package dev.kske.undoredo.core;

import java.util.List;

/**
 * A change manager keeps track of subsequent changes and allows un- and redoing them. A specific
 * change can be marked using {@link #mark()} to keep track of a saved state in the application that
 * uses the manager.
 *
 * @param <C> the change type to store in this change manager
 * @author Maximilian K&auml;fer
 * @author Kai S. K. Engelbart
 * @since 0.0.1
 */
public interface ChangeManager<C extends Change> {

	/**
	 * Applies the given change and appends it to the change list.
	 *
	 * @param change the change to add
	 * @since 0.0.1
	 */
	void addChange(C change);

	/**
	 * Undoes the current change.
	 *
	 * @return whether an action was performed
	 * @since 0.1.0
	 */
	boolean undo();

	/**
	 * Applies the change that was undone before.
	 *
	 * @return whether an action was performed
	 * @since 0.0.1
	 */
	boolean redo();

	/**
	 * Marks the current change.
	 *
	 * @since 0.0.1
	 */
	void mark();

	/**
	 * @return whether the current change is marked
	 * @since 0.0.1
	 */
	boolean isAtMarkedIndex();

	/**
	 * @return whether a change is present that can be undone
	 * @since 0.0.1
	 */
	boolean isUndoAvailable();

	/**
	 * @return whether a change is present that can be redone
	 * @since 0.0.1
	 */
	boolean isRedoAvailable();

	/**
	 * Provides an unmodifiable view of the changes stored in this change manager.
	 *
	 * @return all stored changes
	 * @since 0.0.1
	 */
	List<C> getChanges();
}