/*

 * Copyright (C) 2005 Apple Computer, Inc.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1.  Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer. 

 * 2.  Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in the

 *     documentation and/or other materials provided with the distribution. 

 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of

 *     its contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission. 

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY

 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#import <WebKit/WebDynamicScrollBarsView.h>

#import <WebKit/WebDocument.h>

#import <WebKitSystemInterface.h>

@implementation WebDynamicScrollBarsView

- (void)setSuppressLayout: (BOOL)flag;

{

    suppressLayout = flag;

}

- (void)setScrollBarsSuppressed:(BOOL)suppressed repaintOnUnsuppress:(BOOL)repaint

{

    suppressScrollers = suppressed;

    // This code was originally changes for a Leopard performance imporvement. We decided to 

    // ifdef it to fix correctness issues on Tiger documented in <rdar://problem/5441823>.

#ifndef BUILDING_ON_TIGER

    if (suppressed) {

        [[self verticalScroller] setNeedsDisplay:NO];

        [[self horizontalScroller] setNeedsDisplay:NO];

    }

    if (!suppressed && repaint)

        [super reflectScrolledClipView:[self contentView]];

#else

    if (suppressed || repaint) { 

        [[self verticalScroller] setNeedsDisplay: !suppressed]; 

        [[self horizontalScroller] setNeedsDisplay: !suppressed]; 

    }

#endif

}

- (void)updateScrollers

{

    // We need to do the work below twice in the case where a scroll bar disappears,

    // making the second layout have a wider width than the first. Doing it more than

    // twice would indicate some kind of infinite loop, so we do it at most twice.

    // It's quite efficient to do this work twice in the normal case, so we don't bother

    // trying to figure out of the second pass is needed or not.

    if (inUpdateScrollers)

        return;

    inUpdateScrollers = true;

    int pass;

    BOOL hasVerticalScroller = [self hasVerticalScroller];

    BOOL hasHorizontalScroller = [self hasHorizontalScroller];

    BOOL oldHasVertical = hasVerticalScroller;

    BOOL oldHasHorizontal = hasHorizontalScroller;

    for (pass = 0; pass < 2; pass++) {

        BOOL scrollsVertically;

        BOOL scrollsHorizontally;

        if (!suppressLayout && !suppressScrollers && (hScroll == WebCoreScrollbarAuto || vScroll == WebCoreScrollbarAuto)) {

            // Do a layout if pending, before checking if scrollbars are needed.

            // This fixes 2969367, although may introduce a slowdown in live resize performance.

            NSView *documentView = [self documentView];

            if ((hasVerticalScroller != oldHasVertical ||

                hasHorizontalScroller != oldHasHorizontal || [documentView inLiveResize]) && [documentView conformsToProtocol:@protocol(WebDocumentView)]) {

                [(id <WebDocumentView>)documentView setNeedsLayout: YES];

                [(id <WebDocumentView>)documentView layout];

            }

            NSSize documentSize = [documentView frame].size;

            NSSize frameSize = [self frame].size;

            scrollsVertically = (vScroll == WebCoreScrollbarAlwaysOn) ||

                (vScroll == WebCoreScrollbarAuto && documentSize.height > frameSize.height);

            if (scrollsVertically)

                scrollsHorizontally = (hScroll == WebCoreScrollbarAlwaysOn) ||

                    (hScroll == WebCoreScrollbarAuto && documentSize.width + [NSScroller scrollerWidth] > frameSize.width);

            else {

                scrollsHorizontally = (hScroll == WebCoreScrollbarAlwaysOn) ||

                    (hScroll == WebCoreScrollbarAuto && documentSize.width > frameSize.width);

                if (scrollsHorizontally)

                    scrollsVertically = (vScroll == WebCoreScrollbarAlwaysOn) ||

                        (vScroll == WebCoreScrollbarAuto && documentSize.height + [NSScroller scrollerWidth] > frameSize.height);

            }

        } else {

            scrollsHorizontally = (hScroll == WebCoreScrollbarAuto) ? hasHorizontalScroller : (hScroll == WebCoreScrollbarAlwaysOn);

            scrollsVertically = (vScroll == WebCoreScrollbarAuto) ? hasVerticalScroller : (vScroll == WebCoreScrollbarAlwaysOn);

        }

        if (hasVerticalScroller != scrollsVertically) {

            [self setHasVerticalScroller:scrollsVertically];

            hasVerticalScroller = scrollsVertically;

        }

        if (hasHorizontalScroller != scrollsHorizontally) {

            [self setHasHorizontalScroller:scrollsHorizontally];

            hasHorizontalScroller = scrollsHorizontally;

        }

    }

    if (suppressScrollers) {

        [[self verticalScroller] setNeedsDisplay: NO];

        [[self horizontalScroller] setNeedsDisplay: NO];

    }

    inUpdateScrollers = false;

}

// Make the horizontal and vertical scroll bars come and go as needed.

- (void)reflectScrolledClipView:(NSClipView *)clipView

{

    if (clipView == [self contentView]) {

        // FIXME: This hack here prevents infinite recursion that takes place when we

        // gyrate between having a vertical scroller and not having one. A reproducible

        // case is clicking on the "the Policy Routing text" link at

        // http://www.linuxpowered.com/archive/howto/Net-HOWTO-8.html.

        // The underlying cause is some problem in the NSText machinery, but I was not

        // able to pin it down.

        if (!inUpdateScrollers && [[NSGraphicsContext currentContext] isDrawingToScreen])

            [self updateScrollers];

    }

    // This code was originally changed for a Leopard performance imporvement. We decided to 

    // ifdef it to fix correctness issues on Tiger documented in <rdar://problem/5441823>.

