<?php 
add_shortcode('aj_likes_btn', 'aj_likes_btn');
function aj_likes_btn(){
	global $post;

	$post_id = $post->ID;
	$current_count = get_post_meta( $post_id, 'likes',true);
	$current_count = $current_count ? $current_count : 0;
    
    ob_start();
	?>
	<div class='aj_likes'>
		<p><a class='aj_thumbsup' href='' data-id='<?php echo $post_id;?>'>
		    <i class="far fa-thumbs-up"></i></a> 
		    Likes (<span><?php echo $current_count;?></span>)</p>
	</div>
	<?php
	return ob_get_clean();
}

jQuery(document).ready(function($){

$('body').on('click','.aj_thumbsup',function(event){
	event.preventDefault(); // stop click from refreshing page
    
    var OBJ = $(this);
    
    if(OBJ.hasClass('recorded')) return; // stop multiple submissions
    
	var id = $(this).data('id'); // get post ID
	var data_arg = {};
	data_arg['id'] = id;
	data_arg['action'] = 'aj_like_post'; // ajax hook name

	$.ajax({
		beforeSend: function(){},
		type: 'POST',
		url:the_ajax_script.ajaxurl, // Must be updated if adding this to existing
		data: data_arg,dataType:'json',
		success:function(data){
			OBJ.siblings('span').html( data.new_count); // populate with new new_count
			OBJ.addClass('recorded') // mark as thumbsup recorded
			OBJ.find('i').removeClass('far').addClass('fas'); // make thumbs up icon solid
		}
	});
});
});

<?php
define("THEME_DIR", get_template_directory_uri());
wp_enqueue_script( 'aj_script', THEME_DIR . '/aj_script.js', array( 'jquery' ), 1.0, true );
wp_localize_script( 
	'aj_script', // the handle name of the script
	'the_ajax_script', 
	apply_filters('aj_script_data', array( 
		'ajaxurl' => admin_url( 'admin-ajax.php' ) , 
		'postnonce' => wp_create_nonce( 'aj_nonce' )
	))
);

<?php
add_action( 'wp_ajax_aj_like_post', 'aj_record_like_post' );
add_action( 'wp_ajax_nopriv_aj_like_post', 'aj_record_like_post' ); 
// nopriv allows for nonloggedin users to like as well

public function aj_record_like_post(){

	$post_id = sanitize_text_field( $_POST['id']);

	$current_count = get_post_meta( $post_id, 'likes',true);
	$current_count = $current_count ? $current_count : 0;

	$new_count = $current_count + 1; // add one more like

	update_post_meta( $post_id, 'likes', $new_count); // save new count to the post meta

	echo json_encode(array(
		'status'=>'good',
		'new_count'=>$new_count,
	)); exit;
}

.aj_likes{text-align:center; padding:30px 0; font-size:18px;}
.aj_likes a:hover i{transform: scale(1.2);}
.aj_likes a.recorded:hover i{transform: scale(1);}

<?php
class Custom_class{
	public function __construct(){
		add_action('woocommerce_checkout_order_processed', array($this, 'checkout_processed'), 10, 3);
	}

	public function checkout_processed($order_id, $posted_data, $order){

		// get all coupons in cart
		$cc = $order->get_items('coupon');

		// if no coupons used return
		if( !$cc ) return;

		// run through for each coupons used in cart
		foreach($cc  as $cc1){

			// if coupon code is free $5 coupon
			if($cc1->get_code() == 'giftevo2020'){

				// save to user meta 
				update_user_meta( $this->current_user->ID , 'evo_coupon_used_2020', 'giftevo2020');
			}
		}
	}
}
new Custom_class();

<?php
public function dashboard(){
	// GIFT Cash		
	$hide_gift = true;
		
		// check if current user has coupon code in user meta
		$this->current_user = wp_get_current_user();
		$coupon_used = get_user_meta( $this->current_user->ID, 'evo_coupon_used_2020');
		
		// if this use has not used coupon code show special message
		if(!in_array('giftevo2020', $coupon_used) ):
	?>
		<div class='b50' style='    background: linear-gradient(45deg, #ff5b9d, #ff9570); color: #fff;'>
			<h2>Our Gift to You</h2>
			<p style='line-height: 1.3;font-size: 36px;'>$5 Free Cash to Spend</p> 
			<p>Code at checkout: <b>GIFTEVO2020</b></p>
			<p>Use this free cash to purchase any of our addons before Dec. 2nd, 2020</p>
			<p><a class='btn btn_grey' href='https://www.myeventon.com/addons/'>Find Addons</a></p>
		</div>

	<?php endif;  
}

<?php
class Custom_class{
	public function __construct(){
		add_action('woocommerce_checkout_order_processed', array($this, 'checkout_processed'), 10, 3);
		add_action('woocommerce_account_dashboard',array($this,'dashboard') );
	}

	public function checkout_processed($order_id, $posted_data, $order){

		// get all coupons in cart
		$cc = $order->get_items('coupon');

		// if no coupons used return
		if( !$cc ) return;

		// run through for each coupons used in cart
		foreach($cc  as $cc1){

			// if coupon code is free $5 coupon
			if($cc1->get_code() == 'giftevo2020'){

				// save to user meta 
				update_user_meta( $this->current_user->ID , 'evo_coupon_used_2020', 'giftevo2020');
			}
		}		
	}
	public function dashboard(){		

		// GIFT Cash		
		$hide_gift = true;
			
			// check if current user has coupon code in user meta
			$this->current_user = wp_get_current_user();
			$coupon_used = get_user_meta( $this->current_user->ID, 'evo_coupon_used_2020');
			
			// if this use has not used coupon code show special message
			if(!in_array('giftevo2020', $coupon_used) ):
		?>
			<div class='b50' style='    background: linear-gradient(45deg, #ff5b9d, #ff9570); color: #fff;'>
				<h2>Our Gift to You</h2>
				<p style='line-height: 1.3;font-size: 36px;'>$5 Free Cash to Spend</p> 
				<p>Code at checkout: <b>GIFTEVO2020</b></p>
				<p>Use this free cash to purchase any of our addons before Dec. 2nd, 2020</p>
				<p><a class='btn btn_grey' href='https://www.myeventon.com/addons/'>Find Addons</a></p>
			</div>

		<?php endif;  
	}
}
new Custom_class();