thetime 0.5.6

/// re-exported for easier access (no `use thetime::ntp::System;`, just `use thetime::System;`)
pub mod ntp;

/// re-exported for easier access (no `use thetime::system::System;`, just `use thetime::System;`)
pub mod system;

/// Timezones - a list of common timezones
/// Note: some names clash, examples Arabia Standard Time (AST) and Atlantic Standard Time (ATST), so we lengthen as shown above
/// 
/// # Examples
/// ```
/// use thetime::Tz;
/// println!("{}", Tz::UtcWet);
/// println!("{}", Tz::BstCet);
/// ```
pub mod timezones;

pub mod epoch {
    pub const UNIX: &str = "1970-01-01 00:00:00";
    pub const WINDOWS_NT: &str = "1601-01-01 00:00:00";
    pub const WEBKIT: &str = "1601-01-01 00:00:00";
    pub const MAC_OS: &str = "1904-01-01 00:00:00";
    pub const MAC_OS_CFA: &str = "2001-01-01 00:00:00";
    pub const SAS_4GL: &str = "1960-01-01 00:00:00";
}

use chrono::Local;
/// export the ntp file for easier access
pub use ntp::*;

/// export the system file for easier access
pub use system::*;

// export the timezones file for easier access
pub use timezones::*;

/// Reference time
pub const REF_TIME_1970: u64 = 2208988800;

/// Offset between 1601 and 1970
pub const OFFSET_1601: u64 = 11644473600;

/// Magic number for SAS 4GL (offset betwenn 1960 and 1970)
pub const MAGIC_SAS_4GL: i64 = 315619200;

/// Magic number for Macos epoch (offset between 1904 and 1970)
pub const MAGIC_MAC_OS: i64 = 2082844800;

/// Magic number for Macos Absolute epoch (offset between 2001 and 1970)
pub const MAGIC_MAC_OS_CFA: i64 = 978307200;
/// Returns the current time in seconds since Unix epoch
///
/// # Examples
/// ```rust
/// use thetime::now;
/// println!("{} seconds since Unix epoch", now());
/// ```
pub fn now() -> i64 {
    System::now().unix()
}

/// An enum to represent whether a time is in the past, present or future
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub enum RelativeTime {
    Past,
    Present,
    Future
}

impl core::fmt::Display for RelativeTime {
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        match self {
            RelativeTime::Past => write!(f, "past"),
            RelativeTime::Present => write!(f, "present"),
            RelativeTime::Future => write!(f, "future"),
        }
    }
}

/// Implements the core functionality of the library
/// 
/// The conversion methods from struct to various timestamps do support negatives where needed (everything but `windows_ns` as it uses the same epoch as we do)
/// 
/// Note that while all the examples use System time, as Ntp is not guaranteed to be included, Ntp can be used in exactly the same way in every one of these examples, as it too implements the Time trait.
pub trait Time {
    /// Get current time, returning the relevant struct
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{} says the system, but {} says the server", System::now(), System::now());
    /// ```
    fn now() -> Self;

    /// Parse a string into a time struct
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("The time was {}", System::strptime("2015-01-18 23:16:09", "%Y-%m-%d %H:%M:%S"));
    /// ```
    fn strptime<T: ToString, G: ToString>(s: T, format: G) -> Self;
    /// Get the time in seconds since Unix epoch
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{} seconds since Unix epoch", System::now().unix());
    /// println!("{} seconds since Unix epoch from pool.ntp.org", System::now().unix());
    /// ```
    fn unix(&self) -> i64;

    /// Get the time in milliseconds since Unix epoch
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{} milliseconds since Unix epoch", System::now().unix_ms());
    /// println!("{} milliseconds since Unix epoch from pool.ntp.org", System::now().unix_ms());
    /// ```
    fn unix_ms(&self) -> i64;

    /// Gets the time in nanoseconds (approximate) since Windows epoch (`1601-01-01 00:00:00`)
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{} nanoseconds since Windows epoch", System::now().windows_ns());
    /// println!("{} nanoseconds since Windows epoch from pool.ntp.org", System::now().windows_ns());
    /// ```
    fn windows_ns(&self) -> i64 {
        ((self.epoch() as f64) * 1e4) as i64
    }

