// log.c  
#include "log.h"  
  
void log_message(LogLevel level, const char *format, ...) {  
    int log_fd = open("server.log", O_RDWR | O_CREAT | O_APPEND, 0666);  
    if (log_fd == -1) {  
        perror("open server.log");  
        return;  
    }  
  
    char log_buffer[2048];  
    time_t now;  
    struct tm *tm_info;  
    time(&now);  
    tm_info = localtime(&now);  
    strftime(log_buffer, sizeof(log_buffer), "[%Y-%m-%d %H:%M:%s]", tm_info);  
  
    const char *level_str;  
    switch (level) {  
        case LOG_LEVEL_INFO:  
            level_str = "INFO";  
            break;  
        case LOG_LEVEL_WARNING:  
            level_str = "WARNING";  
            break;  
        case LOG_LEVEL_ERROR:  
            level_str = "ERROR";  
            break;  
        default:  
            level_str = "UNKNOWN";  
            break;  
    }  
  
    strcat(log_buffer, " ");  
    strcat(log_buffer, level_str);  
    strcat(log_buffer, ": ");  
  
    va_list args;  
    va_start(args, format);  
    vsnprintf(log_buffer + strlen(log_buffer), sizeof(log_buffer) - strlen(log_buffer), format, args);  
    va_end(args);  
    strcat(log_buffer, "\n");  
  
    if (write(log_fd, log_buffer, strlen(log_buffer)) == -1) {  
        perror("write log file failed");  
    }  
  
    close(log_fd);  
}