// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
/*
 Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.

 This file is licensed under the Apache License, Version 2.0 (the "License").
 You may not use this file except in compliance with the License. A copy of the
 License is located at

 http://aws.amazon.com/apache2.0/

 This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
 OF ANY KIND, either express or implied. See the License for the specific
 language governing permissions and limitations under the License.
*/

package main

import (
	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/lambda"

	"encoding/json"
	"fmt"
	"os"
	"strconv"
)

type getItemsRequest struct {
	SortBy     string
	SortOrder  string
	ItemsToGet int
}

type getItemsResponseError struct {
	Message string `json:"message"`
}

type getItemsResponseData struct {
	Item string `json:"item"`
}

type getItemsResponseBody struct {
	Result string                 `json:"result"`
	Data   []getItemsResponseData `json:"data"`
	Error  getItemsResponseError  `json:"error"`
}

type getItemsResponseHeaders struct {
	ContentType string `json:"Content-Type"`
}

type getItemsResponse struct {
	StatusCode int                     `json:"statusCode"`
	Headers    getItemsResponseHeaders `json:"headers"`
	Body       getItemsResponseBody    `json:"body"`
}

func main() {
	// Create Lambda service client
	sess := session.Must(session.NewSessionWithOptions(session.Options{
		SharedConfigState: session.SharedConfigEnable,
	}))

	client := lambda.New(sess, &aws.Config{Region: aws.String("us-west-2")})

	// Get the 10 most recent items
	request := getItemsRequest{"time", "descending", 10}

	payload, err := json.Marshal(request)
	if err != nil {
		fmt.Println("Error marshalling MyGetItemsFunction request")
		os.Exit(0)
	}

	result, err := client.Invoke(&lambda.InvokeInput{FunctionName: aws.String("MyGetItemsFunction"), Payload: payload})
	if err != nil {
		fmt.Println("Error calling MyGetItemsFunction")
		os.Exit(0)
	}

	var resp getItemsResponse

	err = json.Unmarshal(result.Payload, &resp)
	if err != nil {
		fmt.Println("Error unmarshalling MyGetItemsFunction response")
		os.Exit(0)
	}

	// If the status code is NOT 200, the call failed
	if resp.StatusCode != 200 {
		fmt.Println("Error getting items, StatusCode: " + strconv.Itoa(resp.StatusCode))
		os.Exit(0)
	}

	// If the result is failure, we got an error
	if resp.Body.Result == "failure" {
		fmt.Println("Failed to get items")
		os.Exit(0)
	}

	// Print out items
	if len(resp.Body.Data) > 0 {
		for i := range resp.Body.Data {
			fmt.Println(resp.Body.Data[i].Item)
		}
	} else {
		fmt.Println("There were no items")
	}
}
