#!/bin/sh
#
# Refuses AI attribution in commit messages.
#
# This repo is public, so history is the first thing an outside contributor
# sees. Attribution cannot be removed retroactively without rewriting every
# commit after it, and clones have already copied it.
#
# Enable after cloning:
#
#     git config core.hooksPath .githooks
#
# The executable bit is committed (mode 100755), so a clone gets a runnable
# hook. Git still will not enable a repo's hooks on its own — deliberately, so
# that cloning cannot execute code from the remote — hence the one command.

msg_file="$1"

# Co-author trailers naming an assistant.
if grep -qiE 'co-?authored-?by:[[:space:]]*.*(claude|anthropic|copilot|cursor|codex|chatgpt|gpt-|gemini|aider|devin|llm|\bai\b)' "$msg_file"; then
	echo "REFUSED: AI co-author trailer in commit message." >&2
	exit 1
fi

# Generated-with footers and the robot emoji.
if grep -qiE 'generated with|written by (claude|an? ai)|🤖' "$msg_file"; then
	echo "REFUSED: AI attribution in commit message." >&2
	exit 1
fi

exit 0