# -*- coding: utf-8 -*-

# Weechat Matrix Protocol Script
# Copyright © 2018 Damir Jelić <poljar@termina.org.uk>
#
# Permission to use, copy, modify, and/or distribute this software for
# any purpose with or without fee is hereby granted, provided that the
# above copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
# RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
# CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

from __future__ import unicode_literals

import socket
import ssl
import textwrap
# pylint: disable=redefined-builtin
from builtins import str
from itertools import chain
# pylint: disable=unused-import
from typing import Any, AnyStr, Deque, Dict, List, Optional, Set, Text, Tuple

import logbook
import OpenSSL.crypto as crypto
from future.utils import bytes_to_native_str as n
from logbook import Logger, StreamHandler
from nio import RemoteProtocolError, RemoteTransportError, TransportType

from matrix import globals as G
from matrix.bar_items import (init_bar_items, matrix_bar_item_buffer_modes,
                              matrix_bar_item_lag, matrix_bar_item_name,
                              matrix_bar_item_plugin)
from matrix.buffer import room_buffer_close_cb, room_buffer_input_cb
# Weechat searches for the registered callbacks in the scope of the main script
# file, import the callbacks here so weechat can find them.
from matrix.commands import (hook_commands, hook_page_up,
                             matrix_command_buf_clear_cb, matrix_command_cb,
                             matrix_command_pgup_cb, matrix_invite_command_cb,
                             matrix_join_command_cb, matrix_kick_command_cb,
                             matrix_me_command_cb, matrix_part_command_cb,
                             matrix_redact_command_cb, matrix_topic_command_cb)
from matrix.completion import (init_completion, matrix_command_completion_cb,
                               matrix_debug_completion_cb,
                               matrix_message_completion_cb,
                               matrix_olm_device_completion_cb,
                               matrix_olm_user_completion_cb,
                               matrix_server_command_completion_cb,
                               matrix_server_completion_cb,
                               matrix_user_completion_cb)
from matrix.config import (MatrixConfig, config_log_category_cb,
                           config_log_level_cb, config_server_buffer_cb,
                           matrix_config_reload_cb)
from matrix.globals import SCRIPT_NAME, SERVERS, W
from matrix.server import (MatrixServer, create_default_server,
                           matrix_config_server_change_cb,
                           matrix_config_server_read_cb,
                           matrix_config_server_write_cb, matrix_timer_cb,
                           send_cb)
from matrix.utf import utf8_decode
from matrix.utils import server_buffer_prnt, server_buffer_set_title

# yapf: disable
WEECHAT_SCRIPT_NAME = SCRIPT_NAME
WEECHAT_SCRIPT_DESCRIPTION = "matrix chat plugin"              # type: str
WEECHAT_SCRIPT_AUTHOR = "Damir Jelić <poljar@termina.org.uk>"  # type: str
WEECHAT_SCRIPT_VERSION = "0.1"                                 # type: str
WEECHAT_SCRIPT_LICENSE = "ISC"                                 # type: str
# yapf: enable


logger = Logger("matrix-cli")


def print_certificate_info(buff, sock, cert):
    cert_pem = ssl.DER_cert_to_PEM_cert(sock.getpeercert(True))

    x509 = crypto.load_certificate(crypto.FILETYPE_PEM, cert_pem)

    public_key = x509.get_pubkey()

    key_type = ("RSA" if public_key.type() == crypto.TYPE_RSA else "DSA")
    key_size = str(public_key.bits())
    sha256_fingerprint = x509.digest(n(b"SHA256"))
    sha1_fingerprint = x509.digest(n(b"SHA1"))
    signature_algorithm = x509.get_signature_algorithm()

    key_info = ("key info: {key_type} key {bits} bits, signed using "
                "{algo}").format(
                    key_type=key_type, bits=key_size, algo=signature_algorithm)

    validity_info = ("        Begins on:  {before}\n"
                     "        Expires on: {after}").format(
                         before=cert["notBefore"], after=cert["notAfter"])

    rdns = chain(*cert["subject"])
    subject = ", ".join(["{}={}".format(name, value) for name, value in rdns])

    rdns = chain(*cert["issuer"])
    issuer = ", ".join(["{}={}".format(name, value) for name, value in rdns])

    subject = "subject: {sub}, serial number {serial}".format(
        sub=subject, serial=cert["serialNumber"])

    issuer = "issuer: {issuer}".format(issuer=issuer)

    fingerprints = ("        SHA1:   {}\n"
                    "        SHA256: {}").format(sha1_fingerprint,
                                                 sha256_fingerprint)

    wrapper = textwrap.TextWrapper(
        initial_indent="    - ", subsequent_indent="        ")

    message = ("{prefix}matrix: received certificate\n"
               " - certificate info:\n"
               "{subject}\n"
               "{issuer}\n"
               "{key_info}\n"
               "    - period of validity:\n{validity_info}\n"
               "    - fingerprints:\n{fingerprints}").format(
                   prefix=W.prefix("network"),
                   subject=wrapper.fill(subject),
                   issuer=wrapper.fill(issuer),
                   key_info=wrapper.fill(key_info),
                   validity_info=validity_info,
                   fingerprints=fingerprints)

