File content as of revision 11:43c89579ac52:

#include "mbed.h"
#include "uLCD_4DGL.h"
#include <vector>

uLCD_4DGL uLCD(p28,p27,p30); // serial tx, serial rx, reset pin;

enum Piece {e, wK, bK, wQ, bQ, wR, bR, wB, bB, wN, bN, w, b};
std::vector<Piece> whitePieces;
std::vector<Piece> blackPieces;

enum GameState {whiteSelecting, whitePickedUp, whiteAI, blackSelecting, blackPickedUp, blackAI};

struct pixelCoord {
    uint8_t x;
    uint8_t y;
};

struct boardPos {
    uint8_t row;
    uint8_t column;

    bool operator==(const boardPos &other) const
    {
        return row == other.row && column == other.column;
    }
};

class Nav_Switch
{
public:
    Nav_Switch(PinName up,PinName down,PinName left,PinName right,PinName fire);
    int read();
//boolean functions to test each switch
    bool up();
    bool down();
    bool left();
    bool right();
    bool fire();
//automatic read on RHS
    operator int ();
//index to any switch array style
    bool operator[](int index) {
        return _pins[index];
    };
private:
    BusIn _pins;

};
Nav_Switch::Nav_Switch (PinName up,PinName down,PinName left,PinName right,PinName fire):
    _pins(up, down, left, right, fire)
{
    _pins.mode(PullUp); //needed if pullups not on board or a bare nav switch is used - delete otherwise
    wait(0.001); //delays just a bit for pullups to pull inputs high
}
inline bool Nav_Switch::up()
{
    return !(_pins[0]);
}
inline bool Nav_Switch::down()
{
    return !(_pins[1]);
}
inline bool Nav_Switch::left()
{
    return !(_pins[2]);
}
inline bool Nav_Switch::right()
{
    return !(_pins[3]);
}
inline bool Nav_Switch::fire()
{
    return !(_pins[4]);
}
inline int Nav_Switch::read()
{
    return _pins.read();
}
inline Nav_Switch::operator int ()
{
    return _pins.read();
}

class BoardState
{
private:
    Piece array[64];
public:
    // calculates the advantage difference for the board state
    float calculateBoardState()
    {
        return 0.0;
    }

    // returns the piece at a given location
    Piece getPiece(int row, int column)
    {
        return array[column + 8 * row];
    }

    // puts a piece at a given location
    void placePiece(Piece piece, int row, int column)
    {
        array[column + 8 * row] = piece;
    }

    /*  removes a piece from the set position of the board
        returns the bit representation of the piece
    */
    Piece removePiece(int row, int column)
    {
        Piece removedPiece = array[column + 8 * row];
        array[column + 8 * row] = e;
        return removedPiece;
    }

    /*  moves a piece from one position to another
        returns the captured piece
    */
    Piece movePiece(int startRow, int startColumn, int endRow, int endColumn)
    {
        Piece movingPiece = removePiece(startRow, startColumn);
        Piece capturedPiece = removePiece(endRow, endColumn);
        placePiece(movingPiece, endRow, endColumn);
        return capturedPiece;
    }

