int WhetherInView(Football *ball,Robot *dubu);
int WhetherInSide(Football *ball,Robot *dubu);
int TurnToBall(Football *ball,Robot *dubu);
int MoveToBall(Football *ball,Robot *dubu);
int DrawBall(Football *ball);
int DrawRobot(Robot *dubu);
int MeetBoundary(Football *ball,FootballPitch *pitch);
int MeetRobot(Football *ball,Robot *dubu);
int WhetherReverse(Robot *dubu);
int ReverseToGoal(Football *ball,Robot *dubu);
int ComputeShootAngle(Football *ball,Robot *dubu);
int ReverseFactor(Football *ball,Robot *dubu);

/*判斷球是否在機器人的正前方*/
int WhetherInView(Football *ball,Robot *dubu)
{
    float x1,y1,x2,y2,a1,a2,b1,b2,c1,c2;

    x1 = dubu->position_x + dubu->reverse_radius * cos(PI / 4 + dubu->direction_indicator);
    y1 = dubu->position_y - dubu->reverse_radius * sin(PI / 4 + dubu->direction_indicator);
    x2 = dubu->position_x + dubu->reverse_radius * cos(3 * PI / 4 + dubu->direction_indicator);
    y2 = dubu->position_y - dubu->reverse_radius * sin(3 * PI / 4 + dubu->direction_indicator);
    a1 = y2 - y1;
    b1 = x1 - x2;
    c1 = x2 * y1 - x1 * y2;

    x1 = dubu->position_x + dubu->reverse_radius * cos(5 * PI / 4 + dubu->direction_indicator);
    y1 = dubu->position_y - dubu->reverse_radius * sin(5 * PI / 4 + dubu->direction_indicator);
    x2 = dubu->position_x + dubu->reverse_radius * cos(7 * PI / 4 + dubu->direction_indicator);
    y2 = dubu->position_y - dubu->reverse_radius * sin(7 * PI / 4 + dubu->direction_indicator);
    a2 = y2 - y1;
    b2 = x1 - x2;
    c2 = x2 * y1 - x1 * y2;

    if((a1 * ball->ball_x + b1 * ball->ball_y + c1) * (a2 * ball->ball_x + b2 * ball->ball_y + c2) > 0)
        return 0;
    else    return 1;
}

/*判斷球是否在機器人的側面*/
int WhetherInSide(Football *ball,Robot *dubu)
{
    float x1,y1,x2,y2,a1,a2,b1,b2,c1,c2;

    x1 = dubu->position_x + dubu->reverse_radius * cos(PI / 4 + dubu->direction_indicator);
    y1 = dubu->position_y - dubu->reverse_radius * sin(PI / 4 + dubu->direction_indicator);
    x2 = dubu->position_x + dubu->reverse_radius * cos(7 * PI / 4 + dubu->direction_indicator);
    y2 = dubu->position_y - dubu->reverse_radius * sin(7 * PI / 4 + dubu->direction_indicator);
    a1 = y2 - y1;
    b1 = x1 - x2;
    c1 = x2 * y1 - x1 * y2;

    x1 = dubu->position_x + dubu->reverse_radius * cos(3 * PI / 4 + dubu->direction_indicator);
    y1 = dubu->position_y - dubu->reverse_radius * sin(3 * PI / 4 + dubu->direction_indicator);
    x2 = dubu->position_x + dubu->reverse_radius * cos(5 * PI / 4 + dubu->direction_indicator);
    y2 = dubu->position_y - dubu->reverse_radius * sin(5 * PI / 4 + dubu->direction_indicator);
    a2 = y2 - y1;
    b2 = x1 - x2;
    c2 = x2 * y1 - x1 * y2;

    if((a1 * ball->ball_x + b1 * ball->ball_y + c1) * (a2 * ball->ball_x + b2 * ball->ball_y + c2) > 0)
        return 0;
    else    return 1;
}

