#include <windows.h>
#include <time.h>

#define ID_TIMER    1   
#define TIMERSET    600 
char    score,temp=0;  
int     flag,tempx,tempy,
        foodx,foody,key;//运动方向，食物坐标，标记
bool    havebody[50][50]; 
bool    over = false;

struct Snake
{
    Snake *next;
    int x;
    int y;
}; 
struct Snake *head;
struct Snake *creat()//链表初始化
{
    struct Snake *p1,*p2,*p3;
    head=(struct Snake*)malloc(sizeof(Snake));
    p1=(struct Snake*)malloc(sizeof(Snake));
    p2=(struct Snake*)malloc(sizeof(Snake));
    p3=(struct Snake*)malloc(sizeof(Snake));
    
    head->x=23;head->y=23;
    head->next=p1;
    p1->x=24;p1->y=23;
    p1->next=p2; 
    p2->x=25;p2->y=23;
    p2->next=p3; 
    p3->x=26;p3->y=23;
    p3->next=NULL; 
    return head;
};
        
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    TCHAR        szAppName[]    = TEXT("dy");
    WNDCLASS    wndcls;
    wndcls.cbClsExtra        = 0;
    wndcls.cbWndExtra        = 0;
    wndcls.hbrBackground    = (HBRUSH) GetStockObject(WHITE_BRUSH);
    wndcls.hCursor            = LoadCursor(hInstance, IDC_ARROW);
    wndcls.hIcon            = LoadIcon(hInstance, IDI_APPLICATION);
    wndcls.hInstance        = hInstance;
    wndcls.lpfnWndProc        = WndProc;
    wndcls.lpszClassName    = szAppName;
    wndcls.lpszMenuName        = NULL;
    wndcls.style            = CS_HREDRAW | CS_VREDRAW;
    RegisterClass(&wndcls);

    HWND hwnd = CreateWindow (szAppName, TEXT ("dyww"),
                          WS_OVERLAPPEDWINDOW,
                           300, 100,
                          390, 400,
                          NULL, NULL, hInstance, NULL) ;
     
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

    MSG msg;
    while(GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}

void food(HWND hwnd)//食物
{
    foodx = rand() % 37, foody = rand() %36;
    while(havebody[foodx][foody])
    {
        foodx = rand() % 37, foody = rand() % 36;
    }
    havebody[foodx][foody] = true;
    InvalidateRect(hwnd, NULL, TRUE);
}

void  checkdeath()//检查是否死亡
{
    Snake *p= head,*end;
    do
    {    
        p=p->next;
    }while(p->next!=NULL);
    end=p;
    if(p->x <0||p->x >36 ||    p->y <0 ||    p->y >35)
    over=true;
    p=head->next;
    do
    {
        if(p->x==end->x&&p->y==end->y){over=true;}
        p=p->next;
    }while(p->next!=NULL);
}        
bool havefood(Snake *p)
{
    if(foodx==p->x&&foody==p->y)
        return true;
    else
        return false;
}

struct Snake *insert(int x,int y)//插入节点
{
    struct Snake *p1,*p;
    p=(struct Snake*)malloc(sizeof(Snake));
    p1=head;
    p->x=head->x;p->y=head->y;
    p->next=head->next;
    head->x=tempx;head->y=tempy;
    head->next=p;
    havebody[head->x][head->y]=true;
    return head;
};

Snake  *mainrun(HWND hwnd)
{
    struct Snake *p;
    p=head;
    int temp=0,deadfood=0;
    tempx=p->x;tempy=p->y;//储存头节点的值
        do
        {        
            if(p->next!=NULL){
                if(temp==0){havebody[p->x][p->y]=false; p->x=p->next->x;p->y=p->next->y;havebody[p->x][p->y]=true;temp++;}
            else 
                {p->x=p->next->x;p->y=p->next->y;havebody[p->x][p->y]=true;}}        
            p=p->next;    
        }while(p->next!=NULL);
        //havebody[p->x][p->y]=false;
        if(flag==1) p->x--;
        if(flag==2) p->y--;
        if(flag==3) p->x++;
        if(flag==4) p->y++;
        if(havefood(p))  {insert(tempx,tempy);deadfood=1;score+=1;}
        checkdeath();    
        havebody[p->x][p->y]=true;
        InvalidateRect(hwnd, NULL, TRUE);
    if(deadfood)  food(hwnd);
    return head;    
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)//窗口过程
{
    HDC                hdc;
    PAINTSTRUCT        ps;
    TCHAR            szScore[]=TEXT("GAME OVER 得分："),
                    szBuffer[20];
                
    int                x, y;

    switch(message)
    {
    case WM_CREATE://各种初始化
        flag=3;key=1;score=0;
        srand(time(NULL));
        creat();
        food(hwnd);
        havebody[foodx][foody]=true;
        SetTimer(hwnd, ID_TIMER, TIMERSET, NULL);
        return 0;

    case WM_TIMER:    
        mainrun(hwnd);
        if(over)
        {
            KillTimer(hwnd, ID_TIMER);
            InvalidateRect(hwnd, NULL, TRUE);
        }
        else InvalidateRect(hwnd, NULL, TRUE);
        return 0;

    case WM_KEYDOWN:
        if(over) return 0;
        switch(wParam)
        {
        case VK_UP:
            if(flag != 4)
            {
                flag = 2;
                mainrun(hwnd);
            }
            break;
        case VK_DOWN:
            if(flag != 2)
            {
                flag = 4;
                mainrun(hwnd);
            }
            break;
        case VK_LEFT:
            if(flag != 3)
            {
            flag = 1;
                mainrun(hwnd);
            }
            break;
        case VK_RIGHT:
            if(flag != 1)
            {
                flag = 3;
                mainrun(hwnd);
            }
            break;
        default:
            break;
        }
        return 0;

    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        Rectangle(hdc,0, 0,    370, 360);
        if(over)
            {SelectObject(hdc, GetStockObject(RGB(100,255,0)));Rectangle(hdc,0, 0,    370, 360);
            TextOut(hdc, 140, 130, szScore, lstrlen(szScore));
            TextOut(hdc, 178, 160,    szBuffer, wsprintf(szBuffer, TEXT("%4d"), score));
            //TextOut(hdc, 198, 190,    szBuffer, wsprintf(szBuffer, TEXT("%4d"), temp));
            }
         SelectObject(hdc, GetStockObject(BLACK_BRUSH));
        for(x = 0; x <37; x++)
            for(y = 0; y <36; y++)
            {    if(havebody[x][y])
                    Rectangle(hdc,x*10,y*10,(x+1)*10,(y+1)*10);
            }
        EndPaint (hwnd, &ps) ;
        return 0;

    case WM_DESTROY:
        KillTimer(hwnd, ID_TIMER);
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}