execution_time/

lib.rs

mod time;
mod traits;

pub use self::{time::*, traits::*};
use std::time::Instant;

// Constant for the number of decimal places to use when formatting seconds
const DECIMAL: usize = 4;

/// Measures the execution time of a code block.
///
/// This struct provides methods to start a timer and print the elapsed time
/// in a user-friendly format.
pub struct ExecutionTime {
    start_time: Instant,
}

impl ExecutionTime {
    /// Starts a new stopwatch.
    ///
    /// This function initializes the timer by recording the current time.
    ///
    /// # Returns
    ///
    /// A new `ExecutionTime` instance.
    pub fn start() -> Self {
        Self {
            start_time: Instant::now(),
        }
    }

    /// Splits the total elapsed seconds into days, hours, minutes, and seconds.
    ///
    /// This method takes a floating-point number of seconds and breaks it down
    /// into human-readable units (days, hours, minutes, and seconds).
    ///
    /// # Arguments
    ///
    /// * `total_seconds` - The total elapsed time in seconds.
    ///
    /// # Returns
    ///
    /// A `Time` struct containing the split time values.
    fn split_time(&self, total_seconds: f64) -> Time {
        // Constants for seconds in a day and an hour to improve readability
        const SECONDS_IN_DAY: f64 = 86400.0;
        const SECONDS_IN_HOUR: f64 = 3600.0;
        const SECONDS_IN_MINUTE: f64 = 60.0;

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

        let days = (total_seconds / 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(DECIMAL);

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

    /// Calculates the elapsed time since the stopwatch was started.
    ///
    /// This method calculates the elapsed time, formats it into a readable string.
    ///
    /// The output format depends on whether the elapsed time is less than or
    /// greater than 60 seconds.
    pub fn get_elapsed_time(&self) -> String {
        let total_seconds = self.start_time.elapsed().as_secs_f64();
        let time_total = total_seconds.format_unit(DECIMAL, "second", "seconds");

        // Format the output based on whether the elapsed time is greater than or equal to 60 seconds
        if total_seconds >= 60.0 {
            let time_dhms = self.split_time(total_seconds).format_time();
            format!("{time_dhms} ({time_total})")
        } else {
            time_total
        }
    }

    /// Calculates and prints the elapsed time since the stopwatch was started.
    ///
    /// This method calculates the elapsed time, formats it into a readable string,
    /// and prints it to the console.
    ///
    /// The output format depends on whether the elapsed time is less than or
    /// greater than 60 seconds.
    pub fn print_elapsed_time(&self) {
        println!("Elapsed time: {}", self.get_elapsed_time());
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    type Error = Box<dyn std::error::Error>;

    #[test]
    /// `cargo test -- --show-output elapsed_time_less_than_minute`
    fn elapsed_time_less_than_minute() -> Result<(), Error> {
        let timer = ExecutionTime::start();
        let total_seconds: f64 = 0.01516345;

        let formatted_total_seconds = "0.0152 second";

        let time_dhms = timer.split_time(total_seconds).format_time();
        let time_total = total_seconds.format_unit(DECIMAL, "second", "seconds");

        let formatted_output = if total_seconds >= 60.0 {
            format!("{time_dhms} ({time_total})")
        } else {
            time_total
        };

        println!("total_seconds: {total_seconds}");
        println!("formatted_total_seconds: {formatted_total_seconds}");
        println!("formatted_output: {formatted_output}\n");

        assert_eq!(formatted_total_seconds, formatted_output);

        Ok(())
    }

    #[test]
    /// `cargo test -- --show-output elapsed_time_more_than_minute`
    fn elapsed_time_more_than_minute() -> Result<(), Error> {
        let timer = ExecutionTime::start();
        let total_seconds: f64 = 65.080012345;

        let formatted_total_seconds = "1 minute, 5.0800 seconds (65.0800 seconds)";

        let time_dhms = timer.split_time(total_seconds).format_time();
        let time_total = total_seconds.format_unit(DECIMAL, "second", "seconds");

        let formatted_output = if total_seconds >= 60.0 {
            format!("{time_dhms} ({time_total})")
        } else {
            time_total
        };

        println!("total_seconds: {total_seconds}");
        println!("formatted_total_seconds: {formatted_total_seconds}");
        println!("formatted_output: {formatted_output}\n");

        assert_eq!(formatted_total_seconds, formatted_output);

        Ok(())
    }

    #[test]
    /// `cargo test -- --show-output elapsed_time_more_than_hour`
    fn elapsed_time_more_than_hour() -> Result<(), Error> {
        let timer = ExecutionTime::start();
        let total_seconds: f64 = 3700.05689123;

        let formatted_total_seconds = "1 hour, 1 minute, 40.0569 seconds (3700.0569 seconds)";

        let time_dhms = timer.split_time(total_seconds).format_time();
        let time_total = total_seconds.format_unit(DECIMAL, "second", "seconds");

        let formatted_output = if total_seconds >= 60.0 {
            format!("{time_dhms} ({time_total})")
        } else {
            time_total
        };

        println!("total_seconds: {total_seconds}");
        println!("formatted_total_seconds: {formatted_total_seconds}");
        println!("formatted_output: {formatted_output}\n");

        assert_eq!(formatted_total_seconds, formatted_output);

        Ok(())
    }

    #[test]
    /// `cargo test -- --show-output elapsed_time_more_than_day`
    fn elapsed_time_more_than_day() -> Result<(), Error> {
        let timer = ExecutionTime::start();
        let total_seconds: f64 = 86400.0 + 3700.03;

        let formatted_total_seconds =
            "1 day, 1 hour, 1 minute, 40.0300 seconds (90100.0300 seconds)";

        let time_dhms = timer.split_time(total_seconds).format_time();
        let time_total = total_seconds.format_unit(DECIMAL, "second", "seconds");

        let formatted_output = if total_seconds >= 60.0 {
            format!("{time_dhms} ({time_total})")
        } else {
            time_total
        };

        println!("total_seconds: {total_seconds}");
        println!("formatted_total_seconds: {formatted_total_seconds}");
        println!("formatted_output: {formatted_output}\n");

        assert_eq!(formatted_total_seconds, formatted_output);

        Ok(())
    }
}