<?php
namespace Zadex\Theme;

defined('ABSPATH') || exit;

use WP_Error;
use WP_REST_Request;
use WP_REST_Response;

/**
 * REST routes of the theme builder (namespace zadex/v1):
 *
 *   GET /templates/options?target=<target>&sub=<post type|taxonomy>&search=<text>
 *       -> { subs: Option[], values: Option[] }  options for the conditions dialog: the `sub` select of a target
 *          (post types / taxonomies) and its dependent value select (posts, terms, authors; searchable)
 *   GET /templates/{id}/conditions  -> { conditions, summary }
 *   PUT /templates/{id}/conditions  body { conditions: Rule[] } -> { conditions, summary }
 *
 * All routes require edit_theme_options.
 */
final class RestTemplates
{
    public const NS = 'zadex/v1';
    public const LIMIT = 20;

    public function register(): void
    {
        add_action('rest_api_init', [$this, 'routes']);
    }

    public function routes(): void
    {
        register_rest_route(self::NS, '/templates/options', [
            'methods'             => 'GET',
            'callback'            => [$this, 'options'],
            'permission_callback' => [$this, 'can_manage'],
        ]);
        register_rest_route(self::NS, '/templates/(?P<id>\d+)/conditions', [
            [
                'methods'             => 'GET',
                'callback'            => [$this, 'get_conditions'],
                'permission_callback' => [$this, 'can_manage'],
            ],
            [
                'methods'             => 'PUT, POST',
                'callback'            => [$this, 'save_conditions'],
                'permission_callback' => [$this, 'can_manage'],
            ],
        ]);
    }

    public function can_manage(): bool
    {
        return current_user_can(TemplatePost::CAPABILITY);
    }

    public function options(WP_REST_Request $request): WP_REST_Response
    {
        $target = sanitize_key((string) ($request['target'] ?? ''));
        $sub = sanitize_key((string) ($request['sub'] ?? ''));
        $search = sanitize_text_field((string) ($request['search'] ?? ''));
        return new WP_REST_Response(['subs' => self::subs($target), 'values' => self::values($target, $sub, $search)]);
    }

    /** Options of the `sub` select for a target. */
    public static function subs(string $target): array
    {
        if (in_array($target, ['post_type', 'singular', 'specific', 'archive'], true)) {
            $out = [];
            foreach (get_post_types(['public' => true], 'objects') as $name => $type) {
                if ($name === 'attachment' && $target !== 'singular' && $target !== 'specific') {
                    continue;
                }
                if ($target === 'archive' && $name !== 'post' && empty($type->has_archive)) {
                    continue;
                }
                $out[] = ['value' => (string) $name, 'label' => (string) $type->labels->name];
            }
            return $out;
        }
        if (in_array($target, ['taxonomy', 'term'], true)) {
            $out = [];
            foreach (get_taxonomies(['public' => true], 'objects') as $name => $tax) {
                if ($name === 'post_format') {
                    continue;
                }
                $out[] = ['value' => (string) $name, 'label' => (string) $tax->labels->name];
            }
            return $out;
        }
        return [];
    }

    /** Options of the value select (posts of a type, terms of a taxonomy, authors). */
    public static function values(string $target, string $sub, string $search = ''): array
    {
        $out = [];
        if ($target === 'specific' && $sub !== '' && post_type_exists($sub)) {
            $posts = get_posts([
                'post_type'        => $sub,
                'post_status'      => ['publish', 'private', 'draft', 'future'],
                'numberposts'      => self::LIMIT,
                's'                => $search,
                'orderby'          => $search !== '' ? 'relevance' : 'date',
                'order'            => 'DESC',
            ]);
            foreach ($posts as $post) {
                $out[] = ['value' => (int) $post->ID, 'label' => ($post->post_title !== '' ? $post->post_title : __('(no title)', 'zadex')) . ' (#' . (int) $post->ID . ')'];
            }
        } elseif ($target === 'term' && $sub !== '' && taxonomy_exists($sub)) {
            $terms = get_terms(['taxonomy' => $sub, 'hide_empty' => false, 'number' => self::LIMIT, 'search' => $search]);
            if (is_array($terms)) {
                foreach ($terms as $term) {
                    $out[] = ['value' => (int) $term->term_id, 'label' => (string) $term->name];
                }
            }
        } elseif ($target === 'author') {
            $users = get_users(['number' => self::LIMIT, 'search' => $search !== '' ? '*' . $search . '*' : '', 'fields' => ['ID', 'display_name'], 'capability' => ['edit_posts']]);
            foreach ($users as $user) {
                $out[] = ['value' => (int) $user->ID, 'label' => (string) $user->display_name];
            }
        } elseif (!in_array($target, Conditions::TARGETS, true)) {
            // Targets added by integrations (WooCommerce: products, product categories / tags).
            $extra = apply_filters('zadex/theme/condition_values', [], $target, $sub, $search);
            $out = is_array($extra) ? array_values($extra) : [];
        }
        return $out;
    }

    public function get_conditions(WP_REST_Request $request)
    {
        $id = (int) $request['id'];
        if (!TemplatePost::is_template($id)) {
            return new WP_Error('zadex_not_template', __('Not a theme template.', 'zadex'), ['status' => 404]);
        }
        $rules = TemplatePost::conditions($id);
        return new WP_REST_Response(['conditions' => $rules, 'summary' => Conditions::summary($rules)]);
    }

    public function save_conditions(WP_REST_Request $request)
    {
        $id = (int) $request['id'];
        if (!TemplatePost::is_template($id)) {
            return new WP_Error('zadex_not_template', __('Not a theme template.', 'zadex'), ['status' => 404]);
        }
        $body = $request->get_json_params();
        if (!is_array($body) || !isset($body['conditions']) || !is_array($body['conditions'])) {
            return new WP_Error('zadex_bad_request', __('Missing conditions.', 'zadex'), ['status' => 400]);
        }
        $rules = TemplatePost::set_conditions($id, $body['conditions']);
        Resolver::reset();
        return new WP_REST_Response(['conditions' => $rules, 'summary' => Conditions::summary($rules)]);
    }
}