#!/usr/bin/env python3
# coding:utf-8
import socketserver
import subprocess
import pickle


offs = 0  # 偏移量
p = {}
# 保存终端信息，ccid与地址对
# p={ccid=addr,}
# 缓存未能正常发送消息的客户端
pp = {}
# cache={}
from collections import defaultdict

cache = defaultdict(list)


def save_cache(dic):
    """缓存未发送成功的消息
    仅在未发送成功时缓存"""

    # f=open("./cache.txt",mode='w+')
    # f.write(str(dic))
    # f.close
    pickle.dump(dic, open("./cache.txt", "wb"))


def load_cache():
    """程序启动时加载缓存"""
    try:
        # f=open("./cache.txt")
        # c = eval(f.read())
        # f.close()
        c = pickle.load(open("./cache.txt", "rb"))
        return c
    except:
        return None


def update_pairs(addr, ccid, clear=0):
    """更新终端库
    addr:绑定tcp地址
    ccid:终端号
    clear:清空掉线终端"""

    if ccid and not clear:
        # 添加或更新客户端
        p[ccid] = addr
        pp[addr] = ccid
    else:
        del p[ccid]
        del pp[addr]

    # 打印在线终端
    for i in p:
        print(i, "<--->", p[i])
    # for i in pp:
    #     print(i,"-",pp[i])


def get_addr(ccid):
    """获取ccid对应的地址"""

    try:
        # 如果有直接返回
        return p[ccid]
    except Exception:
        # 没有就返回None
        return None


def get_ccid(addr):
    try:
        # 如果有直接返回
        return pp[addr]
    except Exception:
        # 没有就返回None
        return None


"""
+--------+--------------+----------+----------+--------------+------------------------+--------+
|   ff   |     长度     | 地址信息 |          信令           |          内容          | 校验位 |
+--------+--------------+----------+----------+--------------+------------------------+--------+
|        |    2Bytes    |  4Bytes  |   心跳   |     0x01     | 时间戳32bit（单位ms）  | 2Bytes |
+ $TTMS  +--------------+----------+----------+--------------+------------------------+--------+
|        |    2Bytes    |  4Bytes  | 传输数据 |     0xaa     |          载荷          | 2Bytes |
+--------+--------------+----------+----------+--------------+------------------------+--------+
"""


def send(fd, data):
    try:
        fd.send(data)
        return 0
    except:
        return -1


def tt_hh(addr, data):
    """处理心跳"""

    # 更新pairs
    ccid = data[7 + offs : 11 + offs]
    update_pairs(addr, ccid)
    # 组帧再返回

    # 从缓存中匹配数据并重发
    # 仅有新终端上线时才重发
    if ccid in cache:
        msgs = cache[ccid]
        for i in range(len(msgs)):
            try:
                # 按缓存先后顺序发送
                addr.send(msgs[i])
            except:
                # 异常时退出循环，不用再尝试发送后续msgs
                # 退出前清空已发送成功的缓存数据
                # del方法会改变list大小
                while i:
                    cache[ccid].pop(0)
                    i = i - 1
                break

    return 0


def tt_trans(addr, data):
    """发送数据到指定ccid"""

    tccid = data[7 + offs : 11 + offs]
    taddr = get_addr(tccid)
    # 组帧
    msg = bytearray(data[:])
    msg[:5] = b"$TTMX"
    msg[7 + offs : 11 + offs] = get_ccid(addr)

    # 计算校验和
    crc = 0
    for i in msg[:-1]:
        crc = crc ^ i
    msg[-1] = crc

    if not taddr:
        # 未找到匹配的在线终端

        # 更新缓存
        # {tccid1=[msg1,msg2,...],...}
        cache[tccid].append(msg)
        save_cache(cache)

        print("终端未在线或ccid错。")
        return 0
    print("匹配终端：", tccid, "<--->", taddr)

    # 发送
    try:
        taddr.send(msg)
    except Exception:
        # 发送失败
        taddr.close()
        # 更新pairs，清空对应终端
        update_pairs(taddr, tccid, 1)
        # 更新缓存
        # {tccid1=[msg1,msg2,...],...}
        cache[tccid].append(msg)
        save_cache(cache)

        print("发送失败，终端可能已掉线。", taddr)
    return 0


def err_handle(flag, addr):
    """错误处理

    默认打印错误信息

    1-非法连接，关闭连接
    """

    return 0


def tt_decode(addr, data):
    """处理收到的数据
    数据正常返回0
    数据异常返回-1"""

    # 依据帧头和长度初判数据有效性
    if data[:5] != b"$TTMS" or len(data) < 12 or len(data) > 200:
        return -1

    cmd = data[11 + offs]
    # 回退到if-elif，服务器默认版本3.8
    if cmd == 0x01:
        # 处理心跳
        tt_hh(addr, data)
    elif cmd == 0xAA:
        # 处理数据
        tt_trans(addr, data)
    else:
        return -1


class MyServer(socketserver.BaseRequestHandler):
    def handle(self):  # 回调
        print("终端已上线:", self.client_address)
        conn = self.request
        # print(type(conn),conn.fd)

        while True:
            data = conn.recv(200)
            # update_pairs(conn,data[7+offs:11+offs])
            if not data:
                break
            print(
                "接收到新数据", self.client_address, "，长度", len(data), "：\r\n", data.hex(" ")
            )
            # ack_msg = "got from "+ str(ip) + " to " + str(self.client_address) + data
            # conn.send(data[:6])
            if tt_decode(conn, data):
                conn.close()
                print(self.client_address, "疑是非法连接，已切断。")
                break


if __name__ == "__main__":
    # load_cache
    cache = load_cache()

    server = socketserver.ThreadingTCPServer(("", 7222), MyServer)
    ip, port = server.server_address
    print("服务端已建立：", ip, port)
    server.serve_forever()