ColumnViewController.m #1

//
//  ColumnViewController.m
//  Perforce
//
//  Created by Adam Czubernat on 12.05.2013.
//  Copyright (c) 2013 Perforce Software, Inc. All rights reserved.
//

#import "ColumnViewController.h"
#import "ColumnCell.h"

#import "PSBrowser.h"

#import "ColumnViewDetails.h"
#import "ColumnViewHeader.h"

@interface ColumnViewController () <PSBrowserDelegate, ColumnViewHeaderDelegate, QLPreviewPanelDataSource, QLPreviewPanelDelegate, NSMenuDelegate> {
	__weak IBOutlet PSBrowser *browserView;

	IBOutlet NSView *loadingOverlay;
	__weak IBOutlet NSProgressIndicator *loadingOverlayIndicator;
	NSProgressIndicator *progressIndicator;
	PSView *warningIndicator;
	
	id loadingItem;
	
	// Selected details
	P4Item *detailsItem;
	
	// Selected header
	P4Item *headerItem;
	ColumnViewHeader *headerController;
	
	NSMutableArray *columnHeaders;
	
	// Will Load
	NSString *reloadPath;
	NSArray *reloadSelection;
	CGFloat reloadScroll;
	ColumnViewHeader *reloadHeader;
	
	// QuickLook
	QLPreviewPanel *quickLookPanel;
	NSArray *quickLookItems;
}
- (void)clickAction;
- (void)doubleClickAction;
- (void)selectionChangedToItem:(P4Item *)item;
- (void)deselectHeader;
- (void)showLoadingOverlay;
- (void)showLoadingForItem:(P4Item *)item;
- (void)showErrorForItem:(P4Item *)item;

- (void)updateFavoritesNotification:(NSNotification *)notification;
@end

@implementation ColumnViewController

- (void)loadView {
	[super loadView];
	
	[browserView setBackgroundColor:[NSUserDefaults colorForKey:
									 kColorBackgroundColumnContainer]];
	[browserView setCellClass:[ColumnCell class]];
	[browserView setRowHeight:24.0f];
	
    [browserView setSendsActionOnArrowKeys:YES];
	[browserView setAllowsMultipleSelection:YES];
	[browserView setAllowsBranchSelection:YES];
	
	[browserView registerForDraggedTypes:@[ NSFilenamesPboardType ]];
	[browserView setDraggingSourceOperationMask:NSDragOperationEvery forLocal:YES];
    [browserView setDraggingSourceOperationMask:NSDragOperationEvery forLocal:NO];

	[browserView setTarget:self];
	[browserView setAction:@selector(clickAction)];
	[browserView setDoubleAction:@selector(doubleClickAction)];
	
	[browserView setFocusRingType:NSFocusRingTypeNone];
	[(id)browserView setBorderType:NSNoBorder];
	
	[[NSNotificationCenter defaultCenter]
	 addObserver:self selector:@selector(updateFavoritesNotification:)
	 name:P4WorkspaceDefaultsChangedNotification
	 object:nil];
}

- (void)dealloc {
	[[NSNotificationCenter defaultCenter]
	 removeObserver:self
	 name:P4WorkspaceDefaultsChangedNotification
	 object:nil];
}

#pragma mark - BrowserViewController Overrides

- (NSArray *)selectedItems {
	NSMutableArray *array = [NSMutableArray array];
	for (NSIndexPath *indexPath in [browserView selectionIndexPaths]) {
		P4Item *item = [browserView itemAtIndexPath:indexPath];
		[array addObject:item];
	}
	return array;
}

- (void)setRootItem:(P4Item *)item {
	[super setRootItem:item];
	[self deselectHeader];
	
	[browserView loadColumnZero];
}

- (void)setWorkingItem:(P4Item *)item {
	[super setWorkingItem:item];
	[self selectionChangedToItem:item];
	
	[self deselectHeader];
	
	if (!workingItem)
		return;
	
