package javax.swing;

import java.awt.Component;
import java.awt.Graphics;
import javax.accessibility.Accessible;
import javax.accessibility.AccessibleContext;
import javax.accessibility.AccessibleRole;
import javax.accessibility.AccessibleStateSet;
import javax.accessibility.AccessibleValue;
import javax.swing.UIManager;
import javax.swing.plaf.SplitPaneUI;


/**
 * This class implements JSplitPane. It is used to divide two components. By
 * dragging the SplitPane's divider, the user can resize the two components.
 * Note that the divider cannot resize a component to smaller than it's
 * minimum size.
 */
public class JSplitPane extends JComponent implements Accessible
{
  /**
   * DOCUMENT ME!
   */
  protected class AccessibleJSplitPane extends JComponent.AccessibleJComponent
    implements AccessibleValue
  {
    /**
     * Creates a new AccessibleJSplitPane object.
     *
     * @param value0 DOCUMENT ME!
     */
    protected AccessibleJSplitPane(JSplitPane value0)
    {
      super(value0);
    }

    /**
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public AccessibleStateSet getAccessibleStateSet()
    {
      return null;
    }

    /**
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public AccessibleRole getAccessibleRole()
    {
      return null;
    }

    /**
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public AccessibleValue getAccessibleValue()
    {
      return null;
    }

    /**
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public Number getCurrentAccessibleValue()
    {
      return null;
    }

    /**
     * DOCUMENT ME!
     *
     * @param value0 DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public boolean setCurrentAccessibleValue(Number value0)
    {
      return false;
    }

    /**
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public Number getMinimumAccessibleValue()
    {
      return null;
    }

    /**
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public Number getMaximumAccessibleValue()
    {
      return null;
    }
  }

  /** The constraints string used to add components to the bottom. */
  public static final String BOTTOM = "bottom";

  /** The property fired when the continuousLayout property changes. */
  public static final String CONTINUOUS_LAYOUT_PROPERTY = "continuousLayout";

  /** The property fired when the divider property changes. */
  public static final String DIVIDER = "divider";

  /** The property fired when the divider location property changes. */
  public static final String DIVIDER_LOCATION_PROPERTY = "dividerLocation";

  /** The property fired when the divider size property changes. */
  public static final String DIVIDER_SIZE_PROPERTY = "dividerSize";

  /**
   * The value of the orientation when the components are split horizontally.
   */
  public static final int HORIZONTAL_SPLIT = 1;

  /** The property fired when the last divider location property changes. */
  public static final String LAST_DIVIDER_LOCATION_PROPERTY = "lastDividerLocation";

  /** The constraints string used to add components to the left. */
  public static final String LEFT = "left";

  /** The property fired when the one touch expandable property changes. */
  public static final String ONE_TOUCH_EXPANDABLE_PROPERTY = "oneTouchExpandable";

  /** The property fired when the orientation property changes. */
  public static final String ORIENTATION_PROPERTY = "orientation";

  /** The property fired when the resize weight property changes. */
  public static final String RESIZE_WEIGHT_PROPERTY = "resizeWeight";

  /** The constraints string used to add components to the right. */
  public static final String RIGHT = "right";

  /** The constraints string used to add components to the top. */
  public static final String TOP = "top";

  /** The value of the orientation when the components are split vertically. */
  public static final int VERTICAL_SPLIT = 0;

  /** Whether the JSplitPane uses continuous layout. */
  protected boolean continuousLayout;

  /** Whether the JSplitPane uses one touch expandable buttons. */
  protected boolean oneTouchExpandable = false;

  // This is the master dividerSize variable and sets the BasicSplitPaneDivider one accordingly

  /** The size of the divider. */
  protected int dividerSize = 10;

  /** The last location of the divider given by the UI. */
  protected int lastDividerLocation;

  /** The orientation of the JSplitPane. */
  protected int orientation;

  /** The component on the top or left. */
  protected Component leftComponent;

  /** The component on the right or bottom. */
  protected Component rightComponent;

  /** Determines how extra space should be allocated. */
  private transient double resizeWeight;

