feat: IndexFormat

Author: pmbittner

src/main/java/org/variantsync/diffdetective/variation/diff/serialize/nodeformat/IndexFormat.java

@@ -0,0 +1,27 @@
+package org.variantsync.diffdetective.variation.diff.serialize.nodeformat;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.variantsync.diffdetective.variation.Label;
+import org.variantsync.diffdetective.variation.diff.DiffNode;
+import org.variantsync.diffdetective.variation.diff.Time;
+import org.variantsync.functjonal.Cast;
+
+/**
+ * Labels nodes using their index in their parent list at all times.
+ */
+public class IndexFormat<L extends Label> implements DiffNodeLabelFormat<L> {
+    @Override
+    public String toLabel(final DiffNode<? extends L> n) {
+        final DiffNode<L> node = Cast.unchecked(n);
+        final Time[] allTimes = Time.values();
+        final List<String> values = new ArrayList<>(allTimes.length);
+        for (final Time t : allTimes) {
+            values.add(node.getDiffType().existsAtTime(t) && !node.isRoot()
+                ? Integer.toString(node.getParent(t).indexOfChild(node, t))
+                : "_");
+        }
+        return "(" + String.join(", ", values) + ")";
+    }
+}