Add disabled attribute support for form controls

spinygui.core/src/main/java/com/spinyowl/spinygui/core/node/ButtonElement.java

@@ -1,5 +1,6 @@
 package com.spinyowl.spinygui.core.node;
 
+import static com.spinyowl.spinygui.core.node.NodeBuilder.ATTR_DISABLED;
 import static com.spinyowl.spinygui.core.node.NodeBuilder.ATTR_TYPE;
 import static com.spinyowl.spinygui.core.node.NodeBuilder.NODE_BUTTON;
 import static com.spinyowl.spinygui.core.node.NodeBuilder.TYPE_BUTTON;
@@ -37,6 +38,11 @@ public void type(String type) {
     this.type = type == null || type.isBlank() ? TYPE_SUBMIT : type;
   }
 
+  @Override
+  public boolean disabled() {
+    return hasAttribute(ATTR_DISABLED);
+  }
+
   public boolean plainButton() {
     return TYPE_BUTTON.equalsIgnoreCase(type);
   }
@@ -50,6 +56,6 @@ public boolean resetButton() {
   }
 
   public boolean activatable() {
-    return plainButton() || submitButton() || resetButton();
+    return !disabled() && (plainButton() || submitButton() || resetButton());
   }
 }

spinygui.core/src/main/java/com/spinyowl/spinygui/core/node/Element.java

@@ -114,6 +114,11 @@ public boolean hasAttribute(String attribute) {
     return attributes.containsKey(attribute);
   }
 
+  /** Returns whether this element is a control disabled by its {@code disabled} attribute. */
+  public boolean disabled() {
+    return false;
+  }
+
   @Override
   public void removeAttribute(String attribute) {
     attributes.remove(attribute);

spinygui.core/src/main/java/com/spinyowl/spinygui/core/node/InputElement.java

@@ -1,5 +1,6 @@
 package com.spinyowl.spinygui.core.node;
 
+import static com.spinyowl.spinygui.core.node.NodeBuilder.ATTR_DISABLED;
 import static com.spinyowl.spinygui.core.node.NodeBuilder.ATTR_TYPE;
 import static com.spinyowl.spinygui.core.node.NodeBuilder.ATTR_VALUE;
 import static com.spinyowl.spinygui.core.node.NodeBuilder.NODE_INPUT;
@@ -115,6 +116,11 @@ public void textScrollLeft(float textScrollLeft) {
     this.textScrollLeft = Math.max(0, textScrollLeft);
   }
 
+  @Override
+  public boolean disabled() {
+    return hasAttribute(ATTR_DISABLED);
+  }
+
   public boolean textInput() {
     return TYPE_TEXT.equalsIgnoreCase(type);
   }

spinygui.core/src/main/java/com/spinyowl/spinygui/core/node/NodeBuilder.java

@@ -11,6 +11,7 @@ public final class NodeBuilder {
   public static final String ATTR_TYPE = "type";
   public static final String ATTR_NAME = "name";
   public static final String ATTR_VALUE = "value";
+  public static final String ATTR_DISABLED = "disabled";
   public static final String ATTR_ROWS = "rows";
   public static final String ATTR_COLS = "cols";
 
@@ -99,6 +100,11 @@ public static Attribute value(String value) {
     return attr(ATTR_VALUE, value);
   }
 
+  /** Creates a boolean {@code disabled} attribute. */
+  public static Attribute disabled() {
+    return attr(ATTR_DISABLED, "");
+  }
+
   public static Attribute rows(String value) {
     return attr(ATTR_ROWS, value);
   }

spinygui.core/src/main/java/com/spinyowl/spinygui/core/node/TextareaElement.java

@@ -1,5 +1,6 @@
 package com.spinyowl.spinygui.core.node;
 
+import static com.spinyowl.spinygui.core.node.NodeBuilder.ATTR_DISABLED;
 import static com.spinyowl.spinygui.core.node.NodeBuilder.NODE_TEXTAREA;
 
 import java.util.Map;
@@ -105,6 +106,11 @@ public void textScrollLeft(float textScrollLeft) {
     this.textScrollLeft = Math.max(0, textScrollLeft);
   }
 
