#![doc(html_root_url = "https://docs.rs/prost-types/0.9.0")]

//! Protocol Buffers well-known types.
//!
//! Note that the documentation for the types defined in this crate are generated from the Protobuf
//! definitions, so code examples are not in Rust.
//!
//! See the [Protobuf reference][1] for more information about well-known types.
//!
//! [1]: https://developers.google.com/protocol-buffers/docs/reference/google.protobuf

#![cfg_attr(not(feature = "std"), no_std)]

use core::convert::TryFrom;
use core::i32;
use core::i64;
use core::time;

include!("protobuf.rs");
pub mod compiler {
    include!("compiler.rs");
}

// The Protobuf `Duration` and `Timestamp` types can't delegate to the standard library equivalents
// because the Protobuf versions are signed. To make them easier to work with, `From` conversions
// are defined in both directions.

const NANOS_PER_SECOND: i32 = 1_000_000_000;
const NANOS_MAX: i32 = NANOS_PER_SECOND - 1;

impl Duration {
    /// Normalizes the duration to a canonical format.
    ///
    /// Based on [`google::protobuf::util::CreateNormalized`][1].
    /// [1]: https://github.com/google/protobuf/blob/v3.3.2/src/google/protobuf/util/time_util.cc#L79-L100
    pub fn normalize(&mut self) {
        // Make sure nanos is in the range.
        if self.nanos <= -NANOS_PER_SECOND || self.nanos >= NANOS_PER_SECOND {
            if let Some(seconds) = self
                .seconds
                .checked_add((self.nanos / NANOS_PER_SECOND) as i64)
            {
                self.seconds = seconds;
                self.nanos %= NANOS_PER_SECOND;
            } else if self.nanos < 0 {
                // Negative overflow! Set to the least normal value.
                self.seconds = i64::MIN;
                self.nanos = -NANOS_MAX;
            } else {
                // Positive overflow! Set to the greatest normal value.
                self.seconds = i64::MAX;
                self.nanos = NANOS_MAX;
            }
        }

        // nanos should have the same sign as seconds.
        if self.seconds < 0 && self.nanos > 0 {
            if let Some(seconds) = self.seconds.checked_add(1) {
                self.seconds = seconds;
                self.nanos -= NANOS_PER_SECOND;
            } else {
                // Positive overflow! Set to the greatest normal value.
                debug_assert_eq!(self.seconds, i64::MAX);
                self.nanos = NANOS_MAX;
            }
        } else if self.seconds > 0 && self.nanos < 0 {
            if let Some(seconds) = self.seconds.checked_sub(1) {
                self.seconds = seconds;
                self.nanos += NANOS_PER_SECOND;
            } else {
                // Negative overflow! Set to the least normal value.
                debug_assert_eq!(self.seconds, i64::MIN);
                self.nanos = -NANOS_MAX;
            }
        }
        // TODO: should this be checked?
        // debug_assert!(self.seconds >= -315_576_000_000 && self.seconds <= 315_576_000_000,
        //               "invalid duration: {:?}", self);
    }
}

/// Converts a `std::time::Duration` to a `Duration`.
impl From<time::Duration> for Duration {
    fn from(duration: time::Duration) -> Duration {
        let seconds = duration.as_secs();
        let seconds = if seconds > i64::MAX as u64 {
            i64::MAX
        } else {
            seconds as i64
        };
        let nanos = duration.subsec_nanos();
        let nanos = if nanos > i32::MAX as u32 {
            i32::MAX
        } else {
            nanos as i32
        };
        let mut duration = Duration { seconds, nanos };
        duration.normalize();
        duration
    }
}

impl TryFrom<Duration> for time::Duration {
    type Error = time::Duration;

