package rep;

import java.util.LinkedList;

import rep.channel.REPSocketChannel;
import rep.handler.REPNode;
import rep.handler.NullForwarder;

public class SessionManagerList extends LinkedList<REPNode>{

	/**
	 * Session Manager List which we have a connection.
	 */
	private static final long serialVersionUID = 1L;
	private int mySMID=0;
	private int smid_root=0;
	private REPNode parent=new NullForwarder(null,null);
	private LinkedList<REPNode> waiting= new LinkedList<REPNode>();


	public void setMaster(REPNode f) {
		this.parent = f;
	}

	public void sendToMaster(REPCommand repCmd) {
		parent.send(repCmd);
	}

	public void sendToSlaves(REPCommand repCmd) {
		for(REPNode channel : this){
			channel.send(repCmd);
		}
	}

	public boolean isMaster() {
		return !parent.isForwarder();
	}

	/**
	 * Add our slave session manager. Only an empty session manager can
	 * connect to the other session manager. join_sm() is forwarded to
	 * the master session manager, and in the master addNewSessionManager()
	 * is performed.
	 * 
	 * @param sm
	 * @param receivedCommand
	 * @return session manager id (global)
	 */
	public int addNewSessionManager(REPNode sm,REPCommand receivedCommand) {
		add(sm);
		int sid = ++smid_root;
		sm.setSID(sid);
		sm.setName(receivedCommand.string);
		return sid;
	}


	public void setSessionManagerID(int sid) {
		mySMID = sid;
	}
	
	public int sessionManagerID() {
		return mySMID;
	}

	/**
	 * An sm_join() is accepted, but we are not the master, forward request
	 * and register as an waiting sessin manager.
	 * @param fw
	 * @param command
	 */
	public void addWaitingSessionManager(REPNode fw, REPCommand command) {
		// SID assign 待ちのSessionManager Channelを登録する
		waiting.add(fw);
		
	}

	/**
	 * An sm_join_ack() is received. Assign session manager id to the waiter.
	 * @param sid
	 */
	public void assignSessionManagerIDtoWaitingSM(int sid) {
		// 待っていたSession Manager ChannelにSession IDを登録し，Session Manager List
		// に登録する。この次のsm_join_ackでSIDが確定する。
		REPNode waiter;
		if ((waiter=waiting.poll())!=null) {
			waiter.setSID(sid);
			add(waiter);
			return;
		}
		assert false;
	}

	public void setParent(REPNode fw) {
		parent = fw;
	}
	
	public REPNode parent() {
		return parent;
	}

	public REPNode managerByChannel(REPSocketChannel<REPCommand> channel) {
		for(REPNode e:this) {
			if (e.channel==channel)
				return e;
		}
		return null;
	}

}