/*

File: BoardView.m

Abstract: NSView that hosts a game.

Version: 1.0

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*/

#import "BoardView.h"

#import "Bit.h"

#import "BitHolder.h"

#import "Game.h"

#import "QuartzUtils.h"

/**  WARNING: THIS CODE REQUIRES GARBAGE COLLECTION!

 **  This sample application uses Objective-C 2.0 garbage collection.

 **  Therefore, the source code in this file does NOT perform manual object memory management.

 **  If you reuse any of this code in a process that isn't garbage collected, you will need to

 **  add all necessary retain/release/autorelease calls, and implement -dealloc methods,

 **  otherwise unpleasant leakage will occur!

 **/

@implementation BoardView

@synthesize game=_game, gameboard=_gameboard;

- (void) startGameNamed: (NSString*)gameClassName

{

    if( _gameboard ) {

        [_gameboard removeFromSuperlayer];

        _gameboard = nil;

    }

    _gameboard = [[CALayer alloc] init];

    _gameboard.frame = [self gameBoardFrame];

    _gameboard.autoresizingMask = kCALayerWidthSizable | kCALayerHeightSizable;

    [self.layer addSublayer: _gameboard];

    Class gameClass = NSClassFromString(gameClassName);

    _game = [[gameClass alloc] initWithBoard: _gameboard];

}

- (CGRect) gameBoardFrame

{

    return self.layer.bounds;

}

- (void)resetCursorRects

{

    [super resetCursorRects];

    [self addCursorRect: self.bounds cursor: [NSCursor openHandCursor]];

}

- (IBAction) enterFullScreen: (id)sender

{

    if( self.isInFullScreenMode ) {

        [self exitFullScreenModeWithOptions: nil];

    } else {

        [self enterFullScreenMode: self.window.screen 

                      withOptions: nil];

    }

}

#pragma mark -

#pragma mark KEY EVENTS:

- (void) keyDown: (NSEvent*)ev

{

    if( self.isInFullScreenMode ) {

        if( [ev.charactersIgnoringModifiers hasPrefix: @"\033"] )       // Esc key

            [self enterFullScreen: self];

    }

}

#pragma mark -

#pragma mark HIT-TESTING:

// Hit-testing callbacks (to identify which layers caller is interested in):

typedef BOOL (*LayerMatchCallback)(CALayer*);

static BOOL layerIsBit( CALayer* layer )        {return [layer isKindOfClass: [Bit class]];}

static BOOL layerIsBitHolder( CALayer* layer )  {return [layer conformsToProtocol: @protocol(BitHolder)];}

static BOOL layerIsDropTarget( CALayer* layer ) {return [layer respondsToSelector: @selector(draggingEntered:)];}

/** Locates the layer at a given point in window coords.

    If the leaf layer doesn't pass the layer-match callback, the nearest ancestor that does is returned.

    If outOffset is provided, the point's position relative to the layer is stored into it. */

- (CALayer*) hitTestPoint: (NSPoint)locationInWindow

         forLayerMatching: (LayerMatchCallback)match

                   offset: (CGPoint*)outOffset

{

    CGPoint where = NSPointToCGPoint([self convertPoint: locationInWindow fromView: nil]);

    where = [_gameboard convertPoint: where fromLayer: self.layer];

    CALayer *layer = [_gameboard hitTest: where];

    while( layer ) {

        if( match(layer) ) {

            CGPoint bitPos = [self.layer convertPoint: layer.position 

                              fromLayer: layer.superlayer];

            if( outOffset )

                *outOffset = CGPointMake( bitPos.x-where.x, bitPos.y-where.y);

            return layer;

        } else

            layer = layer.superlayer;

    }

    return nil;

}

#pragma mark -

#pragma mark MOUSE CLICKS & DRAGS:

- (void) mouseDown: (NSEvent*)ev

{

    _dragStartPos = ev.locationInWindow;

    _dragBit = (Bit*) [self hitTestPoint: _dragStartPos

                        forLayerMatching: layerIsBit 

                                  offset: &_dragOffset];

    if( _dragBit ) {

        _dragMoved = NO;

        _dropTarget = nil;

        _oldHolder = _dragBit.holder;

        // Ask holder's and game's permission before dragging:

        if( _oldHolder )

            _dragBit = [_oldHolder canDragBit: _dragBit];

        if( _dragBit && ! [_game canBit: _dragBit moveFrom: _oldHolder] ) {

            [_oldHolder cancelDragBit: _dragBit];

            _dragBit = nil;

        }

        if( ! _dragBit ) {

            _oldHolder = nil;

            NSBeep();

            return;

        }

        // Start dragging:

        _oldSuperlayer = _dragBit.superlayer;

        _oldLayerIndex = [_oldSuperlayer.sublayers indexOfObjectIdenticalTo: _dragBit];

        _oldPos = _dragBit.position;

        ChangeSuperlayer(_dragBit, self.layer, self.layer.sublayers.count);

        _dragBit.pickedUp = YES;

        [[NSCursor closedHandCursor] push];

    } else

        NSBeep();

}

- (void) mouseDragged: (NSEvent*)ev

{

    if( _dragBit ) {

        // Get the mouse position, and see if we've moved 3 pixels since the mouseDown:

        NSPoint pos = ev.locationInWindow;

        if( fabs(pos.x-_dragStartPos.x)>=3 || fabs(pos.y-_dragStartPos.y)>=3 )

