/**
* 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.ArrayList;
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.EquipmentType;
import net.sf.freecol.common.model.FreeColGameObject;
import net.sf.freecol.common.model.IndianSettlement;
import net.sf.freecol.common.model.Location;
import net.sf.freecol.common.model.Map.Direction;
import net.sf.freecol.common.model.PathNode;
import net.sf.freecol.common.model.Player;
import net.sf.freecol.common.model.Settlement;
import net.sf.freecol.common.model.Tension;
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 controlling a scout.
*/
public class ScoutingMission extends Mission {
private static final Logger logger = Logger.getLogger(ScoutingMission.class.getName());
private static final String tag = "AI scout";
/**
* Maximum number of turns to travel to a scouting target.
*/
private static final int MAX_TURNS = 20;
/**
* The target for this mission. Either a tile with an LCR, a
* native settlement to talk to the chief of, or a player colony
* to retarget from.
*/
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 ScoutingMission(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>ScoutingMission</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 ScoutingMission(AIMain aiMain, XMLStreamReader in)
throws XMLStreamException {
super(aiMain);
readFromXML(in);
uninitialized = getAIUnit() == null;
}
/**
* 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();
return (loc == null) ? null
: (invalidSettlementReason(aiUnit, loc.getSettlement()) == null)
? loc.getSettlement()
: (invalidTileReason(aiUnit, loc.getTile()) == null)
? loc.getTile()
: null;
}
/**
* Gets a <code>GoalDecider</code> for finding the best colony
* <code>Tile</code>, optionally falling back to the nearest colony.
*
* @param aiUnit The <code>AIUnit</code> that is searching.
* @param deferOK Enable colony fallback.
* @return A suitable <code>GoalDecider</code>.
*/
private static GoalDecider getGoalDecider(final AIUnit aiUnit,
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 IndianSettlement
|| loc instanceof Tile) {
int value = scorePath(aiUnit, path);
if (bestValue < value) {
bestValue = value;
bestPath = path;
return true;
}
}
return false;
}
};
return (deferOK) ? GoalDeciders.getComposedGoalDecider(gd,
GoalDeciders.getOurClosestSettlementGoalDecider())
: gd;
}
/**
* Evaluate a potential scouting 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
|| !(loc instanceof IndianSettlement || loc instanceof Tile))
return Integer.MIN_VALUE;
return 1000 / (path.getTotalTurns() + 1);
}
/**
* Finds a suitable scouting target for the supplied unit.
*
* @param deferOK If true, allow the search to return a nearby existing
* colony as a temporary target.
* @return A path to the new colony or backup.
*/
public 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;
PathNode path;
final Unit carrier = unit.getCarrier();
final GoalDecider gd = getGoalDecider(aiUnit, deferOK);
final CostDecider standardCd = CostDeciders.avoidIllegal();
final CostDecider relaxedCd = CostDeciders.numberOfTiles();
// Can the scout legally reach a valid target from where it
// currently is?
path = unit.search(startTile, gd, standardCd, MAX_TURNS, carrier);
if (path != null) return path;
// Search again, purely on distance in tiles, which allows
// water tiles and thus potentially finds targets that require
// a carrier to reach.
return unit.search(startTile, gd, relaxedCd, INFINITY, carrier);
}
/**
* Finds a suitable scouting target for the supplied unit.
* Falls back to the best settlement if a path is not found.
*
* TODO: improve the fallback to an actual scouting target.
*
* @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) {
PathNode path = findTargetPath(aiUnit, deferOK);
return (path != null) ? extractTarget(aiUnit, path)
: (deferOK) ? getBestSettlement(aiUnit.getUnit().getOwner())
: 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 (getTarget() == null
|| !shouldTakeTransportToTile(getTarget().getTile())) ? null
: target;
}
// Mission interface
/**
* Gets the target for this mission.
*
* @return The mission target.
*/
public Location getTarget() {
return target;
}
/**
* Why would this mission be invalid with the given unit.
*
* @param aiUnit The <code>AIUnit</code> to check.
* @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);
return (reason != null)
? reason
: (!aiUnit.getUnit().hasAbility("model.ability.scoutIndianSettlement"))
? "unit-not-a-SCOUT"
: null;
}
/**
* Why is this mission invalid with a given colony target?
*
* @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 native settlement target?
*
* @param aiUnit The <code>AIUnit</code> to check.
* @param is The potential target <code>IndianSettlement</code>.
* @return A reason for mission invalidity, or null if none found.
*/
private static String invalidIndianSettlementReason(AIUnit aiUnit,
IndianSettlement is) {
final Unit unit = aiUnit.getUnit();
final Player owner = unit.getOwner();
Tension tension;
String reason = invalidTargetReason(is);
return (reason != null) ? reason
: (is.hasSpokenToChief(owner))
? "settlement-contacted"
: ((tension = is.getAlarm(owner)) != null
&& tension.getValue() >= Tension.Level.HATEFUL.getLimit())
? "settlement-hateful"
: null;
}
/**
* Is this a valid scouting target because it is a suitable native
* settlement or an intermediate colony.