  /**
   * Creates a new JSplitPane object with the given orientation, layout mode,
   * and left and right components.
   *
   * @param newOrientation The orientation to use.
   * @param newContinuousLayout The layout mode to use.
   * @param newLeftComponent The left component.
   * @param newRightComponent The right component.
   *
   * @throws IllegalArgumentException DOCUMENT ME!
   */
  public JSplitPane(int newOrientation, boolean newContinuousLayout,
                    Component newLeftComponent, Component newRightComponent)
  {
    if (newOrientation != HORIZONTAL_SPLIT && newOrientation != VERTICAL_SPLIT)
      throw new IllegalArgumentException("orientation is invalid.");
    orientation = newOrientation;
    continuousLayout = newContinuousLayout;
    setLeftComponent(newLeftComponent);
    setRightComponent(newRightComponent);

    updateUI();
  }

  /**
   * Creates a new JSplitPane object using nonContinuousLayout mode, the given
   * orientation and left and right components.
   *
   * @param newOrientation The orientation to use.
   * @param newLeftComponent The left component.
   * @param newRightComponent The right component.
   */
  public JSplitPane(int newOrientation, Component newLeftComponent,
                    Component newRightComponent)
  {
    this(newOrientation, false, newLeftComponent, newRightComponent);
  }

  /**
   * Creates a new JSplitPane object with the given layout mode and
   * orientation.
   *
   * @param newOrientation The orientation to use.
   * @param newContinuousLayout The layout mode to use.
   */
  public JSplitPane(int newOrientation, boolean newContinuousLayout)
  {
    this(newOrientation, newContinuousLayout, null, null);
  }

  /**
   * Creates a new JSplitPane object using a nonContinuousLayout mode and the
   * given orientation.
   *
   * @param newOrientation The orientation to use.
   */
  public JSplitPane(int newOrientation)
  {
    this(newOrientation, false, null, null);
  }

  /**
   * Creates a new JSplitPane object using HORIZONTAL_SPLIT and a
   * nonContinuousLayout mode.
   */
  public JSplitPane()
  {
    this(HORIZONTAL_SPLIT, false, null, null);
  }

  /**
   * This method adds a component to the JSplitPane. The constraints object is
   * a string that identifies where this component should go. If the
   * constraints is not a known one, it will throw an
   * IllegalArgumentException. The valid constraints are LEFT, TOP, RIGHT,
   * BOTTOM and DIVIDER.
   *
   * @param comp The component to add.
   * @param constraints The constraints string to use.
   * @param index Where to place to component in the list of components.
   *
   * @throws IllegalArgumentException When the constraints is not a known identifier.
   */
  protected void addImpl(Component comp, Object constraints, int index)
  {
    int left = 0;
    int right = 1;
    int div = 2;
    int place;
    if (constraints == null)
      {
	if (leftComponent == null)
	  constraints = LEFT;
	else if (rightComponent == null)
	  constraints = RIGHT;
      }

    if (constraints instanceof String)
      {
	String placement = (String) constraints;

	if (placement.equals(BOTTOM) || placement.equals(RIGHT))
	  {
	    if (rightComponent != null)
		remove(rightComponent);
	    rightComponent = comp;
	  }
	else if (placement.equals(LEFT) || placement.equals(TOP))
	  {
	    if (leftComponent != null)
	      remove(leftComponent);
	    leftComponent = comp;
	  }
	else if (placement.equals(DIVIDER))
	  constraints = null;
	else
	  throw new IllegalArgumentException("Constraints is not a known identifier.");

	super.addImpl(comp, constraints, index);
      }
    invalidate();
    layout();
  }

  /**
   * DOCUMENT ME!
   *
   * @return DOCUMENT ME!
   */
  public AccessibleContext getAccessibleContext()
  {
    if (accessibleContext == null)
      accessibleContext = new AccessibleJSplitPane(this);
    return accessibleContext;
  }

  /**
   * This method returns the bottom component.
   *
   * @return The bottom component.
   */
  public Component getBottomComponent()
  {
    return rightComponent;
  }

  /**
   * This method returns the location of the divider. This method is passed to
   * the UI.
   *
   * @return The location of the divider.
   */
  public int getDividerLocation()
  {
    if (ui != null)
      return ((SplitPaneUI) ui).getDividerLocation(this);
    else
      return -1;
  }

  /**
   * This method returns the size of the divider.
   *
   * @return The size of the divider.
   */
  public int getDividerSize()
  {
    return dividerSize;
  }

  /**
   * This method returns the last divider location.
   *
   * @return The last divider location.
   */
  public int getLastDividerLocation()
  {
    return lastDividerLocation;
  }

  /**
   * This method returns the left component.
   *
   * @return The left component.
   */
  public Component getLeftComponent()
  {
    return leftComponent;
  }

  /**
   * This method returns the maximum divider location. This method is passed
   * to  the UI.
   *
   * @return DOCUMENT ME!
   */
  public int getMaximumDividerLocation()
  {
    if (ui != null)
      return ((SplitPaneUI) ui).getMaximumDividerLocation(this);
    else
      return -1;
  }

