#!/bin/bash

# 使用 dig 命令查询 DNS 记录并写入 ip.txt
dig cf.youoffer.net A +short > ip.txt

# 创建一个新的文件 ip_use.txt
touch ip_use.txt

# 读取 ip.txt 中的每个 IP 地址进行下载测试
while IFS= read -r ip
do
    echo "Starting download test for $ip"
    # 使用 curl 命令进行下载测试
    start_time=$(date +%s.%N)
    curl -s --resolve speed.cloudflare.com:443:"$ip" https://speed.cloudflare.com/__down?bytes=10000000 -o /dev/null --connect-timeout 5 --max-time 10
    curl_status=$?
    end_time=$(date +%s.%N)
    elapsed_time=$(echo "$end_time - $start_time" | bc)
    
    # 检查 curl 命令的返回状态
    if [ $curl_status -eq 0 ]; then
        # 计算下载速度
        download_speed=$(echo "scale=2; (10000000*8)/(($elapsed_time)*1000000)" | bc)
        
        # 显示下载速度
        echo "$ip has a download speed of $download_speed Mbps"
        
        # 如果下载速度大于等于 50Mbps
        if (( $(echo "$download_speed >= 50" | bc -l) )); then
            # 将大于等于 50Mbps 的 IP 写入 ip_use.txt
            echo "$ip" >> ip_use.txt
        fi
    else
        echo "Download test for $ip failed with status $curl_status"
    fi
done < ip.txt

# 重命名 ip_use.txt 为 final_ips.txt，因为 ip_use.txt 在循环中被touch过，可能包含旧数据
mv ip_use.txt final_ips.txt

echo "Download tests completed. IPs with download speed >= 50Mbps are written to final_ips.txt"