/* 
 * This file is part of the Echo Web Application Framework (hereinafter "Echo").
 * Copyright (C) 2002 NextApp, Inc.
 *
 * Echo is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Echo is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Echo; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

import java.util.Iterator;

import nextapp.echo.Button;
import nextapp.echo.Color;
import nextapp.echo.ContainerPane;
import nextapp.echo.ContentPane;
import nextapp.echo.EchoInstance;
import nextapp.echo.EchoConstants;
import nextapp.echo.Filler;
import nextapp.echo.Font;
import nextapp.echo.Grid;
import nextapp.echo.Insets;
import nextapp.echo.Label;
import nextapp.echo.Panel;
import nextapp.echo.Window;

import nextapp.echo.event.ActionListener;
import nextapp.echo.event.ActionEvent;

import nextapp.echoservlet.EchoServer;

public class LayoutServlet extends EchoServer {

    public EchoInstance newInstance() {
        return new LayoutDemo();
    }
}

class LayoutDemo extends EchoInstance 
implements ActionListener {

    // Constants for fonts and colors.
    public static final Color TITLE_PANE_GRAY 
            = new Color(0x4f, 0x4f, 0x4f);
    public static final Color BUTTON_PANE_BLUE 
            = new Color(0x6f, 0x6f, 0x7f);
    public static final Font TITLE_FONT 
            = new Font(Font.VERDANA, Font.ITALIC, 18);
    
    // Constants for action commands.
    private static final String ACTION_CHANGE_BORDER_COLOR
            = "changeBorderColor";
    private static final String ACTION_CHANGE_CELL_MARGIN 
            = "changeCellMargin";
    private static final String ACTION_RANDOMIZE_CELL_COLORS
            = "randomizeCellColors";
    private static final String ACTION_CHANGE_BORDER_SIZE 
            = "changeBorderSize";
    
    // The demoGrid is protected because this class will be
    // extended in a later example and the extending class
    // will need access to it.
    protected Grid demoGrid;
    
    // In this example, Action Commands are used to 
    // determine which button was pressed when events
    // occur.  Each button has its actionCommand property
    // set to a unique string.
    public void actionPerformed(ActionEvent e) {
        if (ACTION_CHANGE_BORDER_COLOR.equals(
                e.getActionCommand())) {
            changeBorderColor();
        } else if (ACTION_CHANGE_CELL_MARGIN.equals(
                e.getActionCommand())) {
            changeCellMargin();
        } else if (ACTION_CHANGE_BORDER_SIZE.equals(
                e.getActionCommand())) {
            changeBorderSize();
        } else if (ACTION_RANDOMIZE_CELL_COLORS.equals(
                e.getActionCommand())) {
            randomizeCellColors();
        }
    }
    
    // Changes the border color of the demoGrid to a random
    // dark color.
    public void changeBorderColor() {
        demoGrid.setBorderColor(randomColor(false));
    }
    
    // Changes the border size of the demoGrid between
    // 0, 1, 2, 4, and 8 pixels.
    public void changeBorderSize() {
        if (demoGrid.getBorderSize() == 0) {
            demoGrid.setBorderSize(1);
        } else if (demoGrid.getBorderSize() < 8) {
            demoGrid.setBorderSize(
                    demoGrid.getBorderSize() * 2);
        } else {
            demoGrid.setBorderSize(0);
        }
    }
    
    // Changes the grid cell margin of the demoGrid between
    // 0, 2, 6, 14, and 30 pixels.
    public void changeCellMargin() {
        if (demoGrid.getCellMargin() < 15) {
            demoGrid.setCellMargin(
                    demoGrid.getCellMargin() * 2 + 2);
        } else {
            demoGrid.setCellMargin(0);
        }
    }
    
    // This method creates the demonstration grid that is
    // found in the main pane.
    public Grid createDemoGrid() {

        Grid grid = new Grid();
        Grid.Cell cell;
        
        // The cell margin is the whitespace that will 
        // surround the contents of every cell.
        grid.setCellMargin(4);
        
        // The grid's border color is set to a random value.
        grid.setBorderColor(randomColor(false));

        grid.setBorderSize(1);
        
        // Create a new cell.
        cell = new Grid.Cell();
        
        // Add a label to the cell.
        cell.add(new Label("A normal cell"));
        
        // Add the cell to the grid at
        // column 0, row 0.
        grid.add(0, 0, cell);
        