    // generates a list of possible moves for a piece
    // returns moves
    std::vector<boardPos> getMoves(boardPos pos)
    {
        return getMoves(pos.row, pos.column);
    }
    std::vector<boardPos> getMoves(int row, int column)
    {
        std::vector<boardPos> moves;
        std::vector<boardPos> lineMoves;
        Piece movingPiece = getPiece(row, column);
        uint8_t rowIndex;
        uint8_t columnIndex;
        bool isWhite;
        switch(movingPiece) {
            case wK:
            case bK:
                isWhite = movingPiece == wK;
                if (validMove(isWhite, row + 1, column)) {
                    moves.push_back((boardPos) {
                        row + 1, column
                    });
                }
                if (validMove(isWhite, row, column + 1)) {
                    moves.push_back((boardPos) {
                        row, column + 1
                    });
                }
                if (validMove(isWhite, row - 1, column)) {
                    moves.push_back((boardPos) {
                        row - 1, column
                    });
                }
                if (validMove(isWhite, row, column - 1)) {
                    moves.push_back((boardPos) {
                        row, column - 1
                    });
                }
                if (validMove(isWhite, row + 1, column + 1)) {
                    moves.push_back((boardPos) {
                        row + 1, column + 1
                    });
                }
                if (validMove(isWhite, row - 1, column + 1)) {
                    moves.push_back((boardPos) {
                        row - 1, column + 1
                    });
                }
                if (validMove(isWhite, row - 1, column - 1)) {
                    moves.push_back((boardPos) {
                        row - 1, column - 1
                    });
                }
                if (validMove(isWhite, row + 1, column - 1)) {
                    moves.push_back((boardPos) {
                        row + 1, column - 1
                    });
                }
                break;
            case wQ:
            case bQ:
                isWhite = movingPiece == wQ;
                rowIndex = row + 1;
                columnIndex = column + 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex++;
                    columnIndex++;
                }
                rowIndex = row - 1;
                columnIndex = column + 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex--;
                    columnIndex++;
                }
                rowIndex = row + 1;
                columnIndex = column - 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex++;
                    columnIndex--;
                }
                rowIndex = row - 1;
                columnIndex = column - 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex--;
                    columnIndex--;
                }
                rowIndex = row + 1;
                columnIndex = column;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex++;
                }
                rowIndex = row - 1;
                columnIndex = column;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex--;
                }
                rowIndex = row;
                columnIndex = column + 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    columnIndex++;
                }
                rowIndex = row;
                columnIndex = column - 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    columnIndex--;
                }
                break;
            case wB:
            case bB:
                isWhite = movingPiece == wB;
                rowIndex = row + 1;
                columnIndex = column + 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex++;
                    columnIndex++;
                }
                rowIndex = row - 1;
                columnIndex = column + 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex--;
                    columnIndex++;
                }
                rowIndex = row + 1;
                columnIndex = column - 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex++;
                    columnIndex--;
                }
                rowIndex = row - 1;
                columnIndex = column - 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex--;
                    columnIndex--;
                }
                break;
            case wN:
            case bN:
                isWhite = movingPiece == wN;
                if (validMove(isWhite, row + 2, column + 1)) {
                    moves.push_back((boardPos) {
                        row + 2, column + 1
                    });
                }
                if (validMove(isWhite, row + 2, column - 1)) {
                    moves.push_back((boardPos) {
                        row + 2, column - 1
                    });
                }
                if (validMove(isWhite, row - 2, column - 1)) {
                    moves.push_back((boardPos) {
                        row - 2, column - 1
                    });
                }
                if (validMove(isWhite, row - 2, column + 1)) {
                    moves.push_back((boardPos) {
                        row - 2, column + 1
                    });
                }
                if (validMove(isWhite, row + 1, column + 2)) {
                    moves.push_back((boardPos) {
                        row + 1, column + 2
                    });
                }
                if (validMove(isWhite, row - 1, column + 2)) {
                    moves.push_back((boardPos) {
                        row - 1, column + 2
                    });
                }
                if (validMove(isWhite, row - 1, column - 2)) {
                    moves.push_back((boardPos) {
                        row - 1, column - 2
                    });
                }
                if (validMove(isWhite, row + 1, column - 2)) {
                    moves.push_back((boardPos) {
                        row + 1, column - 2
                    });
                }
                break;
            case wR:
            case bR:
                isWhite = movingPiece == wR;
                rowIndex = row + 1;
                columnIndex = column;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex++;
                }
                rowIndex = row - 1;
                columnIndex = column;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    rowIndex--;
                }
                rowIndex = row;
                columnIndex = column + 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    columnIndex++;
                }
                rowIndex = row;
                columnIndex = column - 1;
                while (validMove(isWhite, rowIndex, columnIndex)) {
                    moves.push_back((boardPos) {
                        rowIndex, columnIndex
                    });
                    if (getPiece(rowIndex, columnIndex) != e) {
                        break;
                    }
                    columnIndex--;
                }
                break;
            case w:
            case b:
                isWhite = movingPiece == w;
                int rowChange = isWhite ? 1 : -1;
                if (validMove(isWhite, row + rowChange, column) && getPiece(row + rowChange, column) == e) {
                    moves.push_back((boardPos) {
                        row + rowChange, column
                    });
                    // The case for pawns moving two squares at the start
                    if (((isWhite && row == 1) || (!isWhite && row == 6)) && validMove(isWhite, row + rowChange + rowChange, column) && getPiece(row + rowChange + rowChange, column) == e) {
                        moves.push_back((boardPos) {
                            row + rowChange + rowChange, column
                        });
                    }
                }
                if (validMove(isWhite, row + rowChange, column + 1) && getPiece(row + rowChange, column + 1) != e) {
                    moves.push_back((boardPos) {
                        row + rowChange, column + 1
                    });
                }
                if (validMove(isWhite, row + rowChange, column - 1) && getPiece(row + rowChange, column - 1) != e) {
                    moves.push_back((boardPos) {
                        row + rowChange, column - 1
                    });
                }
                break;
            default:
                break;
        }
        return moves;
    }

