import java.lang.reflect.Type;
import java.util.Comparator;
import java.util.Iterator;


/**
 * This class lets you take a class which derives from IAgent and wrap
 * it as a TreeAlgAgent, so you can use it with the tree-based
 * connectivity maintenance algorithm.
 * It automatically makes the "parent preference relation" into
 * "prefer nodes which are closer to you".
 * @author mds
 *
 * @param <TAgent> This is the type of the agent it wraps.  I think
 * everything should be okay if you don't supply it (thus making it default to
 * IAgent), but if you need to access class-specific member functions for whatever
 * agent you pass, the TAgent class helps alleviate unneccessary casting.
 */
public class TreeAlgAgentAdapter<TAgent extends IAgent> implements ITreeAlgAgent {

	TAgent m_agent;

	public TreeAlgAgentAdapter(TAgent agentToWrap) {
		m_agent = agentToWrap;
	}
	
	public TAgent accessAgent() {
		return m_agent;
	}
	
	public TreeAlgAgentAdapter(TreeAlgAgentAdapter<TAgent> src) {
		m_agent = (TAgent)(src.m_agent.makeCopy());
	}
    
	public IMsg getMsgAnnotation(ILogicVarBundle vars,
			double [] arrLfState, int nIdx) {
		return new AgentMsgHelpers.PosMsg(arrLfState,
				nIdx*2, 2);
	}
	
	public java.lang.reflect.Type getAnnoteType() {
		return AgentMsgHelpers.PosMsg.class;
	}
		
	
	class lclCompare implements java.util.Comparator<TreeConstraintState> {
		
		TreeConstraintState m_agentSorting;
		AgentMsgHelpers.PosMsg m_posMsg;
		
		public lclCompare(TreeConstraintState agentSorting)
		{ 
			m_agentSorting = agentSorting;
			m_posMsg = (AgentMsgHelpers.PosMsg)
			 (m_agentSorting.getMsgAddition(AgentMsgHelpers.PosMsg.class));
		}
		
		/**
		 * smaller number means more preference.
		 */
		public int compare(TreeConstraintState treeState1, 
				TreeConstraintState treeState2) {
			IMsg attach1 = treeState1.getMsgAddition(AgentMsgHelpers.PosMsg.class);
			IMsg attach2 = treeState2.getMsgAddition(AgentMsgHelpers.PosMsg.class);
			
			// prefer to attach to things other than yourself
			if(treeState1.getId() == m_agentSorting.getId() &&
		  			treeState2.getId() != m_agentSorting.getId()) {
		  		return 1;
		  	} else if(treeState2.getId() == m_agentSorting.getId() &&
		  			treeState1.getId() != m_agentSorting.getId()) {
		  		return -1;
		  	}
			
			if(treeState1.getRootId() >= 0 && 
					treeState1.getRootId() < treeState2.getRootId()) {
				return -1;
			}
			
			if(treeState2.getRootId() >= 0 && 
					treeState2.getRootId() < treeState1.getRootId()) {
				return 1;
			}
			
			try {
				AgentMsgHelpers.PosMsg pos1 = 
					(AgentMsgHelpers.PosMsg) attach1;
				AgentMsgHelpers.PosMsg pos2 = 
					(AgentMsgHelpers.PosMsg) attach2;
			
				double lfDist1Sqrd = m_posMsg.getDistSqrd(pos1);
				double lfDist2Sqrd = m_posMsg.getDistSqrd(pos2);
				if(lfDist1Sqrd < lfDist2Sqrd) {
					return -1;
				}
				if(lfDist1Sqrd > lfDist2Sqrd) {
					return 1;
				}
			} catch(Exception e) {
			  	
			}
			if(treeState1.getId() == m_agentSorting.getParentId() &&
					treeState2.getId() != m_agentSorting.getParentId()) {
				return -1;
			}
			if(treeState2.getId() == m_agentSorting.getParentId() &&
					treeState1.getId() != m_agentSorting.getParentId()) {
				return 1;
			}
			return 0; // equality if all else fails
		}
	}
	
	/**
	 * gets a comparator for sorting ITreeAlgAgent nodes by preference
	 * @return Comparator -- smaller number means more preference
	 */
	public java.util.Comparator<TreeConstraintState> 
		getPrefComp(TreeConstraintState agentSorting) {
		
		return new lclCompare(agentSorting);
	}


	public ITreeAlgAgent makeCopy() {
		// TODO Auto-generated method stub
		return new TreeAlgAgentAdapter<TAgent>(this);
	}

	public boolean checkStateValidity(StateBundle state) {
		return m_agent.checkStateValidity(state);
	}

	public void getMsgs(ILogicVarBundle discreteState,
			IDiscreteDynamicsCallback dynCallback, double[] arrLfStateCont,
			double lfCurrTime, int nIdxStateOffset,
			Iterator<CommLink> channelsToSendOn) {
		m_agent.getMsgs(discreteState, dynCallback, arrLfStateCont, lfCurrTime, nIdxStateOffset, channelsToSendOn);
	}

	public StateBundle updateState(ILogicVarBundle statePrev,
			double[] arrLfStateCont, double lfCurrTime, int nIdxStateOffset,
			IEnvironment env, Iterator<CommLink> channelsRecieveFrom) {
		return m_agent.updateState(statePrev, arrLfStateCont, lfCurrTime, nIdxStateOffset, env, channelsRecieveFrom);
	}

}