michas-droid/src/main/kotlin/nya/kitsunyan/foxydroid/utility/extension/Text.kt

@file:Suppress("PackageDirectoryMismatch")
package nya.kitsunyan.foxydroid.utility.extension.text

import android.util.Log
import java.util.Locale

fun <T: CharSequence> T.nullIfEmpty(): T? {
  return if (isNullOrEmpty()) null else this
}

private val sizeFormats = listOf("%.0f B", "%.0f kB", "%.1f MB", "%.2f GB")

fun Long.formatSize(): String {
  val (size, index) = generateSequence(Pair(this.toFloat(), 0)) { (size, index) -> if (size >= 1000f)
    Pair(size / 1000f, index + 1) else null }.take(sizeFormats.size).last()
  return sizeFormats[index].format(Locale.US, size)
}

fun Char.halfByte(): Int {
  return when (this) {
    in '0' .. '9' -> this - '0'
    in 'a' .. 'f' -> this - 'a' + 10
    in 'A' .. 'F' -> this - 'A' + 10
    else -> -1
  }
}

fun CharSequence.unhex(): ByteArray? {
  return if (length % 2 == 0) {
    val ints = windowed(2, 2, false).map {
      val high = it[0].halfByte()
      val low = it[1].halfByte()
      if (high >= 0 && low >= 0) {
        (high shl 4) or low
      } else {
        -1
      }
    }
    if (ints.any { it < 0 }) null else ints.map { it.toByte() }.toByteArray()
  } else {
    null
  }
}

fun ByteArray.hex(): String {
  val builder = StringBuilder()
  for (byte in this) {
    builder.append("%02x".format(Locale.US, byte.toInt() and 0xff))
  }
  return builder.toString()
}

fun Any.debug(message: String) {
  val tag = this::class.java.name.let {
    val index = it.lastIndexOf('.')
    if (index >= 0) it.substring(index + 1) else it
  }.replace('$', '.')
  Log.d(tag, message)
}