/*

     File: ATDynamicTableView.m

 Abstract: An NSTableView subclass that adds delegate extensions for lazily batch loading cell contents, sub-view support, and multi-valued properties.

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*/

#import "ATDynamicTableView.h"

@interface ATDynamicTableView(ATPrivate)

- (void)_removeCachedViewForRow:(NSInteger)row;

- (void)_removeCachedViewsInIndexSet:(NSIndexSet *)rowIndexes;

@end

@implementation ATDynamicTableView

@dynamic delegate;

- (id)initWithCoder:(NSCoder *)coder {

    self = [super initWithCoder:coder];

    _dynEditingRow = -1;

    _dynEditingColumn = -1;

    return self;

}

- (void)dealloc {

    [_viewsInVisibleRows release];

    _viewsInVisibleRows = nil;

    [super dealloc];

}

- (void)_ensureVisibleRowsIsCreated {

    if (_viewsInVisibleRows == nil) {

        _viewsInVisibleRows = [NSMutableDictionary new];

    }

}

- (void)viewWillDraw {

    // We have to call super first in case the NSTableView does some layout in -viewWillDraw

    [super viewWillDraw];

    // Calculate the new visible rows and let the delegate do any extra work it wants to

    NSRange newVisibleRows = [self rowsInRect:self.visibleRect];

    BOOL visibleRowsNeedsUpdate = !NSEqualRanges(newVisibleRows, _visibleRows);

    NSRange oldVisibleRows = _visibleRows;

    if (visibleRowsNeedsUpdate) {

        _visibleRows = newVisibleRows;

        // Give the delegate a chance to do any pre-loading or special work that it wants to do

        if ([[self delegate] respondsToSelector:@selector(dynamicTableView:changedVisibleRowsFromRange:toRange:)]) {

            [[self delegate] dynamicTableView:self changedVisibleRowsFromRange:oldVisibleRows toRange:newVisibleRows];

        }

        // We always have to update our views if the visible area changed

        _viewsNeedUpdate = YES;

    }

    if (_viewsNeedUpdate) {

        _viewsNeedUpdate = NO;

        // Update any views that the delegate wants to give us

        if ([[self delegate] respondsToSelector:@selector(dynamicTableView:viewForRow:)]) {

            if (visibleRowsNeedsUpdate) {

                // First, remove any views that are no longer before our new visible rows

                NSMutableIndexSet *rowIndexesToRemove = [NSMutableIndexSet indexSetWithIndexesInRange:oldVisibleRows];

                // Remove any rows from the set that are STILL visible; we want a resulting

                // index set that has the views which are no longer on screen.

                [rowIndexesToRemove removeIndexesInRange:newVisibleRows];

                // Remove those views which are no longer visible

                [self _removeCachedViewsInIndexSet:rowIndexesToRemove];

            }

            [self _ensureVisibleRowsIsCreated];

            // Finally, update and add in any new views given to us by the delegate.

            // Use [NSNull null] for things that don't have a view at a particular row

            for (NSInteger row = _visibleRows.location; row < NSMaxRange(_visibleRows); row++) {

                NSNumber *key = [NSNumber numberWithInteger:row];

                id view = [_viewsInVisibleRows objectForKey:key];

                if (view == nil) {

                    // We don't already have a view at that row

                    view = [[self delegate] dynamicTableView:self viewForRow:row];

                    if (view != nil) {

                        [self addSubview:view];

                    } else {

                        // Use null as a place holder so we don't call the delegate again

                        // until the row is relaoded

                        view = [NSNull null]; 

                    }

                    [_viewsInVisibleRows setObject:view forKey:key];

                }

            }

        }

    }

}

- (void)_removeCachedViewForRow:(NSInteger)row {

    _viewsNeedUpdate = YES;

    if (_viewsInVisibleRows != nil) {

        NSNumber *key = [NSNumber numberWithInteger:row];

        id view = [_viewsInVisibleRows objectForKey:key];

        if (view != nil) {

            if (view != [NSNull null]) {

                [view removeFromSuperview];

            }

            [_viewsInVisibleRows removeObjectForKey:key];

