/*

 File: TrackableOutlineView.m

 Abstract: The TrackableOutlineView provides an implementation of updateTrackingAreas

 that automatically delegates to cells which implement the informal

 CellTrackingRect protocol.

 Version: 1.0

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 */ 

#import "TrackableOutlineView.h"

#import <AppKit/NSTrackingArea.h>

#import "CellTrackingRect.h" 

@implementation TrackableOutlineView

- (id)init {

    self = [super init];

    if (self) {

        iMouseRow = -1;

        iMouseCol = -1;

    }

    return self;

}

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

    self = [super initWithCoder:coder];

    if (self) {

        iMouseRow = -1;

        iMouseCol = -1;

    }

    return self;

}

- (void)dealloc {

    [iMouseCell release];

    [super dealloc];

}

// Tracking rect support

- (void)updateTrackingAreas {

    for (NSTrackingArea *area in [self trackingAreas]) {

        // We have to uniquely identify our own tracking areas

        if (([area owner] == self) && ([[area userInfo] objectForKey:@"Row"] != nil)) {

            [self removeTrackingArea:area];

        }

    }

     // Find the visible cells that have a non-empty tracking rect and add rects for each of them

    NSRange visibleRows = [self rowsInRect:[self visibleRect]];

    NSIndexSet *visibleColIndexes = [self columnIndexesInRect:[self visibleRect]];

    NSPoint mouseLocation = [self convertPoint:[[self window] convertScreenToBase:[NSEvent mouseLocation]] fromView:nil];

    for (NSInteger row = visibleRows.location; row < visibleRows.location + visibleRows.length; row++ ) {

        // If it is a "full width" cell, we don't have to go through the rows

        NSCell *fullWidthCell = [self preparedCellAtColumn:-1 row:row];

        if (fullWidthCell) {

            if ([fullWidthCell respondsToSelector:@selector(addTrackingAreasForView:inRect:withUserInfo:mouseLocation:)]) {

                NSInteger col = -1;

                NSDictionary *userInfo = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInteger:col], @"Col", [NSNumber numberWithInteger:row], @"Row", nil];

                [fullWidthCell addTrackingAreasForView:self inRect:[self frameOfCellAtColumn:col row:row] withUserInfo:userInfo mouseLocation:mouseLocation];

            }

        } else {

            for (NSInteger col = [visibleColIndexes firstIndex]; col != NSNotFound; col = [visibleColIndexes indexGreaterThanIndex:col]) {

                NSCell *cell = [self preparedCellAtColumn:col row:row];

                if ([cell respondsToSelector:@selector(addTrackingAreasForView:inRect:withUserInfo:mouseLocation:)]) {

                    NSDictionary *userInfo = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInteger:col], @"Col", [NSNumber numberWithInteger:row], @"Row", nil];

                    [cell addTrackingAreasForView:self inRect:[self frameOfCellAtColumn:col row:row] withUserInfo:userInfo mouseLocation:mouseLocation];

                }

            }

        }

    }

}

- (void)mouseEntered:(NSEvent *)event {

    // Delegate this to the appropriate cell. In order to allow the cell to maintain state, we copy it and use the copy until the mouse is moved outside of the cell.

    NSDictionary *userInfo = [event userData];

    NSNumber *row = [userInfo valueForKey:@"Row"];

    NSNumber *col = [userInfo valueForKey:@"Col"];

    if (row && col) {

        NSInteger rowVal = [row integerValue]; 

        NSInteger colVal = [col integerValue];

        NSCell *cell = [self preparedCellAtColumn:colVal row:rowVal];

        // Only set the mouseCell properties AFTER calling preparedCellAtColumn:row:.

        if (iMouseCell != cell) {

            [iMouseCell release];

            // Store off the col/row

            iMouseCol = colVal;

            iMouseRow = rowVal;

            // Store a COPY of the cell for use when tracking in an area

            iMouseCell = [cell copy];

            [iMouseCell setControlView:self];

            [iMouseCell mouseEntered:event];

        }

    }

}

- (void)mouseExited:(NSEvent *)event {

    NSDictionary *userInfo = [event userData];

    NSNumber *row = [userInfo valueForKey:@"Row"];

    NSNumber *col = [userInfo valueForKey:@"Col"];

    if (row && col) {

        NSCell *cell = [self preparedCellAtColumn:[col integerValue] row:[row integerValue]];

        [cell setControlView:self];

        [cell mouseExited:event];

        // We are now done with the copied cell

        [iMouseCell release];

        iMouseCell = nil;

        iMouseCol = -1;

        iMouseRow = -1;

    }

}

/* Since NSTableView/NSOutineView uses the same cell to "stamp" out each row, we need to send the mouseEntered/mouseExited events each time it is drawn. The easy hook for this is the preparedCell method. 

*/

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

    // We check if the selectedCell is nil or not -- the selectedCell is a cell that is currently being edited or tracked. We don't want to return our override if we are in that state.

    if ([self selectedCell] == nil && (row == iMouseRow) && (column == iMouseCol)) {

        return iMouseCell;

    } else {

        return [super preparedCellAtColumn:column row:row];

    }

}

/* In order for the cell to properly update itself with an "updateCell:" call, we must handle the "mouseCell" as a special case

*/

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

    if (aCell == iMouseCell) {

        [self setNeedsDisplayInRect:[self frameOfCellAtColumn:iMouseCol row:iMouseRow]];

    } else {

        [super updateCell:aCell];

    }

}

@end