<?php

    new my_acf_extension();

    class my_acf_extension
    {
        public function __construct()
        {
            // kalliergeia field on poikilia
            add_action('acf/load_field/key=field_579376941cecc', array($this, 'load_kalliergeia_field_choices'));
            // kalliergeia field on post
            add_action('acf/load_field/key=field_5b5e20e06334b', array($this, 'load_kalliergeia_field_choices'));
            // poikilia field on post
            add_action('acf/load_field/key=field_5b5e20cb6334a', array($this, 'load_poikilia_field_choices'));
            // ajax action for loading poikilia choices
            add_action('wp_ajax_load_poikilia_field_choices', array($this, 'ajax_load_poikilia_field_choices'));
            // enqueue js extension for acf
            // do this when ACF in enqueuing scripts
            add_action('acf/input/admin_enqueue_scripts', array($this, 'enqueue_script'));
        } // end public function __construct

        public function load_kalliergeia_field_choices($field)
        {
            // this funciton dynamically loads the kalliergeia select field choices
            // from the kalliergeia post type

            // I only want to do this on paragogos and poikilia CPT
            global $post;
            if (!$post ||
                !isset($post->ID) ||
                (get_post_type($post->ID) != 'paragogos' && get_post_type($post->ID) != 'poikilia')) {
                return $field;
            }

            // get kalliergeies
            $args = array(
                'post_type' => 'kalliergeia',
                'posts_per_page' => -1,
                'orderby' => 'title',
                'order' => 'ASC'
            );
            $query = new WP_Query($args);
            if (get_post_type($post->ID) == 'paragogos') {
                $choices = array('' => '-- Καλλιέργεια --');
            } // Default value on paragogos CPT
            if (get_post_type($post->ID) == 'poikilia') {
                $choices = array();
            }                           // Empty default value on poikilia CPT
            if (count($query->posts)) {
                // populate choices
                foreach ($query->posts as $kalliergeia) {
                    $choices[$kalliergeia->ID] = $kalliergeia->post_title;
                }
            }
            $field['choices'] = $choices;
            //debug_to_console($field);
            return $field;
        } // end public function load_kalliergeia_field_choices

        public function load_poikilia_field_choices($field)
        {
            // this function dynamically loads poikilia field choices
            // based on the currently saved kalliergeia

            // I only want to do this on paragogos CPT
            global $post;
            if (!$post ||
                !isset($post->ID) ||
                get_post_type($post->ID) != 'paragogos') {
                return $field;
            }
            if (have_rows('kalliergeies')){
              debug_to_console('Have rows');
            }

            return $field;
        } // end public funciton load_poikilia_field_choices

        public function enqueue_script()
        {
            // enqueue acf extenstion

            // only enqueue the script on the post page where it needs to run
            /* *** THIS IS IMPORTANT
                   ACF uses the same scripts as well as the same field identification
                   markup (the data-key attribute) if the ACF field group editor
                   because of this, if you load and run your custom javascript on
                   the field group editor page it can have unintended side effects
                   on this page. It is important to alway make sure you're only
                   loading scripts where you need them.
            */
            global $post;
            if (!$post ||
                !isset($post->ID) ||
                get_post_type($post->ID) != 'paragogos') {
                return;
            }

            $handle = 'acf-kalliergeies';

            // I'm using this method to set the src because
            // I don't know where this file will be located
            // you should alter this to use the correct fundtions
            // to set the src value to point to the javascript file
            $src = '/'.str_replace(ABSPATH, '', dirname(__FILE__)).'/acf-kalliergeies.js';
            // make this script dependent on acf-input
            $depends = array('acf-input');

            wp_enqueue_script($handle, $src, $depends);
        } // end public function enqueue_script

        public function ajax_load_poikilia_field_choices()
        {
            // this funtion is called by AJAX to load poikilies
            // based on kalliergeia selecteion

            // we can use the acf nonce to verify
            if (!wp_verify_nonce($_POST['nonce'], 'acf_nonce')) {
                die();
            }
            $kalliergeia = 0;
            if (isset($_POST['kalliergeia'])) {
                $kalliergeia = intval($_POST['kalliergeia']);
            }
            $poikilies = $this->get_poikilies($kalliergeia);
            $choices = array();
            foreach ($poikilies as $value => $label) {
                $choices[] = array('value' => $value, 'label' => $label);
            }
            echo json_encode($choices);
            exit;
        } // end public function ajax_load_poikilia_field_choices

        private function get_poikilies($post_id)
        {
            // $post_id is post ID of kalliergeia post
            // get all poikilies related to the kalliergeia
            $args = array(
                'post_type' => 'poikilia',
                'posts_per_page' => -1,
                'orderby' => 'title',
                'order' => 'ASC',
                'meta_query' => array(
                    array(
                        'key' => 'kalliergeia',
                         //'value' => $post_id,          // [if acf supports only one value]
                         'value' => '"'.$post_id.'"',  // [if acf supports multiple values]
                         'compare' => 'LIKE'           // [if acf supports multiple values]
                    )
                )
            );
            $query = new WP_Query($args);
            //$choices = array('' => '-- Ποικιλία --');
            $choices = array();
            if (count($query->posts)) {
                // populate choices
                foreach ($query->posts as $post) {
                    $choices[$post->ID] = $post->post_title;
                }
            }
            return $choices;
        } // end private function get_poikilies
    } // end class my_acf_extension