import android.graphics.ImageFormat.*
import android.os.Build
import android.util.Log
import androidx.camera.core.ImageAnalysis
import androidx.camera.core.ImageProxy
import com.google.zxing.*
import com.google.zxing.common.HybridBinarizer
import java.nio.ByteBuffer

private fun ByteBuffer.toByteArray(): ByteArray {
    rewind()
    val data = ByteArray(remaining())
    get(data)
    return data
}

class QrCodeAnalyzer(
    private val onQrCodesDetected: (qrCode: Result) -> Unit
) : ImageAnalysis.Analyzer {

    private val yuvFormats = mutableListOf(YUV_420_888)
    private val tag = "QrCodeAnalyzer"

    init {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            yuvFormats.addAll(listOf(YUV_422_888, YUV_444_888))
        }
    }

    private val reader = MultiFormatReader().apply {
        val map = mapOf(
            DecodeHintType.POSSIBLE_FORMATS to arrayListOf(BarcodeFormat.QR_CODE)
        )
        setHints(map)
    }

    override fun analyze(image: ImageProxy) {
        if (image.format !in yuvFormats) {
            Log.e(tag, "Expected yuv, but format is ${image.format}")
            return
        }

        val byteArray = image.planes[0].buffer.toByteArray()

        val source = PlanarYUVLuminanceSource(
                byteArray,
                image.width,
                image.height,
                0,
                0,
                image.width,
                image.height,
                false
        )

        val binaryBitmap = BinaryBitmap(HybridBinarizer(source))
        try {
            val result = reader.decode(binaryBitmap)
            onQrCodesDetected(result)
        } catch (e: NotFoundException) {
            e.printStackTrace()
        }
        image.close()
    }
}