package net.cakenet.rsps.component;

import net.cakenet.rsps.Stream;

/**
 * The @code ComponentManager} is used to create resources on the fly for reusable components and then hold them when
 * they're finished with so that they can be reused later
 *
 * @author James Lawrence
 * @version 1
 */
public final class ComponentManager {
    private static ComponentList<Stream> streamComponents;

    static {
        streamComponents = new ComponentList<Stream>();
    }

    private ComponentManager() {}

    /**
     * Retrieves a stream object with the specified length from the component manager, or creates one if needed.
     * After the stream has been acquired by the calling code, it MUST be released by called releaseStream at the end of
     * usage, otherwise memory is being wasted and the object wont be reused!
     * @param length the required buffer length of the stream
     * @return the acquired or created stream object
     */
    public static Stream acquireStream(int length) {
        Stream head = streamComponents.getFirst();
        while(head != null) {
            if(head.capacity == length) {
                // Remove it from the list (acquiring block should re-add it when it's finished)
                head.remove();
                return head;
            } else if(head.capacity > length)
                return new Stream(new byte[length]);
            head = streamComponents.getNext();
        }
        // There wasn't one, create one
        return new Stream(new byte[length]);
    }

    /**
     * Releases the lock from a stream component
     * @param s the stream component to retrieve and unlock
     */
    public static void releaseStream(Stream s) {
        long highId = 0;
        final int searchCapacity = s.capacity;
        Stream head = streamComponents.getFirst();
        while(head != null) {
            if(head.capacity > searchCapacity) {
                // Insert it before this component and return
                streamComponents.addNext(s);
                return;
            }
            head = streamComponents.getNext();
        }
        // Add tail...
        streamComponents.addTail(s);
    }
}