    /// Gets the time in microseconds (approximate) since Webkit epoch (`1601-01-01 00:00:00`)
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{} microseconds since Webkit epoch", System::now().webkit());
    /// println!("{} microseconds since Webkit epoch from pool.ntp.org", System::now().webkit());
    /// ```
    fn webkit(&self) -> i64 {
        ((self.epoch() as f64) * 1e3) as i64
    }

    /// Get the time in seconds since the Mac OS epoch (1904-01-01 00:00:00)
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{} seconds since Mac OS epoch", System::now().mac_os());
    /// println!("{} seconds since Mac OS epoch from pool.ntp.org", System::now().mac_os());
    /// ```
    fn mac_os(&self) -> i64 {
        self.unix() + MAGIC_MAC_OS
    }

    /// Get the time in seconds since the Mac OS Absolute epoch (2001-01-01 00:00:00)
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{} seconds since Mac OS Absolute epoch", System::now().mac_os_cfa());
    /// println!("{} seconds since Mac OS Absolute epoch from pool.ntp.org", System::now().mac_os_cfa());
    /// ```
    fn mac_os_cfa(&self) -> i64 {
        self.unix() - MAGIC_MAC_OS_CFA
    }

    /// Get the time in seconds since the SAS 4GL epoch (1960-01-01 00:00:00)
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{} seconds since SAS 4GL epoch", System::now().sas_4gl());
    /// println!("{} seconds since SAS 4GL epoch from pool.ntp.org", System::now().sas_4gl());
    /// ```
    fn sas_4gl(&self) -> i64 {
        self.unix() + MAGIC_SAS_4GL
    }
    /// Format the time according to the given format string
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().strftime("%Y-%m-%d %H:%M:%S"));
    /// println!("{}", System::now().strftime("%Y-%B-%d %H:%M:%S"));
    /// ```
    fn strftime(&self, format: &str) -> String;

    /// Get the time since the epoch we use (`1601-01-01 00:00:00`). we use this for full compataibility with Windows
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{} milliseconds since the epoch we use", System::now().epoch());
    /// println!("{} milliseconds since the epoch we use from pool.ntp.org", System::now().epoch());
    /// ```
    fn epoch(&self) -> i64 {
        self.unix_ms() + (OFFSET_1601 as i64 * 1000i64)
    }

    /// pretty print the time object
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, StrTime};
    /// let date2017 = "2017-01-01 00:00:00".parse_time::<System>("%Y-%m-%d %H:%M:%S");
    /// println!("2017 - {}", date2017.pretty());
    /// assert_eq!(date2017.pretty(), "2017-01-01 00:00:00");
    /// ```
    fn pretty(&self) -> String {
        self.strftime("%Y-%m-%d %H:%M:%S")
    }

    /// Don't use this method, it's for internal use only (for instantiating structs from timestamps using the `1601-01-01 00:00:00` epoch)
    #[doc(hidden)]
    fn from_epoch(timestamp: u64) -> Self;

    /// Don't use this method, it's for internal use only (returns raw struct ms)
    #[doc(hidden)]
    fn raw(&self) -> u64;

    /// Returns the date formatted in ISO8601 format
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().iso8601());
    /// println!("{}", System::now().iso8601());
    /// ```
    fn iso8601(&self) -> String {
        self.strftime("%Y-%m-%d %H:%M:%S.") + &(self.raw() % 1000).to_string()
    }

    /// Returns the date formatted in RFC3339 format
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().rfc3339());
    /// println!("{}", System::now().rfc3339());
    /// ```
    fn rfc3339(&self) -> String {
        self.strftime("%Y-%m-%dT%H:%M:%S.") + &(self.raw() % 1000).to_string() + "Z"
    }

    /// internal only
    #[doc(hidden)]
    fn utc_offset(&self) -> i32;

