#ifndef _TIME_H
#define _TIME_H

#include <stddef.h>
#include <sys/time.h>
#include <sys/types.h>

// Structure representing broken-down time.
struct tm
{
    int tm_sec;
    int tm_min;
    int tm_hour;
    int tm_mday;
    int tm_mon;
    int tm_year;
    int tm_wday;
    int tm_yday;
    int tm_isdst;
};

// Captures elapsed time with nanosecond precision.
struct timespec
{
    time_t tv_sec;
    long tv_nsec;
};

#define CLOCKS_PER_SEC 10000000 // Number of clock_t per second.

#define CLOCK_REALTIME 0
#define CLOCK_MONOTONIC 1
#define CLOCK_PROCTIME 2

#ifdef __cplusplus
extern "C"
{
#endif

    /* Returns a number representing how much CPU time has been used by this process. Divide this by CLOCKS_PER_SEC to
     * get the value in seconds. */
    clock_t clock(void);

    /* Returns the current UNIX time in seconds, which is also stored in tloc if it is nonnull. */
    time_t time(time_t* tloc);

    /* Retrieves precise time from a specific system clock. */
    int clock_gettime(clockid_t clock_id, struct timespec* tp);

    /* Converts the UNIX timestamp time to broken-down time in UTC. */
    struct tm* gmtime(const time_t* time);

    /* Converts the UNIX timestamp time to broken-down time in UTC. Thread-safe. */
    struct tm* gmtime_r(const time_t* time, struct tm* result);

    /* Converts the UNIX timestamp time to broken-down time in local time. */
    struct tm* localtime(const time_t* time);

    /* Converts the UNIX timestamp time to broken-down time in local time. Thread-safe. */
    struct tm* localtime_r(const time_t* time, struct tm* result);

    /* Returns a string representation of the broken-down time in the time structure. */
    char* asctime(const struct tm* time);

    /* Fills buf with the string representation of the broken-down time in the time structure. Thread-safe. */
    char* asctime_r(const struct tm* time, char buf[26]);

    /* Returns a string representation of time. */
    char* ctime(const time_t* time);

    /* Fills buf with a string representation of time. Thread-safe. */
    char* ctime_r(const time_t* time, char buf[26]);

    /* Returns the UNIX timestamp representation of the broken-down time in the time structure. */
    time_t mktime(struct tm* time);

    /* Fills str with a formatted string representation of time according to the format string. */
    size_t strftime(char* str, size_t max, const char* format, const struct tm* time);

    /* Returns the difference between two times. */
    double difftime(time_t time2, time_t time1);

#ifdef __cplusplus
}
#endif

#endif