Basic drag'n'drop functionality.

COADocumentWindowController.m

//
//  COADocumentWindowController.m
//  Co-Author
//
//  Created by Christopher Miller on 4/13/12.
//  Copyright (c) 2012 FSDEV. All rights reserved.
//

#import "COADocumentWindowController.h"
#import "COAManagedNode.h"
#import "COAGroupNode.h"
#import "COAFileNode.h"

@interface COADocumentWindowController ()

@end

@implementation COADocumentWindowController

@synthesize drawer=_drawer;
@synthesize outlineView=_outlineView;
@synthesize mutators=_mutators;

@synthesize managedNodes = _managedNodes;

- (IBAction)mutatorClicked:(id)sender {
    switch (_mutators.selectedSegment) {
        case 0:
            [_outlineView beginUpdates];
            [[_outlineView selectedRowIndexes] enumerateIndexesUsingBlock:^(NSUInteger idx, BOOL *stop) {
                id<COAManagedNode> item = [_outlineView itemAtRow:idx];
                id<COAManagedNode> parent = [_outlineView parentForItem:item];
                [_outlineView removeItemsAtIndexes:[NSIndexSet indexSetWithIndex:[[parent children] indexOfObject:item]] inParent:parent withAnimation:NSTableViewAnimationSlideLeft | NSTableViewAnimationEffectFade];
                [[parent children] removeObject:item];
            }];
            [_outlineView endUpdates];
            break;
        case 1:
            NSLog(@"add stuff");
            NSLog(@"%@", _managedNodes);
            break;
        default:
            NSLog(@"no such segment");
            break;
    }
}

#pragma mark NSWindowController

- (id)initWithWindow:(NSWindow *)window
{
    self = [super initWithWindow:window];
    if (self) {
        // Initialization code here.
    }
    
    return self;
}

- (void)windowDidLoad
{
    [super windowDidLoad];
    
    self.managedNodes = [[self document] managedNodes];
    
    [self.drawer openOnEdge:NSMinXEdge];
    [self.outlineView registerForDraggedTypes:[NSArray arrayWithObject:(NSString *)kUTTypeFileURL]];
    [self.outlineView setDraggingSourceOperationMask:NSDragOperationCopy forLocal:NO];
}

#pragma mark NSOutlineViewDataSource

- (id)outlineView:(NSOutlineView *)outlineView child:(NSInteger)index ofItem:(id)item
{
    if (item) {
        id<COAManagedNode> node = item;
        return [[node children] objectAtIndex:index];
    }
    
    return [_managedNodes objectAtIndex:index];
}

- (BOOL)outlineView:(NSOutlineView *)outlineView isItemExpandable:(id)item
{
    if (item) {
        id<COAManagedNode> node = item;
        if ([node isGroup] || [node isDirectory]) return YES;
    }
    
    return NO;
}

- (NSInteger)outlineView:(NSOutlineView *)outlineView numberOfChildrenOfItem:(id)item
{
    if (item == nil) return [_managedNodes count];
    
    else return [((id<COAManagedNode>)item).children count];
}

- (BOOL)outlineView:(NSOutlineView *)outlineView acceptDrop:(id < NSDraggingInfo >)info item:(id)item childIndex:(NSInteger)index
{
    NSPasteboard * pboard = [info draggingPasteboard];
    
    NSMutableArray * proposedNodes = [NSMutableArray arrayWithCapacity:[[pboard pasteboardItems] count]];
    for (NSPasteboardItem * pasteboarditem in [pboard pasteboardItems]) {
        [proposedNodes addObject:[COAFileNode fileNodeWithPath:[pasteboarditem stringForType:(NSString *)kUTTypeFileURL]]];
    }
    
    // eliminate items already managed
    [proposedNodes filterUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(id<COAManagedNode> evaluatedObject, NSDictionary *bindings) {
        return !COAManagedNodePresentInGraph(evaluatedObject, _managedNodes); // don't add nodes already present
    }]];
    
    if (index == -1) index = 0;
    NSIndexSet * insertions = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(index, [proposedNodes count])];
    
    if (item) {
        id<COAManagedNode> managedNode = item;
        [outlineView beginUpdates];
        [outlineView insertItemsAtIndexes:insertions inParent:item withAnimation:NSTableViewAnimationSlideRight | NSTableViewAnimationEffectFade];
        [[managedNode children] insertObjects:proposedNodes atIndexes:insertions];
        [outlineView endUpdates];
    } else {
        [outlineView beginUpdates];
        [outlineView insertItemsAtIndexes:insertions inParent:item withAnimation:NSTableViewAnimationSlideRight | NSTableViewAnimationEffectFade];
        [_managedNodes insertObjects:proposedNodes atIndexes:insertions];
        [outlineView endUpdates];
    }
    
    return YES;
}

- (NSDragOperation)outlineView:(NSOutlineView *)outlineView validateDrop:(id < NSDraggingInfo >)info proposedItem:(id)item proposedChildIndex:(NSInteger)index
{
    if (item != nil && ![((id<COAManagedNode>)item) isGroup]) return NSDragOperationNone;
    
    NSPasteboard * dndPboard = [info draggingPasteboard];
    
    NSMutableArray * proposedNodes = [NSMutableArray arrayWithCapacity:[[dndPboard pasteboardItems] count]];
    for (NSPasteboardItem * pasteboarditem in [dndPboard pasteboardItems])
        [proposedNodes addObject:[COAFileNode fileNodeWithPath:[pasteboarditem stringForType:(NSString *)kUTTypeFileURL]]];
    
    // eliminate items already managed
    [proposedNodes filterUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(id<COAManagedNode> evaluatedObject, NSDictionary *bindings) {
        return !COAManagedNodePresentInGraph(evaluatedObject, _managedNodes); // don't add nodes already present
    }]];
    
    if ([proposedNodes count] == 0) return NSDragOperationNone;
    
    [info setNumberOfValidItemsForDrop:[proposedNodes count]];
    [info setAnimatesToDestination:YES];
    
    return NSDragOperationLink;
}

#pragma mark NSOutlineViewDelegate

- (NSView *)outlineView:(NSOutlineView *)outlineView viewForTableColumn:(NSTableColumn *)tableColumn item:(id)item
{
    NSTableCellView * cell = [outlineView makeViewWithIdentifier:@"FileCell" owner:self];
    id<COAManagedNode> managedNode = item;
    
    if (cell) {
        cell.textField.stringValue = [managedNode name];
        cell.imageView.image = [managedNode icon];
    } else
        NSLog(@"Nil view?");
    
    return cell;
}

@end