LLBot.js

var extend = require('./extend.js').extend,
    Board = require('./chessboard.js').Board,
    LiacBot = require('./base_client.js').LiacBot,
    
    // Constants
    DRAW_SCORE = 100000,
    MINIMAX_DEPTH = 3,
    Team = {
        WHITE : 1,
        BLACK : -1
    },
    
    // class LLBot extends LiacBot // (base_client)
    LLBot = extend(
        // Classe pai
        LiacBot,
        // Construtor
        function () {
            this.lastMove = null;
        },
        // Propriedades default e métodos
        {
            name: "LLBot",
            onMove: function (state) {
                console.log(state.board);
                console.log("Generating a move...");
                var board = new Board(state),
                    moves,
                    move;
                if (state.bad_move) {
                    console.log(state);
                }
                //moves = board.generate();
                //move = moves[Math.floor(Math.random() * moves.length)];
                move = this.chooseMove(board);
                this.last_move = move;
                this.sendMove(move.from, move.to);
            },
            onGameOver: function (state) {
                console.log('Game Over');
                console.log(state);
                console.log('---------');
            },
            estimateScore: function (board) {
                var score = 0;
                
                // Counts number of white pieces minus black pieces
                var x, y, p;
                for (x = 0; x < 8; x += 1) {
                    for (y = 0; y < 8; y += 1) {
                        p = board.cells[x][y];
                        if (p)
                            score += p.team;
                    }
                }
                return score;
            },
            // returns a move
            chooseMove: function (board) {
                return this.minimax(board, MINIMAX_DEPTH).move;
            },
            
            minimax : function (board, depth, maximizingPlayer) {
                if (depth == 0 || board.isTerminal()) {
                    
                    if (depth == 0) {
                        console.log("minimax depth end");
                    } else {
                        console.log("board is terminal");
                    }
                    
                    return { value: this.estimateScore(board), move: null };
                }
                
                var bestValue, val;
                var bestMove = null;
                
                if (board.whoMoves === Team.WHITE) {
                    // White moves, maximize value
                    bestValue = -Infinity;
                    
                    // Generate all possible moves
                    var possibleMoves = board.generate();
                    
                    // No possible moves, draw.
                    if (possibleMoves.length === 0) {
                        console.log("no moves for white");
                        return { value: board.whoMoves * DRAW_SCORE, move: null };
                    }
                    var that = this;
                    possibleMoves.forEach(function (move) {
                        val = that.minimax(board.afterMove(move), depth-1).value;
                        if (val > bestValue) {
                            bestValue = val;
                            bestMove = move;
                        }
                    });
                }
                else {
                    // Black moves, minimize value
                    bestValue = Infinity;
                    
                    // Generate all possible moves
                    var possibleMoves = board.generate();
                    
                    // No possible moves, draw.
                    if (possibleMoves.length === 0) {
                        console.log("no moves for black");
                        return { value: board.whoMoves * DRAW_SCORE, move: null };
                    }
                    var that = this;
                    possibleMoves.forEach(function (move) {
                        val = that.minimax(board.afterMove(move), depth-1).value;
                        if (val < bestValue) {
                            bestValue = val;
                            bestMove = move;
                        }
                    });
                }
                
                console.log("a minimax chosen step successful");
                return { value: bestValue, move: bestMove};
            }
        }
    );
exports.LLBot = LLBot;



//////////////////////////////////////////////////
// Main (para quando é executado diretamente)
//////////////////////////////////////////////////

function main() {
    var bot = new LLBot(),
        portIdx = process.argv.indexOf("-p"),
        hostIdx = process.argv.indexOf("-h"),
        port,
        host;
    if (process.argv.indexOf("--help") !== -1) {
        console.log("Usage: node LLBot.js [-p PORT] [-h HOST]");
        process.exit();
    }
    if (portIdx > 0) {
        port = parseInt(process.argv[portIdx + 1], 10);
    }
    if (hostIdx > 0) {
        host = process.argv[hostIdx + 1];
    }
    if (port) {
        bot.port = port;
    }
    if (host) {
        bot.ip = host;
    }
    bot.start();
}

if (require.main === module) {
    main();
}