	NSString *rootPath = rootItem.path;
	NSString *relative = [workingItem.path stringByRemovingPrefix:rootPath];
	[browserView loadColumnZero];
	[browserView setPath:relative];
}

- (void)setSelectedIndexes:(NSIndexSet *)indexes {
	[browserView selectRowIndexes:indexes inColumn:browserView.lastColumn];
	[self clickAction];
}

- (void)refresh {
	[browserView setNeedsDisplay];
}

- (void)willLoadPath:(NSString *)path {
	
	[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(showLoadingOverlay) object:nil];
	[self performSelector:@selector(showLoadingOverlay) withObject:nil afterDelay:0.25f];
	
	reloadPath = path;
	if (isReloading) {
		
		// Get scrollview position
		NSScrollView *scrollView = nil;
		for (NSView *subview in [browserView subviews])
			if ([subview isKindOfClass:NSClassFromString(@"_NSBrowserScrollView")])
				scrollView = (id)subview;
		reloadScroll = [scrollView documentVisibleRect].origin.x;
		
		reloadSelection = [[self selectedItems] valueForKey:@"path"];
		reloadHeader = headerController;
	}
}

- (void)showVersions:(P4Item *)item {
	
	if (item != detailsItem) {
		[browserView selectRow:[browserView clickedRow] inColumn:[browserView clickedColumn]];
		[self clickAction];
	}
	
	ColumnViewDetails *details = (id)[browserView detailViewController];
	[details showVersions];
}

- (void)editItemName:(P4Item *)item {
    NSInteger row = [[item.parent children] indexOfObjectIdenticalTo:item];
    NSIndexPath *indexPath = [browserView indexPathForColumn:[browserView lastColumn]];
    indexPath = [indexPath indexPathByAddingIndex:row];

    [browserView setSelectionIndexPath:indexPath];
    [browserView editItemAtIndexPath:indexPath withEvent:nil select:NO];

    [self selectionChangedToItem:item];
}

#pragma mark - Private

- (void)clickAction {
		
	NSArray *selection = [self selectedItems];
	
	if (!quickLookPanel && [QLPreviewPanel sharedPreviewPanelExists])
		[[QLPreviewPanel sharedPreviewPanel] updateController];
	if (quickLookPanel) {
		quickLookItems = selection;
		[quickLookPanel reloadData];
	}
	
	if (selection.count > 1)
		return; // Don't show details for multiple items
		
	P4Item *item = selection.lastObject ?: rootItem;
	[self selectionChangedToItem:item];
		
	// Show detail pane for files
	if (item && ![item isDirectory]) {
		ColumnViewDetails *detailsController;
		detailsController = [[ColumnViewDetails alloc] initWithItem:item
							 actionDelegate:[self.view.window windowController]];
		[browserView setDetailViewController:detailsController];
		detailsItem = item;
	}
}

- (void)doubleClickAction {
	
	if (browserView.selectionIndexPaths.count > 1)
		return; // Don't open multiple items

	P4Item *item = [browserView itemAtIndexPath:browserView.selectionIndexPath];
	if (!item)
		return;

	[self selectionChangedToItem:item];

	// Perform default item action
	P4ItemAction *action = [item defaultAction];
	action.delegate = [self.view.window windowController];
	[action performAction];
}

- (void)selectionChangedToItem:(P4Item *)item {
	
	[self deselectHeader];
	
//	// Auto mark as unread
//	if (!item.isDirectory && item.isUpdated)
//		[item markAsRead];

	// Get parent if item is not expandable
	P4Item *nodeItem = [item isDirectory] ? item : [item parent];
	if (workingItem != nodeItem)
		[super setWorkingItem:nodeItem];

	[self selectionChanged:item];
}

- (void)deselectHeader {
	[headerController setSelected:NO];
	headerController = nil;
	headerItem = nil;
}

- (void)showLoadingOverlay {
	[loadingOverlay setFrame:self.view.bounds];
	[self.view addSubview:loadingOverlay];
	[loadingOverlayIndicator startAnimation:nil];
}

