/*

     File: DMKArrayController.m

 Abstract: An array controller subclass to manage a collection of text snippets, including support for drag and drop.

  Version: 1.1

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 */

#import "DMKArrayController.h"

#import "EditController.h"

#import "MyDocument.h"

#import "Step.h"

NSString *MovedRowsUTI = @"com.yourcompany.demomonkey.movedrows";

@implementation DMKArrayController

@synthesize tableView, windowController;

#pragma mark -

#pragma mark Pasteboard / drag and drop support

- (void)awakeFromNib {

    // Register the table view for drag and drop.

    [tableView registerForDraggedTypes:[NSArray arrayWithObjects:StepUTI, MovedRowsUTI, NSStringPboardType, nil]];

    [tableView setAllowsMultipleSelection:YES];

    [tableView setDraggingSourceOperationMask:NSDragOperationCopy forLocal:NO];

}

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

    /*

     Take ownership of the pasteboard, then:

     * Write the currently-selected steps directly;

     * Archive the selection index set and write the archive to the pasteboard as the data for the moved rows type.  The index set is used in tableView:acceptDrop:row:dropOperation: if there is a reorder operation within a table view.

     */

    [pboard clearContents];

    // Write the current steps.

    [pboard writeObjects:[[self arrangedObjects] objectsAtIndexes:rowIndexes]];

    // Add rows array for a local move.

    [pboard addTypes:[NSArray arrayWithObject:MovedRowsUTI] owner:self];        

    NSData *rowIndexesData = [NSArchiver archivedDataWithRootObject:rowIndexes];

    [pboard setData:rowIndexesData forType:MovedRowsUTI];        

    return YES;

}

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

    NSDragOperation dragOp = NSDragOperationCopy;

    // If drag source is self, it's a move.

    if ([info draggingSource] == tableView) {

        dragOp =  NSDragOperationMove;

    }

    // Put the object at, not over, the current row (contrast NSTableViewDropOn).

    if ([[self arrangedObjects] count] > 0) {

        [aTableView setDropRow:row dropOperation:NSTableViewDropAbove];

    }

    return dragOp;

}

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

    if (row < 0) {

        row = 0;

    }

    /*

     If the dragging source is our table view, look for the moved rows type for a reorder operation.

     */

    if ([info draggingSource] == tableView) {

        NSData *rowsData = [[info draggingPasteboard] dataForType:MovedRowsUTI];

        NSIndexSet  *indexSet = [NSUnarchiver unarchiveObjectWithData:rowsData];        

        [self moveObjectsInArrangedObjectsFromIndexes:indexSet toIndex:row];

        /*

         Set the selected rows to those that were just moved.  Work out what moved where to determine proper selection.

         */

        NSInteger rowsAbove = [self rowsAboveRow:row inIndexSet:indexSet];

        NSRange range = NSMakeRange(row - rowsAbove, [indexSet count]);

        indexSet = [NSIndexSet indexSetWithIndexesInRange:range];

        [self setSelectionIndexes:indexSet];

        return YES;

    }

    /*

     If the dragging source is something other than our table view, create new steps from whatever's on the pasteboard and add them.

     */

    NSDictionary *options = [NSDictionary dictionary];

    NSArray *newSteps = [[info draggingPasteboard] readObjectsForClasses:[NSArray arrayWithObject:[Step class]] options:options];

    if (newSteps == nil) {

        return NO;

    }

    NSRange insertionRange = NSMakeRange(row, [newSteps count]);

    NSIndexSet *insertionIndexes = [NSIndexSet indexSetWithIndexesInRange:insertionRange];

    [self insertObjects:newSteps atArrangedObjectIndexes:insertionIndexes];

    return YES;

}

#pragma mark -

#pragma mark New objects

- (id)newObject {

    // Configure a new object.

    Step *newObject = [super newObject];

    NSUInteger row = [[self arrangedObjects] count];

    newObject.tableSummary = [NSString stringWithFormat:@"Step %d", (row +1)];

    newObject.undoManager = [[windowController document] undoManager];

    return newObject;

}

- (void)add:sender {

    // Add a new object, then select its row.

    Step *newObject = [super newObject];

    NSUInteger row = [[self arrangedObjects] count];

    [self insertObject:newObject atArrangedObjectIndex:row];

    [tableView selectRowIndexes:[NSIndexSet indexSetWithIndex:row] byExtendingSelection:NO];

    [tableView editColumn:0 row:row withEvent:nil select:YES];

    [newObject release];

}

#pragma mark -

#pragma mark Reorder operation

-(void) moveObjectsInArrangedObjectsFromIndexes:(NSIndexSet*)indexSet toIndex:(NSUInteger)insertIndex {

    NSArray *objects = [self arrangedObjects];

    NSInteger idx = [indexSet lastIndex];

    NSInteger aboveInsertIndexCount = 0;

    id object = nil;

    NSInteger removeIndex;

    while (NSNotFound != idx) {

        if (idx >= insertIndex) {

            removeIndex = idx + aboveInsertIndexCount;

            aboveInsertIndexCount += 1;

        }

        else {

            removeIndex = idx;

            insertIndex -= 1;

        }

        object = [[objects objectAtIndex:removeIndex] retain];

        [self removeObjectAtArrangedObjectIndex:removeIndex];

        [self insertObject:object atArrangedObjectIndex:insertIndex];

        [object release];

        idx = [indexSet indexLessThanIndex:idx];

    }

}

- (NSInteger)rowsAboveRow:(NSInteger)row inIndexSet:(NSIndexSet *)indexSet {

    NSUInteger currentIndex = [indexSet firstIndex];

    NSInteger i = 0;

    while (currentIndex != NSNotFound) {

        if (currentIndex < row) { i++; }

        currentIndex = [indexSet indexGreaterThanIndex:currentIndex];

    }

    return i;

}

@end