+  @Override
+  public boolean disabled() {
+    return hasAttribute(ATTR_DISABLED);
+  }
+
   private int clampTextIndex(int index) {
     return TextIndexNormalizer.clampAndSnapBackward(value, index);
   }

spinygui.core/src/main/java/com/spinyowl/spinygui/core/parser/impl/css/visitor/SelectorVisitor.java

@@ -14,6 +14,7 @@
 import com.spinyowl.spinygui.core.style.stylesheet.selector.combinator.DescendantSelector;
 import com.spinyowl.spinygui.core.style.stylesheet.selector.combinator.GeneralSiblingSelector;
 import com.spinyowl.spinygui.core.style.stylesheet.selector.pseudoclass.ActiveSelector;
+import com.spinyowl.spinygui.core.style.stylesheet.selector.pseudoclass.DisabledSelector;
 import com.spinyowl.spinygui.core.style.stylesheet.selector.pseudoclass.FocusSelector;
 import com.spinyowl.spinygui.core.style.stylesheet.selector.pseudoclass.HoverSelector;
 import com.spinyowl.spinygui.core.style.stylesheet.selector.pseudoelement.AfterSelector;
@@ -99,6 +100,10 @@ public Selector visitPseudo(PseudoContext ctx) {
       return new ActiveSelector();
     }
 
+    if ("disabled".equals(selectorName)) {
+      return new DisabledSelector();
+    }
+
     if ("before".equals(selectorName)) {
       return new BeforeSelector();
     }

spinygui.core/src/main/java/com/spinyowl/spinygui/core/style/stylesheet/selector/pseudoclass/DisabledSelector.java

@@ -0,0 +1,18 @@
+package com.spinyowl.spinygui.core.style.stylesheet.selector.pseudoclass;
+
+import com.spinyowl.spinygui.core.node.Element;
+import com.spinyowl.spinygui.core.style.stylesheet.selector.PseudoClassSelector;
+
+/** Matches supported form controls that currently have the boolean {@code disabled} attribute. */
+public class DisabledSelector implements PseudoClassSelector {
+
+  @Override
+  public boolean test(Element element) {
+    return element.disabled();
+  }
+
+  @Override
+  public String toString() {
+    return ":disabled";
+  }
+}

spinygui.core/src/main/java/com/spinyowl/spinygui/core/system/event/listener/SystemCharEventListener.java

@@ -62,7 +62,7 @@ public void processWithImpact(
   private void processInternal(
       SystemCharEvent event, Frame frame, InputProcessingBatch batch) {
     var focusedElement = frame.getFocusedElement();
-    if (focusedElement == null) {
+    if (focusedElement == null || focusedElement.disabled()) {
       return;
     }
 

spinygui.core/src/main/java/com/spinyowl/spinygui/core/system/event/listener/SystemKeyEventListener.java

@@ -80,6 +80,10 @@ public void processWithImpact(
   private void processInternal(
       SystemKeyEvent event, Frame frame, InputProcessingBatch batch) {
     var element = frame.getFocusedElement();
+    if (element != null && element.disabled()) {
+      element.pressed(false);
+      return;
+    }
     if (element == null && batch == null) {
       return;
     }

spinygui.core/src/main/java/com/spinyowl/spinygui/core/system/event/listener/SystemMouseClickEventListener.java

@@ -90,6 +90,16 @@ public void process(@NonNull SystemMouseClickEvent event, @NonNull Frame frame)
       processWithNoTarget(event, frame, focusedElement, currentCursorPosition);
     } else {
       target = buttonOwner(target);
+      if (target.disabled()) {
+        target.pressed(false);
+        if (event.action() == RELEASE && focusedElement != null && focusedElement != target) {
+          focusedElement.pressed(false);
+          if (!focusedElement.disabled()) {
+            generateReleaseEvent(event, frame, focusedElement, currentCursorPosition);
+          }
+        }
+        return;
+      }
       processWithExistingTarget(event, frame, focusedElement, currentCursorPosition, target);
     }
   }
@@ -291,7 +301,7 @@ private void generateActionEvent(Frame frame, Element target) {
 
   private boolean activatable(Element target) {
     return target instanceof ButtonElement button && button.activatable()
-        || target instanceof InputElement input && input.buttonInput();
+        || target instanceof InputElement input && input.buttonInput() && !input.disabled();
   }
 
   private Element buttonOwner(Element target) {

spinygui.core/src/main/java/com/spinyowl/spinygui/core/system/input/ButtonBehavior.java