- (void)showLoadingForItem:(P4Item *)item {
	[progressIndicator removeFromSuperview];
	if (!item.isLoading)
		return;
	
	loadingItem = item;
	if (!progressIndicator) {
		progressIndicator = [[NSProgressIndicator alloc] init];
		[progressIndicator setStyle:NSProgressIndicatorSpinningStyle];
		[progressIndicator setIndeterminate:YES];
		[progressIndicator setControlSize:NSRegularControlSize];
	}
	
	NSArray *columns = [browserView valueForKey:@"_columns"];
	NSView *columnView = [columns objectAtIndex:browserView.lastColumn];
	
	CGRect frame = columnView.frame;
	frame.origin.x += (frame.size.width - 32.0f)/2.0f;
	frame.origin.y += (frame.size.height - 32.0f)/2.0f;
	frame.size.width = frame.size.height = 32.0f;
	progressIndicator.frame = frame;
	[progressIndicator setAutoresizing:NSViewAutoresizingLeftEdge];
	
	[progressIndicator startAnimation:nil];
	[columnView.superview addSubview:progressIndicator];
}

- (void)showErrorForItem:(P4Item *)item {
	[warningIndicator removeFromSuperview];
	if (!item.hasError)
		return;
	
	static NSImage *warningImage;
	if (!warningImage)
		warningImage = [NSImage imageNamed:@"Warning.png"];
	
	NSArray *columns = [browserView valueForKey:@"_columns"];
	NSView *columnView = columns.count ? [columns objectAtIndex:browserView.lastColumn] : browserView;
	
	CGRect frame = columns.count ? columnView.frame : [browserView frameOfColumn:0];
	frame.origin.x += (frame.size.width - 32.0f)/2.0f;
	frame.origin.y += (frame.size.height - 32.0f)/2.0f;
	frame.size.width = frame.size.height = 32.0f;
	
	if (!warningIndicator) {
		warningIndicator = [[PSView alloc] init];
		warningIndicator.image = warningImage;
		[warningIndicator setAutoresizing:NSViewAutoresizingLeftEdge];
	}
	warningIndicator.frame = frame;
	[columnView.superview addSubview:warningIndicator];
}

#pragma mark - P4WorkspaceDefaults Notification

- (void)updateFavoritesNotification:(NSNotification *)notification {
	if ([detailsItem isDirectory])
		[self itemDidLoad:detailsItem];
}

#pragma mark - NSBrowser delegate

- (id)rootItemForBrowser:(NSBrowser *)browser {
	return rootItem;
}

- (NSInteger)browser:(NSBrowser *)browser numberOfChildrenOfItem:(P4Item *)item {
	return item.children.count;
}

- (id)browser:(NSBrowser *)browser child:(NSInteger)index ofItem:(P4Item *)item {
	NSArray *children = item.children;
	if (index < children.count)
		return [children objectAtIndex:index];	
	return nil;
}

- (BOOL)browser:(NSBrowser *)browser isLeafItem:(P4Item *)item {
	return !item.isDirectory;
}

- (id)browser:(NSBrowser *)browser objectValueForItem:(P4Item *)item {
	return item.name;
}

- (void)browser:(NSBrowser *)sender willDisplayCell:(ColumnCell *)cell atRow:(NSInteger)row column:(NSInteger)column {;
	P4Item *item = [browserView itemAtRow:row inColumn:column];
	
	cell.image = item.icon;
	cell.selectedImage = item.iconHighlighted;
	
	[cell setLeaf:![item isDirectory]];

	cell.unread = item.isUnread;
	cell.tag = [self hasFilteredTagsForItem:item];
	
	static NSColor *shelvedColor;
	if (!shelvedColor)
		shelvedColor = [NSColor colorWithHexString:@"#f2c600"];
	cell.overlayColor = item.isShelved ? shelvedColor : item.overlay;
}

- (void)browser:(NSBrowser *)browser didChangeLastColumn:(NSInteger)oldLastColumn toColumn:(NSInteger)column {
	if (column < 0)
		return;
	
