timer-deque-rs 0.8.0

/*-
 * timer-deque-rs - a Rust crate which provides timer and timer queues based on target OS
 *  functionality.
 * 
 * Copyright (C) 2025 Aleksandr Morozov alex@nixd.org
 *  4neko.org alex@4neko.org
 * 
 * The timer-rs crate can be redistributed and/or modified
 * under the terms of either of the following licenses:
 *
 *   1. the Mozilla Public License Version 2.0 (the “MPL”) OR
 *                     
 *   2. The MIT License (MIT)
 *                     
 *   3. EUROPEAN UNION PUBLIC LICENCE v. 1.2 EUPL © the European Union 2007, 2016
 */



use std::{borrow::{Borrow, Cow}, cmp::Ordering, fmt, io::{self}, ops::{self, Deref}, sync::Arc, task::Poll, time::Duration};

use chrono::{DateTime, TimeZone};

use crate::{common, timer_portable::{portable_error::TimerPortResult}};


#[cfg(target_family = "unix")]
use super::unix::TimerFdInternal;


#[cfg(target_family = "windows")]
use super::windows::timer_fd_windows::TimerFdInternal;

use super::{timespec, TimerSetTimeFlags, UnixFd, TimerType, TimerFlags};

/// A super trait which defines a standart interface for the different time types i.e
/// 
/// - [RelativeTime] a relative time to the system's clock.
/// 
/// - [AbsoluteTime] an absolute time to the systmem's clock.
/// 
/// This is an internal trait and should not be exposed to the outside of the crate.
/// 
/// ## Traits
/// 
/// * [From<timespec>] - creates new instance from the two components: seconds and 
///     subnanoseconds of the seconds.
/// 
/// * [PartialEq] - comares the instances
/// 
/// * [PartialOrd] - ordering for sorting which compares both sec and nsec
/// 
/// * [fmt::Display] - displays the content in human readable format.
pub trait ModeTimeType: 
    Eq + PartialEq + Ord + PartialOrd + fmt::Display + fmt::Debug + Clone + Copy +
    From<timespec> + fmt::Display
{
    /// Returns the seconds without the nanoseconds fraction.
    fn get_sec(&self) -> i64;

    /// Returns the nanoseconds fraction from seconds, not a full time in nanoseconds.
    fn get_nsec(&self) -> i64;

    /// Verifies that the timer is not set to zero. For the [RelativeTime] it always returns true.
    fn is_value_valid(&self) -> bool;

    /// Returns the [TimerSetTimeFlags] which are autoinitialized for both types. This flags
    /// should be passed to timer.
    fn get_flags() -> TimerSetTimeFlags;
}

/// A `relative` time i.e time which is not binded to the system's clock.
/// 
/// ## Implementations
/// 
/// ```ignore
///     RelativeTime::from(Duration::from_sec(1));
/// ```
/// 
/// ```ignore
///     RelativeTime::from(10);
/// ```
/// 
/// ```ignore
///     RelativeTime::from((10, 46000));
/// ```
/// 
/// ```ignore
///     RelativeTime::new_time(10, 46000);
/// ```
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub struct RelativeTime
{
    /// Seconds
    time_sec: i64,

    /// A fraction of ns from second
    time_nsec: i64,
}

/// Converts the [Duration] to [RelativeTime] taking the `subsec_nanos`
/// for the `time_nsec`.
impl From<Duration> for RelativeTime
{
    fn from(value: Duration) -> Self 
    {
        return Self
        {
            time_sec: 
                value.as_secs() as i64,
            time_nsec: 
                value.subsec_nanos() as i64,
        };
    }
}

/// Converts the [i64] (seconds) to [RelativeTime] ignoring
/// the `subsec_nanos` fraction and setting it to zero.
impl From<i64> for RelativeTime
{
    fn from(value: i64) -> Self 
    {
        return 
            Self
            {
                time_sec: 
                    value,
                time_nsec: 
                    0
            };
    }
}

/// Converts the [u64] (seconds) to [RelativeTime] ignoring
/// the `subsec_nanos` fraction and setting it to zero.
impl From<u64> for RelativeTime
{
    fn from(value: u64) -> Self 
    {
        return 
            Self
            {
                time_sec: 
                    value as i64,
                time_nsec: 
                    0
            };
    }
}

/// Converts the tuple (i64, i64) (seconds, nsec) to [RelativeTime] ignoring
/// the `subsec_nanos` fraction and setting it to zero.
impl From<(i64, i64)> for RelativeTime
{
    fn from(value: (i64, i64)) -> Self 
    {
        return 
            Self
            {
                time_sec: 
                    value.0,
                time_nsec: 
                    value.1
            };
    }
}

/// Converts the [u128] (MSB:seconds|LSB:nanosec) to [RelativeTime] by 
/// separationg MSB seconds from nanoseconds
impl From<u128> for RelativeTime
{
    fn from(value: u128) -> Self 
    {
        // this is faster, but unsafe 
        //return unsafe { std::mem::transmute(value) };

        return 
            Self
            {
                time_sec: 
                    ((value & 0xFFFF_FFFF_FFFF_FFFF_0000_0000_0000_0000) >> 64) as i64,
                time_nsec: 
                    (value & 0x0000_0000_0000_0000_FFFF_FFFF_FFFF_FFFF) as i64
            };
    }
}


impl From<RelativeTime> for Duration
{
    fn from(value: RelativeTime) -> Self 
    {
        return Duration::new(value.time_sec as u64, value.time_nsec as u32);
    }
}

impl Ord for RelativeTime
{
    fn cmp(&self, other: &Self) -> Ordering 
    {
        return 
            self
                .time_sec
                .cmp(&other.time_sec)
                .then(
                    self
                        .time_nsec
                        .cmp(&other.time_nsec)
                );
    }
}

impl PartialOrd for RelativeTime
{
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> 
    {
        return Some(self.cmp(other));
    }
}

impl fmt::Display for RelativeTime
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result 
    {
        write!(f, "[relative] sec: {}, nsec: {}", self.time_sec, self.time_nsec)
    }
}



impl ModeTimeType for RelativeTime
{
    fn get_sec(&self) -> i64 
    {
        return self.time_sec;
    }
    
    fn get_nsec(&self) -> i64 
    {
        return self.time_nsec;
    }

    fn is_value_valid(&self) -> bool 
    {
        return true;    
    }

    fn get_flags() -> TimerSetTimeFlags
    {
        return TimerSetTimeFlags::empty();
    }
}

impl RelativeTime
{
    /// max nanoseconds
    pub const MAX_NS: i64 = 1_000_000_000;

