<?php

class helloChamp{

    function __construct(){


        /*
        * Ajax Requests
        */
        $this->ajax_requests();

    }


    protected function ajax_requests(){


        /*
        * Send somethings
        */
        add_action('wp_ajax_save-something', 'save_something');
        //add_action('wp_ajax_nopriv_save-something', 'save_something');
        function save_something(){

            /*
            * Prevent data you don't want
            */
            $data = $_POST;

            $keys = [
                'action',
                'key',
                'value',
            ];


            if(count($data) !== count($keys)) return;

            foreach($keys as $key){

                if(!isset($data[$key]) || !$data[$key] || empty($data[$key])){

                    echo wp_json_encode([
                        'status' => 'error',
                        'message' => 'Your data doesn\'t respect the requirements.'
                    ]);

                    exit;
                }

            }

            /*
            * Now you sure you have the data you need, make sure the data is like your JS verifications here
            */
            $k = $data['key'];
            $v = $data['value'];

            /*
            * Do your verifications here...
            */
            $error = false;


            /*
            * Ok, verifications are good, save
            */
            if(!$error){

                update_field('field_key', wp_json_encode(
                    [
                        'key' => $k,
                        'value' => $v
                    ]
                ), $post_id);

                echo wp_json_encode([
                    'status' => 'success',
                    'message' => 'Your datas has been saved.'
                ]);

            } else {

                echo wp_json_encode([
                    'status' => 'error',
                    'message' => 'Your can\t be save.'
                ]);

            }


            exit;

        }
    }

}

new helloChamp();

?>