<?php

declare(strict_types=1);

namespace AetosSeo\Utils;

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

use AetosSeo\Core\Settings;

/**
 * v3.0.0 — Locale-aware text helper.
 *
 * Replaces the per-page private `t()` helpers (LicensePage had its own;
 * everywhere else mixed Arabic + English in single strings or fell back
 * to English-only). Single source of truth for "show Arabic or English"
 * decisions across admin pages, menus, JS i18n payloads, and emails.
 *
 *   I18n::tr('Dashboard', 'لوحة التحكم')   → 'لوحة التحكم' on Arabic locale
 *   I18n::is_arabic()                       → bool
 *
 * Locale source:
 *   1. Plugin Settings → ui.admin_locale: 'ar' / 'en' / 'auto' (default 'auto')
 *   2. If 'auto': WP `is_rtl()` (true → Arabic) or `get_locale()` starts-with 'ar'
 *
 * Filterable: `apply_filters('aetos_seo_admin_locale', 'ar'|'en')`.
 */
class I18n
{
    /** @var string|null lazy cache, reset() to clear */
    private static $cached_lang = null;

    /**
     * Return Arabic or English text based on the current admin locale.
     */
    public static function tr(string $en, string $ar): string
    {
        return self::is_arabic() ? $ar : $en;
    }

    /**
     * 4.0.18: a counted noun phrase that agrees with its number in both
     * languages. Every form may contain %d for the number.
     *
     * English: $en_one for 1, $en_many otherwise.
     * Arabic:  $ar_one for 1 ("صفحة واحدة"), $ar_two for 2 ("صفحتان"),
     *          $ar_few when the last two digits are 3 to 10 ("%d صفحات"),
     *          $ar_many for 11 to 99 ("%d صفحة", "%d رابطًا"), and for
     *          0, 100, 101 and so on the singular without the accusative
     *          ending ("100 رابط").
     */
    public static function n(int $n, string $en_one, string $en_many, string $ar_one, string $ar_two, string $ar_few, string $ar_many): string
    {
        if (!self::is_arabic()) {
            return sprintf($n === 1 ? $en_one : $en_many, $n);
        }
        if ($n === 1) {
            return sprintf($ar_one, $n);
        }
        if ($n === 2) {
            return sprintf($ar_two, $n);
        }
        $tail = abs($n) % 100;
        if ($tail >= 3 && $tail <= 10) {
            return sprintf($ar_few, $n);
        }
        if ($tail >= 11) {
            return sprintf($ar_many, $n);
        }
        // 0, 100, 101, 102, 200 ...: genitive singular (drop the accusative alif tanween).
        return sprintf(str_replace(["\u{064B}\u{0627}", "\u{0627}\u{064B}"], '', $ar_many), $n);
    }

    public static function is_arabic(): bool
    {
        return self::lang() === 'ar';
    }

    public static function contains_arabic(string $text): bool
    {
        return preg_match('/[\x{0600}-\x{06FF}]/u', $text) === 1;
    }

    public static function english_safe(string $text, string $fallback = ''): string
    {
        $text = trim($text);
        if ($text === '') {
            return $fallback;
        }
        if (!self::is_arabic() && self::contains_arabic($text)) {
            return $fallback;
        }
        return $text;
    }

    /**
     * 4.0.18: run $fn with I18n::tr() resolving to $lang, then restore the
     * previous language. The audit uses this to render every finding in both
     * shipped languages during one scan, so switching the admin language later
     * shows the finding in the new language instead of the scan's language.
     *
     * @template T
     * @param callable():T $fn
     * @return T
     */
    public static function with_lang(string $lang, callable $fn)
    {
        $lang = in_array($lang, ['ar', 'en'], true) ? $lang : 'en';
        $previous = self::$cached_lang;
        self::$cached_lang = $lang;
        try {
            return $fn();
        } finally {
            self::$cached_lang = $previous;
        }
    }

    /**
     * The shipped language other than $lang.
     */
    public static function other_lang(string $lang): string
    {
        return $lang === 'ar' ? 'en' : 'ar';
    }

    public static function lang(): string
    {
        if (self::$cached_lang !== null) {
            return self::$cached_lang;
        }
        $lang = self::resolve_lang();
        if (function_exists('apply_filters')) {
            $lang = (string) apply_filters('aetos_seo_admin_locale', $lang);
        }
        if (!in_array($lang, ['ar', 'en'], true)) {
            $lang = 'en';
        }
        self::$cached_lang = $lang;
        return $lang;
    }

    private static function resolve_lang(): string
    {
        // 1. Plugin Settings override.
        if (class_exists(Settings::class)) {
            try {
                $s = Settings::get();
                $ui = isset($s['ui']) && is_array($s['ui']) ? $s['ui'] : [];
                $admin_locale = isset($ui['admin_locale']) ? strtolower((string) $ui['admin_locale']) : 'auto';
                if ($admin_locale === 'ar' || $admin_locale === 'en') {
                    return $admin_locale;
                }
            } catch (\Throwable $e) {
                // Fall through.
            }
        }
        // 2. Auto: derive from WP locale.
        if (function_exists('is_rtl') && is_rtl()) {
            return 'ar';
        }
        if (function_exists('get_locale')) {
            $loc = (string) get_locale();
            if (strpos($loc, 'ar') === 0) {
                return 'ar';
            }
        }
        return 'en';
    }

    /**
     * For wp_localize_script: build a single payload of common JS strings
     * so admin.js can read them via AetosSeoData.i18n.<key> without
     * hardcoding Arabic in JS.
     *
     * @return array<string,string>
     */
    public static function js_payload(): array
    {
        return [
            'lang'                => self::lang(),
            'is_rtl'              => self::is_arabic() ? '1' : '0',
            'confirm_reset_data'  => self::tr(
                'This will erase all scan data. Continue?',
                'سيتم حذف كل بيانات الفحص. متأكد؟'
            ),
            'confirm_factory_reset' => self::tr(
                'Factory reset will erase scans + integrations + settings. Continue?',
                'سيحذف Factory Reset الفحوصات والتكاملات والإعدادات. هل أنت متأكد؟'
            ),
            'loading'             => self::tr('Loading…', 'جاري التحميل…'),
            'saving'              => self::tr('Saving…', 'جاري الحفظ…'),
            'saved'               => self::tr('Saved', 'تم الحفظ'),
            'failed'              => self::tr('Failed', 'فشل'),
            'retrying'            => self::tr('Retrying…', 'إعادة المحاولة…'),
            'connection_error'    => self::tr('Connection error', 'خطأ اتصال'),
            'copy'                => self::tr('Copy', 'نسخ'),
            'copied'              => self::tr('Copied', 'تم النسخ'),
            'prompt_copied'       => self::tr('Copied - paste into any AI assistant', 'اتنسخ، الصقه في أي مساعد AI'),
            'send'                => self::tr('Send', 'إرسال'),
            'cancel'              => self::tr('Cancel', 'إلغاء'),
            'view_details'        => self::tr('View details', 'عرض التفاصيل'),
            'mark_done'           => self::tr('Mark done', 'تم الحل'),
            'retest'              => self::tr('Retest', 'إعادة فحص'),
            'no_data'             => self::tr('No data', 'لا توجد بيانات'),
            'thinking'            => self::tr('Thinking…', 'يفكر…'),
        ];
    }

    /**
     * Reset the static cache (used by tests).
     */
    public static function reset_cache(): void
    {
        self::$cached_lang = null;
    }
}