        }

    }

}

- (void)_removeCachedViewsInIndexSet:(NSIndexSet *)rowIndexes {

    if (rowIndexes != nil) {

        for (NSInteger row = [rowIndexes firstIndex]; row != NSNotFound; row = [rowIndexes indexGreaterThanIndex:row]) {

            [self _removeCachedViewForRow:row];

        }

    }                 

}

- (void)_removeAllCachedViews {

    if (_viewsInVisibleRows != nil) {

        for (id view in [_viewsInVisibleRows allValues]) {

            [view removeFromSuperview];

        }

        [_viewsInVisibleRows release];

        _viewsInVisibleRows = nil;

    }

}             

// Reset our visible row cache when we reload things

- (void)reloadData {

    [self _removeAllCachedViews];

    _visibleRows = NSMakeRange(NSNotFound, 0);

    [super reloadData];

}

- (void)noteHeightOfRowsWithIndexesChanged:(NSIndexSet *)indexSet {

    // We replace all cached views, as their offsets may change

    [self _removeAllCachedViews];

    _visibleRows = NSMakeRange(NSNotFound, 0);

    [super noteHeightOfRowsWithIndexesChanged:indexSet];

}

- (void)reloadDataForRowIndexes:(NSIndexSet *)rowIndexes columnIndexes:(NSIndexSet *)columnIndexes {

    [self _removeCachedViewsInIndexSet:rowIndexes];

    [super reloadDataForRowIndexes:rowIndexes columnIndexes:columnIndexes];

}

- (void)setDelegate:(id <ATDynamicTableViewDelegate>)delegate {

    [super setDelegate:delegate];

}

- (id <ATDynamicTableViewDelegate>)delegate {

    return (id <ATDynamicTableViewDelegate>)[super delegate];

}

// We override the edited column and row and return our cell that is currently being edited by a seperate editor

- (NSInteger)editedColumn {

    if (_dynEditingColumn != -1) {

        return _dynEditingColumn;

    } else {

        return [super editedColumn];

    }

}

- (NSInteger)editedRow {

    if (_dynEditingRow != -1) {

        return _dynEditingRow;

    } else {

        return [super editedRow];

    }

}

- (NSCell *)preparedCellAtColumn:(NSInteger)column row:(NSInteger)row {

    if (_dynEditingRow == row && _dynEditingColumn == column) {

        return [[_dynEditingCell retain] autorelease];

    } else {

        return [super preparedCellAtColumn:column row:row];

    }

}

// The cell editor may want to dynamically update the cell for this control view

- (void)updateCell:(NSCell *)aCell {

    if (aCell == _dynEditingCell) {

        [self reloadDataForRowIndexes:[NSIndexSet indexSetWithIndex:_dynEditingRow] columnIndexes:[NSIndexSet indexSetWithIndex:_dynEditingColumn]];

    } else {

        [super updateCell:aCell];

    }

}

- (void)willStartEditingProperty:(NSString *)propertyName forCell:(NSCell *)cell {

    // Store off the row/column we are editing

    if (_editingCount == 0) {

        _dynEditingRow = [self clickedRow];

        _dynEditingColumn = [self clickedColumn];

        _dynEditingCell = [cell retain];

    }

    _editingCount++;

}

- (void)didEndEditingProperty:(NSString *)propertyName forCell:(NSCell *)cell successfully:(BOOL)success {

    _editingCount--;

    // Inform the delegate/datasource of the change!

    if (success && [[self delegate] respondsToSelector:@selector(dynamicTableView:setObjectValue:forTableColumn:row:property:)]) {

        id newValue = [cell valueForKey:propertyName];

        NSTableColumn *tableColumn = _dynEditingColumn != -1 ? [self.tableColumns objectAtIndex:_dynEditingColumn] : nil;

        [[self delegate] dynamicTableView:self setObjectValue:newValue forTableColumn:tableColumn row:_dynEditingRow property:propertyName];

    }

    if (_editingCount == 0) {

        _dynEditingRow = -1;

        _dynEditingColumn = -1;

        [_dynEditingCell release];

        _dynEditingCell = nil;

    }

}

@end