WhatsAppChatComponent.css

.btnIconOverlay {
    position: absolute;
    z-index: 1;
    margin: 0% 0px 0px 88%;
}

WhatsAppChatComponent.html

<template>
    <lightning-card variant="Narrow" >

        <lightning-button if:true={messageList} variant="border-filled"
            label="Chat with another customer" onclick={handleAnOtherChat} slot="actions">
        </lightning-button>

        <lightning-spinner alternative-text="Loading" size="small" if:true={isSpinner}></lightning-spinner>
        <div class="slds-p-horizontal_small">

            <section role="log" class="slds-chat" if:false={messageList}>
                <lightning-input type="tel"
                    message-when-value-missing="Please provide a valid contact no to chat with"
                    required variant="label-hidden" name="Phone"
                    onchange={handlePhoneChange}
                    placeholder="Enter Customer Phone Number and click next">
                </lightning-input>
                <br/>
                <lightning-button variant="brand" label="Chat with Customer" title="Chat with Customer" onclick={handlelistAllMessageByCustomer}></lightning-button>
            </section>

            <section role="log" class="messageContent slds-chat slds-scrollable" if:true={messageList} style="height: 350px;">
                <ul class="slds-chat-list">
                    <template if:true={messageList} for:each={messageList} for:item="message" for:index="index">
                            <!-- Message From Customer -->
                        <li class="slds-chat-listitem slds-chat-listitem_inbound" key={message.Id} if:false={message.Outgoing__c}>
                            <div class="slds-chat-message" if:true={message.MessageContent__c}>
                                <span aria-hidden="true" class="slds-avatar slds-avatar_circle slds-chat-avatar">
                                    <abbr class="slds-avatar__initials slds-avatar__initials_inverse" title={message.CustomerName__c}>AM</abbr>
                                </span>
                                <div class="slds-chat-message__body">
                                    <div class="slds-chat-message__text slds-chat-message__text_inbound">
                                        <span>
                                            <lightning-formatted-rich-text value={message.MessageContent__c}></lightning-formatted-rich-text>
                                        </span>
                                    </div>
                                    <div class="slds-chat-message__meta" aria-label={message.areaLabel}>{message.CustomerName__c} • <lightning-formatted-date-time value={message.CreatedDate} hour="2-digit"></lightning-formatted-date-time></div>
                                </div>
                            </div>
                        </li>
                        <!-- Message From Salesforce -->
                        <li class="slds-chat-listitem slds-chat-listitem_outbound" key={message.Id} if:true={message.Outgoing__c}>
                            <div class="slds-chat-message" if:true={message.MessageContent__c}>
                                <!-- <span aria-hidden="true" class="slds-avatar slds-avatar_circle slds-chat-avatar">
                                    <abbr class="slds-avatar__initials slds-avatar__initials_inverse" title={message.AgentName__c}>AM</abbr>
                                </span> -->
                                <div class="slds-chat-message__body">
                                    <div class="slds-chat-message__text slds-chat-message__text_outbound">
                                        <span>
                                            <lightning-formatted-rich-text value={message.MessageContent__c}></lightning-formatted-rich-text>
                                        </span>
                                    </div>
                                    <div class="slds-chat-message__meta" aria-label={message.areaLabel}>{message.AgentName__c} • <lightning-formatted-date-time value={message.CreatedDate} hour="2-digit"></lightning-formatted-date-time></div>
                                </div>
                            </div>
                        </li>
                    </template>
                </ul>
            </section>
            <div if:true={chatEnabled}>
                <span class="slds-icon_container slds-icon-utility-end_chat slds-chat-icon">
                    <svg class="slds-icon slds-icon_x-small slds-icon-text-default" aria-hidden="true">
                    <use xlink:href="/apexpages/slds/latest/assets/icons/utility-sprite/svg/symbols.svg#chat"></use>
                    </svg>
                </span>
                <p>
                    <lightning-button-icon onclick={handleSendMessage} class="btnIconOverlay" icon-name="utility:send">
                    </lightning-button-icon>
                    <lightning-input message-when-value-missing="Please type a valid messgae before sending it"
                        required value={chatMessage} type="text" class="chat-input"
                        variant="label-hidden" onchange={handleChatChange} name="Message"
                        placeholder="type here...">
                    </lightning-input>
                </p>
            </div>
        </div>
        <div slot="footer">
            Powered by <a href="https://www.pantherschools.com/" target="_blank" aria-label="Panther Schools">@PantherSchools.com</a>
        </div>
    </lightning-card>
</template>