    // returns a vector of board positions that a piece can move in a line
    std::vector<boardPos> movesInLine(bool isMovingPieceWhite, int row, int column, int rowChange, int columnChange)
    {
        std::vector<boardPos> moves;
        for (int i = 1; ; i++) {
            // check if piece can move to location
            if (validMove(isMovingPieceWhite, row + i * rowChange, column + i * columnChange)) {
                moves.push_back((boardPos) {
                    row + i * rowChange, column + i * columnChange
                });
                // if piece is capturable, stop moving beyond it
                if (getPiece(row + i * rowChange, column + i * columnChange) != e) {
                    break;
                }
                // if unable to move, break out
            } else {
                break;
            }
        }
        return moves;
    }

    // returns if a piece can move to a given location
    bool validMove(bool isMovingPieceWhite, int row, int column)
    {
        if (row < 0 || row > 7 || column < 0 || column > 7) {
            return false;
        }
        Piece capturedPiece = getPiece(row, column);
        switch(capturedPiece) {
            case wK:
            case wQ:
            case wR:
            case wB:
            case wN:
            case w:
                return !isMovingPieceWhite;
            case bK:
            case bQ:
            case bR:
            case bB:
            case bN:
            case b:
                return isMovingPieceWhite;
            case e:
                return true;
        }
        return false;
    }
};

class GameBoard
{
private:
    BoardState boardState;
    static const int BOARD_DARK_COLOR = 0x769656;
    static const int BOARD_LIGHT_COLOR = 0xbaca44;
    static const int HOVER_COLOR = 0x0000ff;
    static const int SELECTED_COLOR = 0xff8800;
    static const int MOVE_COLOR = 0xff00ff;
    
    // gets the pixel coordinates of the top left of the square 
    static pixelCoord getTopLeftOfSquare(boardPos pos)  
    {   
        return getTopLeftOfSquare(pos.row, pos.column); 
    }   
    static pixelCoord getTopLeftOfSquare(int row, int column)   
    {   
        pixelCoord topLeft; 
        topLeft.x = 16 * column;    
        topLeft.y = 112 - 16 * row; 
        return topLeft; 
    }

