#include "library.h"

struct actor
{ string name;
  double x, y, speed;
  int colour, text_place;
  string victory_phrase;
  bool reached_target, can_still_win; };

void set(actor & a, string n, double ix, double iy, double spd, int col, string vp, int tp)
{ a.name = n;
  a.x = ix;
  a.y = iy;
  a.speed = spd;
  a.colour = col;
  a.victory_phrase = vp;
  a.text_place = tp;
  a.reached_target = false;
  a.can_still_win = true; }

void print(actor a)
{ cout << a.name << " at " << a.x << ", " << a.y << ", speed " << a.speed << "\n"; }

bool close(double a, double b)
{ return fabs(a-b) < 0.1; }

bool close(actor a, actor b)
{ return close(a.x, b.x) && close(a.y, b.y); }

double direction_from_a_to_b(actor a, actor b)
{ return atan2(b.x-a.x, a.y-b.y); }

void display_victory_phrase_for(actor a)
{ if (a.text_place==1)
    write_string(a.victory_phrase, direction::north_east);
  else if (a.text_place==2)
    write_string(a.victory_phrase, direction::south_east);
  else
    write_string(a.victory_phrase); }

void show_start_position(actor a)
{ set_pen_color(a.colour);
  move_to(a.x, a.y);
  write_string(a.name); }

void move_towards(actor & mover, actor target, double dt)
{       // the mover runs straight to the target:
        // work out the direction he runs
    double ang = direction_from_a_to_b(mover, target);
        // work out how far he runs in 0.1 seconds
    double dist = mover.speed * dt;
        // work out where he will be 0.1 seconds later
    double mover_new_x = mover.x + dist * sin(ang);
    double mover_new_y = mover.y - dist * cos(ang);
        // draw a line showing these few inches of progress
    set_pen_color(mover.colour);
    move_to(mover.x, mover.y);
    draw_to(mover_new_x, mover_new_y);
    mover.x = mover_new_x;
    mover.y = mover_new_y;
        // has he reached the target yet?
    if (close(mover, target))
    { if (mover.can_still_win)
        display_victory_phrase_for(mover);
      mover.reached_target = true; } }

void main()
{ double field_w=500, field_h=400, edge=100;
  actor tree, bull, boy, dinosaur;
  set(tree, "tree", 400, 400, 0, color::brown, "", 1);
  set(bull, "bull", 500, 150, 3, color::red, "Boy Eaten!", 1);
  set(dinosaur, "dinosaur", 150, 150, 3, color::purple, "Graaaaah!", 2);
  set(boy, "boy", 100, 500, 2, color::blue, "Boy Safe", 1);
  double bull_spd=3, delta_t=0.003;
  double total_time = 0.0;

  make_window(field_w+2*edge, field_h+2*edge);
  set_pen_color(color::green);
  fill_rectangle(edge, edge, field_w, field_h);
  set_pen_color(color::brown);
  set_pen_width(10);
  draw_point(tree.x, tree.y);
  set_pen_width(2);

  show_start_position(boy);
  show_start_position(bull);
  show_start_position(dinosaur);
  while (true)
  { move_towards(dinosaur, bull, delta_t);
    if (dinosaur.reached_target)
    { bull.can_still_win = false;
      bull.speed = 0; }
    move_towards(boy, tree, delta_t);
    if (boy.reached_target)
      bull.can_still_win = false;
    move_towards(bull, boy, delta_t);
    if (bull.reached_target)
    { boy.can_still_win = false;
      boy.speed = 0; } }
  cout << "Finished\n"; }