/*
 * configfile.c
 * This file is part of LCDd, the lcdproc server.
 *
 * This file is released under the GNU General Public License. Refer to the
 * COPYING file distributed with this package.
 *
 * Copyright (c) 2001, Joris Robijn
 *           (c) 2003, Rene Wagner
 *
 *
 * Defines routines to read ini-file-like files.
 * Optionally retrieves settings from an LDAP directory (OpenLDAP 2.1.x)
 */

#include "config.h"

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

#ifdef WITH_LDAP_SUPPORT
# include <ldap.h>
#endif /* WITH_LDAP_SUPPORT */

#include "shared/report.h"
#include "shared/fileio.h"


typedef struct key {
	char * name;
	char * value;
	struct key * next_key;
} key;

typedef struct section {
	char * name;
	key * first_key;
	struct section * next_section;
} section;


static section * first_section = NULL;
/* Yes there is a static. It's C after all :)*/


section * find_section( char * sectionname );
section * add_section( char * sectionname );
key * find_key( section * s, char * keyname, int skip );
key * add_key( section * s, char * keyname, char * value );
char get_next_char_f(buffile * f);
int process_config( section ** current_section, char (*get_next_char)(), char modify_section_allowed, char * source_descr, buffile * f );

#ifdef WITH_LDAP_SUPPORT
int connect_to_ldap(void);

static LDAP * ld = NULL;
int use_ldap=0;

static char * ldap_host=NULL, * ldap_base_dn=NULL;
int ldap_port;

/* not supported for now
 * char ldap_user[255] = "",
 *      ldap_pwd[255]  = "";
 */
#endif /* WITH_LDAP_SUPPORT */

/**** EXTERNAL FUNCTIONS ****/

int config_read_file( char *filename )
{
	buffile * f;
	section * curr_section = NULL;

#ifdef WITH_LDAP_SUPPORT
	LDAPURLDesc * url = NULL;
	int retval;
#endif /* WITH_LDAP_SUPPORT */   

	report( RPT_NOTICE, "Using Configuration File: %s", filename);

#ifdef WITH_LDAP_SUPPORT
	if (ldap_is_ldap_url( filename )) {
		use_ldap=1;
		
		if (0 != (retval = ldap_url_parse( filename, &url))) {
			report( RPT_ERR, "Errors parsing LDAP URL %s: %s", filename, ldap_err2string(retval));
			ldap_free_urldesc(url);
			return (-1);
		}

		ldap_host=strdup(url->lud_host);
		ldap_port=url->lud_port;
		report( RPT_INFO, "Using LDAP server: %s:%d", ldap_host, ldap_port);

		ldap_base_dn=strdup(url->lud_dn);
		report( RPT_INFO, "Using LDAP base DN: %s", ldap_base_dn);

		ldap_free_urldesc(url);

		if (connect_to_ldap() < 0 ) {
			debug( RPT_DEBUG, "connect_to_ldap returned errors.");
			return (-1);
		}

		return 0;
	}
#endif /* WITH_LDAP_SUPPORT */ 

	f = buffile_open( filename, "r" );
	if( f==NULL ) {
		return -1;
	}

	process_config( &curr_section, get_next_char_f, 1, filename, f );

	buffile_close( f );

	return 0;
}


int config_read_string( char *sectionname, char *str )
/* All the config parameters are placed in the given section in memory.*/
{
	int pos=0;
	section * s;

	/* We use a nested fuction to transfer the characters from buffer to parser*/
	char get_next_char() {
		return str[pos++];
	}

	if( !( s=find_section( sectionname ))) {
		s=add_section( sectionname );
	}

	process_config( &s, get_next_char, 0, "command line", NULL );

	return 0;
}


char *config_get_string( char * sectionname, char * keyname,
		int skip, char * default_value )
{
	section * s;
	key * k;

	s = find_section( sectionname );
	if( !s ) return default_value;
	k = find_key( s, keyname, skip );
	if( !k ) return default_value;

	return k->value;

/* This is the safer way:*/

	/* Reallocate memory space for the return value*/
	/*
	string_storage = realloc( string_storage, ( strlen( k->value ) / 256 + 1) * 256 );
	strcpy( string_storage, k->value );