/*機器人向球的方向旋轉*/
int TurnToBall(Football *ball,Robot *dubu)
{
    float angle;

    if(ball->ball_x > dubu->position_x && ball->ball_y <= dubu->position_y)
    {
        dubu->direction = 0;
        dubu->position_x += dubu->small_speed * cos(dubu->decline);
        dubu->position_y -= dubu->small_speed * sin(dubu->decline);
        dubu->reverse_factor=ReverseFactor(ball,dubu);
        dubu->direction_indicator += dubu->reverse_factor * dubu->decline;
        if(dubu->direction_indicator >= 2 * PI)
            dubu->direction_indicator -= 2 * PI;
    }
    else if(ball->ball_x < dubu->position_x && ball->ball_y <= dubu->position_y)
    {
        dubu->direction = -PI;
        dubu->position_x -= dubu->small_speed * cos(dubu->decline);
        dubu->position_y -= dubu->small_speed * sin(dubu->decline);
        dubu->reverse_factor = ReverseFactor(ball,dubu);
        dubu->direction_indicator += dubu->reverse_factor * dubu->decline;
    }
    else if(ball->ball_x < dubu->position_x && ball->ball_y > dubu->position_y)
    {
        dubu->direction = -PI;
        dubu->position_x -= dubu->small_speed * cos(dubu->decline);
        dubu->position_y += dubu->small_speed * sin(dubu->decline);
        dubu->reverse_factor = ReverseFactor(ball,dubu);
        dubu->direction_indicator += dubu->reverse_factor * dubu->decline;
    }
    else if(ball->ball_x > dubu->position_x && ball->ball_y > dubu->position_y)
    {
        dubu->direction = -2*PI;
        dubu->position_x += dubu->small_speed * cos(dubu->decline);
        dubu->position_y += dubu->small_speed * sin(dubu->decline);
        dubu->reverse_factor = ReverseFactor(ball,dubu);
        dubu->direction_indicator += dubu->reverse_factor * dubu->decline;
        if(dubu->direction_indicator < 0)
            dubu->direction_indicator += 2 * PI;
    }
    else if(ball->ball_x == dubu->position_x && ball->ball_y < dubu->position_y)
    {
        dubu->direction = PI/2;
        dubu->position_x -= dubu->small_speed * cos(dubu->decline);
        dubu->position_y -= dubu->small_speed * sin(dubu->decline);
        dubu->reverse_factor = ReverseFactor(ball,dubu);
        dubu->direction_indicator += dubu->reverse_factor * dubu->decline;
    }
    else if(ball->ball_x == dubu->position_x && ball->ball_y > dubu->position_y)
    {
        dubu->direction = PI/2;
        dubu->position_x -= dubu->small_speed * cos(dubu->decline);
        dubu->position_y += dubu->small_speed * sin(dubu->decline);
        dubu->reverse_factor = ReverseFactor(ball,dubu);
        dubu->direction_indicator += dubu->reverse_factor * dubu->decline;
    }

    return 0;
}

/*當機器人對準了球時，正對著球前進*/
int MoveToBall(Football *ball,Robot *dubu)
{
    float x,y,d1,d2;

    x = dubu->position_x + dubu->forward_speed * cos(dubu->direction_indicator);
    y = dubu->position_y - dubu->forward_speed * sin(dubu->direction_indicator);
    d1 = (x - ball->ball_x) * (x - ball->ball_x) + (y - ball->ball_y) * (y - ball->ball_y);
    d2 = (dubu->position_x - ball->ball_x) * (dubu->position_x - ball->ball_x) + (dubu->position_y - ball->ball_y) * (dubu->position_y - ball->ball_y);
    if(d1 < d2)
    {
        dubu->position_x += dubu->forward_speed * cos(dubu->direction_indicator);
        dubu->position_y -= dubu->forward_speed * sin(dubu->direction_indicator);
    }
    else
    {
        dubu->position_x -= dubu->forward_speed * cos(dubu->direction_indicator);
        dubu->position_y += dubu->forward_speed * sin(dubu->direction_indicator);
    }