  /**
   * This method returns the minimum divider location. This method is passed
   * to the UI.
   *
   * @return The minimum divider location.
   */
  public int getMinimumDividerLocation()
  {
    if (ui != null)
      return ((SplitPaneUI) ui).getMinimumDividerLocation(this);
    else
      return -1;
  }

  /**
   * This method returns the orientation that the JSplitPane is using.
   *
   * @return The current orientation.
   */
  public int getOrientation()
  {
    return orientation;
  }

  /**
   * This method returns the current resize weight.
   *
   * @return The current resize weight.
   */
  public double getResizeWeight()
  {
    return resizeWeight;
  }

  /**
   * This method returns the right component.
   *
   * @return The right component.
   */
  public Component getRightComponent()
  {
    return rightComponent;
  }

  /**
   * This method returns the top component.
   *
   * @return The top component.
   */
  public Component getTopComponent()
  {
    return leftComponent;
  }

  /**
   * This method returns the UI.
   *
   * @return The UI.
   */
  public SplitPaneUI getUI()
  {
    return (SplitPaneUI) ui;
  }

  /**
   * This method returns true if the JSplitPane is using a continuousLayout.
   *
   * @return True if using a continuousLayout.
   */
  public boolean isContinuousLayout()
  {
    return continuousLayout;
  }

  /**
   * This method returns true if the divider has one touch expandable buttons.
   *
   * @return True if one touch expandable is used.
   */
  public boolean isOneTouchExpandable()
  {
    return oneTouchExpandable;
  }

  /**
   * This method returns true.
   *
   * @return true.
   */
  public boolean isValidateRoot()
  {
    return true;
  }

  /**
   * This method overrides JComponent's paintChildren so the UI can be
   * messaged when the children have finished painting.
   *
   * @param g The Graphics object to paint with.
   */
  protected void paintChildren(Graphics g)
  {
    super.paintChildren(g);
    if (ui != null)
      ((SplitPaneUI) ui).finishedPaintingChildren(this, g);
  }

  /**
   * This method returns a String that describes this JSplitPane. The string
   * is primarily used for debugging purposes.
   *
   * @return A String used for debugging purposes.
   */
  protected String paramString()
  {
    return "JSplitPane";
  }

  /**
   * This method removes the given component from the JSplitPane.
   *
   * @param component The Component to remove.
   */
  public void remove(Component component)
  {
    if (component == leftComponent)
      leftComponent = null;
    else if (component == rightComponent)
      rightComponent = null;
    super.remove(component);
  }

  /**
   * This method removes the component at the given index.
   *
   * @param index The index of the component to remove.
   */
  public void remove(int index)
  {
    Component component = getComponentAt(index);
    if (component == leftComponent)
      leftComponent = null;
    else if (component == rightComponent)
      rightComponent = null;
    super.remove(index);
  }

  /**
   * This method removes all components from the JSplitPane.
   */
  public void removeAll()
  {
    leftComponent = null;
    rightComponent = null;
    super.removeAll();
  }

  /**
   * This method resets all children of the JSplitPane to their preferred
   * sizes.
   */
  public void resetToPreferredSizes()
  {
    if (ui != null)
      ((SplitPaneUI) ui).resetToPreferredSizes(this);
  }

  /**
   * This method sets the bottom component.
   *
   * @param comp The Component to be placed at the bottom.
   */
  public void setBottomComponent(Component comp)
  {
    if (comp != null)
      add(comp, BOTTOM);
    else
      add(new JButton("right button"), BOTTOM);
  }

  /**
   * This method sets the layout mode for the JSplitPane.
   *
   * @param newContinuousLayout Whether the JSplitPane is in continuousLayout
   *        mode.
   */
  public void setContinuousLayout(boolean newContinuousLayout)
  {
    if (newContinuousLayout != continuousLayout)
      {
	boolean oldValue = continuousLayout;
	continuousLayout = newContinuousLayout;
	firePropertyChange(CONTINUOUS_LAYOUT_PROPERTY, oldValue,
	                   continuousLayout);
      }
  }

  /**
   * This method sets the location of the divider. A value of 0 sets the
   * divider to the farthest left. A value of 1 sets the divider to the
   * farthest right.
   *
   * @param proportionalLocation A double that describes the location of the
   *        divider.
   *
   * @throws IllegalArgumentException DOCUMENT ME!
   */
  public void setDividerLocation(double proportionalLocation)
  {
    if (proportionalLocation > 1 || proportionalLocation < 0)
      throw new IllegalArgumentException("proportion has to be between 0 and 1.");

    int max = (orientation == HORIZONTAL_SPLIT) ? getWidth() : getHeight();
    setDividerLocation((int) (proportionalLocation * max));
  }

