<?php

declare(strict_types=1);

namespace Sarcio\WordPress\Assistant;

use Sarcio\WordPress\Account;
use Sarcio\WordPress\Admin\RequestsPage;
use Sarcio\WordPress\Options;

/**
 * Across sites: a change an agency wrote once in Sarcio for several sites.
 * Every few minutes this site asks for its next task with its own key and
 * prepares it here as a preview, through Remote's list of what an agency may
 * touch, then leaves it under Sarcio → Requests. Nothing is applied from
 * here: an administrator reviews the preview and presses Apply, as
 * themselves. An undo the agency asks for waits there the same way.
 */
final class Bulk
{
    public const HOOK = 'sarcio_bulk_poll';
    public const SCHEDULE = 'sarcio_five_minutes';
    private const MAX_TURNS = 12;
    private const MAX_CALLS = 60;

    public function register(): void
    {
        add_filter('cron_schedules', [$this, 'schedules']);
        add_action(self::HOOK, [self::class, 'poll']);
        add_action('init', [self::class, 'reconcileSchedule'], 20);
    }

    public static function reconcileSchedule(): void
    {
        if (!self::enabled()) {
            if (wp_next_scheduled(self::HOOK)) {
                self::unschedule();
            }
            return;
        }
        if (!wp_next_scheduled(self::HOOK)) {
            wp_schedule_event(time() + 120, self::SCHEDULE, self::HOOK);
        }
    }

    /** Only once an administrator turns it on, and only on a connected site. */
    public static function enabled(): bool
    {
        return (bool) Options::get('bulk_enabled') && (string) Options::get('site_key') !== '' && (string) Options::get('sidecar_key') !== '';
    }

    /** @param array<string,array<string,mixed>> $schedules */
    public function schedules(array $schedules): array
    {
        $schedules[self::SCHEDULE] = ['display' => __('Every five minutes (Sarcio)', 'sarcio'), 'interval' => 300];
        return $schedules;
    }

    public static function unschedule(): void
    {
        $next = wp_next_scheduled(self::HOOK);
        if ($next) {
            wp_unschedule_event($next, self::HOOK);
        }
    }

    /** The administrator the site runs an ask as: one with a stored Sarcio sign-in. */
    public static function runner(): int
    {
        $preferred = (int) Options::get('bulk_user');
        if ($preferred > 0 && Account::has($preferred) && user_can($preferred, 'manage_options')) {
            return $preferred;
        }
        foreach (get_users(['role' => 'administrator', 'fields' => 'ID', 'number' => 50]) as $id) {
            if (Account::has((int) $id)) {
                return (int) $id;
            }
        }
        return 0;
    }

    /** WP-Cron: one task per poll. */
    public static function poll(): void
    {
        if (!self::enabled()) {
            return;
        }
        $task = self::fetch();
        if ($task === null) {
            return;
        }
        $runner = self::runner();
        if ($runner === 0) {
            self::report((string) $task['id'], ['error' => __('No administrator on this site has connected their Sarcio account, so nothing can run here.', 'sarcio'), 'status' => 'FAILED', 'summary' => []]);
            return;
        }
        $previous = get_current_user_id();
        wp_set_current_user($runner);
        Remote::begin();
        try {
            $result = ($task['kind'] ?? 'ASK') === 'UNDO' ? self::undo((array) ($task['changeIds'] ?? [])) : self::run((string) ($task['text'] ?? ''));
        } catch (\Throwable $e) {
            $result = ['error' => sanitize_text_field($e->getMessage()), 'status' => 'FAILED', 'summary' => []];
        } finally {
            Remote::end();
            wp_set_current_user($previous);
        }
        self::report((string) $task['id'], $result);
    }

