/**
 * This sample demonstrates a simple skill built with the Amazon Alexa Skills Kit.
 * The Intent Schema, Custom Slots, and Sample Utterances for this skill, as well as
 * testing instructions are located at http://amzn.to/1LzFrj6
 *
 * For additional samples, visit the Alexa Skills Kit Getting Started guide at
 * http://amzn.to/1LGWsLG
 */

var AWS = require('aws-sdk');
AWS.config.region = "us-east-1";
var iotData = new AWS.IotData({endpoint: "a2zweh2b7yb784.iot.us-east-1.amazonaws.com"});

// Route the incoming request based on type (LaunchRequest, IntentRequest,
// etc.) The JSON body of the request is provided in the event parameter.
exports.handler = function (event, context) {
    try {
        console.log("event.session.application.applicationId=" + event.session.application.applicationId);

        /**
         * Uncomment this if statement and populate with your skill's application ID to
         * prevent someone else from configuring a skill that sends requests to this function.
         */
        /*
        if (event.session.application.applicationId !== "amzn1.echo-sdk-ams.app.[unique-value-here]") {
             context.fail("Invalid Application ID");
        }
        */

        if (event.session.new) {
            onSessionStarted({requestId: event.request.requestId}, event.session);
        }

        if (event.request.type === "LaunchRequest") {
            onLaunch(event.request,
                event.session,
                function callback(sessionAttributes, speechletResponse) {
                    context.succeed(buildResponse(sessionAttributes, speechletResponse));
                });
        } else if (event.request.type === "IntentRequest") {
            onIntent(event.request,
                event.session,
                function callback(sessionAttributes, speechletResponse) {
                    context.succeed(buildResponse(sessionAttributes, speechletResponse));
                });
        } else if (event.request.type === "SessionEndedRequest") {
            onSessionEnded(event.request, event.session);
            context.succeed();
        }
    } catch (e) {
        context.fail("Exception: " + e);
    }
};

/**
 * Called when the session starts.
 */
function onSessionStarted(sessionStartedRequest, session) {
    console.log("onSessionStarted requestId=" + sessionStartedRequest.requestId +
        ", sessionId=" + session.sessionId);
}

/**
 * Called when the user launches the skill without specifying what they want.
 */
function onLaunch(launchRequest, session, callback) {
    console.log("onLaunch requestId=" + launchRequest.requestId +
        ", sessionId=" + session.sessionId);

    // Dispatch to your skill's launch.
    getWelcomeResponse(callback);
}

/**
 * Called when the user specifies an intent for this skill.
 */
function onIntent(intentRequest, session, callback) {
    console.log("onIntent requestId=" + intentRequest.requestId +
        ", sessionId=" + session.sessionId);

    var intent = intentRequest.intent,
        intentName = intentRequest.intent.name;

    // Dispatch to your skill's intent handlers
    if ("ControlLight" === intentName) {
        setLightInSession(intent, session, callback);
    } else if ("AMAZON.HelpIntent" === intentName) {
        getWelcomeResponse(callback);
    } else if ("AMAZON.StopIntent" === intentName || "AMAZON.CancelIntent" === intentName) {
        handleSessionEndRequest(callback);
    } else {
        throw "Invalid intent";
    }
}

/**
 * Called when the user ends the session.
 * Is not called when the skill returns shouldEndSession=true.
 */
function onSessionEnded(sessionEndedRequest, session) {
    console.log("onSessionEnded requestId=" + sessionEndedRequest.requestId +
        ", sessionId=" + session.sessionId);
    // Add cleanup logic here
}

// --------------- Functions that control the skill's behavior -----------------------

function getWelcomeResponse(callback) {
    // If we wanted to initialize the session to have some attributes we could add those here.
    var sessionAttributes = {};
    var cardTitle = "Welcome";
    var speechOutput = "Welcome to the Ameba Controller example. " +
        "Please tell me next action by saying, turn on the light";

    // If the user either does not reply to the welcome message or says something that is not
    // understood, they will be prompted again with this text.
    var repromptText = "Please tell me next action by saying, turn on the light";
    var shouldEndSession = false;

    callback(sessionAttributes,
        buildSpeechletResponse(cardTitle, speechOutput, repromptText, shouldEndSession));
}

function handleSessionEndRequest(callback) {
    var cardTitle = "Session Ended";
    var speechOutput = "Thank you for trying the Ameba Controller example. Have a nice day!";
    // Setting this to true ends the session and exits the skill.
    var shouldEndSession = true;

    callback({}, buildSpeechletResponse(cardTitle, speechOutput, null, shouldEndSession));
}

/**
 * Sets the led in the session and prepares the speech to reply to the user.
 */
function setLightInSession(intent, session, callback) {
    var cardTitle = intent.name;
    var lightStateRequest = intent.slots.LightState;
    var repromptText = "";
    var sessionAttributes = {};
    var shouldEndSession = true;
    var speechOutput = "";

    if (lightStateRequest) {
        var lightState = lightStateRequest.value;
        var paramsUpdate;

        if (lightState === "on") {
            paramsUpdate = {
                "thingName" : "ameba",
                "payload" : '{"state": {"desired": {"led":1}}}'
            };
        } else {
            paramsUpdate = {
                "thingName" : "ameba",
                "payload" : '{"state": {"desired": {"led":0}}}'
            };
        }

    //Update Device Shadow
    iotData.updateThingShadow(paramsUpdate, function(err, data) {
      if (err){
        console.log(err, err.stack);

        speechOutput = "fail to update thing shadow";
        repromptText = "fail to update thing shadow";
        callback(sessionAttributes,buildSpeechletResponse(cardTitle, speechOutput, repromptText, shouldEndSession));
      }
      else {
        console.log(data);

            sessionAttributes = createLightStateAttributes(lightState);
                speechOutput = "I now know you want to turn " + lightState + " the light";
                repromptText = "I now know you want to turn " + lightState + " the light";
                callback(sessionAttributes,buildSpeechletResponse(cardTitle, speechOutput, repromptText, shouldEndSession));
      } 
    });
    } else {
        speechOutput = "Please try again";
        repromptText = "Please try again";
        callback(sessionAttributes,buildSpeechletResponse(cardTitle, speechOutput, repromptText, shouldEndSession));
    }
}

function createLightStateAttributes(lightState) {
    return {
        lightState: lightState
    };
}

// --------------- Helpers that build all of the responses -----------------------

function buildSpeechletResponse(title, output, repromptText, shouldEndSession) {
    return {
        outputSpeech: {
            type: "PlainText",
            text: output
        },
        card: {
            type: "Simple",
            title: "SessionSpeechlet - " + title,
            content: "SessionSpeechlet - " + output
        },
        reprompt: {
            outputSpeech: {
                type: "PlainText",
                text: repromptText
            }
        },
        shouldEndSession: shouldEndSession
    };
}

function buildResponse(sessionAttributes, speechletResponse) {
    return {
        version: "1.0",
        sessionAttributes: sessionAttributes,
        response: speechletResponse
    };
}