    /// Gets the timezone offset in the format HH:MM
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().tz_offset());
    /// println!("{}", System::now().tz_offset());
    /// ```
    fn tz_offset(&self) -> String {
        let offset = self.utc_offset();
        let sign = if offset < 0 { "-" } else { "+" };
        let offset = offset.abs();
        let hours = offset / 3600;
        let minutes = (offset % 3600) / 60;
        format!("{}{:02}:{:02}", sign, hours, minutes)
    }

    /// Represents the timezone as an enum
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{:?}", System::now().tz_enum());
    /// println!("{:?}", System::now().tz_enum());
    /// ```
    fn tz_enum(&self) -> Option<Tz> {
        Tz::from_offset(-self.utc_offset())
    }

    /// Changes the timezone offset of the time object, where `offset` is in the form "+|-[0-5][0-9]:[0-5][0-9]"
    /// Note that this change is relative to UTC, not the current timezone
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().change_tz("+01:00"));
    /// println!("{}", System::now().change_tz("-01:00"));
    /// ```
    fn change_tz<T: ToString>(&self, offset: T) -> Self 
    where Self: Sized {
        let offset = offset.to_string();
        let offset_seconds = offset[1..3].parse::<i32>().unwrap() * 3600
            + offset[4..6].parse::<i32>().unwrap() * 60;

        let offset_seconds = if offset.starts_with('+') {
            offset_seconds
        } else {
            -offset_seconds
        };

        let duped_secs = offset_seconds;


        let utc_self = Self::from_epoch_offset((self.raw() as i64 + (self.utc_offset() as i64 * 1000i64)) as u64, 0);


        Self::from_epoch_offset((utc_self.raw() as i64 + (offset_seconds as i64 * 1000i64)) as u64, -duped_secs)
    }

    /// Changes the timezone offset of the time object to the local timezone
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().local());
    /// println!("{}", System::now().local());
    /// ```
    fn local(&self) -> Self
    where Self: Sized {
        self.change_tz(Local::now().format("%:z").to_string())
    }

    /// add an amount in seconds to a time object
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().add_seconds(3600));
    /// println!("{}", System::now().add_seconds(3600));
    /// ```
    fn add_seconds(&self, duration: i64) -> Self
    where Self: Sized {
        Self::from_epoch((self.raw() as i64 + (duration * 1000)) as u64)
    }

    /// add an amount in minutes to a time object
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().add_minutes(60));
    /// println!("{}", System::now().add_minutes(-60));
    /// ```
    fn add_minutes(&self, minutes: i64) -> Self
    where Self: Sized {
        self.add_seconds(minutes * 60)
    }

    /// add an amount in hours to a time object
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().add_minutes(60));
    /// println!("{}", System::now().add_minutes(24));
    /// ```
    fn add_hours(&self, hours: i64) -> Self
    where Self: Sized {
        self.add_seconds(hours * 3600)
    }

    /// add an amount in days to a time object
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().add_days(7));
    /// println!("{}", System::now().add_days(24));
    /// ```
    fn add_days(&self, days: i64) -> Self
    where Self: Sized {
        self.add_seconds(days * 86400)
    }

    /// add an amount in weeks to a time object
    /// we stop at weeks to avoid potential leap year confusion
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// println!("{}", System::now().add_weeks(7));
    /// println!("{}", System::now().add_weeks(52));
    /// ```
    fn add_weeks(&self, weeks: i64) -> Self
    where Self: Sized {
        self.add_seconds(weeks * 604800)
    }


    /// determine whether a time object is in the past, present or future
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time};
    /// let x = System::now();
    /// let y = System::now();
    /// println!("{} is in the {}", x, x.past_future(&y));
    /// println!("{} is in the {}", y, y.past_future(&x));
    /// ```
    fn past_future<T: Time>(&self, other: &T) -> RelativeTime {
        #[allow(clippy::comparison_chain)] // this is a false positive: we don't want to use a match statement here
        if self.raw() < other.raw() {
            RelativeTime::Past
        } else if self.raw() > other.raw() {
            RelativeTime::Future
        } else {
            RelativeTime::Present
        }
    }

