[fight] #27 Add switch position effects

src/main/java/fr/quatrevieux/araknemu/game/fight/castable/CastScope.java

@@ -93,9 +93,16 @@ public FightCell target() {
 
     /**
      * Get the cast targets
+     *
+     * This method will not resolve target mapping, nor effect target mapping
+     * It will return all targets, before the mapping is resolved
+     * So if {@link CastScope#replaceTarget(PassiveFighter, PassiveFighter)} is called,
+     * the new target will be added on this set
+     *
+     * Note: a new instance is returned to ensure that concurrent modification will not occur
      */
     public Set<PassiveFighter> targets() {
-        return new HashSet<>(targetMapping.values());
+        return new HashSet<>(targetMapping.keySet());
     }
 
     /**
@@ -106,13 +113,23 @@ public Set<PassiveFighter> targets() {
      */
     public void replaceTarget(PassiveFighter originalTarget, PassiveFighter newTarget) {
         targetMapping.put(originalTarget, newTarget);
+
+        // Add new target as target if not yet defined
+        if (!targetMapping.containsKey(newTarget)) {
+            targetMapping.put(newTarget, newTarget);
+        }
     }
 
     /**
      * Remove a target of the cast
+     *
+     * Note: this method will definitively remove the target,
+     * even if {@link CastScope#replaceTarget(PassiveFighter, PassiveFighter)} is called
      */
     public void removeTarget(PassiveFighter target) {
-        targetMapping.remove(target);
+        // Set target to null without remove the key to ensure that it will effectively remove
+        // even if a replaceTarget() point to it
+        targetMapping.put(target, null);
     }
 
     /**
@@ -203,6 +220,40 @@ private Collection<PassiveFighter> resolveTargets(SpellEffect effect) {
         ;
     }
 
+    /**
+     * Resolve the target mapping
+     *
+     * @param baseTarget The base target of the effect
+     *
+     * @return Resolved target. Null if the target is removed
+     */
+    private PassiveFighter resolveTarget(PassiveFighter baseTarget) {
+        PassiveFighter target = targetMapping.get(baseTarget);
+
+        // Target is removed, or it's the original one : do not resolve chaining
+        if (target == null || target.equals(baseTarget)) {
+            return target;
+        }
+
+        // Keep list of visited mapping to break recursion
+        final Set<PassiveFighter> resolved = new HashSet<>();
+
+        resolved.add(baseTarget);
+        resolved.add(target);
+
+        // Resolve chaining
+        for (;;) {
+            target = targetMapping.get(target);
+
+            // The target is removed, or already visited (can be itself)
+            if (target == null || resolved.contains(target)) {
+                return target;
+            }
+
+            resolved.add(target);
+        }
+    }
+
     public final class EffectScope {
         private final SpellEffect effect;
         private final Collection<PassiveFighter> targets;
@@ -224,7 +275,7 @@ public SpellEffect effect() {
          */
         public Collection<PassiveFighter> targets() {
             return targets.stream()
-                .map(targetMapping::get)
+                .map(CastScope.this::resolveTarget)
                 .filter(fighter -> fighter != null && !fighter.dead())
                 .collect(Collectors.toList())
             ;

src/main/java/fr/quatrevieux/araknemu/game/fight/castable/effect/EffectsHandler.java

@@ -23,8 +23,10 @@
 import fr.quatrevieux.araknemu.game.fight.castable.effect.handler.EffectHandler;
 import fr.quatrevieux.araknemu.game.fight.fighter.PassiveFighter;
 
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * Handle fight effects
@@ -40,9 +42,7 @@ public void register(int effectId, EffectHandler applier) {
      * Apply a cast to the fight
      */
     public void apply(CastScope cast) {
-        for (PassiveFighter target : cast.targets()) {
-            target.buffs().onCastTarget(cast);
-        }
+        applyCastTarget(cast);
 
         for (CastScope.EffectScope effect : cast.effects()) {
             // @todo Warning if handler is not found
@@ -57,4 +57,40 @@ public void apply(CastScope cast) {
             }
         }
     }
+
+    /**
+     * Call {@link fr.quatrevieux.araknemu.game.fight.castable.effect.buff.Buffs#onCastTarget(CastScope)}
+     * on each target.
+     *
+     * If a target is changed (by calling {@link CastScope#replaceTarget(PassiveFighter, PassiveFighter)}),
+     * new targets will also be called
+     */
+    private void applyCastTarget(CastScope cast) {
+        Set<PassiveFighter> visitedTargets = Collections.emptySet();
+
+        for (;;) {
+            final Set<PassiveFighter> currentTargets = cast.targets();
+
+            boolean hasChanged = false;
+
+            for (PassiveFighter target : currentTargets) {
+                // Ignore already called targets
+                if (!visitedTargets.contains(target)) {
+                    if (!target.buffs().onCastTarget(cast)) {
+                        // The hook notify a target change
+                        hasChanged = true;
+                    }
+                }
+            }
+
+            // There is no new targets, we can stop here
+            if (!hasChanged) {
+                return;
+            }
+
+            // cast#targets() always contains all resolved targets, including removed ones
+            // so simple change visitedTargets by this value is enough to keep track of all already called fighters
+            visitedTargets = currentTargets;
+        }
+    }
 }

