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

#define GREATER 2
#define SAME 1
#define LESSER 0

typedef struct lilyversion
{
	gint major;
	gint minor;
}lilyversion;

int
version_check(lilyversion base, lilyversion installed)
{
	if (base.major > installed.major)
		return LESSER;
	if (base.major < installed.major)
		return GREATER;
	if (base.minor == installed.minor)
		return SAME;
	if (base.minor > installed.minor)
		return LESSER;
	if (base.minor < installed.minor)
		return GREATER;

	/* if none of the above something is wrong */
	return -1;
}
	
	
lilyversion
string_to_lilyversion(char *string)
{
	lilyversion version;
	char **token;
	const char delimiters[] = ".";

	/* split string */
	token = g_strsplit(string, delimiters, 2);

	/* get major version number */
	version.major = atoi(token[0]);
	
	/* get minor version number */
	version.minor = atoi(token[1]);

	printf("\nstring_to_lilyversion() major = %d minor = %d\n",version.major, version.minor);
	return version;
}

gchar * 
find_decimal_dot_double_decimal (const gchar *string)
{
	GRegex *regex = NULL;
	GMatchInfo *match_info;
	GString *lilyversion = g_string_new ("");

	regex = g_regex_new("\\d.\\d\\d", 0, 0, NULL);
	g_regex_match(regex, string, 0, &match_info);

	if (g_match_info_matches (match_info))
        {
	  g_string_append(lilyversion, g_match_info_fetch (match_info, 0));
	}
	  
	g_match_info_free (match_info);
	g_regex_unref (regex);
	return g_string_free(lilyversion, FALSE); 	  
}

int
get_lily_version (void)
{
	GError *error = NULL;
	gchar *version_string;
	double d;
	int standard_output;
#define NUMBER_OF_PARSED_CHAR 30
	gchar buf[NUMBER_OF_PARSED_CHAR]; /* characters needed to parse */

	gchar *arguments[] = {
	  "lilypond",
	  "-v",
	  NULL
	};

	g_spawn_async_with_pipes (NULL,            /* dir */
	  arguments, NULL,       /* env */
	  G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD, NULL, /* child setup func */
	  NULL,          /* user data */
	  NULL,	/*pid*/
	  NULL, 	/*standard_input*/
	  &standard_output,	/*standard output*/
	  NULL,	/*standard error*/
	  &error);

	read(standard_output, buf, sizeof(buf));
	version_string = find_decimal_dot_double_decimal(buf);
	lilyversion installed_version = string_to_lilyversion(version_string);
	lilyversion check_version = string_to_lilyversion("2.8");

	return version_check(check_version, installed_version);
}


int 
main()
{
	gint version;
	version = get_lily_version();
	if (version == GREATER)
   	  g_print("\nInstalled Lilypond version is higher\n");
	if (version == SAME)
	  g_print("\nInstalled Lilypond version is same\n");
	if (version == LESSER)
	  g_print("\nInstalled Lilypond version is lower\n");
	if (version == -1)
	  g_print("\nerror finding lilypond version\n");

}