    /**
     * The assistant loop without a browser, preparing only: reads from the
     * allowed list run, allowed changes are laid over a preview, and the
     * preview becomes a request for an administrator.
     *
     * @return array{status:string,summary:array<int,string>,error?:string,adminUrl?:string,requestId?:string}
     */
    public static function run(string $text): array
    {
        if (!Remote::active()) {
            return ['error' => __('Changes written for several sites are only prepared by the scheduled check.', 'sarcio'), 'status' => 'FAILED', 'summary' => []];
        }
        Catalog::reset();
        $stage = Stage::sync('', []);
        if (!$stage['ok']) {
            return ['error' => (string) ($stage['error'] ?? ''), 'status' => 'FAILED', 'summary' => []];
        }
        $messages = [['role' => 'user', 'text' => $text]];
        $summaries = [];
        $previews = [];
        $calls = 0;
        $lastText = '';
        for ($turn = 0; $turn < self::MAX_TURNS; $turn++) {
            $reply = Client::turn(get_current_user_id(), $messages, '', Remote::catalog());
            if (isset($reply['error']) || isset($reply['reconnect'])) {
                Stage::clear((string) $stage['token']);
                return ['error' => (string) ($reply['error'] ?? __('The site’s Sarcio sign-in needs renewing.', 'sarcio')), 'status' => 'FAILED', 'summary' => array_values($summaries)];
            }
            $lastText = (string) ($reply['text'] ?? '');
            $messages[] = ['calls' => $reply['calls'], 'role' => 'assistant', 'text' => $lastText];
            if ($reply['calls'] === []) {
                break;
            }
            $results = [];
            foreach ($reply['calls'] as $call) {
                $id = (string) $call['id'];
                $args = is_array($call['args']) ? $call['args'] : [];
                if (++$calls > self::MAX_CALLS) {
                    $results[] = ['id' => $id, 'ok' => false, 'skipped' => true, 'error' => __('Too many steps for one ask.', 'sarcio')];
                    continue;
                }
                $ability = Remote::allows((string) $call['ability']) ? Catalog::get((string) $call['ability']) : null;
                if ($ability === null) {
                    $results[] = ['id' => $id, 'ok' => false, 'error' => __('Not something this site can do.', 'sarcio')];
                    continue;
                }
                if ($ability->kind === Ability::READ) {
                    $one = Catalog::run($ability->name, $args);
                    $results[] = ['id' => $id, 'ok' => (bool) $one['ok'], 'output' => $one['ok'] ? Transcript::capOutput($one['output'] ?? []) : null] + ($one['ok'] ? [] : ['error' => (string) ($one['error'] ?? '')]);
                    continue;
                }
                if ($ability->stage !== null) {
                    $staged = Stage::add($id, $ability->name, $args);
                    if ($staged['ok']) {
                        $summaries[$id] = (string) ($staged['summary'] ?? Catalog::label($ability->name));
                        $previews[$id] = ['after' => (string) ($staged['after'] ?? ''), 'before' => (string) ($staged['before'] ?? ''), 'summary' => $summaries[$id]];
                    }
                    $results[] = ['id' => $id, 'ok' => (bool) $staged['ok'], 'output' => $staged['ok'] ? ['staged' => true, 'summary' => $summaries[$id]] : null] + ($staged['ok'] ? [] : ['error' => (string) ($staged['error'] ?? '')]);
                    continue;
                }
                $results[] = ['id' => $id, 'ok' => false, 'skipped' => true, 'error' => __('This cannot be previewed, so it was left out. Someone on the site can ask for it in the assistant.', 'sarcio')];
            }
            $messages[] = ['results' => $results, 'role' => 'result'];
        }
        $lines = array_values(array_map(static fn (string $line): string => mb_substr($line, 0, 300), $summaries));
        if (Stage::changes() === []) {
            Stage::clear((string) $stage['token']);
            return ['error' => $lastText !== '' ? mb_substr($lastText, 0, 1000) : __('The assistant found nothing to change.', 'sarcio'), 'status' => 'FAILED', 'summary' => $lines];
        }
        $request = Requests::fromStage(mb_substr($text, 0, 200), $previews, Requests::ORIGIN_AGENCY);
        if (!$request['ok']) {
            Stage::clear((string) $stage['token']);
            return ['error' => (string) ($request['error'] ?? ''), 'status' => 'FAILED', 'summary' => $lines];
        }
        return ['adminUrl' => RequestsPage::url((string) $request['request']['id']), 'requestId' => (string) $request['request']['id'], 'status' => 'STAGED', 'summary' => $lines];
    }

    /** @param array<int,mixed> $changeIds */
    public static function undo(array $changeIds): array
    {
        if (!Remote::active()) {
            return ['error' => __('Changes written for several sites are only prepared by the scheduled check.', 'sarcio'), 'status' => 'FAILED', 'summary' => []];
        }
        $request = Requests::fromAgencyUndo(array_values(array_filter(array_map('intval', $changeIds))));
        if (!$request['ok']) {
            return ['error' => (string) ($request['error'] ?? ''), 'status' => 'FAILED', 'summary' => []];
        }
        $lines = array_values(array_map(static fn (array $change): string => (string) $change['summary'], $request['request']['changes'] ?? []));
        return ['adminUrl' => RequestsPage::url((string) $request['request']['id']), 'requestId' => (string) $request['request']['id'], 'status' => 'STAGED', 'summary' => $lines];
    }

    /** @return array<string,mixed>|null */
    private static function fetch(): ?array
    {
        $siteKey = (string) Options::get('site_key');
        $secret = (string) Options::get('sidecar_key');
        if ($siteKey === '' || $secret === '') {
            return null;
        }
        $response = wp_remote_get(
            sprintf('%s/api/sites/%s/bulk-asks/pending', Options::apiUrl(), rawurlencode($siteKey)),
            ['headers' => ['Authorization' => 'Bearer ' . $secret], 'redirection' => 0, 'timeout' => 8],
        );
        if (is_wp_error($response) || (int) wp_remote_retrieve_response_code($response) !== 200) {
            return null;
        }
        $body = json_decode((string) wp_remote_retrieve_body($response), true);
        $task = is_array($body) && is_array($body['task'] ?? null) ? $body['task'] : null;
        return $task !== null && is_string($task['id'] ?? null) && preg_match('~^[A-Za-z0-9-]{1,64}$~', $task['id']) ? $task : null;
    }

    /** @param array<string,mixed> $result */
    private static function report(string $taskId, array $result): void
    {
        $siteKey = (string) Options::get('site_key');
        $secret = (string) Options::get('sidecar_key');
        if ($siteKey === '' || $secret === '') {
            return;
        }
        wp_remote_post(
            sprintf('%s/api/sites/%s/bulk-asks/%s/result', Options::apiUrl(), rawurlencode($siteKey), rawurlencode($taskId)),
            [
                'body' => (string) wp_json_encode(array_filter([
                    'adminUrl' => $result['adminUrl'] ?? null,
                    'changeIds' => $result['changeIds'] ?? null,
                    'error' => isset($result['error']) && $result['error'] !== '' ? mb_substr((string) $result['error'], 0, 1000) : null,
                    'requestId' => $result['requestId'] ?? null,
                    'status' => (string) $result['status'],
                    'summary' => array_slice((array) ($result['summary'] ?? []), 0, 100),
                ], static fn ($value): bool => $value !== null)),
                'headers' => ['Authorization' => 'Bearer ' . $secret, 'Content-Type' => 'application/json'],
                'redirection' => 0,
                'timeout' => 8,
            ],
        );
    }
}