    // piece sprites (12 x 12)  
    static void drawPawn(int row, int column, bool white, bool light)   
    {   
        int X = white ? 0xffffff : 0x000000;    
        int _ = light ? BOARD_LIGHT_COLOR : BOARD_DARK_COLOR;   
        int sprite[144] = {_, _, _, _, _, _, _, _, _, _, _, _,  
                           _, _, _, _, _, _, _, _, _, _, _, _,  
                           _, _, _, _, _, _, _, _, _, _, _, _,  
                           _, _, _, _, _, _, _, _, _, _, _, _,  
                           _, _, _, _, _, X, X, _, _, _, _, _,  
                           _, _, _, _, X, X, X, X, _, _, _, _,  
                           _, _, _, _, X, X, X, X, _, _, _, _,  
                           _, _, _, _, _, X, X, _, _, _, _, _,  
                           _, _, _, _, _, X, X, _, _, _, _, _,  
                           _, _, _, _, X, X, X, X, _, _, _, _,  
                           _, _, X, X, X, X, X, X, X, X, _, _,  
                           _, _, X, X, X, X, X, X, X, X, _, _   
                          };    
        pixelCoord tl = getTopLeftOfSquare(row, column);    
        uLCD.BLIT(tl.x + 2, tl.y + 2, 12, 12, sprite);  
    }   
    static void drawRook(int row, int column, bool white, bool light)   
    {   
        int X = white ? 0xffffff : 0x000000;    
        int _ = light ? BOARD_LIGHT_COLOR : BOARD_DARK_COLOR;   
        int sprite[144] = {X, X, _, X, X, _, _, X, X, _, X, X,  
                           X, X, _, X, X, _, _, X, X, _, X, X,  
                           X, X, X, X, X, X, X, X, X, X, X, X,  
                           X, X, X, X, X, X, X, X, X, X, X, X,  
                           _, X, X, X, _, X, X, _, X, X, X, _,  
                           _, X, X, X, _, X, X, _, X, X, X, _,  
                           _, _, X, X, _, X, X, _, X, X, _, _,  
                           _, _, X, X, _, X, X, _, X, X, _, _,  
                           _, _, X, X, _, X, X, _, X, X, _, _,  
                           _, X, X, X, X, X, X, X, X, X, X, _,  
                           X, X, X, X, X, X, X, X, X, X, X, X,  
                           X, X, X, X, X, X, X, X, X, X, X, X   
                          };    
        pixelCoord tl = getTopLeftOfSquare(row, column);    
        uLCD.BLIT(tl.x + 2, tl.y + 2, 12, 12, sprite);  
    }   
    static void drawKnight(int row, int column, bool white, bool light) 
    {   
        int X = white ? 0xffffff : 0x000000;    
        int _ = light ? BOARD_LIGHT_COLOR : BOARD_DARK_COLOR;   
        int sprite[144] = {_, _, _, _, _, _, _, _, _, _, _, _,  
                           _, _, _, _, _, X, X, _, X, X, _, _,  
                           _, _, _, _, _, X, X, _, X, X, _, _,  
                           _, _, _, X, X, X, X, X, X, _, _, _,  
                           _, _, X, X, X, X, X, _, X, _, _, _,  
                           _, _, X, X, X, X, X, X, X, _, _, _,  
                           _, _, _, _, _, X, X, X, X, _, _, _,  
                           _, _, _, _, X, X, X, X, X, _, _, _,  
                           _, _, _, X, X, X, X, X, X, X, _, _,  
                           _, _, X, X, X, X, X, X, X, X, _, _,  
                           _, X, X, X, X, X, X, X, X, X, X, _,  
                           _, X, X, X, X, X, X, X, X, X, X, _   
                          };    
        pixelCoord tl = getTopLeftOfSquare(row, column);    
        uLCD.BLIT(tl.x + 2, tl.y + 2, 12, 12, sprite);  
    }   
    static void drawBishop(int row, int column, bool white, bool light) 
    {   
        int X = white ? 0xffffff : 0x000000;    
        int _ = light ? BOARD_LIGHT_COLOR : BOARD_DARK_COLOR;   
        int sprite[144] = {_, _, _, _, _, X, X, _, _, _, _, _,  
                           _, _, _, _, X, X, X, _, _, _, _, _,  
                           _, _, _, X, X, X, _, _, X, _, _, _,  
                           _, _, _, X, X, _, _, X, X, _, _, _,  
                           _, _, _, X, X, X, X, X, X, _, _, _,  
                           _, _, _, _, X, X, X, X, _, _, _, _,  
                           _, _, _, _, _, X, X, _, _, _, _, _,  
                           _, _, _, _, X, X, X, X, _, _, _, _,  
                           _, _, _, X, X, X, X, X, X, _, _, _,  
                           _, _, _, X, X, X, X, X, X, _, _, _,  
                           _, _, X, X, X, X, X, X, X, X, _, _,  
                           _, _, X, X, X, X, X, X, X, X, _, _   
                          };    
        pixelCoord tl = getTopLeftOfSquare(row, column);    
        uLCD.BLIT(tl.x + 2, tl.y + 2, 12, 12, sprite);  
    }   
    static void drawQueen(int row, int column, bool white, bool light)  
    {   
        int X = white ? 0xffffff : 0x000000;    
        int _ = light ? BOARD_LIGHT_COLOR : BOARD_DARK_COLOR;   
        int sprite[144] = {_, _, _, _, _, X, X, _, _, _, _, _,  
                           _, _, X, _, _, X, X, _, _, X, _, _,  
                           X, _, X, X, _, X, X, _, X, X, _, X,  
                           X, _, X, X, _, X, X, _, X, X, _, X,  
                           X, _, X, X, _, X, X, _, X, X, _, X,  
                           X, X, X, X, X, X, X, X, X, X, X, X,  
                           X, X, X, X, X, X, X, X, X, X, X, X,  
                           X, X, _, X, X, X, X, X, X, _, X, X,  
                           X, X, X, X, _, X, X, _, X, X, X, X,  
                           _, X, X, X, X, X, X, X, X, X, X, _,  
                           _, _, X, X, X, X, X, X, X, X, _, _,  
                           _, X, X, X, X, X, X, X, X, X, X, _   
                          };    
        pixelCoord tl = getTopLeftOfSquare(row, column);    
        uLCD.BLIT(tl.x + 2, tl.y + 2, 12, 12, sprite);  
    }   
    static void drawKing(int row, int column, bool white, bool light)   
    {   
        int X = white ? 0xffffff : 0x000000;    
        int _ = light ? BOARD_LIGHT_COLOR : BOARD_DARK_COLOR;   
        int sprite[144] = {_, _, _, _, _, X, X, _, _, _, _, _,  
                           _, _, _, _, _, X, X, _, _, _, _, _,  
                           _, _, _, X, X, X, X, X, X, _, _, _,  
                           _, _, _, X, X, X, X, X, X, _, _, _,  
                           X, X, _, _, _, X, X, _, _, _, X, X,  
                           X, X, X, X, _, X, X, _, X, X, X, X,  
                           X, _, X, X, X, X, X, X, X, X, _, X,  
                           X, X, X, X, X, X, X, X, X, X, X, X,  
                           X, X, X, _, X, X, X, X, _, X, X, X,  
                           _, X, X, X, X, X, X, X, X, X, X, _,  
                           _, _, X, X, X, _, _, X, X, X, _, _,  
                           _, X, X, X, X, X, X, X, X, X, X, _   
                          };    
        pixelCoord tl = getTopLeftOfSquare(row, column);    
        uLCD.BLIT(tl.x + 2, tl.y + 2, 12, 12, sprite);  
    }

