import { useMemo, useState } from 'react';
import { useForm } from 'react-hook-form';
import { zodResolver } from '@hookform/resolvers/zod';
import { useNavigate, useSearch } from '@tanstack/react-router';
import { useTranslation } from 'react-i18next';
import { z } from 'zod';
import { Button } from '@/components/ui/button';
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
import { Input } from '@/components/ui/input';
import { Label } from '@/components/ui/label';
import { useAuth } from '@/contexts/auth-context';
import { NetworkError, ProblemDetailsError } from '@/lib/api-client';

export function LoginPage() {
    const { t } = useTranslation();
    const { login } = useAuth();
    const navigate = useNavigate();
    const search = useSearch({ strict: false }) as { redirect?: string };
    const [serverError, setServerError] = useState<string | null>(null);

    const schema = useMemo(
        () =>
            z.object({
                email: z
                    .string()
                    .min(1, t('login.errors.emailRequired'))
                    .email(t('login.errors.emailInvalid')),
                password: z.string().min(1, t('login.errors.passwordRequired')),
            }),
        [t],
    );

    type FormValues = z.infer<typeof schema>;

    const {
        register,
        handleSubmit,
        formState: { errors, isSubmitting },
    } = useForm<FormValues>({
        resolver: zodResolver(schema),
        defaultValues: { email: '', password: '' },
    });

    const onSubmit = handleSubmit(async (values) => {
        setServerError(null);
        try {
            await login(values.email, values.password);
            await navigate({ to: search.redirect ?? '/dashboard' });
        } catch (err) {
            if (err instanceof ProblemDetailsError && err.status === 401) {
                setServerError(t('login.errors.invalidCredentials'));
            } else if (err instanceof NetworkError) {
                setServerError(t('errors.network'));
            } else {
                setServerError(t('login.errors.generic'));
            }
        }
    });

    return (
        <div className="flex min-h-svh items-center justify-center bg-secondary/40 p-4">
            <Card className="w-full max-w-sm">
                <CardHeader>
                    <CardTitle>{t('login.title')}</CardTitle>
                    <CardDescription>{t('login.subtitle')}</CardDescription>
                </CardHeader>
                <CardContent>
                    <form onSubmit={onSubmit} noValidate className="space-y-4">
                        {serverError !== null && (
                            <div
                                role="alert"
                                data-testid="login-error"
                                className="rounded-md border border-destructive/50 bg-destructive/10 px-3 py-2 text-sm text-destructive"
                            >
                                {serverError}
                            </div>
                        )}

                        <div className="space-y-2">
                            <Label htmlFor="email">{t('login.email')}</Label>
                            <Input
                                id="email"
                                type="email"
                                autoComplete="email"
                                placeholder={t('login.emailPlaceholder')}
                                data-testid="login-email-input"
                                aria-invalid={errors.email !== undefined}
                                {...register('email')}
                            />
                            {errors.email && (
                                <p
                                    className="text-sm text-destructive"
                                    data-testid="login-email-error"
                                >
                                    {errors.email.message}
                                </p>
                            )}
                        </div>

                        <div className="space-y-2">
                            <Label htmlFor="password">{t('login.password')}</Label>
                            <Input
                                id="password"
                                type="password"
                                autoComplete="current-password"
                                data-testid="login-password-input"
                                aria-invalid={errors.password !== undefined}
                                {...register('password')}
                            />
                            {errors.password && (
                                <p
                                    className="text-sm text-destructive"
                                    data-testid="login-password-error"
                                >
                                    {errors.password.message}
                                </p>
                            )}
                        </div>

                        <Button
                            type="submit"
                            className="w-full"
                            disabled={isSubmitting}
                            data-testid="login-form-submit-button"
                        >
                            {isSubmitting ? t('login.submitting') : t('login.submit')}
                        </Button>
                    </form>
                </CardContent>
            </Card>
        </div>
    );
}