            _dragMoved = YES;

        // Move the _dragBit (without animation -- it's unnecessary and slows down responsiveness):

        NSPoint where = [self convertPoint: pos fromView: nil];

        where.x += _dragOffset.x;

        where.y += _dragOffset.y;

        CGPoint newPos = [_dragBit.superlayer convertPoint: NSPointToCGPoint(where) 

                                                 fromLayer: self.layer];

        [CATransaction flush];

        [CATransaction begin];

        [CATransaction setValue:(id)kCFBooleanTrue

                         forKey:kCATransactionDisableActions];

        _dragBit.position = newPos;

        [CATransaction commit];

        // Find what it's over:

        id<BitHolder> target = (id<BitHolder>) [self hitTestPoint: where

                                                 forLayerMatching: layerIsBitHolder

                                                           offset: NULL];

        if( target == _oldHolder )

            target = nil;

        if( target != _dropTarget ) {

            [_dropTarget willNotDropBit: _dragBit];

            _dropTarget.highlighted = NO;

            _dropTarget = nil;

        }

        if( target ) {

            CGPoint targetPos = [(CALayer*)target convertPoint: _dragBit.position

                                                     fromLayer: _dragBit.superlayer];

            if( [target canDropBit: _dragBit atPoint: targetPos]

               && [_game canBit: _dragBit moveFrom: _oldHolder to: target] ) {

                _dropTarget = target;

                _dropTarget.highlighted = YES;

            }

        }

    }

}

- (void) mouseUp: (NSEvent*)ev

{

    if( _dragBit ) {

        if( _dragMoved ) {

            // Update the drag tracking to the final mouse position:

            [self mouseDragged: ev];

            _dropTarget.highlighted = NO;

            _dragBit.pickedUp = NO;

            // Is the move legal?

            if( _dropTarget && [_dropTarget dropBit: _dragBit

                                            atPoint: [(CALayer*)_dropTarget convertPoint: _dragBit.position 

                                                                            fromLayer: _dragBit.superlayer]] ) {

                // Yes, notify the interested parties:

                [_oldHolder draggedBit: _dragBit to: _dropTarget];

                [_game bit: _dragBit movedFrom: _oldHolder to: _dropTarget];

            } else {

                // Nope, cancel:

                [_dropTarget willNotDropBit: _dragBit];

                ChangeSuperlayer(_dragBit, _oldSuperlayer, _oldLayerIndex);

                _dragBit.position = _oldPos;

                [_oldHolder cancelDragBit: _dragBit];

            }

        } else {

            // Just a click, without a drag:

            _dropTarget.highlighted = NO;

            _dragBit.pickedUp = NO;

            ChangeSuperlayer(_dragBit, _oldSuperlayer, _oldLayerIndex);

            [_oldHolder cancelDragBit: _dragBit];

            if( ! [_game clickedBit: _dragBit] )

                NSBeep();

        }

        _dropTarget = nil;

        _dragBit = nil;

        [NSCursor pop];

    }

}

#pragma mark -

#pragma mark INCOMING DRAGS:

// subroutine to call the target

static int tell( id target, SEL selector, id arg, int defaultValue )

{

    if( target && [target respondsToSelector: selector] )

        return (ssize_t) [target performSelector: selector withObject: arg];

    else

        return defaultValue;

}

- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender

{

    _viewDropTarget = [self hitTestPoint: [sender draggingLocation]

                        forLayerMatching: layerIsDropTarget

                                  offset: NULL];

    _viewDropOp = _viewDropTarget ?[_viewDropTarget draggingEntered: sender] :NSDragOperationNone;

    return _viewDropOp;

}

- (NSDragOperation)draggingUpdated:(id <NSDraggingInfo>)sender

{

    CALayer *target = [self hitTestPoint: [sender draggingLocation]

                        forLayerMatching: layerIsDropTarget 

                                  offset: NULL];

    if( target == _viewDropTarget ) {

        if( _viewDropTarget )

            _viewDropOp = tell(_viewDropTarget,@selector(draggingUpdated:),sender,_viewDropOp);

    } else {

        tell(_viewDropTarget,@selector(draggingExited:),sender,0);

        _viewDropTarget = target;

        if( _viewDropTarget )

            _viewDropOp = [_viewDropTarget draggingEntered: sender];

        else

            _viewDropOp = NSDragOperationNone;

    }

    return _viewDropOp;

}

- (BOOL)wantsPeriodicDraggingUpdates

{

    return (_viewDropTarget!=nil);

}

- (void)draggingExited:(id <NSDraggingInfo>)sender

{

    tell(_viewDropTarget,@selector(draggingExited:),sender,0);

    _viewDropTarget = nil;

}

- (BOOL)prepareForDragOperation:(id <NSDraggingInfo>)sender

{

    return tell(_viewDropTarget,@selector(prepareForDragOperation:),sender,YES);

}

- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender

{

    return [_viewDropTarget performDragOperation: sender];

}

- (void)concludeDragOperation:(id <NSDraggingInfo>)sender

{

    tell(_viewDropTarget,@selector(concludeDragOperation:),sender,0);

}

- (void)draggingEnded:(id <NSDraggingInfo>)sender

{

    tell(_viewDropTarget,@selector(draggingEnded:),sender,0);

}

@end