import Quagga from '@ericblade/quagga2'

export const useBarcodeScanner = (onScan, targetElementGetter) => {
  const useScannerMode = ref(false)
  const showScanner = ref(false)
  const scannerError = ref('')
  const isProcessingScan = ref(false)
  const isInitialized = ref(false)

  // Load scanner preference from localStorage
  onMounted(() => {
    if (typeof window !== 'undefined') {
      const savedPreference = localStorage.getItem('useBarcodeScanner')
      useScannerMode.value = savedPreference === 'true'

      if (useScannerMode.value) {
        // Delay to allow component to mount
        setTimeout(() => {
          startScanner()
        }, 200)
      }
    }
  })

  // Cleanup on unmount
  onBeforeUnmount(() => {
    stopScanner()
  })

  const startScanner = async () => {
    if (!useScannerMode.value) return

    showScanner.value = true
    scannerError.value = ''

    try {
      // Wait for component to mount
      await nextTick()

      // Get the target element from the DOM
      let targetElement = null
      let retries = 0

      while (!targetElement && retries < 20) {
        if (targetElementGetter) {
          targetElement = targetElementGetter()
        } else {
          // Fallback: find by class name
          targetElement = document.querySelector('.scanner-video-container-inline')
        }

        if (!targetElement) {
          await new Promise(resolve => setTimeout(resolve, 100))
          retries++
        }
      }

      if (!targetElement) {
        scannerError.value = 'Video element not found'
        return
      }

      // Initialize Quagga with back camera preference
      Quagga.init({
        inputStream: {
          type: 'LiveStream',
          target: targetElement,
          constraints: {
            facingMode: 'environment', // Always prefer back camera
            width: { min: 640, ideal: 1280, max: 1920 },
            height: { min: 480, ideal: 720, max: 1080 }
          }
        },
        locator: {
          patchSize: 'medium',
          halfSample: true
        },
        numOfWorkers: navigator.hardwareConcurrency || 4,
        decoder: {
          readers: [
            'code_128_reader',
            'ean_reader',
            'ean_8_reader',
            'code_39_reader',
            'code_39_vin_reader',
            'codabar_reader',
            'upc_reader',
            'upc_e_reader',
            'i2of5_reader'
          ],
          multiple: false
        },
        locate: true
      }, (err) => {
        if (err) {
          console.error('Quagga initialization error:', err)
          scannerError.value = 'Failed to start camera: ' + err.message
          return
        }

        isInitialized.value = true
        Quagga.start()

        // Add detection handler
        Quagga.onDetected((result) => {
          if (result && result.codeResult && !isProcessingScan.value) {
            isProcessingScan.value = true
            const scannedCode = result.codeResult.code

            // Call the callback with scanned code
            if (onScan) {
              onScan(scannedCode)
            }

            // Prevent scanning for 1.15 seconds to avoid duplicate scans
            setTimeout(() => {
              isProcessingScan.value = false
            }, 1150)
          }
        })
      })
    } catch (err) {
      console.error('Scanner error:', err)
      scannerError.value = 'Failed to start camera: ' + err.message
    }
  }

  const stopScanner = () => {
    if (isInitialized.value) {
      Quagga.stop()
      Quagga.offDetected()
      isInitialized.value = false
    }
    showScanner.value = false
    scannerError.value = ''
  }

  return {
    useScannerMode,
    showScanner,
    scannerError,
    isProcessingScan,
    startScanner,
    stopScanner
  }
}