#!/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:
                addr.send(msgs[i])
                # 发送成功则清除对应缓存数据
                del cache[ccid][i] # not msgs[i]
            except:
                # 异常时退出循环
                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:
        # 未报到匹配的在线终端

        #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

        # 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'''

    
    if  data[:5] != b'$TTMS' or len(data) <12:
        # 数据长度不可能小于12，考虑非法接入的可能，主动断开连接
        return -1
    
    
    cmd = data[11+offs]
    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(('localhost',8005), MyServer)
    ip, port = server.server_address
    print ("服务端已建立：",ip, port)
    server.serve_forever()