#include <stdio.h>
#include <stdlib.h>

struct point {
	float x;
	float y;
};

int sort_get_index(float tab[], int top, float val) {
	int i;

	for(i=0; i<top; i++) {
		if(tab[i] >= val)
			return i;
	}

	return top;
}

void sort_insert_at(float tab[], int i, int top, float val) {
	int j;

	for(j=top; j>i; j--) {
		tab[j] = tab[j-1];
	}

	tab[i] = val;
}

void sort_insert(float tab[], int top, float val) {
	sort_insert_at(tab, sort_get_index(tab, top, val), top, val);
}

int nb_columns() {
	return 32;
}

int nb_lines() {
	return 16;
}

void grid_init(char grid[], char pixel) {
	int i;

	for(i=0; i<nb_columns() * nb_lines(); i++) {
		grid[i] = pixel;
	}
}

void grid_display(char grid[]) {
	int i, j;

	for(i=0; i<nb_lines(); i++) {
		for(j=0; j<nb_columns(); j++) {
			printf("%c", grid[i*nb_columns() + j]);
		}
		printf("\n");
	}
}

void plot_point(char grid[], int x, int y, char pixel) {
	if(x < 0 || y < 0 || x >= nb_columns() || y >= nb_lines()) {
		printf("Point (%d, %d) is out of range\n", x, y);
		exit(1);
	}

	grid[(nb_lines() - y - 1) * nb_columns() + x] = pixel;
}

void plot_vline(char grid[], int x, float fy0, float fy1, char pixel) {
	int y0 = fy0 + 0.5;
	int y1 = fy1 + 0.5;
	int y;

	if(y0 - 0.5 == fy0)
		y0--;

	for(y=y0; y<=y1; y++){
		plot_point(grid, x, y, pixel);
	}
}

void plot_poly_sweep(char grid[], struct point p[], int n, int x, char pixel) {
	printf("sweep %d:\n", x);
}

void plot_poly(char grid[], struct point p[], int n, char pixel) {
	int i;

	for(i=0; i<nb_columns(); i++)
		plot_poly_sweep(grid, p, n, i, pixel);
}

int main(int argc, char **argv) {
	char grid[nb_columns() * nb_lines()];
	struct point p[] = {
		{ 2, 13 },
		{ 10, 13 },
		{ 30, 7 },
		{ 10, 1 },
		{ 2, 1 },
		{ 18, 7 }
	};

	grid_init(grid, ' ');
	plot_poly(grid, p, 6, '-');
	grid_display(grid);

	return 0;
}