package ie.dcu.apps.ist;

import ie.dcu.apps.ist.recent.*;

import java.io.*;

/**
 * Manages applications recent files list.
 * 
 * @author Kevin McGuinness
 */
public class AppRecentFiles extends RecentFiles {
	public static final String APP_SETTINGS_PATH = ".ist";
	public static final String HISTORY_FILE_NAME = ".history";

	private static AppRecentFiles history;
	
	
	private AppRecentFiles(File store) {
		super(store);
	}
	
	
	public static AppRecentFiles getInstance() {
		if (history == null) {
			history = create();
		}
		return history;
	}
	
	
	private static AppRecentFiles create() {
		AppRecentFiles history = null;
		try {
			history = new AppRecentFiles(getHistoryFile());
			history.load();
		} catch (IOException e) {
			getLogger().warning("Unable to create history file: " + e);
		}
		
		return history;
	}
	
	
	@Override
	public void load() {
		try {
			super.load();
		} catch (IOException e) {
			getLogger().warning("Error loading recent documents list: " + e);
		}
	}

	@Override
	public void store() {
		try {
			super.store();
		} catch (IOException e) {
			getLogger().warning("Error storing recent documents list: " + e);
		}
	}


	private static File getHistoryFile() throws IOException {
		File file = new File(getSettingsDirectory(), HISTORY_FILE_NAME);
		if (file.exists()) {
			// Check we can write
			if (file.canWrite()) {
				return file;
			}
		} else {
			return file;
		}
		
		throw new IOException("History file is unwritable");
	}


	private static File getSettingsDirectory() throws IOException {
		String home = System.getProperty("user.home");
		File settings = new File(home, APP_SETTINGS_PATH);
		
		if (!settings.exists()) {
			if (settings.mkdirs()) {
				return settings;
			}
		} else {
			return settings;
		}
		
		throw new IOException("Unable to create application settings directory");
	}
}