    /// Creates new instance for relative time accepting the user input.
    /// 
    /// Automatically corrects the `time_nsec` value if it is larger than
    /// 999_999_999ns.
    /// 
    /// # Arguments
    /// 
    /// `time_sec` - [i64] a seconds in relative notation.
    /// 
    /// `time_nsec` - [i64] nanoseconds of relative seconds value. Should not be 
    ///     larger than 999_999_999 which is defined by const [Self::MAX_NS]. In
    ///     case if it is larger, the `nsec` will be rounded and an extra secons
    ///     will be added.
    pub 
    fn new_time(time_sec: i64, time_nsec: i64) -> Self
    {
        let extra_sec = time_nsec / Self::MAX_NS;
        let nsec_new = time_nsec % Self::MAX_NS;

        return 
            Self
            { 
                time_nsec: nsec_new, 
                time_sec: time_sec + extra_sec,
            };
    }

    pub 
    fn is_zero(&self) -> bool
    {
        return self.time_nsec == 0 && self.time_sec == 0;
    } 
}

/// An `absolute` time which are binded to the system's clock
/// and never be zero except when timer is reset.
/// 
/// ## Implementations
/// 
/// ```ignore
///     AbsoluteTime::from(LocalTime::now());
/// ```
/// 
/// ```ignore
///     AbsoluteTime::from(Duration::from_sec(1));
/// ```
/// 
/// ```ignore
///     AbsoluteTime::from(10);
/// ```
/// 
/// ```ignore
///     AbsoluteTime::from((10, 46000));
/// ```
/// 
/// ```ignore
///     AbsoluteTime::new_time(10, 46000);
/// ```
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub struct AbsoluteTime
{
    /// A full seconds.
    time_sec: i64,

    /// A fraction (subset) of nanoseconds from the second.
    time_nsec: i64,
}

/// Convers the `chrono` [DateTime<TZ>] into the [AbsoluteTime] using 
/// the `TZ` [TimeZone]  taking the `ns` fraction of a second (subsec_nano) 
/// using `timestamp_subsec_nanos` function.
impl<TZ: TimeZone> From<DateTime<TZ>> for AbsoluteTime
{
    fn from(value: DateTime<TZ>) -> Self 
    {
        return 
            Self
            {
                time_sec: 
                    value.timestamp(), 
                time_nsec: 
                    value.timestamp_subsec_nanos() as i64,
            };
    }
}

/// Converts the [Duration] to [AbsoluteTime] taking the `subsec_nanos`
/// for the `time_nsec`.
impl From<Duration> for AbsoluteTime
{
    fn from(value: Duration) -> Self 
    {
        return 
            Self
            {
                time_sec: 
                    value.as_secs() as i64,
                time_nsec: 
                    value.subsec_nanos() as i64,
            };
    }
}

/// Converts the [i64] (seconds) to [AbsoluteTime] ignoring
/// the `subsec_nanos` fraction and setting it to zero.
impl From<i64> for AbsoluteTime
{
    fn from(value: i64) -> Self 
    {
        return 
            Self
            {
                time_sec: 
                    value,
                time_nsec: 
                    0
            };
    }
}

/// Converts the [u64] (seconds) to [AbsoluteTime] ignoring
/// the `subsec_nanos` fraction and setting it to zero.
impl From<u64> for AbsoluteTime
{
    fn from(value: u64) -> Self 
    {
        return 
            Self
            {
                time_sec: 
                    value as i64,
                time_nsec: 
                    0
            };
    }
}

/// Converts the tuple (i64, i64) (seconds, nsec) to [AbsoluteTime] ignoring
/// the `subsec_nanos` fraction and setting it to zero.
impl From<(i64, i64)> for AbsoluteTime
{
    fn from(value: (i64, i64)) -> Self 
    {
        return 
            Self
            {
                time_sec: 
                    value.0,
                time_nsec: 
                    value.1
            };
    }
}

/// Converts the [u128] (MSB:seconds|LSB:nanosec) to [AbsoluteTime] by 
/// separationg MSB seconds from nanoseconds
impl From<u128> for AbsoluteTime
{
    fn from(value: u128) -> Self 
    {
        // this is faster, but unsafe 
        //return unsafe { std::mem::transmute(value) };

        return 
            Self
            {
                time_sec: 
                    ((value & 0xFFFF_FFFF_FFFF_FFFF_0000_0000_0000_0000) >> 64) as i64,
                time_nsec: 
                    (value & 0x0000_0000_0000_0000_FFFF_FFFF_FFFF_FFFF) as i64
            };
    }
}

impl From<AbsoluteTime> for Duration
{
    fn from(value: AbsoluteTime) -> Self 
    {
        return Duration::new(value.time_sec as u64, value.time_nsec as u32);
    }
}

impl Ord for AbsoluteTime
{
    fn cmp(&self, other: &Self) -> Ordering 
    {
        return 
            self
                .time_sec
                .cmp(&other.time_sec)
                .then(
                    self
                        .time_nsec
                        .cmp(&other.time_nsec)
                );
    }
}

impl PartialOrd for AbsoluteTime
{
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> 
    {
        return Some(self.cmp(other));
    }
}

impl ops::AddAssign<Duration> for AbsoluteTime
{
    fn add_assign(&mut self, rhs: Duration) 
    {
        self.time_nsec += rhs.subsec_nanos() as i64;
        let add_sec = self.time_nsec / Self::MAX_NS;

        if add_sec > 0
        {
            self.time_nsec %=  Self::MAX_NS;
        }
        
        self.time_sec += rhs.as_secs() as i64 + add_sec;
    }
}

impl ops::AddAssign<RelativeTime> for AbsoluteTime
{
    fn add_assign(&mut self, rhs: RelativeTime) 
    {
        self.time_nsec += rhs.time_nsec;
        let add_sec = self.time_nsec / Self::MAX_NS;

        if add_sec > 0
        {
            self.time_nsec %=  Self::MAX_NS;
        }
        
        self.time_sec += rhs.time_sec + add_sec;
    }
}

impl ops::Add<Duration> for AbsoluteTime
{
    type Output = AbsoluteTime;

    fn add(mut self, rhs: Duration) -> Self::Output 
    {
        self += rhs;

        return self;
    }
}

impl ops::Add<RelativeTime> for AbsoluteTime
{
    type Output = AbsoluteTime;

    fn add(mut self, rhs: RelativeTime) -> Self::Output 
    {
        self += rhs;

        return self;
    }
}

impl ops::SubAssign<Duration> for AbsoluteTime
{
    fn sub_assign(&mut self, rhs: Duration) 
    {
        let mut sec = rhs.as_secs() as i64;
        let mut nsec = self.time_nsec - rhs.subsec_nanos() as i64;

        if nsec < 0
        {
            sec += 1;

            nsec = Self::MAX_NS + nsec;
        }
        
        self.time_nsec = nsec;
        self.time_sec -= sec;

