import { useEffect, useRef, useState } from 'react'
import {
  createBarcodeDecoder,
  openCameraStream,
  stopCameraStream,
  vibrateOnScan,
} from '@/utils/barcode'
import { isCameraAvailable, isCameraBlockedByStandaloneIos } from '@/utils/device'

export type BarcodeReaderStatus =
  | 'starting'
  | 'scanning'
  | 'denied'
  | 'insecure'
  | 'standaloneIos'
  | 'error'

/** Kare çözme aralığı. Her karede çözmek mobilde pili hızla tüketir. */
const DECODE_INTERVAL_MS = 180

/** Aynı kodun arka arkaya birden çok kez okunmasını engelleyen pencere. */
const DUPLICATE_WINDOW_MS = 1500

/**
 * Kamerayı açar, kareleri çözer ve okunan kodu bildirir.
 *
 * `onDetect` her okumada yeniden bağlanabildiği için ref üzerinden tutulur;
 * aksi hâlde her render kamerayı kapatıp yeniden açardı.
 */
export const useBarcodeReader = ({
  active,
  onDetect,
}: {
  active: boolean
  onDetect: (code: string) => void
}) => {
  const videoRef = useRef<HTMLVideoElement>(null)
  const onDetectRef = useRef(onDetect)
  const [status, setStatus] = useState<BarcodeReaderStatus>('starting')

  onDetectRef.current = onDetect

  useEffect(() => {
    if (!active) return

    if (isCameraBlockedByStandaloneIos()) {
      setStatus('standaloneIos')
      return
    }

    if (!isCameraAvailable()) {
      setStatus('insecure')
      return
    }

    const video = videoRef.current
    let stream: MediaStream | undefined
    let timer: number | undefined
    let cancelled = false
    let lastCode = ''
    let lastCodeAt = 0

    const start = async () => {
      setStatus('starting')
      try {
        const [cameraStream, decode] = await Promise.all([
          openCameraStream(),
          createBarcodeDecoder(),
        ])

        if (cancelled) {
          stopCameraStream(cameraStream)
          return
        }

        if (!video) return
        stream = cameraStream

        video.srcObject = cameraStream
        await video.play()
        setStatus('scanning')

        const tick = async () => {
          if (cancelled) return

          try {
            const code = await decode(video)
            const now = Date.now()
            if (code && (code !== lastCode || now - lastCodeAt > DUPLICATE_WINDOW_MS)) {
              lastCode = code
              lastCodeAt = now
              vibrateOnScan()
              onDetectRef.current(code)
            }
          } catch {
            // Tek bir karenin çözülememesi tarama döngüsünü durdurmaz.
          }

          if (!cancelled) {
            timer = window.setTimeout(tick, DECODE_INTERVAL_MS)
          }
        }

        tick()
      } catch (error) {
        if (cancelled) return
        const name = (error as DOMException)?.name
        setStatus(name === 'NotAllowedError' || name === 'SecurityError' ? 'denied' : 'error')
      }
    }

    start()

    return () => {
      cancelled = true
      if (timer) window.clearTimeout(timer)
      stopCameraStream(stream)
      if (video) video.srcObject = null
    }
  }, [active])

  return { videoRef, status }
}