WhatsAppChatComponent.js

import { api, LightningElement, track } from 'lwc';

import listAllMessageByCustomer from '@salesforce/apex/WhatsAppLWCService.listAllMessageByCustomer';
import sendTextMessage from '@salesforce/apex/WhatsAppLWCService.sendTextMessage';
import getSingleMessage from '@salesforce/apex/WhatsAppLWCService.getSingleMessage';
import { subscribe, onError } from 'lightning/empApi';

export default class WhatsAppChatComponent extends LightningElement {
    
    @api recordId;

    @track messageList;
    @track errors;

    channelName = '/event/WAMessageEvent__e';

    subscription = {};

    chatMessage
    customerNo;
    isSpinner = false;
    chatEnabled = false;

    handleChatChange(event){
        event.preventDefault();
        this.chatMessage = event.target.value;
    }

    connectedCallback(){
        this.registerErrorListener();
        this.handleSubscribe();
    }

    handlelistAllMessageByCustomer(event){
        event.preventDefault();
        if(!this.handleValidate()){
            return;
        }
        this.isSpinner = true;
        listAllMessageByCustomer({
            customerPhone : this.customerNo
        })
        .then(result => {
            this.messageList =  result.map(item => {
                return {
                    ...item,
                    areaLabel: item.Outgoing__c ? `${item.AgentName__c} said at ${item.CreatedDate}` : `${item.CustomerName__c} said at ${item.CreatedDate}`
                }
            });
            this.chatEnabled = true;
        })
        .catch(error => {
            console.error('Error:', error);
            this.errors = error;
        })
        .finally(()=>{
            this.chatEnabled = true;
            console.log('turing off the spinner');
            const chatArea = this.template.querySelector('.messageContent');
            if(chatArea){
                chatArea.scrollTop = chatArea.scrollHeight
            }
            this.isSpinner = false;
            
            this.setUpChatMessage();
        })
    }

    setUpChatMessage(){
        let chatInput = this.template.querySelector(".chat-input");
        if(chatInput){
            chatInput.addEventListener("keydown", (event) => {
                console.log(`Enent handler added`)
                if (event.key === "Enter") {
                    this.handleSendMessage();
                }
            });
        }
    }

    handleSendMessage(){
        
        console.log('Enter Clicked ', this.chatMessage );
        if(!this.handleValidate()){
            return;
        }
        this.isSpinner = true;
        console.log(this.customerNo);
        sendTextMessage({
            messageContent : this.chatMessage,
            toPhone : this.customerNo
        })
        .then(result => {
            console.log(' message list ', result );
            this.chatMessage = '';
            this.messageList = [...this.messageList, result];
            console.log(' Updated Message from ', this.messageList );
        })
        .catch(error => {
            // TODO Error handling
        })
        .finally(()=>{
            console.log('turing off the spinner');
            this.isSpinner = false;
        })
    }

    handlePhoneChange(event){
        this.customerNo = event.target.value;
    }

    handleAnOtherChat(event){
        event.preventDefault();
        this.messageList = undefined;
        this.chatEnabled = false;
    }

    handleValidate(){
        const allValid = [
            ...this.template.querySelectorAll('lightning-input'),
        ].reduce((validSoFar, inputCmp) => {
            inputCmp.reportValidity();
            return validSoFar && inputCmp.checkValidity();
        }, true);
        return allValid;
    }

    registerErrorListener() {
        // Invoke onError empApi method
        onError((error) => {
            console.log('Received error from server: ', JSON.stringify(error));
            // Error contains the server-side error
        });
    }

    handleSubscribe() {
        // Callback invoked whenever a new event message is received
        const messageCallback = this.handleEventResponse.bind(this);

