#!/usr/bin/env bash
# .git/hooks/commit-msg
# Lints commit messages to enforce Conventional Commits format
# (you can customize the regex or replace with commitlint, etc.)

COMMIT_MSG_FILE="$1"

# Skip empty messages or merge/revert commits (Git handles those)
if [[ -z "$(cat "$COMMIT_MSG_FILE")" ]]; then
    echo "Commit message cannot be empty."
    exit 1
fi

# Basic Conventional Commits regex:
# type[(scope)]: description
# Allowed types: feat, fix, chore, docs, test, style, refactor, perf, build, ci, revert
if ! head -n1 "$COMMIT_MSG_FILE" | grep -qE '^(feat|fix|chore|docs|test|style|refactor|perf|build|ci|revert)(\([a-z0-9-]+\))?!?: .+'; then
    echo "Invalid commit message format."
    echo "   Use Conventional Commits: <type>[optional scope]: <description>"
    echo "   Valid types: feat, fix, chore, docs, test, style, refactor, perf, build, ci, revert"
    echo "   Example: feat(api): add user authentication"
    echo "   Full spec: https://www.conventionalcommits.org"
    exit 1
fi

# Optional: enforce reasonable length
if [[ $(head -n1 "$COMMIT_MSG_FILE" | wc -c) -gt 100 ]]; then
    echo "Commit message subject is too long (max 100 chars recommended)."
    exit 1
fi

echo "Commit message looks good!"
exit 0