public:
    BoardState getBoardState()
    {
        return boardState;
    }

    void setBoardState(BoardState newBoardState)
    {
        boardState = newBoardState;
    }

    // initializes the starting board state
    GameBoard()
    {
        // draw board
        for (int row = 0; row < 8; row++) {
            for (int column = 0; column < 8; column++) {
                uint64_t color;
                if ((row + column) % 2 == 0) {
                    color = BOARD_DARK_COLOR;
                } else {
                    color = BOARD_LIGHT_COLOR;
                }
                pixelCoord tl = getTopLeftOfSquare(row, column);
                uLCD.filled_rectangle(tl.x, tl.y, tl.x + 15, tl.y + 15, color);
            }
        }
        // draw pieces
        placePieceAndDraw(wR, 0, 0);
        placePieceAndDraw(wN, 0, 1);
        placePieceAndDraw(wB, 0, 2);
        placePieceAndDraw(wQ, 0, 3);
        placePieceAndDraw(wK, 0, 4);
        placePieceAndDraw(wB, 0, 5);
        placePieceAndDraw(wN, 0, 6);
        placePieceAndDraw(wR, 0, 7);
        placePieceAndDraw(bR, 7, 0);
        placePieceAndDraw(bN, 7, 1);
        placePieceAndDraw(bB, 7, 2);
        placePieceAndDraw(bQ, 7, 3);
        placePieceAndDraw(bK, 7, 4);
        placePieceAndDraw(bB, 7, 5);
        placePieceAndDraw(bN, 7, 6);
        placePieceAndDraw(bR, 7, 7);
        for (int i = 0; i < 8; i++) {
            placePieceAndDraw(w, 1, i);
            placePieceAndDraw(b, 6, i);
        }
    }

    // PIECE MOVEMENT AND GRAPHICS FUNCTIONS

    // returns the piece at a given location
    Piece getPiece(boardPos pos)
    {
        return getPiece(pos.row, pos.column);
    }
    Piece getPiece(int row, int column)
    {
        return boardState.getPiece(row, column);
    }

