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    use std::{convert::TryInto, ops::Add, time::Duration};

    use chrono::SubsecRound as _;

    use crate::Error as LimitationError;

    /// A report for a given key containing the limit status.
    #[derive(Debug, Clone)]
    pub struct Status {
        pub(crate) limit: usize,
        pub(crate) remaining: usize,
        pub(crate) reset_epoch_utc: usize,
    }

    impl Status {
        /// Constructs status limit status from parts.
        #[must_use]
        pub(crate) fn new(count: usize, limit: usize, reset_epoch_utc: usize) -> Self {
            let remaining = if count >= limit { 0 } else { limit - count };

            Status {
                limit,
                remaining,
                reset_epoch_utc,
            }
        }

        /// Returns the maximum number of requests allowed in the current period.
        #[must_use]
        pub fn limit(&self) -> usize {
            self.limit
        }

        /// Returns how many requests are left in the current period.
        #[must_use]
        pub fn remaining(&self) -> usize {
            self.remaining
        }

        /// Returns a UNIX timestamp in UTC approximately when the next period will begin.
        #[must_use]
        pub fn reset_epoch_utc(&self) -> usize {
            self.reset_epoch_utc
        }

        pub(crate) fn epoch_utc_plus(duration: Duration) -> Result<usize, LimitationError> {
            match chrono::Duration::from_std(duration) {
                Ok(value) => Ok(chrono::Utc::now()
                    .add(value)
                    .round_subsecs(0)
                    .timestamp()
                    .try_into()
                    .unwrap_or(0)),

                Err(_) => Err(LimitationError::Other(
                    "Source duration value is out of range for the target type".to_string(),
                )),
            }
        }
    }

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

        #[test]
        fn test_create_status() {
            let status = Status {
                limit: 100,
                remaining: 0,
                reset_epoch_utc: 1000,
            };

            assert_eq!(status.limit(), 100);
            assert_eq!(status.remaining(), 0);
            assert_eq!(status.reset_epoch_utc(), 1000);
        }

        #[test]
        fn test_build_status() {
            let count = 200;
            let limit = 100;
            let status = Status::new(count, limit, 2000);
            assert_eq!(status.limit(), limit);
            assert_eq!(status.remaining(), 0);
            assert_eq!(status.reset_epoch_utc(), 2000);
        }

        #[test]
        fn test_build_status_limit() {
            let limit = 100;
            let status = Status::new(0, limit, 2000);
            assert_eq!(status.limit(), limit);
            assert_eq!(status.remaining(), limit);
            assert_eq!(status.reset_epoch_utc(), 2000);
        }

        #[test]
        fn test_epoch_utc_plus_zero() {
            let duration = Duration::from_secs(0);
            let seconds = Status::epoch_utc_plus(duration).unwrap();
            assert!(seconds as u64 >= duration.as_secs());
        }

        #[test]
        fn test_epoch_utc_plus() {
            let duration = Duration::from_secs(10);
            let seconds = Status::epoch_utc_plus(duration).unwrap();
            assert!(seconds as u64 >= duration.as_secs() + 10);
        }

        #[test]
        #[should_panic = "Source duration value is out of range for the target type"]
        fn test_epoch_utc_plus_overflow() {
            let duration = Duration::from_secs(10000000000000000000);
            Status::epoch_utc_plus(duration).unwrap();
        }
    }