package be.mygod.vpnhotspot.util

import android.graphics.Bitmap
import android.graphics.Color
import android.os.Bundle
import android.view.LayoutInflater
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.Toast
import androidx.core.os.bundleOf
import androidx.fragment.app.DialogFragment
import be.mygod.vpnhotspot.R
import com.google.zxing.BarcodeFormat
import com.google.zxing.EncodeHintType
import com.google.zxing.MultiFormatWriter
import com.google.zxing.WriterException
import timber.log.Timber
import java.nio.charset.StandardCharsets

class QRCodeDialog : DialogFragment() {
    companion object {
        private const val KEY_ARG = "arg"
        private val iso88591 = StandardCharsets.ISO_8859_1.newEncoder()
    }

    fun withArg(arg: String) = apply { arguments = bundleOf(KEY_ARG to arg) }
    private val arg get() = arguments?.getString(KEY_ARG)

    /**
     * Based on:
     * https://android.googlesource.com/platform/packages/apps/Settings/+/0d706f0/src/com/android/settings/wifi/qrcode/QrCodeGenerator.java
     * https://android.googlesource.com/platform/packages/apps/Settings/+/8a9ccfd/src/com/android/settings/wifi/dpp/WifiDppQrCodeGeneratorFragment.java#153
     */
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?) = try {
        val size = resources.getDimensionPixelSize(R.dimen.qrcode_size)
        val hints = mutableMapOf<EncodeHintType, Any>()
        if (!iso88591.canEncode(arg)) hints[EncodeHintType.CHARACTER_SET] = StandardCharsets.UTF_8.name()
        val qrBits = MultiFormatWriter().encode(arg, BarcodeFormat.QR_CODE, size, size, hints)
        ImageView(context).apply {
            layoutParams = ViewGroup.LayoutParams(size, size)
            setImageBitmap(Bitmap.createBitmap(size, size, Bitmap.Config.RGB_565).apply {
                for (x in 0 until size) for (y in 0 until size) {
                    setPixel(x, y, if (qrBits.get(x, y)) Color.BLACK else Color.WHITE)
                }
            })
        }
    } catch (e: WriterException) {
        Timber.w(e)
        Toast.makeText(context, e.readableMessage, Toast.LENGTH_LONG).show()
        dismiss()
        null
    }
}