<?php
namespace Zadex\ProContent;

defined('ABSPATH') || exit;

use Zadex\Documents\Document;
use Zadex\Frontend\Renderer;
use Zadex\Library\Store;
use Zadex\Theme\TemplatePost;

/**
 * Template widget (T192): renders a saved library template (`zadex_library`) or a theme template (`zadex_template`)
 * inside another document.
 *
 *  - Only published items on the site; the editor preview (POST /render) also shows drafts the user can edit.
 *  - Recursion guard: a template that (directly or through other template widgets) contains itself renders once,
 *    the nested occurrence is empty. The host document is on the stack too (`guard_host()`), so a page embedding a
 *    template that embeds that page does not loop.
 *  - The template's generated CSS (`_zadex_css` + page CSS) is queued once per request (\Zadex\Frontend\Styles).
 *  - In the editor canvas the inner markup loses its `data-zx-id` / `data-zx-type`, so selection, overlays and DnD
 *    never treat the template's nodes as elements of the edited document (same rule as TemplateRenderer).
 */
final class TemplateEmbed
{
    /** @var array<int, true> */
    private static array $stack = [];

    /** Test seam: reset the per-request state. */
    public static function reset(): void
    {
        self::$stack = [];
    }

    public static function is_embeddable(int $id): bool
    {
        if ($id <= 0 || !function_exists('get_post_type')) {
            return false;
        }
        $type = get_post_type($id);
        if ($type === Store::CPT) {
            return true;
        }
        // Theme templates: sections of the site (header, footer, loop items ...) are fine; a popup is not a section.
        return $type === TemplatePost::POST_TYPE && (string) get_post_meta($id, TemplatePost::META_TYPE, true) !== 'popup';
    }

    public static function can_view(int $id, bool $preview): bool
    {
        $post = get_post($id);
        if (!$post) {
            return false;
        }
        if (($post->post_status ?? '') === 'publish') {
            return true;
        }
        return $preview && current_user_can('edit_post', $id);
    }

    /**
     * HTML of the template's elements ('' when not embeddable, not visible or recursive). `$preview` = editor
     * preview (drafts allowed, element markers dropped).
     */
    public static function render(int $id, Renderer $renderer, bool $preview = false): string
    {
        if (!self::is_embeddable($id) || !self::can_view($id, $preview) || isset(self::$stack[$id])) {
            return '';
        }
        $host = function_exists('get_the_ID') ? (int) get_the_ID() : 0;
        if ($host === $id) {
            return '';
        }
        self::$stack[$id] = true;
        try {
            $data = Document::get_data($id);
            $html = $renderer->render_document(is_array($data['elements'] ?? null) ? $data['elements'] : []);
        } finally {
            unset(self::$stack[$id]);
        }
        if ($preview) {
            $html = (string) preg_replace('/\sdata-zx-(?:id|type)="[^"]*"/', '', $html);
        }
        \Zadex\Frontend\Styles::document($id);
        return $html;
    }

    /**
     * Option list for the widget's select: library templates first, then theme templates (not popups), drafts
     * marked. The document being edited is left out.
     *
     * @return array<int, array{value: string, label: string}>
     */
    public static function options(int $exclude = 0): array
    {
        $out = [['value' => '', 'label' => __('— Select —', 'zadex')]];
        if (!function_exists('get_posts')) {
            return $out;
        }
        $groups = [
            Store::CPT              => __('Library', 'zadex'),
            TemplatePost::POST_TYPE => __('Theme template', 'zadex'),
        ];
        foreach ($groups as $post_type => $group) {
            $posts = get_posts([
                'post_type'        => $post_type,
                'post_status'      => ['publish', 'draft', 'private'],
                'numberposts'      => 200,
                'orderby'          => 'title',
                'order'            => 'ASC',
            ]);
            foreach (is_array($posts) ? $posts : [] as $post) {
                $id = (int) $post->ID;
                if ($id === $exclude || !self::is_embeddable($id)) {
                    continue;
                }
                $title = (string) ($post->post_title ?? '');
                $label = $group . ': ' . ($title !== '' ? $title : '#' . $id);
                if (($post->post_status ?? '') !== 'publish') {
                    $label .= ' (' . __('draft', 'zadex') . ')';
                }
                $out[] = ['value' => (string) $id, 'label' => $label];
            }
        }
        return $out;
    }
}