[UI/UX] Implement Discard Button (#5985)

* [feature]Implemented needed parts for discard function from issue #4780:
-TryDiscardFunction in battlescene;
-Created a party discard mode button;
-Updated Transfer button in modifier-select-ui-handler to Manage items;
-Created tests for the discard function in test/ui;
-Added images for the new discard and transfer buttons to loading-scene;
-Created placeholder messages for discard feature in party-ui-handler;

Co-authored-by: Tiago Rodrigues <tiago.n.rodrigues@tecnico.ulisboa.pt>

* [Fix] Updated icon for dynamic messaging

* [Fix] Corrected legacy mode icons and adjusted double-battle button location

* [Fix]Adjusted button positioning and mapping after review. Mapping requires debugging.

* [Fix] Fixed visible pokeball in legacy mode and key mapping

* [Fix] Background fixes,manage menu is the only one affected by changes now

* Implement i18n keys

* [Fix] implemented most code optimizations and callbacks to the modified locales folder

* [Fix] Implemented 3 suggestions

* [Fix]improved/corrected test structure

Co-authored-by: NightKev <34855794+DayKev@users.noreply.github.com>

* [Fix] added functionality test for the discard button

* [Fix] added necessary comment

Co-authored-by: Bertie690 <136088738+Bertie690@users.noreply.github.com>

* [Fix] Implemented suggested changes in test/discard text prompt

* [Fix] Implemented UI suggestions and removed discard text confirmation

* [Fix] added missing imports

* Fix imports in test file

* [Fix] Implemented suggested cursor behavior and reworked test code

* [Fix] Corrected failed test

* [Fix] atempting to fix the test timeout issue

* [Fix] Undoing latest attempt

* [Fix] Implemented suggestions to fix broken tests

* Reviews

* [Fix] replaced icon images

* [Fix] Updated jsons to match new icons and removed pokeball icon from legacy mode

* Optimized new images

* [Fix] Fixed referenced bug and added similar confirmation box to release

* [Fix] Updated tests to handle the corfirmation box

* [Fix] Added back the accidentally removed changes

* [Fix]updated incorrect import path

* [fix] add description for the manageItemMode function

Co-authored-by: Bertie690 <136088738+Bertie690@users.noreply.github.com>

* Update src/ui/party-ui-handler.ts

Co-authored-by: Bertie690 <136088738+Bertie690@users.noreply.github.com>

* [Fix] corrected formating issue

---------

Co-authored-by: Mikhail Shueb <mikhail.shueb@tecnico.ulisboa.pt>
Co-authored-by: NightKev <34855794+DayKev@users.noreply.github.com>
Co-authored-by: Bertie690 <136088738+Bertie690@users.noreply.github.com>
Co-authored-by: damocleas <damocleas25@gmail.com>
Co-authored-by: Bertie690 <taylormw163@gmail.com>
Co-authored-by: Adri1 <adrien.grivel@hotmail.fr>

public/images/ui/legacy/party_discard.json

@@ -0,0 +1,62 @@
+{
+	"textures": [
+		{
+			"image": "party_discard.png",
+			"format": "RGBA8888",
+			"size": {
+				"w": 75,
+				"h": 50
+			},
+			"scale": 1,
+			"frames": [
+				{
+					"filename": "normal",
+					"rotated": false,
+					"trimmed": false,
+					"sourceSize": {
+						"w": 75,
+						"h": 25
+					},
+					"spriteSourceSize": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					},
+					"frame": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					}
+				},
+				{
+					"filename": "selected",
+					"rotated": false,
+					"trimmed": false,
+					"sourceSize": {
+						"w": 75,
+						"h": 25
+					},
+					"spriteSourceSize": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					},
+					"frame": {
+						"x": 0,
+						"y": 25,
+						"w": 75,
+						"h": 25
+					}
+				}
+			]
+		}
+	],
+	"meta": {
+		"app": "https://www.codeandweb.com/texturepacker",
+		"version": "3.0",
+		"smartupdate": "$TexturePacker:SmartUpdate:17219773dfffd6b1204d988fea3f9462:1127ad21d64bc7ebb9df4fc28f3d2d39:7ad46e8fb4648c3d3d84a746ecb371ea$"
+	}
+}

public/images/ui/legacy/party_transfer.json

@@ -0,0 +1,62 @@
+{
+	"textures": [
+		{
+			"image": "party_transfer.png",
+			"format": "RGBA8888",
+			"size": {
+				"w": 75,
+				"h": 50
+			},
+			"scale": 1,
+			"frames": [
+				{
+					"filename": "normal",
+					"rotated": false,
+					"trimmed": false,
+					"sourceSize": {
+						"w": 75,
+						"h": 25
+					},
+					"spriteSourceSize": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					},
+					"frame": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					}
+				},
+				{
+					"filename": "selected",
+					"rotated": false,
+					"trimmed": false,
+					"sourceSize": {
+						"w": 75,
+						"h": 25
+					},
+					"spriteSourceSize": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					},
+					"frame": {
+						"x": 0,
+						"y": 25,
+						"w": 75,
+						"h": 25
+					}
+				}
+			]
+		}
+	],
+	"meta": {
+		"app": "https://www.codeandweb.com/texturepacker",
+		"version": "3.0",
+		"smartupdate": "$TexturePacker:SmartUpdate:17219773dfffd6b1204d988fea3f9462:1127ad21d64bc7ebb9df4fc28f3d2d39:7ad46e8fb4648c3d3d84a746ecb371ea$"
+	}
+}

