package dev.kske.undoredo.javafx;

import java.util.List;

import javafx.beans.property.*;

import dev.kske.undoredo.core.*;

/**
 * Wraps an ordinary change manager into an observable change manager, providing the required
 * properties for concrete implementations.
 * <p>
 * The properties have the same name as their corresponding {@code -property()} methods and can be
 * accessed reflectively from JavaFX, e.g. through
 * {@link javafx.beans.binding.Bindings#select(Object, String...)}. Alternatively, the property
 * names are available as constants.
 *
 * @param <C> the change type to store in this change manager
 * @param <M> the type of change manager to wrap
 * @author Kai S. K. Engelbart
 * @since 0.0.1
 */
public class ChangeManagerWrapper<C extends Change, M extends ChangeManager<C>>
	implements ObservableChangeManager<C> {

	public static final String	LAST_CHANGE			= "lastChange";
	public static final String	AT_MARKED_CHANGE	= "atMarkedChange";
	public static final String	UNDO_AVAILABLE		= "undoAvailable";
	public static final String	REDO_AVAILABLE		= "redoAvailable";

	protected final ReadOnlyObjectWrapper<C>	lastChange		=
		new ReadOnlyObjectWrapper<>(this, LAST_CHANGE);
	protected final ReadOnlyBooleanWrapper	atMarkedChange	=
		new ReadOnlyBooleanWrapper(this, AT_MARKED_CHANGE);
	protected final ReadOnlyBooleanWrapper	undoAvailable	=
		new ReadOnlyBooleanWrapper(this, UNDO_AVAILABLE);
	protected final ReadOnlyBooleanWrapper	redoAvailable	=
		new ReadOnlyBooleanWrapper(this, REDO_AVAILABLE);

	protected final M manager;

	/**
	 * Initializes a change manager wrapper.
	 *
	 * @param manager the change manager to wrap
	 * @since 0.0.1
	 */
	public ChangeManagerWrapper(M manager) {
		this.manager = manager;
		updateProperties();
	}

	@Override
	public boolean addChange(C change) {
		if (manager.addChange(change)) {
			updateProperties();
			return true;
		}
		return false;
	}

	@Override
	public boolean undo() {
		if (manager.undo()) {
			updateProperties();
			return true;
		}
		return false;
	}

	@Override
	public boolean redo() {
		if (manager.redo()) {
			updateProperties();
			return true;
		}
		return false;
	}

	@Override
	public void mark() {
		manager.mark();
		setAtMarkedChange(manager.isAtMarkedChange());
	}

	@Override
	public void unmark() {
		manager.unmark();
		setAtMarkedChange(manager.isAtMarkedChange());
	}

	/**
	 * Sets the values of all properties to those present in the wrapped change manager.
	 *
	 * @since 0.0.1
	 */
	private void updateProperties() {
		setLastChange(manager.getLastChange().orElse(null));
		setAtMarkedChange(manager.isAtMarkedChange());
		setUndoAvailable(manager.isUndoAvailable());
		setRedoAvailable(manager.isRedoAvailable());
	}

	@Override
	public final ReadOnlyObjectProperty<C> lastChangeProperty() {
		return lastChange.getReadOnlyProperty();
	}

	protected final void setLastChange(C lastChange) {
		this.lastChange.set(lastChange);
	}

	@Override
	public final ReadOnlyBooleanProperty atMarkedChangeProperty() {
		return atMarkedChange.getReadOnlyProperty();
	}

	protected final void setAtMarkedChange(boolean atMarkedChange) {
		this.atMarkedChange.set(atMarkedChange);
	}

	@Override
	public final ReadOnlyBooleanProperty undoAvailableProperty() {
		return undoAvailable.getReadOnlyProperty();
	}

	protected final void setUndoAvailable(boolean undoAvailable) {
		this.undoAvailable.set(undoAvailable);
	}

	@Override
	public final ReadOnlyBooleanProperty redoAvailableProperty() {
		return redoAvailable.getReadOnlyProperty();
	}

	protected final void setRedoAvailable(boolean redoAvailable) {
		this.redoAvailable.set(redoAvailable);
	}

	@Override
	public List<C> getChanges() {
		return manager.getChanges();
	}
}