/*
 * Generate an image of random circles of random colors in random
 * locations.  Inputs the file name, dimensions, and number of
 * circles to generate.
 */

#include <iostream>
#include <cstdlib>
#include <algorithm>

#include <cmath>

#include <time.h>
#include "img.h"

using namespace std;

// Prompt and read a parameter.
template<typename Dtype>
Dtype prompt_read(string prompt)
{
	cout << prompt << ": ";
	Dtype ret;
	cin >> ret;
	return ret;
}

/*
 * Constraints on the random selection.
 */

// How far from the edges.
static const int MARGIN = 20;		// Center at least margin from edge
static const int MINRAD = 25;		// Minimum radius
static const int CLEAR = 5;		// Extra space in closest dim.
static const int MINDIM = 2*MARGIN+MINRAD+3*CLEAR; // Minimum image dimension.

// Generate a circle of random color and size at a random location.
void gen_circle(image& img)
{
	int mindir = min(img.rows(),img.cols());

	// Choose the center.
	int crow = rand() % (img.rows() - 2*MARGIN) + MARGIN;
	int ccol = rand() % (img.cols() - 2*MARGIN) + MARGIN;

	// Choose the diameter and radius.
	int dia = rand() % (mindir - CLEAR);
	int rad = dia/2;
	int radsq = rad*rad;

	// Compute the visible row range.
	int minrow = max(crow - rad, 0);
	int maxrow = min(crow + rad, img.rows()-1);

	// Draw the circle
	pixel c;
	c.random();
	for(int row = minrow; row <= maxrow; ++row) {
		int h = crow - row;
		int cdist = round(sqrt(radsq - h*h));
		int start = max(0, ccol - cdist);
		int end = min(ccol + cdist, img.cols()-1);
		for(int col = start; col <= end; ++col) 
			img.set(row, col, c);
	}
}

int main(int argc, char **argv)
{
	// Get file name.
	string fn;
	if(argc >= 2)
		fn = argv[1];
	else
		fn = prompt_read<string>("File name to write");

	// Get the number of rows.
	int nrow;
	if(argc >= 3)
		nrow = atoi(argv[2]);
	else
		nrow = prompt_read<int>("Number of rows");

	// Get the number of cols.
	int ncol;
	if(argc >= 4)
		ncol = atoi(argv[3]);
	else
		ncol = prompt_read<int>("Number of columns");

	if(nrow <= MINDIM || ncol <= MINDIM) {
		cerr << "Image size is too small" << std::endl;
		exit(2);
	}

	// Get the number of circles to generate.
	int ncircle;
	if(argc >= 5)
		ncircle = atoi(argv[4]);
	else
		ncircle = prompt_read<int>("Number of circles");

	// Make random stuff really random.
	srand(time(0));

	// Choose a background color and create the image filled with it.
	pixel bg;
	bg.random();
	image im(nrow, ncol, bg);

	// Add the circles.
	while(ncircle-- > 0)
		gen_circle(im);

	// Generate the image file.
	im.save(fn);
}