#ifndef BUILDING_ON_TIGER

    // Update the scrollers if they're not being suppressed.

    if (!suppressScrollers)

        [super reflectScrolledClipView:clipView];

#else

    [super reflectScrolledClipView:clipView]; 

    // Validate the scrollers if they're being suppressed. 

    if (suppressScrollers) { 

        [[self verticalScroller] setNeedsDisplay: NO]; 

        [[self horizontalScroller] setNeedsDisplay: NO]; 

    }

#endif

}

- (void)setAllowsScrolling:(BOOL)flag

{

    if (hScrollModeLocked && vScrollModeLocked)

        return;

    if (flag && vScroll == WebCoreScrollbarAlwaysOff)

        vScroll = WebCoreScrollbarAuto;

    else if (!flag && vScroll != WebCoreScrollbarAlwaysOff)

        vScroll = WebCoreScrollbarAlwaysOff;

    if (flag && hScroll == WebCoreScrollbarAlwaysOff)

        hScroll = WebCoreScrollbarAuto;

    else if (!flag && hScroll != WebCoreScrollbarAlwaysOff)

        hScroll = WebCoreScrollbarAlwaysOff;

    [self updateScrollers];

}

- (BOOL)allowsScrolling

{

    // Returns YES if either horizontal or vertical scrolling is allowed.

    return hScroll != WebCoreScrollbarAlwaysOff || vScroll != WebCoreScrollbarAlwaysOff;

}

- (void)setAllowsHorizontalScrolling:(BOOL)flag

{

    if (hScrollModeLocked)

        return;

    if (flag && hScroll == WebCoreScrollbarAlwaysOff)

        hScroll = WebCoreScrollbarAuto;

    else if (!flag && hScroll != WebCoreScrollbarAlwaysOff)

        hScroll = WebCoreScrollbarAlwaysOff;

    [self updateScrollers];

}

- (void)setAllowsVerticalScrolling:(BOOL)flag

{

    if (vScrollModeLocked)

        return;

    if (flag && vScroll == WebCoreScrollbarAlwaysOff)

        vScroll = WebCoreScrollbarAuto;

    else if (!flag && vScroll != WebCoreScrollbarAlwaysOff)

        vScroll = WebCoreScrollbarAlwaysOff;

    [self updateScrollers];

}

- (BOOL)allowsHorizontalScrolling

{

    return hScroll != WebCoreScrollbarAlwaysOff;

}

- (BOOL)allowsVerticalScrolling

{

    return vScroll != WebCoreScrollbarAlwaysOff;

}

-(WebCoreScrollbarMode)horizontalScrollingMode

{

    return hScroll;

}

-(WebCoreScrollbarMode)verticalScrollingMode

{

    return vScroll;

}

- (void)setHorizontalScrollingMode:(WebCoreScrollbarMode)mode

{

    [self setHorizontalScrollingMode:mode andLock:NO];

}

- (void)setHorizontalScrollingMode:(WebCoreScrollbarMode)mode andLock:(BOOL)lock

{

    if (mode == hScroll || hScrollModeLocked)

        return;

    hScroll = mode;

    if (lock)

        [self setHorizontalScrollingModeLocked:YES];

    [self updateScrollers];

}

- (void)setVerticalScrollingMode:(WebCoreScrollbarMode)mode

{

    [self setVerticalScrollingMode:mode andLock:NO];

}

- (void)setVerticalScrollingMode:(WebCoreScrollbarMode)mode andLock:(BOOL)lock

{

    if (mode == vScroll || vScrollModeLocked)

        return;

    vScroll = mode;

    if (lock)

        [self setVerticalScrollingModeLocked:YES];

    [self updateScrollers];

}

- (void)setScrollingMode:(WebCoreScrollbarMode)mode

{

    [self setScrollingMode:mode andLock:NO];

}

- (void)setScrollingMode:(WebCoreScrollbarMode)mode andLock:(BOOL)lock

{

    if ((mode == vScroll && mode == hScroll) || (vScrollModeLocked && hScrollModeLocked))

        return;

    BOOL update = NO;

    if (mode != vScroll && !vScrollModeLocked) {

        vScroll = mode;

        update = YES;

    }

    if (mode != hScroll && !hScrollModeLocked) {

        hScroll = mode;

        update = YES;

    }

    if (lock)

        [self setScrollingModesLocked:YES];

    if (update)

        [self updateScrollers];

}

- (void)setHorizontalScrollingModeLocked:(BOOL)locked

{

    hScrollModeLocked = locked;

}

- (void)setVerticalScrollingModeLocked:(BOOL)locked

{

    vScrollModeLocked = locked;

}

- (void)setScrollingModesLocked:(BOOL)locked

{

    hScrollModeLocked = vScrollModeLocked = locked;

}

- (BOOL)horizontalScrollingModeLocked

{

    return hScrollModeLocked;

}

- (BOOL)verticalScrollingModeLocked

{

    return vScrollModeLocked;

}

- (BOOL)autoforwardsScrollWheelEvents

{

    return YES;

}

- (void)scrollWheel:(NSEvent *)event

{

    float deltaX;

    float deltaY;

    BOOL isContinuous;

    WKGetWheelEventDeltas(event, &deltaX, &deltaY, &isContinuous);

    if (fabsf(deltaY) > fabsf(deltaX)) {

        if (![self allowsVerticalScrolling]) {

            [[self nextResponder] scrollWheel:event];

            return;

        }

    } else if (![self allowsHorizontalScrolling]) {

        [[self nextResponder] scrollWheel:event];

        return;

    }

    [super scrollWheel:event];

}

@end