"""

    AUTHOR:

        Khushal P Soonderji

    DATE:

        Thursday, 12th Dec., 2024

    OBJECTIVE:

        To define all file-management activities in 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("..")

# System-level:
import io
# My async utils:
from utils_v2.string import json
from utils_v2.date_time import date_time
from utils_v2.system import files
from utils_v2.security.hash import Hasher
from utils_v2.database.async_mysql_v2 import AsyncMySQL
from utils_v2.database.async_mongo_v2 import AsyncMongo, AsyncMongoStorage

# Base model:
from models.behaviour.base import BaseModel

# Data models:
from models.data.core.user import CoreUserInfoModel
from models.data.core.file import CoreFileInfoModel, CoreFileAccessResponseModel

# To work with MongoDB:
from bson import ObjectId

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

# To make deep copies:
import copy

# For debugging:
from icecream import IceCreamDebugger


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# --- Nothing Yet


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# ***                                                  FUNCTIONS                                                    ***
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# ***                                                   CLASSES                                                     ***
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class FileManagementModel:

    def __init__(
            self,
            debug = True,
            debug_prefix = "File Objs. | ",
    ):

        # Debugging:
        self._printer = IceCreamDebugger(prefix = debug_prefix, includeContext = True)
        if not debug: self._printer.disable()

    def enable_debug(self):
        self._printer.enable()

    def disable_debug(self):
        self._printer.disable()

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

    async def exists(
            self,
            mongo_conn: AsyncMongoStorage,
            file_id: ObjectId | str
    ) -> CoreFileAccessResponseModel:

        """
        To check whether, or not, a particular file's record exists in the database.
        :param mongo_conn: The instance of the database connection to perform this action.
        :param file_id: The id of the file to check.
        :return: A structured response where the existence of the file is noted in the 'result' field.
        """

        # Create a response:
        response = CoreFileAccessResponseModel()

        try:

            # Run the query:
            record = await mongo_conn.find_one_file(
                filter = {"_id": ObjectId(file_id)},
                projection = {"_id": True, "user": True},
                raise_exception = True
            )

            # Note down the result:
            if record:
                response.data = True
                response.success = True
                response.message = "ok"

        except Exception as exception:
            self._printer(exception)
            response.exception = exception
            response.message = str(exception)
            response.success = False
            response.data = None

        # Done here:
        return response

    async def info(
            self,
            mongo_conn: AsyncMongoStorage,
            file_id: ObjectId | str
    ) -> CoreFileAccessResponseModel:

        """
        To get the information about this file.
        :param mongo_conn: The instance of the database connection to perform this action.
        :param file_id: The id of the file to check.
        :return: A structured response where the info of the file is noted in the 'result' field.
        """

        # Create a response:
        response = CoreFileAccessResponseModel()

        try:

            # Run the query:
            record = await mongo_conn.find_one_file(
                filter = {"_id": ObjectId(file_id)},
                raise_exception = True
            )

            # Note down the result:
            response.success = True
            if record:
                response.data = CoreFileInfoModel(**record["metadata"])
                response.message = "ok"
            else:
                response.message = "no such file object"

        # If something goes wrong:
        except Exception as exception:
            self._printer(exception)
            response.exception = exception
            response.message = str(exception)
            response.success = False
            response.data = None

        # Done here:
        return response

    async def is_private(
            self,
            mongo_conn: AsyncMongoStorage,
            file_id: ObjectId | str
    ) -> bool | None:

        """
        To check whether, or not, a particular file is publicly readable.
        :param mongo_conn: The instance of the database connection to perform this action.
        :param file_id: The id of the file to check.
        :return: True if private, else False. None if it doesn't exist at all.
        """

        # Create a response:
        response = CoreFileAccessResponseModel()

        try:

            # Run the query:
            record = await mongo_conn.find_one_file(
                filter = {"_id": ObjectId(file_id)},
                projection = {"_id": False, "isPrivate": True},
                raise_exception = True
            )

            # Note down the result:
            if record:
                response.data = record["metadata"]["isPrivate"]
                response.success = True
                response.message = "ok"

        # If something goes wrong:
        except Exception as exception:
            self._printer(exception)
            response.exception = exception
            response.message = str(exception)
            response.success = False
            response.data = None

        # Done here:
        return response

    # ┓ •  •
    # ┃ ┓┏╋┓┏┓┏┓
    # ┗┛┗┛┗┗┛┗┗┫
    #          ┛

    pass

    # ┳┓     ┓•
    # ┣┫┏┓┏┓┏┫┓┏┓┏┓
    # ┛┗┗ ┗┻┗┻┗┛┗┗┫
    #             ┛

    async def download_file(
            self,
            mongo_conn: AsyncMongoStorage,
            file_id: ObjectId | str
    ) -> CoreFileAccessResponseModel:

