"""

    AUTHOR:

        Khushal P Soonderji

    DATE:

        Thursday, 12th Dec., 2024

    OBJECTIVE:

        To handle all messages from one place.

    REFERENCES:

        N/A

    DOWNLOADS:

        N/A

"""

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# To make sibling directories accessible for imports:
import sys
sys.path.append(".")
sys.path.append("..")

# For Quart:
from quart import current_app

# My async utils:
from utils_v2.string import json
from utils_v2.date_time import date_time
from utils_v2.database.async_mysql_v2 import AsyncMySQL
from utils_v2.database.async_mongo_v2 import AsyncMongo, AsyncMongoStorage

# Base model:
from controllers.base import BaseModel

# Data models:
from models.core.auth_token import CoreAuthTokenModel
from models.core.message import CoreMessageModel
from models.core.user import CoreUserInfoModel

# To work with MongoDB:
from bson import ObjectId
from pymongo import InsertOne, UpdateOne, ReplaceOne

# To work with datatypes:
from typing import Literal, List, Dict, Any

# To make deep-copies:
import copy

# To work with base-64 encoding:
import base64

# To work with date and time:
import datetime

# For asynchronous activities:
import asyncio


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# ***                                                   CLASSES                                                     ***
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class CoreMessageController(BaseModel):

    # ┏┓┓      ┓┏
    # ┃ ┃┏┓┏┏  ┃┃┏┓┏┓┏
    # ┗┛┗┗┻┛┛  ┗┛┗┻┛ ┛

    # For MongoDB:
    MESSAGES_COLLECTION = "_messages"

    # ┏┓┳┓┳┳┳┓      ┏┓
    # ┃ ┣┫┃┃┃┃  ━━  ┃ ┏┓┏┓┏┓╋┏┓
    # ┗┛┛┗┗┛┻┛      ┗┛┛ ┗ ┗┻┗┗

    async def insert(
            self,
            mongo_conn: AsyncMongo,
            message: CoreMessageModel
    ) -> ObjectId:

        """
        Simply insert one message document into the database.
        :param mongo_conn: The instance of the database connector to use for the operation.
        :param message: The message to save into the database.
        :return: The object id of the inserted document.
        """

        # Simply insert the document:
        return await mongo_conn.insert_one(
            collection = self.MESSAGES_COLLECTION,
            document = message,
            raise_exception = True
        )

    async def bulk_write(
            self,
            mongo_conn: AsyncMongo,
            mongo_operations: list
    ) -> int:

        """
        Needed in cases like forcing re-sync of mails where you need to perform actions like bulk replacements of
        existing documents. Not recommended to use. Please use very carefully to ensure document integrity.
        :param mongo_conn: The instance of the database connector to use for the operation.
        :param mongo_operations: The list operations that are supported by MongoDB's Bulk Write system.
        :return: The no. of documents affected.
        """

        return await mongo_conn.bulk_write(
            collection = self.MESSAGES_COLLECTION,
            requests = mongo_operations,
            raise_exception = True
        )

    # ┏┓┳┓┳┳┳┓      ┳┓     •
    # ┃ ┣┫┃┃┃┃  ━━  ┣┫┏┓╋┏┓┓┏┓┓┏┏┓
    # ┗┛┛┗┗┛┻┛      ┛┗┗ ┗┛ ┗┗ ┗┛┗

    async def count_messages(
            self,
            mongo_conn: AsyncMongo,
            token_ids: List[ObjectId | str],
            additional_filter: dict = None
    ) -> int:

        """
        Just counts the no. of messages that match a given set of conditions.
        :param mongo_conn: The instance of the database connector to use for the operation.
        :param token_ids: The token ids of the accounts from which these messages must be fetched.
        :param additional_filter: Any addition filters to use.
        :return: The no. of messages that match the given conditions.
        """

        # Prepare the filter:
        if not isinstance(token_ids, list): token_ids = [token_ids]
        token_ids = [ObjectId(t) for t in token_ids]
        filter_json = {"tokenId": {"$in": token_ids}}
        if additional_filter:
            for k, v in additional_filter.items():
                filter_json[k] = v

        # Get the count of the documents that match the criteria:
        count = await mongo_conn.count(
            collection = self.MESSAGES_COLLECTION,
            filter = filter_json,
            raise_exception = True
        )

        # Done here:
        return count

    async def get_previews(
            self,
            mongo_conn: AsyncMongo,
            token_ids: List[ObjectId | str],
            limit: int = 100,
            skip: int = 0,
            additional_filter: dict = None
    ) -> List[CoreMessageModel] | None:

        """
        Fetches many messages in one call, but leaves out the full payloads.
        :param mongo_conn: The instance of the database connector to use for the operation.
        :param token_ids: The token ids of the accounts from which these messages must be fetched.
        :param limit: The max. no. of messages to retrieve in this call.
        :param skip: The no. of initial messages to skip. Useful for pagination.
        :param additional_filter: Any addition filters to use.
        :return: The list of messages (as the message model). This list can be empty.
        """

        # Prepare the filter:
        if not isinstance(token_ids, list): token_ids = [token_ids]
        token_ids = [ObjectId(t) for t in token_ids]
        filter_json = {"tokenId": {"$in": token_ids}}
        if additional_filter:
            for k, v in additional_filter.items():
                filter_json[k] = v