        // Invoke subscribe method of empApi. Pass reference to messageCallback
        subscribe(this.channelName, -1, messageCallback).then((response) => {
            this.subscription = response;
        });
    }

    handleEventResponse(response) {
        console.log('New message received: ', JSON.stringify(response));
        let payload = response.data.payload;
        let MessageId = payload.MessageId__c;
        let CustomerPhone = payload.CustomerPhone__c;
        
        if(this.customerNo === CustomerPhone){
            getSingleMessage({
                recordId : MessageId,
                customerPhone : CustomerPhone
            })
            .then(result => {
                this.messageList = [...this.messageList, result];
                const chatArea = this.template.querySelector('.messageContent');
                if(chatArea){
                    chatArea.scrollTop = chatArea.scrollHeight
                }
            })
            .catch(error => {
                // TODO Error handling
                console.error(error);

            });
        }
    }
}

WhatsAppLWCService.java

public class WhatsAppLWCService {

    @AuraEnabled
    public static sObject getCustomerPhone(String Query){
        return Database.query(Query);
    }

    @AuraEnabled//(cacheable=true)
    public static List<WAMessage__c> listAllMessages(String customerPhone){
        List<WAMessage__c> messages = new List<WAMessage__c>();
        messages = [SELECT Id, Name, MessageContent__c, MessageType__c, CustomerName__c, AgentName__c, Outgoing__c, CreatedDate
                    FROM WAMessage__c
                    WHERE CustomerPhone__c =: customerPhone
                    Order By CreatedDate ASC
                ];
        return messages;
    }

    @AuraEnabled
    public static WAMessage__c getSingleMessage(String recordId, String customerPhone){
        return [SELECT Id, Name, MessageContent__c, MessageType__c, CustomerName__c, AgentName__c, Outgoing__c, CreatedDate
                    FROM WAMessage__c
                    WHERE Id =: recordId AND 
                    CustomerPhone__c =: customerPhone
                Order By CreatedDate ASC
            ];
    }
    
    @AuraEnabled
    public static WAMessage__c sendTextMessage(String messageContent, String toPhone){
        WAMessage__c message = WhatsAppUtils.sendTextMessage(messageContent, toPhone);
        return [SELECT Id, Name, MessageContent__c, MessageType__c, CustomerName__c, AgentName__c, Outgoing__c, CreatedDate
                FROM WAMessage__c
                WHERE Id =: message.Id
                Order By CreatedDate ASC
            ];
    }
    
    @AuraEnabled(cacheable=true) 
    public static List<WAMessage__c> listAllMessageByCustomer(String customerPhone){
        List<WAMessage__c> messages = new List<WAMessage__c>();
        messages = [SELECT Id, Name, MessageContent__c, MessageType__c, CustomerName__c, AgentName__c, Outgoing__c, CreatedDate
                    FROM WAMessage__c 
                    WHERE CustomerPhone__c =: customerPhone 
                    Order By CreatedDate ASC
                ];
        return messages;
    }
}

WhatsAppMessage.java

public class WhatsAppMessage {
    
    public entry[] entry;
    public class entry {
        public String id;	
        public changes[] changes;
    }
    public class changes {
        public value value;
        public String field;	
    }
    public class value {
        public String messaging_product;	
        public metadata metadata;
        public contacts[] contacts;
        public messages[] messages;
    }
    public class metadata {
        public String display_phone_number;	
        public String phone_number_id;	
    }
    public class contacts {
        public profile profile;
        public String wa_id;	
    }
    public class profile {
        public String name;	
    }
    public class messages {
        public context context;
        public String fromx;	
        public String id;	
        public String timestamp;	
        public text text;
        public String typex;	
        public reaction reaction;
        public image image;
        public image video;
    }
    public class context {
        public String fromx;	
        public String id;	
    }
    public class text {
        public String body;	
    }
    public class reaction{
        public String emoji;
        public String message_id;
    }
    public class image{
        public String mime_type;
        public String id;
        public String sha256;
        public String caption;
    }

