Add observable properties and narration support (#136)

* Add focused narration support

* yes!

* More work on hovering and observables

* Fix WWidget.setHovered javadoc

* Document ObservableProperty.add/removeListener

* Add observable views

* Fix ObservableView.ChangeListener javadoc

* More JD!

* Add taglet for listing observable properties

Overkill? Yep. Still fancy? Absolutely!

* Fix narration element indices and more JD tricks

* Add slot hovering narration

* WItemSlot.getExtraNarrationMessage -> getNarrationName, make public API

* Remove the binding functionality of observable properties

This is required for having proper change listeners.

* Add ObservableView.hasValue

* Add some utility methods to ObservableView

* Clarify ObservableView.ChangeListener parameters

* Remove properties tag from WButton javadoc

3 files changed, 210 insertions, 0 deletions

diff --git a/javadoc/build.gradle b/javadoc/build.gradle
new file mode 100644
index 0000000..e8300bb
--- /dev/null
+++ b/javadoc/build.gradle
@@ -0,0 +1,6 @@
+plugins {
+	id 'java'
+}
+
+sourceCompatibility = rootProject.sourceCompatibility
+targetCompatibility = rootProject.targetCompatibility
diff --git a/javadoc/src/main/java/io/github/cottonmc/cotton/gui/jd/ExperimentalTaglet.java b/javadoc/src/main/java/io/github/cottonmc/cotton/gui/jd/ExperimentalTaglet.java
new file mode 100644
index 0000000..dbd2391
--- /dev/null
+++ b/javadoc/src/main/java/io/github/cottonmc/cotton/gui/jd/ExperimentalTaglet.java
@@ -0,0 +1,30 @@
+package io.github.cottonmc.cotton.gui.jd;
+
+import com.sun.source.doctree.DocTree;
+import jdk.javadoc.doclet.Taglet;
+
+import java.util.List;
+import java.util.Set;
+import javax.lang.model.element.Element;
+
+public class ExperimentalTaglet implements Taglet {
+	@Override
+	public Set<Location> getAllowedLocations() {
+		return Set.of(Location.values());
+	}
+
+	@Override
+	public boolean isInlineTag() {
+		return false;
+	}
+
+	@Override
+	public String getName() {
+		return "experimental";
+	}
+
+	@Override
+	public String toString(List<? extends DocTree> tags, Element element) {
+		return "<dt>Experimental API:</dt><dd>Might be modified or removed without prior notice until stabilised.</dd>";
+	}
+}
diff --git a/javadoc/src/main/java/io/github/cottonmc/cotton/gui/jd/PropertyTaglet.java b/javadoc/src/main/java/io/github/cottonmc/cotton/gui/jd/PropertyTaglet.java
new file mode 100644
index 0000000..163f1d6
--- /dev/null
+++ b/javadoc/src/main/java/io/github/cottonmc/cotton/gui/jd/PropertyTaglet.java
@@ -0,0 +1,174 @@
+package io.github.cottonmc.cotton.gui.jd;
+
+import com.sun.source.doctree.DocTree;
+import com.sun.source.doctree.TextTree;
+import com.sun.source.util.DocTrees;
+import com.sun.source.util.SimpleDocTreeVisitor;
+import jdk.javadoc.doclet.Doclet;
+import jdk.javadoc.doclet.DocletEnvironment;
+import jdk.javadoc.doclet.Taglet;
+
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import javax.lang.model.element.Element;
+import javax.lang.model.element.ElementKind;
+import javax.lang.model.element.ExecutableElement;
+import javax.lang.model.element.TypeElement;
+import javax.lang.model.type.DeclaredType;
+import javax.lang.model.type.TypeVisitor;
+import javax.lang.model.util.ElementKindVisitor8;
+import javax.lang.model.util.SimpleTypeVisitor8;
+
+public class PropertyTaglet implements Taglet {
+	private static final Pattern PROPERTY_METHOD = Pattern.compile("^(.+)Property$");
+	private static final String OBSERVABLE_PROPERTY = "io.github.cottonmc.cotton.gui.widget.data.ObservableProperty";
+	private DocTrees docTrees;
+
+	@Override
+	public void init(DocletEnvironment env, Doclet doclet) {
+		docTrees = env.getDocTrees();
+	}
+
+	@Override
+	public Set<Location> getAllowedLocations() {
+		return Set.of(Location.TYPE);
+	}
+
+	@Override
+	public boolean isInlineTag() {
+		return false;
+	}
+
+	@Override
+	public String getName() {
+		return "properties";
+	}
+
+	@Override
+	public String toString(List<? extends DocTree> tags, Element element) {
+		if (!((element.getKind().isClass() || element.getKind().isInterface()) && element instanceof TypeElement type)) {
