stopwatch.py

"""Run an interactive terminal stopwatch.

Usage: python3.14 stopwatch.py
Press Enter for a lap, :t for total time, :s to pause, or :q to quit.
"""

from __future__ import annotations

import time


def format_duration(seconds: float) -> str:
    """Format a duration as an English hours/minutes/seconds string."""
    total = int(seconds)
    hours, remainder = divmod(total, 3600)
    minutes, secs = divmod(remainder, 60)
    return f"{hours} hours {minutes} minutes {secs} seconds"


def main() -> int:
    started = lap_started = time.monotonic()
    paused_total = 0.0
    print("Stopwatch\n")
    print("Commands: :q quit, :s pause, :t show total time")
    while True:
        try:
            command = input("Press Enter or enter a command: ").strip()
        except (EOFError, KeyboardInterrupt):
            print()
            return 0
        now = time.monotonic()
        if command == ":q":
            return 0
        if command == ":t":
            print(f"Elapsed: {format_duration(now - started - paused_total)}")
        elif command == ":s":
            paused_at = time.monotonic()
            input("Press Enter to resume the stopwatch")
            pause = time.monotonic() - paused_at
            paused_total += pause
            lap_started += pause
        else:
            print(f"Lap: {format_duration(now - lap_started)}")
            lap_started = now


if __name__ == "__main__":
    raise SystemExit(main())