    /* Class for the Document Message */
    public class document{
        public String mime_type;
        public String filename;
        public String sha256;
        public String id;
    }

    /* Check if the user has clicked on any button */
    public class button {
        public String payload;
        public String text;
    }
}

WhatsAppUtils.java

public class WhatsAppUtils {
    
    public static List<WAMessage__c> listAllMessageByCustomer(String customerPhone){
        List<WAMessage__c> messages = new List<WAMessage__c>();
        messages = [SELECT Id, Name, MessageContent__c, MessageType__c, Outgoing__c FROM WAMessage__c WHERE CustomerPhone__c =: customerPhone];
        return messages;
    }
    public static WAMessage__c sendTextMessage(String messageContent, String toPhone){
        
        HttpRequest httpReq = new HttpRequest();
        httpReq.setEndpoint('https://graph.facebook.com/v13.0/YOUR_ACCOUNT_ID/messages');
        httpReq.setMethod('POST');
        httpReq.setHeader('Content-Type', 'application/json');
        httpReq.setHeader('Authorization', 'Bearer '+System.Label.WHATSAPPACCESSTOKEN);
        
        String messageBody = '{'+
		'    "messaging_product": "whatsapp",'+
		'    "recipient_type": "individual",'+
		'    "to": "'+toPhone+'",'+
		'    "type": "text",'+
		'    "text": {'+
		'        "preview_url": false,'+
		'        "body": "'+messageContent+'"'+
		'    }'+
		'}';
        
        httpReq.setBody(messageBody);
        
        Http http = new Http();
        WAMessage__c salesforceMessage = new WAMessage__c();
        try{
            HttpResponse response = http.send(httpReq);
            if( response.getStatusCode() == 200 ){
                // Parse & Create Message Record
                System.debug('Successful!');
                WhatsAppUtils responseFromWA = (WhatsAppUtils) JSON.deserialize( response.getBody() , WhatsAppUtils.class);
                
                salesforceMessage.MessageContent__c = messageContent;
                salesforceMessage.CustomerPhone__c = toPhone;
                salesforceMessage.MessageID__c = responseFromWA.messages.get(0).id;
                salesforceMessage.MessageType__c = 'text';
                salesforceMessage.Outgoing__c = True;
                salesforceMessage.AgentName__c = UserInfo.getFirstName()+' '+ UserInfo.getLastName();
                upsert salesforceMessage MessageID__c;
            }
        }catch(System.CalloutException ex){
            System.debug(' CalloutException Executed '+ ex.getStackTraceString() );
            System.debug(' CalloutException Executed '+ ex.getMessage() );
        }catch(System.Exception ex){
            System.debug(' System.Exception Executed '+ ex.getStackTraceString() );
        }
        return salesforceMessage;
    }

