package net.kenevans.dilbert.utils;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.swing.JFileChooser;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;

public class Utils
{
  public static final String LS = System.getProperty("line.separator");

  /**
   * Generic method to get a file suing a JFileChooder
   * @param defaultPath
   * @return the File or null if aborted.
   */
  public static File getOpenFile(String defaultPath) {
    File file = null;
    JFileChooser chooser = new JFileChooser();
    if(defaultPath != null) {
      chooser.setCurrentDirectory(new File(defaultPath));
    }
    int result = chooser.showOpenDialog(null);
    if(result == JFileChooser.APPROVE_OPTION) {
      // Save the selected path for next time
      defaultPath = chooser.getSelectedFile().getParentFile().getPath();
      // Process the file
      file = chooser.getSelectedFile();
    }
    return file;
  }

  /**
   * Error message dialog
   * 
   * @param msg
   */
  public static void errMsg(final String msg) {
    // Show it in a message box
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        JOptionPane.showMessageDialog(null, msg, "Error",
          JOptionPane.ERROR_MESSAGE);
        System.out.println(msg);
      }
    });
  }
  
  /**
   * Warning message dialog
   * 
   * @param msg
   */
  public static void warnMsg(final String msg) {
    // Show it in a message box
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        JOptionPane.showMessageDialog(null, msg, "Warning",
          JOptionPane.WARNING_MESSAGE);
        System.out.println(msg);
      }
    });
  }
  
  /**
   * Information message dialog
   * 
   * @param msg
   */
  public static void infoMsg(final String msg) {
    // Show it in a message box
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        JOptionPane.showMessageDialog(null, msg, "Information",
          JOptionPane.INFORMATION_MESSAGE);
        System.out.println(msg);
      }
    });
  }
  
  /**
   * Exception message dialog. Displays message plus the exception and exception
   * message.
   * 
   * @param msg
   * @param ex
   */
  public static void excMsg(String msg, Exception ex) {
    final String fullMsg = msg += LS + "Exception: " + ex + LS
      + ex.getMessage();
    // Show it in a message box
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        JOptionPane.showMessageDialog(null, fullMsg, "Error",
          JOptionPane.ERROR_MESSAGE);
        System.out.println(fullMsg);
      }
    });
  }
  
  /**
   * Exception message dialog. Displays message plus the error and error
   * message.
   * 
   * @param msg
   * @param ex
   */
  public static void excMsg(String msg, Error ex) {
    final String fullMsg = msg += LS + "Exception: " + ex + LS + ex.getMessage();
    // Show it in a message box
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        JOptionPane.showMessageDialog(null, fullMsg, "Error",
          JOptionPane.ERROR_MESSAGE);
      }
    });
  }
  
  /**
   * Get the extension of a file (without the dot).
   * @param file
   * @return
   */
  public static String getExtension(File file) {
      String ext = null;
      String s = file.getName();
      int i = s.lastIndexOf('.');
      if (i > 0 &&  i < s.length() - 1) {
          ext = s.substring(i+1).toLowerCase();
      }
      return ext;
  }

  /**
   * Returns the contents of a file as a byte array.
   * 
   * @param file
   * @return
   * @throws IOException
   */
  public byte[] loadFileBytes(File file) throws IOException {
    if(file == null) return null;
    if(!file.exists()) {
      throw new IOException("File does not exist");
    }
    int len = (int)file.length();
    if(len == 0) {
      throw new IOException("File is empty");
    }
    byte bytes[] = new byte[len]; // Has to be int here
    int nRead = 0;
    FileInputStream in = null;
    try {
      in = new FileInputStream(file);
      nRead = in.read(bytes);
      if(nRead != len) {
        throw new IOException("Only read " + nRead + " of " + len + " bytes");
      }
      return bytes;
    } finally {
      if(in != null) in.close();
    }
  }

  /**
   * Generates a timestamp.
   * 
   * @return String timestamp with the current time
   */
  public static String timeStamp() {
    Date now = new Date();
    final SimpleDateFormat defaultFormatter = new SimpleDateFormat(
      "MMM dd, yyyy HH:mm:ss.SSS");
    return defaultFormatter.format(now);
  }

  /**
   * Generates a timestamp given a pattern
   * 
   * @param pattern appropriate for SimpleDateFormat
   * @return String timestamp with the current time
   */
  public static String timeStamp(String pattern) {
    Date now = new Date();
    final SimpleDateFormat dateFormatter = new SimpleDateFormat(pattern);
    return dateFormatter.format(now);
  }
  
}