import socket
from common import *
import socket
from AES import AESCipher
import os

HOST = "127.0.0.1"
PORT = TGS_PORT

def process_message(message):
    print(message)
    message = message.split("||")

    if message[0] == "request":
        """
            T_c_tgs = {ID_C + T_R + K_c_tgs}K_tgs

        M3 = [{ID_C + ID_S + T_R + N2}K_c_tgs + T_c_tgs]
        M4 = [{K_c_s + T_A + N2}K_c_tgs + T_c_s]
            T_c_s = {ID_C + T_A + K_c_s}K_s
        """
        body = message[1].split(",")
        K_tgs = C_K_tgs

        M3 = body[0]
        M3 = M3.split(",")
        M3_inner = M3[0]
        T_c_tgs = body[1]
        print('T_c_tgs', type(T_c_tgs), T_c_tgs)

        M3_AES = AESCipher(K_tgs)
        T_c_tgs = M3_AES.decrypt(T_c_tgs)
        T_c_tgs = T_c_tgs.split(",")
        ID_C = T_c_tgs[0]
        T_R = int(T_c_tgs[1])
        K_c_tgs = eval(T_c_tgs[2])

        M3_inner_AES = AESCipher(K_c_tgs)
        M3_inner = M3_inner_AES.decrypt(M3_inner)
        M3_inner = M3_inner.split(",")
        ID_S = M3_inner[1]
        N2 = M3_inner[3]

        # generate M4
        K_c_s = os.urandom(16)
        T_A = 600 if T_R > 600 else T_R
        T_c_s = f"{ID_C},{T_A},{K_c_s}"

        K_s = C_K_s
        T_c_s_AES = AESCipher(K_s)
        T_c_s = T_c_s_AES.encrypt(T_c_s)

        M4_inner = f"{K_c_s},{T_A},{N2}"
        M4_inner_AES = AESCipher(K_c_tgs)
        M4_inner = M4_inner_AES.encrypt(M4_inner)

        M4 = f"{M4_inner},{T_c_s}"
        return M4

def main():
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind((HOST, PORT))
        s.listen()
        while True:
            conn, addr = s.accept()
            with conn:
                print(f"Connected by {addr}")
                all_data = ""
                data = conn.recv(4096)
                all_data += data.decode()

                response = process_message(all_data)

                conn.sendall(response.encode())

if __name__ == "__main__":
    main()