    /// Converts a `Duration` to a result containing a positive (`Ok`) or negative (`Err`)
    /// `std::time::Duration`.
    fn try_from(mut duration: Duration) -> Result<time::Duration, time::Duration> {
        duration.normalize();
        if duration.seconds >= 0 {
            Ok(time::Duration::new(
                duration.seconds as u64,
                duration.nanos as u32,
            ))
        } else {
            Err(time::Duration::new(
                (-duration.seconds) as u64,
                (-duration.nanos) as u32,
            ))
        }
    }
}

impl Timestamp {
    /// Normalizes the timestamp to a canonical format.
    ///
    /// Based on [`google::protobuf::util::CreateNormalized`][1].
    /// [1]: https://github.com/google/protobuf/blob/v3.3.2/src/google/protobuf/util/time_util.cc#L59-L77
    #[cfg(feature = "std")]
    pub fn normalize(&mut self) {
        // Make sure nanos is in the range.
        if self.nanos <= -NANOS_PER_SECOND || self.nanos >= NANOS_PER_SECOND {
            if let Some(seconds) = self
                .seconds
                .checked_add((self.nanos / NANOS_PER_SECOND) as i64)
            {
                self.seconds = seconds;
                self.nanos %= NANOS_PER_SECOND;
            } else if self.nanos < 0 {
                // Negative overflow! Set to the earliest normal value.
                self.seconds = i64::MIN;
                self.nanos = 0;
            } else {
                // Positive overflow! Set to the latest normal value.
                self.seconds = i64::MAX;
                self.nanos = 999_999_999;
            }
        }

        // For Timestamp nanos should be in the range [0, 999999999].
        if self.nanos < 0 {
            if let Some(seconds) = self.seconds.checked_sub(1) {
                self.seconds = seconds;
                self.nanos += NANOS_PER_SECOND;
            } else {
                // Negative overflow! Set to the earliest normal value.
                debug_assert_eq!(self.seconds, i64::MIN);
                self.nanos = 0;
            }
        }

        // TODO: should this be checked?
        // debug_assert!(self.seconds >= -62_135_596_800 && self.seconds <= 253_402_300_799,
        //               "invalid timestamp: {:?}", self);
    }
}

/// Implements the unstable/naive version of `Eq`: a basic equality check on the internal fields of the `Timestamp`.
/// This implies that `normalized_ts != non_normalized_ts` even if `normalized_ts == non_normalized_ts.normalized()`.
#[cfg(feature = "std")]
impl Eq for Timestamp {}

#[cfg(feature = "std")]
#[allow(clippy::derive_hash_xor_eq)] // Derived logic is correct: comparing the 2 feilds for equality
impl std::hash::Hash for Timestamp {
    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
        self.seconds.hash(state);
        self.nanos.hash(state);
    }
}

#[cfg(feature = "std")]
impl From<std::time::SystemTime> for Timestamp {
    fn from(system_time: std::time::SystemTime) -> Timestamp {
        let (seconds, nanos) = match system_time.duration_since(std::time::UNIX_EPOCH) {
            Ok(duration) => {
                let seconds = i64::try_from(duration.as_secs()).unwrap();
                (seconds, duration.subsec_nanos() as i32)
            }
            Err(error) => {
                let duration = error.duration();
                let seconds = i64::try_from(duration.as_secs()).unwrap();
                let nanos = duration.subsec_nanos() as i32;
                if nanos == 0 {
                    (-seconds, 0)
                } else {
                    (-seconds - 1, 1_000_000_000 - nanos)
                }
            }
        };
        Timestamp { seconds, nanos }
    }
}

/// Indicates that a [`Timestamp`] could not be converted to
/// [`SystemTime`][std::time::SystemTime] because it is out of range.
///
/// The range of times that can be represented by `SystemTime` depends on the platform.
/// All `Timestamp`s are likely representable on 64-bit Unix-like platforms, but
/// other platforms, such as Windows and 32-bit Linux, may not be able to represent
/// the full range of `Timestamp`s.
#[cfg(feature = "std")]
#[derive(Debug)]
#[non_exhaustive]
pub struct TimestampOutOfSystemRangeError {
    pub timestamp: Timestamp,
}

#[cfg(feature = "std")]
impl core::fmt::Display for TimestampOutOfSystemRangeError {
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        write!(
            f,
            "{:?} is not representable as a `SystemTime` because it is out of range",
            self
        )
    }
}

#[cfg(feature = "std")]
impl std::error::Error for TimestampOutOfSystemRangeError {}