public/images/ui/party_discard.json

@@ -0,0 +1,62 @@
+{
+	"textures": [
+		{
+			"image": "party_discard.png",
+			"format": "RGBA8888",
+			"size": {
+				"w": 75,
+				"h": 50
+			},
+			"scale": 1,
+			"frames": [
+				{
+					"filename": "normal",
+					"rotated": false,
+					"trimmed": false,
+					"sourceSize": {
+						"w": 75,
+						"h": 25
+					},
+					"spriteSourceSize": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					},
+					"frame": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					}
+				},
+				{
+					"filename": "selected",
+					"rotated": false,
+					"trimmed": false,
+					"sourceSize": {
+						"w": 75,
+						"h": 25
+					},
+					"spriteSourceSize": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					},
+					"frame": {
+						"x": 0,
+						"y": 25,
+						"w": 75,
+						"h": 25
+					}
+				}
+			]
+		}
+	],
+	"meta": {
+		"app": "https://www.codeandweb.com/texturepacker",
+		"version": "3.0",
+		"smartupdate": "$TexturePacker:SmartUpdate:17219773dfffd6b1204d988fea3f9462:1127ad21d64bc7ebb9df4fc28f3d2d39:7ad46e8fb4648c3d3d84a746ecb371ea$"
+	}
+}

public/images/ui/party_transfer.json

@@ -0,0 +1,62 @@
+{
+	"textures": [
+		{
+			"image": "party_transfer.png",
+			"format": "RGBA8888",
+			"size": {
+				"w": 75,
+				"h": 50
+			},
+			"scale": 1,
+			"frames": [
+				{
+					"filename": "normal",
+					"rotated": false,
+					"trimmed": false,
+					"sourceSize": {
+						"w": 75,
+						"h": 25
+					},
+					"spriteSourceSize": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					},
+					"frame": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					}
+				},
+				{
+					"filename": "selected",
+					"rotated": false,
+					"trimmed": false,
+					"sourceSize": {
+						"w": 75,
+						"h": 25
+					},
+					"spriteSourceSize": {
+						"x": 0,
+						"y": 0,
+						"w": 75,
+						"h": 25
+					},
+					"frame": {
+						"x": 0,
+						"y": 25,
+						"w": 75,
+						"h": 25
+					}
+				}
+			]
+		}
+	],
+	"meta": {
+		"app": "https://www.codeandweb.com/texturepacker",
+		"version": "3.0",
+		"smartupdate": "$TexturePacker:SmartUpdate:17219773dfffd6b1204d988fea3f9462:1127ad21d64bc7ebb9df4fc28f3d2d39:7ad46e8fb4648c3d3d84a746ecb371ea$"
+	}
+}

src/battle-scene.ts

@@ -2845,6 +2845,23 @@ export class BattleScene extends SceneBase {
     }
     return false;
   }
+  /**
+   * Attempt to discard one or more copies of a held item.
+   * @param itemModifier - The {@linkcode PokemonHeldItemModifier} being discarded
+   * @param discardQuantity - The number of copies to remove (up to the amount currently held); default `1`
+   * @returns Whether the item was successfully discarded.
+   * Removing fewer items than requested is still considered a success.
+   */
+  tryDiscardHeldItemModifier(itemModifier: PokemonHeldItemModifier, discardQuantity = 1): boolean {
+    const countTaken = Math.min(discardQuantity, itemModifier.stackCount);
+    itemModifier.stackCount -= countTaken;
+
+    if (itemModifier.stackCount > 0) {
+      return true;
+    }
+
+    return this.removeModifier(itemModifier);
+  }
 
   canTransferHeldItemModifier(itemModifier: PokemonHeldItemModifier, target: Pokemon, transferQuantity = 1): boolean {
     const mod = itemModifier.clone() as PokemonHeldItemModifier;

src/loading-scene.ts

@@ -119,6 +119,7 @@ export class LoadingScene extends SceneBase {
 
     this.loadImage("party_bg", "ui");
     this.loadImage("party_bg_double", "ui");
+    this.loadImage("party_bg_double_manage", "ui");
     this.loadAtlas("party_slot_main", "ui");
     this.loadAtlas("party_slot", "ui");
     this.loadImage("party_slot_overlay_lv", "ui");
@@ -126,6 +127,8 @@ export class LoadingScene extends SceneBase {
     this.loadAtlas("party_slot_hp_overlay", "ui");
     this.loadAtlas("party_pb", "ui");
     this.loadAtlas("party_cancel", "ui");
+    this.loadAtlas("party_discard", "ui");
+    this.loadAtlas("party_transfer", "ui");
 
     this.loadImage("summary_bg", "ui");
     this.loadImage("summary_overlay_shiny", "ui");

src/ui/modifier-select-ui-handler.ts

@@ -69,7 +69,7 @@ export class ModifierSelectUiHandler extends AwaitableUiHandler {
 
     if (context) {
       context.font = styleOptions.fontSize + "px " + styleOptions.fontFamily;
-      this.transferButtonWidth = context.measureText(i18next.t("modifierSelectUiHandler:transfer")).width;
+      this.transferButtonWidth = context.measureText(i18next.t("modifierSelectUiHandler:manageItems")).width;
       this.checkButtonWidth = context.measureText(i18next.t("modifierSelectUiHandler:checkTeam")).width;
     }
 
