import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.border.BevelBorder;
import javax.swing.border.SoftBevelBorder;
import javax.swing.border.TitledBorder;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;


public class GUI {
   private JButton imageSizeBtnCancel;
   private JFrame frameimgSize;
   private JFormattedTextField widthArea;
   private JFormattedTextField heightArea;
   private JComboBox comboBoxWidth;
   private JCheckBox checkBoxImage;
   private JComboBox comboBoxHeight;
   private double aspectRatio = 16/9;
   public GUI(){

          frameimgSize = new JFrame("Image Size");
          frameimgSize.setLocationRelativeTo(null);
          frameimgSize.setAlwaysOnTop(true);
          frameimgSize.setSize(400, 200);
          frameimgSize.setDefaultCloseOperation(frameimgSize.DISPOSE_ON_CLOSE);
          frameimgSize.setResizable(false);
          frameimgSize.getContentPane().setLayout(null);
          frameimgSize.setVisible(true);

          JPanel panel = new JPanel();
          panel.setBorder(new TitledBorder(UIManager.getBorder("TitledBorder.border"), "Image resize", TitledBorder.LEADING, TitledBorder.TOP, null, null));
          panel.setBounds(0, 11, 283, 150);
          frameimgSize.getContentPane().add(panel);
          panel.setLayout(null);
          JLabel widthLabel = new JLabel("Width:");
          widthLabel.setBounds(17, 40, 38, 20);
          panel.add(widthLabel);

          JLabel heightLabel = new JLabel("Height:");
          heightLabel.setBounds(17, 77, 39, 20);
          panel.add(heightLabel);

          JPanel panel_1 = new JPanel();
          panel_1.setBorder(new SoftBevelBorder(BevelBorder.LOWERED, null, null, null, null));
          panel_1.setBounds(62, 40, 90, 20);
          panel.add(panel_1);
          panel_1.setLayout(null);

          widthArea = new JFormattedTextField("");
          widthArea.setBounds(3, 4, 85, 16);
          panel_1.add(widthArea);

          JPanel panel_2 = new JPanel();
          panel_2.setBorder(new SoftBevelBorder(BevelBorder.LOWERED, null, null, null, null));
          panel_2.setBounds(62, 74, 90, 20);
          panel.add(panel_2);
          panel_2.setLayout(null);

          heightArea = new JFormattedTextField("");
          heightArea.setBounds(3, 4, 85, 16);
          panel_2.add(heightArea);

          checkBoxImage = new JCheckBox("Constrain Proportions");
          checkBoxImage.setBounds(12, 109, 235, 23);
          checkBoxImage.setSelected(true);
          panel.add(checkBoxImage);

          comboBoxWidth = new JComboBox();
          comboBoxWidth.addItem("Pixels");
          comboBoxWidth.addItem("Percent");
          comboBoxWidth.setBounds(181, 40, 72, 20);
          panel.add(comboBoxWidth);

          comboBoxHeight = new JComboBox();
          comboBoxHeight.addItem("Pixels");
          comboBoxHeight.addItem("Percent");

          comboBoxHeight.setBounds(181, 77, 72, 20);
          panel.add(comboBoxHeight);

          JButton imageSizebtnOK = new JButton("OK");
          imageSizebtnOK.setBounds(295, 21, 89, 23);
          imageSizebtnOK.addActionListener(new sizeImageOK() );
          frameimgSize.getContentPane().add(imageSizebtnOK);

          JButton imageSizeBtnCancel = new JButton("Cancel");
          imageSizeBtnCancel.setBounds(295, 61, 89, 23);
          imageSizeBtnCancel.addActionListener(new sizeImageCancel());

          frameimgSize.getContentPane().add(imageSizeBtnCancel);
          // retrieving AR for current selected image

          heightArea.getDocument().addDocumentListener(new sizeImageWidthUpdate() );
          widthArea.getDocument().addDocumentListener(new sizeImageHeightUpdate() );
   }

   //--------METHODS
   private void updateHeight(){

          if(widthArea.getText().length() != 0 && widthArea.getText().length() <= 5 &&
                  widthArea.getText().charAt(0) != '0' && checkBoxImage.isSelected()){
              String width = widthArea.getText();
              try{
                  int widthNum = Integer.parseInt(width);
                  int heightNum = (int) Math.round(aspectRatio * widthNum);
                  heightArea.setText(String.valueOf(heightNum) );
                  System.out.println("Height should be updated");
              }
              catch(NumberFormatException e1){JOptionPane.showMessageDialog(new JOptionPane(),e1.getMessage(),"Error", JOptionPane.ERROR_MESSAGE);}
          }
      }
      // image resizing, width updating method for keeping AR
      private void updateWidth(){

          if (checkBoxImage.isSelected()){
              String height = heightArea.getText();
              /**
               * to do, update width, height area
               * to the closest user input
               */
              if(heightArea.getText().length() != 0 && heightArea.getText().length() <= 4
                      && heightArea.getText().charAt(0) != '0'){
                  //parsing string to integer
                  try{
                      int heightNum = Integer.parseInt(height);
                      int widthNum = (int) Math.round(aspectRatio * heightNum);   // calculating required width to keep AR
                      widthArea.setText(String.valueOf(widthNum) );
                      System.out.println("width should be updated.");
                  }
                  catch(NumberFormatException e1){JOptionPane.showMessageDialog(new JOptionPane(),e1.getMessage(),"Error", JOptionPane.ERROR_MESSAGE);}
              }
          }
      }
   //-------LISTENERS----------

   public class sizeImageCancel implements ActionListener{
          public void actionPerformed(ActionEvent e){
              frameimgSize.dispose();
          }
      }
      public class sizeImageOK implements ActionListener{
          public void actionPerformed(ActionEvent e){
              /**
               * To DO : retrieve width and height and check whether it is valid.
               * Check whether image is present for sizing.
               * Resize image, dispose frame.
               */

          }
      }

      //if focus on width add this listeners
      public class sizeImageHeightUpdate implements DocumentListener{
          public void changedUpdate(DocumentEvent e){}
          public void insertUpdate(DocumentEvent e){updateHeight();}
          public void removeUpdate(DocumentEvent e){}
      }
      //else if focus on height add this
      public class sizeImageWidthUpdate implements DocumentListener{
          public void changedUpdate(DocumentEvent e){}
          public void insertUpdate(DocumentEvent e){updateWidth(); }
          public void removeUpdate(DocumentEvent e){}
      }
}