/*
	genclockimg
	generates a clock face PNG image
*/

#include <cairo.h>
#include <popt.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <math.h>

#include "cairo_jpg.h"

int main (int argc, const char **argv)
{

	/* configuration options */
	int img_width;
	int img_height;
	char *img_filename;
	char img_filename_default[] = "out.png\0";
	char *timestr;
	
	int use_jpeg;
	
	/* timestamp represeting what time to draw */
	time_t clock_timestamp;
	struct tm *clock_localtime;
	int h;
	int m;

	/* cairo surface and context */
	cairo_surface_t *surface;
	cairo_t *context;
	
	/* popt options table */
	struct poptOption options_table[] = {
		{"out", 'o', POPT_ARG_STRING, &img_filename, 0, "output filename",  NULL },
		{"width", 'w', POPT_ARG_INT, &img_width, 0, "output image width", NULL },
		{"height", 'h', POPT_ARG_INT, &img_height, 0, "output image height", NULL },
		{"hours", '\0', POPT_ARG_INT, &h, 0, "hour to display", NULL },
		{"minutes", '\0', POPT_ARG_INT, &m, 0, "minutes to display", NULL },
		{"time", 't', POPT_ARG_STRING, &timestr, 0, "time to display as HH:MM", NULL},
		{"jpg", 'j', POPT_ARG_NONE, &use_jpeg, 0, "Write a JPEG file", NULL},
		POPT_AUTOHELP
		{NULL, '\0', 0, NULL, 0, NULL, NULL}
	};
	/* popt context */
	poptContext options_context;
		
	/* default filename is out.png */
	img_filename = NULL;	
	timestr = NULL;
	use_jpeg = 0;
	
	/* default image size is 128x128 */
	img_width = 128;
	img_height = 128;

	/* default timestamp is current localtime */
	clock_timestamp = time(NULL);
	clock_localtime = localtime(&clock_timestamp);
	h = clock_localtime->tm_hour % 12;
	m = clock_localtime->tm_min;
	
	/* parse command line options */
	options_context = poptGetContext(NULL, argc, argv, options_table, 0);

	int result;
	while ((result = poptGetNextOpt(options_context)) > 0 ) {
	}
	if (result < -1) {
		/* an error occurred during option processing */
		fprintf(stderr, "%s: %s\n", poptBadOption(options_context, POPT_BADOPTION_NOALIAS),poptStrerror(result));
		exit(1);
	}
	
	if (use_jpeg) {
		img_filename_default[4] = 'j';
		img_filename_default[5] = 'p';
		img_filename_default[6] = 'g';
	}
	
	if (img_filename == NULL) {
		img_filename = img_filename_default;
	}
	
	if (timestr != NULL ) {
		/* note: clock_localtime is already initialized here */
		strptime(timestr, "%H:%M", clock_localtime);
		h = clock_localtime->tm_hour % 12;
		m = clock_localtime->tm_min;
	}
	
	/* keep hours and minutes into range */
	h %= 12;
	m %= 60;	
	
	/* create the cairo drawing context and an RGBA drawing surface */	
	surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, img_width, img_height);
	context = cairo_create(surface);	

	/* draw image */
	cairo_set_source_rgba(context, 0.0, 0.0, 0.0, 1.0);
	cairo_rectangle(context, 0, 0, img_width, img_height);
	cairo_fill(context);
	
	int x1 = img_width / 2 -1;
	int y1 = img_height / 2 -1;

	float r;
	if (img_width < img_height) {
		r = img_width / 2;
	} else {
		r = img_height /2;
	}
	float angle = 2.0f * M_PI / 12.0f;
	
	/* draw clock background */
	/*
	cairo_set_source_rgba (context, 1.0, 1.0, 1.0, 1.0);
	cairo_arc(context, x1, y1, r-4, 0, 2 * M_PI);
	cairo_fill(context);
	*/
	/* draw clock face */
	cairo_set_source_rgba (context, 1.0, 1.0, 1.0, 1.0);
	cairo_set_line_width (context, 1);	
	cairo_arc(context, x1, y1, r-4, 0, 2 * M_PI);
	cairo_stroke(context);

	/* draw markers */
	cairo_set_source_rgba (context, 1.0, 1.0, 1.0, 1.0);
	cairo_set_line_width (context, 2);	
	for (int h = 0; h < 12; h++) {
		cairo_move_to(context, x1 + (r - 10) * cosf(angle * h), y1 + (r - 10) * sinf(angle * h));
		cairo_line_to(context, x1 + (r - 4) * cosf(angle * h), y1 + (r - 4)* sinf(angle * h));
	}
	cairo_stroke(context);
	
	/* draw handles */
	cairo_set_line_width (context, 4);
	
	/* hours handle */
	cairo_move_to(context, x1, y1);
	cairo_line_to(context, x1 + (r/2 - 4) * sinf(angle * h + angle / 60 * m), y1 - (r/2 - 4) * cosf(angle * h + angle / 60 * m));
	
	/* minutes handle */
	cairo_move_to(context, x1, y1);
	cairo_line_to(context, x1 + (r - 10) * sinf(M_PI / 30.0f * m ), y1 - (r - 10) * cosf(M_PI / 30.0f * m));
	cairo_stroke(context);
	
	
	/* write image file */
	cairo_status_t status = CAIRO_STATUS_SUCCESS;	
	if (use_jpeg) {
		status = cairo_image_surface_write_to_jpeg(surface, img_filename, 100);
	} else {
		status = cairo_surface_write_to_png(surface, img_filename);
	}
	if (status != CAIRO_STATUS_SUCCESS) {
		fprintf(stderr, "Error saving %s\n", img_filename);
	}

	/* cleanup */
	cairo_surface_destroy(surface);
	poptFreeContext(options_context);
	
	return 0;
}