#include <stdio.h>
#include <stdlib.h>

#define DELAY  25
#define OFFSET 10
#define WIDTH  80
#define HEIGHT  30

void ask_user(int, int, int*, int*, int*, int*, int* );
void draw_line( int );
void draw_point(int, int, int, int, int, int, int);
void time_delay(int, int*, int);

int main(int argc, char **argv) 
{ 
    int i, delay, width, height, kount=0;
    int x0=0, y0=0, dirx=1, diry=1, max_time=1000;
    
    delay = (argv[1]?atoi(argv[1]):DELAY);
    width = (argv[1] && argv[2]?atoi(argv[2]):WIDTH);
    height = (argv[1] && argv[2] && argv[3]?atoi(argv[3]):HEIGHT);

    ask_user(width, height, &x0, &y0, &dirx, &diry, &max_time); 

    while(1) {
        system("clear");
        printf("\ntime=%d\n\n\n", kount);

        draw_line(width);
        draw_point(kount, width, height, x0, y0, dirx, diry);
        draw_line(width);
        fflush(stdout);

        time_delay(delay, &kount, max_time);
    }
    return 0;
}

void ask_user(int w, int h, int* x, int* y, int* dx, int *dy, int* m_t)
{
    int c;
    
    printf("Do you want to provide initial coordinates, direction, and simulation duration?\n");
    printf("(Yy/Nn) ");
    c = getchar();
    if((c=='Y') || (c=='y')){
        printf("Width = %d. Give me x0: ", w); 
        scanf("%d",x);
        printf("Height = %d. Give me y0: ", h); 
        scanf("%d",y);
        printf("Give me the vertical/horizontal ratio [v/h]: ");
        scanf("%d/%d", dy, dx);
        printf("Give me the number of frames: ");
        scanf("%d", m_t);
    }
    return;
}

void draw_line( int width )
{
    int i;
    for(i=0; i<OFFSET-1; i++)
        putchar(' ');
    putchar('|');
    for(i=0; i<width; i++) 
        putchar('-');
    putchar('|');    
    putchar('\n');
    return;
}


void draw_point( int k, int width, int height, int x0, int y0, int dirx, int diry )
{
    int i, j, xmov, ymov;
    char places[height+1][width+OFFSET+2];

    for(i=0; i<height; i++)
        for(j=0; j<width+OFFSET+2; j++)
            places[i][j] = ' '; 

    for(i=0; i<height; i++) {
        places[i][OFFSET-1] = '|'; 
        places[i][width+OFFSET] = 124;
        places[i][width+OFFSET+1] = '\0';
    }

    xmov = k + x0; /* add initial x-coordinate */
    if(xmov/width%2) 
        j = OFFSET+width-xmov%width;
    else
        j = OFFSET+xmov%width;

    ymov = (int)(k * (!dirx?height:((float)diry)/((float)dirx))); /* take direction into account */
    if(ymov < 0) 
        ymov = -ymov;
    ymov += y0;  /* add initial y-coordinate */
    if(ymov/height%2)
        i = height-ymov%height;
    else
        i = ymov%height;

    places[i][j] = 'o'; /* place the moving particle */

    if(i==0 || j==OFFSET || i == height || j == OFFSET+width)
        putchar(7); /* ascii for bell sound */

    for(i=0; i<height; i++) 
        printf("%s\n", places[i]);

    return;
}

void time_delay(int delay, int *k, int max_t)
{
    int s, t, stat=1;
    for(t=0; t<1000; t++) 
        for(s=0; s<1000*delay; s++);
    if((*k)++ > max_t)
       exit(stat);
    return;
}