  /**
   * This method sets the location of the divider.
   *
   * @param location The location of the divider.
   */
  public void setDividerLocation(int location)
  {
    if (ui != null && location != getDividerLocation())
      {
	int oldLocation = getDividerLocation();
	((SplitPaneUI) ui).setDividerLocation(this, location);
	firePropertyChange(DIVIDER_LOCATION_PROPERTY, oldLocation, location);
      }
  }

  /**
   * This method sets the size of the divider.
   *
   * @param newSize The size of the divider.
   */
  public void setDividerSize(int newSize)
  {
    if (newSize != dividerSize)
      {
	int oldSize = dividerSize;
	dividerSize = newSize;
	firePropertyChange(DIVIDER_SIZE_PROPERTY, oldSize, dividerSize);
      }
  }

  // This doesn't appear to do anything when set from user side.
  // so it probably is only used from the UI side to change the
  // lastDividerLocation var.

  /**
   * This method sets the last location of the divider.
   *
   * @param newLastLocation The last location of the divider.
   */
  public void setLastDividerLocation(int newLastLocation)
  {
    if (newLastLocation != lastDividerLocation)
      {
	int oldValue = lastDividerLocation;
	lastDividerLocation = newLastLocation;
	firePropertyChange(LAST_DIVIDER_LOCATION_PROPERTY, oldValue,
	                   lastDividerLocation);
      }
  }

  /**
   * This method sets the left component.
   *
   * @param comp The left component.
   */
  public void setLeftComponent(Component comp)
  {
    if (comp != null)
      add(comp, LEFT);
    else
      add(new JButton("left button"), LEFT);
  }

  /**
   * This method sets whether the divider has one touch expandable buttons.
   * The one touch expandable buttons can expand the size of either component
   * to the maximum allowed size.
   *
   * @param newValue Whether the divider will have one touch expandable
   *        buttons.
   */
  public void setOneTouchExpandable(boolean newValue)
  {
    if (newValue != oneTouchExpandable)
      {
	boolean oldValue = oneTouchExpandable;
	oneTouchExpandable = newValue;
	firePropertyChange(ONE_TOUCH_EXPANDABLE_PROPERTY, oldValue,
	                   oneTouchExpandable);
      }
  }

  /**
   * This method sets the orientation of the JSplitPane.
   *
   * @param orientation The orientation of the JSplitPane.
   *
   * @throws IllegalArgumentException DOCUMENT ME!
   */
  public void setOrientation(int orientation)
  {
    if (orientation != HORIZONTAL_SPLIT && orientation != VERTICAL_SPLIT)
      throw new IllegalArgumentException("orientation must be one of VERTICAL_SPLIT, HORIZONTAL_SPLIT");
    if (orientation != this.orientation)
      {
	int oldOrientation = this.orientation;
	this.orientation = orientation;
	firePropertyChange(ORIENTATION_PROPERTY, oldOrientation,
	                   this.orientation);
      }
  }

  /**
   * This method determines how extra space will be distributed among the left
   * and right components. A value of 0 will allocate all extra space to the
   * right component. A value of 1 indicates that all extra space will go to
   * the left component. A value in between 1 and 0 will split the space
   * accordingly.
   *
   * @param value The resize weight.
   */
  public void setResizeWeight(double value)
  {
    resizeWeight = value;
  }

  /**
   * This method sets the right component.
   *
   * @param comp The right component.
   */
  public void setRightComponent(Component comp)
  {
    if (comp != null)
      add(comp, RIGHT);
    else
	add(new JButton("right button"), RIGHT);
  }

  /**
   * This method sets the top component.
   *
   * @param comp The top component.
   */
  public void setTopComponent(Component comp)
  {
    if (comp != null)
      add(comp, TOP);
    else
      add(new JButton("left button"), TOP);
  }

  /**
   * This method sets the UI used by the JSplitPane.
   *
   * @param ui The UI to use.
   */
  public void setUI(SplitPaneUI ui)
  {
    super.setUI(ui);
  }

  /**
   * This method resets the UI to the one specified by the current Look and
   * Feel.
   */
  public void updateUI()
  {
    setUI((SplitPaneUI) UIManager.getUI(this));
    invalidate();
    repaint();
  }

  /**
   * This method returns a string identifier to determine which UI class it
   * needs.
   *
   * @return A string that identifies it's UI class.
   */
  public String getUIClassID()
  {
    return "SplitPaneUI";
  }
}