@@ -81,7 +81,7 @@ export class ModifierSelectUiHandler extends AwaitableUiHandler {
     this.transferButtonContainer.setVisible(false);
     ui.add(this.transferButtonContainer);
 
-    const transferButtonText = addTextObject(-4, -2, i18next.t("modifierSelectUiHandler:transfer"), TextStyle.PARTY);
+    const transferButtonText = addTextObject(-4, -2, i18next.t("modifierSelectUiHandler:manageItems"), TextStyle.PARTY);
     transferButtonText.setName("text-transfer-btn");
     transferButtonText.setOrigin(1, 0);
     this.transferButtonContainer.add(transferButtonText);
@@ -601,7 +601,7 @@ export class ModifierSelectUiHandler extends AwaitableUiHandler {
         (globalScene.game.canvas.width - this.transferButtonWidth - this.checkButtonWidth) / 6 - 30,
         OPTION_BUTTON_YPOSITION + 4,
       );
-      ui.showText(i18next.t("modifierSelectUiHandler:transferDesc"));
+      ui.showText(i18next.t("modifierSelectUiHandler:manageItemsDesc"));
     } else if (cursor === 2) {
       this.cursorObj.setPosition(
         (globalScene.game.canvas.width - this.checkButtonWidth) / 6 - 10,

src/ui/party-ui-handler.ts

@@ -103,6 +103,11 @@ export enum PartyUiMode {
    * This is generally used in for Mystery Encounter or special effects that require the player to select a Pokemon
    */
   SELECT,
+  /**
+   * Indicates that the party UI is open to select a party member from which items will be discarded.
+   * This type of selection can be cancelled.
+   */
+  DISCARD,
 }
 
 export enum PartyOption {
@@ -121,6 +126,7 @@ export enum PartyOption {
   RELEASE,
   RENAME,
   SELECT,
+  DISCARD,
   SCROLL_UP = 1000,
   SCROLL_DOWN = 1001,
   FORM_CHANGE_ITEM = 2000,
@@ -155,6 +161,7 @@ export class PartyUiHandler extends MessageUiHandler {
   private partySlotsContainer: Phaser.GameObjects.Container;
   private partySlots: PartySlot[];
   private partyCancelButton: PartyCancelButton;
+  private partyDiscardModeButton: PartyDiscardModeButton;
   private partyMessageBox: Phaser.GameObjects.NineSlice;
   private moveInfoOverlay: MoveInfoOverlay;
 
@@ -180,6 +187,8 @@ export class PartyUiHandler extends MessageUiHandler {
   private transferAll: boolean;
 
   private lastCursor = 0;
+  private lastLeftPokemonCursor = 0;
+  private lastRightPokemonCursor = 0;
   private selectCallback: PartySelectCallback | PartyModifierTransferSelectCallback | null;
   private selectFilter: PokemonSelectFilter | PokemonModifierTransferSelectFilter;
   private moveSelectFilter: PokemonMoveSelectFilter;
@@ -308,6 +317,12 @@ export class PartyUiHandler extends MessageUiHandler {
     this.iconAnimHandler = new PokemonIconAnimHandler();
     this.iconAnimHandler.setup();
 
+    const partyDiscardModeButton = new PartyDiscardModeButton(60, -globalScene.game.canvas.height / 15 - 1, this);
+
+    partyContainer.add(partyDiscardModeButton);
+
+    this.partyDiscardModeButton = partyDiscardModeButton;
+
     // prepare move overlay. in case it appears to be too big, set the overlayScale to .5
     const overlayScale = 1;
     this.moveInfoOverlay = new MoveInfoOverlay({
@@ -349,8 +364,18 @@ export class PartyUiHandler extends MessageUiHandler {
     this.showMovePp = args.length > 6 && args[6];
 
     this.partyContainer.setVisible(true);
+    if (this.isItemManageMode()) {
+      this.partyBg.setTexture(`party_bg${globalScene.currentBattle.double ? "_double_manage" : ""}`);
+    } else {
       this.partyBg.setTexture(`party_bg${globalScene.currentBattle.double ? "_double" : ""}`);
+    }
+
     this.populatePartySlots();
+    // If we are currently transferring items, set the icon to its proper state and reveal the button.
+    if (this.isItemManageMode()) {
+      this.partyDiscardModeButton.toggleIcon(this.partyUiMode as PartyUiMode.MODIFIER_TRANSFER | PartyUiMode.DISCARD);
+    }
+    this.showPartyText();
     this.setCursor(0);
 
