Fix the oxygen usage when entering water

src/main/java/micdoodle8/mods/galacticraft/core/util/OxygenUtil.java

@@ -433,26 +433,64 @@ public static boolean inOxygenBubble(World worldObj, double avgX, double avgY, d
      * @param player The player to check and apply the effect to.
      */
     public static void applyWaterBreathingEffect(EntityPlayerMP player) {
-        // Check if the player is in water
-        if (player.isInWater()) {
-            // Check if the player has valid oxygen gear setup
-            if (hasValidOxygenSetup(player)) {
-                // Apply the water breathing effect
-                player.addPotionEffect(new PotionEffect(Potion.waterBreathing.id, 220, 0, true));
-
-                // Consume oxygen
-                GCPlayerStats stats = GCPlayerStats.get(player);
-                ItemStack tankInSlot1 = stats.extendedInventory.getStackInSlot(2);
-                ItemStack tankInSlot2 = stats.extendedInventory.getStackInSlot(3);
-
-                if (tankInSlot1 != null && tankInSlot1.getItem() instanceof ItemOxygenTank
-                        && tankInSlot1.getMaxDamage() - tankInSlot1.getItemDamage() > 0) {
-                    tankInSlot1.damageItem(1, player);
-                } else if (tankInSlot2 != null && tankInSlot2.getItem() instanceof ItemOxygenTank
-                        && tankInSlot2.getMaxDamage() - tankInSlot2.getItemDamage() > 0) {
-                            tankInSlot2.damageItem(1, player);
-                        }
-            }
+        if (!isHeadInWater(player)) {
+            return;
+        }
+
+        if (hasSufficientWaterBreathing(player)) {
+            return;
+        }
+
+        if (!hasValidOxygenSetup(player)) {
+            return;
+        }
+
+        GCPlayerStats stats = GCPlayerStats.get(player);
+        ItemStack tank1 = stats.extendedInventory.getStackInSlot(2);
+        ItemStack tank2 = stats.extendedInventory.getStackInSlot(3);
+
+        if (!hasOxygen(tank1) && !hasOxygen(tank2)) {
+            return;
+        }
+
+        // Apply effect
+        player.addPotionEffect(new PotionEffect(Potion.waterBreathing.id, 220, 0, true));
+
+        // Consume oxygen (prefer first tank)
+        if (!consumeOxygen(tank1, player)) {
+            consumeOxygen(tank2, player);
+        }
+    }
+
+    private static boolean isHeadInWater(EntityPlayerMP player) {
+        double eyeY = player.posY + player.getEyeHeight();
+        int x = MathHelper.floor_double(player.posX);
+        int y = MathHelper.floor_double(eyeY);
+        int z = MathHelper.floor_double(player.posZ);
+
+        return player.worldObj.getBlock(x, y, z).getMaterial() == Material.water;
+    }
+
+    private static boolean hasSufficientWaterBreathing(EntityPlayerMP player) {
+        if (!player.isPotionActive(Potion.waterBreathing)) {
+            return false;
+        }
+
+        PotionEffect effect = player.getActivePotionEffect(Potion.waterBreathing);
+        return effect != null && (effect.getDuration() > 220 || effect.getAmplifier() > 0);
+    }
+
+    private static boolean hasOxygen(ItemStack tank) {
+        return tank != null && tank.getItem() instanceof ItemOxygenTank
+                && tank.getMaxDamage() - tank.getItemDamage() > 0;
+    }
+
+    private static boolean consumeOxygen(ItemStack tank, EntityPlayerMP player) {
+        if (!hasOxygen(tank)) {
+            return false;
         }
+
+        tank.damageItem(1, player);
+        return true;
     }
 }