    /// add a duration to a time object
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, ImplsDuration};
    /// let x = System::now();
    /// println!("{}", x.add_duration(chrono::Duration::seconds(3600)));
    /// ```
    fn add_duration<T: ImplsDuration>(&self, duration: T) -> Self
        where Self: Sized {
        self.add_seconds(duration.num_seconds())
    }

    /// cast a time object to another time object
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Ntp, Time};
    /// let x = System::now();
    /// println!("{}", x.cast::<Ntp>());
    /// ```
    fn cast<T: Time>(&self) -> T
    where Self: Sized {
        T::from_epoch(self.raw())
    }

    /// internal only
    #[doc(hidden)]
    fn from_epoch_offset(timestamp: u64, offset: i32) -> Self;
}

/// A trait so that we can use chrono::Duration and core::time::Duration interchangeably in the `Time::add_duration` function
pub trait ImplsDuration {
    fn num_seconds(&self) -> i64;
}
impl ImplsDuration for chrono::Duration {
    fn num_seconds(&self) -> i64 {
        self.num_seconds()
    }
}

impl ImplsDuration for core::time::Duration {
    fn num_seconds(&self) -> i64 {
        self.as_secs() as i64
    }
}

/// Implements the diff functions (optional)
pub trait TimeDiff {
    /// Get the difference between two times in seconds
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, TimeDiff, StrTime, IntTime};
    /// let x = "2018-01-01 00:00:00".parse_time::<System>("%Y-%m-%d %H:%M:%S");
    /// let y = "2017-01-01 00:00:00".parse_time::<System>("%Y-%m-%d %H:%M:%S");
    /// println!("{} seconds difference", x.diff(&y));
    /// assert_eq!(x.diff(&y), 31536000u64);
    /// ```
    fn diff<T: Time>(&self, other: &T) -> u64
    where
        Self: Time,
    {
        self.raw().abs_diff(other.raw()) / 1000
    }

    /// Get the difference between two times in milliseconds
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, TimeDiff};
    /// let x = System::now();
    /// let y = System::now();
    /// println!("{} milliseconds difference", x.diff_ms(&y));
    /// ```
    fn diff_ms<T: Time>(&self, other: &T) -> u64
    where
        Self: Time,
    {
        self.raw().abs_diff(other.raw())
    }
}

/// Provides wrappers on string std types to parse into time structs
pub trait StrTime {
    /// Parse a string into a time struct of choice
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, StrTime};
    /// println!("2017 - {}", "2017-01-01 00:00:00".parse_time::<System>("%Y-%m-%d %H:%M:%S"));
    /// println!("{}", "2017-01-01 00:00:00".parse_time::<System>("%Y-%m-%d %H:%M:%S").unix());
    /// assert_eq!("2017-01-01 00:00:00".parse_time::<System>("%Y-%m-%d %H:%M:%S").unix(), 1483228800);
    /// ```
    fn parse_time<T: Time>(&self, format: &str) -> T
    where
        Self: core::fmt::Display,
    {
        T::strptime(self, format)
    }

    /// Parse a string into a time struct of choice, using the ISO8601 format
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, StrTime};
    /// println!("2017 - {}", "2017-01-01T00:00:00.000".strp_iso8601::<System>());
    /// println!("{}", "2017-01-01T00:00:00.000".strp_iso8601::<System>().unix());
    /// assert_eq!("2017-01-01T00:00:00.000".strp_iso8601::<System>().unix(), 1483228800);
    /// ```
    fn strp_iso8601<T: Time>(&self) -> T
    where
        Self: core::fmt::Display,
    {
        T::strptime(self, "%Y-%m-%dT%H:%M:%S.%f")
    }

