#!/usr/bin/env python3
#coding=utf-8


import socket 
import select 
import serial
import sys
import os
import signal
import time
from timeit import default_timer as timer


class Led:
    def __init__(self, _name=None):
        self.name = _name
        self.path = None
        if self.name :
            self.path = os.path.join("/sys/devices/platform/extgpio/gpios", _name)
            if not os.path.exists(self.path):
                print("led({name}) does not exist".format(name=_name))
                self.path = None
        self.state = 0
    
    def set_value(self, value):
        """
        写入一个值
        """
        if self.path:
            with open(self.path, "w") as fp:
                fp.write(value)
    
    def on(self):
        self.state = 1
        self.set_value("1")
    
    def off(self):
        self.state = 0
        self.set_value("0")

    def revert(self):
        if self.state == 1:
            self.off()
        else:
            self.on()            
class Clients:
    def __init__(self, _sock, _addr):
        self.sock = _sock 
        self.addr = _addr   
        
    def info(self):
        return "%s:%d" % (self.addr[0], self.addr[1])  

def tcp_socket(addr, port):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)    
    try:
        s.bind((addr, port))
    except Exception as e:
        s.close()
        return None 
    s.listen(10)
    return s 

def open_serial(port, rate):
    try:
        s = serial.Serial(port, rate, timeout = 0)        
        return s
    except Exception as e:    
        return None     

running = True
fds = []
clients = []

signal_tx, signal_rx = socket.socketpair()

#查找客户端
def get_client(sock)->Clients:
    for c in clients:
        if c.sock == sock:
            return c
    return None

def close_client(sock):
    #关闭
    sock.close()
    # 从客户端中移除
    fds.remove(sock)            
    # 从监听列表中移除
    for c in clients:
        if c.sock is sock:
            clients.remove(c)


def serial_to_tcp_server(serial_port, serial_rate, local_ip, local_port, led_name):    
    dev = open_serial(serial_port, serial_rate)
    if dev == None:
        print("open serial port failed, please check")
        return 
    
    sock = tcp_socket(local_ip, local_port)
    if sock == None:
        print("open socket failed, please check")
        return 
    
    print("open serial and socket success")
    fds.append(sock)

    fds.append(signal_rx)

    # 打开一个运行灯
    led = Led(led_name)
    # 单位是秒
    led_flash = timer() + 0.1

    loop = True
    while loop: 

        # 处理闪灯
        now = timer()
        if now > led_flash:
            led_flash = now + 0.1
            led.revert()

        # 从串口接收数据 
        if dev.in_waiting > 0:
            data = dev.read(dev.in_waiting)
            #print("serail rx:", data)
            for c in clients:
                c.sock.send(data)

        # 处理信号，连接建立及数据处理       
        r_fds, w_fds, e_fds = select.select(fds, [], [], 0.01)    
        for fd in r_fds:
            if fd is signal_rx:
                data = signal_rx.recv(128)
                #print(data)
                loop = False
            elif fd is sock:
                client_sock, client_addr = sock.accept()
                fds.append(client_sock)
                
                client = Clients(client_sock, client_addr)
                clients.append(client)
                print("connection(%s) setup, total:%d" % (client.info(), len(clients))) 
            else:
                data = fd.recv(1024)
                if not data:                    
                    client = get_client(fd)
                    if client:
                        print("connection(%s) lost" % client.info())
                    close_client(fd)
                else: 
                    #print("tcp rx:", data)
                    dev.write(data)    
    # exit 
    dev.close()
    sock.close()
    led.off()


## 信号处理

def signal_handle(signum:int, frame):
    print("receive signal:", signum)
    ## 发送出去
    signal_tx.send(("%d" % signum).encode())



def print_usage(name):
    usage = \
"""
Usage:
  {program} -h  -- print help
  {program} [-r <baudrate>] [-a <address>] [-p <port>] -l <led> <serial>
    
Parameters:      
  serial   -- serial device name, "COM1" or "/dev/ttyS1"
  baudrate -- baudrate for serial port(115200)
  address  -- binding local IP address(0.0.0.0)
  port     -- tcp server listening port(6390)  
  led      -- specify led indication
"""
    print(usage.format(program=name))    


### 程序入口
def main_entry():
    program = os.path.basename(sys.argv[0])
    serial_port = "/dev/ttyS1"
    serial_rate = 115200
    local_ip = "0.0.0.0"
    local_port = 6390
    dev_led = None

    args = sys.argv
    n = len(args)
    i = 1
    while i < n:
        if args[i] == '-r' and i < n:
            a = args[i + 1]
            if a[0] == '-': break
            try:
                serial_rate = int(args[i + 1])            
            except Exception as e:
                print("***Invalid baudrate rate:", e)
                sys.exit(1)
            i += 1
        elif args[i] == '-a' and i < n:
            a = args[i + 1]
            if a[0] == '-': break
            local_ip = args[i + 1]
            i += 1 
        elif args[i] == '-p' and i < n:
            a = args[i + 1]
            if a[0] == '-': break
            try:
                local_port = int(args[i + 1])            
            except Exception as e:
                print("***Invalid local port:", e)
                sys.exit(1)
            i += 1    
        elif args[i] == '-l' and i < n:
            a = args[i + 1]
            if a[0] == '-': break
            dev_led = args[i + 1]
            i += 1                                           
        elif args[i] == '-h':
            print_usage(program)
            sys.exit(0)
        else:
            if args[i][0] == '-': break                    
            serial_port = args[i]
            i += 1
            break
        i += 1
    
    print("Serial     : {device}@{rate}".format(device = serial_port, rate = serial_rate))
    print("TCP Server : {address}:{port}".format(address = local_ip, port = local_port))

    signal.signal(signal.SIGINT, signal_handle)
    signal.signal(signal.SIGTERM, signal_handle)
    #signal.signal(signal.SIGTSTP, signal_handle)

    serial_to_tcp_server(serial_port, serial_rate, local_ip, local_port, dev_led)

if __name__ == "__main__":
    main_entry()