        return;
    }
}

impl ops::SubAssign<RelativeTime> for AbsoluteTime
{
    fn sub_assign(&mut self, mut rhs: RelativeTime) 
    {

        let mut nsec = self.time_nsec - rhs.time_nsec;

        if nsec < 0
        {
            rhs.time_sec += 1;

            nsec = Self::MAX_NS + nsec;
        }
        
        self.time_nsec = nsec;
        self.time_sec -= rhs.time_sec;

        return;
    }
}

impl ops::Sub<Duration> for AbsoluteTime
{
    type Output = AbsoluteTime;

    fn sub(mut self, rhs: Duration) -> Self::Output 
    {
        self -= rhs;

        return self;
    }
}

impl ops::Sub<RelativeTime> for AbsoluteTime
{
    type Output = AbsoluteTime;

    fn sub(mut self, rhs: RelativeTime) -> Self::Output 
    {
        self -= rhs;

        return self;
    }
}

impl ops::SubAssign for AbsoluteTime
{
    fn sub_assign(&mut self, mut rhs: Self) 
    {

        let mut nsec = self.time_nsec - rhs.time_nsec;

        if nsec < 0
        {
            rhs.time_sec += 1;

            nsec = Self::MAX_NS + nsec;
        }
        
        self.time_nsec = nsec;
        self.time_sec -= rhs.time_sec;

        return;
    }
}

impl ops::Sub for AbsoluteTime
{
    type Output = AbsoluteTime;

    fn sub(mut self, rhs: Self) -> Self::Output 
    {
        self -= rhs;

        return self;
    }
}


impl fmt::Display for AbsoluteTime
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result 
    {
        write!(f, "[absolute] {}.{:09}sec", self.time_sec, self.time_nsec)
    }
}



impl ModeTimeType for AbsoluteTime
{
    fn get_sec(&self) -> i64 
    {
        return self.time_sec;
    }
    
    fn get_nsec(&self) -> i64 
    {
        return self.time_nsec;
    }

    fn is_value_valid(&self) -> bool 
    {
        return self.time_nsec != 0 || self.time_sec != 0;
    }

    fn get_flags() -> TimerSetTimeFlags
    {
        return TimerSetTimeFlags::TFD_TIMER_ABSTIME | TimerSetTimeFlags::TFD_TIMER_CANCEL_ON_SET;
    }
}

impl AbsoluteTime
{
    /// max nanoseconds
    pub const MAX_NS: i64 = 1_000_000_000;//999_999_999;
}

impl AbsoluteTime
{
    /// Creates an instance with the current local time.
    pub 
    fn now() -> Self
    {
        let value = common::get_current_timestamp();

        return Self
        {
            time_sec: value.timestamp(), 
            time_nsec: value.timestamp_subsec_nanos() as i64,
        }
    }

    pub 
    fn new_time(time_sec: i64, time_nsec: i64) -> Option<Self>
    {
        let tm = 
            unsafe { Self::new_time_unchecked(time_sec, time_nsec) };

        if tm.is_value_valid() == false
        {
            return None;
        }

        return Some(tm);
    }

    /// Creates new instance for absolute time accepting the user input.
    /// 
    /// Automatically corrects the `time_nsec` value if it is larger than
    /// 999_999_999ns.
    /// 
    /// # Arguments
    /// 
    /// `time_sec` - [i64] a seconds in absolute notation.
    /// 
    /// `time_nsec` - [i64] nanoseconds of absolute seconds value. Should not be 
    ///     larger than 999_999_999 which is defined by const [Self::MAX_NS]. In
    ///     case if it is larger, the `nsec` will be rounded and an extra secons
    ///     will be added.
    /// 
    /// # Returns 
    /// 
    /// An instance is returned. May panic on overflow.
    pub unsafe 
    fn new_time_unchecked(time_sec: i64, time_nsec: i64) -> Self
    {
        let extra_sec = time_nsec / Self::MAX_NS;
        let nsec_new = time_nsec % Self::MAX_NS;

        return 
            Self
            { 
                time_nsec: nsec_new, 
                time_sec: time_sec + extra_sec,
            };
    }

    /// Compares only full seconds without nanoseconds fraction (subnano).
    pub 
    fn seconds_cmp(&self, other: &Self) -> Ordering
    {
        return self.time_sec.cmp(&other.time_sec);
    }

    pub 
    fn add_sec(mut self, seconds: i64) -> Self
    {
        self.time_sec += seconds;

        return self;
    }

    pub 
    fn reset_nsec(mut self) -> Self
    {
        self.time_nsec = 0;

        return self;
    }
}


/// A timer expiry modes. Not every OS supports 
/// every mode. Read comments for the OS specific
/// timer. For the `nanoseconds` param the max value
/// is 999_999_999 for most OSes.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum TimerExpMode<TIMERTYPE: ModeTimeType>
{
    /// Disarmed
    None, 

    /// A timer which is triggered once.
    OneShot
    {
        timeout: TIMERTYPE
    },
    
    /// Interval with the initial delay.
    IntervalDelayed
    {
        /// First event delay.
        delay_tm: TIMERTYPE,

        /// Interval.
        interv_tm: TIMERTYPE
    },

    /// Interval, with the first timeout event 
    /// equal to interval values.
    Interval
    {
        /// Interval seconds.
        interv_tm: TIMERTYPE
    },
}


impl ops::AddAssign<RelativeTime> for TimerExpMode<AbsoluteTime>
{
    fn add_assign(&mut self, rhs: RelativeTime) 
    {
        match self
        {
            TimerExpMode::None => 
                return,
            TimerExpMode::OneShot { timeout } => 
            {
                *timeout += rhs;
                
            },
            TimerExpMode::IntervalDelayed { interv_tm, .. } => 
            {
                *interv_tm += rhs;
            },
            TimerExpMode::Interval { interv_tm } => 
            {
               *interv_tm += rhs;
            },
        }
    }
}


impl ops::Add<RelativeTime> for TimerExpMode<AbsoluteTime>
{
    type Output = TimerExpMode<AbsoluteTime>;

    fn add(mut self, rhs: RelativeTime) -> Self::Output 
    {
        self += rhs;

        return self;
    }
}


impl<TIMERTYPE: ModeTimeType> Ord for TimerExpMode<TIMERTYPE>
{
    fn cmp(&self, other: &Self) -> Ordering 
    {
        match (self, other)
        {
            (TimerExpMode::None, TimerExpMode::None) => 
                return Ordering::Equal,
            (TimerExpMode::OneShot{ timeout }, TimerExpMode::OneShot { timeout: timeout2 }) => 
            { 
                return timeout.cmp(timeout2);
            },
            (
                TimerExpMode::IntervalDelayed{ delay_tm, interv_tm }, 
                TimerExpMode::IntervalDelayed{ delay_tm: delay_tm2, interv_tm: interv_tm2 }
            ) =>
            {
                return 
                    delay_tm.cmp(delay_tm2)
                        .then(interv_tm.cmp(interv_tm2));
            },
            (TimerExpMode::Interval { interv_tm }, TimerExpMode::Interval { interv_tm: interv_tm2 }) => 
            {
                return interv_tm.cmp(interv_tm2);
            },
            _ => 
                panic!("cannot compare different types {} and {}", self, other)
        }
    }
}

impl<TIMERTYPE: ModeTimeType> PartialOrd for TimerExpMode<TIMERTYPE>
{
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> 
    {
        return Some(self.cmp(other));
    }
}



