#!/bin/bash
# ABOUTME: Commit-msg hook that validates commit messages follow conventional commit format.
# ABOUTME: Install with `make install-hooks`.

set -e

COMMIT_MSG_FILE="$1"
COMMIT_MSG=$(cat "$COMMIT_MSG_FILE")

# Pattern for conventional commits: type(scope)?: message
# Types: feat, fix, chore, docs, style, refactor, perf, test, build, ci
PATTERN='^(feat|fix|chore|docs|style|refactor|perf|test|build|ci)(\([[:alnum:]_-]+\))?!?:.+$'

# Get the first line (subject) of the commit message
FIRST_LINE=$(echo "$COMMIT_MSG" | head -n 1)

# Skip validation for merge commits
if echo "$FIRST_LINE" | grep -qE '^Merge '; then
    exit 0
fi

# Skip validation for revert commits
if echo "$FIRST_LINE" | grep -qE '^Revert '; then
    exit 0
fi

if ! echo "$FIRST_LINE" | grep -qE "$PATTERN"; then
    echo "Error: Invalid commit message format."
    echo ""
    echo "Commit message: '$FIRST_LINE'"
    echo ""
    echo "Expected format: <type>(<scope>)?: <description>"
    echo ""
    echo "Valid types:"
    echo "  feat     - A new feature"
    echo "  fix      - A bug fix"
    echo "  chore    - Maintenance tasks"
    echo "  docs     - Documentation changes"
    echo "  style    - Code style changes (formatting, etc.)"
    echo "  refactor - Code refactoring"
    echo "  perf     - Performance improvements"
    echo "  test     - Adding or updating tests"
    echo "  build    - Build system changes"
    echo "  ci       - CI configuration changes"
    echo ""
    echo "Examples:"
    echo "  feat: add user authentication"
    echo "  fix(auth): resolve token expiration issue"
    echo "  chore(deps): update dependencies"
    echo "  feat!: breaking change in API"
    exit 1
fi

echo "Commit message format valid."