// Copyright 2020 Douyu
//
// 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 xnet

import (
	"errors"
	"fmt"
	"net"
)

// GetLocalIP ...
func GetLocalIP() (string, error) {
	addrs, err := net.InterfaceAddrs()
	if err != nil {
		return "", err
	}
	for _, addr := range addrs {
		if ipnet, ok := addr.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
			if ipnet.IP.To4() != nil {
				return ipnet.IP.String(), nil
			}
		}
	}
	return "", errors.New("unable to determine locla ip")
}

// GetLocalIP ...
func GetLocalMainIP() (string, int, error) {
	// UDP Connect, no handshake
	conn, err := net.Dial("udp", "8.8.8.8:8")
	if err != nil {
		return "", 0, err
	}
	defer conn.Close()
	localAddr := conn.LocalAddr().(*net.UDPAddr)

	return localAddr.IP.String(), localAddr.Port, nil
}

// GetMacAddrs ...
func GetMacAddrs() (macAddrs []string) {
	netInterfaces, err := net.Interfaces()
	if err != nil {
		fmt.Printf("fail to get net interfaces: %v", err)
		return macAddrs
	}

	for _, netInterface := range netInterfaces {
		macAddr := netInterface.HardwareAddr.String()
		if len(macAddr) == 0 {
			continue
		}

		macAddrs = append(macAddrs, macAddr)
	}
	return macAddrs
}

// GetIPs ...
func GetIPs() (ips []string) {
	interfaceAddr, err := net.InterfaceAddrs()
	if err != nil {
		fmt.Printf("fail to get net interface addrs: %v", err)
		return ips
	}

	for _, address := range interfaceAddr {
		ipNet, isValidIPNet := address.(*net.IPNet)
		if isValidIPNet && !ipNet.IP.IsLoopback() {
			if ipNet.IP.To4() != nil {
				ips = append(ips, ipNet.IP.String())
			}
		}
	}
	return ips
}
