Function format_duration 

pub fn format_duration(duration: &Duration) -> String

Formats a chrono::Duration into a standardized “HH:MM” string.

This function converts a time duration into a human-readable format suitable for display in reports, tables, and user interfaces. It ensures consistent formatting across the entire application.

Formatting Rules

• Hours: Always displayed with at least 2 digits (zero-padded)
• Minutes: Always displayed with exactly 2 digits (zero-padded)
• Seconds: Not displayed (rounded to nearest minute)
• Negative: Treated as zero duration (“00:00”)
• Overflow: Large durations handled gracefully

Algorithm

1. Extract total hours from the duration
2. Extract remaining minutes (after removing full hours)
3. Clamp negative values to zero
4. Format with zero-padding

Arguments

• duration - A reference to the chrono::Duration to format

Returns

A String in “HH:MM” format representing the duration.

Examples

use kasl::libs::formatter::format_duration;
use chrono::Duration;

// Standard durations
assert_eq!(format_duration(&Duration::hours(8)), "08:00");
assert_eq!(format_duration(&Duration::minutes(90)), "01:30");
assert_eq!(format_duration(&Duration::minutes(45)), "00:45");

// Edge cases
assert_eq!(format_duration(&Duration::zero()), "00:00");
assert_eq!(format_duration(&Duration::hours(-1)), "00:00");
assert_eq!(format_duration(&Duration::hours(24)), "24:00");

Performance Notes

This function is designed for frequent use and has minimal overhead:

• Single allocation for the result string
• Simple arithmetic operations only
• No complex parsing or validation

Thread Safety

This function is pure and thread-safe. It can be called concurrently from multiple threads without synchronization.