    
    public static WAMessage__c sendFlightBookingConfirmationMessage(String toPhone, String name, String source, String destination){
        String body = '{'+
		'    "messaging_product": "whatsapp",'+
		'    "recipient_type": "individual",'+
		'    "to": "'+toPhone+'",'+
		'    "type": "template",'+
		'    "template": {'+
		'        "name": "flight_booking_confirm_template",'+
		'        "language": {'+
		'            "code": "en"'+
		'        },'+
		'        "components": ['+
		'            {'+
		'                "type": "header",'+
		'                "parameters": ['+
		'                    {'+
		'                        "type": "image",'+
		'                        "image": {'+
		'                            "link": "https://bit.ly/3AWkh2p"'+
		'                        }'+
		'                    }'+
		'                ]'+
		'            },'+
		'            {'+
		'                "type": "body",'+
		'                "parameters": ['+
		'                    {'+
		'                        "type": "text",'+
		'                        "text": "'+Name+'"'+
		'                    },'+
		'                    {'+
		'                        "type": "text",'+
		'                        "text": "'+source+'"'+
		'                    },'+
		'                    {'+
		'                        "type": "text",'+
		'                        "text": "'+destination+'"'+
		'                    },'+
		'                    {'+
		'                        "type": "date_time",'+
		'                        "date_time" : {'+
		'                            "fallback_value": "October 25, 2023 22:34 PM",'+
		'                            "day_of_week": 6,'+
		'                            "day_of_month": 25,'+
		'                            "year": 2023,'+
		'                            "month": 10,'+
		'                            "hour": 12,'+
		'                            "minute": 34'+
		'                        }'+
		'                    },'+
		'                    {'+
		'                        "type": "text",'+
		'                        "text": "999-999-9999"'+
		'                    }'+
		'                ]'+
		'            },'+
		'            {'+
		'                "type": "button",'+
		'                "sub_type": "quick_reply",'+
		'                "index": "0",'+
		'                "parameters": ['+
		'                    {'+
		'                        "type": "payload",'+
		'                        "payload": "Contact to Support"'+
		'                    }'+
		'                ]'+
		'            },'+
		'            {'+
		'                "type": "button",'+
		'                "sub_type": "quick_reply",'+
		'                "index": "1",'+
		'                "parameters": ['+
		'                    {'+
		'                        "type": "payload",'+
		'                        "payload": "Check PNR Status"'+
		'                    }'+
		'                ]'+
		'            }'+
		'        ]'+
		'    }'+
		'}';

        HttpRequest httpReq = new HttpRequest();
        httpReq.setEndpoint('https://graph.facebook.com/v13.0/YOUR_ACCOUNT_ID/messages');
        httpReq.setMethod('POST');
        httpReq.setHeader('Content-Type', 'application/json');
        httpReq.setHeader('Authorization', 'Bearer '+System.Label.WHATSAPPACCESSTOKEN);
        
        httpReq.setBody(body);
        
        Http http = new Http();
        WAMessage__c salesforceMessage = new WAMessage__c();
        try{
            HttpResponse response = http.send(httpReq);
            if( response.getStatusCode() == 200 ){
                // Parse & Create Message Record
                System.debug('Successful!');
                WhatsAppUtils responseFromWA = (WhatsAppUtils) JSON.deserialize( response.getBody() , WhatsAppUtils.class);
                
                salesforceMessage.MessageContent__c = body;
                salesforceMessage.CustomerPhone__c = toPhone;
                salesforceMessage.MessageID__c = responseFromWA.messages.get(0).id;
                salesforceMessage.MessageType__c = 'template';
                salesforceMessage.Outgoing__c = True;
                salesforceMessage.AgentName__c = UserInfo.getFirstName()+' '+ UserInfo.getLastName();
                upsert salesforceMessage MessageID__c;
            }
        }catch(System.CalloutException ex){
            System.debug(' CalloutException Executed '+ ex.getStackTraceString() );
            System.debug(' CalloutException Executed '+ ex.getMessage() );
        }catch(System.Exception ex){
            System.debug(' System.Exception Executed '+ ex.getStackTraceString() );
        }
        return salesforceMessage;
    }

	public static WAMessage__c sendMediaMessages(String toPhone, String url){
		HttpRequest httpReq = new HttpRequest();
        httpReq.setEndpoint('https://graph.facebook.com/v13.0/YOUR_ACCOUNT_ID/messages');
        httpReq.setMethod('POST');
        httpReq.setHeader('Content-Type', 'application/json');
        httpReq.setHeader('Authorization', 'Bearer '+System.Label.WHATSAPPACCESSTOKEN);
        
		if(String.isBlank(url)){
			url = '';
		}

		String body = '{'+
		'    "messaging_product": "whatsapp",'+
		'    "recipient_type": "individual",'+
		'    "to": "'+toPhone+'",'+
		'    "type": "document",'+
		'    "document": {'+
		'        "link": "'+url+'",'+
		'        "caption" : "Field Service Lightning Topics.pdf",'+
		'        "filename" : "Field Service Lightning Topics.pdf"'+
		'    }'+
		'}';

        httpReq.setBody(body);
        