    W.prnt(buff, message)


def wrap_socket(server, file_descriptor):
    # type: (MatrixServer, int) -> None
    sock = None  # type: socket.socket

    temp_socket = socket.fromfd(file_descriptor, socket.AF_INET,
                                socket.SOCK_STREAM)

    # For python 2.7 wrap_socket() doesn't work with sockets created from an
    # file descriptor because fromfd() doesn't return a wrapped socket, the bug
    # was fixed for python 3, more info: https://bugs.python.org/issue13942
    # pylint: disable=protected-access,unidiomatic-typecheck
    if type(temp_socket) == socket._socket.socket:
        # pylint: disable=no-member
        sock = socket._socketobject(_sock=temp_socket)
    else:
        sock = temp_socket

    # fromfd() duplicates the file descriptor but doesn't retain it's blocking
    # non-blocking attribute, so mark the socket as non-blocking even though
    # weechat already did that for us
    sock.setblocking(False)

    message = "{prefix}matrix: Doing SSL handshake...".format(
        prefix=W.prefix("network"))
    W.prnt(server.server_buffer, message)

    ssl_socket = server.ssl_context.wrap_socket(
        sock, do_handshake_on_connect=False,
        server_hostname=server.config.address)  # type: ssl.SSLSocket

    server.socket = ssl_socket

    try_ssl_handshake(server)


@utf8_decode
def ssl_fd_cb(server_name, file_descriptor):
    server = SERVERS[server_name]

    if server.ssl_hook:
        W.unhook(server.ssl_hook)
        server.ssl_hook = None

    try_ssl_handshake(server)

    return W.WEECHAT_RC_OK


def try_ssl_handshake(server):
    sock = server.socket

    while True:
        try:
            sock.do_handshake()

            cipher = sock.cipher()
            cipher_message = ("{prefix}matrix: Connected using {tls}, and "
                              "{bit} bit {cipher} cipher suite.").format(
                                  prefix=W.prefix("network"),
                                  tls=cipher[1],
                                  bit=cipher[2],
                                  cipher=cipher[0])
            W.prnt(server.server_buffer, cipher_message)

            cert = sock.getpeercert()
            if cert:
                print_certificate_info(server.server_buffer, sock, cert)

            finalize_connection(server)

            return True

        except ssl.SSLWantReadError:
            hook = W.hook_fd(server.socket.fileno(), 1, 0, 0, "ssl_fd_cb",
                             server.name)
            server.ssl_hook = hook

            return False

        except ssl.SSLWantWriteError:
            hook = W.hook_fd(server.socket.fileno(), 0, 1, 0, "ssl_fd_cb",
                             server.name)
            server.ssl_hook = hook

            return False

        except (ssl.SSLError, socket.error) as error:
            try:
                str_error = error.reason if error.reason else "Unknown error"
            except AttributeError:
                str_error = str(error)

            message = ("{prefix}Error while doing SSL handshake"
                       ": {error}").format(
                           prefix=W.prefix("network"), error=str_error)

            server_buffer_prnt(server, message)

            server_buffer_prnt(
                server, ("{prefix}matrix: disconnecting from server..."
                         ).format(prefix=W.prefix("network")))

            server.disconnect()
            return False


@utf8_decode
def receive_cb(server_name, file_descriptor):
    server = SERVERS[server_name]

    while True:
        try:
            data = server.socket.recv(4096)
        except ssl.SSLWantReadError:
            break
        except socket.error as error:
            errno = "error" + str(error.errno) + " " if error.errno else ""
            str_error = error.strerror if error.strerror else "Unknown error"
            str_error = errno + str_error

            message = ("{prefix}Error while reading from "
                       "socket: {error}").format(
                           prefix=W.prefix("network"), error=str_error)

            server_buffer_prnt(server, message)

            server_buffer_prnt(
                server, ("{prefix}matrix: disconnecting from server..."
                         ).format(prefix=W.prefix("network")))

            server.disconnect()

            return W.WEECHAT_RC_OK

        if not data:
            server_buffer_prnt(
                server,
                "{prefix}matrix: Error while reading from socket".format(
                    prefix=W.prefix("network")))
            server_buffer_prnt(
                server, ("{prefix}matrix: disconnecting from server..."
                         ).format(prefix=W.prefix("network")))

            server.disconnect()
            break

        try:
            server.client.receive(data)
        except (RemoteTransportError, RemoteProtocolError) as e:
            server.error(str(e))
            server.disconnect()
            break

        response = server.client.next_response()

        # Check if we need to send some data back
        data_to_send = server.client.data_to_send()

        if data_to_send:
            server.send(data_to_send)

        if response:
            server.handle_response(response)
            break

    return W.WEECHAT_RC_OK


def finalize_connection(server):
    hook = W.hook_fd(
        server.socket.fileno(),
        1,
        0,
        0,
        "receive_cb",
        server.name
    )

    server.fd_hook = hook
    server.connected = True
    server.connecting = False

    negotiated_protocol = server.socket.selected_alpn_protocol()

    if negotiated_protocol is None:
        negotiated_protocol = server.socket.selected_npn_protocol()

    if negotiated_protocol == "http/1.1":
        server.transport_type = TransportType.HTTP
    elif negotiated_protocol == "h2":
        server.transport_type = TransportType.HTTP2

    data = server.client.connect(server.transport_type)
    server.send(data)

    server.login()