	P4Item *item = [browser parentForItemsInColumn:column];
	[self showLoadingForItem:item];
	[self showErrorForItem:item];
}

- (NSViewController *)browser:(NSBrowser *)browser headerViewControllerForItem:(P4Item *)item {
	
	if (item == rootItem)
		return nil;
	
	ColumnViewHeader *header = [[ColumnViewHeader alloc] init];
	header.delegate = self;
	if (headerItem == item) { // New header should be selected
		headerController = header;
		header.selected = YES;
	}
	
	// Get column number from parent count
	NSInteger column = 0;
	for (P4Item *parent = item.parent; parent; column++, parent = parent.parent);
	
	if (!columnHeaders)
		columnHeaders = [NSMutableArray array];
	
	if (column-1 < columnHeaders.count)
		[columnHeaders replaceObjectAtIndex:column-1 withObject:header];
	else
		[columnHeaders addObject:header];

	
	return header;
}

- (BOOL)browser:(NSBrowser *)browser shouldEditItem:(P4Item *)item {
	return [item isEditable];
}

- (void)browser:(NSBrowser *)browser setObjectValue:(NSString *)value forItem:(P4Item *)item {
	[self renameItem:item name:value];
}

#pragma mark Keyboard support

- (void)browserDidReceiveCommandDeleteKey:(NSBrowser *)browser {
	if (![browserView selectionIndexPath])
		return;
		
	NSArray *selectedItems = [self selectedItems];
	[rootItem performAction:@selector(deleteItems:)
					  items:selectedItems
				   delegate:[self.view.window windowController]];
}

- (void)browserDidReceiveSpacebarKey:(NSBrowser *)browser {
	
	QLPreviewPanel *previewPanel = [QLPreviewPanel sharedPreviewPanel];
	// Dismiss if visible
	if ([QLPreviewPanel sharedPreviewPanelExists] && [previewPanel isVisible]) {
		[previewPanel orderOut:nil];
		return;
	}
	
	if (![browserView selectionIndexPath])
		return;

	[previewPanel updateController];
	[previewPanel makeKeyAndOrderFront:nil];
}

#pragma mark - Drag and Drop support

- (BOOL)browser:(NSBrowser *)browser writeRowsWithIndexes:(NSIndexSet *)rowIndexes inColumn:(NSInteger)column toPasteboard:(NSPasteboard *)pasteboard {
    
    NSMutableArray *filenames = [NSMutableArray array];
	[rowIndexes enumerateIndexesUsingBlock:^(NSUInteger idx, BOOL *stop) {
		P4Item *item = [browser itemAtRow:idx inColumn:column];
		if ([item isEditable])
			[filenames addObject:item.localPath];
	}];
	
    [pasteboard declareTypes:@[NSFilenamesPboardType] owner:self];
    [pasteboard setPropertyList:filenames forType:NSFilenamesPboardType];
    return YES;
}

- (BOOL)browser:(NSBrowser *)browser canDragRowsWithIndexes:(NSIndexSet *)rowIndexes inColumn:(NSInteger)column withEvent:(NSEvent *)event {
	NSMutableArray *items = [NSMutableArray array];
	[rowIndexes enumerateIndexesUsingBlock:^(NSUInteger idx, BOOL *stop) {
		P4Item *item = [browser itemAtRow:idx inColumn:column];
		if ([item isEditable])
			[items addObject:item];
	}];
	
    return items.count;
}

- (NSImage *)browser:(NSBrowser *)browser draggingImageForRowsWithIndexes:(NSIndexSet *)rowIndexes inColumn:(NSInteger)column withEvent:(NSEvent *)event offset:(NSPointPointer)dragImageOffset {
    NSImage *result = [browser draggingImageForRowsWithIndexes:rowIndexes inColumn:column withEvent:event offset:dragImageOffset];
    PSLog(@"");
	[result lockFocus];
	if (rowIndexes.count > 1) {
				
