<?php

if (!defined('ABSPATH')) {
    exit;
}

if (!class_exists('Baton_AI')) {

    // turns raw recorded clicks into dead-simple step descriptions
    class Baton_AI
    {
        // the baton-ai Worker (see worker/)
        const ENDPOINT = 'https://baton-ai.chidideveloper.workers.dev/v1/steps';

        const TIMEOUT = 20;


        /**
         * Asks the Worker to describe each step. Only labels, tags and page titles are sent.
         *
         * @return string[]|WP_Error one description per step, same order
         */
        public static function describe(array $steps)
        {
            if (!$steps) {
                return [];
            }

            $response = wp_remote_post(apply_filters('baton_ai_endpoint', self::ENDPOINT), [
                'timeout' => self::TIMEOUT,
                /**
                 * Headers sent to the AI service, for add-ons with their own service plan.
                 *
                 * @param array $headers
                 */
                'headers' => apply_filters('baton_ai_headers', [
                    'content-type' => 'application/json',
                    // counts this site's daily allowance; a one-way hash, so the service never learns the address
                    'x-baton-site' => self::siteId(),
                ]),
                'body' => wp_json_encode([
                    'steps' => array_map(fn(array $step) => [
                        // the menu place in the dashboard, else the page's own name
                        'page'  => ($step['place'] ?? '') !== '' ? $step['place'] : Baton_Admin::pageName($step),
                        'tag'   => $step['tag'] ?? '',
                        'kind'  => $step['kind'] ?? Baton_Walkthroughs::guessKind((string) ($step['tag'] ?? '')),
                        'label' => $step['label'] ?? '',
                    ], array_values($steps)),
                ]),
            ]);

            if (is_wp_error($response)) {
                return new WP_Error('baton_ai_unreachable', __('The AI service could not be reached.', 'baton'));
            }

            $code = (int) wp_remote_retrieve_response_code($response);

            $body = json_decode(wp_remote_retrieve_body($response), true);

            if ($code === 429 && ($body['error'] ?? '') === 'daily_limit') {
                return new WP_Error('baton_ai_daily_limit', sprintf(
                    /* translators: %d: AI rewrites allowed per day */
                    __('You’ve used today’s %d AI rewrites. More tomorrow, or unlimited with Baton Pro.', 'baton'),
                    (int) ($body['limit'] ?? 10)
                ));
            }

            if ($code === 429) {
                return new WP_Error('baton_ai_busy', __('The AI service is busy. Try again in a minute.', 'baton'));
            }

            $texts = $body['steps'] ?? null;

            if ($code !== 200 || !is_array($texts) || count($texts) !== count($steps)) {
                return new WP_Error('baton_ai_bad_response', __('The AI service sent back something unexpected.', 'baton'));
            }

            return array_map(
                fn($text) => is_string($text) ? mb_substr(sanitize_text_field($text), 0, 200) : '',
                array_values($texts)
            );
        }

        public static function siteId(): string
        {
            return hash('sha256', untrailingslashit(home_url()));
        }

        /**
         * Rewrites every step's text with AI, keeping the old text for any the AI left blank.
         *
         * @return array|WP_Error the steps with new text
         */
        public static function rewrite(array $steps)
        {
            $texts = self::describe($steps);

            if (is_wp_error($texts)) {
                return $texts;
            }

            foreach (array_values($texts) as $i => $text) {
                if ($text !== '') {
                    $steps[$i]['text'] = $text;
                }
            }

            return $steps;
        }
    }
}