#!/usr/bin/env bash
# Validates conventional commit format: type(scope): description
# Types: feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert
# Optional ! for breaking changes: feat(api)!: change response format
# Merge commits and fixup/squash commits are always allowed.

msg_file="$1"
msg=$(head -1 "$msg_file")

# Allow merge commits
if echo "$msg" | grep -qE '^Merge '; then
	exit 0
fi

# Allow fixup/squash commits
if echo "$msg" | grep -qE '^(fixup|squash)! '; then
	exit 0
fi

pattern='^(feat|fix|docs|style|refactor|perf|test|build|ci|chore|revert)(\([a-zA-Z0-9_/-]+\))?!?: .+'

if ! echo "$msg" | grep -qE "$pattern"; then
	echo "ERROR: Commit message does not follow Conventional Commits format."
	echo ""
	echo "  Expected: <type>(<scope>): <description>"
	echo "  Types:    feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert"
	echo "  Example:  feat(auth): add OAuth2 support"
	echo "  Breaking: feat(api)!: change response format"
	echo ""
	echo "  Your message: $msg"
	exit 1
fi