<?php
// SPDX-License-Identifier: GPL-3.0-or-later
declare(strict_types=1);

namespace Aiwend\WordPress;

/**
 * Lifetime of AI Forms submissions: every row carries its own expiry (default 30 days, 1 to 365, set by the administrator). Rows are ignored once
 * expired, removed by the daily core job (also when the module is off), by the administrator, through the WordPress personal-data tools and, for
 * a deleted site or an opt-in uninstall, with the site's tables. The sweep deletes oldest expiry first in bounded batches, so a pile of valid rows
 * can never hide expired ones, and repeating it is harmless. Lowering the retention period shortens the expiry of stored rows too; raising it does
 * not extend rows already stored.
 */
final class AiFormsRetention
{
    public const SWEEP_BATCH = 200;
    public const SWEEP_BATCHES = 5;
    public const EXPORT_PAGE = 50;

    public static function register(Plugin $plugin): void
    {
        add_filter('wp_privacy_personal_data_exporters', static function (array $exporters) use ($plugin): array {
            $exporters['aiwend-forms'] = ['exporter_friendly_name' => __('Aiwend AI Forms', 'aiwend'), 'callback' => static fn(string $email, int $page = 1): array => self::export($plugin, $email, $page)];
            return $exporters;
        });
        add_filter('wp_privacy_personal_data_erasers', static function (array $erasers) use ($plugin): array {
            $erasers['aiwend-forms'] = ['eraser_friendly_name' => __('Aiwend AI Forms', 'aiwend'), 'callback' => static fn(string $email, int $page = 1): array => self::erase($plugin, $email, $page)];
            return $erasers;
        });
    }

    /** Daily sweep for the current site. Returns the number of rows removed. */
    public static function sweep(Plugin $plugin, int $now, int $batch = self::SWEEP_BATCH, int $batches = self::SWEEP_BATCHES): int
    {
        $store = AiFormsConfig::store($plugin);
        $site = get_current_blog_id();
        $removed = 0;
        for ($i = 0; $i < $batches; $i++) {
            $n = $store->expire($site, $now, $batch);
            $removed += $n;
            if ($n < $batch) {
                break;
            }
        }
        return $removed;
    }

    /**
     * WordPress calls this only for a personal-data request whose email address the requester has confirmed (the core request flow), and
     * only for the CURRENT site, so a record of another site or of an unverified address is never returned.
     *
     * @return array{data: list<array<string, mixed>>, done: bool}
     */
    public static function export(Plugin $plugin, string $email, int $page = 1): array
    {
        $site = get_current_blog_id();
        $store = AiFormsConfig::store($plugin);
        $rows = $store->byEmail($site, $email, (max(1, $page) - 1) * self::EXPORT_PAGE, self::EXPORT_PAGE);
        $data = [];
        foreach ($rows as $r) {
            $items = [
                ['name' => __('Form', 'aiwend'), 'value' => (string) (AiFormsConfig::forms()[(int) $r['form_id']]['title'] ?? ('#' . (int) $r['form_id']))],
                ['name' => __('Submitted', 'aiwend'), 'value' => gmdate('Y-m-d H:i:s', (int) $r['created_at']) . ' UTC'],
                ['name' => __('Name', 'aiwend'), 'value' => (string) $r['name']],
                ['name' => __('Email', 'aiwend'), 'value' => (string) $r['email']],
                ['name' => __('Topic', 'aiwend'), 'value' => (string) $r['topic']],
                ['name' => __('Message', 'aiwend'), 'value' => (string) $r['message']],
                ['name' => __('Expires', 'aiwend'), 'value' => gmdate('Y-m-d H:i:s', (int) $r['expires_at']) . ' UTC'],
            ];
            if ((string) $r['analysis_state'] === 'done') {
                $items[] = ['name' => __('AI summary (administrator analysis)', 'aiwend'), 'value' => (string) $r['summary']];
                $items[] = ['name' => __('AI category', 'aiwend'), 'value' => (string) $r['category']];
                $items[] = ['name' => __('AI reply draft', 'aiwend'), 'value' => (string) $r['reply']];
            }
            $data[] = ['group_id' => 'aiwend-forms', 'group_label' => __('Contact form submissions', 'aiwend'), 'item_id' => 'aiwend-form-' . $site . '-' . (int) $r['id'], 'data' => $items];
        }
        return ['data' => $data, 'done' => count($rows) < self::EXPORT_PAGE];
    }

    /** @return array{items_removed: bool, items_retained: bool, messages: list<string>, done: bool} */
    public static function erase(Plugin $plugin, string $email, int $page = 1): array
    {
        $site = get_current_blog_id();
        $store = AiFormsConfig::store($plugin);
        $removed = $store->eraseEmail($site, $email, 200);
        $more = $store->countForEmail($site, $email) > 0;
        return [
            'items_removed' => $removed > 0,
            'items_retained' => false,
            'messages' => $removed > 0 ? [__('Contact form submissions on this site, including any AI summary or reply draft stored with them, were deleted. If an administrator had the text analysed, the AI provider may still hold its own copy under its own terms; deleting it here does not delete that copy, and backups of this site are not rewritten.', 'aiwend')] : [],
            'done' => !$more,
        ];
    }
}