import { useState, useEffect } from 'react';
import { useParams, useRouter } from 'next/navigation';

type Locale = 'zh-CN' | 'zh-TW' | 'en';

interface TranslationData {
    [key: string]: any;
}

const translations: Record<Locale, Record<string, TranslationData>> = {
    'zh-CN': {},
    'zh-TW': {},
    en: {},
};

// Load translation files dynamically
const loadTranslations = async (locale: Locale, namespace: string): Promise<TranslationData> => {
    if (translations[locale][namespace]) {
        return translations[locale][namespace];
    }

    try {
        const response = await fetch(`/locales/${locale}/${namespace}.json`);
        if (!response.ok) {
            throw new Error(`HTTP ${response.status}`);
        }
        const data = await response.json();
        translations[locale][namespace] = data;
        return data;
    } catch (error) {
        console.error(`Failed to load translation: ${locale}/${namespace}`, error);
        return {};
    }
};

export const useTranslation = (namespace: string = 'common') => {
    const params = useParams();
    const router = useRouter();
    const urlLocale = params?.locale as Locale;
    
    const [locale, setLocale] = useState<Locale>(urlLocale || 'zh-CN');
    const [translations, setTranslations] = useState<TranslationData>({});
    const [loading, setLoading] = useState(true);

    useEffect(() => {
        // 如果URL中有locale参数，优先使用URL中的语言
        if (urlLocale && urlLocale !== locale) {
            setLocale(urlLocale);
        }
    }, [urlLocale, locale]);

    useEffect(() => {
        const loadData = async () => {
            setLoading(true);
            const data = await loadTranslations(locale, namespace);
            setTranslations(data);
            setLoading(false);
        };

        loadData();
    }, [locale, namespace]);

    const changeLocale = (newLocale: Locale) => {
        // 更新localStorage
        localStorage.setItem('language', newLocale);
        
        // 构建新的URL路径
        const currentPath = window.location.pathname;
        const pathWithoutLocale = currentPath.replace(/^\/[^\/]+/, '');
        const newPath = `/${newLocale}${pathWithoutLocale}`;
        
        // 导航到新的语言路径
        router.push(newPath);
    };

    const t = (key: string, defaultValue?: string): string => {
        const keys = key.split('.');
        let value = translations;

        for (const k of keys) {
            if (value && typeof value === 'object' && k in value) {
                value = value[k];
            } else {
                return defaultValue || key;
            }
        }

        return typeof value === 'string' ? value : defaultValue || key;
    };

    return {
        t,
        locale,
        setLocale: changeLocale,
        loading,
    };
};

// 语言切换工具函数
export const getLocalizedPath = (path: string, locale: Locale): string => {
    return `/${locale}${path}`;
};

// 验证locale是否有效
export const isValidLocale = (locale: string): locale is Locale => {
    return ['zh-CN', 'zh-TW', 'en'].includes(locale);
};

export type { Locale };