// Copyright (c) 2014-2018, b3log.org & hacpai.com
//
// 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 util includes common utilities.
package util

import (
	"errors"
	"net"
)

type mynet struct{}

// Network utilities.
var Net = mynet{}

// LocalIP gets the first NIC's IP address.
func (*mynet) LocalIP() (string, error) {
	addrs, err := net.InterfaceAddrs()

	if nil != err {
		return "", err
	}

	for _, address := range addrs {
		if ipnet, ok := address.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
			if nil != ipnet.IP.To4() {
				return ipnet.IP.String(), nil
			}
		}
	}

	return "", errors.New("can't get local IP")
}