        Http http = new Http();
        WAMessage__c salesforceMessage = new WAMessage__c();
        try{
            HttpResponse response = http.send(httpReq);
            if( response.getStatusCode() == 200 ){
                // Parse & Create Message Record
                System.debug('Successful!');
                WhatsAppUtils responseFromWA = (WhatsAppUtils) JSON.deserialize( response.getBody() , WhatsAppUtils.class);
                
                salesforceMessage.MessageContent__c = body;
                salesforceMessage.CustomerPhone__c = toPhone;
                salesforceMessage.MessageID__c = responseFromWA.messages.get(0).id;
                salesforceMessage.MessageType__c = 'media';
                salesforceMessage.Outgoing__c = True;
                salesforceMessage.AgentName__c = UserInfo.getFirstName()+' '+ UserInfo.getLastName();
                upsert salesforceMessage MessageID__c;
            }
        }catch(System.CalloutException ex){
            System.debug(' CalloutException Executed '+ ex.getStackTraceString() );
            System.debug(' CalloutException Executed '+ ex.getMessage() );
        }catch(System.Exception ex){
            System.debug(' System.Exception Executed '+ ex.getStackTraceString() );
        }
        return salesforceMessage;
	}
    
    public String messaging_product;
	public contacts[] contacts;
	public messages[] messages;
	public class contacts {
		public String input;
		public String wa_id;
	}
	public class messages {
		public String id;
	}
}

WhatsAppWebhook.java

@RestResource(urlMapping='/whatsapp/webhooks/v1/*')
global without sharing class WhatsAppWebhook {
    
    private static Final String SIGNATURE_VALID_MESSAGE     = 'Signature Verified';
    private static Final String SIGNATURE_NOT_VALID_MESSAGE = 'Signature could not be verified';
    
    @HttpGet // GET
    global static void doGet() {
        RestResponse response = RestContext.response;
        RestRequest request = RestContext.request;
        if(request.params.get('hub.verify_token') == 'WHATSAPPTOKEN'){
            response.responseBody = Blob.valueOf( request.params.get('hub.challenge') );
        }
    }
    
    @HttpPost // POST
    global static void doPost() {
        
        RestResponse response = RestContext.response;
        response.addHeader('Content-type','application/json');
        String responseString = RestContext.request.requestBody.toString();
        Map<String, String> headers = RestContext.request.headers;
        String responseValid = validateWhatsAppSignature(RestContext.request, responseString);
        
        if(responseValid == SIGNATURE_VALID_MESSAGE){
            System.debug(System.LoggingLevel.DEBUG, ' Headers Response From WhatsApp \n  '+ JSON.serialize(headers) );
            System.debug(System.LoggingLevel.DEBUG, ' Response From WhatsApp \n  '+ responseString);
            String finalResponseString = responseString.replace('type', 'typex');
            WhatsAppMessage parentMessage = (WhatsAppMessage)JSON.deserialize( finalResponseString, WhatsAppMessage.class);
            List<WhatsAppMessage.entry> messageEntries = parentMessage.entry;
            if(messageEntries != null && messageEntries.size() > 0){
                WhatsAppMessage.entry entryMessage = messageEntries.get(0);
                List<WhatsAppMessage.changes> changeMessages = entryMessage.changes;
                if(changeMessages != null && changeMessages.size() > 0){
                    WhatsAppMessage.changes changeMessage = changeMessages.get(0);
                    List<WhatsAppMessage.contacts> contactList = changeMessage.value.contacts;
                    List<WhatsAppMessage.messages> messageList = changeMessage.value.messages;
                    WhatsAppMessage.metadata metadata = changeMessage.value.metadata;
                    /* Create record into Salesforce */
                    WAMessage__c salesforceMessage = new WAMessage__c();
                    salesforceMessage.BusinessPhoneNumber__c = metadata != null ? metadata.display_phone_number : null;
                    
