#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdarg.h>

FILE *logfile = NULL;
int loglevel;

#define LOG_FATAL 0
#define LOG_WARN 1
#define LOG_INFO 2
#define LOG_DEBUG 3

static void logit(int, const char *, va_list);

void
log_init(int level, int logstdout)
{
    char name[128];

    if (logstdout == 1) {
        logfile = stderr;
    } else {
        snprintf(name, sizeof(name), "pg.log");
        logfile = fopen(name, "a+");
        if (!logfile) {
            printf("cannot open log file %s!\n", name);
            exit(1);
        }
    }
    loglevel = level;
}

void
log_tmp(const char *msg, ...)
{
    va_list ap;

    va_start(ap, msg);
    vfprintf(logfile, msg, ap);
    fprintf(logfile, "\n");
    fflush(logfile);
    va_end(ap);
}
void
log_debug(const char *msg, ...)
{
    va_list ap;

    va_start(ap, msg);
    logit(LOG_DEBUG, msg, ap);
    va_end(ap);
}
void
log_info(const char *msg, ...)
{
    va_list ap;

    va_start(ap, msg);
    logit(LOG_INFO, msg, ap);
    va_end(ap);
}
void
log_warn(const char *msg, ...)
{
    va_list ap;

    va_start(ap, msg);
    logit(LOG_WARN, msg, ap);
    va_end(ap);
}
void
fatal(const char *msg, ...)
{
    va_list ap;

    va_start(ap, msg);
    logit(LOG_FATAL, msg, ap);
    va_end(ap);
    
    exit(1);
}

static void
logit(int level, const char *msg, va_list ap)
{
    time_t clock;
    char type;

    if (level <= loglevel) {
        switch (level) {
        case LOG_FATAL: type='X'; break;
        case LOG_WARN: type='W'; break;
        case LOG_INFO: type='.'; break;
        case LOG_DEBUG: type=' '; break;
        }
        time(&clock);
        fprintf(logfile, "%d %c ", (int)clock, type);
        vfprintf(logfile, msg, ap);
        fprintf(logfile, "\n");
        fflush(logfile);
    }
}