/// Implementations of the [TimerExpMode] for [AbsoluteTime].
impl TimerExpMode<AbsoluteTime>
{
    /// Checks value for the `set_time` function. To disarm timer 
    /// use `unset_time`.
    #[inline]
    fn is_valid_inner(&self) -> bool
    {
        match self
        {
            Self::None => 
                return false,
            Self::OneShot{ timeout} => 
                return timeout.is_value_valid(),
            Self::IntervalDelayed{ delay_tm, interv_tm } => 
                return delay_tm.is_value_valid() && interv_tm.is_value_valid(),
            Self::Interval{ interv_tm } => 
                return interv_tm.is_value_valid()
        }
    }

    /// Construct the [TimerExpMode::OneShot] timer. For the `absolute` timer
    /// only this type is available. The [AbsoluteTime] should be provided which
    /// should be ahead of the OS'es timer.
    pub 
    fn new_oneshot(abs_time: impl Into<AbsoluteTime>) -> Self
    {
        return Self::OneShot { timeout: abs_time.into() };
    }
}



/// Implementations of the [TimerExpMode] for [RelativeTime].
impl TimerExpMode<RelativeTime>
{
    /// Construct the [TimerExpMode::OneShot] timer. A [RelativeTime] should 
    /// be provided as argument. This type of timer is triggered only once.
    pub 
    fn new_oneshot(rel_time: impl Into<RelativeTime>) -> Self
    {
        return Self::OneShot { timeout: rel_time.into() };
    }

    /// Constrcut the [TimerExpMode::Interval] timer. A [RelativeTime] should 
    /// be provided as agument which specifies the trigger interval.
    pub 
    fn new_interval(rel_time: impl Into<RelativeTime>) -> Self
    {
        return Self::Interval { interv_tm: rel_time.into() };
    }

    /// Construct the [TimerExpMode::IntervalDelayed] timer. A two [RelativeTime] 
    /// arguments should be provided which would set the initial delay and further
    /// interval. The initial delay happens only once. Then the interval will be used.
    /// If `delay_time` and `intev_time` are same, acts as `new_interval`.
    pub 
    fn new_interval_with_init_delay(delay_time: impl Into<RelativeTime>, intev_time: impl Into<RelativeTime>) -> Self
    {
        return Self::IntervalDelayed { delay_tm: delay_time.into(), interv_tm: intev_time.into() };
    }
}

impl<TIMERTYPE: ModeTimeType> TimerExpMode<TIMERTYPE>
{
    /// Disarms the timer.
    #[inline]
    pub 
    fn reset() -> Self
    {
        return Self::None;
    }
}

impl<TIMERTYPE: ModeTimeType> fmt::Display for TimerExpMode<TIMERTYPE>
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result 
    {
        match self
        {
            Self::None => 
                write!(f, "disarmed"),
            Self::OneShot{ timeout } => 
                write!(f, "oneshot {}", timeout),
            Self::IntervalDelayed
                { delay_tm, interv_tm } => 
                write!(f, "interval {} with delay {}", interv_tm, delay_tm),
            Self::Interval{ interv_tm } => 
                write!(f, "interval {}", interv_tm),
        }
    }
}



/*
#[cfg(target_os = "macos")]
#[repr(C)]
pub struct timespec 
{
    pub tv_sec: libc::time_t,
    pub tv_nsec: libc::c_long,
}
#[cfg(target_os = "macos")]
#[repr(C)]
pub struct itimerspec 
{
    pub it_interval: timespec,
    pub it_value: timespec,
}
    */

/// A timer FD read operation result.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum TimerReadRes<T: Sized + fmt::Debug + fmt::Display + Clone + Eq + PartialEq>
{
    /// Read successfull.
    Ok(T),

    /// TFD_TIMER_ABSTIME 
    /// > Marks this timer as cancelable if the real-time clock  under‐
    /// > goes  a  discontinuous change (settimeofday(2), clock_settime(2),
    /// > or similar).  When  such  changes  occur,  a  current  or  future
    /// > read(2)  from  the file descriptor will fail with the error 
    /// > ECANCELED.
    /// 
    /// This is not appliciable for `Kqeueue` BSD timer and `Windows`.
    Cancelled,

    /// EAGAIN
    /// If FD is nonblocking then this will be returned.
    WouldBlock,
}

impl TimerReadRes<u64>
{
    pub 
    fn ok() -> Self
    {
        return Self::Ok(1);
    }
}


impl<T: Sized + fmt::Debug + fmt::Display + Clone + Eq + PartialEq> fmt::Display for TimerReadRes<T>
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result 
    {
        match self
        {
            Self::Ok(ovfl) => 
                write!(f, "OK(overflows:{})", ovfl),
            Self::Cancelled => 
                write!(f, "CANCELLED"),
            Self::WouldBlock => 
                write!(f, "WOULDBLOCK"),
        }
    }
}

impl<T: Sized + fmt::Debug + fmt::Display + Clone + Eq + PartialEq> TimerReadRes<T>
{
    pub 
    fn unwrap(self) -> T
    {
        let Self::Ok(t) = self
        else { panic!("can not unwrap {:?}", self)};

        return t;
    }
}

/// A tarit which implements standart interface for the MIO crate.
#[cfg(all(target_family = "unix", feature = "enable_mio_compat"))]
pub trait TimerFdMioCompat: mio::event::Source + PartialEq<mio::Token>
{
    /// Gets the event identification token. It is a RawFd of the timer.
    fn get_token(&self) -> mio::Token;
}

/// A trait which provides a standart interface to aquire the [TimerId]
/// which is a unification of the timer instance identification.
/// 
/// # Implementations
/// 
/// A sub-trait of [FdTimerRead].
pub trait AsTimerId
{
    /// Returns the uniq timer ID number.
    fn as_timer_id(&self) -> TimerId;
}