        // Create a new cell.
        cell = new Grid.Cell();

        // Add a label to the cell.
        cell.add(new Label("A cell that spans two columns"));

        // The cell will span two columns.
        cell.setColumnSpan(2);

        // Add the cell to the grid at
        // column 1, row 0.
        grid.add(1, 0, cell);
        
        // And so on....
        cell = new Grid.Cell();
        cell.add(new Label("Another cell"));
        grid.add(3, 0, cell);
        
        cell = new Grid.Cell();
        cell.add(new Label("Just another cell"));
        grid.add(4, 0, cell);
        
        cell = new Grid.Cell();
        cell.add(new Label("A cell that spans two rows"));
        cell.setRowSpan(2);
        grid.add(0, 1, cell);
        
        cell = new Grid.Cell();
        cell.add(new Label("Another cell"));
        grid.add(1, 1, cell);
        
        cell = new Grid.Cell();
        cell.add(new Label("Yet another cell"));
        grid.add(2, 1, cell);
        
        // There is no cell at (3,1).
        // At this location, there will be an empty hole.
        
        cell = new Grid.Cell();
        cell.add(new Label("A cell that spans four rows"));
        cell.setRowSpan(4);
        grid.add(4, 1, cell);

        cell = new Grid.Cell();
        cell.add(new Label("Another cell"));
        grid.add(1, 2, cell);
        
        cell = new Grid.Cell();
        cell.setColumnSpan(2);
        cell.setRowSpan(2);
        cell.add(new Label("A cell that spans two columns "
                + " and two rows"));
        grid.add(2, 2, cell);
        
        cell = new Grid.Cell();
        cell.add(new Label(
                "A cell that flows down into empty cells"));

        // Setting the flow of a cell will cause it to 
        // attempt to fill any empty spaces in the specified
        // direction(s).
        cell.setFlow(Grid.Cell.FLOW_DOWN);

        grid.add(0, 3, cell);
        
        cell = new Grid.Cell();
        cell.add(new Label("Another normal cell"));
        grid.add(1, 3, cell);
        
        cell = new Grid.Cell();
        cell.add(new Label("A cell that flows to the "
                 + "right into empty cells"));
        cell.setFlow(Grid.Cell.FLOW_RIGHT);
        grid.add(1, 4, cell);
        
        cell = new Grid.Cell();
        cell.add(new Label("Yet another normal cell"));
        grid.add(3, 4, cell);
        
        return grid;
    }

    // The EchoInstance's initialization method.
    // This method will setup the contents of the window.
    public Window init() {
    
        // Create a panel that will house the title text.
        Panel titlePanel = new Panel();
        
        // Set the alignment of the title panel to center
        // the title.
        titlePanel.setHorizontalAlignment(
                EchoConstants.CENTER);
                
        // Add the title text to the title pane.
        titlePanel.add(new Label("Layout Demonstration"));
        
        // Create the title title pane.
        ContentPane titlePane = new ContentPane();
        
        // The titlePane will be 40 pixels high.
        titlePane.setHeight(40);
        
        // The setScrollBarPolicy() method allows you to 
        // control whether the pane will have scroll bars.
        // In this case, we do not ever want the title
        // pane to have scroll bars, even if they would be
        // required to see all its content.
        titlePane.setScrollBarPolicy(
                ContentPane.SCROLL_BAR_NEVER);
                
        titlePane.setForeground(Color.WHITE);
        titlePane.setBackground(TITLE_PANE_GRAY);
        titlePane.setFont(TITLE_FONT);
        
        // Add the title panel to the title pane.
        titlePane.add(titlePanel);
        
        // Create a new, empty grid to hold the buttons.
        Grid buttonGrid = new Grid();
        
        // Set the cell margin to 5.
        buttonGrid.setCellMargin(5);
        
        Button button;
        button = new Button("Change Border Size");
        
        // In this example, Action Commands are used to 
        // determine which button was pressed when events
        // occur.  Each button has its actionCommand property
        // set to a unique string.  When an ActionEvent 
        // occurs, the actionPerformed() method will call 
        // the ActionEvent's getActionCommand() method to 
        // determine which button was pressed.
        button.setActionCommand(ACTION_CHANGE_BORDER_SIZE);
        
        button.addActionListener(this);
        
