<?php
namespace Zadex\Library;

defined('ABSPATH') || exit;

use WP_Error;
use Zadex\Documents\Document;
use Zadex\Documents\Sanitizer;
use Zadex\Widgets\WidgetRegistry;

/**
 * Saved templates ("My templates") live in the private post type `zadex_library` (never public, no admin UI).
 *
 * Meta keys:
 *  _zadex_library_type   'section' | 'page'
 *  _zadex_library_tags   string[]
 *  _zadex_data           JSON {version, elements} (same format and helpers as a page, see Document)
 *  _zadex_css            CSS generated by the editor when the template was saved (informational)
 *  _zadex_page_settings  page settings of a page template (page templates only)
 *
 * The optional featured image is the card thumbnail.
 */
final class Store
{
    public const CPT = 'zadex_library';
    public const META_TYPE = '_zadex_library_type';
    public const META_TAGS = '_zadex_library_tags';
    public const TYPES = ['section', 'page'];
    public const MAX_TAGS = 12;

    private WidgetRegistry $widgets;

    public function __construct(WidgetRegistry $widgets)
    {
        $this->widgets = $widgets;
    }

    public static function register_post_type(): void
    {
        register_post_type(self::CPT, [
            'label'               => __('Zadex templates', 'zadex'),
            'public'              => false,
            'publicly_queryable'  => false,
            'exclude_from_search' => true,
            'show_ui'             => false,
            'show_in_menu'        => false,
            'show_in_nav_menus'   => false,
            'show_in_rest'        => false,
            'rewrite'             => false,
            'query_var'           => false,
            'has_archive'         => false,
            'hierarchical'        => false,
            'supports'            => ['title', 'thumbnail', 'author'],
            'capability_type'     => 'post',
            'map_meta_cap'        => true,
        ]);
    }

    public static function sanitize_type($value): string
    {
        return is_string($value) && in_array($value, self::TYPES, true) ? $value : 'section';
    }

    /** @return string[] lower-case, trimmed, unique, at most MAX_TAGS. */
    public static function sanitize_tags($value): array
    {
        if (is_string($value)) {
            $value = explode(',', $value);
        }
        if (!is_array($value)) {
            return [];
        }
        $out = [];
        foreach ($value as $tag) {
            if (!is_scalar($tag)) {
                continue;
            }
            $tag = strtolower(trim(sanitize_text_field((string) $tag)));
            if ($tag !== '' && mb_strlen($tag) <= 40 && !in_array($tag, $out, true)) {
                $out[] = $tag;
            }
        }
        return array_slice($out, 0, self::MAX_TAGS);
    }

    /**
     * Creates a template. Elements are sanitized through the widget manifests.
     *
     * @return int|WP_Error new post id
     */
    public function create(string $title, string $type, array $elements, string $css = '', ?array $page_settings = null, array $tags = [])
    {
        $title = trim(sanitize_text_field($title));
        if ($title === '') {
            return new WP_Error('zadex_bad_request', __('A template needs a name.', 'zadex'), ['status' => 400]);
        }
        $sanitizer = new Sanitizer($this->widgets);
        $clean = $sanitizer->sanitize_elements($elements);
        if (!$clean) {
            return new WP_Error('zadex_bad_request', __('The template has no valid elements.', 'zadex'), ['status' => 400]);
        }
        $id = wp_insert_post(wp_slash([
            'post_type'    => self::CPT,
            'post_title'   => $title,
            'post_status'  => 'publish',
            'post_content' => '',
        ]), true);
        if (is_wp_error($id)) {
            return $id;
        }
        $id = (int) $id;
        $type = self::sanitize_type($type);
        update_post_meta($id, self::META_TYPE, $type);
        update_post_meta($id, self::META_TAGS, self::sanitize_tags($tags));
        update_post_meta($id, Document::META_DATA, wp_slash(wp_json_encode(['version' => Document::VERSION, 'elements' => $clean], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES)));
        update_post_meta($id, Document::META_CSS, wp_slash(Document::sanitize_css($css)));
        if ($type === 'page' && $page_settings !== null) {
            update_post_meta($id, Document::META_PAGE, wp_slash(wp_json_encode($sanitizer->sanitize_settings_generic($page_settings), JSON_UNESCAPED_UNICODE)));
        }
        do_action('zadex/library/saved', $id, $type);
        return $id;
    }

    /** True when $id is a library item. */
    public function exists(int $id): bool
    {
        $post = $id > 0 ? get_post($id) : null;
        return $post !== null && (string) ($post->post_type ?? '') === self::CPT && (string) ($post->post_status ?? '') !== 'trash';
    }

    /** @return array<int, array<string, mixed>> summaries, newest first */
    public function all(string $type = ''): array
    {
        $args = [
            'post_type'      => self::CPT,
            'post_status'    => 'publish',
            'posts_per_page' => 200,
            'orderby'        => 'date',
            'order'          => 'DESC',
            'no_found_rows'  => true,
        ];
        if (in_array($type, self::TYPES, true)) {
            // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- library items are filtered by their type meta.
            $args['meta_query'] = [['key' => self::META_TYPE, 'value' => $type]];
        }
        $out = [];
        foreach (get_posts($args) as $post) {
            $item = $this->summary($post);
            if ($type === '' || $item['type'] === $type) {
                $out[] = $item;
            }
        }
        return $out;
    }

    /** @return array<string, mixed> */
    public function summary($post): array
    {
        $id = (int) $post->ID;
        $tags = get_post_meta($id, self::META_TAGS, true);
        $thumb = function_exists('get_the_post_thumbnail_url') ? get_the_post_thumbnail_url($id, 'medium') : '';
        $author = function_exists('get_userdata') ? get_userdata((int) ($post->post_author ?? 0)) : null;
        return [
            'id'        => $id,
            'title'     => (string) $post->post_title,
            'type'      => self::sanitize_type(get_post_meta($id, self::META_TYPE, true)),
            'tags'      => self::sanitize_tags(is_array($tags) ? $tags : []),
            'thumbnail' => is_string($thumb) ? $thumb : '',
            'date'      => (string) ($post->post_date_gmt ?? $post->post_modified_gmt ?? ''),
            'author'    => $author ? (string) $author->display_name : '',
        ];
    }

    /** Full template: summary + elements (+ page settings for page templates). */
    public function get(int $id): ?array
    {
        if (!$this->exists($id)) {
            return null;
        }
        $post = get_post($id);
        $data = Document::get_data($id);
        $item = $this->summary($post);
        $item['elements'] = $data['elements'];
        $item['css'] = Document::get_css($id);
        $page = Document::get_page_settings($id);
        $item['pageSettings'] = $page ? $page : (object) [];
        return $item;
    }

    public function delete(int $id): bool
    {
        if (!$this->exists($id)) {
            return false;
        }
        return (bool) wp_delete_post($id, true);
    }
}