    /// Parse a string into a time struct of choice, using the RFC3339 format
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, StrTime};
    /// println!("2017 - {}", "2017-01-01T00:00:00.000Z".strp_rf3339::<System>());
    /// println!("{}", "2017-01-01T00:00:00.000Z".strp_rf3339::<System>().unix());
    /// assert_eq!("2017-01-01T00:00:00.000Z".strp_rf3339::<System>().unix(), 1483228800);
    /// ```
    fn strp_rf3339<T: Time>(&self) -> T
    where
        Self: core::fmt::Display,
    {
        T::strptime(self, "%Y-%m-%dT%H:%M:%S.%fZ")
    }
}

/// Provides wrappers on integer std types to parse into time structs, and also to pretty print timestamp integers
///
/// Note: If there is an error, the function will return the Unix epoch time for the struct of choice
/// 
/// You can only convert from positive integers, as negative integers are not supported, as they cannot be represented in the time structs. While it would be possible to fix this, I don't think it is a needed feature at the moment.
pub trait IntTime: core::fmt::Display + Into<u64> {
    /// Convert an integer into a time struct of choice
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, IntTime};
    /// assert_eq!(1483228800u32.unix::<System>().pretty(), "2017-01-01 00:00:00");
    /// ```
    fn unix<T: Time>(self) -> T {
        let unix: u64 = self.into();
        T::from_epoch((unix + OFFSET_1601) * 1000)
    }

    /// Convert an integer into a time struct of choice, from a Windows timestamp (100ns since `1601-01-01 00:00:00`)
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, IntTime};
    /// assert_eq!(131277024000000000u64.windows_ns::<System>().pretty(),"2017-01-01 00:00:00");
    /// ```
    fn windows_ns<T: Time>(self) -> T {
        T::from_epoch(self.into() / (1e4 as u64))
    }

    /// Convert an integer into a time struct of choice, from a Webkit timestamp (microseconds since `1601-01-01 00:00:00`)
    /// 
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, IntTime};
    /// println!("2017 - {:#?}", 13127702400000000u64.webkit::<System>());
    /// assert_eq!(13127702400000000u64.webkit::<System>().strftime("%Y-%m-%d %H:%M:%S"), "2017-01-01 00:00:00");
    /// ```
    fn webkit<T: Time>(self) -> T {
        T::from_epoch(self.into() / (1e3 as u64))
    }

    /// Convert an integer into a time struct of choice, from a Mac OS timestamp (seconds since 1904-01-01 00:00:00)
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, IntTime};
    /// println!("2024 - {:#?}", 3787310789u64.mac_os::<System>());
    /// assert_eq!(3787310789u64.mac_os::<System>().strftime("%Y-%m-%d %H:%M:%S"), "2024-01-05 14:46:29");
    /// ```
    fn mac_os<T: Time>(self) -> T {
        let selfu64: u64 = self.into();
        let selfi64: i64 = selfu64 as i64;
        let unix: i64 = selfi64 - MAGIC_MAC_OS;
        T::from_epoch((unix + (OFFSET_1601 as i64)) as u64 * 1000)
    }

    /// Convert an integer into a time struct of choice, from a Mac OS Absolute timestamp (seconds since 2001-01-01 00:00:00)
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, IntTime};
    /// println!("2024 - {:#?}", 726158877u64.mac_os_cfa::<System>());
    /// assert_eq!(726158877u64.mac_os_cfa::<System>().strftime("%Y-%m-%d %H:%M:%S"), "2024-01-05 14:47:57");
    /// ```
    fn mac_os_cfa<T: Time>(self) -> T {
        let selfu64: u64 = self.into();
        let unix: u64 = selfu64 + MAGIC_MAC_OS_CFA as u64;
        T::from_epoch((unix + OFFSET_1601) * 1000)
    }

    /// Convert an integer into a time struct of choice, from a SAS 4GL timestamp (seconds since 1960-01-01 00:00:00)
    ///
    /// # Examples
    /// ```rust
    /// use thetime::{System, Time, IntTime};
    /// println!("2024 - {:#?}", 2020003754u64.sas_4gl::<System>());
    /// assert_eq!(2020003754u64.sas_4gl::<System>().strftime("%Y-%m-%d %H:%M:%S"), "2024-01-04 16:09:14");
    /// ```
    fn sas_4gl<T: Time>(self) -> T {
        let selfu64: u64 = self.into();
        let selfi64: i64 = selfu64 as i64;
        let unix: i64 = selfi64 - MAGIC_SAS_4GL;
        T::from_epoch((unix + (OFFSET_1601 as i64)) as u64 * 1000)
    }

