/*******************************************************************************
 * Copyright (c) 2000, 2007 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
module dwt.widgets.Scrollable;

import dwt.dwthelper.utils;


import dwt.DWT;
import dwt.DWTException;
import dwt.graphics.Rectangle;
import dwt.internal.cocoa.NSRect;
import dwt.internal.cocoa.NSScrollView;
import dwt.internal.cocoa.NSScroller;
import dwt.internal.cocoa.NSSize;
import dwt.internal.cocoa.NSView;
import dwt.internal.cocoa.OS;
import dwt.internal.cocoa.SWTScrollView;

/**
 * This class is the abstract superclass of all classes which
 * represent controls that have standard scroll bars.
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>H_SCROLL, V_SCROLL</dd>
 * <dt><b>Events:</b>
 * <dd>(none)</dd>
 * </dl>
 * <p>
 * IMPORTANT: This class is intended to be subclassed <em>only</em>
 * within the DWT implementation.
 * </p>
 */
public abstract class Scrollable extends Control {
    SWTScrollView scrollView;
    ScrollBar horizontalBar, verticalBar;
    
Scrollable () {
    /* Do nothing */
}

/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>DWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together 
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>DWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a composite control which will be the parent of the new instance (cannot be null)
 * @param style the style of control to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 *
 * @see DWT#H_SCROLL
 * @see DWT#V_SCROLL
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public Scrollable (Composite parent, int style) {
    super (parent, style);
}

/**
 * Given a desired <em>client area</em> for the receiver
 * (as described by the arguments), returns the bounding
 * rectangle which would be required to produce that client
 * area.
 * <p>
 * In other words, it returns a rectangle such that, if the
 * receiver's bounds were set to that rectangle, the area
 * of the receiver which is capable of displaying data
 * (that is, not covered by the "trimmings") would be the
 * rectangle described by the arguments (relative to the
 * receiver's parent).
 * </p>
 * 
 * @param x the desired x coordinate of the client area
 * @param y the desired y coordinate of the client area
 * @param width the desired width of the client area
 * @param height the desired height of the client area
 * @return the required bounds to produce the given client area
 *
 * @exception DWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see #getClientArea
 */
public Rectangle computeTrim (int x, int y, int width, int height) {
    checkWidget();
    if (scrollView !is null) {
        NSSize size = new NSSize();
        size.width = width;
        size.height = height;
        int border = hasBorder() ? OS.NSBezelBorder : OS.NSNoBorder;
        size = NSScrollView.frameSizeForContentSize(size, (style & DWT.H_SCROLL) !is 0, (style & DWT.V_SCROLL) !is 0, border);
        width = (int)size.width;
        height = (int)size.height;
        NSRect frame = scrollView.contentView().frame();
        x -= frame.x;
        y -= frame.y;
    }
    return new Rectangle (x, y, width, height);
}

ScrollBar createScrollBar (int style) {
    if (scrollView is null) return null;
    ScrollBar bar = new ScrollBar ();
    bar.parent = this;
    bar.style = style;
    bar.display = display;
    NSScroller scroller;
    int actionSelector;
    if ((style & DWT.H_SCROLL) !is 0) {
        scroller = scrollView.horizontalScroller();
        actionSelector = OS.sel_sendHorizontalSelection;
    } else {
        scroller = scrollView.verticalScroller();
        actionSelector = OS.sel_sendVerticalSelection;
    }
    bar.view = scroller;
    bar.createJNIRef();
    scroller.setTag(bar.jniRef);
    if ((state & CANVAS) is 0) {
        bar.target = scroller.target();
        bar.actionSelector = scroller.action();
    }
    scroller.setTarget(scrollView);
    scroller.setAction(actionSelector);
    return bar;
}

void createWidget () {
    super.createWidget ();
    if ((style & DWT.H_SCROLL) !is 0) horizontalBar = createScrollBar (DWT.H_SCROLL);
    if ((style & DWT.V_SCROLL) !is 0) verticalBar = createScrollBar (DWT.V_SCROLL);
}

/**
 * Returns a rectangle which describes the area of the
 * receiver which is capable of displaying data (that is,
 * not covered by the "trimmings").
 * 
 * @return the client area
 *
 * @exception DWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see #computeTrim
 */
public Rectangle getClientArea () {
    checkWidget();
    if (scrollView !is null) {
        NSSize size = scrollView.contentSize();
        return new Rectangle(0, 0, (int)size.width, (int)size.height);
    } else {
        NSRect rect = view.bounds();
        return new Rectangle(0, 0, (int)rect.width, (int)rect.height);
    }
}

