Add = operator to crafting amount screen to only craft whats needed t…

…o reach a certain stored amount (#7382)

Closes #7156.

---------

Co-authored-by: Sebastian Hartte <shartte@users.noreply.github.com>

guidebook/items-blocks-machines/terminals.md

@@ -68,7 +68,8 @@ mouse/key shortcuts:
 
 *   Left-click grabs a stack, right-click grabs half a stack.
 *   If an item or fluid or etc. is able to be [autocrafted](../ae2-mechanics/autocrafting.md),
-    whatever you have bound to "pick block" (usually middle-click) brings up a UI to specify the amount to be crafted.
+    whatever you have bound to "pick block" (usually middle-click) brings up a UI to specify the amount to be crafted. You can also input formulas like `3*64/2`,
+    or type `=32` to only craft the number of items needed to reach 32 in your storage.
 *   Holding shift will freeze the displayed items in-place, stopping them from re-organizing themselves when quantities change or new items enter the system.
 *   Right-clicking with a bucket or other fluid container will deposit the fluid, left-clicking a fluid in the terminal with
     an empty fluid container will withdraw the fluid.

src/main/java/appeng/client/gui/MathExpressionParser.java

@@ -124,7 +124,7 @@ public static Optional<BigDecimal> parse(String expression, DecimalFormat decima
                         }
                     }
                 } else {
-                    if (number.size() < 1) {
+                    if (number.isEmpty()) {
                         return Optional.empty();
                     } else {
                         number.push(number.pop().negate());

src/main/java/appeng/client/gui/me/crafting/CraftAmountScreen.java

@@ -77,10 +77,11 @@ protected void updateBeforeRender() {
 
     private void confirm() {
         int amount = this.amountToCraft.getIntValue().orElse(0);
+        boolean craftMissingAmount = this.amountToCraft.startsWithEquals();
         if (amount <= 0) {
             return;
         }
-        menu.confirm(amount, hasShiftDown());
+        menu.confirm(amount, craftMissingAmount, hasShiftDown());
     }
 
 }

src/main/java/appeng/client/gui/widgets/NumberEntryWidget.java

@@ -234,6 +234,15 @@ public void populateScreen(Consumer<AbstractWidget> addWidget, Rect2i bounds, AE
         this.validate();
     }
 
+    /**
+     * Returns whether the text field begins with an equals sign. This is used by crafting request screens in order to
+     * request just enough of an item to bring the total stored amount to the input amount, rather than requesting the
+     * input amount itself.
+     */
+    public boolean startsWithEquals() {
+        return textField.getValue().startsWith("=");
+    }
+
     /**
      * Returns the integer value currently in the text-field, if it is a valid number and is within the allowed min/max
      * value.
@@ -296,7 +305,11 @@ private void addQty(long delta) {
      * Retrieves the numeric representation of the value entered by the user, if it is convertible.
      */
     private Optional<BigDecimal> getValueInternal() {
-        return MathExpressionParser.parse(textField.getValue(), decimalFormat);
+        var textValue = textField.getValue();
+        if (textValue.startsWith("=")) {
+            textValue = textValue.substring(1);
+        }
+        return MathExpressionParser.parse(textValue, decimalFormat);
     }
 
     /*

src/main/java/appeng/core/sync/packets/ConfirmAutoCraftPacket.java

@@ -29,28 +29,32 @@
 public class ConfirmAutoCraftPacket extends BasePacket {
 
     private final int amount;
+    private final boolean craftMissingAmount;
     private final boolean autoStart;
 
     public ConfirmAutoCraftPacket(FriendlyByteBuf stream) {
         this.autoStart = stream.readBoolean();
+        this.craftMissingAmount = stream.readBoolean();
         this.amount = stream.readInt();
     }
 
-    public ConfirmAutoCraftPacket(int craftAmt, boolean autoStart) {
+    public ConfirmAutoCraftPacket(int craftAmt, boolean craftMissingAmount, boolean autoStart) {
         this.amount = craftAmt;
+        this.craftMissingAmount = craftMissingAmount;
         this.autoStart = autoStart;
 
         final FriendlyByteBuf data = new FriendlyByteBuf(Unpooled.buffer());
         data.writeInt(this.getPacketID());
         data.writeBoolean(autoStart);
+        data.writeBoolean(craftMissingAmount);
         data.writeInt(this.amount);
         this.configureWrite(data);
     }
 
     @Override
     public void serverPacketData(ServerPlayer player) {
         if (player.containerMenu instanceof CraftAmountMenu menu) {
-            menu.confirm(amount, autoStart);
+            menu.confirm(amount, craftMissingAmount, autoStart);
         }
     }
 }

src/main/java/appeng/menu/me/crafting/CraftAmountMenu.java

@@ -24,7 +24,6 @@
 
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.entity.player.Inventory;
-import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.MenuType;
 import net.minecraft.world.level.Level;
 
@@ -103,31 +102,54 @@ private void setWhatToCraft(AEKey whatToCraft, int initialAmount) {
      * Confirms the craft request. If called client-side, automatically sends a packet to the server to perform the
      * action there instead.
      *
-     * @param amount    The number of items to craft.
-     * @param autoStart Start crafting immediately when the planning is done.
+     * @param amount             The number of items to craft.
+     * @param craftMissingAmount Craft only as much as needed to have <code>amount</code>
+     * @param autoStart          Start crafting immediately when the planning is done.
      */
-    public void confirm(int amount, boolean autoStart) {
+    public void confirm(int amount, boolean craftMissingAmount, boolean autoStart) {
         if (!isServerSide()) {
-            NetworkHandler.instance().sendToServer(new ConfirmAutoCraftPacket(amount, autoStart));
+            NetworkHandler.instance().sendToServer(new ConfirmAutoCraftPacket(amount, craftMissingAmount, autoStart));
             return;
         }
 
         if (this.whatToCraft == null) {
             return;
         }
 
+        if (craftMissingAmount) {
+            var host = getActionHost();
+            if (host != null) {
+                var node = host.getActionableNode();
+                if (node != null) {
+                    var storage = node.getGrid().getStorageService();
+                    var existingAmount = (int) Math.min(storage.getCachedInventory().get(whatToCraft),
+                            Integer.MAX_VALUE);
+                    if (existingAmount > amount) {
+                        amount = 0;
+                    } else {
+                        amount -= existingAmount;
+                    }
+                }
+            }
+        }
+
         var locator = getLocator();
         if (locator != null) {
-            Player player = this.getPlayerInventory().player;
-            MenuOpener.open(CraftConfirmMenu.TYPE, player, locator);
-
-            if (player.containerMenu instanceof CraftConfirmMenu ccc) {
-                ccc.setAutoStart(autoStart);
-                ccc.planJob(
-                        whatToCraft,
-                        amount,
-                        CalculationStrategy.REPORT_MISSING_ITEMS);
-                broadcastChanges();
+            var player = getPlayer();
+            if (amount > 0) {
+                MenuOpener.open(CraftConfirmMenu.TYPE, player, locator);
+
+                if (player.containerMenu instanceof CraftConfirmMenu ccc) {
+                    ccc.setAutoStart(autoStart);
+                    ccc.planJob(
+                            whatToCraft,
+                            amount,
+                            CalculationStrategy.REPORT_MISSING_ITEMS);
+                    broadcastChanges();
+                }
+            } else {
+                // When the amount to craft is 0, return to the previous menu without crafting
+                this.host.returnToMainMenu(player, this);
             }
         }
     }