    /// Prints the time duration in a formatted string. Note that this only goes up to weeks, as years are rather subjective
    ///
    /// # Examples
    /// ```rust
    /// use thetime::IntTime;
    /// let duration = 3600u64;
    /// let formatted = duration.ts_print();
    /// assert_eq!(formatted, "0w 0d 1h 0m 0s");
    /// ```
    fn ts_print(self) -> String {
        let duration = chrono::Duration::seconds(self.into() as i64);
        format!(
            "{}w {}d {}h {}m {}s",
            duration.num_weeks(),
            duration.num_days() % 7,
            duration.num_hours() % 24,
            duration.num_minutes() % 60,
            duration.num_seconds() % 60
        )
    }
}

/// implement the StrTime trait for `String` types
impl StrTime for str {}

/// implement the StrTime trait for `&str` types
impl StrTime for String {}

/// implement the IntTime trait for all integer types that implement conversion to u64
impl<T: core::fmt::Display + Into<u64>> IntTime for T {}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_system() {
        let x = System::now();
        println!("{}", x);
        println!("{}", x.unix_ms());
        println!("{}", x.strftime("%Y-%m-%d %H:%M:%S"));
    }

    #[test]
    fn test_ntp() {
        let x = Ntp::now();
        println!("{:#?}", x);
        println!("{}", x.unix_ms());
        println!("{}", x);
    }

    #[test]
    fn strptime() {
        let x = System::strptime("2015-02-18 23:16:09.234", "%Y-%m-%d %H:%M:%S%.3f");
        println!("2015 - {}", x);
        let x = Ntp::strptime("2021-01-01 00:00:00 +0000", "%Y-%m-%d %H:%M:%S %z");
        println!("2021 - {}", x);
        assert_eq!(x.unix(), 1609459200);
        println!("1950 - {}", Ntp::strptime("1950-01-01 00:00:00", "%Y-%m-%d %H:%M:%S"))
    }

    #[test]
    fn str_time() {
        let date2017 = "2017-01-01 00:00:00".parse_time::<System>("%Y-%m-%d %H:%M:%S");
        println!("2017 - {}", date2017);
        assert_eq!(date2017.unix(), 1483228800);
    }

    #[test]
    fn time_diff() {
        let x = "2015-01-01 00:00:00".parse_time::<System>("%Y-%m-%d %H:%M:%S");
        let y = "2017-01-01 00:00:00".parse_time::<System>("%Y-%m-%d %H:%M:%S");
        println!("{} difference", y.diff(&x).ts_print());
        println!("{} milliseconds difference", x.diff_ms(&y));
        assert_eq!(x.diff(&y), 63158400u64);
    }

    #[test]
    fn int_ntp_time() {
        assert_eq!(1483228800u32.unix::<Ntp>().pretty(), "2017-01-01 00:00:00");
        assert_eq!(
            131277024000000000u64.windows_ns::<Ntp>().pretty(),
            "2017-01-01 00:00:00"
        );
        assert_eq!(
            3787310789u64.mac_os::<Ntp>().pretty(),
            "2024-01-05 14:46:29"
        );
        assert_eq!(
            726158877u32.mac_os_cfa::<Ntp>().pretty(),
            "2024-01-05 14:47:57"
        );
        assert_eq!(0u32.sas_4gl::<Ntp>().pretty(), "1960-01-01 00:00:00");
    }