		NSPoint mouse = (CGPoint) {
			result.size.width * 0.5f - dragImageOffset->x,
			result.size.height * 0.5f - dragImageOffset->y,
		};
		
        NSShadow *shadow = [[NSShadow alloc] init];
        [shadow setShadowOffset:NSMakeSize(0.5, 0.5)];
        [shadow setShadowBlurRadius:5.0];
        [shadow setShadowColor:[NSColor blackColor]];

        NSDictionary *attrs = @{
			NSShadowAttributeName : shadow,
			NSForegroundColorAttributeName : [NSColor whiteColor],
		};
		
		NSInteger cornerSize = 10.0f;
		NSGradient *gradient = [[NSGradient alloc]
								initWithStartingColor:[NSColor colorWithHexString:@"#FCC"]
								endingColor:[NSColor redColor]];
		NSBezierPath *bezier = [NSBezierPath
								bezierPathWithRoundedRect:(CGRect) { mouse, {20.0f, 20.0f} }
								xRadius:cornerSize
								yRadius:cornerSize];
		[gradient drawInBezierPath:bezier angle:90.0f];
		
		BOOL copy = [[NSApp currentEvent] modifierFlags] & NSAlternateKeyMask;
		NSString *str = [NSString stringWithFormat:@"%@%ld", copy ? @"+": @"", rowIndexes.count];
        NSAttributedString *attrStr = [[NSAttributedString alloc] initWithString:str attributes:attrs];
        [attrStr drawAtPoint:(CGPoint) {
			mouse.x + (20.0f - attrStr.size.width) / 2.0f,
			mouse.y + (20.0f - attrStr.size.height) / 2.0f + 1,
		}];
		[result unlockFocus];
    }
    return result;
}

- (NSDragOperation)browser:(NSBrowser *)browser validateDrop:(id <NSDraggingInfo>)info proposedRow:(NSInteger *)row column:(NSInteger *)column dropOperation:(NSBrowserDropOperation *)dropOperation {
	
	NSDragOperation operation = NSDragOperationEvery;

	// Check if option key is pressed
	if ([[NSApp currentEvent] modifierFlags] & NSAlternateKeyMask)
		operation = NSDragOperationCopy;
		
    // Accept only file types
    if ([[[info draggingPasteboard] types] indexOfObject:NSFilenamesPboardType] == -1)
		return NSDragOperationNone;
	
	if (*column == -1)
		return NSDragOperationNone;
	
	P4Item *parent = [browserView parentForItemsInColumn:*column];
	NSInteger rows = parent.children.count;
	
	if (*dropOperation == NSBrowserDropAbove) {
		if (*row < rows) {
			*row = -1;
			return NSDragOperationNone;
		}
		*row = -1;
		return operation;
	}
	
	P4Item *target = [browserView itemAtRow:*row inColumn:*column];
			
	if (![target isDirectory] || ![target isEditable]) {
		// Can't drop onto a file. Retarget to the column
		*row = -1;
		*dropOperation = NSBrowserDropOn;
		
		if (![parent isEditable])
			return NSDragOperationNone;			
	}
	
	return operation;
}

- (BOOL)browser:(NSBrowser *)browser acceptDrop:(id <NSDraggingInfo>)info atRow:(NSInteger)row column:(NSInteger)column dropOperation:(NSBrowserDropOperation)dropOperation {

	// Check if option key is pressed
	BOOL copy = info.draggingSourceOperationMask == NSDragOperationCopy;

	NSArray *paths = [info.draggingPasteboard propertyListForType:NSFilenamesPboardType];
	
    if (column == -1 || !paths.count)
		return NO;
	
	// Find the target folder
	P4Item *target = nil;
	
	if (row == -1)
		target = [browser parentForItemsInColumn:column];
	else
		target = [browser itemAtRow:row inColumn:column];
		
	return [self insertFiles:paths intoItem:target copy:copy];
}

#pragma mark - ColumnHeader delegate

- (void)columnViewHeader:(ColumnViewHeader *)header clickedWithItem:(P4Item *)item {