#[cfg(feature = "std")]
impl TryFrom<Timestamp> for std::time::SystemTime {
    type Error = TimestampOutOfSystemRangeError;

    fn try_from(mut timestamp: Timestamp) -> Result<std::time::SystemTime, Self::Error> {
        let orig_timestamp = timestamp.clone();
        timestamp.normalize();

        let system_time = if timestamp.seconds >= 0 {
            std::time::UNIX_EPOCH.checked_add(time::Duration::from_secs(timestamp.seconds as u64))
        } else {
            std::time::UNIX_EPOCH
                .checked_sub(time::Duration::from_secs((-timestamp.seconds) as u64))
        };

        let system_time = system_time.and_then(|system_time| {
            system_time.checked_add(time::Duration::from_nanos(timestamp.nanos as u64))
        });

        system_time.ok_or(TimestampOutOfSystemRangeError {
            timestamp: orig_timestamp,
        })
    }
}

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

    use proptest::prelude::*;

    use super::*;

    #[cfg(feature = "std")]
    proptest! {
        #[test]
        fn check_system_time_roundtrip(
            system_time in SystemTime::arbitrary(),
        ) {
            prop_assert_eq!(SystemTime::try_from(Timestamp::from(system_time)).unwrap(), system_time);
        }

        #[test]
        fn check_timestamp_roundtrip_via_system_time(
            seconds in i64::arbitrary(),
            nanos in i32::arbitrary(),
        ) {
            let mut timestamp = Timestamp { seconds, nanos };
            timestamp.normalize();
            if let Ok(system_time) = SystemTime::try_from(timestamp.clone()) {
                prop_assert_eq!(Timestamp::from(system_time), timestamp);
            }
        }
    }

    #[cfg(feature = "std")]
    #[test]
    fn check_timestamp_negative_seconds() {
        // Representative tests for the case of timestamps before the UTC Epoch time:
        // validate the expected behaviour that "negative second values with fractions
        // must still have non-negative nanos values that count forward in time"
        // https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#google.protobuf.Timestamp
        //
        // To ensure cross-platform compatibility, all nanosecond values in these
        // tests are in minimum 100 ns increments.  This does not affect the general
        // character of the behaviour being tested, but ensures that the tests are
        // valid for both POSIX (1 ns precision) and Windows (100 ns precision).
        assert_eq!(
            Timestamp::from(UNIX_EPOCH - Duration::new(1_001, 0)),
            Timestamp {
                seconds: -1_001,
                nanos: 0
            }
        );
        assert_eq!(
            Timestamp::from(UNIX_EPOCH - Duration::new(0, 999_999_900)),
            Timestamp {
                seconds: -1,
                nanos: 100
            }
        );
        assert_eq!(
            Timestamp::from(UNIX_EPOCH - Duration::new(2_001_234, 12_300)),
            Timestamp {
                seconds: -2_001_235,
                nanos: 999_987_700
            }
        );
        assert_eq!(
            Timestamp::from(UNIX_EPOCH - Duration::new(768, 65_432_100)),
            Timestamp {
                seconds: -769,
                nanos: 934_567_900
            }
        );
    }

    #[cfg(all(unix, feature = "std"))]
    #[test]
    fn check_timestamp_negative_seconds_1ns() {
        // UNIX-only test cases with 1 ns precision
        assert_eq!(
            Timestamp::from(UNIX_EPOCH - Duration::new(0, 999_999_999)),
            Timestamp {
                seconds: -1,
                nanos: 1
            }
        );
        assert_eq!(
            Timestamp::from(UNIX_EPOCH - Duration::new(1_234_567, 123)),
            Timestamp {
                seconds: -1_234_568,
                nanos: 999_999_877
            }
        );
        assert_eq!(
            Timestamp::from(UNIX_EPOCH - Duration::new(890, 987_654_321)),
            Timestamp {
                seconds: -891,
                nanos: 12_345_679
            }
        );
    }