/// A unified timer identification instance which can be used to identify
/// the timers.
#[repr(transparent)]
#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct TimerId(pub(crate) usize);


impl PartialEq<usize> for TimerId
{
    fn eq(&self, other: &usize) -> bool 
    {
        return self.0 == *other;
    }
}

impl fmt::Display for TimerId
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result 
    {
        write!(f, "{}", self.0)
    }
}

impl Borrow<usize> for TimerId
{
    fn borrow(&self) -> &usize 
    {
        return &self.0;
    }
}


/// A super trait which is used on timers for executing the reading code 
/// of the timer.
/// 
/// ## Traits
/// 
/// * [PartialEq<str>] - compares the timer by its name.
/// 
/// * [PartialEq<RawFd>] - comares the timer by its FD.
pub trait FdTimerRead: UnixFd + fmt::Display + AsRef<str> + PartialEq<str> + AsTimerId
{
    /// Attempts to read the timer. The realization is different on different OS. The main purpose 
    /// is to check if timer is ready (ended).
    /// 
    /// # Returns
    /// 
    /// * If FD is configured as non-blocking then returns 
    ///     [TimerReadRes::WouldBlock] otherwise would block.
    /// 
    /// * If daytime modification happened the 
    ///     [TimerReadRes::Cancelled] will be returned, however
    ///     it depends if the [TimerSetTimeFlags::TFD_TIMER_CANCEL_ON_SET]
    ///     is set with [TimerSetTimeFlags::TFD_TIMER_ABSTIME]. Does not
    ///     work on KQueue implementation.
    /// 
    /// * If read was successfull the amount of the overflows before
    ///     read will be returned i.e [TimerReadRes::Ok]. 
    ///     Normally is is `1`. If `0` is returned then probably the
    ///     time or day was modified.
    /// 
    /// * The [Result::Err] is returned if other error occured.
    fn read(&self) -> TimerPortResult<TimerReadRes<u64>>;
}

/// A super trait which implements a marker for the `timer poll` subsystem.
/// 
/// ## Traits
/// 
/// * [FdTimerRead] - a sub trait which is a super trait which includes user
///     sub-traits.
pub trait FdTimerMarker: FdTimerRead + Eq + PartialEq
{
    /// Clones the instance of the timer.
    fn clone_timer(&self) -> TimerFd;

    /// Returns the count of strong references to inner type.
    fn get_strong_count(&self) -> usize;
}


/// A common trait which is implemented by all timer realizationss for different OSes.
pub trait FdTimerCom: FdTimerRead
{
    /// Creates new isntance of the timer.
    /// 
    /// # Arguments
    /// 
    /// * `label` - a [Cow] string which defines a title of the timer for identification.
    /// 
    /// * `timer_type` - a [TimerType] a clock source
    /// 
    /// * `timer_flags` - a [TimerFlags] configuration of the timer's FD.
    /// 
    /// # Returns
    /// 
    /// A [Result] is retuned with instance on success.
    fn new(label: Cow<'static, str>, timer_type: TimerType, timer_flags: TimerFlags) -> TimerPortResult<Self>
    where Self: Sized;

    /// Sets the timer. The timer starts immidiatly and working depending on the `timer_exp` mode.
    /// 
    /// In case of timer does not support [TimerExpMode::IntervalDelayed] nativly (on OS level), the
    /// crate will store the `interval` part and set interval on first `read()` i.e after the `delay`
    /// and remove the stored `interval` (or may not) from the inner field.
    fn set_time<TIMERTYPE: ModeTimeType>(&self, timer_exp: TimerExpMode<TIMERTYPE>) -> TimerPortResult<()>;

    /// Unsets the timer. The timer stops immidiatly.
    fn unset_time(&self) -> TimerPortResult<()>;

    /// Sets the timer to non-blocking (on case if `flag` is `true`). 
    /// If the timer was inited with
    /// [TimerFlags::TFD_NONBLOCK], then this will not do anything. 
    fn set_nonblocking(&self, flag: bool) -> TimerPortResult<()>;

    /// Reads the FD's flags and check if Fd is in non-blocking mode. 
    /// May return error.
    /// 
    /// # Returns
    /// 
    /// * `true` - FD is non-blocking
    /// 
    /// * `false` - FD is blocking
    fn is_nonblocking(&self) -> TimerPortResult<bool>;
}

/// A common abstract type for the timer which is a main instance.
/// 
/// ## Implements
/// 
/// This instance implements:
/// 
/// * [fmt::Display], [AsRawFd], [AsFd], [AsRef], [Eq], [PartialEq], [Deref]
/// 
/// * [FdTimerMarker], [FdTimerRead]
/// 
/// * [TimerFdMioCompat] and [mio::event::Source] - if the `feature = enable_mio_compat` is enabled.
/// 
/// ## Multithread
/// 
/// A MT-safe, read-only. MT-access is implemented on OS level, so no mutexes
/// or other sync is implemented.
/// 
/// ## Poll
/// 
/// - A built-in [crate::TimerPoll] can be used.
/// 
/// - An external crate MIO [TimerFdMioCompat] if `feature = enable_mio_compat` is
/// enabled.
/// 
/// - User implemented poll. The FD can be aquired via [AsRawFd] [AsFd].
/// 
/// ## Async
/// 
/// A [Future] is implemented.
/// 
/// ## Examples
/// 
/// ```ignore
/// let timer = 
///     TimerFd::new(Cow::Borrowed("test"), TimerType::CLOCK_REALTIME, 
///         TimerFlags::empty()).unwrap();
/// 
/// timer 
/// ```
#[repr(transparent)]
#[derive(Debug)]
pub struct TimerFd(Arc<TimerFdInternal>);

impl AsTimerId for TimerFd
{
    fn as_timer_id(&self) -> TimerId 
    {
        return self.0.as_timer_id();
    }
}

impl fmt::Display for TimerFd
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result 
    {
        write!(f, "{}", self.0)
    }
}


impl AsRef<str> for TimerFd
{
    fn as_ref(&self) -> &str 
    {
        return self.0.as_ref().as_ref();
    }
}

impl Eq for TimerFd {}

impl PartialEq for TimerFd
{
    fn eq(&self, other: &Self) -> bool 
    {
        return self.0 == other.0
    }
}

impl PartialEq<str> for TimerFd
{
    fn eq(&self, other: &str) -> bool 
    {
        return self.0.as_ref() == other;
    }
}

impl FdTimerMarker for TimerFd
{
    fn clone_timer(&self) -> TimerFd 
    {
        return Self(self.0.clone());
    }

    fn get_strong_count(&self) -> usize 
    {
        return Arc::strong_count(&self.0);
    }
}