src/main/java/fr/quatrevieux/araknemu/game/fight/castable/effect/buff/BuffHook.java

@@ -22,6 +22,7 @@
 import fr.quatrevieux.araknemu.game.fight.castable.CastScope;
 import fr.quatrevieux.araknemu.game.fight.castable.effect.handler.damage.Damage;
 import fr.quatrevieux.araknemu.game.fight.fighter.ActiveFighter;
+import fr.quatrevieux.araknemu.game.fight.fighter.PassiveFighter;
 
 /**
  * Hook action for apply buff effects
@@ -53,8 +54,59 @@ public default void onBuffTerminated(Buff buff) {}
 
     /**
      * The fighter is a target of a cast
+     *
+     * To get the spell caster, use {@code cast.caster()}, and to get the target, use {@code buff.target()}.
+     *
+     * If the target is changed or removed, this method must return false.
+     * Retuning false permit to notify that the spell targets has changed to ensure that new
+     * target will also be taken in account, but also stop applying other "onCastTarget" hooks
+     * on the current fighter.
+     *
+     * This method will be called on direct and indirect (like spell returned) targets.
+     *
+     * Implementation:
+     * <pre>{@code
+     * class MyEffectHandler implements EffectHandler, BuffHook {
+     *     public void handle(CastScope cast, CastScope.EffectScope effect) {
+     *         // ...
+     *     }
+     *
+     *     // Add the buff to targets
+     *     public void buff(CastScope cast, CastScope.EffectScope effect) {
+     *         for (PassiveFighter target : effect.targets()) {
+     *             target.buffs().add(new Buff(effect.effect(), cast.action(), cast.caster(), target, this));
+     *         }
+     *     }
+     *
+     *     // Implements the buff hook
+     *     public void onCastTarget(Buff buff, CastScope cast) {
+     *         if (!checkCast(cast)) {
+     *             return true; // ignore the hook for this cast : return true to continue on this target
+     *         }
+     *
+     *         // Apply buff effect...
+     *         // ...
+     *
+     *         // Change the target
+     *         // buff.target() is cast target / fighter who has the given buff applied
+     *         cast.replaceTarget(buff.target(), getNewTarget(cast));
+     *
+     *         // You can also remove the current fighter from spell targets
+     *         cast.removeTarget(buff.target());
+     *
+     *         return false; // The target has been changed (or removed)
+     *     }
+     * }
+     * }</pre>
+     *
+     * @return true to continue, or false if the cast target has changed (removed or replaced)
+     *
+     * @see CastScope#removeTarget(PassiveFighter)
+     * @see CastScope#replaceTarget(PassiveFighter, PassiveFighter)
      */
-    public default void onCastTarget(Buff buff, CastScope cast) {}
+    public default boolean onCastTarget(Buff buff, CastScope cast) {
+        return true;
+    }
 
     /**
      * The fighter will take damages

src/main/java/fr/quatrevieux/araknemu/game/fight/castable/effect/buff/BuffList.java

@@ -92,10 +92,14 @@ public void onEndTurn() {
     }
 
     @Override
-    public void onCastTarget(CastScope cast) {
+    public boolean onCastTarget(CastScope cast) {
         for (Buff buff : buffs) {
-            buff.hook().onCastTarget(buff, cast);
+            if (!buff.hook().onCastTarget(buff, cast)) {
+                return false;
+            }
         }
+
+        return true;
     }
 
     @Override

src/main/java/fr/quatrevieux/araknemu/game/fight/castable/effect/buff/Buffs.java

@@ -34,9 +34,16 @@ public interface Buffs extends Iterable<Buff> {
     public void add(Buff buff);
 
     /**
+     * Apply buffs when the fighter is a target of a cast
+     *
+     * If false is returned, the scope targets should be reloaded to call this hook on new targets,
+     * and following hooks will be ignored.
+     *
+     * @return true to continue, or false if the target has changed (or is removed)
+     *
      * @see BuffHook#onCastTarget(Buff, CastScope)
      */
-    public void onCastTarget(CastScope cast);
+    public boolean onCastTarget(CastScope cast);
 