    /*  puts the bit representation of a piece at the set position of the board
        assumes that the position of the board is emptied beforehand
    */
    void placePieceAndDraw(Piece piece, boardPos pos)
    {
        placePieceAndDraw(piece, pos.row, pos.column);
    }
    void placePieceAndDraw(Piece piece, int row, int column)
    {
        boardState.placePiece(piece, row, column);
        pixelCoord tl = getTopLeftOfSquare(row, column);
        switch(piece) { 
            case wK:    
            case bK:    
                drawKing(row, column, piece==wK, (row+column)%2);   
                break;  
            case wQ:    
            case bQ:    
                drawQueen(row, column, piece==wQ, (row+column)%2);  
                break;  
            case wB:    
            case bB:    
                drawBishop(row, column, piece==wB, (row+column)%2); 
                break;  
            case wN:    
            case bN:    
                drawKnight(row, column, piece==wN, (row+column)%2); 
                break;  
            case wR:    
            case bR:    
                drawRook(row, column, piece==wR, (row+column)%2);   
                break;  
            case w: 
            case b: 
                drawPawn(row, column, piece==w, (row+column)%2);    
                break;  
        }
    }

    /*  removes a piece from the set position of the board
        returns the bit representation of the piece
    */
    Piece removePieceAndDraw(boardPos pos)
    {
        return removePieceAndDraw(pos.row, pos.column);
    }
    Piece removePieceAndDraw(int row, int column)
    {
        Piece removedPiece = boardState.removePiece(row, column);
        pixelCoord tl = getTopLeftOfSquare(row, column);
        uint64_t color;
        if ((row + column) % 2 == 0) {
            color = BOARD_DARK_COLOR;
        } else {
            color = BOARD_LIGHT_COLOR;
        }
        uLCD.filled_rectangle(tl.x+2, tl.y+2, tl.x + 13, tl.y + 13, color);
        return removedPiece;
    }

    /*  moves a piece from one position to another
        returns the captured piece
    */
    Piece movePieceAndDraw(boardPos startPos, boardPos endPos)
    {
        return movePieceAndDraw(startPos.row, startPos.column, endPos.row, endPos.column);
    }
    Piece movePieceAndDraw(int startRow, int startColumn, int endRow, int endColumn)
    {
        Piece movingPiece = removePieceAndDraw(startRow, startColumn);
        Piece capturedPiece = boardState.removePiece(endRow, endColumn);
        placePieceAndDraw(movingPiece, endRow, endColumn);
        return capturedPiece;
    }

    // SQUARE BORDER GRAPHICS FUNCTIONS

    // removes selection border around square
    void unselectSquare(boardPos pos)
    {
        unselectSquare(pos.row, pos.column);
    }
    void unselectSquare(int row, int column)
    {
        if (row < 0 || row > 7 || column < 0 || column > 7) {
            return;
        }
        pixelCoord tl = getTopLeftOfSquare(row, column);
        uint64_t color;
        if ((row + column) % 2 == 0) {
            color = BOARD_DARK_COLOR;
        } else {
            color = BOARD_LIGHT_COLOR;
        }
        uLCD.rectangle(tl.x, tl.y, tl.x + 15, tl.y + 15, color);
    }

    // draws the hover border around square
    void hoverSquare(boardPos pos)
    {
        hoverSquare(pos.row, pos.column);
    }
    void hoverSquare(int row, int column)
    {
        pixelCoord tl = getTopLeftOfSquare(row, column);
        uLCD.rectangle(tl.x, tl.y, tl.x + 15, tl.y + 15, HOVER_COLOR);
    }

    // draws selection border around square
    void selectSquare(boardPos pos)
    {
        selectSquare(pos.row, pos.column);
    }
    void selectSquare(int row, int column)
    {
        if (row < 0 || row > 7 || column < 0 || column > 7) {
            return;
        }
        pixelCoord tl = getTopLeftOfSquare(row, column);
        uLCD.rectangle(tl.x, tl.y, tl.x + 15, tl.y + 15, SELECTED_COLOR);
    }

    // draws the movement border around square
    void movementSquare(boardPos pos)
    {
        movementSquare(pos.row, pos.column);
    }
    void movementSquare(int row, int column)
    {
        pixelCoord tl = getTopLeftOfSquare(row, column);
        uLCD.rectangle(tl.x, tl.y, tl.x + 15, tl.y + 15, MOVE_COLOR);
    }
};

// game variables
GameBoard gameBoard;
GameState state = whiteSelecting;
boardPos cursorPos = (boardPos)
{
    3, 4
};
boardPos selectedPos;
Piece selectedPiece;
std::vector<boardPos> possibleMoves;

