interface GoogleCredentialResponse {
  credential: string
  select_by: string
}

declare global {
  interface Window {
    google?: {
      accounts: {
        id: {
          initialize: (config: {
            client_id: string
            callback: (response: GoogleCredentialResponse) => void
            auto_select?: boolean
          }) => void
          prompt: (callback?: (notification: { isNotDisplayed: () => boolean; isSkippedMoment: () => boolean }) => void) => void
          renderButton: (parent: HTMLElement, config: Record<string, unknown>) => void
        }
      }
    }
  }
}

export function useGoogleAuth() {
  const config = useRuntimeConfig()
  const googleClientId = config.public.googleClientId as string
  const loading = ref(false)
  const error = ref<string | null>(null)

  function loadGoogleScript(): Promise<void> {
    return new Promise((resolve, reject) => {
      if (window.google) {
        resolve()
        return
      }

      const existingScript = document.querySelector('script[src="https://accounts.google.com/gsi/client"]')
      if (existingScript) {
        existingScript.addEventListener('load', () => resolve(), { once: true })
        return
      }

      const script = document.createElement('script')
      script.src = 'https://accounts.google.com/gsi/client'
      script.async = true
      script.defer = true
      script.onload = () => resolve()
      script.onerror = () => reject(new Error('Gagal memuat Google Identity Services'))
      document.head.appendChild(script)
    })
  }

  async function signInWithGoogle(onResult?: (result: any) => void, onError?: (msg: string) => void) {
    error.value = null
    loading.value = true

    try {
      await loadGoogleScript()

      if (!googleClientId) {
        throw new Error('Google Client ID tidak dikonfigurasi')
      }

      window.google!.accounts.id.initialize({
        client_id: googleClientId,
        callback: async (response: GoogleCredentialResponse) => {
          try {
            const apiBase = config.public.apiBase
            const result = await $fetch(`${apiBase}/auth/google-login`, {
              method: 'POST',
              body: { credential: response.credential },
            })
            onResult?.(result)
          } catch (e: any) {
            const detail = e?.data?.detail
            const msg = detail?.message || 'Gagal masuk dengan Google'
            error.value = msg
            onError?.(msg)
          } finally {
            loading.value = false
          }
        },
        auto_select: false,
      })

      window.google!.accounts.id.prompt((notification) => {
        if (notification.isNotDisplayed()) {
          loading.value = false
          onError?.('Popup Google tidak dapat ditampilkan. Silakan coba metode lain.')
        }
      })
    } catch (e: any) {
      error.value = e.message
      loading.value = false
      onError?.(e.message)
    }
  }

  return {
    loading,
    error,
    signInWithGoogle,
  }
}