/*

File: Grid.h

Abstract: Abstract superclass of regular geometric grids of GridCells that Bits can be placed on.

Version: 1.0

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*/

#import "BitHolder.h"

@class GridCell;

/** Abstract superclass of regular geometric grids of GridCells that Bits can be placed on. */

@interface Grid : CALayer

{

    unsigned _nRows, _nColumns;                         

    CGSize _spacing;                                    

    Class _cellClass;                                   

    CGColorRef _cellColor, _lineColor;                  

    BOOL _usesDiagonals, _allowsMoves, _allowsCaptures;

    NSMutableArray *_cells;                             // Really a 2D array, in row-major order.

}

/** Initializes a new Grid with the given dimensions and cell size, and position in superview.

    Note that a new Grid has no cells! Either call -addAllCells, or -addCellAtRow:column:. */

- (id) initWithRows: (unsigned)nRows columns: (unsigned)nColumns

            spacing: (CGSize)spacing

           position: (CGPoint)pos;

/** Initializes a new Grid with the given dimensions and frame in superview.

    The cell size will be computed by dividing frame size by dimensions.

    Note that a new Grid has no cells! Either call -addAllCells, or -addCellAtRow:column:. */

- (id) initWithRows: (unsigned)nRows columns: (unsigned)nColumns

              frame: (CGRect)frame;

@property Class cellClass;                      // What kind of GridCells to create

@property (readonly) unsigned rows, columns;    // Dimensions of the grid

@property (readonly) CGSize spacing;            // x,y spacing of GridCells

@property CGColorRef cellColor, lineColor;      // Cell background color, line color (or nil)

@property BOOL usesDiagonals;                   // Affects GridCell.neighbors, for rect grids

@property BOOL allowsMoves, allowsCaptures;     // Can pieces be moved, and can they land on others?

/** Returns the GridCell at the given coordinates, or nil if there is no cell there.

    It's OK to call this with off-the-board coordinates; it will just return nil.*/

- (GridCell*) cellAtRow: (unsigned)row column: (unsigned)col;

/** Adds cells at all coordinates, creating a complete grid. */

- (void) addAllCells;

/** Adds a GridCell at the given coordinates. */

- (GridCell*) addCellAtRow: (unsigned)row column: (unsigned)col;

/** Removes a particular cell, leaving a blank space. */

- (void) removeCellAtRow: (unsigned)row column: (unsigned)col;

// protected:

- (GridCell*) createCellAtRow: (unsigned)row column: (unsigned)col 

               suggestedFrame: (CGRect)frame;

@end

/** Abstract superclass of a single cell in a grid. */

@interface GridCell : BitHolder

{

    Grid *_grid;

    unsigned _row, _column;

}

- (id) initWithGrid: (Grid*)grid 

                row: (unsigned)row column: (unsigned)col

              frame: (CGRect)frame;

@property (readonly) Grid* grid;

@property (readonly) unsigned row, column;

@property (readonly) NSArray* neighbors;        // Dependent on grid.usesDiagonals

/** Returns YES if 'forward' is north (increasing row#) for the current player */

@property (readonly) BOOL fwdIsN;

/* Go-style group detection. Returns the set of contiguous GridCells that have pieces of the same

   owner as this one, and optionally a count of the number of "liberties", or adjacent empty cells. */

- (NSSet*) getGroup: (int*)outLiberties;

// protected:

- (void) drawInParentContext: (CGContextRef)ctx fill: (BOOL)fill;

@end

/** A rectangular grid of squares. */

@interface RectGrid : Grid

{

    CGColorRef _altCellColor;

}

/** If non-nil, alternate cells will be drawn with this background color, in a checkerboard pattern.

    The precise rule is that cells whose row+column is odd use the altCellColor.*/

@property CGColorRef altCellColor;

@end

/* A square in a RectGrid */

@interface Square : GridCell

@property (readonly) Square *nw, *n, *ne, *e, *se, *s, *sw, *w;    // Absolute directions (n = increasing row#)

@property (readonly) Square *fl, *f, *fr, *r, *br, *b, *bl, *l;    // Relative to player (upside-down for player 2)

@end

/* Substitute this for Square in a RectGrid's cellClass to draw the lines through the centers

   of the squares, so the pieces sit on the intersections, as in a Go board. */

@interface GoSquare : Square

{

    BOOL _dotted;

}

/** Set to YES to put a dot at the intersection, as in the handicap points of a Go board. */

@property BOOL dotted;

@end