Add FishHookStateChangeEvent to detect fishing hook state transitions.

paper-api/src/main/java/io/papermc/paper/event/entity/FishHookStateChangeEvent.java

@@ -0,0 +1,52 @@
+package io.papermc.paper.event.entity;
+
+import org.bukkit.entity.FishHook;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.entity.EntityEvent;
+import org.bukkit.event.player.PlayerFishEvent;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * Called just before a {@link FishHook}'s {@link FishHook.HookState} is changed.
+ *
+ * <p>If you want to monitor a player's fishing state transition, you can use {@link PlayerFishEvent}.</p>
+ */
+@NullMarked
+public final class FishHookStateChangeEvent extends EntityEvent {
+
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+
+    private final FishHook.HookState newHookState;
+
+    @ApiStatus.Internal
+    public FishHookStateChangeEvent(final FishHook entity, final FishHook.HookState newHookState) {
+        super(entity);
+        this.newHookState = newHookState;
+    }
+
+    /**
+     * Get the <strong>new</strong> hook state of the {@link FishHook}.
+     *
+     * <p>Refer to {@link FishHook#getState()} to get the current hook state.</p>
+     *
+     * @return the <strong>new</strong> hook state
+     */
+    public FishHook.HookState getNewHookState() {
+        return this.newHookState;
+    }
+
+    @Override
+    public FishHook getEntity() {
+        return (FishHook) super.getEntity();
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return HANDLER_LIST;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLER_LIST;
+    }
+}

paper-api/src/main/java/org/bukkit/entity/FishHook.java

@@ -1,6 +1,7 @@
 package org.bukkit.entity;
 
 import org.bukkit.inventory.EquipmentSlot;
+import io.papermc.paper.event.entity.FishHookStateChangeEvent;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -306,6 +307,7 @@ public interface FishHook extends Projectile {
 
     /**
      * Represents a state in which a fishing hook may be.
+     * State transitions can be listened for using {@link FishHookStateChangeEvent}
      */
     public enum HookState {
 

paper-api/src/main/java/org/bukkit/event/player/PlayerFishEvent.java

@@ -1,5 +1,6 @@
 package org.bukkit.event.player;
 
+import io.papermc.paper.event.entity.FishHookStateChangeEvent;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.FishHook;
 import org.bukkit.entity.Player;
@@ -12,6 +13,8 @@
 
 /**
  * Thrown when a player is fishing
+ *
+ * <p>If you want to monitor a fishhooks state transition, you can use {@link FishHookStateChangeEvent}.</p>
  */
 public class PlayerFishEvent extends PlayerEvent implements Cancellable {
 

paper-server/patches/sources/net/minecraft/world/entity/projectile/FishingHook.java.patch

@@ -42,6 +42,29 @@
                      return;
                  }
              } else {
+@@ -166,12 +_,14 @@
+             if (this.currentState == FishingHook.FishHookState.FLYING) {
+                 if (this.hookedIn != null) {
+                     this.setDeltaMovement(Vec3.ZERO);
++                    new io.papermc.paper.event.entity.FishHookStateChangeEvent((org.bukkit.entity.FishHook) getBukkitEntity(), org.bukkit.entity.FishHook.HookState.HOOKED_ENTITY).callEvent(); // Paper - Add FishHookStateChangeEvent. #HOOKED_ENTITY
+                     this.currentState = FishingHook.FishHookState.HOOKED_IN_ENTITY;
+                     return;
+                 }
+
+                 if (flag) {
+                     this.setDeltaMovement(this.getDeltaMovement().multiply(0.3, 0.2, 0.3));
++                    new io.papermc.paper.event.entity.FishHookStateChangeEvent((org.bukkit.entity.FishHook) getBukkitEntity(), org.bukkit.entity.FishHook.HookState.BOBBING).callEvent(); // Paper - Add FishHookStateChangeEvent. #BOBBING
+                     this.currentState = FishingHook.FishHookState.BOBBING;
+                     return;
+                 }
+@@ -184,6 +_,7 @@
+                             this.setPos(this.hookedIn.getX(), this.hookedIn.getY(0.8), this.hookedIn.getZ());
+                         } else {
+                             this.setHookedEntity(null);
++                            new io.papermc.paper.event.entity.FishHookStateChangeEvent((org.bukkit.entity.FishHook) getBukkitEntity(), org.bukkit.entity.FishHook.HookState.UNHOOKED).callEvent(); // Paper - Add FishHookStateChangeEvent. #UNHOOKED
+                             this.currentState = FishingHook.FishHookState.FLYING;
+                         }
+                     }
 @@ -247,14 +_,14 @@
          if (!player.isRemoved() && player.isAlive() && (isFishingRod || isFishingRod1) && !(this.distanceToSqr(player) > 1024.0)) {
              return false;