execution_time/

time.rs

use crate::{FormatFloatValue, FormatIntegerValue, RoundFloat, Unit};
use std::time::Duration;

// Constants for seconds in a day, an hour, and a minute to improve readability.
const SECONDS_IN_DAY: f64 = 86400.0;
const SECONDS_IN_HOUR: f64 = 3600.0;
const SECONDS_IN_MINUTE: f64 = 60.0;

// Set a small margin of error
const EPSILON: f64 = 1e-10;

/// Represents a time duration split into days, hours, minutes, and seconds.
///
/// This struct holds the components of a time duration for formatting and display purposes.
#[derive(Debug, Default, PartialEq)]
pub struct Time {
    pub days: u64,
    pub hours: u8,
    pub minutes: u8,
    pub seconds: f64,
}

impl Time {
    /// Creates a `Time` struct from a `Duration`.
    ///
    /// `Duration` represents a span of time composed of whole seconds and a
    /// fractional part represented in nanoseconds.  
    ///
    /// This function converts
    /// that representation into days, hours, minutes, and seconds.
    pub fn new(duration: Duration) -> Time {
        let dur_secs: f64 = duration.as_secs_f64();

        let remaining_day = dur_secs % SECONDS_IN_DAY;
        let remaining_hour = remaining_day % SECONDS_IN_HOUR;

        let days = (dur_secs / SECONDS_IN_DAY).floor() as u64;
        let hours = (remaining_day / SECONDS_IN_HOUR).floor() as u8;
        let minutes = (remaining_hour / SECONDS_IN_MINUTE).floor() as u8;
        let seconds = (remaining_hour % SECONDS_IN_MINUTE).round_float(9);

        Time {
            days,
            hours,
            minutes,
            seconds,
        }
    }

    /// Formats the time duration into a human-readable string.
    ///
    /// This method combines the time components (days, hours, minutes, seconds) into a
    /// single, formatted string.  It includes only non-zero components, except for seconds,
    /// which are always included.
    ///
    /// # Returns
    ///
    /// A formatted time string.
    pub fn format_time(&self) -> String {
        let mut parts = Vec::new();

        // Add days to the output if they are greater than 0.
        if self.days > 0 {
            parts.push(self.days.format_unit(Unit::Day));
        }

        // Add hours to the output if they are greater than 0, or if days have already been added.
        if self.hours > 0 || !parts.is_empty() {
            parts.push(self.hours.format_unit(Unit::Hour));
        }

        // Add minutes to the output if they are greater than 0, or if hours or days have already been added.
        if self.minutes > 0 || !parts.is_empty() {
            parts.push(self.minutes.format_unit(Unit::Minute));
        }

        let decimal: usize = self.calculate_decimal();

        // Always add seconds to the output.
        parts.push(self.seconds.format_float_unit(decimal, Unit::Second));

        parts.join(", ")
    }

    fn calculate_decimal(&self) -> usize {
        let sec = self.seconds;

        if sec < EPSILON {
            // Handles the case where 'sec' is approximately zero
            1
        } else if sec >= 1.0 {
            3
        } else if sec >= 0.001 {
            6
        } else {
            9
        }
    }
}

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

    #[test]
    fn time_new() {
        let duration = Duration::from_secs(86400 + 3600 + 60 + 1); // 1 day, 1 hour, 1 minute, 1 second
        let time = Time::new(duration);
        assert_eq!(time.days, 1);
        assert_eq!(time.hours, 1);
        assert_eq!(time.minutes, 1);
        assert_eq!(time.seconds, 1.0);

        let duration = Duration::from_secs_f64(3661.5); // 1 hour, 1 minute, 1.5 seconds
        let time = Time::new(duration);
        assert_eq!(time.days, 0);
        assert_eq!(time.hours, 1);
        assert_eq!(time.minutes, 1);
        assert_eq!(time.seconds, 1.5);

        let duration = Duration::from_secs(0);
        let time = Time::new(duration);
        assert_eq!(time.days, 0);
        assert_eq!(time.hours, 0);
        assert_eq!(time.minutes, 0);
        assert_eq!(time.seconds, 0.0);

        let duration = Duration::from_secs_f64(SECONDS_IN_DAY * 2.5);
        let time = Time::new(duration);
        assert_eq!(time.days, 2);
        assert_eq!(time.hours, 12);
        assert_eq!(time.minutes, 0);
        assert_eq!(time.seconds, 0.0);
    }

    #[test]
    fn times_format() {
        let time = Time {
            days: 1,
            hours: 2,
            minutes: 3,
            seconds: 4.567,
        };
        assert_eq!(
            time.format_time(),
            "1 day, 2 hours, 3 minutes, 4.567 seconds"
        );

        let time = Time {
            days: 0,
            hours: 2,
            minutes: 3,
            seconds: 4.567,
        };
        assert_eq!(time.format_time(), "2 hours, 3 minutes, 4.567 seconds");

        let time = Time {
            days: 0,
            hours: 0,
            minutes: 3,
            seconds: 4.567,
        };
        assert_eq!(time.format_time(), "3 minutes, 4.567 seconds");

        let time = Time {
            days: 0,
            hours: 0,
            minutes: 0,
            seconds: 4.567,
        };
        assert_eq!(time.format_time(), "4.567 seconds");

        let time = Time {
            days: 1,
            hours: 0,
            minutes: 0,
            seconds: 0.0,
        };

        assert_eq!(time.format_time(), "1 day, 0 hour, 0 minute, 0.0 second");

        let time = Time {
            days: 1,
            hours: 2,
            minutes: 0,
            seconds: 0.0,
        };
        assert_eq!(time.format_time(), "1 day, 2 hours, 0 minute, 0.0 second");
    }

    #[test]
    fn format_time_default() {
        let time = Time {
            days: 0,
            hours: 0,
            minutes: 0,
            seconds: 0.0,
        };
        let time_default = Time::default();

        assert_eq!(time, time_default);
        assert_eq!(time.format_time(), "0.0 second");
    }
}