package com.evanhoffman.fileorganizer;

import java.io.File;
import java.util.LinkedList;
import java.util.List;
import java.util.logging.Logger;

/**
 * Moves a bunch of files from their current locations to an arbitrary
 * target directory.
 * @author <a href="mailto:evanhoffman@evanhoffman.com">Evan Hoffman</a>
 * @since 2007-03-28
 */
public abstract class FileOrganizer {
	
	protected static Logger logger = Logger.getLogger("something");
	
	private File sourceDir = null;
	private boolean recurseSubdirs = true;
	private List<File> workFiles = null;
	
	public FileOrganizer(File sourceDir, boolean recurse) {
		this.sourceDir = sourceDir;
		this.recurseSubdirs = recurse;
	}
	
	/**
	 * Does stuff.
	 *
	 */
	public void run() {
		workFiles = getFileList(sourceDir);
		moveFiles(workFiles);
	}
	
	/**
	 * Builds a list of files that match the criteria specified in {@link #accept(File)},
	 * recursing into subdirectories {@link #recurseSubdirs} is set to true.
	 * @param dir The starting directory.
	 * @return 
	 */
	protected List<File> getFileList(File dir) {
		List<File> list = new LinkedList<File>();
		
		File dirList[] = dir.listFiles(); 
		for (File f : dirList) {
			if (f.isDirectory()) {
				if (recurseSubdirs) {
					logger.info("Recursing into subdirectory "+f);
					list.addAll(getFileList(f));
				}
			} else {
				if (accept(f)) {
					list.add(f);
					logger.info("Added file "+f);
				}
			}
		}
		
		return list;
	}
	
	/**
	 * Moves the files from their current location to the target locations
	 * returned by {@link #getTargetDirForFile(File)}.
	 * @param files
	 */
	protected void moveFiles(Iterable<File> files) {
		for (File f : files) {
			File targetDir = getTargetDirForFile(f);
			if (targetDir != null) {
				if (targetDir.exists()) {
					if (!targetDir.isDirectory()){
						throw new RuntimeException("'"+f+"' exists but is not a directory");
					}
				} else {
					if (!targetDir.mkdirs()) {
						throw new RuntimeException("Unable to create directory: "+f);
					}
				}
				
				File targetFile = new File(targetDir,f.getName());
				if (targetFile.exists()) {
					logger.info("Attempting to move "+f+" to "+targetFile+", but target already exists!");
				} else {
					if (!f.renameTo(targetFile)) {
						throw new RuntimeException("Unable to move "+f+" to "+targetFile);
					}
				}
			} else {
				logger.info("Null directory returned for file "+f);
			}
		}
	}
	
	/**
	 * Returns the directory to which the specified file should be moved, or null
	 * if the file should not be moved.
	 * @param f The file to be evaluated.
	 * @return
	 */
	protected abstract File getTargetDirForFile(File f);
	
	/**
	 * Returns true if the specified file is a candidate to be moved,
	 * false if it should be ignored.
	 * @param f The file to be evaluated.
	 * @return
	 */
	protected abstract boolean accept(File f);
	
}