@utf8_decode
def connect_cb(data, status, gnutls_rc, sock, error, ip_address):
    # pylint: disable=too-many-arguments,too-many-branches
    status_value = int(status)  # type: int
    server = SERVERS[data]

    if status_value == W.WEECHAT_HOOK_CONNECT_OK:
        file_descriptor = int(sock)  # type: int
        server.numeric_address = ip_address
        server_buffer_set_title(server)

        wrap_socket(server, file_descriptor)

        return W.WEECHAT_RC_OK

    elif status_value == W.WEECHAT_HOOK_CONNECT_ADDRESS_NOT_FOUND:
        W.prnt(
            server.server_buffer,
            '{address} not found'.format(address=ip_address))

    elif status_value == W.WEECHAT_HOOK_CONNECT_IP_ADDRESS_NOT_FOUND:
        W.prnt(server.server_buffer, 'IP address not found')

    elif status_value == W.WEECHAT_HOOK_CONNECT_CONNECTION_REFUSED:
        W.prnt(server.server_buffer, 'Connection refused')

    elif status_value == W.WEECHAT_HOOK_CONNECT_PROXY_ERROR:
        W.prnt(server.server_buffer,
               'Proxy fails to establish connection to server')

    elif status_value == W.WEECHAT_HOOK_CONNECT_LOCAL_HOSTNAME_ERROR:
        W.prnt(server.server_buffer, 'Unable to set local hostname')

    elif status_value == W.WEECHAT_HOOK_CONNECT_GNUTLS_INIT_ERROR:
        W.prnt(server.server_buffer, 'TLS init error')

    elif status_value == W.WEECHAT_HOOK_CONNECT_GNUTLS_HANDSHAKE_ERROR:
        W.prnt(server.server_buffer, 'TLS Handshake failed')

    elif status_value == W.WEECHAT_HOOK_CONNECT_MEMORY_ERROR:
        W.prnt(server.server_buffer, 'Not enough memory')

    elif status_value == W.WEECHAT_HOOK_CONNECT_TIMEOUT:
        W.prnt(server.server_buffer, 'Timeout')

    elif status_value == W.WEECHAT_HOOK_CONNECT_SOCKET_ERROR:
        W.prnt(server.server_buffer, 'Unable to create socket')
    else:
        W.prnt(
            server.server_buffer,
            'Unexpected error: {status}'.format(status=status_value))

    server.disconnect(reconnect=True)
    return W.WEECHAT_RC_OK


@utf8_decode
def room_close_cb(data, buffer):
    W.prnt("",
           "Buffer '%s' will be closed!" % W.buffer_get_string(buffer, "name"))
    return W.WEECHAT_RC_OK


@utf8_decode
def matrix_unload_cb():
    for server in SERVERS.values():
        server.config.free()

    G.CONFIG.free()

    # for server in SERVERS.values():
    #     server.store_olm()

    return W.WEECHAT_RC_OK


def autoconnect(servers):
    for server in servers.values():
        if server.config.autoconnect:
            server.connect()


def debug_buffer_close_cb(data, buffer):
    G.CONFIG.debug_buffer = ""
    return W.WEECHAT_RC_OK


class WeechatHandler(StreamHandler):
    def __init__(self, level=logbook.NOTSET, format_string=None, filter=None,
                 bubble=False):
        StreamHandler.__init__(
            self,
            object(),
            level,
            format_string,
            None,
            filter,
            bubble
        )

    def write(self, item):
        buf = ""

        if G.CONFIG.network.debug_buffer:
            if not G.CONFIG.debug_buffer:
                G.CONFIG.debug_buffer = W.buffer_new(
                    "Matrix Debug", "", "", "debug_buffer_close_cb", "")

            buf = G.CONFIG.debug_buffer

        W.prnt(buf, item)


if __name__ == "__main__":
    if W.register(WEECHAT_SCRIPT_NAME, WEECHAT_SCRIPT_AUTHOR,
                  WEECHAT_SCRIPT_VERSION, WEECHAT_SCRIPT_LICENSE,
                  WEECHAT_SCRIPT_DESCRIPTION, 'matrix_unload_cb', ''):

        if not W.mkdir_home("matrix", 0o700):
            message = ("{prefix}matrix: Error creating session "
                       "directory").format(prefix=W.prefix("error"))
            W.prnt("", message)

        handler = WeechatHandler()
        handler.format_string = "{record.channel}: {record.message}"
        handler.push_application()

        # TODO if this fails we should abort and unload the script.
        G.CONFIG = MatrixConfig()
        G.CONFIG.read()

        hook_commands()
        init_bar_items()
        init_completion()

        if not SERVERS:
            create_default_server(G.CONFIG)

        autoconnect(SERVERS)