/// Returns reference to the timer implementation.
impl Deref for TimerFd
{
    type Target = TimerFdInternal;

    fn deref(&self) -> &Self::Target 
    {
        return self.0.as_ref();
    }
}

impl Future for &TimerFd
{
    type Output = TimerPortResult<TimerReadRes<u64>>;

    fn poll(self: std::pin::Pin<&mut Self>, cx: &mut std::task::Context<'_>) -> std::task::Poll<Self::Output> 
    {
        let res = self.get_timer().read();

        if let Ok(TimerReadRes::WouldBlock) = res
        {
            cx.waker().wake_by_ref();

            return Poll::Pending;
        }
        else
        {
            return Poll::Ready(res);
        } 
    }
}

impl Future for TimerFd
{
    type Output = TimerPortResult<TimerReadRes<u64>>;

    fn poll(self: std::pin::Pin<&mut Self>, cx: &mut std::task::Context<'_>) -> std::task::Poll<Self::Output> 
    {
        let res = self.get_timer().read();

        if let Ok(TimerReadRes::WouldBlock) = res
        {
            cx.waker().wake_by_ref();

            return Poll::Pending;
        }
        else
        {
            return Poll::Ready(res);
        } 
    }
}

impl TimerFd
{
    pub 
    fn new(label: Cow<'static, str>, timer_type: TimerType, timer_flags: TimerFlags) -> TimerPortResult<Self>
    {
        return Ok(
            Self( Arc::new(TimerFdInternal::new(label, timer_type, timer_flags)?) )
        );
    }

    /// Borrows non-muntable reference to the timer. A [Deref] is implemented for this purpose,
    /// but the function was left for compat.
    pub 
    fn get_timer(&self) -> &TimerFdInternal
    {
        return &self.0;
    }
}

impl FdTimerRead for TimerFd
{
    fn read(&self) -> TimerPortResult<TimerReadRes<u64>> 
    {
        return self.0.read();
    }
}







#[cfg(test)]
mod tests
{

    use std::time::Duration;

    use crate::{common, timer_portable::timer::{AbsoluteTime, RelativeTime, TimerExpMode}};

    #[test]
    fn test_0() 
    {
        let ts = common::get_current_timestamp();

        let texp1 = TimerExpMode::<AbsoluteTime>::new_oneshot(AbsoluteTime::from(ts));

        assert_eq!(
            TimerExpMode::OneShot { timeout: AbsoluteTime::from(ts) },
            texp1
        );
        
    }

    #[test]
    fn test_1() 
    {
        let ts = common::get_current_timestamp();

        let texp1 = 
            TimerExpMode::<AbsoluteTime>::new_oneshot(AbsoluteTime::from(ts));

        let texp2 = 
            texp1 + RelativeTime::new_time(1, 0);

        assert_eq!(texp1 < texp2, true);
        assert_eq!(texp2 > texp1, true);
        assert_eq!(texp2 != texp1, true);
        assert_eq!(texp2 < texp1, false);
    }

    #[test]
    fn test_2() 
    {

        let texp1 = 
            TimerExpMode::<AbsoluteTime>::new_oneshot(
                unsafe {AbsoluteTime::new_time_unchecked(100, AbsoluteTime::MAX_NS)}
            );
       
        let texp2 = 
            texp1 + RelativeTime::new_time(0, 1);


        assert_eq!(texp1 < texp2, true);
        assert_eq!(texp2 > texp1, true);
        assert_eq!(texp2 != texp1, true);
        assert_eq!(texp2 < texp1, false);
    }

    #[test]
    fn test_timer_from_test() 
    {
        let abs1 = AbsoluteTime::from((100, 200));
        assert_eq!(abs1.time_sec, 100);
        assert_eq!(abs1.time_nsec, 200);

        let abs2 = AbsoluteTime::from(0x0000_0000_0000_00FF_0000_0000_0000_0AAA as u128);
        assert_eq!(abs2.time_sec, 0xFF);
        assert_eq!(abs2.time_nsec, 0xAAA);

        let abs3 = AbsoluteTime::from(400 as u64);
        assert_eq!(abs3.time_sec, 400);
        assert_eq!(abs3.time_nsec, 0);

        let abs4 = AbsoluteTime::from(Duration::new(456, 123456));
        assert_eq!(abs4.time_sec, 456);
        assert_eq!(abs4.time_nsec, 123456);
    }

    #[should_panic]
    #[test]
    fn test_2_fail() 
    {
        let ts = common::get_current_timestamp();

        let texp1 = 
            TimerExpMode::<AbsoluteTime>::new_oneshot(AbsoluteTime::from(ts));

        let texp2 = 
            TimerExpMode::<AbsoluteTime>::Interval { interv_tm:  AbsoluteTime::from(ts)};

        assert_eq!(texp1 == texp2, true);
    }

    #[test]
    fn test_abstime_cmp()
    {
        let abs_time = AbsoluteTime::now();
        let abs_time_future = abs_time + RelativeTime::new_time(10, 1);
        let abs_time_past = abs_time - RelativeTime::new_time(10, 1);

        assert_eq!(abs_time < abs_time_future, true);
        assert_eq!(abs_time_future > abs_time, true);
        assert_eq!(abs_time > abs_time_past, true);
        assert_eq!(abs_time_past < abs_time, true);
        assert_eq!(abs_time_future > abs_time_past, true);
        assert_eq!(abs_time_past < abs_time_future, true);
    }

    #[test]
    fn test_abstime_new()
    {
        let abs = AbsoluteTime::new_time(1, 999_999_999).unwrap();
        assert_eq!(abs.time_nsec, 999_999_999);
        assert_eq!(abs.time_sec, 1);

        let abs = AbsoluteTime::new_time(1, 1_000_000_000).unwrap();
        assert_eq!(abs.time_nsec, 0);
        assert_eq!(abs.time_sec, 2);

        let abs = AbsoluteTime::new_time(1, 1_000_000_001).unwrap();
        assert_eq!(abs.time_nsec, 1);
        assert_eq!(abs.time_sec, 2);

        let abs = AbsoluteTime::new_time(1, 2_000_000_001).unwrap();
        assert_eq!(abs.time_nsec, 1);
        assert_eq!(abs.time_sec, 3);
    }

    #[test]
    fn test_abstime_add()
    {
        let mut abs = AbsoluteTime::new_time(1, 999_999_999).unwrap();

        abs += RelativeTime::new_time(0, 1);

        assert_eq!(abs.time_nsec, 0);
        assert_eq!(abs.time_sec, 2);

        abs += RelativeTime::new_time(1, 1);

        assert_eq!(abs.time_nsec, 1);
        assert_eq!(abs.time_sec, 3);

        abs += RelativeTime::new_time(0, 999_999_999);

        assert_eq!(abs.time_nsec, 0);
        assert_eq!(abs.time_sec, 4);

        abs -= RelativeTime::new_time(0, 999_999_999);

        assert_eq!(abs.time_nsec, 1);
        assert_eq!(abs.time_sec, 3);

        abs -= RelativeTime::new_time(0, 1);

        assert_eq!(abs.time_nsec, 0);
        assert_eq!(abs.time_sec, 3);

        abs -= RelativeTime::new_time(0, 500_000_000);

        assert_eq!(abs.time_nsec, 500_000_000);
        assert_eq!(abs.time_sec, 2);

        abs -= RelativeTime::new_time(0, 400_000_000);

        assert_eq!(abs.time_nsec, 100_000_000);
        assert_eq!(abs.time_sec, 2);

        abs -= RelativeTime::new_time(1, 200_000_000);

        assert_eq!(abs.time_nsec, 900_000_000);
        assert_eq!(abs.time_sec, 0);
    }
}

