# server.py
import socket
import shlex
import subprocess

HOST = "0.0.0.0"
PORT = 5055

server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

server_socket.bind((HOST, PORT))
server_socket.listen()

print(f"Server listening on {HOST}:{PORT}")

def send_message(sock, message):
    e_data = message.encode('utf-8')
    #header for the message length
    header = str(len(e_data)).zfill(10).encode('utf-8')
    sock.sendall(header)
    sock.sendall(e_data)

def receive_exact(sock, num_bytes):
    received_data = b""
    while len(received_data) < num_bytes:
        chunk = sock.recv(num_bytes - len(received_data))
        if not chunk:
            raise ConnectionError("connection closed before the full message arrived")
        received_data += chunk
    return received_data

def receive_message(sock):
    header = receive_exact(sock, 10)
    if not header:
        return None
    message_length = int(header.decode('utf-8'))
    received_data = receive_exact(sock, message_length)
    return received_data.decode('utf-8')

while True:
    conn, addr = server_socket.accept()
    print(f"Connected by {addr}")

    command = receive_message(conn)
    if command is None:
        conn.close()
        continue

    command_args = shlex.split(command)

    if not command_args or command_args[0] != "grep":
        response = "Invalid command. Please use the 'grep' command."
        send_message(conn, response)
        conn.close()
        continue

    command_args.insert(1, "-n")

    result = subprocess.run(command_args, cwd="~/fa26_cs425_.group-mp_.team-01/MP1" capture_output=True, text=True)
   
    send_message(conn, result.stdout + result.stderr)

    conn.close()

server_socket.close()