#!/usr/bin/env python
#
# A library that provides a Python interface to the Telegram Bot API
# Copyright (C) 2015-2020
# Leandro Toledo de Souza <devs@python-telegram-bot.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser 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 Lesser Public License for more details.
#
# You should have received a copy of the GNU Lesser Public License
# along with this program.  If not, see [http://www.gnu.org/licenses/].
"""This module contains the DictPersistence class."""
from copy import deepcopy

from telegram.utils.helpers import decode_user_chat_data_from_json,\
    decode_conversations_from_json, encode_conversations_to_json

try:
    import ujson as json
except ImportError:
    import json
from collections import defaultdict
from telegram.ext import BasePersistence


class DictPersistence(BasePersistence):
    """Using python's dicts and json for making your bot persistent.

    Note:
        This class does *not* implement a :meth:`flush` method, meaning that data managed by
        ``DictPersistence`` is in-memory only and will be lost when the bot shuts down. This is,
        because ``DictPersistence`` is mainly intended as starting point for custom persistence
        classes that need to JSON-serialize the stored data before writing them to file/database.

    Warning:
        :class:`DictPersistence` will try to replace :class:`telegram.Bot` instances by
        :attr:`REPLACED_BOT` and insert the bot set with
        :meth:`telegram.ext.BasePersistence.set_bot` upon loading of the data. This is to ensure
        that changes to the bot apply to the saved objects, too. If you change the bots token, this
        may lead to e.g. ``Chat not found`` errors. For the limitations on replacing bots see
        :meth:`telegram.ext.BasePersistence.replace_bot` and
        :meth:`telegram.ext.BasePersistence.insert_bot`.

    Attributes:
        store_user_data (:obj:`bool`): Whether user_data should be saved by this
            persistence class.
        store_chat_data (:obj:`bool`): Whether chat_data should be saved by this
            persistence class.
        store_bot_data (:obj:`bool`): Whether bot_data should be saved by this
            persistence class.

    Args:
        store_user_data (:obj:`bool`, optional): Whether user_data should be saved by this
            persistence class. Default is :obj:`True`.
        store_chat_data (:obj:`bool`, optional): Whether user_data should be saved by this
            persistence class. Default is :obj:`True`.
        store_bot_data (:obj:`bool`, optional): Whether bot_data should be saved by this
            persistence class. Default is :obj:`True` .
        user_data_json (:obj:`str`, optional): Json string that will be used to reconstruct
            user_data on creating this persistence. Default is ``""``.
        chat_data_json (:obj:`str`, optional): Json string that will be used to reconstruct
            chat_data on creating this persistence. Default is ``""``.
        bot_data_json (:obj:`str`, optional): Json string that will be used to reconstruct
            bot_data on creating this persistence. Default is ``""``.
        conversations_json (:obj:`str`, optional): Json string that will be used to reconstruct
            conversation on creating this persistence. Default is ``""``.
    """

    def __init__(self,
                 store_user_data=True,
                 store_chat_data=True,
                 store_bot_data=True,
                 user_data_json='',
                 chat_data_json='',
                 bot_data_json='',
                 conversations_json=''):
        super().__init__(store_user_data=store_user_data,
                         store_chat_data=store_chat_data,
                         store_bot_data=store_bot_data)
        self._user_data = None
        self._chat_data = None
        self._bot_data = None
        self._conversations = None
        self._user_data_json = None
        self._chat_data_json = None
        self._bot_data_json = None
        self._conversations_json = None
        if user_data_json:
            try:
                self._user_data = decode_user_chat_data_from_json(user_data_json)
                self._user_data_json = user_data_json
            except (ValueError, AttributeError):
                raise TypeError("Unable to deserialize user_data_json. Not valid JSON")
        if chat_data_json:
            try:
                self._chat_data = decode_user_chat_data_from_json(chat_data_json)
                self._chat_data_json = chat_data_json
            except (ValueError, AttributeError):
                raise TypeError("Unable to deserialize chat_data_json. Not valid JSON")
        if bot_data_json:
            try:
                self._bot_data = json.loads(bot_data_json)
                self._bot_data_json = bot_data_json
            except (ValueError, AttributeError):
                raise TypeError("Unable to deserialize bot_data_json. Not valid JSON")
            if not isinstance(self._bot_data, dict):
                raise TypeError("bot_data_json must be serialized dict")

        if conversations_json:
            try:
                self._conversations = decode_conversations_from_json(conversations_json)
                self._conversations_json = conversations_json
            except (ValueError, AttributeError):
                raise TypeError("Unable to deserialize conversations_json. Not valid JSON")

