<?php

declare(strict_types=1);

namespace Atk4\Ui\Form\Control;

use Atk4\Ui\Form;
use Atk4\Ui\HtmlTemplate;
use Atk4\Ui\Js\Jquery;
use Atk4\Ui\Js\JsCallbackLoadableValue;
use Atk4\Ui\Js\JsExpressionable;
use Atk4\Ui\JsCallback;
use Atk4\Ui\View;

/**
 * Display items in a hierarchical (tree) view structure.
 *
 * When an item contains nodes with non empty values, it will automatically be treat as a group level;
 *
 * The input value is store as an array type when allowMultiple is set to true, otherwise, will
 * store one single value when set to false.
 *
 * Only item ID are store within the input field.
 *
 * See demos/form-control/tree-item-selector.php to see how tree items are build.
 */
class TreeItemSelector extends Form\Control
{
    /** @var HtmlTemplate|null Template for the item selector view. */
    public $itemSelectorTemplate;

    /** @var View|null The tree item selector View. */
    public $itemSelector;

    /**
     * The CSS class selector for where to apply loading class name.
     * Loading class name is set during on Item callback.
     *
     * @var string
     */
    public $loaderCssName = 'atk-tree-loader';

    /** @var bool Allow multiple selection or just one. */
    public $allowMultiple = true;

    /**
     * The list of items.
     * Item must have at least one name and one ID.
     * Only the ID value, from a single node, are returned i.e. not the group ID value.
     *
     * Each item may have it's own children by adding nodes children to it.
     * $items = [
     *     ['name' => 'Electronics', 'id' => 'P100', 'nodes' => [
     *         ['name' => 'Phone', 'id' => 'P100', 'nodes' => [
     *             ['name' => 'iPhone', 'id' => 502],
     *             ['name' => 'Google Pixels', 'id' => 503],
     *         ]],
     *         ['name' => 'Tv', 'id' => 501],
     *         ['name' => 'Radio', 'id' => 601],
     *     ]],
     *     ['name' => 'Cleaner', 'id' => 201],
     *     ['name' => 'Appliances', 'id' => 301],
     * ];
     *
     * When adding nodes array into an item, it will automatically be treated as a group unless empty.
     *
     * @var list<array{name: string, id: mixed, nodes?: list<array<string, mixed>>}>
     */
    public $treeItems = [];

    /** @var JsCallback|null Callback for onTreeChange. */
    private $cb;

    #[\Override]
    protected function init(): void
    {
        parent::init();

        $this->addClass(['ui', 'vertical', 'segment', 'basic', $this->loaderCssName])->setStyle(['padding' => '0px!important']);

        if (!$this->itemSelectorTemplate) {
            $this->itemSelectorTemplate = new HtmlTemplate('<div class="ui list" style="margin-left: 16px;" {$attributes}><atk-tree-item-selector v-bind="initData"></atk-tree-item-selector><div class="ui hidden divider"></div>{$Input}</div>');
        }

        $this->itemSelector = View::addTo($this, ['template' => $this->itemSelectorTemplate]);
    }

    public function getInputTag(): string
    {
        return $this->getApp()->getTag('input/', [
            'name' => $this->shortName,
            'type' => 'hidden',
            'value' => $this->getInputValue(),
        ]);
    }

    /**
     * Provide a function to be executed when clicking an item in tree selector.
     * The executing function will receive an array with item state in it
     * when allowMultiple is true or a single value when false.
     *
     * @param \Closure(mixed): (JsExpressionable|View|string|void) $fx
     */
    public function onItem(\Closure $fx): void
    {
        $this->cb = JsCallback::addTo($this)->set(static function (Jquery $j, $value) use ($fx) {
            return $fx($value);
        }, ['data' => new JsCallbackLoadableValue(null, function ($v) {
            $value = $this->getApp()->decodeJson($v);
            if (!$this->allowMultiple) {
                $value = $value[0];
            }

            return $value;
        })]);
    }

    #[\Override]
    protected function renderView(): void
    {
        parent::renderView();

        $this->itemSelector->template->tryDangerouslySetHtml('Input', $this->getInputTag());

        $this->itemSelector->vue('AtkTreeItemSelector', [
            'item' => ['id' => 'atk-root', 'nodes' => $this->treeItems],
            'values' => [], // need empty for Vue reactivity
            'field' => $this->shortName,
            'options' => [
                'mode' => $this->allowMultiple ? 'multiple' : 'single',
                'url' => $this->cb ? $this->cb->getJsUrl() : null,
                'loader' => $this->loaderCssName,
            ],
        ]);
    }
}
