/**
* Copyright (C) 2002-2012 The FreeCol Team
*
* This file is part of FreeCol.
*
* FreeCol is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* FreeCol is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with FreeCol. If not, see <http://www.gnu.org/licenses/>.
*/
package net.sf.freecol.server.ai.mission;
import java.util.logging.Logger;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import net.sf.freecol.common.model.Colony;
import net.sf.freecol.common.model.Europe;
import net.sf.freecol.common.model.Location;
import net.sf.freecol.common.model.PathNode;
import net.sf.freecol.common.model.Player;
import net.sf.freecol.common.model.Tile;
import net.sf.freecol.common.model.Unit;
import net.sf.freecol.common.model.pathfinding.CostDecider;
import net.sf.freecol.common.model.pathfinding.CostDeciders;
import net.sf.freecol.common.model.pathfinding.GoalDecider;
import net.sf.freecol.common.model.pathfinding.GoalDeciders;
import net.sf.freecol.server.ai.AIMain;
import net.sf.freecol.server.ai.AIMessage;
import net.sf.freecol.server.ai.AIUnit;
/**
* Mission for cashing in a treasure train.
* TODO: Require protection
* TODO: Better avoidance of enemy units
*/
public class CashInTreasureTrainMission extends Mission {
private static final Logger logger = Logger.getLogger(CashInTreasureTrainMission.class.getName());
private static final String tag = "AI treasureTrain";
/** Maximum number of turns to travel to a cash in location. */
private static final int MAX_TURNS = 20;
/**
* The location to cash this treasure train in at, either a Colony
* or Europe.
*/
private Location target = null;
/**
* Creates a mission for the given <code>AIUnit</code>.
*
* @param aiMain The main AI-object.
* @param aiUnit The <code>AIUnit</code> this mission
* is created for.
*/
public CashInTreasureTrainMission(AIMain aiMain, AIUnit aiUnit) {
super(aiMain, aiUnit);
target = findTarget(aiUnit, true);
logger.finest(tag + " starts at " + aiUnit.getUnit().getLocation()
+ " with target " + target + ": " + this);
uninitialized = false;
}
/**
* Creates a new <code>CashInTreasureTrainMission</code> and reads
* the given element.
*
* @param aiMain The main AI-object.
* @param in The input stream containing the XML.
* @throws XMLStreamException if a problem was encountered
* during parsing.
* @see net.sf.freecol.server.ai.AIObject#readFromXML
*/
public CashInTreasureTrainMission(AIMain aiMain, XMLStreamReader in)
throws XMLStreamException {
super(aiMain);
readFromXML(in);
}
/**
* Sets a new mission target.
*
* @param target The new target <code>Location</code>.
*/
public void setTarget(Location target) {
removeTransportable("retargeted");
this.target = target;
}
/**
* Extract a valid target for this mission from a path.
*
* @param aiUnit A <code>AIUnit</code> to perform the mission.
* @param path A <code>PathNode</code> to extract a target from,
* (uses the unit location if null).
* @return A target for this mission, or null if none found.
*/
public static Location extractTarget(AIUnit aiUnit, PathNode path) {
if (path == null) return null;
final Location loc = path.getLastNode().getLocation();
Colony colony = loc.getColony();
return (loc instanceof Europe
&& invalidReason(aiUnit, loc) == null) ? loc
: (colony != null
&& invalidReason(aiUnit, colony) == null) ? colony
: null;
}
/**
* Evaluate a potential cashin mission for a given unit and
* path.
*
* @param aiUnit The <code>AIUnit</code> to do the mission.
* @param path A <code>PathNode</code> to take to the target.
* @return A score for the proposed mission.
*/
public static int scorePath(AIUnit aiUnit, PathNode path) {
Location loc;
if (path == null
|| (loc = extractTarget(aiUnit, path)) == null
|| !(invalidFullColonyReason(aiUnit, loc.getColony()) == null
|| loc instanceof Europe))
return Integer.MIN_VALUE;
return aiUnit.getUnit().getTreasureAmount() / (path.getTotalTurns()+1);
}
/**
* Makes a goal decider that checks cash in sites.
*
* @param aiUnit The <code>AIUnit</code> to search with.
* @param deferOK Keep track of the nearest colonies to use as a
* fallback destination.
* @return A suitable <code>GoalDecider</code>.
