package utils

import (
	"fmt"
	"github.com/spf13/cast"
	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
	"math/rand"
	"slices"
	"strings"
	"wireguard-dashboard/client"
)

type wireguard struct{}

func Wireguard() wireguard {
	return wireguard{}
}

// GetSpecClient
// @description: 获取指定客户端链接信息
// @receiver wireguard
// @param pk
// @return *wgtypes.Peer
// @return error
func (wireguard) GetSpecClient(pk string) (*wgtypes.Peer, error) {
	device, err := client.WireguardClient.Devices()
	if err != nil {
		return nil, err
	}

	for _, v := range device {
		for _, p := range v.Peers {
			if p.PublicKey.String() == pk {
				return &p, nil
			}
		}
	}

	return nil, nil
}

// GenerateClientIP
// @description: 生成客户端IP
// @receiver wireguard
// @param serverIP
// @param rule
// @return string
func (w wireguard) GenerateClientIP(serverIP, rule string, assignedIPS ...string) string {
	// 再次拆分，只取最后一段
	suffix := w.GetIPSuffix(serverIP)
	prefix := w.GetIPPrefix(serverIP)
	// 如果是随机模式，则需要结尾数字小于等于 255，并且生成的数字不能是已分配当中任何一个
	// 如果是自动模式，只需要是已经分配的最后一位自增
	switch rule {
	case "RANDOM":
		suffix = w.random(assignedIPS...)
	case "AUTO":
		switch len(assignedIPS) {
		case 1:
			suffix = w.GetIPSuffix(assignedIPS[0])
		case 2:
			suffix = w.GetIPSuffix(assignedIPS[1])
		}

		suffix = cast.ToString(cast.ToInt64(suffix) + 1)
	}

	return fmt.Sprintf("%s.%s", prefix, suffix)
}

// random
// @description: 随机模式
// @receiver w
// @param assignedIPS
// @return string
func (w wireguard) random(assignedIPS ...string) string {
	randomNumber := rand.Int63n(256)
	var assuffixIP []int64
	for _, v := range assignedIPS {
		assuffixIP = append(assuffixIP, cast.ToInt64(strings.Split(v, ".")[3]))
	}

	if slices.Contains(assuffixIP, randomNumber) {
		return w.random(assignedIPS...)
	}

	return cast.ToString(randomNumber)
}

// GetIPSuffix
// @description: 获取IP后缀 [10.10.10.23] 这里只获取23
// @receiver w
// @param ip
// @return string
func (w wireguard) GetIPSuffix(ip string) string {
	if strings.Contains(ip, "/") {
		ip = strings.Split(ip, "/")[0]
	}

	// 再次拆分，只取最后一段
	return strings.Split(ip, ".")[3]
}

// GetIPPrefix
// @description: 获取IP前缀[10.10.10.23] 这里只获取 10.10.10
// @receiver w
// @param ip
// @return string
func (w wireguard) GetIPPrefix(ip string) string {
	if strings.Contains(ip, "/") {
		ip = strings.Split(ip, "/")[0]
	}

	return strings.Join(strings.Split(ip, ".")[:3], ".")
}