package com.barcodescanner

import android.Manifest
import android.content.Context
import android.graphics.Canvas
import android.graphics.Color
import android.util.AttributeSet
import android.util.Log
import android.view.Choreographer
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import com.google.zxing.MultiFormatReader
import com.google.zxing.Result
import me.dm7.barcodescanner.core.IViewFinder
import me.dm7.barcodescanner.zxing.ZXingScannerView


class BarcodeScannerView : ZXingScannerView, ZXingScannerView.ResultHandler {
  constructor(context: Context?) : super(context)
  constructor(context: Context?, attrs: AttributeSet?) : super(context, attrs)

  private val callBacks = mutableListOf<CallBack>()
  private var flashEnabled: Boolean = false
  private var autoFocusEnabled: Boolean = false
  private var isCameraStarted: Boolean = false
  private var viewFinder: BarcodeViewFinder? = null
  private var frameWidth: Int? = null
  private var frameHeight: Int? = null
  init {
    setResultHandler(this)
    // relate to react native issue https://github.com/facebook/react-native/issues/17968
    setupLayoutHack()
    setIsBorderCornerRounded(true)
    setBorderCornerRadius(10)
  }

  override fun createViewFinderView(context: Context): IViewFinder {
    if (viewFinder == null) {
      viewFinder = BarcodeViewFinder(context)
    }
    return viewFinder!!
  }

  fun setFrameWidth(width: Int) {
    frameWidth = width
    viewFinder?.layoutParams?.run {
      viewFinder?.layoutParams = ViewGroup.LayoutParams(width, frameHeight ?: this.height)
    }
    viewFinder?.setFrameWidth(width)
  }

  fun setFrameHeight(height: Int) {
    frameHeight = height
    viewFinder?.layoutParams?.run {
      viewFinder?.layoutParams = ViewGroup.LayoutParams(frameWidth ?: this.width, height)
    }
    viewFinder?.setFrameHeight(height)
  }

  private fun setupLayoutHack() {
    Choreographer.getInstance().postFrameCallback(object : Choreographer.FrameCallback {
      override fun doFrame(frameTimeNanos: Long) {
        manuallyLayoutChildren()
        viewTreeObserver.dispatchOnGlobalLayout()
        Choreographer.getInstance().postFrameCallback(this)
      }
    })
  }

  fun manuallyLayoutChildren() {
    for (i in 0 until childCount) {
      val child = getChildAt(i)
      child.measure(
        MeasureSpec.makeMeasureSpec(measuredWidth, MeasureSpec.EXACTLY),
        MeasureSpec.makeMeasureSpec(measuredHeight, MeasureSpec.EXACTLY)
      )
      child.layout(0, 0, child.measuredWidth, child.measuredHeight)
    }
  }

  fun setFlashModeEnabled(enabled: Boolean) {
    flashEnabled = enabled
    if (isCameraStarted) {
      flash = enabled
    }
  }

  fun setAutoFocusEnabled(enabled: Boolean) {
    autoFocusEnabled = enabled
    if (isCameraStarted) {
      setAutoFocus(enabled)
    }
  }

  fun setOnResultListener(callBack: (String) -> Unit) {
    if (!callBacks.contains(callBack)) {
      callBacks.add(callBack)
    }
  }

  override fun handleResult(rawResult: Result?) {
    val scanResult = rawResult?.text
    if (scanResult != null) {
      callBacks.onEach {
        it.invoke(scanResult)
      }
    }
    resumeCameraPreview(this)
  }

  override fun onDetachedFromWindow() {
    super.onDetachedFromWindow()
    callBacks.clear()
    isCameraStarted = false
  }

  fun startCameraPreview() {
    if (hasCameraPermission() && !isCameraStarted) {
      setResultHandler(this)
      isCameraStarted = true
      startCamera()
      flash = flashEnabled
      setAutoFocus(autoFocusEnabled)
    }
  }

  override fun stopCamera() {
    super.stopCamera()
    isCameraStarted = false
  }

  private fun hasCameraPermission(): Boolean =
    context.isPermissionAlreadyPermit(Manifest.permission.CAMERA)
}