+			throw new IllegalArgumentException("Not a type: " + element);
+		}
+
+		List<PropertyEntry> myEntries = scan(type);
+		StringBuilder builder = new StringBuilder();
+
+		if (!myEntries.isEmpty()) {
+			builder.append("<div class=\"caption\"><span>Properties</span></div>");
+			builder.append("<div class=\"summary-table two-column-summary\">");
+			builder.append("<div class=\"table-header col-first\">Property</div>");
+			builder.append("<div class=\"table-header col-last\">Description</div>");
+
+			for (int i = 0; i < myEntries.size(); i++) {
+				PropertyEntry entry = myEntries.get(i);
+				String rowClass = (i % 2 == 0) ? "even-row-color" : "odd-row-color";
+				builder.append("<div class=\"col-first ").append(rowClass).append("\"><code><span class=\"member-name-link\">");
+				builder.append("<a href=\"#").append(entry.name).append("Property()\">").append(entry.name).append("</a>");
+				builder.append("</span></code></div>");
+				builder.append("<div class=\"col-last ").append(rowClass).append("\">").append(entry.doc).append("</div>");
+			}
+
+			builder.append("</div>");
+		}
+
+		Map<String, List<PropertyEntry>> inheritedProperties = new LinkedHashMap<>();
+		scanParents(type, inheritedProperties);
+
+		inheritedProperties.forEach((name, entries) -> {
+			if (!entries.isEmpty()) {
+				builder.append("<dt>Properties from <code>").append(name).append("</code></dt>");
+				builder.append("<dd>");
+				builder.append(entries.stream().map(entry -> "<code>" + entry.name + "</code>").collect(Collectors.joining(", ")));
+				builder.append("</dd>");
+			}
+		});
+
+		return builder.toString();
+	}
+
+	private static String getClassName(TypeElement cl) {
+		return cl.getQualifiedName().toString();
+	}
+
+	private List<PropertyEntry> scan(TypeElement cl) {
+		// Java classes don't have LibGui properties (yet? 😳)
+		if (getClassName(cl).startsWith("java.")) return List.of();
+
+		return cl.getEnclosedElements().stream()
+				.filter(el -> el.getKind() == ElementKind.METHOD)
+				.map(el -> (ExecutableElement) el)
+				.filter(el -> el.getReturnType().accept(new ObservableTypeFilter(), null))
+				.map(el -> {
+					Matcher matcher = PROPERTY_METHOD.matcher(el.getSimpleName());
+
+					if (matcher.matches()) {
+						String doc = docTrees.getDocCommentTree(el).getFirstSentence().stream()
+								.map(tree -> tree.accept(new SimpleDocTreeVisitor<String, Void>() {
+									@Override
+									public String visitText(TextTree node, Void o) {
+										return node.getBody();
+									}
+								}, null))
+								.filter(Objects::nonNull)
+								.findAny().orElse("");
+
+						return new PropertyEntry(matcher.group(1), doc);
+					}
+
+					return null;
+				})
+				.filter(Objects::nonNull)
+				.sorted()
+				.collect(Collectors.toList());
+	}
+
+	private void scanParents(TypeElement cl, Map<String, List<PropertyEntry>> inheritedProperties) {
+		TypeVisitor<Void, Void> typeVisitor = new SimpleTypeVisitor8<>() {
+			@Override
+			public Void visitDeclared(DeclaredType t, Void o) {
+				return t.asElement().accept(new ElementKindVisitor8<>() {
+					@Override
+					public Void visitType(TypeElement e, Object o) {
+						String fqn = e.getQualifiedName().toString();
+						inheritedProperties.put(fqn, scan(e));
+						scanParents(e, inheritedProperties);
+						return null;
+					}
+				}, null);
+			}
+		};
+
+		cl.getSuperclass().accept(typeVisitor, null);
+		cl.getInterfaces().forEach(itf -> itf.accept(typeVisitor, null));
+	}
+
+	private static final class ObservableTypeFilter extends SimpleTypeVisitor8<Boolean, Void> {
+		ObservableTypeFilter() {
+			super(false);
+		}
+
+		@Override
+		public Boolean visitDeclared(DeclaredType t, Void v) {
+			Element type = t.asElement();
+
+			if (type.getKind() == ElementKind.CLASS) {
+				return ((TypeElement) type).getQualifiedName().contentEquals(OBSERVABLE_PROPERTY);
+			}
+
+			return false;
+		}
+	}
+
+	private record PropertyEntry(String name, String doc) implements Comparable<PropertyEntry> {
+		@Override
+		public int compareTo(PropertyEntry o) {
+			return name.compareTo(o.name);
+		}
+	}
+}