struct{
    char *ch;
    int color;
    char type;
}
charBorder = {"□", 4, 1},  //边框
charBg = {"■", 2, 2},  //背景
charSnake = {"★", 0xe, 3},  //贪吃蛇节点
charFood = {"●", 0xc, 4};  //食物

//用一个结构体数组保存地图中的各个点
struct{
    char type;
    int index;
}globalMap[MAXWIDTH][MAXHEIGHT];

//贪吃蛇有效活动范围地图的索引
struct{
    int x;
    int y;
} snakeMap[ (MAXWIDTH-2)*(MAXHEIGHT-2) ], scoresPostion;

int scores = 0;  //得分
int snakeMapLen = (MAXWIDTH-2)*(MAXHEIGHT-2);
int headerIndex, tailIndex;  //蛇头蛇尾对应的snakeMap中的索引（下标）
HANDLE hStdin;  //控制台句柄

// 设置光标位置，x为行，y为列
void setPosition(int x, int y){
    COORD coord;
    coord.X = 2*y;
    coord.Y = x;
    SetConsoleCursorPosition(hStdin, coord);
}

// 设置颜色
void setColor(int color){
    SetConsoleTextAttribute(hStdin, color);
}

//创建食物
void createFood(){
    int index, rang, x, y;
    //产生随机数，确定 snakeMap 数组的索引
    srand((unsigned)time(NULL));
    if(tailIndex<headerIndex){
        rang = headerIndex-tailIndex-1;
        index = rand()%rang + tailIndex + 1;
    }else{
        rang = snakeMapLen - (tailIndex - headerIndex+1);
        index = rand()%rang;
        if(index>=headerIndex){
            index += (tailIndex-headerIndex+1);
        }
    }

    x = snakeMap[index].x;
    y = snakeMap[index].y;
    setPosition(x, y);
    setColor(charFood.color);
    printf("%s", charFood.ch);
    globalMap[x][y].type=charFood.type;
}

//死掉
void die(){
    int xCenter = MAXHEIGHT%2==0 ? MAXHEIGHT/2 : MAXHEIGHT/2+1;
    int yCenter = MAXWIDTH%2==0 ? MAXWIDTH/2 : MAXWIDTH/2+1;

    setPosition(xCenter, yCenter-5);
    setColor(0xC);

    printf("You die! Game Over!");
    getch();
    exit(0);
}

// 蛇移动
void move(char direction){
    int newHeaderX, newHeaderY;  //新蛇头的坐标
    int newHeaderPreIndex;  //新蛇头坐标以前对应的索引
    int newHeaderPreX, newHeaderPreY;  //新蛇头的索引以前对应的坐标
    int newHeaderPreType;  //新蛇头以前的类型
    int oldTailX, oldTailY;  //老蛇尾坐标
    // -----------------------------------------------
    //新蛇头的坐标
    switch(direction){
        case 'w':
            newHeaderX = snakeMap[headerIndex].x-1;
            newHeaderY = snakeMap[headerIndex].y;
            break;
        case 's':
            newHeaderX = snakeMap[headerIndex].x+1;
            newHeaderY = snakeMap[headerIndex].y;
            break;
        case 'a':
            newHeaderX = snakeMap[headerIndex].x;
            newHeaderY = snakeMap[headerIndex].y-1;
            break;
        case 'd':
            newHeaderX = snakeMap[headerIndex].x;
            newHeaderY = snakeMap[headerIndex].y+1;
            break;
    }
    //新蛇头的索引
    headerIndex = headerIndex==0 ? snakeMapLen-1 : headerIndex-1;
    // -----------------------------------------------
    //新蛇头坐标以前对应的索引
    newHeaderPreIndex = globalMap[newHeaderX][newHeaderY].index;
    //新蛇头的索引以前对应的坐标
    newHeaderPreX = snakeMap[headerIndex].x;
    newHeaderPreY = snakeMap[headerIndex].y;

    //双向绑定新蛇头索引与坐标的对应关系
    snakeMap[headerIndex].x = newHeaderX;
    snakeMap[headerIndex].y = newHeaderY;
    globalMap[newHeaderX][newHeaderY].index = headerIndex;

    //双向绑定以前的索引与坐标的对应关系
    snakeMap[newHeaderPreIndex].x = newHeaderPreX;
    snakeMap[newHeaderPreIndex].y = newHeaderPreY;
    globalMap[newHeaderPreX][newHeaderPreY].index = newHeaderPreIndex;