#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/file.h>
#include <signal.h>
#include <misc.h>
#include "userfirewall.m"
#include "userfirewall.h"
#include <openssl/sha.h>

static char misc_tohex(unsigned n)
{
	if (n >= 10){
		return n-10+'A';
	}else{
		return n+'0';
	}
}

/*
	Compute the SHA digest of a string and store it in hex form in res
*/
void misc_sha (
	const char *s,
	SSTRING &res)
{
	unsigned char tmp[SHA_DIGEST_LENGTH];
	SHA1 ((const unsigned char*)s,strlen(s),tmp);
	char tmphex[SHA_DIGEST_LENGTH*2+1];
	for (int i=0; i<SHA_DIGEST_LENGTH; i++){
		unsigned byte = tmp[i];
		tmphex[i*2] = misc_tohex(byte>>4);
		tmphex[i*2+1] = misc_tohex(byte&0xf);
	}
	tmphex[2*SHA_DIGEST_LENGTH] = '\0';
	res.setfrom (tmphex);
}

static const char *statefile = "/var/run/userfirewall.state";
static const char *statefile_tmp = "/var/run/userfirewall.state-TMP";
static const char *lockfile = "/var/run/userfirewall.lock";
static FILE *f_lock=NULL;

int misc_lock()
{
	int ret = -1;
	f_lock = fopen (lockfile,"w");
	if (f_lock != NULL){
		ret = flock(fileno(f_lock),LOCK_EX);
		if (ret == -1) misc_unlock();
	}
	return ret;
}
int misc_unlock()
{
	if (f_lock != NULL){
		fclose (f_lock);
		f_lock = NULL;
	}
	return 0;
}

/*
	Update, delete or add a record.
	The state file maintains a reference count for logins. So multiple
	logins must be undone by multiple logouts.

	This function is called both by login(addcnt=1) and logout (addcnt=-1)

	This function returns
		-1 if any error while updating
		 0 no record changed
		 1 one record changed, but only the reference count
		 2 The content of a record change, or a record was deleted or added
*/

static int misc_update(
	int addcnt,				
	const char *logid,
	const char *logip,
	const char *loggroups)
{
	int ret = -1;
	if (misc_lock()!=-1){
		FILE *fout = fopen (statefile_tmp,"w");
		if (fout != NULL){
			FILE *fin = fopen (statefile,"r");
			ret = 0;
			if (fin != NULL){
				char line[1000];
				bool anyuser = strcmp(logid,"-")==0;
				bool anyip = strcmp(logip,"-")==0;
				while (fgets(line,sizeof(line)-1,fin)!=NULL){
					strip_end (line);
					char id[100],ip[100];
					const char *pt = str_copyword (id,line);
					pt = str_copyword (ip,pt);
					pt = str_skip(pt);
					int count = atoi(pt);
					pt = str_skipdig(pt);
					const char *groups = str_skip(pt);
					if (count > 0){
						if ((strcmp(logid,id)!=0 && !anyuser)
							|| (strcmp(logip,ip)!=0 && !anyip)){
							fprintf (fout,"%s\n",line);
						}else{
							// Ok we have a match
							count += addcnt;
							if (count > 0){
								if (addcnt > 0){
									ret = strcmp(loggroups,groups)==0
										? 1 : 2;
									fprintf (fout,"%s\t%s\t%d\t%s\n"
										,id,ip,count,loggroups);
								}else{
									fprintf (fout,"%s\t%s\t%d\t%s\n"
										,id,ip,count,groups);
									ret = 1;
								}
							}else{
								// Record is deleted
								ret = 2;
							}
						}
					}
				}
				fclose (fin);
			}
			if (ret == 0 && addcnt > 0){
				fprintf (fout,"%s\t%s\t%d\t%s\n"
					,logid,logip,addcnt,loggroups);
				ret = 2;
			}
			fclose (fout);
			rename (statefile_tmp,statefile);
		}
		misc_unlock();
	}
	return ret;
}

int misc_logout(const char *logid, const char *logip)
{
	return misc_update (-1,logid,logip,"");
}


int misc_login (
	const char *id,
	const char *ip,
	const char *groups)
{
	return misc_update (1,id,ip,groups);
	#if 0
	misc_logout ("-",ip);
	if (misc_lock()!=-1){
		FILE *fout = fopen (statefile,"a");
		if (fout == NULL){
			xconf_error (MSG_U(E_OPENSTATE,"Can't update state file"));
		}else{
			fprintf (fout,"%s\t%s\t%s\n",id,ip,groups);
			fclose (fout);
		}
		misc_unlock();
	}
	#endif
}



/*
	A little line str_splitline, except that the delimitor occurs once
	at the end of a field. So if two delimiter occurs together, this
	means an empty field.
*/
int misc_splitline( const char *line, const char delim, SSTRINGS &tb)
{
	int ret = 0;
	while (*line != '\0'){
		const char *start = line;
		while (*line != '\0' && *line != delim) line++;
		SSTRING *s = new SSTRING;
		int len = (int)(line-start);
		if (len > 0) s->setfrom (start,len);
		ret++;
		tb.add (s);
		if (*line == delim){
			line++;
			if (*line == '\0'){
				tb.add (new SSTRING);
				ret++;
			}
		}
	}
	return ret;
}