import javax.swing.JFileChooser;
import java.io.File;     
import java.util.Scanner;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;

/**
 * Searches for filename matches on your disk.
 *
 * @author Brad Richards
 * @version 1.1
 */
public class FileSearch
{
    // We could "print" to this output window instead of out
    // if we wanted to make this a standalone application.
    private static TextDisplay out = new TextDisplay();

    /**
     * Bring up a dialog box and let the user select a directory.  If
     * they cancel out without selecting a valid directory, this method
     * returns null.
     * 
     * @return A File object corresponding to the selected directory, or null.
     */
    public static File getDirectory() 
    {
        File selected = null;
        JFileChooser fileChooser = new JFileChooser();
        fileChooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
        fileChooser.setDialogTitle("Please select a directory to search");
        int result = fileChooser.showOpenDialog(null);
        if (result == JFileChooser.APPROVE_OPTION) {
            selected = fileChooser.getSelectedFile();
        }
        return selected;
    }

    /**
     * Looks through the contents of the specified directory and prints
     * information about files whose names contain the specified search term.
     * 
     * @param directory  File object representing the directory to be searched
     * @param key  A string containing text we're looking for
     */
    public static void listMatches(File directory, String key)
    {
        if (directory != null && directory.isDirectory()) {
            File[] contents = directory.listFiles();  // Get contents of directory
            // out.println("Directory contains "+contents.length+" files");
            // out.println("First file's name is "+contents[0].getName());
            for(File oneFile : contents) {
                if (oneFile.isDirectory()) {
                    out.println("Searching subdirectory: "+oneFile.getName());
                    listMatches(oneFile, key);
                }
                else {
                    if (oneFile.getName().contains(key)) {
                        out.println(oneFile.getName());
                    }
                }
            }
        }
    }

    /**
     * This pulls the pieces together:  It prompts the user for some search
     * text, calls getDirectory() so the user can select a directory to search,
     * and prints "Done" once the search finishes so the user knows it's done.
     */
    public static void runSearch() 
    {
        String key = JOptionPane.showInputDialog("Search for what?");
        // Have user select directory
        File directory = getDirectory();
        if (directory != null) {
            out.println("Searching "+directory.getAbsolutePath());
            // Pass directory and search key info to listMatches
            listMatches(directory, key);
            // Print "done".
            out.println("Done.");
        }
        else {
            out.println("Didn't select a directory.");
        }

    }

    /**
     * This is really gross, and you don't need to understand it.  The issue
     * is that our program pulls up dialog boxes like JFileChooser, and those
     * are officially supposed to be created on a separate "thread" or they
     * can deadlock.  (In English: Our program can "hang" without making any
     * progress if we don't let it run in its own personal "space".)  The code
     * below creates a separate thread and starts runSearch() running in that
     * thread.
     */
    public static void main(String[] args) 
    {
        SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    runSearch();
                }
            });
    }
}