    @property
    def user_data(self):
        """:obj:`dict`: The user_data as a dict."""
        return self._user_data

    @property
    def user_data_json(self):
        """:obj:`str`: The user_data serialized as a JSON-string."""
        if self._user_data_json:
            return self._user_data_json
        else:
            return json.dumps(self.user_data)

    @property
    def chat_data(self):
        """:obj:`dict`: The chat_data as a dict."""
        return self._chat_data

    @property
    def chat_data_json(self):
        """:obj:`str`: The chat_data serialized as a JSON-string."""
        if self._chat_data_json:
            return self._chat_data_json
        else:
            return json.dumps(self.chat_data)

    @property
    def bot_data(self):
        """:obj:`dict`: The bot_data as a dict."""
        return self._bot_data

    @property
    def bot_data_json(self):
        """:obj:`str`: The bot_data serialized as a JSON-string."""
        if self._bot_data_json:
            return self._bot_data_json
        else:
            return json.dumps(self.bot_data)

    @property
    def conversations(self):
        """:obj:`dict`: The conversations as a dict."""
        return self._conversations

    @property
    def conversations_json(self):
        """:obj:`str`: The conversations serialized as a JSON-string."""
        if self._conversations_json:
            return self._conversations_json
        else:
            return encode_conversations_to_json(self.conversations)

    def get_user_data(self):
        """Returns the user_data created from the ``user_data_json`` or an empty
        :obj:`defaultdict`.

        Returns:
            :obj:`defaultdict`: The restored user data.
        """
        if self.user_data:
            pass
        else:
            self._user_data = defaultdict(dict)
        return deepcopy(self.user_data)

    def get_chat_data(self):
        """Returns the chat_data created from the ``chat_data_json`` or an empty
        :obj:`defaultdict`.

        Returns:
            :obj:`defaultdict`: The restored chat data.
        """
        if self.chat_data:
            pass
        else:
            self._chat_data = defaultdict(dict)
        return deepcopy(self.chat_data)

    def get_bot_data(self):
        """Returns the bot_data created from the ``bot_data_json`` or an empty :obj:`dict`.

        Returns:
            :obj:`dict`: The restored bot data.
        """
        if self.bot_data:
            pass
        else:
            self._bot_data = {}
        return deepcopy(self.bot_data)

    def get_conversations(self, name):
        """Returns the conversations created from the ``conversations_json`` or an empty
        :obj:`dict`.

        Returns:
            :obj:`dict`: The restored conversations data.
        """
        if self.conversations:
            pass
        else:
            self._conversations = {}
        return self.conversations.get(name, {}).copy()

    def update_conversation(self, name, key, new_state):
        """Will update the conversations for the given handler.

        Args:
            name (:obj:`str`): The handler's name.
            key (:obj:`tuple`): The key the state is changed for.
            new_state (:obj:`tuple` | :obj:`any`): The new state for the given key.
        """
        if self._conversations.setdefault(name, {}).get(key) == new_state:
            return
        self._conversations[name][key] = new_state
        self._conversations_json = None

    def update_user_data(self, user_id, data):
        """Will update the user_data (if changed).

        Args:
            user_id (:obj:`int`): The user the data might have been changed for.
            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.user_data` [user_id].
        """
        if self._user_data is None:
            self._user_data = defaultdict(dict)
        if self._user_data.get(user_id) == data:
            return
        self._user_data[user_id] = data
        self._user_data_json = None

    def update_chat_data(self, chat_id, data):
        """Will update the chat_data (if changed).

        Args:
            chat_id (:obj:`int`): The chat the data might have been changed for.
            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.chat_data` [chat_id].
        """
        if self._chat_data is None:
            self._chat_data = defaultdict(dict)
        if self._chat_data.get(chat_id) == data:
            return
        self._chat_data[chat_id] = data
        self._chat_data_json = None

    def update_bot_data(self, data):
        """Will update the bot_data (if changed).

        Args:
            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.bot_data`.
        """
        if self._bot_data == data:
            return
        self._bot_data = data.copy()
        self._bot_data_json = None