How to Make a Git Commit Heatmap by Hour in Python

import re
from collections import Counter
from datetime import datetime

def parse_commits(log_text):
    """Parse git log lines and count commits by (weekday, hour)."""
    pattern = re.compile(r"^Date:\s+(.+)$")
    counts = Counter()
    
    for line in log_text.splitlines():
        match = pattern.match(line)
        if match:
            date_str = match.group(1)
            try:
                dt = datetime.strptime(date_str, "%a %b %d %H:%M:%S %Y %z")
            except ValueError:
                dt = datetime.strptime(date_str, "%a %b %d %H:%M:%S %Y")
            key = (dt.strftime("%A"), dt.hour)
            counts[key] += 1
    return counts

def format_heatmap(counts):
    """Print a compact weekday-by-hour heatmap."""
    days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]
    print(f"{'Day':<10}" + "".join(f"{h:>4}" for h in range(24)))
    for day in days:
        row = f"{day:<10}"
        for hour in range(24):
            row += f"{counts.get((day, hour), 0):>4}"
        print(row)

if __name__ == "__main__":
    sample_log = """Date: Mon Mar 04 09:30:00 2024 +0000
Date: Mon Mar 04 14:15:00 2024 +0000
Date: Tue Mar 05 10:00:00 2024 +0000
Date: Wed Mar 06 09:45:00 2024 +0000
Date: Wed Mar 06 16:20:00 2024 +0000
Date: Fri Mar 08 11:00:00 2024 +0000
Date: Sun Mar 10 20:30:00 2024 +0000
"""
    commits = parse_commits(sample_log)
    format_heatmap(commits)