*/
private static GoalDecider getGoalDecider(final AIUnit aiUnit,
final boolean deferOK) {
GoalDecider gd = new GoalDecider() {
private PathNode bestPath = null;
private int bestValue = 0;
public PathNode getGoal() { return bestPath; }
public boolean hasSubGoals() { return true; }
public boolean check(Unit u, PathNode path) {
Location loc = extractTarget(aiUnit, path);
if ((loc instanceof Colony
&& invalidFullColonyReason(aiUnit, (Colony)loc)
== null)
|| loc instanceof Europe) {
int value = scorePath(aiUnit, path);
if (bestValue < value) {
bestValue = value;
bestPath = path;
return true;
}
}
return false;
}
};
return (deferOK) ? GoalDeciders.getComposedGoalDecider(gd,
GoalDeciders.getOurClosestSettlementGoalDecider())
: gd;
}
/**
* Find a suitable cash in location for this unit.
*
* @param aiUnit The <code>AIUnit</code> to execute a cash in mission.
* @param deferOK Enables deferring to a fallback colony.
* @return A <code>PathNode</code> to the target, or null if not found
* which includes the case when Europe should be preferred (because
* the unit can not get there by itself).
*/
private static PathNode findTargetPath(AIUnit aiUnit, boolean deferOK) {
if (invalidAIUnitReason(aiUnit) != null) return null;
final Unit unit = aiUnit.getUnit();
final Tile startTile = unit.getPathStartTile();
if (startTile == null) return null;
// Not on the map? Europe *must* be viable, so go there
// (return null for now, path still impossible).
PathNode path;
final Player player = unit.getOwner();
final Europe europe = player.getEurope();
final Unit carrier = unit.getCarrier();
final CostDecider standardCd
= CostDeciders.avoidSettlementsAndBlockingUnits();
final CostDecider relaxedCd = CostDeciders.numberOfTiles();
if (player.getNumberOfSettlements() <= 0) {
// No settlements, so go straight to Europe. If Europe does
// not exist then this mission is doomed. If a carrier is
// present use it, otherwise relax the cost decider and at least
// start working on a path.
return (europe == null)
? null // Nowhere suitable at all!
: (carrier != null)
? unit.findPath(startTile, europe, carrier, standardCd)
: unit.findPath(startTile, europe, null, relaxedCd);
}
// Can the unit get to a cash in site?
final GoalDecider gd = getGoalDecider(aiUnit, deferOK);
path = unit.search(startTile, gd, standardCd, MAX_TURNS, carrier);
if (path != null) return path;
// One more try with a relaxed cost decider and no range limit.
return unit.search(startTile, gd, relaxedCd, INFINITY, carrier);
}
/**
* Finds a suitable cashin target for the supplied unit.
*
* @param aiUnit The <code>AIUnit</code> to test.
* @param deferOK Enables deferring to a fallback colony.
* @return A <code>PathNode</code> to the target, or null if none found.
*/
public static Location findTarget(AIUnit aiUnit, boolean deferOK) {
final Player player = aiUnit.getUnit().getOwner();
PathNode path = findTargetPath(aiUnit, deferOK);
return (path != null) ? extractTarget(aiUnit, path)
: null;
}
// Fake Transportable interface
/**
* Gets the transport destination for units with this mission.
*
* @return The destination for this <code>Transportable</code>.
*/
@Override
public Location getTransportDestination() {
return (target instanceof Europe
|| (target instanceof Colony
&& shouldTakeTransportToTile(target.getTile()))) ? target
: null;
}
/**
* Gets the priority of getting the unit to the transport
* destination.
*
* @return The priority.
*/
public int getTransportPriority() {
return (getTransportDestination() == null) ? 0
: getUnit().getTreasureAmount();
}
// Mission interface
/**
* Gets the location we are aiming to cash in at.
*
* @return The location we are aiming to cash in at.
*/
public Location getTarget() {
return target;
}
/**
* Why would this mission be invalid with the given unit?
*
* @param aiUnit The <code>AIUnit</code> to test.
* @return A reason why the mission would be invalid with the unit,
* or null if none found.
*/
private static String invalidMissionReason(AIUnit aiUnit) {
String reason = invalidAIUnitReason(aiUnit);
if (reason != null) return reason;
final Unit unit = aiUnit.getUnit();
return (!unit.canCarryTreasure()) ? "unit-cannot-carry-treasure"
: (unit.getTreasureAmount() <= 0) ? "unit-treasure-nonpositive"
: null;
}
/**
* Why is this mission invalid with a given colony target, given that
* intermediate colonies are excluded.
*
* @param aiUnit The <code>AIUnit</code> to check.
* @param colony The potential target <code>Colony</code>.
* @return A reason for mission invalidity, or null if none found.
*/
private static String invalidFullColonyReason(AIUnit aiUnit,
Colony colony) {
String reason = invalidTargetReason(colony,
aiUnit.getUnit().getOwner());
return (reason != null)
? reason
: (!aiUnit.getUnit().canCashInTreasureTrain(colony.getTile()))
? "cashin-impossible-at-location"
: null;
}
/**
* Why is this mission invalid with a given colony target, given that
* intermediate colonies are included.