        """
        To quickly download small files. Do not use this for larger files because the file will be held in RAM first
        and any large file will end up filling RAM fast. It's okay for smaller files that won't block up the memory.
        :param mongo_conn: The instance of the database connection to perform this action.
        :param file_id: The id of the file to fetch.
        :return: The file in a BytesIO buffer in the 'data' field of the structured response.
        """

        # Create a response:
        response = CoreFileAccessResponseModel()

        try:

            # Get the file from the database:
            buffer = io.BytesIO()
            response.success = await mongo_conn.easy_download(
                destination = buffer,
                file_id = ObjectId(file_id),
                raise_exception = True
            )
            buffer.seek(0)

            # Note down the results:
            response.message = (
                "file fetched successfully" if response.success
                else "file fetching failed"
            )
            response.data = buffer if response.success else None

        # If something goes wrong:
        except Exception as exception:
            self._printer(exception)
            response.exception = exception
            response.message = str(exception)
            response.success = False
            response.data = None

        # Done here:
        return response

    @staticmethod
    async def get_file_download_stream(
            mongo_conn: AsyncMongoStorage,
            file_id: ObjectId
    ) -> Any:

        """
        To download any file as a stream. Better than the simple 'download' method because it doesn't block RAM. Once
        the stream is created you can read from it, and terminate it like this:
        READ: await stream.read(chunk_size)
        CLOSE (without awaiting): stream.close()
        :param mongo_conn: The instance of the database connection to perform this action.
        :param file_id: The id of the file whose stream you would like to fetch.
        :return: Returns the stream object that will allow more efficient downloads of files on the user's end.
        """

        return await mongo_conn.get_download_stream(file_id = file_id)

    # ┓ ┏  • •
    # ┃┃┃┏┓┓╋┓┏┓┏┓
    # ┗┻┛┛ ┗┗┗┛┗┗┫
    #            ┛

    async def upload_file(
            self,
            mongo_conn: AsyncMongoStorage,
            file_info: CoreFileInfoModel,
            file_data: io.BytesIO | str,
            chunk_size: int = None
    ):

        # Create a response:
        response = CoreFileAccessResponseModel()

        try:

            # Read the file's data into a BytesIO object:
            if isinstance(file_data, str):
                file_data = io.BytesIO(files.read_file(file_data, mode = "rb"))
                file_data.seek(0)

            # Hash the file's data:
            hasher = Hasher()
            hasher.update(file_data.getvalue())
            file_info.hash = hasher.hexdigest()

            # Save the file to the database:
            file_data.seek(0)
            response.success = await mongo_conn.easy_upload(
                source = file_data,
                file_name = file_info.filename,
                file_metadata = file_info.model_dump(),
                file_id = file_info.fileId,
                chunk_size = chunk_size,
                raise_exception = True
            )

            # Note down the results:
            response.message = (
                "file saved successfully" if response.success
                else "file saving failed"
            )
            response.data = True if response.success else False

        # If something goes wrong:
        except Exception as exception:
            self._printer(exception)
            response.exception = exception
            response.message = str(exception)
            response.success = False
            response.data = None

        # Done here:
        return response

    async def upload_from_stream(self): pass

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

    async def delete_file(self): pass

    # ┏┓       •  •
    # ┃┃┏┓┏┓┏┳┓┓┏┏┓┏┓┏┓┏
    # ┣┛┗ ┛ ┛┗┗┗┛┛┗┗┛┛┗┛

    async def make_public(self): pass

    async def make_private(self): pass


#   *****************************************************************************************************************
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if __name__ == "__main__":

    import asyncio
    import time

    async def main():

        files_mongo = AsyncMongoStorage(
            connection_string = r"mongodb://del.ditscentre.in:27017,wtt.ditscentre.in:27017,mum.arh.001.ditscentre.in:27017/admin?tls=true&tlsCAFile=%2Fetc%2Fssl%2Fcerts%2Fmongo_data_ca.pem&tlsCertificateKeyFile=%2Fetc%2Fssl%2Fcerts%2Fmongo_data_cert.pem&replicaSet=dits_mongod_rep&readPreference=primary&authMechanism=MONGODB-X509&authSource=%24external",
            database_name = "converseStore",
            max_connections = 10,
            debug = True
        )
        await files_mongo.connect()
        my_files = FileManagementModel()

        user_bhopli = CoreUserInfoModel(
            fullName = "Bhopli Narangi",
            userId = 1,
            entityId = 2,
            billingAccountId = 3,
            departmentId = 4,
            branchId = 5,
            industry = "technology"
        )

        file_info = await my_files.info(
            mongo_conn = files_mongo,
            file_id = "67598d48c1bf89b25695f20b"
        )
        print("FILE INFO:", json.to_string(file_info.model_dump(), default = str))


    asyncio.run(main())