#!/usr/bin/env python3
"""Refuse a change to plugin/ that leaves the plugin's version where it was.

Claude Code offers an installed plugin an update only when `version` in
plugin/.claude-plugin/plugin.json changes. A hook change without a new version
never reaches a machine that installed the plugin before it.

Compares what is staged with origin/main, so one bump covers every commit on a
branch. Run by prek on changes under plugin/, or by hand.
"""

import json
import subprocess
import sys

MANIFEST = "plugin/.claude-plugin/plugin.json"
BASE = "origin/main"


def git(*args):
    return subprocess.run(
        ["git", *args], capture_output=True, text=True, check=True
    ).stdout


def version_at(revision):
    return json.loads(git("show", f"{revision}:{MANIFEST}"))["version"]


def main():
    try:
        base = git("merge-base", "HEAD", BASE).strip()
    except subprocess.CalledProcessError:
        print(f"check-plugin-version: no {BASE} to compare with, so not checked")
        return 0
    changed = [
        path
        for path in git("diff", "--cached", "--name-only", base, "--", "plugin/").split()
        if path != MANIFEST
    ]
    if not changed:
        return 0
    before = version_at(base)
    after = version_at("")
    if after != before:
        return 0
    print(
        f"plugin/ changed since {BASE}, but {MANIFEST} is still version {before}.\n"
        "Claude Code offers an update only when the version changes.\n"
        "Changed: " + ", ".join(changed)
    )
    return 1


if __name__ == "__main__":
    sys.exit(main())