Implement client-side spell counter for NPCs, fixes #345

Also makes all the continuous-spell-related methods in ISpellCaster default methods so they don't need implementing unless actually necessary.

src/main/java/electroblob/wizardry/WizardryEventHandler.java

@@ -347,18 +347,21 @@ public final class WizardryEventHandler {
 
 				Spell spell = ((ISpellCaster)event.getEntity()).getContinuousSpell();
 				SpellModifiers modifiers = ((ISpellCaster)event.getEntity()).getModifiers();
+				int count = ((ISpellCaster)event.getEntity()).getSpellCounter();
 
 				if(spell != null && spell != Spells.none){ // IntelliJ is wrong, do NOT remove the null check!
 
 					if(!MinecraftForge.EVENT_BUS.post(new SpellCastEvent.Tick(SpellCastEvent.Source.NPC, spell, event.getEntityLiving(),
-							modifiers, 0))){
+							modifiers, count))){
 
-						spell.cast(event.getEntity().world, (EntityLiving)event.getEntity(), EnumHand.MAIN_HAND, 0,
+						spell.cast(event.getEntity().world, (EntityLiving)event.getEntity(), EnumHand.MAIN_HAND, count,
 								// TODO: This implementation of modifiers relies on them being accessible client-side.
 								// 		 Right now that doesn't matter because NPCs don't use modifiers, but they might in future
 								((EntityLiving)event.getEntity()).getAttackTarget(), modifiers);
 					}
 				}
+
+				((ISpellCaster)event.getEntity()).setSpellCounter(count + 1);
 			}
 		}
 	}

src/main/java/electroblob/wizardry/client/ClientProxy.java

@@ -434,6 +434,7 @@ public class ClientProxy extends CommonProxy {
 				if(caster instanceof ISpellCaster){
 					if(spell.isContinuous || spell instanceof None){
 						((ISpellCaster)caster).setContinuousSpell(spell);
+						((ISpellCaster)caster).setSpellCounter(spell instanceof None ? 0 : 1);
 						((EntityLiving)caster).setAttackTarget((EntityLivingBase)target);
 					}
 				}

src/main/java/electroblob/wizardry/entity/living/EntityAIAttackSpell.java

@@ -213,6 +213,7 @@ public class EntityAIAttackSpell<T extends EntityLiving & ISpellCaster> extends
 			return false;
 		}
 
+		// This is only called when spell casting starts so ticksInUse is always zero
 		if(spell.cast(attacker.world, attacker, EnumHand.MAIN_HAND, 0, target, modifiers)){
 
 			if(spell.isContinuous){

src/main/java/electroblob/wizardry/entity/living/EntityEvilWizard.java

@@ -74,6 +74,7 @@ public class EntityEvilWizard extends EntityMob implements ISpellCaster, IEntity
 	// Field implementations
 	private List<Spell> spells = new ArrayList<Spell>(4);
 	private Spell continuousSpell;
+	private int spellCounter;
 
 	public EntityEvilWizard(World world){
 
@@ -175,6 +176,16 @@ public class EntityEvilWizard extends EntityMob implements ISpellCaster, IEntity
 	public Spell getContinuousSpell(){
 		return this.continuousSpell;
 	}
+
+	@Override
+	public void setSpellCounter(int count){
+		spellCounter = count;
+	}
+
+	@Override
+	public int getSpellCounter(){
+		return spellCounter;
+	}
 	
 	@Override
 	public int getAimingError(EnumDifficulty difficulty){

src/main/java/electroblob/wizardry/entity/living/EntityPhoenix.java

@@ -30,6 +30,7 @@ public class EntityPhoenix extends EntitySummonedCreature implements ISpellCaste
 	private EntityAIAttackSpell<EntityPhoenix> spellAttackAI = new EntityAIAttackSpell<>(this, AISpeed, 15f, 60, 140);
 
 	private Spell continuousSpell;
+	private int spellCounter;
 
 	private static final List<Spell> attack = Collections.singletonList(Spells.flame_ray);
 
@@ -76,6 +77,16 @@ public class EntityPhoenix extends EntitySummonedCreature implements ISpellCaste
 		continuousSpell = spell;
 	}
 
+	@Override
+	public void setSpellCounter(int count){
+		spellCounter = count;
+	}
+
+	@Override
+	public int getSpellCounter(){
+		return spellCounter;
+	}
+
 	@Override
 	public boolean hasRangedAttack(){
 		return true;

src/main/java/electroblob/wizardry/entity/living/EntityShadowWraith.java

@@ -61,21 +61,6 @@ public class EntityShadowWraith extends EntitySummonedCreature implements ISpell
 		return attack;
 	}
 
-	@Override
-	public SpellModifiers getModifiers(){
-		return new SpellModifiers();
-	}
-
-	@Override
-	public Spell getContinuousSpell(){
-		return Spells.none;
-	}
-
-	@Override
-	public void setContinuousSpell(Spell spell){
-		// Doesn't use continuous spells.
-	}
-
 	@Override
 	protected void applyEntityAttributes(){
 		super.applyEntityAttributes();

src/main/java/electroblob/wizardry/entity/living/EntityStormElemental.java

@@ -59,21 +59,6 @@ public class EntityStormElemental extends EntitySummonedCreature implements ISpe
 		return attack;
 	}
 