        # We fetch the messages that are identified by a specific token id,
        # with the specified fetching limits, while enforcing the sorting condition:
        records = await mongo_conn.find_many(
            collection = self.MESSAGES_COLLECTION,
            filter = filter_json,
            limit = limit,
            skip = skip,
            sort = {"ts": -1},
            projection = {
                "_id": True,
                "ts": True,
                "syncTs": True,
                "tokenId": True,
                "serviceType": True,
                "client": True,
                "clientMessageId": True,
                "clientThreadId": True,
                "isSent": True,
                "isBroadcast": True,
                "sentSuccessfully": True,
                "sender": True,
                "chat": True,
                "snippet": True,
                "aiSnippet": True,
                "tags": True
            },
            raise_exception = True
        )

        # Convert the fetched records to instances of the data model and return:
        for record in records: record["message"] = {}
        return [CoreMessageModel(**record) for record in records]

    async def get_messages(
            self,
            mongo_conn: AsyncMongo,
            token_ids: List[ObjectId | str],
            limit: int = 100,
            skip: int = 0,
            additional_filter: dict = None
    ) -> List[CoreMessageModel] | None:

        """
        Fetches many full messages in one call.
        :param mongo_conn: The instance of the database connector to use for the operation.
        :param token_ids: The token ids of the accounts from which these messages must be fetched.
        :param limit: The max. no. of messages to retrieve in this call.
        :param skip: The no. of initial messages to skip. Useful for pagination.
        :param additional_filter: Any addition filters to use.
        :return: The list of messages (as the message model). This list can be empty.
        """

        # Prepare the filter:
        if not isinstance(token_ids, list): token_ids = [token_ids]
        token_ids = [ObjectId(t) for t in token_ids]
        filter_json = {"tokenId": {"$in": token_ids}}
        if additional_filter:
            for k, v in additional_filter.items():
                filter_json[k] = v

        # We fetch the messages that are identified by a specific token id,
        # with the specified fetching limits, while enforcing the sorting condition:
        records = await mongo_conn.find_many(
            collection = self.MESSAGES_COLLECTION,
            filter = filter_json,
            limit = limit,
            skip = skip,
            sort = {"ts": -1},
            raise_exception = True
        )

        # Convert the fetched records to instances of the data model and return:
        return [CoreMessageModel(**record) for record in records]

    async def get_message(
            self,
            mongo_conn: AsyncMongo,
            token_id: ObjectId | str,
            message_id: ObjectId | str,
    ) -> CoreMessageModel | None:

        """
        Gets one message if you know its message id.
        :param mongo_conn: The instance of the database connector to use for the operation.
        :param token_id: The id of the auth-token associated with the message. Needed for security.
        :param message_id: The id of the message that needs to be read.
        :return: The contents of that one message in a structured format.
        """

        # We fetch the whole payload of that one message:
        record = await mongo_conn.find_one(
            collection = self.MESSAGES_COLLECTION,
            filter = {
                "_id": ObjectId(message_id),
                "tokenId": ObjectId(token_id)
            },
            raise_exception = True
        )

        # If no such message was found:
        if record is None: return None

        # If a record was found,
        # we return it as our data model:
        return CoreMessageModel(**record)

    # ┏┓┳┓┳┳┳┓      ┳┳   ┓
    # ┃ ┣┫┃┃┃┃  ━━  ┃┃┏┓┏┫┏┓╋┏┓
    # ┗┛┛┗┗┛┻┛      ┗┛┣┛┗┻┗┻┗┗
    #                 ┛

    # We don't support updating messages themselves,
    # but we will allow updating fields like tags, marking as read or unread, etc.

    async def update_tags(
            self,
            mongo_conn: AsyncMongo,
            token_id: ObjectId | str,
            message_id: ObjectId | str,
            unset_tags: List[str] = None,
            set_tags: List[str] = None
    ) -> bool:

        """
        Updates the tags on one message. The tags to remove are processed first, the ones to add are processed later.
        :param mongo_conn: The instance of the database connector to use for the operation.
        :param token_id: The id of the auth-token associated with the message. Needed for security.
        :param message_id: The id of the message that needs to be read.
        :param unset_tags: The tags to remove from the message.
        :param set_tags: The tags to add to the message.
        :return: True if the update was successful, else False.
        """

        # Update the tags:
        return await mongo_conn.update_one(
            collection = self.MESSAGES_COLLECTION,
            filter = {
                "_id": ObjectId(message_id),
                "tokenId": ObjectId(token_id)
            },
            update = [{
                "$set": {
                    "tags": {
                        "$let": {
                            "vars": {
                                "removed_tags": {
                                    "$setDifference": [
                                        "$tags",
                                        unset_tags
                                    ]
                                }
                            },
                            "in": {
                                "$setUnion": [
                                    "$$removed_tags",
                                    set_tags
                                ]
                            }
                        }
                    }
                }
            }],
            raise_exception = True
        )

    # ┏┓┳┓┳┳┳┓      ┳┓  ┓
    # ┃ ┣┫┃┃┃┃  ━━  ┃┃┏┓┃┏┓╋┏┓
    # ┗┛┛┗┗┛┻┛      ┻┛┗ ┗┗ ┗┗

    # No support whatsoever for deleting messages.


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if __name__ == "__main__":

    pass
