// Copyright 2015-2016 Brian Smith.

//

// Permission to use, copy, modify, and/or distribute this software for any

// purpose with or without fee is hereby granted, provided that the above

// copyright notice and this permission notice appear in all copies.

//

// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES

// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR

// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

//! Conversions into the library's time type.

/// The time type.

///

/// Internally this is merely a UNIX timestamp: a count of non-leap

/// seconds since the start of 1970.  This type exists to assist

/// unit-of-measure correctness.

#[derive(Debug, Clone, Copy, PartialEq, PartialOrd)]

pub struct Time(u64);

impl Time {

    /// Create a `webpki::Time` from a unix timestamp.

    ///

    /// It is usually better to use the less error-prone

    /// `webpki::Time::try_from(time: std::time::SystemTime)` instead when

    /// `std::time::SystemTime` is available (when `#![no_std]` isn't being

    /// used).

    #[allow(clippy::must_use_candidate)]

    pub fn from_seconds_since_unix_epoch(secs: u64) -> Self {

        Self(secs)

    }

}

#[cfg(feature = "std")]

impl core::convert::TryFrom<std::time::SystemTime> for Time {

    type Error = std::time::SystemTimeError;

    /// Create a `webpki::Time` from a `std::time::SystemTime`.

    ///

    /// # Example:

    ///

    /// Construct a `webpki::Time` from the current system time:

    ///

    /// ```

    /// # extern crate ring;

    /// # extern crate webpki;

    /// #

    /// #![cfg(feature = "std")]

    /// use std::{convert::TryFrom, time::{SystemTime, SystemTimeError}};

    ///

    /// # fn foo() -> Result<(), SystemTimeError> {

    /// let time = webpki::Time::try_from(SystemTime::now())?;

    /// # Ok(())

    /// # }

    /// ```

    fn try_from(value: std::time::SystemTime) -> Result<Self, Self::Error> {

        value

            .duration_since(std::time::UNIX_EPOCH)

            .map(|d| Self::from_seconds_since_unix_epoch(d.as_secs()))

    }

}