    #[test]
    fn int_system_time() {
        assert_eq!(1483228800u32.unix::<System>().pretty(), "2017-01-01 00:00:00");
        assert_eq!(
            131277024000000000u64.windows_ns::<System>().pretty(),
            "2017-01-01 00:00:00"
        );
        assert_eq!(
            3787310789u64.mac_os::<System>().pretty(),
            "2024-01-05 14:46:29"
        );
        assert_eq!(
            726158877u32.mac_os_cfa::<System>().pretty(),
            "2024-01-05 14:47:57"
        );
        assert_eq!(0u32.sas_4gl::<System>().pretty(), "1960-01-01 00:00:00");
    }

    #[test]
    fn windows_tests() {
        let x = System::now();
        println!("{} lots of 100ns since Windows epoch", x.windows_ns());
    }

    #[test]
    fn mac_os() {
        let x = System::now();
        println!("{} seconds since Mac OS epoch", x.mac_os());
        println!("{} seconds since Mac OS Absolute epoch", x.mac_os_cfa());
    }

    #[test]
    fn sas_4gl() {
        let x = System::now();
        println!("{} seconds since SAS 4GL epoch", x.sas_4gl());
    }

    #[test]
    fn rfc3339_iso8601() {
        let x = System::now();
        println!("{}", x.iso8601());
        println!("{}", x.rfc3339());
    }

    #[test]
    fn strptime_rfc_and_iso() {
        let x = "2017-01-01T00:00:00.000".strp_iso8601::<System>();
        let y = "2017-01-01T00:00:00.000Z".strp_rf3339::<System>();
        assert_eq!(x.unix(), 1483228800);
        assert_eq!(y.unix(), 1483228800);
    }

    #[test]
    fn tz_tests() {
        let x = Ntp::now();
        // println!("{}", x.tz_offset());
        // println!("{}", x);
        println!("{:#?}", x);
        println!("{}", x.change_tz("+01:00"));
        println!("{}", x.change_tz("-01:00"));
    }

    #[test]
    fn test_add_seconds() {
        let x = System::now();
        println!("{}", x.add_seconds(3600));
    } 

    #[test]
    fn test_add_minshoursdaysweeks() {
        let x = System::now();
        println!("{}", x.add_minutes(60));
        println!("{}", x.add_hours(24));
        println!("{}", x.add_days(7));
        println!("{}", x.add_weeks(52));
    }

    #[test]
    fn long_ago_dates() {
        let x = System::from_epoch(0);
        println!("{}", x);
        println!("{}", x.unix());
        println!("{}", x.strftime("%Y-%m-%d %H:%M:%S"));
    }

    #[test]
    fn test_past_future() {
        let x = "2029-01-01T00:00:00.000".strp_iso8601::<System>();
        let y = "2017-01-01T00:00:00.000Z".strp_rf3339::<System>();
        println!("{} is in the {}", x, x.past_future(&y));
        println!("{} is in the {}", y, y.past_future(&x));
    }

    #[test]
    fn test_add_duration() {
        let x = System::now();
        
        println!("{}", x.add_duration(std::time::Duration::from_secs(3600)));

        println!("{}", x.add_duration(chrono::Duration::seconds(3600)));
    }
    #[test]
    fn test_local() {
        let x = System::now();
        println!("{}", x.local());
    }

    #[test]
    fn test_tz_enum() {
        let x = System::now().change_tz("+08:00");
        println!("{}", x.tz_enum().unwrap_or_default());
        println!("{}", Tz::from_offset(3600).unwrap_or_default());
        println!("{}", Tz::from_offset(0).unwrap_or_default()); // Some(UtcWet)
        println!("{}", Tz::from_offset(3600).unwrap_or_default()); // Some(BstCet)
        println!("{}", Tz::from_offset(7200).unwrap_or_default()); // Some(CestEet)
        println!("{}", Tz::from_offset(123456).unwrap_or_default()); // None
        println!("{}", Tz::Acst.offset_struct(System::now()));
    }

    #[test]
    fn huge_number() {
        let x = System::strptime("+262143-01-01 00:00:00", "%Y-%m-%d %H:%M:%S");
        println!("{}", x);
    }

    #[test]
    fn test_cast() {
        let x = System::now();
        println!("{:#?}", x.cast::<Ntp>());
    }
}