import {useState} from 'react';
import {Link, useNavigate} from 'react-router-dom';
import {useTranslation} from 'react-i18next';
import {useForm} from 'react-hook-form';
import {zodResolver} from '@hookform/resolvers/zod';

import {registrationSchema} from '../utils/validation.js';

const BACKEND_ERROR_KEY = {
    EMAIL_ALREADY_IN_USE: 'REGISTRATION.ERROR_EMAIL_IN_USE',
    INVALID_INVITATION_CODE: 'REGISTRATION.ERROR_INVALID_INVITE_CODE',
    STEAM_ID_ALREADY_IN_USE: 'REGISTRATION.ERROR_STEAM_ID_IN_USE',
};

const inputClass =
    'w-full px-4 py-2 border border-slate-300 dark:border-slate-600 rounded-lg bg-slate-50 dark:bg-slate-700 text-slate-900 dark:text-white focus:ring-2 focus:ring-blue-500 focus:outline-none';
const inputErrorClass =
    'w-full px-4 py-2 border border-red-500 dark:border-red-500 rounded-lg bg-slate-50 dark:bg-slate-700 text-slate-900 dark:text-white focus:ring-2 focus:ring-red-500 focus:outline-none';

export default function RegistrationPage() {
    const {t} = useTranslation();
    const navigate = useNavigate();
    const [feedback, setFeedback] = useState({message: '', isError: false});

    const {
        register,
        handleSubmit,
        formState: {errors, isSubmitting},
    } = useForm({
        resolver: zodResolver(registrationSchema),
        defaultValues: {
            email: '',
            password: '',
            passwordConfirmation: '',
            inviteCode: '',
            steamId: '',
        },
    });

    const onSubmit = async (values) => {
        setFeedback({message: '', isError: false});
        try {
            const apiUrl = `${import.meta.env.VITE_API_URL}/api/registration/new`;
            const response = await fetch(apiUrl, {
                method: 'POST',
                headers: {'Content-Type': 'application/json'},
                body: JSON.stringify({
                    email: values.email,
                    password: values.password,
                    inviteCode: values.inviteCode,
                    steamId: values.steamId,
                }),
            });

            if (response.ok) {
                setFeedback({message: t('REGISTRATION.SUCCESS'), isError: false});
                setTimeout(() => navigate('/login'), 800);
                return;
            }

            const data = await response.json().catch(() => ({}));
            const mappedKey = BACKEND_ERROR_KEY[data.code];
            setFeedback({
                message: mappedKey ? t(mappedKey) : data.message || t('REGISTRATION.ERROR_GENERIC'),
                isError: true,
            });
        } catch (err) {
            console.error('Registration API error:', err);
            setFeedback({message: t('INFO.ERROR.NETWORK_FAILURE'), isError: true});
        }
    };

    const renderError = (field) =>
        errors[field] && (
            <p className="mt-1 text-sm text-red-600 dark:text-red-400">{t(errors[field].message)}</p>
        );

    return (
        <div className="flex min-h-screen items-center justify-center bg-slate-50 dark:bg-slate-900 px-4 py-8">
            <div className="w-full max-w-md bg-white dark:bg-slate-800 rounded-xl shadow-lg p-8">
                <h2 className="text-2xl font-bold text-slate-900 dark:text-white mb-6 text-center">
                    {t('REGISTRATION.TITLE')}
                </h2>

                <form onSubmit={handleSubmit(onSubmit)} className="space-y-4" noValidate>
                    <div>
                        <label htmlFor="email" className="block text-sm font-medium text-slate-700 dark:text-slate-300 mb-1">
                            {t('REGISTRATION.EMAIL')}
                        </label>
                        <input
                            id="email"
                            type="email"
                            autoComplete="email"
                            className={errors.email ? inputErrorClass : inputClass}
                            {...register('email')}
                        />
                        {renderError('email')}
                    </div>

                    <div>
                        <label htmlFor="password" className="block text-sm font-medium text-slate-700 dark:text-slate-300 mb-1">
                            {t('REGISTRATION.PASSWORD')}
                        </label>
                        <input
                            id="password"
                            type="password"
                            autoComplete="new-password"
                            className={errors.password ? inputErrorClass : inputClass}
                            {...register('password')}
                        />
                        {renderError('password')}
                    </div>

                    <div>
                        <label htmlFor="passwordConfirmation" className="block text-sm font-medium text-slate-700 dark:text-slate-300 mb-1">
                            {t('REGISTRATION.PASSWORD_CONFIRMATION')}
                        </label>
                        <input
                            id="passwordConfirmation"
                            type="password"
                            autoComplete="new-password"
                            className={errors.passwordConfirmation ? inputErrorClass : inputClass}
                            {...register('passwordConfirmation')}
                        />
                        {renderError('passwordConfirmation')}
                    </div>

                    <div>
                        <label htmlFor="inviteCode" className="block text-sm font-medium text-slate-700 dark:text-slate-300 mb-1">
                            {t('REGISTRATION.INVITE_CODE')}
                        </label>
                        <input
                            id="inviteCode"
                            type="text"
                            className={errors.inviteCode ? inputErrorClass : inputClass}
                            {...register('inviteCode')}
                        />
                        {renderError('inviteCode')}
                    </div>

                    <div>
                        <label htmlFor="steamId" className="block text-sm font-medium text-slate-700 dark:text-slate-300 mb-1">
                            {t('REGISTRATION.STEAM_ID')}
                        </label>
                        <input
                            id="steamId"
                            type="text"
                            inputMode="numeric"
                            className={errors.steamId ? inputErrorClass : inputClass}
                            {...register('steamId')}
                        />
                        {renderError('steamId')}
                    </div>

                    <button
                        type="submit"
                        disabled={isSubmitting}
                        className="w-full py-2 px-4 bg-blue-600 hover:bg-blue-700 disabled:bg-blue-400 text-white font-semibold rounded-lg transition-colors duration-200"
                    >
                        {isSubmitting ? '...' : t('REGISTRATION.SUBMIT')}
                    </button>
                </form>

                {feedback.message && (
                    <div
                        className={`mt-6 p-4 rounded-lg text-sm text-center ${
                            feedback.isError
                                ? 'bg-red-100 text-red-700 dark:bg-red-900/30 dark:text-red-400'
                                : 'bg-green-100 text-green-700 dark:bg-green-900/30 dark:text-green-400'
                        }`}
                    >
                        {feedback.message}
                    </div>
                )}

                <p className="mt-6 text-sm text-center text-slate-600 dark:text-slate-400">
                    {t('REGISTRATION.HAVE_ACCOUNT')}{' '}
                    <Link to="/login" className="text-blue-600 hover:text-blue-500 font-semibold">
                        {t('MAIN.LOGIN')}
                    </Link>
                </p>
            </div>
        </div>
    );
}