   But then you also need a global static string_storage = NULL;
*/
}


short config_get_bool( char *sectionname, char *keyname,
		int skip, short default_value )
{
	section * s;
	key * k;

	s = find_section( sectionname );
	if( !s ) return default_value;
	k = find_key( s, keyname, skip );
	if( !k ) return default_value;

	if( strcasecmp( k->value, "0" )==0 || strcasecmp( k->value, "false" )==0
	|| strcasecmp( k->value, "n" )==0 || strcasecmp( k->value, "no" )==0 ) {
		return 0;
	}
	if( strcasecmp( k->value, "1" )==0 || strcasecmp( k->value, "true" )==0
	|| strcasecmp( k->value, "y" )==0 || strcasecmp( k->value, "yes" )==0 ) {
		return 1;
	}
	return default_value;
}


long int config_get_int( char *sectionname, char *keyname,
		int skip, long int default_value )
{
	section * s;
	key * k;
	long int v;
	char * v_end;

	s = find_section( sectionname );
	if( !s ) return default_value;
	k = find_key( s, keyname, skip );
	if( !k ) return default_value;

	v = strtol( k->value, &v_end, 0 );
	if( v_end-(k->value) != strlen(k->value) ) {
		/* Conversion not succesful*/
		return default_value;
	}
	return v;
}


double config_get_float( char *sectionname, char *keyname,
		int skip, double default_value )
{
	section * s;
	key * k;
	double v;
	char * v_end;

	s = find_section( sectionname );
	if( !s ) return default_value;
	k = find_key( s, keyname, skip );
	if( !k ) return default_value;

	v = strtod( k->value, &v_end );
	if( v_end-(k->value) != strlen(k->value) ) {
		/* Conversion not succesful*/
		return default_value;
	}
	return v;
}


int config_has_section( char *sectionname )
{
	section * s;

	s = find_section( sectionname );
	if( s ) return 1; else return 0;
}


int config_has_key( char *sectionname, char *keyname )
{
	section * s;
	key * k;

	int count = 0;

	s = find_section( sectionname );
	if( !s ) return 0;

	for( k=s->first_key; k; k=k->next_key ) {

		/* Did we find the right key ?*/
		if( strcasecmp( k->name, keyname ) == 0 ) {
			count ++;
		}
	}
	return count;
}


void config_clear()
{
	section * s;
	section * next_s;
	key * k;
	key * next_k;

	for( s = first_section; s; ) {
		for( k=s->first_key; k; ) {
			/* Advance before we destroy the current key */
			next_k = k->next_key;

			free( k->name );
			free( k->value );
			free( k );

			k = next_k;
		}
		/* Advance before we destroy the current section */
		next_s = s->next_section;

		/* And destroy it */
		free( s->name );
		free( s );

		s = next_s;
	}
	/* And make everything inaccessable */
	first_section = NULL;
}


/**** INTERNAL FUNCTIONS ****/

#ifdef WITH_LDAP_SUPPORT
int
connect_to_ldap (void)
{
	int retval;
	LDAPMessage * res;

	debug( RPT_INFO, "Connecting to LDAP server: %s:%d", ldap_host, ldap_port);

	if (!(ld = ldap_init(ldap_host, ldap_port))) {
		report(RPT_ERR, "LDAP session could not be initialized.");
		return (-1);
	}

/*****************************************************
 * disabled unless you really have a DN/pwd to bind to
 * WARNING: LCDd should not have LDAP write access!!
 *
 *	if (LDAP_SUCCESS != (retval = ldap_simple_bind_s (ld, ldap_user, ldap_pwd))) {
 *		report (RPT_ERR, "LDAP login on %s:%d failed: %s", ldap_host, ldap_port, ldap_err2string (retval));
 *		ldap_unbind (ld);
 *		ld = NULL;
 *		
 *		return (-1);
 *	}
 *	fprintf(stderr, "LDAP login successful on %s:%d\n", ldap_host, ldap_port);
 ********************************************************/
 
	/* check for the existence of the config object... */
	if (LDAP_SUCCESS != (retval = ldap_search_s (ld, ldap_base_dn, LDAP_SCOPE_BASE, "objectClass=lcdprocConfig", NULL, 0, &res))) {
		report( RPT_ERR, "Could not access LDAP server on %s:%d", ldap_host, ldap_port);
		return (-1);
	}
	if (0 == ldap_count_entries(ld, res)) {
		report( RPT_ERR, "No configuration object found in LDAP at: %s", ldap_base_dn);
		return (-1);
	}
	debug( RPT_DEBUG, "Configuration LDAP object found.");
	return 0;
}

#define BUFSIZE 255
#endif /* WITH_LDAP_SUPPORT */

section * find_section( char * sectionname )
{
	section * s;

