/** Data structure representing a single steering command.
 * <p>
 * This version only supports ongoing steering, not recurring steering. 
 * To perform one-time-only steering, set startTime = stopTime.
 * <p>
 * This version only supports fixed-value steering (set X = 3), nothing fancier
 * (set X = X+1 or set X = Y) yet.
 *
 * @version 0.2
 * @author Glenn Matthews
 */
public class SteerNode implements Comparable<SteerNode> {

/** The simulation time at which this steering command becomes relevant. */
double startTime;

/** The simulation time after which this steering command becomes irrelevant
 * and should be discarded. */
double stopTime;

/** The identifier of the variable to be steered. */
String targetVar;

/** The value to which the variable should be set. */
String setPoint;

/** The identifier of the steering app that asked for this control. */
int clientID;

/** Basic constructor. */
public SteerNode(double start, double stop, String target, 
			String set, int client)
{
	startTime = start;
	stopTime = stop;
	targetVar = target;
	setPoint = set;
	clientID = client;
} //constructor

/** More future-compatible constructor. Parses a String to determine parameters
 * @param client Identifier of the client app making this request.
 * @param attribs String of the format "{@link #targetVar}\r\n{@link
 * #setPoint}\r\n{@link #startTime}\r\n{@link #stopTime}"
 */
public SteerNode(int client, String attribs)
{
	clientID = client;
	//String[] s = attribs.split("\r\n");
	String[] s = attribs.split("\t");
	targetVar = s[0];
	setPoint = s[1];
	startTime = Double.parseDouble(s[2]);
	stopTime = Double.parseDouble(s[3]);
}//constructor

/* GETTERS */
public int getClientID() { return clientID; }
public double getStartTime() { return startTime; }
public double getStopTime() { return stopTime; }
public String getTargetVar() { return targetVar; }
public String getSetPoint() { return setPoint; }
/* SETTERS */
public void setClientID(int i) { clientID = i; }
public void setStartTime(double d) {startTime = d; }
public void setStopTime(double d) { stopTime = d; }
public void setTargetVar(String s) {targetVar = s; }
public void setSetPoint(String s) { setPoint = s; }

/** Compares two SteerNodes. Ordering is as follows:
 * <ol><li>by {@link #startTime}
 * <li>by {@link #stopTime}
 * <li>by {@link #targetVar}
 * <li>by {@link #clientID}
 * </ol>
 * setPoint is not compared; if all other params are equal, the two SteerNodes
 * are in direct conflict, and so should be considered equal!
 */
public int compareTo(SteerNode o)
{
	if (startTime < o.startTime)
		return -1;
	else if (startTime > o.startTime)
		return 1;
	else {
		if (stopTime < o.stopTime)
			return -1;
		else if (stopTime > o.stopTime)
			return 1;
		else {
			int i = targetVar.compareTo(o.targetVar);
			if (i != 0)
				return i;
			if (clientID < o.clientID)
				return -1;
			else if (clientID > o.clientID)
				return 1;
			else
				return 0;
		}
	}
} //compareTo

/** Checks for equality. A SteerNode is never equal to an Object that is not
 * another SteerNode; two SteerNodes are equal if they have equal startTime,
 * stopTime, targetVar, and clientID. Note that two SteerNodes that 
 * have different setPoint values but are otherwise identical are still 
 * considered equal! */
public boolean equals(Object o)
{
	if (!(o instanceof SteerNode))
		return false;
	SteerNode s = (SteerNode)o;
	return (startTime == s.startTime &&
		stopTime == s.stopTime &&
		targetVar.equals(s.targetVar) &&
		clientID == s.clientID);
} // equals()
		
} //SteerNode