	[[browserView window] makeFirstResponder:browserView]; 	// Conclude editing
	
	// Get column number from parent count
	NSInteger column = 0;
	for (P4Item *parent = item.parent; parent; column++, parent = parent.parent);

	if (browserView.lastColumn == column) {
		// Change is inside current parent. Select parent row in previous column
		NSUInteger row = [browserView selectedRowInColumn:column-1];

		// Store item for selection because new header will be created
		headerItem = item;
		[browserView selectRow:row inColumn:column-1];

		[self selectionChanged:item];
		
	} else {
	
		[[browserView animator] setLastColumn:column]; // Trim selection to header's parent
		[self selectionChangedToItem:item];

		// Store selected header as selected
		headerItem = item;
		headerController = header;
	}
	
	// Stop indicator
	if (item == loadingItem) {
		loadingItem = nil;
		[progressIndicator stopAnimation:nil];
		[progressIndicator removeFromSuperview];
	}
	
	// Show details for header's folder
	ColumnViewDetails *detailsController;
	detailsController = [[ColumnViewDetails alloc]
						 initWithItem:item
						 actionDelegate:[self.view.window windowController]];
	[browserView setDetailViewController:detailsController];
	detailsItem = item;
}

#pragma mark - P4Item delegate

- (void)itemDidLoad:(P4Item *)item {
	[super itemDidLoad:item];
	
	// Remove loading indicator
	if (item == loadingItem) {
		loadingItem = nil;
		[progressIndicator stopAnimation:nil];
		[progressIndicator removeFromSuperview];
	}
	
	if (isLoading) {
		
		[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(showLoadingOverlay) object:nil];
		[loadingOverlay removeFromSuperview];
		
		P4Item *item = [rootItem cachedItemForPath:reloadPath];
		if (!item) {
			[self failWithError:
			 [NSError errorWithFormat:@"Couldn't find file at %@", reloadPath]];
			isLoading = isReloading = NO;
			return;
		}
		
		isLoading = NO;
		[self setSelectedItems:@[ item ]];
		
		if (isReloading) {
			isReloading = NO;
				
			// Find items for previously selected paths
			NSInteger idx = 0;
			NSMutableIndexSet *indexes = [NSMutableIndexSet indexSet];
			for (P4Item *child in item.children) {
				if ([reloadSelection containsObject:child.path])
					[indexes addIndex:idx];
				idx++;
			}
			[browserView selectRowIndexes:indexes inColumn:browserView.lastColumn];
			
			// Set scrollview's position
			NSScrollView *scrollView = nil;
			for (NSView *subview in [browserView subviews])
				if ([subview isKindOfClass:NSClassFromString(@"_NSBrowserScrollView")])
					scrollView = (id)subview;
			[scrollView scrollClipView:scrollView.contentView toPoint:CGPointMake(reloadScroll, 0.0)];
			
			if (reloadHeader)
				[self columnViewHeader:reloadHeader clickedWithItem:item];
			else
				[self clickAction];
		}
		return;
	}
		
	// Redisplay (for name, icon, overlay changes)
	[browserView setNeedsDisplay:YES];
	
	// Redisplay detail view
	if (detailsItem == item && [browserView detailViewController]) {
		ColumnViewDetails *detailsController;
		detailsController = [[ColumnViewDetails alloc]
							 initWithItem:item
							 actionDelegate:[self.view.window windowController]];
		[browserView setDetailViewController:detailsController];
	}
	
	// Directory change
	if ([item isDirectory]) {

		// Get column number from parent count
		NSInteger column = 0;
		for (P4Item *parent = item.parent; parent; column++, parent = parent.parent);
			
		if (column > browserView.lastColumn)
			return;		
		if (item != [browserView parentForItemsInColumn:column])
			return;
		
		// Reload children
		[browserView reloadColumn:column];
		
//		// Refresh navigation
//		id lastItem = [navigationController lastItem];
//		[navigationController removeLastItem];
//		[navigationController setLastItem:lastItem];
	