     /**
      * @see BuffHook#onDirectDamage(Buff, ActiveFighter, Damage)

src/main/java/fr/quatrevieux/araknemu/game/fight/castable/effect/handler/armor/SpellReturnHandler.java

@@ -56,20 +56,20 @@ public void buff(CastScope cast, CastScope.EffectScope effect) {
     }
 
     @Override
-    public void onCastTarget(Buff buff, CastScope cast) {
+    public boolean onCastTarget(Buff buff, CastScope cast) {
         if (buff.target().equals(cast.caster()) || !isReturnableCast(cast)) {
-            return;
+            return true;
+        }
+
+        if (!cast.spell().filter(spell -> checkSpellReturned(spell, buff.effect())).isPresent()) {
+            fight.send(ActionEffect.returnSpell(buff.target(), false));
+            return true;
         }
 
-        cast.spell().ifPresent(spell -> {
-            if (!checkSpellReturned(spell, buff.effect())) {
-                fight.send(ActionEffect.returnSpell(buff.target(), false));
-                return;
-            }
+        cast.replaceTarget(buff.target(), cast.caster());
+        fight.send(ActionEffect.returnSpell(buff.target(), true));
 
-            cast.replaceTarget(buff.target(), cast.caster());
-            fight.send(ActionEffect.returnSpell(buff.target(), true));
-        });
+        return false;
     }
 
     /**

src/main/java/fr/quatrevieux/araknemu/game/fight/castable/effect/handler/misc/DispelHandler.java

@@ -48,7 +48,7 @@ public void buff(CastScope cast, EffectScope effect) {
 
     @Override
     public void handle(CastScope cast, EffectScope effect) {
-        for (PassiveFighter fighter : cast.targets()) {
+        for (PassiveFighter fighter : effect.targets()) {
             fighter.buffs().removeAll();
             fight.send(ActionEffect.dispelBuffs(cast.caster(), fighter));
 

src/main/java/fr/quatrevieux/araknemu/game/fight/castable/effect/handler/shifting/AvoidDamageByMovingBackHandler.java

@@ -57,17 +57,19 @@ public void buff(CastScope cast, CastScope.EffectScope effect) {
     }
 
     @Override
-    public void onCastTarget(Buff buff, CastScope cast) {
+    public boolean onCastTarget(Buff buff, CastScope cast) {
         if (!isDamageCast(cast) || buff.target().cell().coordinate().distance(cast.caster().cell()) != 1) {
-            return;
+            return true;
         }
 
         if (!random.bool(buff.effect().min())) {
-            return;
+            return true;
         }
 
         applier.apply(cast.caster(), buff.target(), buff.effect().max());
         cast.removeTarget(buff.target());
+
+        return false;
     }
 
     /**

src/main/java/fr/quatrevieux/araknemu/game/fight/castable/effect/handler/shifting/SwitchPositionApplier.java

@@ -0,0 +1,60 @@
+/*
+ * This file is part of Araknemu.
+ *
+ * Araknemu is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Araknemu 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Araknemu.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * Copyright (c) 2017-2021 Vincent Quatrevieux
+ */
+
+package fr.quatrevieux.araknemu.game.fight.castable.effect.handler.shifting;
+
+import fr.quatrevieux.araknemu.game.fight.Fight;
+import fr.quatrevieux.araknemu.game.fight.fighter.ActiveFighter;
+import fr.quatrevieux.araknemu.game.fight.fighter.PassiveFighter;
+import fr.quatrevieux.araknemu.game.fight.map.FightCell;
+import fr.quatrevieux.araknemu.network.game.out.fight.action.ActionEffect;
+
+/**
+ * Perform the switch position of two fighters
+ */
+public final class SwitchPositionApplier {
+    private final Fight fight;
+
+    public SwitchPositionApplier(Fight fight) {
+        this.fight = fight;
+    }
+
+    /**
+     * Apply the switch effect
+     *
+     * @param caster The switch spell caster
+     * @param target The other fighter to switch with
+     */
+    public void apply(ActiveFighter caster, PassiveFighter target) {
+        final FightCell casterCell = caster.cell();
+        final FightCell targetCell = target.cell();
+
+        // Unset cells
+        caster.move(null);
+        target.move(null);
+
+        // Switch cells
+        caster.move(targetCell);
+        target.move(casterCell);
+
+        // Synchronize positions with client
+        fight.send(ActionEffect.teleport(caster, caster, targetCell));
+        fight.send(ActionEffect.teleport(caster, target, casterCell));
+    }
+}