<?php
namespace Zadex\Dynamic;

defined('ABSPATH') || exit;

use WP_Error;
use WP_REST_Request;
use WP_REST_Response;

/**
 * REST routes for the editor (namespace zadex/v1, capability `edit_posts`):
 *
 *  POST /dynamic/resolve  { postId, items: [{ id, value: {__dynamic}, type }] } -> { values: { id: resolved } }
 *  GET  /dynamic/options  ?tag=custom-field&control=key&search=&postId=      -> { options: [{value,label}] }
 *
 * The context post is only used when the user may edit it; otherwise tags render without a post (fallbacks).
 */
final class DynamicController
{
    public const NS = 'zadex/v1';
    public const MAX_ITEMS = 200;

    private ?Registry $registry;

    public function __construct(?Registry $registry = null)
    {
        $this->registry = $registry;
    }

    public function register(): void
    {
        add_action('rest_api_init', [$this, 'routes']);
    }

    public function routes(): void
    {
        register_rest_route(self::NS, '/dynamic/resolve', [
            'methods'             => 'POST',
            'callback'            => [$this, 'resolve'],
            'permission_callback' => [$this, 'can_use'],
        ]);
        register_rest_route(self::NS, '/dynamic/options', [
            'methods'             => 'GET',
            'callback'            => [$this, 'options'],
            'permission_callback' => [$this, 'can_use'],
        ]);
    }

    public function can_use(): bool
    {
        return current_user_can('edit_posts');
    }

    /** @return WP_REST_Response|WP_Error */
    public function resolve(WP_REST_Request $request)
    {
        $body = $request->get_json_params();
        if (!is_array($body) || !isset($body['items']) || !is_array($body['items'])) {
            return new WP_Error('zadex_bad_request', __('Missing items.', 'zadex'), ['status' => 400]);
        }
        $ctx = $this->context((int) ($body['postId'] ?? 0));
        $registry = $this->registry();
        $values = [];
        foreach (array_slice($body['items'], 0, self::MAX_ITEMS) as $item) {
            if (!is_array($item) || !isset($item['id']) || !is_scalar($item['id']) || !Value::is($item['value'] ?? null)) {
                continue;
            }
            $type = isset($item['type']) && is_string($item['type']) && Value::category_for_control($item['type']) !== null ? $item['type'] : 'text';
            $values[(string) $item['id']] = Resolver::resolve($item['value'], $ctx, $type, $registry);
        }
        return new WP_REST_Response(['values' => (object) $values]);
    }

    /** @return WP_REST_Response|WP_Error */
    public function options(WP_REST_Request $request)
    {
        $name = is_string($request['tag']) ? sanitize_key($request['tag']) : '';
        $tag = $this->registry()->get($name);
        if (!$tag) {
            return new WP_Error('zadex_unknown_tag', __('Unknown dynamic tag.', 'zadex'), ['status' => 404]);
        }
        $control = is_string($request['control']) ? sanitize_key($request['control']) : '';
        $search = is_string($request['search']) ? sanitize_text_field($request['search']) : '';
        $ctx = $this->context((int) ($request['postId'] ?? 0));
        $options = [];
        foreach ($tag->options($control, $search, $ctx) as $opt) {
            if (is_array($opt) && isset($opt['value']) && is_scalar($opt['value'])) {
                $options[] = ['value' => (string) $opt['value'], 'label' => (string) ($opt['label'] ?? $opt['value'])];
            }
        }
        return new WP_REST_Response(['options' => $options]);
    }

    private function context(int $post_id): Context
    {
        if ($post_id > 0 && current_user_can('edit_post', $post_id)) {
            return Context::for_post($post_id);
        }
        return Context::for_post(0);
    }

    private function registry(): Registry
    {
        return $this->registry ?? Registry::instance();
    }
}