var chessBoard = [];
var me = true;
var over = false;

//赢法数组
var wins = [];
//赢法统计数组
var myWin = [];
var computerWin = [];
for (var i = 0; i < 15; i++) {
    chessBoard[i] = [];
    for (var j = 0; j < 15; j++) {
        chessBoard[i][j] = 0;
    }
}
//赢法数组初始化
for (var i = 0; i < 15; i++) {
    wins[i] = [];
    for (var j = 0; j < 15; j++) {
        wins[i][j] = [];
    }
}

var count = 0;//赢法数量
//横线
for (var i = 0; i < 15; i++) {
    for (var j = 0; j < 11; j++) {
        for (var k = 0; k < 5; k++) {
            wins[i][j + k][count] = true;
        }
        count++;
    }
}
//竖线
for (var i = 0; i < 15; i++) {
    for (var j = 0; j < 11; j++) {
        for (var k = 0; k < 5; k++) {
            wins[j + k][i][count] = true;
        }
        count++;
    }
}
//斜线
for (var i = 0; i < 11; i++) {
    for (var j = 0; j < 11; j++) {
        for (var k = 0; k < 5; k++) {
            wins[i + k][j + k][count] = true;
        }
        count++;
    }
}
//反斜线
for (var i = 0; i < 11; i++) {
    for (var j = 14; j > 3; j--) {
        for (var k = 0; k < 5; k++) {
            wins[i + k][j - k][count] = true;
        }
        count++;
    }
}

for (var i = 0; i < count; i++) {
    myWin[i] = 0;
    computerWin[i] = 0;
}

var chess = document.getElementById('chess');
var context = chess.getContext('2d');
context.strokeStyle = "#BFBFBF";

var logo = new Image();
logo.src = "2.jpg";
logo.onload = function () {
    context.drawImage(logo, 0, 0, 450, 450);
    drawChessBoard();
}
var drawChessBoard = function () {
    for (var i = 0; i < 15; i++) {
        context.moveTo(15 + i * 30, 15);
        context.lineTo(15 + i * 30, 435);
        context.stroke();
        context.moveTo(15, 15 + i * 30);
        context.lineTo(435, 15 + i * 30);
        context.stroke();
    }
}

var oneStep = function (i, j, me) {
    context.beginPath();
    context.arc(15 + i * 30, 15 + j * 30, 13, 0, 2 * Math.PI);
    context.closePath();
    var gradient = context.createRadialGradient(15 + i * 30 + 2, 15 + i * 30 - 2, 13, 15 + i * 30 + 2, 15 + i * 30 - 2, 0);
    if (me) {
        gradient.addColorStop(0, "#0A0A0A");
        gradient.addColorStop(1, "#636766");
    } else {
        gradient.addColorStop(0, "#D1D1D1");
        gradient.addColorStop(1, "#F9F9F9");
    }
    context.fillStyle = gradient;
    context.fill();
}

chess.onclick = function (e) {
    if (over) {
        return;
    }
    if (!me) {
        return;
    }
    var x = e.offsetX;
    var y = e.offsetY;
    var i = Math.floor(x / 30);
    var j = Math.floor(y / 30);
    if (chessBoard[i][j] == 0) {
        oneStep(i, j, me);
        chessBoard[i][j] = 1;
        for (var k = 0; k < count; k++) {
            if (wins[i][j][k]) {
                myWin[k]++;
                computerWin[k] = 6;
                if (myWin[k] == 5) {
                    window.alert("you win");
                    over = true;
                }
            }
        }
        if (!over) {
            me = !me;
            computerAI();
        }
    }
}

var computerAI = function () {
    var myScore = [];
    var computerScore = [];
    var max = 0;//最高分数
    var u = 0, v = 0;//最高分数点坐标
    for (var i = 0; i < 15; i++) {
        myScore[i] = [];
        computerScore[i] = [];
        for (var j = 0; j < 15; j++) {
            myScore[i][j] = 0;
            computerScore[i][j] = 0;
        }
    }
    for (var i = 0; i < 15; i++) {
        for (var j = 0; j < 15; j++) {
            if (chessBoard[i][j] == 0) {
                for (var k = 0; k < count; k++) {
                    if(wins[i][j][k]){
                        if (myWin[k]==1) {
                            myScore[i][j] += 200;
                        }else if (myWin[k]==2) {
                            myScore[i][j] += 400;
                        }else if (myWin[k]==3) {
                            myScore[i][j] += 2000;
                        } else if (myWin[k]==4) {
                            myScore[i][j] += 11000;
                        }
                        if (computerWin[k]==1) {
                            computerScore[i][j] += 220;
                        }else if (computerWin[k]==2) {
                            computerScore[i][j] += 420;
                        }else if (computerWin[k]==3) {
                            computerScore[i][j] += 2200;
                        } else if (computerWin[k]==4) {
                            computerScore[i][j] += 21000;
                        }
                    }
                }
                if (myScore[i][j] > max) {
                    max = myScore[i][j];
                    u = i;
                    v = j;
                } else if (myScore[i][j]==max) {
                    if (computerScore[i][j] > computerScore[u][v]) {
                        u = i;
                        v = j;
                    }
                }
                if (computerScore[i][j] > max) {
                    max = computerScore[i][j];
                    u = i;
                    v = j;
                } else if (computerScore[i][j]==max) {
                    if (myScore[i][j] > myScore[u][v]) {
                        u = i;
                        v = j;
                    }
                }
            }
        }
    }
    oneStep(u, v, false);
    chessBoard[u][v] == 2;
    for (var k = 0; k < count; k++) {
        if (wins[u][v][k]) {
            computerWin[k]++;
            myWin[k] = 6;
            if (computerWin[k] == 5) {
                window.alert("computer win");
                over = true;
            }
        }
    }
    if (!over) {
        me = !me;
    }
};