Replace setBaseDamage and setFinalDamage with damage steps

Author: Yeregorix

src/main/java/org/spongepowered/api/event/cause/entity/damage/DamageStepTypes.java

@@ -108,6 +108,13 @@ public final class DamageStepTypes {
      */
     public static final DefaultedRegistryReference<DamageStepType> ENCHANTMENT_COOLDOWN = DamageStepTypes.key(ResourceKey.sponge("enchantment_cooldown"));
 
+    /**
+     * Represents the last {@link DamageStep} applied during a damage calculation.
+     * This step happens just before the {@link org.spongepowered.api.event.entity.DamageCalculationEvent.Post}.
+     * This step does nothing but can be used to add modifiers to the final damage.
+     */
+    public static final DefaultedRegistryReference<DamageStepType> END = DamageStepTypes.key(ResourceKey.sponge("end"));
+
     /**
      * Represents a {@link DamageStep} that will modify freezing damage.
      * E.g. {@link org.spongepowered.api.entity.living.monster.Blaze} take more damage from freezing sources.
@@ -152,6 +159,13 @@ public final class DamageStepTypes {
      */
     public static final DefaultedRegistryReference<DamageStepType> SHIELD = DamageStepTypes.key(ResourceKey.sponge("shield"));
 
+    /**
+     * Represents the first {@link DamageStep} applied during a damage calculation.
+     * This step happens just after the {@link org.spongepowered.api.event.entity.DamageCalculationEvent.Pre}.
+     * This step does nothing but can be used to add modifiers to the base damage.
+     */
+    public static final DefaultedRegistryReference<DamageStepType> START = DamageStepTypes.key(ResourceKey.sponge("start"));
+
     /**
      * Represents a {@link DamageStep} that is applied for a sweeping attack.
      */

src/main/java/org/spongepowered/api/event/entity/DamageCalculationEvent.java

@@ -31,6 +31,7 @@
 import org.spongepowered.api.event.cause.entity.damage.DamageModifier;
 import org.spongepowered.api.event.cause.entity.damage.DamageStep;
 import org.spongepowered.api.event.cause.entity.damage.DamageStepType;
+import org.spongepowered.api.event.cause.entity.damage.DamageStepTypes;
 import org.spongepowered.api.event.impl.entity.AbstractDamageCalculationEventPre;
 import org.spongepowered.api.item.inventory.ItemStack;
 import org.spongepowered.api.world.difficulty.Difficulty;
@@ -48,7 +49,7 @@
  *
  * <p>Optimally, these steps can be traced to a
  * particular object, be it an {@link ItemStack}, {@link Difficulty}, or
- * simply an an attribute. Given that {@link Cause} has a unique capability of
+ * simply an attribute. Given that {@link Cause} has a unique capability of
  * storing any and every {@link Object} willing to be passed into it, we
  * can easily represent these "sources" of "steps" in a {@link Cause}.
  * Now, knowing the "source" will not provide enough information, so a
@@ -65,17 +66,10 @@ public interface DamageCalculationEvent extends Event, Cancellable {
      */
     Entity entity();
 
-    /**
-     * Gets the original base damage to deal to the targeted {@link Entity}.
-     *
-     * @see #baseDamage()
-     * @return The original base damage
-     */
-    double originalBaseDamage();
-
     /**
      * Gets the base damage to deal to the targeted {@link Entity}.
      * The base damage is the value before the calculation and its {@link DamageStep}s.
+     * To modify the base damage, add a modifier to the step associated to {@link DamageStepTypes#START}.
      *
      * @return The base damage
      */
@@ -88,14 +82,6 @@ public interface DamageCalculationEvent extends Event, Cancellable {
     @ImplementedBy(AbstractDamageCalculationEventPre.class)
     interface Pre extends DamageCalculationEvent {
 
-        /**
-         * Sets the base damage to deal to the targeted {@link Entity}.
-         *
-         * @see #baseDamage()
-         * @param baseDamage The base damage
-         */
-        void setBaseDamage(double baseDamage);
-
         /**
          * Gets a mutable list of all modifiers that applies just before the step.
          *
@@ -120,31 +106,16 @@ interface Pre extends DamageCalculationEvent {
      */
     interface Post extends DamageCalculationEvent {
 
-        /**
-         * Gets the original final damage to deal to the targeted {@link Entity}.
-         *
-         * @see #finalDamage()
-         * @return The final amount of damage to originally deal
-         */
-        double originalFinalDamage();
-
         /**
          * Gets the final damage to deal to the targeted {@link Entity}.
          * The final damage is the value after the calculation and its {@link DamageStep}s.
          * The final damage is the amount of health being lost by the {@link Entity}, if health is tracked.
+         * To modify the final damage, add a modifier to the step associated to {@link DamageStepTypes#END}.
          *
          * @return The final damage
          */
         double finalDamage();
 
-        /**
-         * Sets the final damage to deal to the targeted {@link Entity}.
-         *
-         * @see #finalDamage()
-         * @param finalDamage The base damage
-         */
-        void setFinalDamage(double finalDamage);
-
         /**
          * Gets the list of the captured steps during the damage calculation in the order they have been applied.
          * Note that this list is not an exhaustive representation of all the operations applied,