#ifdef WITH_LDAP_SUPPORT
	LDAPMessage * res;
	int retval;
	char *filter=NULL;

	if (use_ldap) {
		debug( RPT_DEBUG, "Searching LDAP for section [%s]", sectionname);
		if (NULL == (filter = malloc(BUFSIZE))){
			report( RPT_ERR, "Could not allocate memory in find_section()");
			return NULL;
		}
		strcpy(filter, "cn=");
		strncat(filter, sectionname, BUFSIZE);
		if (LDAP_SUCCESS != (retval = ldap_search_s (ld, ldap_base_dn, LDAP_SCOPE_ONELEVEL, filter, NULL, 0, &res))) {
			if (NULL != filter) {
				free(filter);
				filter=NULL;
			}
			ldap_msgfree(res);
			report( RPT_ERR, "Could not access LDAP server on %s:%d", ldap_host, ldap_port);
			return NULL;
		}
		if (NULL != filter) {
			free(filter);
			filter=NULL;
		}
		if (0 == ldap_count_entries( ld, res )) {
			debug( RPT_DEBUG, "Section [%s] not found in LDAP.", sectionname);
			return NULL;
		}
		ldap_msgfree(res);
		debug( RPT_DEBUG, "Found section [%s] in LDAP", sectionname);
		s = (section*) malloc( sizeof( section ));
		s->name=strdup( sectionname );
		s->first_key = NULL;
		s->next_section = NULL;
		return s;
	}
#endif /* WITH_LDAP_SUPPORT */

	for( s=first_section; s; s=s->next_section ) {
		if( strcasecmp( s->name, sectionname ) == 0 ) {
			return s;
		}
	}
	return NULL; /* not found*/
}

section * add_section( char * sectionname )
{
	section *s;
	section ** place = &first_section;

	for( s=first_section; s; s=s->next_section )
		place = &(s->next_section);

	*place = (section*) malloc( sizeof( section ));
	(*place)->name = strdup( sectionname );
	(*place)->first_key = NULL;
	(*place)->next_section = NULL;

	return (*place);
}

key * find_key( section * s, char * keyname, int skip )
{
	key * k;
	int count = 0;
	key * last_key = NULL;

#ifdef WITH_LDAP_SUPPORT	
	LDAPMessage * res;
	LDAPMessage * entry;
	int retval;
	char *buf=NULL;
	char **vals;
#endif /* WITH_LDAP_SUPPORT */

	/* Check for NULL section*/
	if(!s) return NULL;

#ifdef WITH_LDAP_SUPPORT
	if (use_ldap) {
		debug( RPT_DEBUG, "Searching LDAP for key '%s' in section [%s] skipping %d entries.", keyname, s->name, skip);

		if (NULL == (buf = malloc(BUFSIZE))){
			report (RPT_ERR, "Could not allocate memory in find_key().");
		}
		strcpy(buf, "cn=");
		strncat(buf, s->name, BUFSIZE);
		if (LDAP_SUCCESS != (retval = ldap_search_s (ld, ldap_base_dn, LDAP_SCOPE_ONELEVEL, buf, NULL, 0, &res))) {
			if (NULL != buf) {
				free(buf);
				buf=NULL;
			}
			ldap_msgfree(res);
			report( RPT_ERR, "Could not access LDAP server on %s:%d", ldap_host, ldap_port);
			return NULL;
		}
		if (NULL == (entry = ldap_first_entry( ld, res ))) {
			debug( RPT_DEBUG, "Section [%s] not found in LDAP.", s->name);
			if (NULL != buf) {
				free(buf);
				buf=NULL;
			}
			/* DON'T enable the following
			 * ldap_msgfree(entry);
			 * ldap_msgfree below does that already
			 */
			ldap_msgfree(res);
			return NULL;
		}

		
		strcpy(buf, "lcdproc");
		strncat(buf, keyname, BUFSIZE);
		/* debug( RPT_DEBUG, "Key name translated to attribute name: %s", buf); */
		vals = ldap_get_values (ld, entry, buf);
		
		if (skip+1 > ldap_count_values (vals)) {
			debug( RPT_DEBUG, "No such entry found.");
			if (NULL != buf) {
				free(buf);
				buf=NULL;
			}
			ldap_value_free(vals);
			/* DON'T enable the following
			 * ldap_msgfree(entry);
			 * ldap_msgfree below does that already
			 */
			ldap_msgfree(res);
			return NULL;
		}
		/* DON'T enable the following
		 * ldap_msgfree(entry);
		 * ldap_msgfree below does that already
		 */
		ldap_msgfree(res);
		if (vals && vals[skip]) {
			if (NULL != buf) {
				free(buf);
				buf=NULL;
			}
			buf=strdup(vals[skip]);
			debug( RPT_DEBUG, "Entry found. Value is: %s", buf);
			ldap_value_free (vals);
						
