// Copyright 2019 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package internal

import (
	"strings"
	"sync"

	"github.com/gobwas/glob"
)

var (
	globCache = make(map[string]glob.Glob)
	globMu    sync.RWMutex
)

func GetGlob(pattern string) (glob.Glob, error) {
	var g glob.Glob

	globMu.RLock()
	g, found := globCache[pattern]
	globMu.RUnlock()
	if !found {
		var err error
		g, err = glob.Compile(strings.ToLower(pattern), '/')
		if err != nil {
			return nil, err
		}

		globMu.Lock()
		globCache[pattern] = g
		globMu.Unlock()
	}

	return g, nil

}