calc_downtime.py

#!/usr/bin/env python3
import subprocess
import datetime
from collections import Counter

def get_commit_hours(repo_path="."):
    # Get all commit timestamps in ISO 8601 format
    result = subprocess.run(
        ["git", "-C", repo_path, "log", "--pretty=format:%ci"],
        capture_output=True, text=True, check=True
    )
    commit_times = result.stdout.strip().split("\n")
    
    hours = []
    for time_str in commit_times:
        try:
            dt = datetime.datetime.strptime(time_str, "%Y-%m-%d %H:%M:%S %z")
            hours.append(dt.hour)
        except ValueError:
            continue  # skip invalid entries
    return hours

def find_least_active_hours(hours):
    counter = Counter(hours)
    total_commits = sum(counter.values())
    activity = [(hour, counter[hour], counter[hour]/total_commits*100) for hour in range(24)]
    activity.sort(key=lambda x: x[1])  # Sort by least activity
    return activity

def print_activity_summary(activity):
    print("Commit activity by hour (UTC):")
    for hour, count, pct in activity:
        print(f"{hour:02d}:00 - {count:4d} commits ({pct:5.2f}%)")

    least_active = activity[0][0]
    print(f"\n💤 Least active hour: {least_active:02d}:00 UTC")
    print(f"Suggested build window: around {least_active:02d}:00 UTC\n")

if __name__ == "__main__":
    repo = "."  # current directory by default
    hours = get_commit_hours(repo)
    if not hours:
        print("No commits found.")
    else:
        activity = find_least_active_hours(hours)
        print_activity_summary(activity)