// src/app/auth/login/page.tsx
'use client'

import { useState, useEffect } from 'react'
import { useForm } from 'react-hook-form'
import { useRouter } from 'next/navigation'
import Link from 'next/link'

type FormData = { username: string; password: string }

export default function LoginPage() {
  const router = useRouter()
  const { register, handleSubmit, formState: { errors, isSubmitting } } = useForm<FormData>()
  const [apiError, setApiError] = useState<string | null>(null)

  useEffect(() => {
    if (typeof window !== 'undefined' && localStorage.getItem('token')) {
      router.push('/dashboard')
    }
  }, [router])

  async function onSubmit(data: FormData) {
    setApiError(null)
    try {
      const res = await fetch(
        `/api/auth/login/`,
        {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify(data),
        }
      )
      if (!res.ok) {
        const json = await res.json()
        setApiError(json.detail || 'Ошибка входа')
        return
      }
      const { access } = await res.json()
      localStorage.setItem('token', access)
      router.push('/dashboard')
    } catch {
      setApiError('Сетевая ошибка')
    }
  }

  return (
    <div className="min-vh-100 d-flex align-items-center justify-content-center bg-light">
      <div className="container">
        <div className="row justify-content-center">
          <div className="col-md-6 col-lg-5">
            <div className="card shadow-lg border-0 rounded-4">
              <div className="card-body p-5">
                <div className="text-center mb-4">
                  <img 
                    src="/assets/img/CAT.png" 
                    alt="CatLink" 
                    width="80" 
                    height="80" 
                    className="mb-3"
                  />
                  <h2 className="fw-bold text-primary">Добро пожаловать!</h2>
                  <p className="text-muted">Войдите в свой аккаунт CatLink</p>
                </div>

                {apiError && (
                  <div className="alert alert-danger" role="alert">
                    {apiError}
                  </div>
                )}

                <form onSubmit={handleSubmit(onSubmit)}>
                  <div className="mb-3">
                    <label htmlFor="username" className="form-label">Имя пользователя</label>
                    <input
                      id="username"
                      type="text"
                      placeholder="Введите имя пользователя"
                      className={`form-control form-control-lg ${errors.username ? 'is-invalid' : ''}`}
                      {...register('username', { required: 'Введите имя пользователя' })}
                    />
                    {errors.username && (
                      <div className="invalid-feedback">{errors.username.message}</div>
                    )}
                  </div>

                  <div className="mb-4">
                    <label htmlFor="password" className="form-label">Пароль</label>
                    <input
                      id="password"
                      type="password"
                      placeholder="Введите пароль"
                      className={`form-control form-control-lg ${errors.password ? 'is-invalid' : ''}`}
                      {...register('password', { required: 'Введите пароль' })}
                    />
                    {errors.password && (
                      <div className="invalid-feedback">{errors.password.message}</div>
                    )}
                  </div>

                  <button
                    type="submit"
                    disabled={isSubmitting}
                    className="btn btn-primary btn-lg w-100 mb-3"
                  >
                    {isSubmitting ? (
                      <>
                        <span className="spinner-border spinner-border-sm me-2" role="status" aria-hidden="true"></span>
                        Входим...
                      </>
                    ) : (
                      'Войти'
                    )}
                  </button>
                </form>

                <div className="text-center">
                  <p className="text-muted mb-0">
                    Нет аккаунта?{' '}
                    <Link href="/auth/register" className="text-primary text-decoration-none fw-bold">
                      Зарегистрироваться
                    </Link>
                  </p>
                </div>
              </div>
            </div>
          </div>
        </div>
      </div>
    </div>
  )
}