*
* @param aiUnit The <code>AIUnit</code> to check.
* @param colony The potential target <code>Colony</code>.
* @return A reason for mission invalidity, or null if none found.
*/
private static String invalidColonyReason(AIUnit aiUnit, Colony colony) {
return invalidTargetReason(colony, aiUnit.getUnit().getOwner());
}
/**
* Why is this mission invalid with a given Europe target?
*
* @param aiUnit The <code>AIUnit</code> to check.
* @param europe The potential target <code>Europe</code>.
* @return A reason for mission invalidity, or null if none found.
*/
private static String invalidEuropeReason(AIUnit aiUnit, Europe europe) {
return invalidTargetReason(europe, aiUnit.getUnit().getOwner());
}
/**
* Why is this mission invalid?
*
* @return A reason for mission invalidity, or null if none found.
*/
public String invalidReason() {
return invalidReason(getAIUnit(), target);
}
/**
* Why would this mission be invalid with the given AI unit?
*
* @param aiUnit The <code>AIUnit</code> to test.
* @return A reason for invalidity, or null if none found.
*/
public static String invalidReason(AIUnit aiUnit) {
return invalidMissionReason(aiUnit);
}
/**
* Why would this mission be invalid with the given AI unit and location?
*
* @param aiUnit The <code>AIUnit</code> to check.
* @param loc The <code>Location</code> to check.
* @return A reason for invalidity, or null if none found.
*/
public static String invalidReason(AIUnit aiUnit, Location loc) {
String reason = invalidMissionReason(aiUnit);
return (reason != null)
? reason
: (loc instanceof Colony)
? invalidColonyReason(aiUnit, (Colony)loc)
: (loc instanceof Europe)
? invalidEuropeReason(aiUnit, (Europe)loc)
: Mission.TARGETINVALID;
}
// Not a one-time mission, omit isOneTime().
/**
* Performs this mission.
*/
public void doMission() {
final Unit unit = getUnit();
String reason = invalidReason();
if (isTargetReason(reason)) {
Location loc = findTarget(getAIUnit(), true);
if (loc == null) {
logger.finest(tag + " could not retarget: " + this);
return;
}
setTarget(loc);
} else if (reason != null) {
logger.finest(tag + " broken(" + reason + "): " + this);
return;
}
// Go to the target.
if (travelToTarget(tag, target,
CostDeciders.avoidSettlementsAndBlockingUnits())
!= Unit.MoveType.MOVE) return;
// Cash in now if:
// - already in Europe
// - or can never get there
// - or there is no potential carrier to get the treasure to there
// - or if the transport fee is not in effect.
// Otherwise, it is better to send to Europe.
final AIUnit aiUnit = getAIUnit();
final Player player = unit.getOwner();
final Europe europe = player.getEurope();
if (unit.canCashInTreasureTrain()) {
if (unit.isInEurope()
|| europe == null
|| Player.getCarriersForUnit(unit).isEmpty()
|| unit.getTransportFee() == 0) {
if (AIMessage.askCashInTreasureTrain(aiUnit)) {
logger.finest(tag + " completed cash in at "
+ unit.getLocation() + ": " + this);
}
} else {
setTarget(europe);
logger.finest(tag + " at " + unit.getLocation()
+ " retargeting Europe: " + this);
}
} else {
Location newTarget = findTarget(aiUnit, false);
logger.finest(tag + " arrived at " + target.getColony().getName()
+ ", retargeting " + newTarget + ": " + this);
setTarget(newTarget);
}
}
// Serialization
/**
* Writes all of the <code>AIObject</code>s and other AI-related
* information to an XML-stream.
*
* @param out The target stream.
* @throws XMLStreamException if there are any problems writing
* to the stream.
*/
protected void toXMLImpl(XMLStreamWriter out) throws XMLStreamException {
if (isValid()) {
toXML(out, getXMLElementTagName());
}
}
/**
* {@inheritDoc}
*/
protected void writeAttributes(XMLStreamWriter out)
throws XMLStreamException {
super.writeAttributes(out);
if (target != null) {
out.writeAttribute("target", target.getId());
}
}
/**
* {@inheritDoc}
*/
protected void readAttributes(XMLStreamReader in)
throws XMLStreamException {
super.readAttributes(in);
String str = in.getAttributeValue(null, "target");
target = getGame().getFreeColLocation(str);
}
/**
* Returns the tag name of the root element representing this object.
*
* @return "cashInTreasureTrainMission".
*/
public static String getXMLElementTagName() {
return "cashInTreasureTrainMission";
}
}