package pubsub.collection

class BoundedBuffer[T](size: Int) extends AbstractBoundedBuffer[T](size) {

  // You have at your disposition the following two variables:
  // - count : Int
  // - head : Int
  // In addition, you have access to an array-like internal buffer:
  // - buffer
  // You can access elements of this buffer using:
  // - buffer(i)
  // Similarly, you can set elements using:
  // - buffer(i) = e
  //
  // You do not need to create those variables yourself!
  // They are inherited from the AbstractBoundedBuffer class.

  override def put(e: T): Unit = synchronized{
    while(isFull) wait()
    buffer(head) = e
    head = nextHeadIndex;
    count = count + 1;
    notifyAll()
  }

  override def take(): T = synchronized{
    while(isEmpty) wait()

    val e = buffer(tailIndex);
    buffer.delete(tailIndex);
    count = count - 1;
    notifyAll()
    e
  }

  def isEmpty : Boolean = count == 0;
  def isFull : Boolean = count == size
  def tailIndex : Int = {
    val diff = head - count
    if(diff >= 0) diff
    else diff + size
  }
  def nextHeadIndex : Int = (head + 1) % size

  // You may want to add methods to:
  // - check whether the buffer is empty
  // - check whether the buffer is full
  // - get the index of tail
}