package java.io

abstract class InputStream extends Closeable {
  def read(): Int

  def read(b: Array[Byte]): Int = read(b, 0, b.length)

  def read(b: Array[Byte], off: Int, len: Int): Int = {
    if (off < 0 || len < 0 || len > b.length - off)
      throw new IndexOutOfBoundsException

    if (len == 0) 0
    else {
      var bytesWritten = 0
      var next = 0

      while (bytesWritten < len && next != -1) {
        next =
          if (bytesWritten == 0) read()
          else {
            try read()
            catch { case _: IOException => -1 }
          }
        if (next != -1) {
          b(off + bytesWritten) = next.toByte
          bytesWritten += 1
        }
      }

      if (bytesWritten <= 0) -1
      else bytesWritten
    }
  }

  def skip(n: Long): Long = {
    var skipped = 0
    while (skipped < n && read() != -1)
      skipped += 1
    skipped
  }

  def available(): Int = 0

  def close(): Unit = ()

  def mark(readlimit: Int): Unit = ()

  def reset(): Unit =
    throw new IOException("Reset not supported")

  def markSupported(): Boolean = false

}