#[cfg(all(target_family = "unix", feature = "enable_mio_compat"))]
#[cfg(test)]
mod tests_mio_compat
{
    use std::time::Duration;

    use mio::{Events, Interest, Poll};

    use crate::{AbsoluteTime, FdTimerCom, RelativeTime, TimerReadRes, timer_portable::{TimerExpMode, TimerFd, TimerFdMioCompat, TimerFlags, TimerType, timer::{FdTimerRead, ModeTimeType}}};

    fn test1_handle(id: u64, time_dif: i64, timer_tm: AbsoluteTime, events: &Events, timer: &TimerFd)
    {
        let timer_tm_end = AbsoluteTime::now();
        let timer_tm_dif = timer_tm_end - timer_tm;

        println!("timer{}: armed: {} event: {} dif: {}", id, timer_tm, timer_tm_end, timer_tm_dif);

        assert_eq!(timer_tm_dif.get_sec(), time_dif);

        let mut ev_iter = events.iter();

        let event1 = ev_iter.next();
        assert_eq!(event1.is_some(), true);

        let event1 = event1.unwrap();

        assert_eq!(event1.token(), timer.get_token());

        let timer1_res = timer.read().unwrap();

        assert_eq!(timer1_res, TimerReadRes::Ok(1));

        // no events should left
        assert_eq!(ev_iter.next().is_none(), true);
    }

    #[test]
    fn mio_test1()
    {
        let mut poll = Poll::new().unwrap();
        let mut events = Events::with_capacity(2);

        let mut timer1 = 
            TimerFd::new("timer1".into(), TimerType::CLOCK_REALTIME, 
                TimerFlags::TFD_NONBLOCK)
                .unwrap();

        let mut timer2 = 
            TimerFd::new("timer2".into(), TimerType::CLOCK_REALTIME, 
                TimerFlags::TFD_NONBLOCK)
                .unwrap();

        let tok = timer1.get_token();

        poll
            .registry()
            .register(&mut timer1, tok, Interest::READABLE)
            .unwrap();

        let tok = timer2.get_token();

        poll
            .registry()
            .register(&mut timer2, tok, Interest::READABLE)
            .unwrap();

        let timer_tm = AbsoluteTime::now();

        // set to relative 2 sec
        timer1.set_time(TimerExpMode::<RelativeTime>::new_oneshot(2 as i64)).unwrap();

        // set to relative 3 sec
        timer2.set_time(TimerExpMode::<RelativeTime>::new_oneshot(3 as i64)).unwrap();

        // wait for timer 1
        poll.poll(&mut events, Some(Duration::from_millis(2500))).unwrap();
    
        test1_handle(1, 2, timer_tm, &events, &timer1);
        // --- timer 1 end

        // poll again
        // wait for timer 2
        poll.poll(&mut events, Some(Duration::from_millis(1300))).unwrap();

        test1_handle(2, 3, timer_tm, &events, &timer2);

    }
}

#[cfg(test)]
mod test_timer_fd
{
    use std::{time::{Duration, Instant, SystemTime}};

    use crate::timer_portable::timer::AbsoluteTime;

    use super::*;

    /// Simple test of [RelativeTime] once.
    #[test]
    fn test0()
    {
        let timer = 
            TimerFd::new(Cow::Borrowed("test"), TimerType::CLOCK_REALTIME, 
                TimerFlags::empty()).unwrap();

        let full_now = SystemTime::now();//chrono::offset::Utc::now();
        let s = Instant::now();

        let timer_mode1 = 
            TimerExpMode::<RelativeTime>::new_oneshot(
                Duration::from_secs(3)
            );

        let res = 
            timer
                .set_time(timer_mode1);
        println!("now: '{}', timer was set: '{}'", 
            full_now.duration_since(std::time::UNIX_EPOCH).unwrap().as_secs(), 
            full_now.duration_since(std::time::UNIX_EPOCH).unwrap().as_secs() + 3
        );

        assert_eq!(res.is_ok(), true, "{}", res.err().unwrap());

        let ovf = timer.read().unwrap().unwrap();

        let elapsed = full_now.elapsed().unwrap();


        assert_eq!(ovf, 1);

        println!("elapsed: {:?}, ts: {}", elapsed, full_now.duration_since(std::time::UNIX_EPOCH).unwrap().as_secs());

        assert_eq!((elapsed.as_millis() <= 3100), true);

        println!("Success");
        return;
    }


    /// Simple test of [AbsoluteTime] once.
    #[test]
    fn test1()
    {
        let timer = 
            TimerFd::new(Cow::Borrowed("test"), TimerType::CLOCK_REALTIME, 
                TimerFlags::empty()).unwrap();

        let abs_time_now = AbsoluteTime::now();
        let snow = abs_time_now + Duration::from_secs(3);

        let s = Instant::now();

        let timer_mode1 = 
            TimerExpMode::<AbsoluteTime>::new_oneshot(snow);

        let res = 
            timer
                .set_time(timer_mode1);
        println!("now: '{}', timer was set to: '{}'", abs_time_now, snow);

        assert_eq!(res.is_ok(), true, "{}", res.err().unwrap());

        let ovf = timer.read().unwrap().unwrap();

        let abs_time_now = AbsoluteTime::now();
        let e = s.elapsed();

        assert_eq!(ovf, 1);
        assert_eq!(abs_time_now.seconds_cmp(&snow), Ordering::Equal);

        println!("elapsed: {:?}, ts: {}", e, abs_time_now);

        assert_eq!((e.as_millis() <= 3100), true);

        println!("Success");
        return;
    }

    #[test]
    fn test1_1()
    {
        let timer = 
            TimerFdInternal::new(Cow::Borrowed("test"), TimerType::CLOCK_REALTIME, 
                TimerFlags::empty()).unwrap();

        let ts = common::get_current_timestamp();
        

        let set_ts = AbsoluteTime::from(ts) + RelativeTime::new_time(3, 0);
        let timer1_time = 
            TimerExpMode::<AbsoluteTime>::new_oneshot(set_ts);

