import { zodResolver } from '@hookform/resolvers/zod'
import { useEffect } from 'react'
import { useQuery, useQueryClient } from '@tanstack/react-query'
import { Home, Info, Loader2, UserPlus, Users } from 'lucide-react'
import { Controller, useForm, useWatch } from 'react-hook-form'
import { Link, useSearchParams } from 'react-router'
import { toast } from 'sonner'
import { FormError, FormField, PasswordInput } from '@/components/form-field'
import { paths } from '@/components/layout/nav-items'
import { Button } from '@/components/ui/button'
import { Input } from '@/components/ui/input'
import { api, ApiError } from '@/lib/api'
import { useRegister } from '@/lib/auth'
import { queryKeys } from '@/lib/query'
import { t } from '@/lib/strings'
import { cn } from '@/lib/utils'
import { AuthShell } from './auth-shell'
import type { RegistrationInfo } from '@/types/RegistrationInfo'
import { normalizeInviteCode, registerSchema, type RegisterForm } from './schemas'

const s = t.auth.register

export function RegisterPage() {
  const registerAccount = useRegister()
  const [params] = useSearchParams()
  // Davet bağlantısı: /kayit?davet=ABCD-EFGH → "Davetle katıl" seçili ve kod dolu
  const invite = params.get('davet') ?? ''

  // Sunucu politikası (REGISTRATION): yeni hane kurulabilir mi?
  const qc = useQueryClient()
  const info = useQuery({
    queryKey: queryKeys.registration,
    queryFn: () => api.get<RegistrationInfo>('/auth/registration'),
  })
  const newAllowed = info.data?.new_household_allowed ?? true

  const {
    register,
    control,
    handleSubmit,
    setError,
    setValue,
    formState: { errors, isSubmitting },
  } = useForm<RegisterForm>({
    resolver: zodResolver(registerSchema),
    mode: 'onTouched',
    defaultValues: {
      name: '',
      email: '',
      password: '',
      mode: invite ? 'join' : 'new',
      household_name: '',
      invite_code: invite,
    },
  })
  // Kayıt kapalıysa yalnızca "Davetle katıl"
  useEffect(() => {
    if (!newAllowed) setValue('mode', 'join')
  }, [newAllowed, setValue])

  const mode = useWatch({ control, name: 'mode' })
  const name = useWatch({ control, name: 'name' }).trim()

  const onSubmit = handleSubmit(async (v) => {
    try {
      const me = await registerAccount.mutateAsync({
        name: v.name,
        email: v.email,
        password: v.password,
        ...(v.mode === 'join'
          ? { invite_code: normalizeInviteCode(v.invite_code) }
          : { household_name: v.household_name || undefined }),
      })
      toast.success(v.mode === 'join' ? s.joined(me.household.name) : s.welcome(me.household.name))
    } catch (e) {
      if (!(e instanceof ApiError)) return setError('root', { message: String(e) })
      // Sunucu hatasını ilgili alana bağla
      if (e.code === 'conflict') setError('email', { message: e.message }, { shouldFocus: true })
      else if (e.code === 'registration_closed') {
        // Bu arada başka biri ilk haneyi kurmuş olabilir → bilgiyi tazele, formu davete çevir
        await qc.invalidateQueries({ queryKey: queryKeys.registration })
        setError('root', { message: e.message })
      } else if (v.mode === 'join' && e.code === 'bad_request' && e.message.includes('Davet'))
        setError('invite_code', { message: e.message }, { shouldFocus: true })
      else setError('root', { message: e.message })
    }
  })

  const donus = params.get('donus')
  const loginLink = donus ? `${paths.login}?donus=${encodeURIComponent(donus)}` : paths.login

  return (
    <AuthShell
      title={s.title}
      description={s.description}
      footer={
        <>
          {s.hasAccount}{' '}
          <Link
            to={loginLink}
            className="font-medium text-primary underline-offset-4 hover:underline"
          >
            {s.toLogin}
          </Link>
        </>
      }
    >
      <form onSubmit={onSubmit} noValidate className="space-y-5">
        <FormField label={s.name} error={errors.name}>
          {(f) => <Input {...f} {...register('name')} autoComplete="given-name" autoFocus />}
        </FormField>

        <FormField label={s.email} error={errors.email}>
          {(f) => (
            <Input
              {...f}
              {...register('email')}
              type="email"
              inputMode="email"
              autoComplete="email"
              autoCapitalize="none"
            />
          )}
        </FormField>

        <FormField label={s.password} error={errors.password} hint={s.passwordHint}>
          {(f) => <PasswordInput {...f} {...register('password')} autoComplete="new-password" />}
        </FormField>

        {/* Yeni hane mi, davetle katılma mı? */}
        <fieldset className="space-y-3">
          <legend className="mb-2 text-sm font-medium">{s.modeLabel}</legend>
          {!newAllowed && (
            <p className="flex gap-2 rounded-lg bg-muted px-3 py-2.5 text-sm text-muted-foreground">
              <Info className="mt-0.5 size-4 shrink-0" aria-hidden />
              {s.closedNote}
            </p>
          )}
          {newAllowed && (
            <Controller
              control={control}
              name="mode"
              render={({ field }) => (
                <div
                  role="radiogroup"
                  className="grid grid-cols-2 gap-2 rounded-lg border bg-muted p-1"
                >
                  {(
                    [
                      ['new', s.modeNew, Home],
                      ['join', s.modeJoin, Users],
                    ] as const
                  ).map(([value, label, Icon]) => (
                    <button
                      key={value}
                      type="button"
                      role="radio"
                      aria-checked={field.value === value}
                      onClick={() => field.onChange(value)}
                      className={cn(
                        'flex min-h-11 items-center justify-center gap-2 rounded-md text-sm font-medium text-muted-foreground transition-colors',
                        field.value === value && 'bg-background text-foreground shadow-sm',
                      )}
                    >
                      <Icon className="size-4" aria-hidden />
                      {label}
                    </button>
                  ))}
                </div>
              )}
            />
          )}

          {mode === 'new' ? (
            <FormField
              label={s.householdName}
              error={errors.household_name}
              hint={s.householdHint(name)}
            >
              {(f) => (
                <Input
                  {...f}
                  {...register('household_name')}
                  placeholder={name ? `${name} Hanesi` : ''}
                />
              )}
            </FormField>
          ) : (
            <FormField label={s.inviteCode} error={errors.invite_code} hint={s.inviteHint}>
              {(f) => (
                <Input
                  {...f}
                  {...register('invite_code')}
                  autoCapitalize="characters"
                  autoComplete="off"
                  spellCheck={false}
                  maxLength={12}
                  className="font-mono tracking-widest uppercase"
                />
              )}
            </FormField>
          )}
        </fieldset>

        <FormError message={errors.root?.message} />

        <Button type="submit" size="lg" className="w-full" disabled={isSubmitting}>
          {isSubmitting ? <Loader2 className="animate-spin" /> : <UserPlus />}
          {isSubmitting ? s.submitting : s.submit}
        </Button>
      </form>
    </AuthShell>
  )
}