    return 0;
}

/*畫球的函數*/
int DrawBall(Football *ball)
{
    setfillstyle(1,ball->color);
    circle(ball->ball_x,ball->ball_y,ball->radius);
    floodfill(ball->ball_x,ball->ball_y,ball->color);

    return 0;
}

/*畫機器人的函數*/
int DrawRobot(Robot *dubu)
{
    setcolor(dubu->color);
    line(dubu->position_x + dubu->reverse_radius * cos ( PI / 4 + dubu->direction_indicator),dubu->position_y-dubu->reverse_radius*sin(PI/4+dubu->direction_indicator),dubu->position_x+dubu->reverse_radius*cos(3*PI/4+dubu->direction_indicator),dubu->position_y-dubu->reverse_radius*sin(3*PI/4+dubu->direction_indicator));
    line(dubu->position_x + dubu->reverse_radius * cos ( 3 * PI / 4 + dubu->direction_indicator),dubu->position_y-dubu->reverse_radius*sin(3*PI/4+dubu->direction_indicator),dubu->position_x+dubu->reverse_radius*cos(5*PI/4+dubu->direction_indicator),dubu->position_y-dubu->reverse_radius*sin(5*PI/4+dubu->direction_indicator));
    line(dubu->position_x + dubu->reverse_radius * cos ( 5 * PI / 4 + dubu->direction_indicator),dubu->position_y-dubu->reverse_radius*sin(5*PI/4+dubu->direction_indicator),dubu->position_x+dubu->reverse_radius*cos(7*PI/4+dubu->direction_indicator),dubu->position_y-dubu->reverse_radius*sin(7*PI/4+dubu->direction_indicator));
    line(dubu->position_x + dubu->reverse_radius * cos ( 7 * PI / 4 + dubu->direction_indicator),dubu->position_y-dubu->reverse_radius*sin(7*PI/4+dubu->direction_indicator),dubu->position_x+dubu->reverse_radius*cos(PI/4+dubu->direction_indicator),dubu->position_y-dubu->reverse_radius*sin(PI/4+dubu->direction_indicator));
    setfillstyle(1,dubu->color);
    floodfill(dubu->position_x,dubu->position_y,dubu->color);
    settextstyle(0,0,1);
    settextjustify(1,1);
    setcolor(WHITE);
    if(dubu->number == 1)
        outtextxy(dubu->position_x,dubu->position_y,"1");
    if(dubu->number == 2)
        outtextxy(dubu->position_x,dubu->position_y,"2");
    return 0;
}

/*二人足球中，機器人面對球門時，先判斷是否是自己要射的門，再決定是否執行射門動作*/
int WhetherReverse(Robot *dubu)
{
    int result;
    float a1,a2;

    if(dubu->direction_indicator >= 0 && dubu->direction_indicator < PI / 2)
        dubu->direction_indicator += 2 * PI;
    if(dubu->direction_indicator >= PI / 2 && dubu->direction_indicator < 3 * PI / 2)
    {
        a1 = PI + atan((dubu->position_y - 200) / (70 - dubu->position_x));
        a2 = PI + atan((dubu->position_y - 250) / (70 - dubu->position_x));
        if(dubu->direction_indicator > a1 && dubu->direction_indicator < a2 && dubu->number == 2)
            result = 0;
        else    result = 1;
    }
    else
    {
        a1 = 2 * PI + atan((dubu->position_y - 250) / (570 - dubu->position_x));
        a2 = 2 * PI + atan((dubu->position_y - 200) / (570 - dubu->position_x));
        if(dubu->direction_indicator > a1 && dubu->direction_indicator < a2 && dubu->number == 1)
            result = 0;
        else    result = 1;
    }
    if(dubu->direction_indicator > 2 * PI)
        dubu->direction_indicator -= 2 * PI;
    else if(dubu->direction_indicator < 0)
        dubu->direction_indicator += 2 * PI;

