stupid implementation of ctrl-z - just snapshoting whole project on e…

…very action. should probably do with diff and child field change listeners...

src/org/klesun_model/Explain.java

@@ -2,6 +2,7 @@
 
 import org.shmidusic.stuff.tools.Logger;
 
+import javax.xml.transform.Result;
 import java.util.concurrent.Callable;
 import java.util.function.Consumer;
 import java.util.function.Function;
@@ -76,13 +77,9 @@ public Explain<C> whenSuccess(Consumer<C> lambda) {
 		return ifSuccess(c -> { lambda.accept(c); return this; });
 	}
 
-    public Explain<C> whenFailure(Runnable onFailure) {
-        if (!this.isSuccess()) {
-            onFailure.run();
-        }
-        return this;
-
-    }
+    public <T> Explain<T> map(Function<C, T> mapLambda) {
+		return ifSuccess(result -> new Explain<T>(mapLambda.apply(result)));
+	}
 
 	public Explain<C> runIfSuccess(Runnable lambda) { return whenSuccess(r -> lambda.run()); }
 
@@ -114,9 +111,4 @@ public static <T, R> Function<T, Explain<R>> mkPred(Predicate<T> pred, Function<
 				? new Explain<>(func.apply(e))
 				: new Explain<>(false, "lox");
 	}
-
-    public Explain<C> whileIf(Supplier<Boolean> cond, Function<C, Explain<C>> iteration)
-    {
-        return cond.get() ? iteration.apply(this.data).whileIf(cond, iteration) : this;
-    }
 }

src/org/klesun_model/SnapshotStorage.java

@@ -0,0 +1,63 @@
+package org.klesun_model;
+
+// this class stores history to undo/redo
+// for now, i plan woodenly just store SheetMusic snapshot
+// after each handled event (if it differs from previous snapshot)
+
+import com.google.common.collect.EvictingQueue;
+import org.json.JSONObject;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+import java.util.Queue;
+import java.util.stream.StreamSupport;
+
+public class SnapshotStorage
+{
+	/** @TODO: storing snapshots is obviously not efficient (especially with the json string generation)
+	 * hang change listeners to fields of Models and store diff instead of snapshots */
+	final private Deque<JSONObject> snapshots = new ArrayDeque<>();
+	final private Deque<JSONObject> redoSnapshots = new ArrayDeque<>();
+
+	public void add(JSONObject snapshot)
+	{
+		if (snapshots.isEmpty() || !areEqual(snapshot, snapshots.peekLast())) {
+
+			snapshots.add(snapshot);
+			redoSnapshots.clear();
+
+			if (snapshots.size() > 20) {
+				snapshots.removeFirst();
+			}
+		}
+	}
+
+	public Explain<JSONObject> undo()
+	{
+		if (snapshots.size() >= 2) {
+			JSONObject current = snapshots.pollLast();
+			redoSnapshots.add(current);
+
+			return new Explain<>(snapshots.peekLast());
+		} else {
+			return new Explain<>(false, "Here History Starts");
+		}
+	}
+
+	public Explain<JSONObject> redo()
+	{
+		if (redoSnapshots.size() >= 2) {
+			JSONObject current = redoSnapshots.pollLast();
+			snapshots.add(current);
+
+			return new Explain<>(redoSnapshots.peekLast());
+		} else {
+			return new Explain<>(false, "Here History Ends");
+		}
+	}
+
+	// probably will be faster if we assert without string generation...
+	private static boolean areEqual(JSONObject a, JSONObject b)	{
+		return a.toString().equals(b.toString());
+	}
+}

src/org/shmidusic/MainPanel.java

@@ -1,5 +1,7 @@
 package org.shmidusic;
 
+import org.klesun_model.Explain;
+import org.klesun_model.SnapshotStorage;
 import org.shmidusic.sheet_music.staff.Staff;
 import org.shmidusic.sheet_music.SheetMusic;
 import org.shmidusic.sheet_music.SheetMusicComponent;
@@ -21,6 +23,7 @@ final public class MainPanel extends JPanel {
 
 	public SheetMusicComponent sheetContainer = new SheetMusicComponent(new SheetMusic(), this);
 	public Scroll sheetScroll = new Scroll(sheetContainer);
+	final public SnapshotStorage snapshotStorage = new SnapshotStorage();
 