     return true;
@@ -595,7 +620,7 @@ export class PartyUiHandler extends MessageUiHandler {
     const option = this.options[this.optionsCursor];
     if (button === Button.LEFT) {
       /** Decrease quantity for the current item and update UI */
-      if (this.partyUiMode === PartyUiMode.MODIFIER_TRANSFER) {
+      if (this.isItemManageMode()) {
         this.transferQuantities[option] =
           this.transferQuantities[option] === 1
             ? this.transferQuantitiesMax[option]
@@ -609,7 +634,7 @@ export class PartyUiHandler extends MessageUiHandler {
 
     if (button === Button.RIGHT) {
       /** Increase quantity for the current item and update UI */
-      if (this.partyUiMode === PartyUiMode.MODIFIER_TRANSFER) {
+      if (this.isItemManageMode()) {
         this.transferQuantities[option] =
           this.transferQuantities[option] === this.transferQuantitiesMax[option]
             ? 1
@@ -639,6 +664,45 @@ export class PartyUiHandler extends MessageUiHandler {
     return success;
   }
 
+  private processDiscardMenuInput(pokemon: PlayerPokemon) {
+    const ui = this.getUi();
+    const option = this.options[this.optionsCursor];
+    this.clearOptions();
+
+    this.blockInput = true;
+    this.showText(i18next.t("partyUiHandler:discardConfirmation"), null, () => {
+      this.blockInput = false;
+      ui.setModeWithoutClear(
+        UiMode.CONFIRM,
+        () => {
+          ui.setMode(UiMode.PARTY);
+          this.doDiscard(option, pokemon);
+        },
+        () => {
+          ui.setMode(UiMode.PARTY);
+          this.showPartyText();
+        },
+      );
+    });
+
+    return true;
+  }
+
+  private doDiscard(option: PartyOption, pokemon: PlayerPokemon) {
+    const itemModifiers = this.getTransferrableItemsFromPokemon(pokemon);
+    this.clearOptions();
+
+    if (option === PartyOption.ALL) {
+      // Discard all currently held items
+      for (let i = 0; i < itemModifiers.length; i++) {
+        globalScene.tryDiscardHeldItemModifier(itemModifiers[i], this.transferQuantities[i]);
+      }
+    } else {
+      // Discard the currently selected item
+      globalScene.tryDiscardHeldItemModifier(itemModifiers[option], this.transferQuantities[option]);
+    }
+  }
+
   private moveOptionCursor(button: Button.UP | Button.DOWN): boolean {
     if (button === Button.UP) {
       return this.setCursor(this.optionsCursor ? this.optionsCursor - 1 : this.options.length - 1);
@@ -725,6 +789,10 @@ export class PartyUiHandler extends MessageUiHandler {
       return this.processModifierTransferModeInput(pokemon);
     }
 
+    if (this.partyUiMode === PartyUiMode.DISCARD) {
+      return this.processDiscardMenuInput(pokemon);
+    }
+
     // options specific to the mode (moves)
     if (this.partyUiMode === PartyUiMode.REMEMBER_MOVE_MODIFIER) {
       return this.processRememberMoveModeInput(pokemon);
@@ -864,7 +932,7 @@ export class PartyUiHandler extends MessageUiHandler {
     }
 
     if (button === Button.LEFT || button === Button.RIGHT) {
-      if (this.partyUiMode === PartyUiMode.MODIFIER_TRANSFER) {
+      if (this.isItemManageMode()) {
         return this.processModifierTransferModeLeftRightInput(button);
       }
     }
@@ -919,10 +987,22 @@ export class PartyUiHandler extends MessageUiHandler {
     return !(this.partyUiMode === PartyUiMode.FAINT_SWITCH || this.partyUiMode === PartyUiMode.REVIVAL_BLESSING);
   }
 
+  /**
+   * Return whether this UI handler is responsible for managing items.
+   * Used to ensure proper placement of mode toggle buttons in the UI, etc.
+   * @returns Whether the current handler is responsible for managing items.
+   */
+  private isItemManageMode(): boolean {
+    return this.partyUiMode === PartyUiMode.MODIFIER_TRANSFER || this.partyUiMode === PartyUiMode.DISCARD;
+  }
+
   private processPartyActionInput(): boolean {
     const ui = this.getUi();
     if (this.cursor < 6) {
-      if (this.partyUiMode === PartyUiMode.MODIFIER_TRANSFER && !this.transferMode) {
+      if (
+        (this.partyUiMode === PartyUiMode.MODIFIER_TRANSFER && !this.transferMode) ||
+        this.partyUiMode === PartyUiMode.DISCARD
+      ) {
         /** Initialize item quantities for the selected Pokemon */
         const itemModifiers = globalScene.findModifiers(
           m =>
@@ -936,6 +1016,25 @@ export class PartyUiHandler extends MessageUiHandler {
       this.showOptions();
       ui.playSelect();
     }
+
+    // Toggle item transfer mode to discard items or vice versa
+    if (this.cursor === 7) {
+      switch (this.partyUiMode) {
+        case PartyUiMode.DISCARD:
+          this.partyUiMode = PartyUiMode.MODIFIER_TRANSFER;
+          break;
+        case PartyUiMode.MODIFIER_TRANSFER:
+          this.partyUiMode = PartyUiMode.DISCARD;
+          break;
+        default:
+          ui.playError();
+          return false;
+      }
+      this.partyDiscardModeButton.toggleIcon(this.partyUiMode);
+      ui.playSelect();
+      return true;
+    }
+
     // Pressing return button
     if (this.cursor === 6) {
       if (!this.allowCancel()) {
@@ -956,6 +1055,7 @@ export class PartyUiHandler extends MessageUiHandler {
       this.clearTransfer();
       ui.playSelect();
     } else if (this.allowCancel()) {
+      this.partyDiscardModeButton.clear();
       if (this.selectCallback) {
         const selectCallback = this.selectCallback;
         this.selectCallback = null;
@@ -974,30 +1074,74 @@ export class PartyUiHandler extends MessageUiHandler {
     const slotCount = this.partySlots.length;
     const battlerCount = globalScene.currentBattle.getBattlerCount();
 
