interface UserProfile {
  home_airports: string[]
  default_adults: number
  default_children: number
  default_infants: number
  locale: string
  show_origin_time: boolean
}

export function useUserPreferences() {
  const user = useSupabaseUser()
  const profile = useState<UserProfile | null>('user-profile', () => null)
  const loading = useState<boolean>('user-profile-loading', () => false)

  let fetchPromise: Promise<void> | null = null

  async function fetchProfile() {
    if (!user.value) return
    if (fetchPromise) return fetchPromise
    loading.value = true
    fetchPromise = (async () => {
      try {
        const data = await $fetch<UserProfile>('/api/profile')
        profile.value = data
      } catch {
        profile.value = null
      } finally {
        loading.value = false
        fetchPromise = null
      }
    })()
    return fetchPromise
  }

  async function updateProfile(updates: Partial<UserProfile>) {
    if (!user.value) return
    try {
      const data = await $fetch<UserProfile>('/api/profile', {
        method: 'PATCH',
        body: updates
      })
      profile.value = data
    } catch {
      // silent
    }
  }

  const homeAirports = computed(() => profile.value?.home_airports ?? [])

  const defaultPassengers = computed(() => ({
    adult: profile.value?.default_adults ?? 1,
    child: profile.value?.default_children ?? 0,
    infant: profile.value?.default_infants ?? 0
  }))

  watch(user, (u) => {
    if (u) fetchProfile()
    else profile.value = null
  }, { immediate: true })

  return { profile, loading, homeAirports, defaultPassengers, fetchProfile, updateProfile }
}