import os
import pickle
import string
from cryptography.hazmat.primitives import hashes, serialization
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives.ciphers.aead import AESGCM
from cryptography.hazmat.primitives.kdf.hkdf import HKDF

CURVE = ec.SECP256R1()

def GENERATE_DH():
    return ec.generate_private_key(CURVE)

class MessengerServer:
    def __init__(self, server_signing_key, server_decryption_key):
        self.server_signing_key = server_signing_key
        self.server_decryption_key = server_decryption_key

    def decryptReport(self, ct):
        raise Exception("not implemented!")
        return

    def signCert(self, cert):
        raise Exception("not implemented!")
        return

class MessengerClient:

    def __init__(self, name, server_signing_pk, server_encryption_pk):
        self.name = name
        self.server_signing_pk = server_signing_pk
        self.server_encryption_pk = server_encryption_pk
        self.conns = {}
        self.certs = {}
        self.dh = GENERATE_DH()
        self.certificate = None

    def generateCertificate(self):
        self.certificate = pickle.dumps((self.name, self.dh.public_key().public_bytes(serialization.Encoding.X962,
        serialization.PublicFormat.UncompressedPoint)))
        return self.certificate

    def receiveCertificate(self, certificate, signature):
        raise Exception("not implemented!")
        return

    def sendMessage(self, name, message):
        raise Exception("not implemented!")
        return

    def receiveMessage(self, name, header, ciphertext):
        raise Exception("not implemented!")
        return

    def report(self, name, message):
        raise Exception("not implemented!")
        return