+    if (this.lastCursor < battlerCount) {
+      this.lastLeftPokemonCursor = this.lastCursor;
+    }
+    if (this.lastCursor >= battlerCount && this.lastCursor < 6) {
+      this.lastRightPokemonCursor = this.lastCursor;
+    }
+
     let success = false;
     switch (button) {
+      // Item manage mode adds an extra 8th "toggle mode" button to the UI, located *below* both active party members.
+      // The following logic serves to ensure its menu behaviour matches its in-game position,
+      // being selected when scrolling up from the first inactive party member or down from the last active one.
       case Button.UP:
+        if (this.isItemManageMode()) {
+          if (this.cursor === 1) {
+            success = this.setCursor(globalScene.currentBattle.double ? 0 : 7);
+            break;
+          }
+          if (this.cursor === 2) {
+            success = this.setCursor(globalScene.currentBattle.double ? 7 : 1);
+            break;
+          }
+          if (this.cursor === 6) {
+            success = this.setCursor(slotCount <= globalScene.currentBattle.getBattlerCount() ? 7 : slotCount - 1);
+            break;
+          }
+          if (this.cursor === 7) {
+            success = this.setCursor(globalScene.currentBattle.double && slotCount > 1 ? 1 : 0);
+            break;
+          }
+        }
         success = this.setCursor(this.cursor ? (this.cursor < 6 ? this.cursor - 1 : slotCount - 1) : 6);
         break;
       case Button.DOWN:
+        if (this.isItemManageMode()) {
+          if (this.cursor === 0) {
+            success = this.setCursor(globalScene.currentBattle.double && slotCount > 1 ? 1 : 7);
+            break;
+          }
+          if (this.cursor === 1) {
+            success = this.setCursor(globalScene.currentBattle.double ? 7 : slotCount > 2 ? 2 : 6);
+            break;
+          }
+          if (this.cursor === 7) {
+            success = this.setCursor(
+              slotCount > globalScene.currentBattle.getBattlerCount() ? globalScene.currentBattle.getBattlerCount() : 6,
+            );
+            break;
+          }
+        }
         success = this.setCursor(this.cursor < 6 ? (this.cursor < slotCount - 1 ? this.cursor + 1 : 6) : 0);
         break;
       case Button.LEFT:
-        if (this.cursor >= battlerCount && this.cursor <= 6) {
+        if (this.cursor === 6) {
-          success = this.setCursor(0);
+          success = this.setCursor(this.isItemManageMode() ? 7 : this.lastLeftPokemonCursor);
+        }
+        if (this.cursor >= battlerCount && this.cursor < 6) {
+          success = this.setCursor(this.lastLeftPokemonCursor);
         }
         break;
       case Button.RIGHT:
-        if (slotCount === battlerCount) {
+        // Scrolling right from item transfer button or with no backup party members goes to cancel
+        if (this.cursor === 7 || slotCount <= battlerCount) {
           success = this.setCursor(6);
           break;
         }
-        if (battlerCount >= 2 && slotCount > battlerCount && this.getCursor() === 0 && this.lastCursor === 1) {
+        if (this.cursor < battlerCount) {
-          success = this.setCursor(2);
+          success = this.setCursor(this.lastRightPokemonCursor || battlerCount);
-          break;
-        }
-        if (slotCount > battlerCount && this.cursor < battlerCount) {
-          success = this.setCursor(this.lastCursor < 6 ? this.lastCursor || battlerCount : battlerCount);
           break;
         }
     }
@@ -1044,11 +1188,15 @@ export class PartyUiHandler extends MessageUiHandler {
         this.partySlots[this.lastCursor].deselect();
       } else if (this.lastCursor === 6) {
         this.partyCancelButton.deselect();
+      } else if (this.lastCursor === 7) {
+        this.partyDiscardModeButton.deselect();
       }
       if (cursor < 6) {
         this.partySlots[cursor].select();
       } else if (cursor === 6) {
         this.partyCancelButton.select();
+      } else if (cursor === 7) {
+        this.partyDiscardModeButton.select();
       }
     }
     return changed;
@@ -1143,14 +1291,16 @@ export class PartyUiHandler extends MessageUiHandler {
           optionsMessage = i18next.t("partyUiHandler:selectAnotherPokemonToSplice");
         }
         break;
+      case PartyUiMode.DISCARD:
+        optionsMessage = i18next.t("partyUiHandler:changeQuantityDiscard");
     }
 
     this.showText(optionsMessage, 0);
 
     this.updateOptions();
 
