import os
import socket
import random

#这里把端口单独领出来是因为上学期做实验的时候很容易出现端口占用的情况，放这容易改
PORT = 8081
MAXSIZE = 1024
#这里是设置了一个结束符，当client输入eixt的时候就结束通信
EXIT_SYMBOL = "exit"
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#这里前面是地址，后面是端口，为了方便测试就把地址设为本机，127.0.0.0，0.0.0.0，localhost都是可以的
server_socket.bind(('0.0.0.0', PORT))
server_socket.listen(1)
print(f"Server is listening on port {PORT}...")

client_socket, client_address = server_socket.accept()
print("Client connected!")

try:
    with open('file1.txt', 'r',encoding='utf-8') as file1, open('file2.txt', 'w',encoding='utf-8') as file2:
        while True:
            data = client_socket.recv(MAXSIZE).decode('utf-8')
            if not data:
                break
            if data.startswith(EXIT_SYMBOL):
                print("Received exit command from client.")
                break
            print(data)
            file2.write(data)
            file1.seek(0)
            file1_content = file1.read(MAXSIZE - 1)
            data_len = random.randint(1, len(file1_content))
            client_socket.sendall(file1_content[:data_len].encode())
except Exception as e:
    print(f"An error occurred: {e}")
finally:
    client_socket.close()
    server_socket.close()
    print("Server closed.")