    #[test]
    fn check_duration_normalize() {
        #[rustfmt::skip] // Don't mangle the table formatting.
        let cases = [
            // --- Table of test cases ---
            //        test seconds      test nanos  expected seconds  expected nanos
            (line!(),            0,              0,                0,              0),
            (line!(),            1,              1,                1,              1),
            (line!(),           -1,             -1,               -1,             -1),
            (line!(),            0,    999_999_999,                0,    999_999_999),
            (line!(),            0,   -999_999_999,                0,   -999_999_999),
            (line!(),            0,  1_000_000_000,                1,              0),
            (line!(),            0, -1_000_000_000,               -1,              0),
            (line!(),            0,  1_000_000_001,                1,              1),
            (line!(),            0, -1_000_000_001,               -1,             -1),
            (line!(),           -1,              1,                0,   -999_999_999),
            (line!(),            1,             -1,                0,    999_999_999),
            (line!(),           -1,  1_000_000_000,                0,              0),
            (line!(),            1, -1_000_000_000,                0,              0),
            (line!(), i64::MIN    ,              0,     i64::MIN    ,              0),
            (line!(), i64::MIN + 1,              0,     i64::MIN + 1,              0),
            (line!(), i64::MIN    ,              1,     i64::MIN + 1,   -999_999_999),
            (line!(), i64::MIN    ,  1_000_000_000,     i64::MIN + 1,              0),
            (line!(), i64::MIN    , -1_000_000_000,     i64::MIN    ,   -999_999_999),
            (line!(), i64::MIN + 1, -1_000_000_000,     i64::MIN    ,              0),
            (line!(), i64::MIN + 2, -1_000_000_000,     i64::MIN + 1,              0),
            (line!(), i64::MIN    , -1_999_999_998,     i64::MIN    ,   -999_999_999),
            (line!(), i64::MIN + 1, -1_999_999_998,     i64::MIN    ,   -999_999_998),
            (line!(), i64::MIN + 2, -1_999_999_998,     i64::MIN + 1,   -999_999_998),
            (line!(), i64::MIN    , -1_999_999_999,     i64::MIN    ,   -999_999_999),
            (line!(), i64::MIN + 1, -1_999_999_999,     i64::MIN    ,   -999_999_999),
            (line!(), i64::MIN + 2, -1_999_999_999,     i64::MIN + 1,   -999_999_999),
            (line!(), i64::MIN    , -2_000_000_000,     i64::MIN    ,   -999_999_999),
            (line!(), i64::MIN + 1, -2_000_000_000,     i64::MIN    ,   -999_999_999),
            (line!(), i64::MIN + 2, -2_000_000_000,     i64::MIN    ,              0),
            (line!(), i64::MIN    ,   -999_999_998,     i64::MIN    ,   -999_999_998),
            (line!(), i64::MIN + 1,   -999_999_998,     i64::MIN + 1,   -999_999_998),
            (line!(), i64::MAX    ,              0,     i64::MAX    ,              0),
            (line!(), i64::MAX - 1,              0,     i64::MAX - 1,              0),
            (line!(), i64::MAX    ,             -1,     i64::MAX - 1,    999_999_999),
            (line!(), i64::MAX    ,  1_000_000_000,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 1,  1_000_000_000,     i64::MAX    ,              0),
            (line!(), i64::MAX - 2,  1_000_000_000,     i64::MAX - 1,              0),
            (line!(), i64::MAX    ,  1_999_999_998,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 1,  1_999_999_998,     i64::MAX    ,    999_999_998),
            (line!(), i64::MAX - 2,  1_999_999_998,     i64::MAX - 1,    999_999_998),
            (line!(), i64::MAX    ,  1_999_999_999,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 1,  1_999_999_999,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 2,  1_999_999_999,     i64::MAX - 1,    999_999_999),
            (line!(), i64::MAX    ,  2_000_000_000,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 1,  2_000_000_000,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 2,  2_000_000_000,     i64::MAX    ,              0),
            (line!(), i64::MAX    ,    999_999_998,     i64::MAX    ,    999_999_998),
            (line!(), i64::MAX - 1,    999_999_998,     i64::MAX - 1,    999_999_998),
        ];

        for case in cases.iter() {
            let mut test_duration = crate::Duration {
                seconds: case.1,
                nanos: case.2,
            };
            test_duration.normalize();

            assert_eq!(
                test_duration,
                crate::Duration {
                    seconds: case.3,
                    nanos: case.4,
                },
                "test case on line {} doesn't match",
                case.0,
            );
        }
    }