 	final private PianoLayoutPanel pianoLayoutPanel;
 	final private JLabel statusField = new JLabel("status text");
@@ -54,7 +57,7 @@ public void replaceSheetMusic(SheetMusic sheetMusic)
 		this.add(sheetScroll = new Scroll(sheetContainer), BorderLayout.CENTER);
 		sheetScroll.getVerticalScrollBar().setUnitIncrement(Staff.SISDISPLACE);
 		sheetContainer.requestFocus();
-		DumpReceiver.eventHandler = (StaffHandler) sheetContainer.getFocusedChild().getHandler();
+		DumpReceiver.eventHandler = sheetContainer.getFocusedChild().getHandler();
 		// removing stupid built-ins
 		InputMap im = sheetScroll.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
 		im.put(KeyStroke.getKeyStroke("UP"), "none");
@@ -92,5 +95,13 @@ private String getStatusText()
 
 		return result;
 	}
+
+	public Explain undo() {
+		return snapshotStorage.undo().map(SheetMusic::new).whenSuccess(this::replaceSheetMusic);
+	}
+
+	public Explain redo() {
+		return snapshotStorage.redo().map(SheetMusic::new).whenSuccess(this::replaceSheetMusic);
+	}
 }
 

src/org/shmidusic/MajesticWindow.java

@@ -116,6 +116,7 @@ private JMenuItem makeActionMenuItem(Combo key, ContextAction action, Class<? ex
 			if (context != null) {
 				Explain explain = action.redo(context);
 				if (explain.isSuccess()) {
+					shmidusicPanel.snapshotStorage.add(context.getModel().getJsonRepresentation());
 					updateMenuBar();
 				} else {
 					JOptionPane.showMessageDialog(this, explain.getExplanation());

src/org/shmidusic/sheet_music/SheetMusic.java

@@ -1,5 +1,6 @@
 package org.shmidusic.sheet_music;
 
+import org.json.JSONObject;
 import org.klesun_model.AbstractModel;
 import org.klesun_model.field.Arr;
 import org.shmidusic.sheet_music.staff.Staff;
@@ -11,6 +12,11 @@ public class SheetMusic extends AbstractModel
 {
 	public Arr<Staff> staffList = add("staffList", new ArrayList<>(), Staff.class);
 
+	public SheetMusic(JSONObject state) {
+		this();
+		reconstructFromJson(state);
+	}
+
 	public SheetMusic()
 	{
 		Staff staff = new Staff();

src/org/shmidusic/sheet_music/SheetMusicComponent.java

@@ -12,6 +12,7 @@
 
 import javax.swing.*;
 import java.awt.*;
+import java.awt.event.KeyEvent;
 import java.util.*;
 import java.util.List;
 import java.util.function.Consumer;
@@ -57,13 +58,29 @@ public LinkedHashMap<Combo, ContextAction> getMyClassActionMap() {
 					.p(new Combo(ctrl, k.VK_I), mkFailableAction(FileProcessor::openMidi).setCaption("Open midi"))
 
 					.p(new Combo(ctrl, k.VK_E), mkFailableAction(FileProcessor::savePNG).setCaption("Export png"))
-						;
+
+					/** @debug */
+					.p(new Combo(ctrl, k.VK_Z), mkFailableAction(sm -> mainPanel.undo()).setCaption("Undo"))
+					.p(new Combo(ctrl, k.VK_Y), mkFailableAction(sm -> mainPanel.redo()).setCaption("Redo"))
+					;
 			}
 			public IComponent getContext() { return self; };
 		};
-		this.addKeyListener(Fp.onKey(e -> {
-			Explain result = handler.handleKey(new Combo(e));
-			if (!result.isSuccess() && !result.isImplicit()) {
+		this.addKeyListener(Fp.onKey(e ->
+		{
+			/** @TODO: same to menu */
+			Combo combo = new Combo(e);
+
+			Explain result = handler.handleKey(combo);
+			if (result.isSuccess()) {
+				// TODO: ctrl-z/ctrl-y probably should not be normal action at all!
+				if (!combo.equals(new Combo(KeyEvent.CTRL_MASK, KeyEvent.VK_Z)) &&
+					!combo.equals(new Combo(KeyEvent.CTRL_MASK, KeyEvent.VK_Y)))
+				{
+					mainPanel.snapshotStorage.add(sheetMusic.getJsonRepresentation());
+				}
+
+			} else if (!result.isImplicit()) {
 				JOptionPane.showMessageDialog(this, result.getExplanation());
 			}
 		}));