    return result;
}

/*射門動作的實現*/
int ReverseToGoal(Football *ball,Robot *dubu)
{
    int i,size;
    void *buffer;

    for(i=0;i<3;i++)
    {
        if(i==250)
            dubu->reverse_factor = -dubu->reverse_factor;
        dubu->direction_indicator += 16 * dubu->reverse_factor * dubu->decline;
        size = imagesize(dubu->position_x - dubu->reverse_radius,dubu->position_y - dubu->reverse_radius,dubu->position_x + dubu->reverse_radius,dubu->position_y + dubu->reverse_radius);
        buffer = malloc(size);
        getimage(dubu->position_x - dubu->reverse_radius,dubu->position_y - dubu->reverse_radius,dubu->position_x + dubu->reverse_radius,dubu->position_y + dubu->reverse_radius,buffer);
        if(buffer==0)
        {
            printf("error");
            exit(1);
        }
        DrawRobot(dubu);
        delay(2);
        putimage(dubu->position_x - dubu->reverse_radius,dubu->position_y - dubu->reverse_radius,buffer,COPY_PUT);
        free(buffer);
    }

    return 0;
}

/*二人足球中，判斷機器人的旋轉方向*/
int ComputeShootAngle(Football *ball,Robot *dubu)
{
    dubu->reverse_factor = -1;
    if(dubu->number == 1)
    {
        if(ball->ball_y >= dubu->position_y)
            dubu->reverse_factor = -1;
        else if(ball->ball_y < dubu->position_y)
            dubu->reverse_factor = 1;
    }
    if(dubu->number == 2)
    {
        if(ball->ball_y >= dubu->position_y)
            dubu->reverse_factor = 1;
        else if(ball->ball_y < dubu->position_y)
            dubu->reverse_factor = -1;
    }

    return 0;
}

/*計算機器人的旋轉方向，順時針為－1，逆時針為1*/
int ReverseFactor(Football *ball,Robot *dubu)
{
    int result;
    float angle;

    if(ball->ball_x > dubu->position_x && ball->ball_y <= dubu->position_y)
    {
        angle = atan((ball->ball_y - dubu->position_y) / (dubu->position_x - ball->ball_x));
        if((dubu->direction_indicator > 3 * PI / 2) && (dubu->direction_indicator < 2 * PI))
            result = 1;
        else if(dubu->direction_indicator < angle)
            result = 1;
        else    result = -1;
    }
    else if(ball->ball_x < dubu->position_x && ball->ball_y <= dubu->position_y)
    {
        angle = PI + atan((ball->ball_y - dubu->position_y) / (dubu->position_x - ball->ball_x));
        if(dubu->direction_indicator < angle)
            result = 1;
        else    result = -1;
    }
    else if(ball->ball_x < dubu->position_x && ball->ball_y > dubu->position_y)
    {
        angle = PI + atan((ball->ball_y - dubu->position_y) / (dubu->position_x - ball->ball_x));
        if(dubu->direction_indicator < angle)
            result = 1;
        else    result = -1;
    }
    else if(ball->ball_x > dubu->position_x && ball->ball_y > dubu->position_y)
    {
        angle = 2 * PI + atan((ball->ball_y - dubu->position_y) / (dubu->position_x - ball->ball_x));
        if((dubu->direction_indicator >= 0) && (dubu->direction_indicator < PI / 2))
            result = -1;
        else if(dubu->direction_indicator < angle)
            result = 1;
        else    result = -1;
    }
    else if(ball->ball_x == dubu->position_x && ball->ball_y < dubu->position_y)
    {
        angle = PI / 2;
        if(dubu->direction_indicator < angle)
            result = 1;
        else    result = -1;
    }
    else if(ball->ball_x == dubu->position_x && ball->ball_y > dubu->position_y)
    {
        angle = 3 * PI / 2;
        if(dubu->direction_indicator < angle)
            result = 1;
        else    result = -1;
    }

    return result;
}