#include "library.h"

struct Actor
{ double xpos, ypos, speed, reach;
  int color, target;
  string victory;
};

const int num_actors = 3;
const int idx_boy = 0, idx_bull = 1, idx_tree = 2;
const int field_w = 800, field_h = 600;

Actor all[num_actors];

void init();      // a PROTOTYPE lets you move func def to the end
void draw();
void update(double t);
bool winner();

void main()
{ init();
  make_window(field_w, field_h);
  set_pen_width(5);
  draw();
  while (true)
  { wait(0.01);
    update(0.5);
    draw();
    if (winner())
      break; } }

void update(double t)
{ for (int i = 0; i < num_actors; i += 1)
  { double currx = all[i].xpos, curry = all[i].ypos;
    int idx_target = all[i].target;
    double targx = all[idx_target].xpos, targy = all[idx_target].ypos;
    double dir = atan2(targx-currx, targy-curry);
    double dx = all[i].speed * t * sin(dir), dy = all[i].speed * t * cos(dir);
    all[i].xpos += dx;
    all[i].ypos += dy; } }

double distance(double x1, double y1, double x2, double y2)
{ return sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2)); }

bool winner()
{ for (int i = 0; i < num_actors; i += 1)
  { double currx = all[i].xpos, curry = all[i].ypos;
    int idx_target = all[i].target;
    double targx = all[idx_target].xpos, targy = all[idx_target].ypos;
    double reach = all[i].reach;
    if (distance(currx, curry, targx, targy) < reach)
    { move_to(currx, curry);
      set_pen_color(all[i].color);
      write_string(all[i].victory);
      return true; } }
  return false; }  

void draw()
{ for (int i = 0; i < num_actors; i += 1)
  { set_pen_color(all[i].color);
    draw_point(all[i].xpos, all[i].ypos); } }

void init()
{
  all[idx_boy].xpos = 200;
  all[idx_boy].ypos = field_h - 5;
  all[idx_boy].speed = 1.3;
  all[idx_boy].color = color::blue;
  all[idx_boy].target = idx_tree;
  all[idx_boy].reach = 2;
  all[idx_boy].victory = "I'm Safe";
  all[idx_bull].xpos = 400;
  all[idx_bull].ypos = 150;
  all[idx_bull].speed = 1.3;
  all[idx_bull].color = color::red;
  all[idx_bull].target = idx_boy;
  all[idx_bull].reach = 3;
  all[idx_bull].victory = "Graaaaah! Chomp!";
  all[idx_tree].xpos = 700;
  all[idx_tree].ypos = 300;
  all[idx_tree].speed = 0;
  all[idx_tree].color = color::green;
  all[idx_tree].target = idx_tree;
  all[idx_tree].reach = 0;
  all[idx_tree].victory = "Tree Wins!";
}