			k=(key*) malloc( sizeof( key ));
			k->name = strdup( keyname );
			k->value = strdup( buf );
			k->next_key = NULL;
			
			if (NULL != buf) {
				free(buf);
				buf=NULL;
			}
			return k;
		} 
		report( RPT_ERR, "LDAP server encountered errors.");
		ldap_value_free (vals);
		if (NULL != buf) {
			free(buf);
			buf=NULL;
		}
		return NULL;
	}
#endif /* WITH_LDAP_SUPPORT */

	for( k=s->first_key; k; k=k->next_key ) {

		/* Did we find the right key ?*/
		if( strcasecmp( k->name, keyname ) == 0 ) {
			if( count == skip ) {
				return k;
			} else {
				count ++;
				last_key = k;
			}
		}
	}
	if( skip == -1 ) {
		return last_key;
	}
	return NULL; /* not found*/
}

key * add_key( section * s, char * keyname, char * value )
{
	key * k;

	key ** place = &( s->first_key );

	for( k=s->first_key; k; k=k->next_key )
		place = &(k->next_key);

	*place = (key*) malloc( sizeof( key ));
	(*place)->name = strdup( keyname );
	(*place)->value = strdup( value );
	(*place)->next_key = NULL;

	return (*place);
}

char get_next_char_f(buffile * f) {
	char * buf = buffile_read(f, 1);
	char c = buf[0];
	free(buf);
	return c;
}


/* Parser states*/
#define ST_INITIAL 0
#define ST_IGNORE 1
#define ST_SECTIONNAME 2
#define ST_KEYNAME 3
#define ST_VALUE 10
#define ST_QUOTEDVALUE 11
#define ST_QUOTEDVALUE_ESCCHAR 12
#define ST_INVALID_SECTIONNAME 23
#define ST_INVALID_KEYNAME 24
#define ST_INVALID_VALUE 30
#define ST_INVALID_QUOTEDVALUE 31
#define ST_END 99

/* Limits*/
#define MAXSECTIONNAMELENGTH 40
#define MAXKEYNAMELENGTH 40
#define MAXVALUELENGTH 200



int process_config( section ** current_section, char (*get_next_char)(), char modify_section_allowed, char * source_descr, buffile * f)
{
	char state = ST_INITIAL;
	char ch;
	char sectionname[MAXSECTIONNAMELENGTH+1];
	int sectionname_pos = 0;
	char keyname[MAXKEYNAMELENGTH+1];
	int keyname_pos = 0;
	char value[MAXVALUELENGTH+1];
	int value_pos = 0;
	int quote = 0;
	key * k;
	int line_nr = 1;

	while( state != ST_END ) {

		if (NULL != f) {
			ch = get_next_char(f);
		}
		else {
			ch = get_next_char();
		}

		/* Secretly keep count of the line numbers*/
		if( ch == '\n' ) {
			line_nr ++;
		}

