'use client';

import React, { createContext, useContext, useState, useCallback, ReactNode, useEffect } from 'react';
import en from '@/i18n/en.json';
import es from '@/i18n/es.json';
import ptBR from '@/i18n/pt-BR.json';

type Locale = 'en' | 'es' | 'pt-BR';

interface I18nContextType {
    locale: Locale;
    setLocale: (locale: Locale) => void;
    t: (key: string, params?: Record<string, string | number>) => string;
}

const dictionaries: Record<Locale, typeof en> = {
    en,
    es,
    'pt-BR': ptBR,
};

const I18nContext = createContext<I18nContextType | null>(null);

const localeStorageKey = 'locale';

const normalizeLocale = (language: string): Locale => {
    if (language.startsWith('pt')) return 'pt-BR';
    if (language.startsWith('es')) return 'es';
    return 'en';
};

const getInitialLocale = (): Locale => {
    if (typeof window === 'undefined') return 'en';
    const storedLocale = localStorage.getItem(localeStorageKey);
    if (storedLocale && storedLocale in dictionaries) {
        return storedLocale as Locale;
    }
    // Default to English instead of browser language for consistency
    return 'en';
};

export function I18nProvider({ children }: { children: ReactNode }) {
    // FIX: Initialize with 'en' to match Server-Side Rendering (SSR)
    // This prevents hydration mismatch errors.
    const [locale, setLocaleState] = useState<Locale>('en');

    const setLocale = (newLocale: Locale) => {
        console.log(`[I18n] Setting locale to: ${newLocale}`);
        setLocaleState(newLocale);
    };

    const t = useCallback((key: string, params?: Record<string, string | number>) => {
        const keys = key.split('.');
        let value: unknown = dictionaries[locale];

        for (const k of keys) {
            if (value && typeof value === 'object' && value !== null && k in value) {
                value = (value as Record<string, unknown>)[k];
            } else {
                return key; // Return key if not found
            }
        }

        if (typeof value !== 'string') return key;

        // Replace parameters like {count}, {time}, {year}
        if (params) {
            return Object.entries(params).reduce(
                (str, [paramKey, paramValue]) => str.replace(`{${paramKey}}`, String(paramValue)),
                value
            );
        }

        return value;
    }, [locale]);

    // Sync from localStorage on mount (Client-side only)
    useEffect(() => {
        const stored = getInitialLocale();
        if (stored !== 'en') {
            console.log('[I18n] Restoring locale from storage on client:', stored);
            setLocaleState(stored);
        }
    }, []);

    useEffect(() => {
        if (typeof window === 'undefined') return;
        localStorage.setItem(localeStorageKey, locale);
        document.documentElement.lang = locale;
    }, [locale]);

    return (
        <I18nContext.Provider value={{ locale, setLocale, t }}>
            {children}
        </I18nContext.Provider>
    );
}

export function useI18n() {
    const context = useContext(I18nContext);
    if (!context) {
        throw new Error('useI18n must be used within an I18nProvider');
    }
    return context;
}

export function useTranslation() {
    const { t, locale, setLocale } = useI18n();
    return { t, locale, setLocale };
}

export const locales: { code: Locale; name: string; flag: string }[] = [
    { code: 'en', name: 'English', flag: '🇺🇸' },
    { code: 'es', name: 'Español', flag: '🇪🇸' },
    { code: 'pt-BR', name: 'Português', flag: '🇧🇷' },
];
