#include <unistd.h>
#include <tlmplib.h>
#include <sys/time.h>
#include <fcntl.h>
#include <misc.h>
#include <vector>
#include <string>

using namespace std;

static int noproc = 0;

void fs_set_noproc (int _noproc)
{
	noproc = _noproc;
}
/*
	Create a uniq ID combining the process number of this instance, a random value and the time in micro-seconds
*/
string fs_makeid ()
{
	string ret;
	//char tmp[100];
	struct timeval t;
	if (gettimeofday(&t,NULL)!=-1){
		static int fd = -1;
		static bool error_shown = false;
		if (fd == -1){
			fd = open ("/dev/urandom",O_RDONLY,0);
		}
		if (fd == -1){
			if (!error_shown){
				tlmp_error ("Can't open /dev/urandom (%s)\n",strerror(errno));
				error_shown = true;
			}
		}else{
			struct {
				char buf[8];
				unsigned tv_sec;
				unsigned tv_usec;
			} data;
			data.tv_sec = t.tv_sec;
			data.tv_usec = t.tv_usec;
			//tlmp_error ("sizeof data=%lu %lu\n",sizeof(data),sizeof(data.tv_sec));
			if (read(fd,data.buf,8)!=8){
				close (fd);
				fd = -1;
				if (!error_shown){
					tlmp_error ("Can't read 8 bytes from /dev/urandom (%s)\n",strerror(errno));
					error_shown = true;
				}
			}else{
				#if 0
					for (int i=0; i<8; i++) snprintf (tmp+i*2,3,"%02x",buf[i]);
					int n = snprintf (tmp+16,sizeof(tmp)-16-1,"%08lx%08lx",t.tv_sec,t.tv_usec);
					snprintf (tmp+16+n,sizeof(tmp)-16-n-1,"-%d",noproc);
				#elif 0
					// Base64 is no good because it puts / in the result
					ret = base64_encode ((const char *)&data,17);	//sizeof(data));
				#else
					static const char *lk =
						"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
						"abcdefghijklmnopqrstuvwxyz"
						"0123456789_=";
					const unsigned char *pt = (unsigned char*)&data;
					char out[17*2];
					char *ptout = out;
					// tv_usec is an unsigned, but microseconds goes to 1,000,000.
					// So the mist significant byte is always 0.
					// So we processed only the first 15 bytes of the structure
					// and add noproc at the end.
					for (unsigned i=0; i<15; i+=3){
						// First 6 bits
						unsigned char byte = *pt++;
						unsigned byte64 = byte >>2;
						*ptout++ = lk[byte64];
						// Last 2 bits and 4 first bits of the next byte
						byte64 = (byte&3)<<4;
						byte = *pt++;
						byte64 |= byte >> 4;
						*ptout++ = lk[byte64];
						// Last 4 bits and 2 first bits of the next byte
						byte64 = (byte&15)<<2;
						byte = *pt++;
						byte64 |= (byte >> 6);
						*ptout++ = lk[byte64];
						// Last 6 bits of the byte
						byte64 = byte & 63;
						*ptout++ = lk[byte64];
					}
					*ptout++ = lk[noproc];
					*ptout = '\0';
					ret = out;
				#endif
			}
		}
	}
	return ret;
}