-    /** When an item is being selected for transfer, the message box is taller as the message occupies two lines */
+    /** When an item is being selected for transfer or discard, the message box is taller as the message occupies two lines */
-    if (this.partyUiMode === PartyUiMode.MODIFIER_TRANSFER) {
+    if (this.isItemManageMode()) {
       this.partyMessageBox.setSize(262 - Math.max(this.optionsBg.displayWidth - 56, 0), 42);
     } else {
       this.partyMessageBox.setSize(262 - Math.max(this.optionsBg.displayWidth - 56, 0), 30);
@@ -1159,6 +1309,20 @@ export class PartyUiHandler extends MessageUiHandler {
     this.setCursor(0);
   }
 
+  showPartyText() {
+    switch (this.partyUiMode) {
+      case PartyUiMode.MODIFIER_TRANSFER:
+        this.showText(i18next.t("partyUiHandler:partyTransfer"));
+        break;
+      case PartyUiMode.DISCARD:
+        this.showText(i18next.t("partyUiHandler:partyDiscard"));
+        break;
+      default:
+        this.showText("", 0);
+        break;
+    }
+  }
+
   private allowBatonModifierSwitch(): boolean {
     return !!(
       this.partyUiMode !== PartyUiMode.FAINT_SWITCH &&
@@ -1276,6 +1440,9 @@ export class PartyUiHandler extends MessageUiHandler {
           this.addCommonOptions(pokemon);
         }
         break;
+      case PartyUiMode.DISCARD:
+        this.updateOptionsWithModifierTransferMode(pokemon);
+        break;
       // TODO: This still needs to be broken up.
       // It could use a rework differentiating different kind of switches
       // to treat baton passing separately from switching on faint.
@@ -1381,7 +1548,8 @@ export class PartyUiHandler extends MessageUiHandler {
         optionName = "↓";
       } else if (
         (this.partyUiMode !== PartyUiMode.REMEMBER_MOVE_MODIFIER &&
-          (this.partyUiMode !== PartyUiMode.MODIFIER_TRANSFER || this.transferMode)) ||
+          (this.partyUiMode !== PartyUiMode.MODIFIER_TRANSFER || this.transferMode) &&
+          this.partyUiMode !== PartyUiMode.DISCARD) ||
         option === PartyOption.CANCEL
       ) {
         switch (option) {
@@ -1444,7 +1612,7 @@ export class PartyUiHandler extends MessageUiHandler {
       const itemModifiers = this.getItemModifiers(pokemon);
       const itemModifier = itemModifiers[option];
       if (
-        this.partyUiMode === PartyUiMode.MODIFIER_TRANSFER &&
+        this.isItemManageMode() &&
         this.transferQuantitiesMax[option] > 1 &&
         !this.transferMode &&
         itemModifier !== undefined &&
@@ -1474,7 +1642,6 @@ export class PartyUiHandler extends MessageUiHandler {
       optionText.x = 15 - this.optionsBg.width;
     }
   }
-
   startTransfer(): void {
     this.transferMode = true;
     this.transferCursor = this.cursor;
@@ -1608,7 +1775,7 @@ export class PartyUiHandler extends MessageUiHandler {
     this.eraseOptionsCursor();
 
     this.partyMessageBox.setSize(262, 30);
-    this.showText("", 0);
+    this.showPartyText();
   }
 
   eraseOptionsCursor() {
@@ -1663,6 +1830,8 @@ class PartySlot extends Phaser.GameObjects.Container {
         ? -184 +
             (globalScene.currentBattle.double ? -40 : 0) +
             (28 + (globalScene.currentBattle.double ? 8 : 0)) * slotIndex
+        : partyUiMode === PartyUiMode.MODIFIER_TRANSFER
+          ? -124 + (globalScene.currentBattle.double ? -20 : 0) + slotIndex * 55
           : -124 + (globalScene.currentBattle.double ? -8 : 0) + slotIndex * 64,
     );
 
@@ -1918,7 +2087,6 @@ class PartySlot extends Phaser.GameObjects.Container {
 
 class PartyCancelButton extends Phaser.GameObjects.Container {
   private selected: boolean;
-
   private partyCancelBg: Phaser.GameObjects.Sprite;
   private partyCancelPb: Phaser.GameObjects.Sprite;
 
