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

// ABOUT THIS NODE.JS SAMPLE: This sample is part of the SDK for JavaScript Developer Guide topic at
// https://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/nodejs-write-lambda-function-example-full.html

// NOTE:
// Supporting topics for the above-mentioned topic also contain important information about the role policy when creating the IAM role.

// snippet-start:[lambda.JavaScript.writeLambdaFunction.complete]
// Configuring the AWS SDK
var AWS = require("aws-sdk");
AWS.config.update({ region: "REGION" });

exports.handler = (event, context, callback) => {
  const URL_BASE = "S3_BUCKET_URL";

  // Define the object that will hold the data values returned
  var slotResults = {
    isWinner: false,
    leftWheelImage: { file: { S: "" } },
    middleWheelImage: { file: { S: "" } },
    rightWheelImage: { file: { S: "" } },
  };

  // define parameters JSON for retrieving slot pull data from the database
  var thisPullParams = {
    Key: { slotPosition: { N: "" } },
    TableName: "slotWheels",
    ProjectionExpression: "imageFile",
  };

  // create DynamoDB service object
  var request = new AWS.DynamoDB({
    region: "REGION",
    apiVersion: "2012-08-10",
  });

  // set a random number 0-9 for the slot position
  thisPullParams.Key.slotPosition.N = Math.floor(Math.random() * 15).toString();
  // call DynamoDB to retrieve the image to use for the Left slot result
  var myLeftPromise = request
    .getItem(thisPullParams)
    .promise()
    .then(function (data) {
      return URL_BASE + data.Item.imageFile.S;
    });

  // set a random number 0-9 for the slot position
  thisPullParams.Key.slotPosition.N = Math.floor(Math.random() * 15).toString();
  // call DynamoDB to retrieve the image to use for the Left slot result
  var myMiddlePromise = request
    .getItem(thisPullParams)
    .promise()
    .then(function (data) {
      return URL_BASE + data.Item.imageFile.S;
    });

  // set a random number 0-9 for the slot position
  thisPullParams.Key.slotPosition.N = Math.floor(Math.random() * 15).toString();
  // call DynamoDB to retrieve the image to use for the Left slot result
  var myRightPromise = request
    .getItem(thisPullParams)
    .promise()
    .then(function (data) {
      return URL_BASE + data.Item.imageFile.S;
    });

  Promise.all([myLeftPromise, myMiddlePromise, myRightPromise]).then(function (
    values
  ) {
    slotResults.leftWheelImage.file.S = values[0];
    slotResults.middleWheelImage.file.S = values[1];
    slotResults.rightWheelImage.file.S = values[2];
    // if all three values are identical, the spin is a winner
    if (values[0] === values[1] && values[0] === values[2]) {
      slotResults.isWinner = true;
    }
    // return the JSON result to the caller of the Lambda function
    callback(null, slotResults);
  });
};
// snippet-end:[lambda.JavaScript.writeLambdaFunction.complete]