        // Add the button to the grid at column 0 and row 0.
        buttonGrid.add(0, 0, button);
        
        button = new Button("Change Border Color");
        button.setActionCommand(ACTION_CHANGE_BORDER_COLOR);
        button.addActionListener(this);
        buttonGrid.add(0, 1, button);
        button = new Button("Change Cell Margin");
        button.setActionCommand(ACTION_CHANGE_CELL_MARGIN);
        button.addActionListener(this);
        buttonGrid.add(0, 2, button);
        button = new Button("Randomize Cell Colors");
        button.setActionCommand(ACTION_RANDOMIZE_CELL_COLORS);
        button.addActionListener(this);
        buttonGrid.add(0, 3, button);
        
        ContentPane buttonPane = new ContentPane();
        // The buttonPane will be exactly 100 pixels wide.
        buttonPane.setWidth(100);
        
        // The buttonPane will have no scroll bars.
        buttonPane.setScrollBarPolicy(
                ContentPane.SCROLL_BAR_NEVER);
                
        // Set the insets (margins) for the button pane.
        // In this case we want all margins except the top
        // margin to be zero.  The top margin will be set
        // to thirty pixels in height.
        buttonPane.setInsets(new Insets(0, 30, 0, 0));
        
        buttonPane.setForeground(Color.WHITE);
        buttonPane.setBackground(BUTTON_PANE_BLUE);
        buttonPane.add(buttonGrid);

        // Create the main pane.
        ContentPane mainPane = new ContentPane();
        
        // Create the "demo grid" and add it to the 
        // main pane.
        demoGrid = createDemoGrid();
        mainPane.add(demoGrid);
        
        // Add thirty pixels high strut to seperate the demo
        // grid from the text that will go underneath it.
        mainPane.add(Filler.createVerticalStrut(30));
        
        // Add the upper text.
        mainPane.add(new Label("This text is positioned " 
                + "30 pixels below the grid."));
                
        // Add a zero pixel high strut to seperate the two 
        // lines of text.  A zero pixel high strut is 
        // effectively like adding a newline character.
        mainPane.add(Filler.createVerticalStrut(0));
        
        // Add the lower text.
        mainPane.add(
                new Label("This text is positioned 0 pixels "
                + "below the bottom of the text above."));
        
        
        // Craete the inner container pane.  This
        // containerPane will hold the button pane and
        // the main pane.
        ContainerPane horizontalContainer 
                = new ContainerPane();
                
        // Set this container pane to lay out its child
        // panes horizontally.
        horizontalContainer.setOrientation(
                ContainerPane.ORIENTATION_HORIZONTAL);
                
        // Add the button and main panes to the 
        // horizontal container pane.
        horizontalContainer.add(buttonPane);
        horizontalContainer.add(mainPane);
        
        
        // Create the outside container pane.  This 
        // containerPane will have the title pane on the
        // top and another pane below it.
        ContainerPane verticalContainer 
                = new ContainerPane();
        
        // Set this container pane to lay out its child
        // panes vertically.
        verticalContainer.setOrientation(
                ContainerPane.ORIENTATION_VERTICAL);

        // Add the title pane and then the horizontal
        // container pane to the vertical container
        // pane.
        verticalContainer.add(titlePane);
        verticalContainer.add(horizontalContainer);

        // Create the window
        Window window = new Window("Layout Demonstration");
        
        // Set the content of the window to be the vertical
        // (outer) container pane.
        window.setContent(verticalContainer);
        
        return window;
    }
    
    // The randomColor method returns a random Color object.
    // The boolean parameter "light" is used to 
    // determine whether the color will be very light
    // or very dark.  (In the example, dark borders
    // and light cell backgrounds are used.
    public Color randomColor(boolean light) {
        int red = ((int) Math.floor(Math.random() * 128)) 
                + (light ? 128 : 0);
        int green = ((int) Math.floor(Math.random() * 128)) 
                + (light ? 128 : 0);
        int blue = ((int) Math.floor(Math.random() * 128)) 
                + (light ? 128 : 0);
        return new Color(red, green, blue);
    }
    
    // The randomizeCellColors() method is called whenever
    // the user clicks the corresponding button in the left
    // pane.  This method will cause the background colors
    // of all cells in the grid to be set to new values.
    public void randomizeCellColors() {
        // The iterator() method will return an iterator
        // over all the cells in the grid.
        Iterator it = demoGrid.iterator();
        while (it.hasNext()) {
            ((Grid.Cell) it.next()).setBackground(
                    randomColor(true));
        }
    }
    
}