@@ -1965,3 +2133,96 @@ class PartyCancelButton extends Phaser.GameObjects.Container {
     this.partyCancelPb.setFrame("party_pb");
   }
 }
+
+class PartyDiscardModeButton extends Phaser.GameObjects.Container {
+  private selected: boolean;
+  private transferIcon: Phaser.GameObjects.Sprite;
+  private discardIcon: Phaser.GameObjects.Sprite;
+  private textBox: Phaser.GameObjects.Text;
+  private party: PartyUiHandler;
+
+  constructor(x: number, y: number, party: PartyUiHandler) {
+    super(globalScene, x, y);
+
+    this.setup(party);
+  }
+
+  setup(party: PartyUiHandler) {
+    this.transferIcon = globalScene.add.sprite(0, 0, "party_transfer");
+    this.discardIcon = globalScene.add.sprite(0, 0, "party_discard");
+    this.textBox = addTextObject(-8, -7, i18next.t("partyUiHandler:TRANSFER"), TextStyle.PARTY);
+    this.party = party;
+
+    this.add(this.transferIcon);
+    this.add(this.discardIcon);
+    this.add(this.textBox);
+
+    this.clear();
+  }
+
+  select() {
+    if (this.selected) {
+      return;
+    }
+
+    this.selected = true;
+
+    this.party.showText(i18next.t("partyUiHandler:changeMode"));
+
+    this.transferIcon.setFrame("selected");
+    this.discardIcon.setFrame("selected");
+  }
+
+  deselect() {
+    if (!this.selected) {
+      return;
+    }
+
+    this.selected = false;
+    this.party.showPartyText();
+
+    this.transferIcon.setFrame("normal");
+    this.discardIcon.setFrame("normal");
+  }
+
+  /**
+   * If the current mode deals with transferring items, toggle the discard items button's name and assets.
+   * @param partyMode - The current {@linkcode PartyUiMode}
+   * @remarks
+   * This will also reveal the button if it is currently hidden.
+   */
+  public toggleIcon(partyMode: PartyUiMode.MODIFIER_TRANSFER | PartyUiMode.DISCARD): void {
+    this.setActive(true).setVisible(true);
+    switch (partyMode) {
+      case PartyUiMode.MODIFIER_TRANSFER:
+        this.transferIcon.setVisible(true);
+        this.discardIcon.setVisible(false);
+        this.textBox.setVisible(true);
+        this.textBox.setText(i18next.t("partyUiHandler:TRANSFER"));
+        this.setPosition(
+          globalScene.currentBattle.double ? 64 : 60,
+          globalScene.currentBattle.double ? -48 : -globalScene.game.canvas.height / 15 - 1,
+        );
+        this.transferIcon.displayWidth = this.textBox.text.length * 9 + 3;
+        break;
+      case PartyUiMode.DISCARD:
+        this.transferIcon.setVisible(false);
+        this.discardIcon.setVisible(true);
+        this.textBox.setVisible(true);
+        this.textBox.setText(i18next.t("partyUiHandler:DISCARD"));
+        this.setPosition(
+          globalScene.currentBattle.double ? 64 : 60,
+          globalScene.currentBattle.double ? -48 : -globalScene.game.canvas.height / 15 - 1,
+        );
+        this.discardIcon.displayWidth = this.textBox.text.length * 9 + 3;
+        break;
+    }
+  }
+
+  clear() {
+    this.setActive(false).setVisible(false);
+    this.transferIcon.setVisible(false);
+    this.discardIcon.setVisible(false);
+    this.textBox.setVisible(false);
+  }
+}