    #[cfg(feature = "std")]
    #[test]
    fn check_timestamp_normalize() {
        // Make sure that `Timestamp::normalize` behaves correctly on and near overflow.
        #[rustfmt::skip] // Don't mangle the table formatting.
        let cases = [
            // --- Table of test cases ---
            //        test seconds      test nanos  expected seconds  expected nanos
            (line!(),            0,              0,                0,              0),
            (line!(),            1,              1,                1,              1),
            (line!(),           -1,             -1,               -2,    999_999_999),
            (line!(),            0,    999_999_999,                0,    999_999_999),
            (line!(),            0,   -999_999_999,               -1,              1),
            (line!(),            0,  1_000_000_000,                1,              0),
            (line!(),            0, -1_000_000_000,               -1,              0),
            (line!(),            0,  1_000_000_001,                1,              1),
            (line!(),            0, -1_000_000_001,               -2,    999_999_999),
            (line!(),           -1,              1,               -1,              1),
            (line!(),            1,             -1,                0,    999_999_999),
            (line!(),           -1,  1_000_000_000,                0,              0),
            (line!(),            1, -1_000_000_000,                0,              0),
            (line!(), i64::MIN    ,              0,     i64::MIN    ,              0),
            (line!(), i64::MIN + 1,              0,     i64::MIN + 1,              0),
            (line!(), i64::MIN    ,              1,     i64::MIN    ,              1),
            (line!(), i64::MIN    ,  1_000_000_000,     i64::MIN + 1,              0),
            (line!(), i64::MIN    , -1_000_000_000,     i64::MIN    ,              0),
            (line!(), i64::MIN + 1, -1_000_000_000,     i64::MIN    ,              0),
            (line!(), i64::MIN + 2, -1_000_000_000,     i64::MIN + 1,              0),
            (line!(), i64::MIN    , -1_999_999_998,     i64::MIN    ,              0),
            (line!(), i64::MIN + 1, -1_999_999_998,     i64::MIN    ,              0),
            (line!(), i64::MIN + 2, -1_999_999_998,     i64::MIN    ,              2),
            (line!(), i64::MIN    , -1_999_999_999,     i64::MIN    ,              0),
            (line!(), i64::MIN + 1, -1_999_999_999,     i64::MIN    ,              0),
            (line!(), i64::MIN + 2, -1_999_999_999,     i64::MIN    ,              1),
            (line!(), i64::MIN    , -2_000_000_000,     i64::MIN    ,              0),
            (line!(), i64::MIN + 1, -2_000_000_000,     i64::MIN    ,              0),
            (line!(), i64::MIN + 2, -2_000_000_000,     i64::MIN    ,              0),
            (line!(), i64::MIN    ,   -999_999_998,     i64::MIN    ,              0),
            (line!(), i64::MIN + 1,   -999_999_998,     i64::MIN    ,              2),
            (line!(), i64::MAX    ,              0,     i64::MAX    ,              0),
            (line!(), i64::MAX - 1,              0,     i64::MAX - 1,              0),
            (line!(), i64::MAX    ,             -1,     i64::MAX - 1,    999_999_999),
            (line!(), i64::MAX    ,  1_000_000_000,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 1,  1_000_000_000,     i64::MAX    ,              0),
            (line!(), i64::MAX - 2,  1_000_000_000,     i64::MAX - 1,              0),
            (line!(), i64::MAX    ,  1_999_999_998,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 1,  1_999_999_998,     i64::MAX    ,    999_999_998),
            (line!(), i64::MAX - 2,  1_999_999_998,     i64::MAX - 1,    999_999_998),
            (line!(), i64::MAX    ,  1_999_999_999,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 1,  1_999_999_999,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 2,  1_999_999_999,     i64::MAX - 1,    999_999_999),
            (line!(), i64::MAX    ,  2_000_000_000,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 1,  2_000_000_000,     i64::MAX    ,    999_999_999),
            (line!(), i64::MAX - 2,  2_000_000_000,     i64::MAX    ,              0),
            (line!(), i64::MAX    ,    999_999_998,     i64::MAX    ,    999_999_998),
            (line!(), i64::MAX - 1,    999_999_998,     i64::MAX - 1,    999_999_998),
        ];

        for case in cases.iter() {
            let mut test_timestamp = crate::Timestamp {
                seconds: case.1,
                nanos: case.2,
            };
            test_timestamp.normalize();

            assert_eq!(
                test_timestamp,
                crate::Timestamp {
                    seconds: case.3,
                    nanos: case.4,
                },
                "test case on line {} doesn't match",
                case.0,
            );
        }
    }
}