                    if(contactList != null && contactList.size() > 0){
                        WhatsAppMessage.contacts contact = contactList.get(0);
                        salesforceMessage.CustomerPhone__c = contact.wa_id;
                        salesforceMessage.CustomerName__c = contact.profile.name;
                    }
                    
                    if(messageList != null && messageList.size() > 0){
                        /* Simple Message */
                        WhatsAppMessage.messages message = messageList.get(0);
                        salesforceMessage.MessageID__c = message.id;
                        salesforceMessage.MessageType__c = message.typex;
                        salesforceMessage.MessageSentTime__c = System.now();
                        salesforceMessage.MessageContent__c = message.text != null? message.text.body : null;
                        
                        /* If message is reaction */
                        salesforceMessage.Reaction__c = message.reaction != null ? message.reaction.emoji : null;
                        salesforceMessage.ParentMessageID__c = message.reaction != null ? message.reaction.message_id : null;
                        
                        /* If message is Image */
                        salesforceMessage.ImageID__c = message.image != null ? message.image.id : null;
                        salesforceMessage.ImageType__c = message.image != null ? message.image.mime_type : null;
                        salesforceMessage.ImageSHA256__c = message.image != null ? message.image.sha256 : null;
                        
                        /* If message is Video */
                        salesforceMessage.VideoId__c = message.video != null ? message.video.id : null;
                        salesforceMessage.VideoType__c = message.video != null ? message.video.mime_type : null;
                        salesforceMessage.VideoSHA256__c = message.video != null ? message.video.sha256 : null;

                        /* If message is Document */
                        
                        /* If the message is reply to another message */
                        salesforceMessage.ParentMessageID__c = message.context != null ? message.context.id : null;
                        
                        upsert salesforceMessage MessageID__c;
                        
                        /* Publish the Platform Event to be listened by LWC */
                        WA_Message_Event__e platformEvent = new WA_Message_Event__e();
                        platformEvent.Message_Id__c = salesforceMessage.Id;
                        platformEvent.Customer_Phone__c = salesforceMessage.CustomerPhone__c;
                        Eventbus.publish( platformEvent );
                        
                    }
                    
                }
            }
        }else{
            response.responseBody = Blob.valueOf('{success:false, event:"Unknown","message:"'+responseValid+'"}');
            response.statusCode = 401;
            return;
        }
        
        response.statusCode = 200;
        response.responseBody = Blob.valueOf('{success:true, event:"success"}');
    }
    
    private static String validateWhatsAppSignature(RestRequest request, String responseString) {
        // Validate Stripe signature Start 
        Map<String, String> headers = request.headers;
        
        String whatsAppSignature = headers.get('X-Hub-Signature-256');
        
        String whatsAppPayload = RestContext.request.requestBody.toString();
        
        // Verify the signature using 'hmacSHA256'. I have the Webhook key stored in a Custom Label
        String whatsAppSecret = System.Label.WHATSAPPSECRET; // Facebook Application Secret Key
        Blob signedPayload = Crypto.generateMac('hmacSHA256', Blob.valueOf(whatsAppPayload), Blob.valueOf( whatsAppSecret ));
        
        String encodedPayload = 'sha256='+EncodingUtil.convertToHex(signedPayload);
        // Return status code based on whether signed payload matches or not
        
        String response = (encodedPayload == whatsAppSignature)? SIGNATURE_VALID_MESSAGE : SIGNATURE_NOT_VALID_MESSAGE;
        return response;
        // Validate Stripe signature End 
    }
}