// callbacks
void moveCursor(int rowChange, int columnChange)
{
    // calculate new positoin that is within board bounds
    int newRow = cursorPos.row + rowChange;
    newRow = newRow <= 7 ? newRow : 7;
    newRow = newRow >= 0 ? newRow : 0;
    int newColumn = cursorPos.column + columnChange;
    newColumn = newColumn <= 7 ? newColumn : 7;
    newColumn = newColumn >= 0 ? newColumn : 0;
    boardPos newPos = (boardPos) {
        newRow, newColumn
    };

    // draw border around square that should be there after moving cursor off
    if (cursorPos == selectedPos) {
        gameBoard.selectSquare(cursorPos);
    } else if (std::find(possibleMoves.begin(), possibleMoves.end(), cursorPos) != possibleMoves.end()) {
        gameBoard.movementSquare(cursorPos);
    } else {
        gameBoard.unselectSquare(cursorPos);
    }

    // draw hover rectangle over new square
    cursorPos = newPos;
    gameBoard.hoverSquare(cursorPos);
}

void joyStickUp()
{
    moveCursor(1, 0);
}

void joyStickDown()
{
    moveCursor(-1, 0);
}

void joyStickLeft()
{
    moveCursor(0, -1);
}

void joyStickRight()
{
    moveCursor(0, 1);
}

void joyStickPressed()
{
    switch(state) {
        case whiteSelecting:
        case blackSelecting: {
            possibleMoves.clear();
            selectedPos = cursorPos;
            Piece tempPiece = gameBoard.getPiece(cursorPos);
            std::vector<Piece> pickablePieces = state == whiteSelecting ? whitePieces : blackPieces;
            // check that piece is white and able to be picked up
            if (std::find(pickablePieces.begin(), pickablePieces.end(), tempPiece) != pickablePieces.end()) {
                selectedPiece = tempPiece;
                possibleMoves = gameBoard.getBoardState().getMoves(cursorPos);
                // draw movement squares
                for (std::vector<boardPos>::iterator it = possibleMoves.begin(); it != possibleMoves.end(); ++it) {
                    gameBoard.movementSquare(*it);
                }
                gameBoard.selectSquare(selectedPos);
                // transition state
                state = state == whiteSelecting ? whitePickedUp : blackPickedUp;
            } else {
                selectedPos = (boardPos)
                {
                    10, 10
                };
            }
            break;
        }
        case whitePickedUp:
        case blackPickedUp: {
            // check if move is valid
            if (std::find(possibleMoves.begin(), possibleMoves.end(), cursorPos) != possibleMoves.end()) {
                // move the piece
                Piece capturedPiece = gameBoard.movePieceAndDraw(selectedPos, cursorPos);
                // check for king capture
                if (state == whitePickedUp && capturedPiece == bK || state == blackPickedUp && capturedPiece == wK) {
                    // game end
                }
                // transition state
                state = state == whitePickedUp ? blackSelecting : whiteSelecting;
                // check if placing piece back down
            } else {
                // transition state
                state = state == whitePickedUp ? whiteSelecting : blackSelecting;
            }
            // unselect movement squares
            for (std::vector<boardPos>::iterator it = possibleMoves.begin(); it != possibleMoves.end(); ++it) {
                gameBoard.unselectSquare(*it);
            }
            gameBoard.unselectSquare(selectedPos);
            gameBoard.hoverSquare(cursorPos);
            possibleMoves.clear();
            selectedPos = (boardPos)
            {
                10, 10
            };
            break;
        }
        case whiteAI:
        case blackAI: {
            break;
        }
    }
}

Nav_Switch myNav(p9, p6, p7, p5, p8); //pin order on Sparkfun breakout

int main()
{
    //gameBoard = GameBoard();
    whitePieces.push_back(wK);
    whitePieces.push_back(wQ);
    whitePieces.push_back(wB);
    whitePieces.push_back(wN);
    whitePieces.push_back(wR);
    whitePieces.push_back(w);
    blackPieces.push_back(bK);
    blackPieces.push_back(bQ);
    blackPieces.push_back(bB);
    blackPieces.push_back(bN);
    blackPieces.push_back(bR);
    blackPieces.push_back(b);
    moveCursor(0, 0);
    while (1) {
        if (myNav.up()) {
            joyStickUp();
        } else if (myNav.down()) {
            joyStickDown();
        } else if (myNav.left()) {
            joyStickLeft();
        } else if (myNav.right()) {
            joyStickRight();
        } else if (myNav.fire()) {
            joyStickPressed();
        }
        wait(0.25);
    }
}