		switch( state ) {
		  case ST_INITIAL:
			switch( ch ) {
			  case '\n':
			  case '\r':
			  case '\t':
			  case ' ':
				break;
			  case '#':
			  case ';':
			  case '=':
			  case ']':
				/* It's a comment or an error*/
				state = ST_IGNORE;
				break;
			  case '[':
				/* It's a section name*/
				state = ST_SECTIONNAME;
				sectionname[0] = 0;
				sectionname_pos = 0;
				break;
			  case 0:
				break;
			  default:
				/* It's a keyname*/
				state = ST_KEYNAME;
				keyname[0] = ch;
				keyname[1] = 0;
				keyname_pos = 1;
			}
			break;
		  case ST_IGNORE:
			switch( ch ) {
			  case '\n':
				state = ST_INITIAL;
				break;
			}
			break;
		  case ST_SECTIONNAME:
			switch( ch ) {
			  case '\n':
				report( RPT_WARNING, "Section name incorrectly closed on line %d of %s: %s", line_nr, source_descr, sectionname );
				state = ST_INITIAL;
				break;
			  case '\r':
			  case '\t':
			  case ' ':
			  case '"':
			  case '[':
				report( RPT_WARNING, "Section name contains invalid chars on line %d of %s: %s", line_nr, source_descr, sectionname );
				state = ST_INVALID_SECTIONNAME;
				break;
			  case ']':
				if( !( *current_section=find_section( sectionname ))) {
               				*current_section=add_section( sectionname );
				}
				state = ST_INITIAL;
				break;
			  case 0:
				report( RPT_WARNING, "Section name incorrectly closed on line %d of %s: %s", line_nr, source_descr, sectionname );
				break;
			  default:
				if( sectionname_pos<MAXSECTIONNAMELENGTH ) {
					sectionname[sectionname_pos++] = ch;
					sectionname[sectionname_pos] = 0;
				} else {
					report( RPT_WARNING, "Section name too long on line %d of %s: %s", line_nr, source_descr, sectionname );
					state = ST_INVALID_SECTIONNAME;
				}
			}
			break;
		  case ST_INVALID_SECTIONNAME:
			switch( ch ) {
			  case '\n':
			  case ']':
				state = ST_INITIAL;
				break;
			}
			break;
		  case ST_KEYNAME:
			switch( ch ) {
			  case 0:
			  case '\n':
			  case '\r':
			  case '\t':
			  case ' ':
				report( RPT_WARNING, "Loose word found on line %d of %s: %s", line_nr, source_descr, keyname );
				state = ST_INITIAL;
				break;
			  case '"':
			  case '[':
			  case ']':
				report( RPT_WARNING, "Key name contains invalid characters on line %d of %s: %s", line_nr, source_descr, keyname );
				state = ST_INVALID_KEYNAME;
				break;
			  case '=':
				state = ST_VALUE;
				value[0] = 0;
				value_pos = 0;
				break;
			  default:
				if( keyname_pos>=MAXKEYNAMELENGTH ) {
					report( RPT_WARNING, "Key name too long on line %d of %s: %s", line_nr, source_descr, keyname );
					state = ST_INVALID_KEYNAME;
				} else {
					keyname[keyname_pos++] = ch;
					keyname[keyname_pos] = 0;
				}
			}
			break;
		  case ST_INVALID_KEYNAME:
			switch( ch ) {
			  case '\n':
				state = ST_INITIAL;
			  /*case ' ':*/
			}
			break;
		  case ST_VALUE:
			switch( ch ) {
			  case '[':
			  case ']':
			  case '#':
			  case ';':
			  case '=':
				report( RPT_WARNING, "Value contains invalid characters on line %d of %s, at key: %s", line_nr, source_descr, keyname );
				state = ST_INVALID_VALUE;
				break;
			  case '"':
				state = ST_QUOTEDVALUE;
				break;
			  case 0:
			  case '\n':
			  case '\r':
			  case '\t':
			  case ' ':
				/* Value complete !*/
				if( ! *current_section ) {
					report( RPT_WARNING, "Data before any section on line %d of %s with key: %s", line_nr, source_descr, keyname );
				}
				else {
					/* Store the value*/
					k = add_key( *current_section, keyname, value );
				}
				/* And be ready for next thing...*/
				state = ST_INITIAL;
				break;
			  default:
				if( value_pos<MAXVALUELENGTH ) {
					value[value_pos++] = ch;
					value[value_pos] = 0;
				} else {
					report( RPT_WARNING, "Value key is too long on line %d of %s, at key: %s", line_nr, source_descr, keyname );
					state = ST_INVALID_KEYNAME;
				}
			}
			break;
		  case ST_INVALID_VALUE:
			switch( ch ) {
			  case '\n':
				state = ST_INITIAL;
				break;
			  case '"':
				state = ST_INVALID_QUOTEDVALUE;
			}
			break;
		  case ST_QUOTEDVALUE:
			switch( ch ) {
			  case 0:
			  case '\n':
				report( RPT_WARNING, "String is incorrectly terminated on line %d of %s: %s", line_nr, source_descr, keyname );
				state = ST_INITIAL;
				break;
			  case '\\':
				if( !quote ) {
					quote = 1;
					break;
				}
			  case '"':
				if( !quote ) {
					state = ST_VALUE;
					break;
				}
			  default:
				if( quote ) {
					switch( ch ) {
					  case 'n': ch = '\n'; break;
					  case 'r': ch = '\r'; break;
					  case 't': ch = '\t'; break;
					  /* default: litteral*/
					}
					quote = 0;
				}
				value[value_pos++] = ch;
				value[value_pos] = 0;
			}
			break;
		  case ST_INVALID_QUOTEDVALUE:
			switch( ch ) {
			  case '\n':
				state = ST_INITIAL;
				break;
			  case '"':
				state = ST_INVALID_VALUE;
			}
			break;
		}
		if( ch == 0 ) {
			state = ST_END;
		}
	}
	return 0;
}