#include <cairo/cairo.h>
#include <cairo/cairo-pdf.h>
#include <stdio.h>
#include <string.h>
#include "include/color.h"

double us_letter_paper_width = 8.5;
double us_letter_paper_height = 11;

double paper_width = 8.5 * 72; /* 612.0 */
double paper_height = 11 * 72; /* 792.0 */
int number_of_days = 30;
int rows = 6;
int columns = 7;
double margin = 0.5;

int draw_calendar(cairo_t *c, double x, double y) {
	double x1, y1, x2, y2;
	double month_width = us_letter_paper_width - (x * 2);
	double month_height = us_letter_paper_height - y - margin;
	double day_box_width = month_width / columns;
	double day_box_height = month_height / rows;

	x1 = x;
	y1 = y;
	x2 = us_letter_paper_width - x1; /* Set the line endpoint to right side of the page */

	for (int i = 0; i < rows + 1; i++) { /* Draw Horizontal Lines */
		cairo_move_to (c, x, y);
		cairo_line_to (c, x2, y);
		y = y + day_box_height;
	}

	x = x1;
	y = y1;
	y2 = y1 + month_height; /* Set the line endpoint as the bottom of the month */
	for (int i = 0; i < columns + 1; i++) { /* Draw Vertical Lines */
		cairo_move_to (c, x, y);
		cairo_line_to (c, x, y2);
		x = x + day_box_width;
	}
	cairo_stroke(c);
	return(0);
}

int draw_numbers(cairo_t *c, double x, double y, int wd) {
	double month_width = us_letter_paper_width - (x * 2);
	double month_height = us_letter_paper_height - y - margin;
	double day_box_width = month_width / columns;
	double day_box_height = month_height / rows;

	char str[3];
	cairo_text_extents_t te;
	cairo_font_extents_t fe;

	cairo_set_source_rgba(c, 0.0, 0.0, 0.0, 0.6);
	cairo_select_font_face (c, "sans-serif",
			CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_BOLD);
	cairo_set_font_size (c, 0.5);

	int iterative = 0;
	cairo_font_extents (c, &fe);
	double yi = y;
	double xi = x; 
	int current_weekday = wd;
	x = margin + (wd * day_box_width);
	for (int j = 0; j < rows; j++) {
		y = y + day_box_height - ((day_box_height - fe.ascent) / 2);
		for (int k = current_weekday; k < columns; k++) {
			if (iterative < number_of_days) {
				sprintf(str, "%d", iterative + 1);
				cairo_text_extents (c, str, &te);
				double box_margins = (day_box_width - te.width) / 2;

				cairo_move_to(c, x + box_margins - te.x_bearing, y); /* center the number within the box */
				cairo_show_text(c, str);
				cairo_move_to(c, x, y); /* Sort of backtrack to realign with the spacing of the boxes */
				x = x + day_box_width;
				iterative++;
				current_weekday++;
			}
		}
		current_weekday = 0;
		y = y - (day_box_height - ((day_box_height - fe.ascent) / 2));
		y = y + day_box_height;
		x = xi;
	}
	return(0);
}

int draw_month_name(cairo_t *c, char *name) {
	double x, y = margin;
	double month_width = us_letter_paper_width - (x * 2);
	double month_height = us_letter_paper_height - y - margin;
	double day_box_width = month_width / columns;
	double day_box_height = month_height / rows;
	cairo_set_source_rgb(c, 0.0, 0.0, 0.0);
	cairo_set_font_size(c, 1.0);
	cairo_text_extents_t te;
	cairo_font_extents_t fe;
	cairo_text_extents(c, name, &te);
	x = (us_letter_paper_width / 2) - (te.width / 2);
	y = 1.5;
	cairo_move_to(c, x, y);
	cairo_show_text(c, &name[0]);
	return(0);
}

int main (int argc, char *argv[]) {
	char date_strings[number_of_days][2];
	char months[12][10] = {"January", "February", "March", "April", "May",
		"June", "July", "August", "September", "October", "November", "December"};

	char weekdays_abbr[7][5] = {"Su", "Mo", "Tue", "Wed",
		"Thurs", "Fri", "Sat"};

	cairo_surface_t * surface = cairo_pdf_surface_create("0.pdf", paper_width, paper_height);
	cairo_t *cr = cairo_create(surface);

	cairo_scale(cr, 72, 72);
	cairo_set_line_width(cr, 0.03);
	cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 0.3);
	double month_origin_x = margin;
	double month_origin_y = 3.0;

	draw_calendar(cr, month_origin_x, month_origin_y);
	draw_numbers(cr, month_origin_x, month_origin_y, 6);
	draw_month_name(cr, months[10]);

	/* Clean Up */
	cairo_destroy(cr);
	cairo_surface_destroy(surface);

	return(0);
}