// ----------------------------------------------------------------
// System Headers
// ----------------------------------------------------------------

#include <iostream>
#include <vector>
#include <cmath>

// ----------------------------------------------------------------
// Local Headers
// ----------------------------------------------------------------

#include "util.h"
#include "svg.h"

// ----------------------------------------------------------------
// Using Directives
// ----------------------------------------------------------------

using std::vector;

// ----------------------------------------------------------------
// Point
// ----------------------------------------------------------------

struct Point
{
   Point(int x, int y) : mX(x), mY(y)
   {
   }

   Point() : mX(0), mY(0)
   {
   }

   int mX;
   int mY;
};

// ----------------------------------------------------------------
// drawShape - Draw the outline represented by 'points'
// ----------------------------------------------------------------

static void drawShape(const vector<Point> &points, SVG *svg)
{
   for(int i = 0, n = points.size(); i < n; i ++)
   {
      svg->line(
         points[i].mX, points[i].mY,
         points[(i + 1) % n].mX, points[(i + 1) % n].mY,
         Colors::black
      );
   }
}

// ----------------------------------------------------------------
// getPoint - Find a point that is 'percent' of the way from
//            'p1' to 'p2'
// ----------------------------------------------------------------

Point getPoint(const Point &p1, const Point &p2, double percent)
{
   if(percent < 0.0)      percent = 0.0;
   else if(percent > 1.0) percent = 1.0;

   double xDelta = (p2.mX - p1.mX);
   double yDelta = (p2.mY - p1.mY);

   double r     = sqrt(xDelta * xDelta + yDelta * yDelta);
   double theta = atan2(yDelta, xDelta);

   double xNew = p1.mX + (percent * r) * cos(theta);
   double yNew = p1.mY + (percent * r) * sin(theta);

   return(Point(Util::rnd(xNew), Util::rnd(yNew)));
}

// ----------------------------------------------------------------
// getChild - Given 'points', generate the inscribed child
//            figure based on 'percent' and 'reverse'
// ----------------------------------------------------------------

vector<Point> getChild(
   const vector<Point> &points, double percent, bool reverse
)
{
   vector<Point> child;

   for(int i = 0, n = points.size(); i < n; i ++)
   {
      int index1 = i;
      int index2 = (reverse ? (i + n - 1) : (i + 1)) % n;

      child.push_back(getPoint(points[index1], points[index2], percent));
   }

   return(child);
}

// ----------------------------------------------------------------
// draw - Render our figure having 'nSides' and to 'depth'
//        based on 'percent' and 'reverse'
// ----------------------------------------------------------------

static void draw(
   int nSides, int depth, double percent, bool reverse, SVG *svg
)
{
   int w = svg->getWidth();
   int h = svg->getHeight();

   double radius = .45 * (w <= h ? w : h);
   int    step   = (360 / nSides);

   int xc = (w / 2);
   int yc = (h / 2);

   vector<Point> pts;

   for(int degrees = 0; degrees < 360; degrees += step)
   {
      double theta = Util::d2r(degrees + step / 2);

      double x = xc + radius * cos(theta);
      double y = yc + radius * sin(theta);

      pts.push_back(Point(Util::rnd(x), Util::rnd(y)));
   }

   for(int i = 0; i < depth; i ++, pts = getChild(pts, percent, reverse))
      drawShape(pts, svg);
}

// -------------------------------------
// main
// -------------------------------------

int main()
{
   static const int    WIDTH   = 500;
   static const int    HEIGHT  = 500;
   static const int    N_SIDES = 6;
   static const int    DEPTH   = 20;
   static const double PERCENT = .15;
   static const bool   REVERSE = true;

   SVG svg(WIDTH, HEIGHT);

   svg.border(Colors::black);

   draw(N_SIDES, DEPTH, PERCENT, REVERSE, &svg);

   string fileName = "spiral.html";
   string errMsg;

   if(!svg.write(fileName, errMsg))
      std::cout << errMsg << "\n";

   else
      std::cout << "Successfully wrote: " << fileName << "\n";

   return(0);
}