import { onHide, onShow, onUnload } from '@dcloudio/uni-app'

const androidKeyCodeMap = {
  7: '0',
  8: '1',
  9: '2',
  10: '3',
  11: '4',
  12: '5',
  13: '6',
  14: '7',
  15: '8',
  16: '9',
  29: 'A',
  30: 'B',
  31: 'C',
  32: 'D',
  33: 'E',
  34: 'F',
  35: 'G',
  36: 'H',
  37: 'I',
  38: 'J',
  39: 'K',
  40: 'L',
  41: 'M',
  42: 'N',
  43: 'O',
  44: 'P',
  45: 'Q',
  46: 'R',
  47: 'S',
  48: 'T',
  49: 'U',
  50: 'V',
  51: 'W',
  52: 'X',
  53: 'Y',
  54: 'Z',
  55: ',',
  56: '.',
  69: '-',
  70: '=',
  71: '[',
  72: ']',
  73: '\\',
  74: ';',
  75: "'",
  76: '/',
  81: '+'
}

export function useScannerInput(options = {}) {
  const minLength = Number(options.minLength ?? 3)
  const commitDelay = Number(options.commitDelay ?? 120)
  const uppercase = options.uppercase !== false
  const ignoreInputTarget = options.ignoreInputTarget !== false
  const hideKeyboardOnScan = options.hideKeyboardOnScan !== false
  const hideKeyboardOnLeave = options.hideKeyboardOnLeave !== false
  const onScan = typeof options.onScan === 'function' ? options.onScan : () => {}

  let scannerBuffer = ''
  let scannerTimer = null
  let scannerListening = false
  let plusKeyListening = false

  function getScannerEventTarget() {
    if (typeof document !== 'undefined') return document
    if (typeof window !== 'undefined') return window
    return null
  }

  function registerScannerListener() {
    if (scannerListening) return
    const target = getScannerEventTarget()
    if (target?.addEventListener) {
      target.addEventListener('keydown', handleScannerKeydown)
      scannerListening = true
    }
    registerPlusKeyListener()
  }

  function unregisterScannerListener() {
    const target = getScannerEventTarget()
    if (scannerListening && target?.removeEventListener) {
      target.removeEventListener('keydown', handleScannerKeydown)
    }
    scannerListening = false
    unregisterPlusKeyListener()
    clearScannerBuffer()
    if (hideKeyboardOnLeave) hideSoftKeyboard()
  }

  function registerPlusKeyListener() {
    if (plusKeyListening) return
    if (typeof plus === 'undefined' || !plus?.key?.addEventListener) return
    plus.key.addEventListener('keydown', handlePlusScannerKeydown)
    plusKeyListening = true
  }

  function unregisterPlusKeyListener() {
    if (!plusKeyListening) return
    if (typeof plus !== 'undefined' && plus?.key?.removeEventListener) {
      plus.key.removeEventListener('keydown', handlePlusScannerKeydown)
    }
    plusKeyListening = false
  }

  function handlePlusScannerKeydown(event) {
    handleScannerKeydown({ ...event, isPlusKeyEvent: true })
  }

  function handleScannerKeydown(event) {
    if (ignoreInputTarget) {
      const targetTag = String(event?.target?.tagName || '').toLowerCase()
      if (targetTag === 'input' || targetTag === 'textarea') return
    }

    const key = normalizeScannerKey(event)
    if (!key) return
    if (key === 'Enter') {
      commitScannerBuffer()
      return
    }

    scannerBuffer += key
    if (scannerTimer) clearTimeout(scannerTimer)
    scannerTimer = setTimeout(() => {
      commitScannerBuffer()
    }, commitDelay)
  }

  function normalizeScannerKey(event) {
    if (event?.ctrlKey || event?.altKey || event?.metaKey) return ''
    if (isAndroidPlusKeyEvent(event)) return normalizeAndroidKeyCode(event)

    const key = event?.key
    if (key === 'Enter' || key === 'Tab') return 'Enter'
    if (typeof key === 'string' && key.length === 1) return uppercase ? key.toUpperCase() : key

    const code = Number(event?.keyCode || event?.which || 0)
    if (code === 13 || code === 9) return 'Enter'
    if (code >= 48 && code <= 90) {
      const value = String.fromCharCode(code)
      return uppercase ? value.toUpperCase() : value
    }
    if (code >= 96 && code <= 105) return String(code - 96)
    if (code === 189 || code === 109) return '-'
    if (code === 190 || code === 110) return '.'
    return ''
  }

  function isAndroidPlusKeyEvent(event) {
    return Boolean(event?.isPlusKeyEvent)
  }

  function normalizeAndroidKeyCode(event) {
    const code = Number(event?.keyCode || event?.which || 0)
    if (code === 66 || code === 61 || code === 160) return 'Enter'
    const value = androidKeyCodeMap[code] || ''
    return uppercase ? value.toUpperCase() : value.toLowerCase()
  }

  function clearScannerBuffer() {
    scannerBuffer = ''
    if (scannerTimer) {
      clearTimeout(scannerTimer)
      scannerTimer = null
    }
  }

  async function commitScannerBuffer() {
    const value = scannerBuffer.trim()
    clearScannerBuffer()
    if (value.length < minLength) return
    if (hideKeyboardOnScan) hideSoftKeyboard()
    await onScan(value)
  }

  function hideSoftKeyboard() {
    try {
      uni.hideKeyboard()
    } catch (e) {}
  }

  onShow(() => {
    registerScannerListener()
  })

  onHide(() => {
    unregisterScannerListener()
  })

  onUnload(() => {
    unregisterScannerListener()
  })

  return {
    clearScannerBuffer,
    registerScannerListener,
    unregisterScannerListener
  }
}