        timer.set_time(timer1_time).unwrap();
        
        let res = timer.read().unwrap();

        let ts = common::get_current_timestamp();
        
        assert_eq!(AbsoluteTime::from(ts).seconds_cmp(&set_ts), Ordering::Equal);

        let set_ts = AbsoluteTime::from(ts) + RelativeTime::new_time(3, 0);
        let timer1_time = 
            TimerExpMode
                ::<AbsoluteTime>
                ::new_oneshot(set_ts);

        timer.set_time(timer1_time).unwrap(); 
        
        let res = timer.read().unwrap();

        let ts = common::get_current_timestamp();
        
        assert_eq!(AbsoluteTime::from(ts).seconds_cmp(&set_ts), Ordering::Equal);

        println!("Success");
        return;
    }

    #[tokio::test]
    async fn test2_fut()
    {
        let timer = 
            TimerFd::new(Cow::Borrowed("test"), TimerType::CLOCK_REALTIME, 
                TimerFlags::empty()).unwrap();

        let now = chrono::offset::Local::now().timestamp();
        let snow = now + 3;
        let s = Instant::now();

        let timer_mode1 = 
            TimerExpMode::<AbsoluteTime>::new_oneshot(
                AbsoluteTime::new_time(snow, 0).unwrap()
            );


        let res = 
            timer
                .set_time(timer_mode1);

        println!("timer was set: '{}' '{}'", now, snow);

        assert_eq!(res.is_ok(), true, "{}", res.err().unwrap());

        //let res = timer.await;

        //println!("{:?}", res);
        tokio::select! {
            ovf = timer => {
                let ts = chrono::offset::Local::now().timestamp();
                let e = s.elapsed();

                assert_eq!(ovf, Ok(TimerReadRes::Ok(1)));
                assert_eq!(ts, snow);

                println!("timeout e: {:?}, ts:{} snow:{}", e, ts, snow);
            }
        }
    }

    #[cfg(target_family = "unix")]
    #[tokio::test]
    async fn test3_tokio()
    {
        use tokio::io::{unix::AsyncFd, Interest};

        let mut timer: AsyncFd<TimerFd> = 
            AsyncFd::with_interest(
                TimerFd::new(Cow::Borrowed("test"), TimerType::CLOCK_REALTIME, 
                        TimerFlags::empty()).unwrap(), 
                Interest::READABLE
            ).unwrap();
            

        let now = chrono::offset::Local::now().timestamp();
        let snow = now + 3;
        let s = Instant::now();

        let timer_mode1 = 
            TimerExpMode::<AbsoluteTime>::new_oneshot(
                AbsoluteTime::new_time(snow, 0).unwrap()
            );

        let res = 
            timer
                .get_mut()
                .set_time(timer_mode1);

        println!("timer was set: '{}' '{}'", now, snow);

        assert_eq!(res.is_ok(), true, "{}", res.err().unwrap());

        tokio::select! {
            read_guard_res = timer.ready(Interest::READABLE) => 
            {
                let read_guard = read_guard_res.unwrap();

                let res = read_guard.get_inner().read();

                let ts = chrono::offset::Local::now().timestamp();
                let e = s.elapsed();

                assert_eq!(res, Ok(TimerReadRes::Ok(1)));
                assert_eq!(ts, snow);

                println!("timeout e: {:?}, ts:{} snow:{}", e, ts, snow);
            }
        }
    }

    #[test]
    fn test4_cancel()
    {
        let timer = 
            TimerFd::new(Cow::Borrowed("test"), TimerType::CLOCK_REALTIME,
                TimerFlags::TFD_NONBLOCK).unwrap();

        let now = chrono::offset::Local::now().timestamp();
        let snow = now + 3;
        let s = Instant::now();

        let timer_mode1 = 
            TimerExpMode::<AbsoluteTime>::new_oneshot(
                AbsoluteTime::new_time(snow, 0).unwrap()
            );

        let res = 
            timer
                .set_time(timer_mode1);
        println!("timer was set: '{}' '{}'", now, snow);

        assert_eq!(res.is_ok(), true, "{}", res.err().unwrap());

       

        let ovf = timer.read().unwrap();

        println!("{}", ovf);

        timer.unset_time().unwrap();

        let ovf = timer.read().unwrap();

         println!("{}", ovf);
        /*let ts = chrono::offset::Local::now().timestamp();
        let e = s.elapsed();

        assert_eq!(ovf, 1);
        assert_eq!(ts, snow);

        println!("elapsed: {:?}, ts: {}", e, ts);

        assert_eq!((e.as_millis() <= 3100), true);

        println!("Success");
        return;*/
    }
    
    #[test]
    fn test5_preiodic_with_delay()
    {
        let timer = 
            TimerFd::new(Cow::Borrowed("test"), TimerType::CLOCK_REALTIME, 
                TimerFlags::empty()).unwrap();

        let timer_mode1 = 
            TimerExpMode
                ::<RelativeTime>
                ::new_interval_with_init_delay(
                    RelativeTime::new_time(1, 0), 
                    RelativeTime::new_time(0, 500_000_000)
                );

       

        timer.set_time(timer_mode1).unwrap();


        let start = AbsoluteTime::now();

        let res = timer.read().unwrap();
        let end = AbsoluteTime::now();
        let diff = end - start;

        println!("timer was set s: '{}' e:'{}', diff = '{}' res: '{}'", start, end, diff, res);

        assert_eq!((diff.get_sec() == 0 && diff.get_nsec() <= 995_000_000) || (diff.get_sec() == 1), true);
        assert_eq!(res, TimerReadRes::Ok(1));
        
        let res = timer.read().unwrap();
        let end2 = AbsoluteTime::now();
        let diff = end2 - end;

        println!("timer was set s: '{}' e:'{}', diff = '{}' res: '{}'", end, end2, diff, res);
        assert_eq!(diff.get_sec(), 0);
        assert!(diff.get_nsec() >= 499_930_000 && diff.get_nsec() <= 500_900_000);
        assert_eq!(res, TimerReadRes::Ok(1));

        let res = timer.read().unwrap();
        let end3 = AbsoluteTime::now();
        let diff = end3 - end2;

        println!("timer was set s: '{}' e:'{}', diff = '{}' res: '{}'", end2, end3, diff, res);
        assert_eq!(diff.get_sec(), 0);
        assert!(diff.get_nsec() >= 499_430_000 && diff.get_nsec() <= 500_900_000);
        assert_eq!(res, TimerReadRes::Ok(1));

        timer.unset_time().unwrap();

        timer.set_nonblocking(true).unwrap();

        std::thread::sleep(Duration::from_millis(1000));
        let res = timer.read().unwrap();

        assert_eq!(res, TimerReadRes::WouldBlock);
    }
}