#include <string.h>

#include <stdio.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>

#include <assert.h>

#include <errno.h>

#include "syslog.h"

#define CONFIG_FILE "syslog.conf"

/* Data structures */

static struct

{

	int n; /* Number of config elements */

	struct config_element el[ETYPE_END];

} main_config;

/* Aquesta variable ha de reflexar l'ordre de la enum etype_config de syslog.h*/

const static struct config_element default_config[ETYPE_END+1] = {

	{ FROM_UNIX, "unixlog" },

	{ FROM_NPIPE, "disabled" },

	{ FROM_UDP, "disabled" },

	{ TO_UDP_HOST, "localhost" },

	{ TO_UDP_PORT, "1235" },

	{ TCP_MANAGER, "1234" },

	{ LOG_FILE, "file.log" },

	{ ETYPE_END, "" }};

/* Aquesta variable ha de reflexar l'ordre de la enum etype_config de syslog.h*/

const static struct {

	enum etype_config type;

	char string[MAX_STRING];

} etype_string[ETYPE_END+1] = {

	{ FROM_UNIX, "from_unix" },

	{ FROM_NPIPE, "from_npipe" },

	{ FROM_UDP, "from_udp" },

	{ TO_UDP_HOST, "to_udp_host" },

	{ TO_UDP_PORT, "to_udp_port" },

	{ TCP_MANAGER, "tcp_manager" },

	{ LOG_FILE, "log_file" },

	{ ETYPE_END, "" }};

/* Prototypes */

static int add_config_element(const char * restrict p, const char * restrict v,

		const int max);

static void read_config(char * restrict fname);

/* Functions' code */

void init_config()

{

	main_config.n = 0;

	read_config(CONFIG_FILE);

}

static void read_config(char * restrict fname)

{

	int file;

	char rchar;

	int res;

	char parameter[MAX_STRING];

	int nparameter;

	char value[MAX_STRING];

	int nvalue;

	enum {

		READ_PARAMETER,

		READ_VALUE

	} state;

	file = open(fname, O_RDONLY);

	if (file == -1)

	{

		fprintf(stderr,"The config file cannot be opened.\n");

		return;

	}

	nparameter=0;

	state=READ_PARAMETER;

	while ((res = read(file, &rchar, 1)) == 1)

	{

		switch (rchar)

		{

		case '=':

			assert(nparameter <= MAX_STRING);

			parameter[nparameter]='\0';

			nvalue=0;

			state=READ_VALUE;

			break;

		case '\n':

			if (state == READ_VALUE)

			{

				value[nvalue]='\0';

				assert( add_config_element(parameter,

							value, MAX_STRING)>=0);

			}

			nparameter=0;

			nvalue=0;

			state=READ_PARAMETER;

			break;

		default:

			switch(state)

			{

			case READ_PARAMETER:

				assert(nparameter <= MAX_STRING);

				parameter[nparameter++]=rchar;

				break;

			case READ_VALUE:

				assert(nvalue <= MAX_STRING);

				value[nvalue++]=rchar;

				break;

			}

		}

	}

	if (res == -1)

	{

		fprintf(stderr, "Error reading config file: %s\n",

				strerror(errno));

	}

	close(file);

}

/* Retorna el tipus si ha pogut afegir l'element, -1 si hi ha hagut error */

static int add_config_element(const char * restrict p, const char * restrict v,

		const int max)

{

	enum etype_config i, type;

	int j, pos;

	int my_max;

	my_max = max;

	if (my_max > MAX_STRING)

		my_max = MAX_STRING;

	/* busquem de quin paràmetre es tracta */

	for(i=0; i<ETYPE_END; i++)

	{

		/* a etype_string corresponen índex amb tipus */

		if (strncmp(p,etype_string[i].string, my_max) == 0)

		{

			type=i;

			break;

		}

	}

	if (i==ETYPE_END)

	{

		/* Si el paràmetre no és conegut... */

		return -1;

	}

	/* Busquem si el paràmetre ja està a la configuració main_config */

	for (j=0; j<main_config.n; j++)

	{

		if(main_config.el[j].type == type)

		{

			pos = j;

			break;

		}

	}

	if(j == main_config.n)

	{

		pos = j;

		main_config.n++;

		/* At maximum, there should be ETYPE_END elements) */

		assert(main_config.n <= ETYPE_END);

	}

	main_config.el[pos].type = type;

	strncpy(main_config.el[pos].value, v, MAX_STRING);

	return type;

}

/* Returns 2 on configured type, 1 on default value, 0 on disabled,

 * -1 on error */

int get_config(const enum etype_config type, char * restrict v, const int max)

{

	int j;

	enum {

		DISABLED=0,

		DEFAULT=1,

		CONFIGURED=2,

		ERROR=-1

	} ret;

	if (type < 0 || type >= ETYPE_END)

		return ERROR;

	for (j=0; j<main_config.n; j++)

	{

		if(main_config.el[j].type == type)

		{

			strncpy(v, main_config.el[j].value, max);

			ret = CONFIGURED;

			break;

		}

	}

	if(j == main_config.n)

	{

		strncpy(v, default_config[type].value, max);

		ret = DEFAULT;

	}

	if(strncmp(v, "disabled", max) == 0)

		return DISABLED;

	else

		return ret;

}