<?php

/**
 * @author          Tassos Marinos <info@tassos.gr>
 * @link            https://www.tassos.gr
 * @copyright       Copyright © 2024 Tassos All Rights Reserved
 * @license         GNU GPLv3 <http://www.gnu.org/licenses/gpl.html> or later
*/

// No direct access to this file
defined('_JEXEC') or die;

use Joomla\CMS\Form\Field\ListField;
use Joomla\CMS\Language\Text;
use Joomla\Registry\Registry;
use Tassos\Framework\HTML;

/*
 * Creates an AJAX-based dropdown
 * https://select2.org/
 */
abstract class JFormFieldAjaxify extends ListField
{
    /**
     * Textbox placeholder
     *
     * @var string
     */
    protected $placeholder = 'Select Items';

    /**
     * AJAX rows limit
     *
     * @var int
     */
    protected $limit = 50;

    /**
     * List of options.
     * 
     * @var Registry
     */
    protected $options;

    /**
     * Current page
     * 
     * @var int
     */
    protected $page;

    /**
     * Search term
     * 
     * @var string
     */
    protected $search_term;

    /**
     * Whether to append ID to label
     *
     * @var bool
     */
    protected $append_id_to_label = false;

    /**
     *  Method to render the input field
     *
     *  @return  string
     */
    protected function getInput()
    {   
        if ($this->value && is_string($this->value))
        {
            $this->value = \Tassos\Framework\Functions::makeArray($this->value);
        }

        $isSingle = !isset($this->element['multiple']) || $this->element['multiple'] == 'false';
        $placeholder = (string) $this->element['placeholder'];
        $this->placeholder = empty($placeholder) ? $this->placeholder : $placeholder;

        $searchPlaceholder = isset($this->element['searchPlaceholder']) ? (string) $this->element['searchPlaceholder'] : false;
        
        HTML::stylesheet('plg_system_nrframework/select2.css');
        HTML::script('plg_system_nrframework/vendor/select2.min.js');
        HTML::script('plg_system_nrframework/ajaxify.js');

        return '<div class="tf-ajaxify-wrapper" data-single-value="' . var_export($isSingle, true) . '" data-search-placeholder="' . Text::_($searchPlaceholder) . '" data-placeholder="' . htmlspecialchars(Text::_($this->placeholder)) . '" data-ajax-endpoint="' . $this->getAjaxEndpoint() . '">' . parent::getInput() . '</div>';
    }

    /**
     * Get AJAX endpoint URL
     */
    abstract protected function getAjaxEndpoint();

    /**
     * Method to get the data to be passed to the layout for rendering.
     *
     * @return  array
     */
    protected function getLayoutData()
    {
        $data = parent::getLayoutData();

        $extraData = [
            'class' => 'input-xxlarge select2 tf-select-ajaxify'
        ];

        return array_merge($data, $extraData);
    }

    /**
     * Returns data object used by the AJAX request
     *
     * @param   array    $options
     *
     * @return  array
     */
    public function onAjax($options)
    {
        $this->options = new Registry($options);

        // Reinitialize Field
        $this->element['preset'] = $this->options->get('preset', 'content');
        $this->init();

        $this->limit       = $this->options->get('limit', $this->limit);
        $this->page        = $this->options->get('page', 1);
        $this->search_term = $this->options->get('term');

        $rows = $this->getItems();

        $hasMoreRecords = false;

        if ($this->limit > 0)
        {
            $total = $this->getItemsTotal();
            $hasMoreRecords = ($this->page * $this->limit) < $total;
        }

        $data = [
            'results' => $rows,
            'pagination' => ['more' => $hasMoreRecords]
        ];

        echo json_encode($data);
    }

    /**
     * Load selected options
     *
     * @return void
     */
    protected function getOptions()
    {
        $options = $this->value;

        if (empty($options))
        {
            return;
        }
        
        // In case the value is previously saved in a comma separated format.
        if (!is_array($options))
        {
            $options = explode(',', $options);
        }

        if (!method_exists($this, 'validateOptions'))
        {
            return $options;
        }

        // Remove empty and null items
        $options = array_filter($options);

        try
        {
            return $this->validateOptions($options);
        }
        catch (Exception $e)
        {
            echo $e->getMessage();
        }
    }

    /**
     * Initialize field
     */
    abstract public function init();

    /**
     * This method is called by the onAjax method and must return an array of arrays
     *
     * @return void
     */
    abstract protected function getItems();

    abstract protected function getItemsTotal();
}