		// Refresh column header
		if (column > 0)
			[[columnHeaders objectAtIndex:column-1] setRepresentedObject:item];
	}
}

- (void)itemDidInvalidate:(P4Item *)item {

	if (item == detailsItem)
		[browserView setDetailViewController:nil];	
}

- (void)item:(id)item didFailWithError:(NSError *)error {
	[self failWithError:error];
	[self itemDidLoad:item];
	[self showErrorForItem:item];
	
	PSLog(@"ColumnView error: %@", error.localizedDescription);
}

#pragma mark - Quicklook Panel delegate

- (BOOL)acceptsPreviewPanelControl:(QLPreviewPanel *)panel {
    return YES;
}

- (void)beginPreviewPanelControl:(QLPreviewPanel *)panel {
	quickLookPanel = panel;
    panel.delegate = self;
    panel.dataSource = self;
}

- (void)endPreviewPanelControl:(QLPreviewPanel *)panel {
	quickLookPanel = nil;
}

- (BOOL)previewPanel:(QLPreviewPanel *)panel handleEvent:(NSEvent *)event {
    // Redirect all key down events to the browser
    if ([event type] == NSKeyDown) {
        [browserView keyDown:event];
        return YES;
    }
    return NO;
}

- (NSInteger)numberOfPreviewItemsInPreviewPanel:(QLPreviewPanel *)panel {
	quickLookItems = [self selectedItems];
    return quickLookItems.count;
}

- (id <QLPreviewItem>)previewPanel:(QLPreviewPanel *)panel previewItemAtIndex:(NSInteger)index {
    return [quickLookItems objectAtIndex:index];
}

- (NSRect)previewPanel:(QLPreviewPanel *)panel sourceFrameOnScreenForPreviewItem:(id <QLPreviewItem>)item {
    
	NSIndexPath *indexPath = [browserView selectionIndexPath];
	if (!indexPath)
		return CGRectZero;
	
	// Calculate selected cell's image frame
	NSUInteger row = [indexPath indexAtPosition:indexPath.length-1];
    CGRect cellRect = [browserView frameOfRow:row inColumn:indexPath.length-1];
	NSCell *cell = [browserView selectedCellInColumn:browserView.selectedColumn];
	CGRect imageRect = [cell imageRectForBounds:cellRect];
	CGRect columnRect = [browserView frameOfColumn:indexPath.length-1];
	imageRect.origin.x += columnRect.origin.x;
	imageRect.origin.y += columnRect.origin.y;
	
    // Check that the icon rect is visible on screen
    CGRect visibleRect = [browserView visibleRect];
    if (!NSIntersectsRect(visibleRect, imageRect))
        return CGRectZero;
    
    // Convert icon rect to screen coordinates
    imageRect = [browserView convertRectToBase:imageRect];
    imageRect.origin = [[browserView window] convertBaseToScreen:imageRect.origin];
	
    return imageRect;
}

- (id)previewPanel:(QLPreviewPanel *)panel transitionImageForPreviewItem:(id <QLPreviewItem>)previewItem contentRect:(NSRect *)contentRect {
	P4Item *item = (P4Item *)previewItem;
    return item.iconHighlighted;
}

#pragma mark - Menu delegate

- (void)menuWillOpen:(NSMenu *)menu {
	[menu setAllowsContextMenuPlugIns:NO];
	
	NSInteger col = [browserView clickedColumn];
	NSInteger row = [browserView clickedRow];
	NSIndexSet *set = [browserView selectedRowIndexesInColumn:col];
	P4Item *item = nil;
	if (set.count > 1 && [set containsIndex:row]) {
		item = [browserView parentForItemsInColumn:col]; // Multiple
		[menu setItems:[item.children objectsAtIndexes:set]
			  delegate:[self.view.window windowController]];
		return;
	} else if (col >= 0) {
		if (row < 0)
			item = [browserView parentForItemsInColumn:col];
		else
			item = [browserView itemAtRow:row inColumn:col];
	}
	[menu setItem:item delegate:[self.view.window windowController]];
}

@end