#include <stddef.h>
#include <math.h>

#include "tectonics.h"
#include "geometry.h"
#include "drawing.h"

void get_cairo_size(cairo_t *cr, int *width, int *height)
{
   cairo_surface_t *surface = cairo_get_target(cr);
   *width = cairo_image_surface_get_width(surface);
   *height = cairo_image_surface_get_height(surface);
}


void draw_world(cairo_t *cr, struct world_t *world)
{
   int width, height;
   get_cairo_size(cr, &width, &height);
   double r = ((double)width) / (100*sqrt(world->n_points));
   cairo_set_source_rgba(cr, 1, 0, 0, 1);

   for (int i=0; i<world->n_points; i++) {
      struct point_t *pt = world->points + i;
      double xc = pt->x * width;
      double yc = pt->y * height;
      cairo_arc(cr, xc, yc, r, 0, 2*M_PI);
      cairo_stroke(cr);
   }

   //draw_quadtree(cr, &(world->tree));
}


void draw_quadtree(cairo_t *cr, struct quadtree_node_t *node)
{
   int width, height;
   get_cairo_size(cr, &width, &height);

   cairo_set_source_rgba(cr, 0, 0, 1, 1);
   struct point_t center = node->region.center;
   double half_dim = node->region.half_dim;

   double x = (center.x - half_dim) * width;
   double y = (center.y - half_dim) * height;
   
   cairo_rectangle(cr, x, y, 2*half_dim * width, 2*half_dim * height);
   cairo_stroke(cr);

   if (node->nw != NULL) {
      draw_quadtree(cr, node->nw);
      draw_quadtree(cr, node->ne);
      draw_quadtree(cr, node->sw);
      draw_quadtree(cr, node->se);
   }
}