package main

import (
	"bufio"
	"fmt"
	"net"
	"net/http"
	"strings"
	"time"
)

const proxyListURL = "https://gh-proxy.org/https://github.com/hookzof/socks5_list/blob/master/proxy.txt"

func main() {
	// 1. 拉取代理列表
	resp, err := http.Get(proxyListURL)
	if err != nil {
		panic(fmt.Errorf("获取代理列表失败: %w", err))
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		panic(fmt.Errorf("获取代理列表失败，HTTP 状态码: %d", resp.StatusCode))
	}

	scanner := bufio.NewScanner(resp.Body)
	var proxies []string
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		// 每一行形如 "ip:port"
		proxies = append(proxies, line)
	}
	if err := scanner.Err(); err != nil {
		panic(fmt.Errorf("读取列表内容失败: %w", err))
	}

	if len(proxies) == 0 {
		fmt.Println("代理列表为空")
		return
	}

	fmt.Printf("共读取到 %d 个代理，开始测试...\n", len(proxies))

	// 2. 依次测试每个代理的 TCP 连接耗时
	var (
		bestProxy   string
		bestLatency time.Duration
	)

	for _, addr := range proxies {
		latency, err := testProxyTCP(addr, 3*time.Second)
		if err != nil {
			fmt.Printf("[失败] %s: %v\n", addr, err)
			continue
		}
		fmt.Printf("[成功] %s 延迟: %v\n", addr, latency)

		if bestProxy == "" || latency < bestLatency {
			bestProxy = addr
			bestLatency = latency
		}
	}

	// 3. 输出结果
	if bestProxy == "" {
		fmt.Println("没有找到可用的代理服务器")
		return
	}

	fmt.Println("====================================")
	fmt.Printf("最快代理服务器: %s，延迟: %v\n", bestProxy, bestLatency)

	// 4. 输出一个可在 Telegram 中自动配置的 tg 链接（基于 SOCKS5）
	parts := strings.Split(bestProxy, ":")
	if len(parts) == 2 {
		server := parts[0]
		port := parts[1]
		tgLink := fmt.Sprintf("tg://socks?server=%s&port=%s", server, port)
		fmt.Println("Telegram 一键配置链接:")
		fmt.Println(tgLink)
	} else {
		fmt.Println("无法生成 Telegram 链接，代理地址不是 ip:port 格式:", bestProxy)
	}
}

// testProxyTCP 尝试建立到代理服务器的 TCP 连接，并返回耗时
func testProxyTCP(addr string, timeout time.Duration) (time.Duration, error) {
	start := time.Now()
	conn, err := net.DialTimeout("tcp", addr, timeout)
	if err != nil {
		return 0, err
	}
	defer conn.Close()
	return time.Since(start), nil
}