#!/usr/bin/python
# -*- coding:utf-8 -*-

import time
import random
import socket
import subprocess
from ProxyBuilder import Shadowsocks

def __checkPortAvailable(port, host = '127.0.0.1'):
    s = None
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.settimeout(1)
        s.connect((host, int(port)))
        return False
    except socket.error:
        return True
    finally:
        if s:
            s.close()

def __genTaskFlag(length = 16): # 生成任务代号
    flag = ""
    for i in range(0, length):
        tmp = random.randint(0, 15)
        if tmp >= 10:
            flag += chr(tmp + 87) # a ~ f
        else:
            flag += str(tmp) # 0 ~ 9
    return flag

def __getAvailablePort(rangeStart, rangeEnd): # 获取一个空闲端口
    if rangeStart > rangeEnd:
        return None
    while True:
        port = random.randint(rangeStart, rangeEnd)
        if __checkPortAvailable(port):
            return port
        time.sleep(0.1) # 100ms

def build(proxyInfo, configDir): # 构建代理节点连接
    taskFlag = __genTaskFlag()
    socksPort = __getAvailablePort(1024, 65535)
    if not 'type' in proxyInfo:
        return None
    proxyType = proxyInfo['type'] # 节点类型
    proxyInfo.pop('type')
    configFile = configDir + '/' + taskFlag + '.json' # 配置文件路径
    if (proxyType == 'shadowsocks'): # Shadowsocks节点
        startCommand = Shadowsocks.load(proxyInfo, socksPort, configFile)
    else: # 未知类型
        return None
    process = subprocess.Popen(startCommand, stdout = subprocess.DEVNULL, stderr = subprocess.DEVNULL)
    return { # 返回连接参数
        'flag': taskFlag,
        'port': socksPort,
        'file': configFile,
        'process': process,
        'pid': process.pid,
    }

def check(taskInfo): # 检查客户端是否正常
    process = taskInfo['process']
    if process.poll() != None:
        return False # 死亡
    else:
        return True # 正常

def destroy(taskInfo): # 结束客户端并清理
    process = taskInfo['process']
    if process.poll() == None: # 未死亡
        process.terminate() # SIGTERM
        while process.poll() == None: # 等待退出
            time.sleep(1)
            process.terminate()
    try:
        os.remove(taskInfo.file) # 删除配置文件
    except: pass