How to generate and parse an interactive rebase TODO list in Python

import re
from collections import namedtuple

Commit = namedtuple("Commit", ["hash", "subject"])

def generate_rebase_todo(commits, action="pick"):
    todo_lines = []
    for i, commit in enumerate(commits):
        if i == 0 and action == "reword":
            todo_lines.append(f"reword {commit.hash} {commit.subject}")
        elif action == "squash" and i == len(commits) - 1:
            todo_lines.append(f"squash {commit.hash} {commit.subject}")
        else:
            todo_lines.append(f"pick {commit.hash} {commit.subject}")
    return "\n".join(todo_lines)

def parse_todo(todo_text):
    lines = todo_text.strip().splitlines()
    parsed = []
    for line in lines:
        match = re.match(r"^(pick|reword|squash)\s+([a-f0-9]{7,40})\s+(.*)$", line)
        if match:
            parsed.append({"action": match.group(1), "hash": match.group(2), "subject": match.group(3)})
    return parsed

if __name__ == "__main__":
    commits = [
        Commit("a1b2c3d", "Initial commit"),
        Commit("e4f5a6b", "Add feature X"),
        Commit("7c8d9e0", "Fix bug in feature X"),
    ]

    todo = generate_rebase_todo(commits, action="squash")
    print("Generated TODO:")
    print(todo)
    print("\nParsed TODO:")
    for item in parse_todo(todo):
        print(f"  {item['action']:6s} {item['hash']} {item['subject']}")