# -*- coding: future_fstrings -*-
# mautrix-telegram - A Matrix-Telegram puppeting bridge
# Copyright (C) 2018 Tulir Asokan
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
from ruamel.yaml import YAML
from ruamel.yaml.comments import CommentedMap
import random
import string

yaml = YAML()
yaml.indent(4)


class DictWithRecursion:
    def __init__(self, data=None):
        self._data = data or CommentedMap()

    def _recursive_get(self, data, key, default_value):
        if '.' in key:
            key, next_key = key.split('.', 1)
            next_data = data.get(key, CommentedMap())
            return self._recursive_get(next_data, next_key, default_value)
        return data.get(key, default_value)

    def get(self, key, default_value, allow_recursion=True):
        if allow_recursion and '.' in key:
            return self._recursive_get(self._data, key, default_value)
        return self._data.get(key, default_value)

    def __getitem__(self, key):
        return self.get(key, None)

    def __contains__(self, key):
        return self[key] is not None

    def _recursive_set(self, data, key, value):
        if '.' in key:
            key, next_key = key.split('.', 1)
            if key not in data:
                data[key] = CommentedMap()
            next_data = data.get(key, CommentedMap())
            self._recursive_set(next_data, next_key, value)
            return
        data[key] = value

    def set(self, key, value, allow_recursion=True):
        if allow_recursion and '.' in key:
            self._recursive_set(self._data, key, value)
            return
        self._data[key] = value

    def __setitem__(self, key, value):
        self.set(key, value)

    def _recursive_del(self, data, key):
        if '.' in key:
            key, next_key = key.split('.', 1)
            if key not in data:
                return
            next_data = data[key]
            self._recursive_del(next_data, next_key)
            return
        try:
            del data[key]
            del data.ca.items[key]
        except KeyError:
            pass

    def delete(self, key, allow_recursion=True):
        if allow_recursion and '.' in key:
            self._recursive_del(self._data, key)
            return
        try:
            del self._data[key]
            del self._data.ca.items[key]
        except KeyError:
            pass

    def __delitem__(self, key):
        self.delete(key)


class Config(DictWithRecursion):
    def __init__(self, path, registration_path, base_path):
        super().__init__()
        self.path = path
        self.registration_path = registration_path
        self.base_path = base_path
        self._registration = None

    def load(self):
        with open(self.path, 'r') as stream:
            self._data = yaml.load(stream)

    def load_base(self):
        try:
            with open(self.base_path, 'r') as stream:
                return DictWithRecursion(yaml.load(stream))
        except OSError:
            pass
        return None

    def save(self):
        with open(self.path, 'w') as stream:
            yaml.dump(self._data, stream)
        if self._registration and self.registration_path:
            with open(self.registration_path, 'w') as stream:
                yaml.dump(self._registration, stream)

    @staticmethod
    def _new_token():
        return "".join(random.choice(string.ascii_lowercase + string.digits) for _ in range(64))

    def update(self):
        base = self.load_base()
        if not base:
            return

        def copy(from_path, to_path=None):
            if from_path in self:
                base[to_path or from_path] = self[from_path]

        def copy_dict(from_path, to_path=None):
            if from_path in self:
                to_path = to_path or from_path
                base[to_path] = CommentedMap()
                for key, value in self[from_path].items():
                    base[to_path][key] = value

        copy("homeserver.address")
        copy("homeserver.verify_ssl")
        copy("homeserver.domain")

        copy("appservice.protocol")
        copy("appservice.hostname")
        copy("appservice.port")

        copy("appservice.database")

        copy("appservice.public.enabled")
        copy("appservice.public.prefix")
        copy("appservice.public.external")

        copy("appservice.debug")

        copy("appservice.id")
        copy("appservice.bot_username")
        copy("appservice.bot_displayname")

        copy("appservice.as_token")
        copy("appservice.hs_token")

        copy("bridge.username_template")
        copy("bridge.alias_template")
        copy("bridge.displayname_template")

        copy("bridge.displayname_preference")

        copy("bridge.edits_as_replies")
        copy("bridge.highlight_edits")
        copy("bridge.bridge_notices")
        copy("bridge.max_telegram_delete")
        copy("bridge.allow_matrix_login")
        copy("bridge.inline_images")
        copy("bridge.plaintext_highlights")
        copy("bridge.public_portals")
        copy("bridge.native_stickers")

        copy("bridge.command_prefix")

        migrate_permissions = ("bridge.permissions" not in self
                               or "bridge.whitelist" in self
                               or "bridge.admins" in self)
        if migrate_permissions:
            permissions = self["bridge.permissions"] or CommentedMap()
            for entry in self["bridge.whitelist"] or []:
                permissions[entry] = "full"
            for entry in self["bridge.admins"] or []:
                permissions[entry] = "admin"
            base["bridge.permissions"] = permissions
        else:
            copy_dict("bridge.permissions")

        if "bridge.relaybot" not in self:
            copy("bridge.authless_relaybot_portals", "bridge.relaybot.authless_portals")
        else:
            copy("bridge.relaybot.authless_portals")
            copy("bridge.relaybot.whitelist_group_admins")
            copy("bridge.relaybot.whitelist")

        copy("telegram.api_id")
        copy("telegram.api_hash")
        copy("telegram.bot_token")

        self._data = base._data
        self.save()

    def _get_permissions(self, key):
        level = self["bridge.permissions"].get(key, "")
        admin = level == "admin"
        whitelisted = level == "full" or admin
        relaybot = level == "relaybot" or whitelisted
        return relaybot, whitelisted, admin

    def get_permissions(self, mxid):
        permissions = self["bridge.permissions"] or {}
        if mxid in permissions:
            return self._get_permissions(mxid)

        homeserver = mxid[mxid.index(":") + 1:]
        if homeserver in permissions:
            return self._get_permissions(homeserver)

        return self._get_permissions("*")

    def generate_registration(self):
        homeserver = self["homeserver.domain"]

        username_format = self.get("bridge.username_template", "telegram_{userid}") \
            .format(userid=".+")
        alias_format = self.get("bridge.alias_template", "telegram_{groupname}") \
            .format(groupname=".+")

        self.set("appservice.as_token", self._new_token())
        self.set("appservice.hs_token", self._new_token())

        url = (f"{self['appservice.protocol']}://"
               f"{self['appservice.hostname']}:{self['appservice.port']}")
        self._registration = {
            "id": self.get("appservice.id", "telegram"),
            "as_token": self["appservice.as_token"],
            "hs_token": self["appservice.hs_token"],
            "namespaces": {
                "users": [{
                    "exclusive": True,
                    "regex": f"@{username_format}:{homeserver}"
                }],
                "aliases": [{
                    "exclusive": True,
                    "regex": f"#{alias_format}:{homeserver}"
                }]
            },
            "url": url,
            "sender_localpart": self["appservice.bot_username"],
            "rate_limited": False
        }