# Copyright (C) 2018 Philipp Hörist <philipp AT hoerist.com>
#
# This file is part of Gajim.
#
# Gajim is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published
# by the Free Software Foundation; version 3 only.
#
# Gajim is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Gajim. If not, see <http://www.gnu.org/licenses/>.

# XEP-0373: OpenPGP for XMPP

import logging
import os
from pathlib import Path

from gi.repository import Gtk
from gi.repository import Gdk

from gajim.plugins import GajimPlugin
from gajim.common import app
from gajim.common import ged
from gajim.common import configpaths
from gajim.common import helpers
from gajim.common.const import CSSPriority
from gajim.gtk.dialogs import ErrorDialog

from openpgp.modules.util import NS_NOTIFY
from openpgp.modules import pgp_keylist
try:
    from openpgp.modules import openpgp
except ImportError as e:
    ERROR_MSG = str(e)
else:
    ERROR_MSG = None

log = logging.getLogger('gajim.plugin_system.openpgp')


#TODO: we cant encrypt "thread" right now, because its needed for Gajim to find ChatControls.

class OpenPGPPlugin(GajimPlugin):
    def init(self):
        if ERROR_MSG:
            self.activatable = False
            self.available_text = ERROR_MSG
            self.config_dialog = None
            return

        self.events_handlers = {
            'signed-in': (ged.PRECORE, self.signed_in),
            }

        self.modules = [pgp_keylist,
                        openpgp]

        self.encryption_name = 'OpenPGP'
        self.config_dialog = None
        self.gui_extension_points = {
            'encrypt' + self.encryption_name: (self._encrypt_message, None),
            'decrypt': (self._decrypt_message, None),
            'send_message' + self.encryption_name: (
                self._before_sendmessage, None),
            'encryption_dialog' + self.encryption_name: (
                self.on_encryption_button_clicked, None),
            'encryption_state' + self.encryption_name: (
                self.encryption_state, None),
            'update_caps': (self._update_caps, None),
            }

        self.connections = {}

        self.plugin = self
        self.announced = []
        self.own_key = None
        self.pgp_instances = {}
        self._create_paths()
        self._load_css()

    def _load_css(self):
        path = Path(__file__).parent / 'gtk' / 'style.css'
        try:
            with open(path, "r") as f:
                css = f.read()
        except Exception as exc:
            log.error('Error loading css: %s', exc)
            return

        try:
            provider = Gtk.CssProvider()
            provider.load_from_data(bytes(css.encode('utf-8')))
            Gtk.StyleContext.add_provider_for_screen(Gdk.Screen.get_default(),
                                                     provider,
                                                     CSSPriority.DEFAULT_THEME)
        except Exception:
            log.exception('Error loading application css')

    def _create_paths(self):
        keyring_path = os.path.join(configpaths.get('MY_DATA'), 'openpgp')
        if not os.path.exists(keyring_path):
            os.makedirs(keyring_path)

    def signed_in(self, event):
        account = event.conn.name
        con = app.connections[account]
        if con.get_module('OpenPGP').secret_key_available:
            log.info('%s => Publish keylist and public key after sign in',
                     account)
            con.get_module('OpenPGP').query_key_list()
            con.get_module('OpenPGP').publish_key()

    def activate(self):
        for account in app.connections:
            if app.caps_hash[account] != '':
                # Gajim has already a caps hash calculated, update it
                helpers.update_optional_features(account)

            con = app.connections[account]
            if app.account_is_connected(account):
                if con.get_module('OpenPGP').secret_key_available:
                    log.info('%s => Publish keylist and public key '
                             'after plugin activation', account)
                    con.get_module('OpenPGP').query_key_list()
                    con.get_module('OpenPGP').publish_key()

    def deactivate(self):
        pass

    @staticmethod
    def _update_caps(account):
        if NS_NOTIFY not in app.gajim_optional_features[account]:
            app.gajim_optional_features[account].append(NS_NOTIFY)

    def activate_encryption(self, chat_control):
        account = chat_control.account
        jid = chat_control.contact.jid
        con = app.connections[account]
        if con.get_module('OpenPGP').secret_key_available:
            keys = app.connections[account].get_module('OpenPGP').get_keys(
                jid, only_trusted=False)
            if not keys:
                con.get_module('OpenPGP').query_key_list(jid)
                ErrorDialog(
                    _('No OpenPGP key'),
                    _('We didnt receive a OpenPGP key from this contact.'))
                return
            return True
        else:
            from openpgp.gtk.wizard import KeyWizard
            KeyWizard(self, account, chat_control)

    def encryption_state(self, chat_control, state):
        state['authenticated'] = True
        state['visible'] = True

    def on_encryption_button_clicked(self, chat_control):
        account = chat_control.account
        jid = chat_control.contact.jid
        transient = chat_control.parent_win.window

        from openpgp.gtk.key import KeyDialog
        KeyDialog(account, jid, transient)

    def _before_sendmessage(self, chat_control):
        account = chat_control.account
        jid = chat_control.contact.jid
        con = app.connections[account]

        if not con.get_module('OpenPGP').secret_key_available:
            from openpgp.gtk.wizard import KeyWizard
            KeyWizard(self, account, chat_control)
            return

        keys = con.get_module('OpenPGP').get_keys(jid)
        if not keys:
            ErrorDialog(
                _('Not Trusted'),
                _('There was no trusted and active key found'))
            chat_control.sendmessage = False

    def _encrypt_message(self, con, obj, callback):
        if not con.get_module('OpenPGP').secret_key_available:
            return
        con.get_module('OpenPGP').encrypt_message(obj, callback)

    def _decrypt_message(self, con, obj, callback):
        if not con.get_module('OpenPGP').secret_key_available:
            return
        con.get_module('OpenPGP').decrypt_message(obj, callback)