeriod": {
                    "NumberOfDays": { "Ref": "RetentionPeriod" }
                }
            }
        },
        "pushMonitorMessagesStore": {
            "Type": "AWS::IoTAnalytics::Datastore",
            "Properties": {
                "DatastoreName": { "Fn::Join" : ["", [{ "Ref": "ResourceNamePrefix" }, "datastore"]] },
                "RetentionPeriod": {
                    "NumberOfDays": { "Ref": "RetentionPeriod" }
                }
            }
        },
        "pushMonitorMessagesPipeline": {
            "Type": "AWS::IoTAnalytics::Pipeline",
            "DependsOn": ["pushMonitorMessagesChannel", "pushMonitorMessagesStore"],
            "Properties": {
                "PipelineName": { "Fn::Join" : ["", [{ "Ref": "ResourceNamePrefix" }, "pipeline"]] },
                "PipelineActivities": [
                    {
                        "Channel": {
                            "Name": "ChannelActivity",
                            "ChannelName": { "Fn::Join" : ["", [{ "Ref": "ResourceNamePrefix" }, "channel"]] },
                            "Next": "DatastoreActivity"
                        },
                        "Datastore": {
                            "Name": "DatastoreActivity",
                            "DatastoreName": { "Fn::Join" : ["", [{ "Ref": "ResourceNamePrefix" }, "datastore"]] }
                        }
                    }
                ]
            }
        },
        "pushMonitorMessagesDataset": {
            "Type": "AWS::IoTAnalytics::Dataset",
            "DependsOn": ["pushMonitorMessagesStore"],
            "Properties": {
                "DatasetName": { "Fn::Join" : ["", [{ "Ref": "ResourceNamePrefix" }, "example_dataset"]] },
                "Actions": [
                    {
                        "ActionName": "SqlAction",
                        "QueryAction": {
                            "SqlQuery": { "Fn::Join" : ["", ["SELECT * from ", { "Ref": "ResourceNamePrefix" }, "datastore"]] }
                        }
                    }
                ]
            }
        }
    }
}