package com.peachpasswords.ui.pairing

import androidx.camera.core.ImageProxy
import com.google.zxing.BinaryBitmap
import com.google.zxing.DecodeHintType
import com.google.zxing.PlanarYUVLuminanceSource
import com.google.zxing.common.GlobalHistogramBinarizer
import com.google.zxing.common.HybridBinarizer
import com.google.zxing.qrcode.QRCodeReader

/** QR-only CameraX decoder for reachability invitations. */
internal object PairingQrFrame {
    fun decode(image: ImageProxy): String? {
        val plane = image.planes.getOrNull(0) ?: return null
        val buffer = plane.buffer
        val data = ByteArray(buffer.remaining())
        buffer.get(data)
        val width = image.width
        val height = image.height
        val luma = if (plane.rowStride == width) {
            data
        } else {
            ByteArray(width * height).also { packed ->
                for (row in 0 until height) {
                    System.arraycopy(
                        data,
                        row * plane.rowStride,
                        packed,
                        row * width,
                        width,
                    )
                }
            }
        }
        val source = PlanarYUVLuminanceSource(
            luma,
            width,
            height,
            0,
            0,
            width,
            height,
            false,
        )
        val hints = mapOf(
            DecodeHintType.TRY_HARDER to true,
            DecodeHintType.POSSIBLE_FORMATS to listOf(com.google.zxing.BarcodeFormat.QR_CODE),
        )
        val attempts = listOf(
            BinaryBitmap(HybridBinarizer(source)),
            BinaryBitmap(GlobalHistogramBinarizer(source)),
            BinaryBitmap(HybridBinarizer(source.rotateCounterClockwise())),
        )
        for (candidate in attempts) {
            try {
                return QRCodeReader().decode(candidate, hints).text
            } catch (_: Exception) {
                // Try the next lighting/orientation strategy.
            }
        }
        return null
    }
}