/**
 * Returns the receiver's horizontal scroll bar if it has
 * one, and null if it does not.
 *
 * @return the horizontal scroll bar (or null)
 *
 * @exception DWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public ScrollBar getHorizontalBar () {
    checkWidget();
    return horizontalBar;
}

/**
 * Returns the receiver's vertical scroll bar if it has
 * one, and null if it does not.
 *
 * @return the vertical scroll bar (or null)
 *
 * @exception DWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public ScrollBar getVerticalBar () {
    checkWidget();
    return verticalBar;
}

bool hooksKeys () {
    return hooks (DWT.KeyDown) || hooks (DWT.KeyUp) || hooks (DWT.Traverse);
}


void releaseHandle () {
    super.releaseHandle ();
    if (scrollView !is null)  {
        scrollView.setTag(-1);
        scrollView.release();
    }
    scrollView = null;
}

void releaseChildren (bool destroy) {
    if (horizontalBar !is null) {
        horizontalBar.release (false);
        horizontalBar = null;
    }
    if (verticalBar !is null) {
        verticalBar.release (false);
        verticalBar = null;
    }
    super.releaseChildren (destroy);
}

void resizeClientArea () {
//  if (scrolledHandle is 0) return;
//  if ((state & CANVAS) is 0) return;
//  int vWidth = 0, hHeight = 0;
//  int [] outMetric = new int [1];
//  OS.GetThemeMetric (OS.kThemeMetricScrollBarWidth, outMetric);
//  bool isVisibleHBar = horizontalBar !is null && horizontalBar.getVisible ();
//  bool isVisibleVBar = verticalBar !is null && verticalBar.getVisible ();
//  if (isVisibleHBar) hHeight = outMetric [0];
//  if (isVisibleVBar) vWidth = outMetric [0];
//  int width, height;
//  CGRect rect = new CGRect (); 
//  OS.HIViewGetBounds (scrolledHandle, rect);
//  width = (int) rect.width;
//  height = (int) rect.height;
//  Rect inset = inset ();
//  width = Math.max (0, width - vWidth - inset.left - inset.right);
//  height = Math.max (0, height - hHeight - inset.top - inset.bottom);
//  setBounds (handle, inset.left, inset.top, width, height, true, true, false);
//  if (isVisibleHBar) {
//      setBounds (horizontalBar.handle, inset.left, inset.top + height, width, hHeight, true, true, false);
//  }
//  if (isVisibleVBar) {
//      setBounds (verticalBar.handle, inset.left + width, inset.top, vWidth, height, true, true, false);
//  }
}

void sendHorizontalSelection () {
    horizontalBar.sendSelection ();
}

bool sendMouseWheel (short wheelAxis, int wheelDelta) {
//  if ((state & CANVAS) !is 0) {
//      ScrollBar bar = wheelAxis is OS.kEventMouseWheelAxisX ? horizontalBar : verticalBar;
//      if (bar !is null && bar.getEnabled ()) {
//          bar.setSelection (Math.max (0, bar.getSelection () - bar.getIncrement () * wheelDelta));
//          Event event = new Event ();
//          event.detail = wheelDelta > 0 ? DWT.PAGE_UP : DWT.PAGE_DOWN;    
//          bar.sendEvent (DWT.Selection, event);
//          return true;
//      }
//  }
    return false;
}

void sendVerticalSelection () {
    verticalBar.sendSelection ();
}

bool setScrollBarVisible (ScrollBar bar, bool visible) {
    if (scrollView is null) return false;
    if ((state & CANVAS) is 0) return false;
    if (visible) {
        if ((bar.state & HIDDEN) is 0) return false;
        bar.state &= ~HIDDEN;
    } else {
        if ((bar.state & HIDDEN) !is 0) return false;
        bar.state |= HIDDEN;
    }
    resizeClientArea ();
//  setVisible (bar.handle, visible);
    bar.sendEvent (visible ? DWT.Show : DWT.Hide);
    sendEvent (DWT.Resize);
    return true;
}

NSView topView () {
    if (scrollView !is null) return scrollView;
    return super.topView ();
}
}