test/ui/item-manage-button.test.ts

@@ -0,0 +1,172 @@
+import { BerryType } from "#enums/berry-type";
+import { Button } from "#enums/buttons";
+import { MoveId } from "#enums/move-id";
+import { SpeciesId } from "#enums/species-id";
+import { UiMode } from "#enums/ui-mode";
+import type { Pokemon } from "#field/pokemon";
+import { GameManager } from "#test/test-utils/game-manager";
+import type { ModifierSelectUiHandler } from "#ui/modifier-select-ui-handler";
+import type { PartyUiHandler } from "#ui/party-ui-handler";
+import Phaser from "phaser";
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
+
+describe("UI - Transfer Items", () => {
+  let phaserGame: Phaser.Game;
+  let game: GameManager;
+
+  beforeAll(() => {
+    phaserGame = new Phaser.Game({
+      type: Phaser.HEADLESS,
+    });
+  });
+
+  afterEach(() => {
+    game.phaseInterceptor.restoreOg();
+  });
+
+  beforeEach(async () => {
+    game = new GameManager(phaserGame);
+    game.override
+      .battleStyle("single")
+      .startingLevel(100)
+      .startingHeldItems([
+        { name: "BERRY", count: 1, type: BerryType.SITRUS },
+        { name: "BERRY", count: 2, type: BerryType.APICOT },
+        { name: "BERRY", count: 2, type: BerryType.LUM },
+      ])
+      .enemySpecies(SpeciesId.MAGIKARP)
+      .enemyMoveset(MoveId.SPLASH);
+
+    await game.classicMode.startBattle([SpeciesId.RAYQUAZA, SpeciesId.RAYQUAZA, SpeciesId.RAYQUAZA]);
+
+    game.move.use(MoveId.DRAGON_CLAW);
+
+    await game.phaseInterceptor.to("SelectModifierPhase");
+  });
+
+  it("manage button exists in the proper screen", async () => {
+    let handlerLength: Phaser.GameObjects.GameObject[] | undefined;
+
+    await new Promise<void>(resolve => {
+      //select manage items menu
+      game.onNextPrompt("SelectModifierPhase", UiMode.MODIFIER_SELECT, async () => {
+        await new Promise(r => setTimeout(r, 100));
+        const handler = game.scene.ui.getHandler() as ModifierSelectUiHandler;
+
+        handler.processInput(Button.DOWN);
+        handler.setCursor(1);
+        handler.processInput(Button.ACTION);
+      });
+
+      game.onNextPrompt("SelectModifierPhase", UiMode.PARTY, async () => {
+        await new Promise(r => setTimeout(r, 100));
+        const handler = game.scene.ui.getHandler() as PartyUiHandler;
+
+        handler.processInput(Button.DOWN);
+        handler.processInput(Button.ACTION);
+        handlerLength = handler.optionsContainer.list;
+
+        handler.processInput(Button.CANCEL);
+
+        resolve();
+      });
+    });
+
+    expect(handlerLength).toHaveLength(0); // should select manage button, which has no menu
+  });
+
+  it("manage button doesn't exist in the other screens", async () => {
+    let handlerLength: Phaser.GameObjects.GameObject[] | undefined;
+
+    await new Promise<void>(resolve => {
+      game.onNextPrompt("SelectModifierPhase", UiMode.MODIFIER_SELECT, async () => {
+        await new Promise(r => setTimeout(r, 100));
+        const handler = game.scene.ui.getHandler() as ModifierSelectUiHandler;
+
+        handler.processInput(Button.DOWN);
+        handler.setCursor(2);
+        handler.processInput(Button.ACTION);
+      });
+
+      game.onNextPrompt("SelectModifierPhase", UiMode.PARTY, async () => {
+        await new Promise(r => setTimeout(r, 100));
+        const handler = game.scene.ui.getHandler() as PartyUiHandler;
+
+        handler.processInput(Button.DOWN);
+        handler.processInput(Button.ACTION);
+        handlerLength = handler.optionsContainer.list;
+
+        handler.processInput(Button.CANCEL);
+        handler.processInput(Button.CANCEL);
+
+        resolve();
+      });
+    });
+
+    expect(handlerLength).toHaveLength(6); // should select 2nd pokemon (length is 5 options + image)
+  });
+
+  // Test that the manage button actually discards items, needs proofreading
+  it("should discard items when button is selected", async () => {
+    let pokemon: Pokemon | undefined;
+
+    await new Promise<void>(resolve => {
+      game.onNextPrompt("SelectModifierPhase", UiMode.MODIFIER_SELECT, async () => {
+        await new Promise(r => setTimeout(r, 100));
+        const handler = game.scene.ui.getHandler() as ModifierSelectUiHandler;
+
+        handler.processInput(Button.DOWN);
+        handler.setCursor(1);
+        handler.processInput(Button.ACTION);
+      });
+      game.onNextPrompt("SelectModifierPhase", UiMode.PARTY, async () => {
+        await new Promise(r => setTimeout(r, 100));
+        const handler = game.scene.ui.getHandler() as PartyUiHandler;
+
+        // Enter discard mode and select first party member
+        handler.setCursor(7);
+        handler.processInput(Button.ACTION);
+        handler.setCursor(0);
+        handler.processInput(Button.ACTION);
+        pokemon = game.field.getPlayerPokemon();
+
+        resolve();
+      });
+    });
+
+    expect(pokemon).toBeDefined();
+    if (pokemon) {
+      expect(pokemon.getHeldItems()).toHaveLength(3);
+      expect(pokemon.getHeldItems().map(h => h.stackCount)).toEqual([1, 2, 2]);
+    }
+
+    await new Promise<void>(resolve => {
+      game.onNextPrompt("SelectModifierPhase", UiMode.PARTY, async () => {
+        await new Promise(r => setTimeout(r, 100));
+        const handler = game.scene.ui.getHandler() as PartyUiHandler;
+        handler.processInput(Button.ACTION);
+        resolve();
+      });
+    });
+
+    await new Promise<void>(resolve => {
+      game.onNextPrompt("SelectModifierPhase", UiMode.PARTY, async () => {
+        await new Promise(r => setTimeout(r, 100));
+        const handler = game.scene.ui.getHandler() as PartyUiHandler;
+        handler.processInput(Button.ACTION);
+
+        pokemon = game.field.getPlayerPokemon();
+
+        handler.processInput(Button.CANCEL);
+        resolve();
+      });
+    });
+
+    expect(pokemon).toBeDefined();
+    if (pokemon) {
+      // Sitrus berry was discarded, leaving 2 stacks of 2 berries behind
+      expect(pokemon.getHeldItems()).toHaveLength(2);
+      expect(pokemon.getHeldItems().map(h => h.stackCount)).toEqual([2, 2]);
+    }
+  });
+});