feat: create an unparser for variation diffs

Author: eugen-shulimov

src/main/java/org/variantsync/diffdetective/variation/VariationUnparser.java

@@ -1,30 +1,85 @@
 package org.variantsync.diffdetective.variation;
 
+import java.io.IOException;
+import java.util.List;
 import java.util.Stack;
+import java.util.function.Function;
+import org.eclipse.jgit.diff.DiffAlgorithm.SupportedAlgorithm;
+import org.variantsync.diffdetective.variation.diff.Time;
+import org.variantsync.diffdetective.variation.diff.VariationDiff;
+import org.variantsync.diffdetective.variation.diff.construction.JGitDiff;
 import org.variantsync.diffdetective.variation.tree.VariationTree;
 import org.variantsync.diffdetective.variation.tree.VariationTreeNode;
 
 public class VariationUnparser {
-    public static String variationTreeUnparser(VariationTree<? extends Label> tree) {
-        StringBuilder result = new StringBuilder();
-        Stack<VariationTreeNode<? extends Label>> stack = new Stack<>();
-        for (int i = tree.root().getChildren().size() - 1; i >= 0; i--) {
-            stack.push(tree.root().getChildren().get(i));
-        }
-        while (!stack.empty()) {
-            VariationTreeNode<? extends Label> node = stack.pop();
-            for (String line : node.getLabel().getLines()) {
-                result.append(line);
-                result.append("\n");
-            }
-            if (node.isIf()) {
-                stack.push(new VariationTreeNode<>(NodeType.ARTIFACT, null, null,
-                        DiffLinesLabel.withInvalidLineNumbers(node.getEndIf())));
+    /**
+     * Unparse VariationTrees to Text/String
+     *
+     * @param tree         VariationTree, that be unparsed
+     * @param linesToLabel Function, that return list of String and has a Class T
+     * @return String, the result of unparsing
+     * @param <T> that implements Label
+     */
+    public static <T extends Label> String variationTreeUnparser(VariationTree<T> tree, Function<List<String>, T> linesToLabel) {
+        if (!tree.root().getChildren().isEmpty()) {
+            StringBuilder result = new StringBuilder();
+            Stack<VariationTreeNode<T>> stack = new Stack<>();
+            for (int i = tree.root().getChildren().size() - 1; i >= 0; i--) {
+                stack.push(tree.root().getChildren().get(i));
             }
-            for (int i = node.getChildren().size() - 1; i >= 0; i--) {
-                stack.push(node.getChildren().get(i));
+            while (!stack.empty()) {
+                VariationTreeNode<T> node = stack.pop();
+                for (String line : node.getLabel().getLines()) {
+                    result.append(line);
+                    result.append("\n");
+                }
+                if (node.isIf()) {
+                    stack.push(new VariationTreeNode<>(NodeType.ARTIFACT, null, null,
+                            linesToLabel.apply(node.getEndIf())));
+                }
+                for (int i = node.getChildren().size() - 1; i >= 0; i--) {
+                    stack.push(node.getChildren().get(i));
+                }
             }
+            return result.substring(0, result.length() - 1);
+        } else {
+            return "";
         }
-        return result.substring(0, result.length() - 1);
+    }
+
+    /**
+     * Unparse VariationTrees to Text/String
+     *
+     * @param tree VariationTree, that be unparsed
+     * @return String, the result of unparsing
+     */
+    public static String variationTreeUnparser(VariationTree<DiffLinesLabel> tree) {
+        return variationTreeUnparser(tree, DiffLinesLabel::withInvalidLineNumbers);
+    }
+
+    /**
+     * Unparse VariationDiffs to Text/String
+     *
+     * @param diff         VariationDiff, that be unparsed
+     * @param linesToLabel Function, that return list of String and has a Class T
+     * @return String, the result of unparsing
+     * @param <T> that implements Label
+     * @throws IOException
+     */
+    public static <T extends Label> String variationDiffUnparser(VariationDiff<T> diff, Function<List<String>, T> linesToLabel) throws IOException {
+        String tree1 = variationTreeUnparser(diff.project(Time.BEFORE), linesToLabel);
+        String tree2 = variationTreeUnparser(diff.project(Time.AFTER), linesToLabel);
+        return JGitDiff.textDiff(tree1, tree2, SupportedAlgorithm.MYERS);
+    }
+
+    /**
+     * Unparse VariationDiffs to Text/String
+     *
+     * @param diff VariationDiff, that be unparsed
+     * @return String, the result of unparsing
+     * @throws IOException
+     */
+    public static String variationDiffUnparser(VariationDiff<DiffLinesLabel> diff) throws IOException {
+        return variationDiffUnparser(diff, DiffLinesLabel::withInvalidLineNumbers);
     }
 }