/*

     File: TransactionsController_Dragging.m

 Abstract: This category implements tableView data source methods to support dragging.

  Version: 1.2

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 */

#import "TransactionsController.h"

#import "MyDocument_Pasteboard.h"

@implementation TransactionsController(Dragging)

/* Preliminary registration */

- (void)awakeFromNib {

    [_transactionTable registerForDraggedTypes:[_document readablePasteboardTypes]];

    [_transactionTable setDraggingSourceOperationMask:(NSDragOperationCopy|NSDragOperationGeneric) forLocal:YES];

    [_transactionTable setDraggingSourceOperationMask:(NSDragOperationCopy|NSDragOperationGeneric) forLocal:NO];

}

/* Data source methods for dragging out */

- (BOOL)tableView:(NSTableView *)tv writeRowsWithIndexes:(NSIndexSet *)rowIndexes toPasteboard:(NSPasteboard *)pboard {

    // This method will be called before the start of a drag out

    BOOL result = NO;

    if (NSNotFound != [rowIndexes firstIndex]) {

        // We ask the document to write out the selected transactions plus a file promise to the pasteboard

        [self setSelectionIndexes:rowIndexes];

        result = [_document writeSelectionToPasteboard:pboard types:[_document writablePasteboardTypes]];

    }

    return result;

}

- (NSArray *)tableView:(NSTableView *)tv namesOfPromisedFilesDroppedAtDestination:(NSURL *)dropDestination forDraggedRowsWithIndexes:(NSIndexSet *)rowIndexes {

    // This method will be called if we need to redeem our file promise

    NSURL *fileURL = nil;

    if (dropDestination && NSNotFound != [rowIndexes firstIndex]) {

        // We ask the document to write out the selected transactions to a file in the specified directory

        [self setSelectionIndexes:rowIndexes];

        fileURL = [_document writeSelectionToDestination:dropDestination];

    }

    return (fileURL ? [NSArray arrayWithObject:[[fileURL path] lastPathComponent]] : nil);

}

/* Data source methods for dragging in */

- (NSDragOperation)tableView:(NSTableView *)tv validateDrop:(id <NSDraggingInfo>)info proposedRow:(NSInteger)row proposedDropOperation:(NSTableViewDropOperation)op {

    // This method will be called repeatedly during a drag in, to validate it and to determine the operation type and drop location

    NSDragOperation result = NSDragOperationNone, mask = [info draggingSourceOperationMask];

    NSArray *availableTypes = [[info draggingPasteboard] types], *readableTypes = [_document readablePasteboardTypes];

    NSEnumerator *enumerator = [readableTypes objectEnumerator];

    NSString *type;

    // We always copy, but if source and destination are the same, then we do not accept the drag unless the user explicitly chooses copy

    if (tv != [info draggingSource] || 0 == (mask & NSDragOperationGeneric)) {

        while (result == NSDragOperationNone && (type = [enumerator nextObject])) {

            // In any case, we accept the drag only if the pasteboard contains one of our desired types

            if ([availableTypes containsObject:type]) {

                // We always place the drop after the last existing row

                [tv setDropRow:[tv numberOfRows] dropOperation:NSTableViewDropAbove];

                result = NSDragOperationCopy;

            }

        }

    }

    return result;

}

- (BOOL)tableView:(NSTableView *)tv acceptDrop:(id <NSDraggingInfo>)info row:(NSInteger)row dropOperation:(NSTableViewDropOperation)op {

    // This method will be called when a drag in is finally dropped on our table view

    return [_document readSelectionFromPasteboard:[info draggingPasteboard]];

}

@end