package de.synolo.lib.fw.cmd;

import java.util.Stack;

import javafx.beans.property.ReadOnlyBooleanProperty;
import javafx.beans.property.ReadOnlyBooleanWrapper;

public class UndoManager {
	
	private Stack<Command> undoStack;
	private Stack<Command> redoStack;

	private ReadOnlyBooleanWrapper undoAvailalableProperty = new ReadOnlyBooleanWrapper(false);
	private ReadOnlyBooleanWrapper redoAvailalableProperty = new ReadOnlyBooleanWrapper(false);
	
	private int max;
	
	public UndoManager(int maxCommands) {
		this.max = maxCommands;
		this.undoStack = new Stack<>();
		this.redoStack = new Stack<>();
	}
	
	public UndoManager() {
		this(100);
	}
	
	public int getMaxCommands() { return this.max; }
	public void setMaxCommands(int max) { this.max = max; }
	
	public boolean isUndoAvailable() {
		return !this.undoStack.isEmpty();
	}
	public ReadOnlyBooleanProperty undoAvailableProperty() { return this.undoAvailalableProperty.getReadOnlyProperty(); } 
	
	public boolean isRedoAvailable() {
		return !this.redoStack.isEmpty();
	}
	public ReadOnlyBooleanProperty redoAvailableProperty() { return this.redoAvailalableProperty.getReadOnlyProperty(); }
	
	public void execute(Command cmd) {
		Command last = null;
		
		if(!this.undoStack.isEmpty() && (last = this.undoStack.peek()) != null) {
			if(last.isCollapsable(cmd)) {
				last.collapse(cmd);
				return;
			}else {
				this.redoStack.clear();
				this.undoStack.push(cmd);
			}
		}else if(cmd.isUndoable()) {
			this.redoStack.clear();
			this.undoStack.push(cmd);
		}
		if(this.undoStack.size() > this.max) {
			this.undoStack.remove(0);
		}
		cmd.execute();
		update();

	}
	
	public void undo() {
		System.out.println("undo...");
		if(isUndoAvailable()) {
			Command cmd = this.undoStack.pop();
			this.redoStack.push(cmd);
			cmd.undo();
		}
		update();
	}
	
	public void redo() {
		if(isRedoAvailable()) {
			Command cmd = this.redoStack.pop();
			this.undoStack.push(cmd);
			cmd.redo();
		}
		update();
	}
	
	private void update() {
		this.undoAvailalableProperty.set(isUndoAvailable());
		this.redoAvailalableProperty.set(isRedoAvailable());
		System.out.println(this.undoStack);
	}
	
	
}