@@ -14,12 +14,16 @@ public boolean handleKey(ButtonElement button, KeyCode keyCode, KeyAction action
   }
 
   public boolean handleKey(InputElement input, KeyCode keyCode, KeyAction action) {
-    return handleKey(input, input.buttonInput(), keyCode, action);
+    return handleKey(input, input.buttonInput() && !input.disabled(), keyCode, action);
   }
 
   private boolean handleKey(
       Element element, boolean activatable, KeyCode keyCode, KeyAction action) {
-    if (!activatable || !activationKey(keyCode)) {
+    if (!activatable) {
+      element.pressed(false);
+      return false;
+    }
+    if (!activationKey(keyCode)) {
       return false;
     }
 

spinygui.core/src/test/java/com/spinyowl/spinygui/core/node/DisabledAttributeTest.java

@@ -0,0 +1,57 @@
+package com.spinyowl.spinygui.core.node;
+
+import static com.spinyowl.spinygui.core.node.NodeBuilder.ATTR_DISABLED;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.TYPE_BUTTON;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.attrs;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.button;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.disabled;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.div;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.input;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.textarea;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.type;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class DisabledAttributeTest {
+
+  @Test
+  void disabledAttributeMarksSupportedControlsDisabled() {
+    ButtonElement button = button(attrs(disabled()));
+    InputElement input = input(attrs(disabled()));
+    TextareaElement textarea = textarea(attrs(disabled()), "value");
+
+    assertTrue(button.disabled());
+    assertTrue(input.disabled());
+    assertTrue(textarea.disabled());
+  }
+
+  @Test
+  void disabledAttributeUsesBooleanPresenceSemantics() {
+    InputElement input = input();
+
+    input.setAttribute(ATTR_DISABLED, "false");
+    assertTrue(input.disabled());
+
+    input.removeAttribute(ATTR_DISABLED);
+    assertFalse(input.disabled());
+  }
+
+  @Test
+  void unsupportedElementDoesNotBecomeDisabled() {
+    Element element = div(attrs(disabled()));
+
+    assertFalse(element.disabled());
+  }
+
+  @Test
+  void disabledButtonIsNotActivatable() {
+    ButtonElement button = button(attrs(disabled(), type(TYPE_BUTTON)));
+
+    assertFalse(button.activatable());
+
+    button.removeAttribute(ATTR_DISABLED);
+    assertTrue(button.activatable());
+  }
+}

spinygui.core/src/test/java/com/spinyowl/spinygui/core/style/stylesheet/selector/pseudoclass/DisabledSelectorTest.java

@@ -0,0 +1,32 @@
+package com.spinyowl.spinygui.core.style.stylesheet.selector.pseudoclass;
+
+import static com.spinyowl.spinygui.core.node.NodeBuilder.attrs;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.button;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.disabled;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.div;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.input;
+import static com.spinyowl.spinygui.core.node.NodeBuilder.textarea;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class DisabledSelectorTest {
+
+  private final DisabledSelector selector = new DisabledSelector();
+
+  @Test
+  void matchesDisabledSupportedControls() {
+    assertTrue(selector.test(button(attrs(disabled()))));
+    assertTrue(selector.test(input(attrs(disabled()))));
+    assertTrue(selector.test(textarea(attrs(disabled()), "value")));
+  }
+
+  @Test
+  void doesNotMatchEnabledOrUnsupportedElements() {
+    assertFalse(selector.test(button()));
+    assertFalse(selector.test(input()));
+    assertFalse(selector.test(textarea()));
+    assertFalse(selector.test(div(attrs(disabled()))));
+  }
+}