*
* @param aiUnit The <code>AIUnit</code> to test.
* @param settlement The <code>Settlement</code> to test.
* @return A reason why the mission would be invalid, or null if none found.
*/
private static String invalidSettlementReason(AIUnit aiUnit,
Settlement settlement) {
return (settlement instanceof Colony)
? invalidColonyReason(aiUnit, (Colony)settlement)
: (settlement instanceof IndianSettlement)
? invalidIndianSettlementReason(aiUnit, (IndianSettlement)settlement)
: Mission.TARGETINVALID;
}
/**
* Is this a valid scouting target because it is a suitable tile.
*
* @param aiUnit The <code>AIUnit</code> to test.
* @param is The <code>IndianSettlement</code> to test.
* @return A reason why the mission would be invalid, or null if none found.
*/
private static String invalidTileReason(AIUnit aiUnit, Tile tile) {
return (tile == null) ? "tile-null"
: (!tile.hasLostCityRumour()) ? "tile-lacks-rumour"
: null;
}
/**
* Why is this mission invalid?
*
* @return A reason for mission invalidity, or null if none found.
*/
public String invalidReason() {
return invalidReason(getAIUnit(), getTarget());
}
/**
* Why would this mission be invalid with the given AI unit?
*
* @param aiUnit The <code>AIUnit</code> to check.
* @return A reason for mission 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 Settlement)
? invalidSettlementReason(aiUnit, (Settlement)loc)
: (loc instanceof Tile)
? invalidTileReason(aiUnit, (Tile)loc)
: Mission.TARGETINVALID;
}
// Not a one-time mission, omit isOneTime().
/**
* Performs this mission.
*/
public void doMission() {
final AIUnit aiUnit = getAIUnit();
String reason = invalidReason();
if (isTargetReason(reason)) {
Location loc = findTarget(aiUnit, 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.
final Unit unit = getUnit();
Direction d;
Unit.MoveType mt = travelToTarget(tag, getTarget(),
CostDeciders.avoidSettlementsAndBlockingUnits());
switch (mt) {
case MOVE_ILLEGAL: case MOVE_NO_MOVES: case MOVE_NO_REPAIR:
return;
case ATTACK_UNIT:
// Could be adjacent to the destination but it is
// temporarily blocked by another unit. Make a random
// (directed if possible) move and try again.
moveRandomly(tag, unit.getTile()
.getDirection(getTarget().getTile()));
return;
case MOVE:
break;
case ENTER_INDIAN_SETTLEMENT_WITH_SCOUT:
if ((d = unit.getTile()
.getDirection(getTarget().getTile())) == null) {
throw new IllegalStateException("Unit not next to target "
+ getTarget() + ": " + unit + "/" + unit.getLocation());
}
if (!AIMessage.askScoutIndianSettlement(aiUnit, d)) {
logger.warning(tag + " unexpected failure at " + getTarget()
+ ": " + this);
}
break;
case EXPLORE_LOST_CITY_RUMOUR:
if ((d = unit.getTile()
.getDirection(getTarget().getTile())) == null) {
throw new IllegalStateException("Unit not next to target "
+ getTarget() + ": " + unit + "/" + unit.getLocation());
}
if (!AIMessage.askMove(aiUnit, d)) {
logger.warning(tag + " unexpected failure at " + getTarget()
+ ": " + this);
}
break;
default:
logger.warning(tag + " unexpected move type " + mt + ": " + this);
return;
}
if (unit.isDisposed()) {
logger.finest(tag + " died at target " + getTarget() + ": " + this);
return;
}
// Retarget on failure or complete, but do not retarget from
// one colony to another, just drop equipment and invalidate
// the mission.
Location completed = getTarget();
setTarget(findTarget(aiUnit, false));
if (completed instanceof Colony) {
if (getTarget() == null) {
for (EquipmentType e : new ArrayList<EquipmentType>(unit
.getEquipment().keySet())) {
AIMessage.askEquipUnit(aiUnit, e, -unit.getEquipmentCount(e));
}
}
logger.finest(tag + " arrived at " + ((Colony)completed).getName()
+ ", retargeting " + getTarget() + ": " + this);
} else {
logger.finest(tag + " completed target " + completed
+ ", retargeting " + getTarget() + ": " + this);
}
}
// 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) {
writeAttribute(out, "target", (FreeColGameObject)target);
}
}
/**
* {@inheritDoc}
*/
protected void readAttributes(XMLStreamReader in)
throws XMLStreamException {
super.readAttributes(in);
String str = in.getAttributeValue(null, "target");
target = (str == null) ? null : getGame().getFreeColLocation(str);
}
/**
* Returns the tag name of the root element representing this object.
*
* @return "scoutingMission".
*/
public static String getXMLElementTagName() {
return "scoutingMission";
}
}