-	@Override
-	public SpellModifiers getModifiers(){
-		return new SpellModifiers();
-	}
-
-	@Override
-	public Spell getContinuousSpell(){
-		return Spells.none;
-	}
-
-	@Override
-	public void setContinuousSpell(Spell spell){
-		// Doesn't use continuous spells.
-	}
-
 	@Override
 	protected void applyEntityAttributes(){
 		super.applyEntityAttributes();

src/main/java/electroblob/wizardry/entity/living/EntityWizard.java

@@ -83,6 +83,7 @@ public class EntityWizard extends EntityCreature implements INpc, IMerchant, ISp
 	// Field implementations
 	private List<Spell> spells = new ArrayList<Spell>(4);
 	private Spell continuousSpell;
+	private int spellCounter;
 
 	/** A set of the positions of the blocks that are part of this wizard's tower. */
 	private Set<BlockPos> towerBlocks;
@@ -187,7 +188,17 @@ public class EntityWizard extends EntityCreature implements INpc, IMerchant, ISp
 	public Spell getContinuousSpell(){
 		return this.continuousSpell;
 	}
-	
+
+	@Override
+	public void setSpellCounter(int count){
+		spellCounter = count;
+	}
+
+	@Override
+	public int getSpellCounter(){
+		return spellCounter;
+	}
+
 	@Override
 	public int getAimingError(EnumDifficulty difficulty){
 		// Being more intelligent than skeletons, wizards are a little more accurate.

src/main/java/electroblob/wizardry/entity/living/ISpellCaster.java

@@ -19,7 +19,9 @@ import java.util.List;
  * packets) is handled by that class, and all the implementor needs to do is decide which spell(s) to select.
  * <p></p>
  * This class also allows Wizardry to do all the syncing necessary for continuous spell casting. All the implementor
- * needs to do is store the actual fields involved.
+ * needs to do is store the actual fields involved, by implementing {@link ISpellCaster#setContinuousSpell(Spell)},
+ * {@link ISpellCaster#getContinuousSpell()}, {@link ISpellCaster#setSpellCounter(int)}, {@link ISpellCaster#getSpellCounter()}
+ * and {@link ISpellCaster#getModifiers()}.
  */
 /* Perhaps this should be a capability? Though I can't help thinking they're mainly for attaching data to vanilla
  * classes, rather than custom ones. For now, the main purpose of this is to centralise code within wizardry itself, and
@@ -39,7 +41,7 @@ public interface ISpellCaster {
 	 *         list <b>must</b> be castable by NPCs (i.e. {@link Spell#canBeCastBy(net.minecraft.entity.EntityLiving, boolean)} returns true).
 	 */
 	@Nonnull
-	public List<Spell> getSpells();
+	List<Spell> getSpells();
 
 	/**
 	 * Called each time the entity attacks to get the modifiers to apply to the spell.
@@ -48,31 +50,47 @@ public interface ISpellCaster {
 	 *         required, pass in an empty {@code SpellModifiers} object.
 	 */
 	@Nonnull
-	public SpellModifiers getModifiers();
+	default SpellModifiers getModifiers(){
+		return new SpellModifiers(); // May seem wasteful but this should never be called so it doesn't matter
+	}
 
 	/**
 	 * Returns the continuous spell that is currently being cast, or the None spell if there is none. Implementors
 	 * should simply store this as a private field and return it here. Will be synced by the AI class, but whether it is
-	 * saved to NBT is up to you. If the implementing class does not deal with continuous spells, just return
+	 * saved to NBT is up to you. If the implementing class only ever uses one continuous spell, do <b>not</b> just
-	 * {@link Spells#none}. If the implementing class only ever uses one continuous spell, do <b>not</b> just return
+	 * return that spell; the field must still be stored.
-	 * that spell; the field must still be stored.
 	 */
 	@Nonnull
-	public Spell getContinuousSpell();
+	default Spell getContinuousSpell(){
+		return Spells.none;
+	}
 
 	/**
 	 * Sets the continuous spell that is currently being cast, or the None spell if there is none. Implementors should
 	 * simply store this as a private field and assign it here. Will be synced by the AI class, but whether it is saved
 	 * to NBT is up to you. If the implementing class does not deal with continuous spells, leave this method blank.
 	 */
-	public void setContinuousSpell(Spell spell);
+	default void setContinuousSpell(Spell spell){
+		// Do nothing
+	}
+
+	/** Returns the number of ticks the current spell has been cast for. Implementors should simply store this as a
+	 * private field and return it here. This is only used client-side. */
+	default int getSpellCounter(){
+		return 0;
+	}
+
+	/** Sets the number of ticks the current spell has been cast for. Implementors should simply store this as a
+	 * private field and assign it here. This is only used client-side. */
+	default void setSpellCounter(int count){
+		// Do nothing
+	}
 	
 	/**
 	 * Returns the aiming error for the given difficulty, used in projectile spells. Defaults to the values used by
 	 * skeletons, which are: Easy - 10, Normal - 6, Hard - 2, Peaceful - 10 (rarely used).
 	 */
-	// This is what default methods are actually intended for!
+	default int getAimingError(EnumDifficulty difficulty) {
-	public default int getAimingError(EnumDifficulty difficulty) {
 		return WizardryUtilities.getDefaultAimingError(difficulty);
 	}
 }