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

#include <iostream>
#include <sstream>
#include <vector>
#include <random>
#include <cmath>

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

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

// --------------------------------------------------------------
// Random
// --------------------------------------------------------------

class Random
{
   public:

      Random(int low, int high) : mDist(low, high)
      {
         seed();
      }

      Random(int high) : mDist(0, high)
      {
         seed();
      }

      int operator()()
      {
         return(mDist(mRng));
      }

   private:

      void seed() { mRng.seed(std::random_device()()); }

      std::mt19937 mRng;
      std::uniform_int_distribution<std::mt19937::result_type> mDist;
};

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

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

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

   string toString() const
   {
      std::ostringstream out;
      out << "(" << mX << ", " << mY << ")";
      return(out.str());
   }

   int mX;
   int mY;
};

// --------------------------------------------------------------
// Accept functions
// --------------------------------------------------------------

typedef bool (*AcceptFunction)(int, int);

static bool acceptOne(int next, int previous)
{
   return(next != previous);
}

static bool acceptTwo(int next, int previous)
{
   return(next != (previous + 1) % 4);
}

static bool acceptThree(int next, int previous)
{
   return(next != (previous + 2) % 4);
}

// --------------------------------------------------------------
// getCorners - Return a vector of Point corresponding to
//              'nSides', 'radius' and (xCenter, yCenter)
// --------------------------------------------------------------

static std::vector<Point> getCorners(
   int nSides, int xCenter, int yCenter, int radius
)
{
   vector<Point> corners;

   int step = (360 / nSides);

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

      int x = Util::rnd(xCenter + radius * cos(theta));
      int y = Util::rnd(yCenter + radius * sin(theta));

      corners.push_back(Point(x, y));
   }

   return(corners);
}

// --------------------------------------------------------------
// draw - Render our chaos game image
// --------------------------------------------------------------

static void draw(int nSides, SVG *svg, AcceptFunction accept)
{
   int w = svg->getWidth();
   int h = svg->getHeight();

   vector<Point> corners = getCorners(
      nSides, w / 2, h / 2, Util::rnd(.495 * (w >= h ? h : w))
   );

   Point current = corners[0];

   int count    = 0;
   int previous = 0;

   Random random(nSides - 1);

   while(count < 25000)
   {
      int next = random();

      if(accept(next, previous))
      {
         previous = next;

         current.mX = (current.mX + corners[next].mX) / 2;
         current.mY = (current.mY + corners[next].mY) / 2;

         svg->circle(current.mX, current.mY, 1, Colors::none, Colors::black);
         count++;
      }
   }
}

// --------------------------------------------------------------
// getFileName - Return a file name built from 'number', as in:
//               "chaos-" + number + ".html"
// --------------------------------------------------------------

static string getFileName(int number)
{
   std::ostringstream out;

   out << "chaos-" << number << ".html";

   return(out.str());
}

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

int main()
{
   static const AcceptFunction list[] = { acceptOne, acceptTwo, acceptThree };

   static const int WIDTH   = 750;
   static const int HEIGHT  = 750;
   static const int N_SIDES = 4;

   int index = 1;

   for(AcceptFunction accept : list)
   {
      SVG svg(WIDTH, HEIGHT);

      svg.border(Colors::black);

      draw(N_SIDES, &svg, accept);

      string fileName = getFileName(index++);
      string errMsg;

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

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

   return(0);
}