# Pyrogram - Telegram MTProto API Client Library for Python
# Copyright (C) 2017-2019 Dan Tès <https://github.com/delivrance>
#
# This file is part of Pyrogram.
#
# Pyrogram is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Pyrogram 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 General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Pyrogram.  If not, see <http://www.gnu.org/licenses/>.

import asyncio
import binascii
import os
import struct
import time
from datetime import datetime
from threading import Event
from typing import Union

import pyrogram
from pyrogram.client.ext import BaseClient, FileData, utils
from pyrogram.errors import FileIdInvalid

DEFAULT_DOWNLOAD_DIR = "downloads/"


class DownloadMedia(BaseClient):
    async def download_media(
        self,
        message: Union["pyrogram.Message", str],
        file_name: str = DEFAULT_DOWNLOAD_DIR,
        block: bool = True,
        progress: callable = None,
        progress_args: tuple = ()
    ) -> Union[str, None]:
        """Download the media from a message.

        Parameters:
            message (:obj:`Message` | ``str``):
                Pass a Message containing the media, the media itself (message.audio, message.video, ...) or
                the file id as string.

            file_name (``str``, *optional*):
                A custom *file_name* to be used instead of the one provided by Telegram.
                By default, all files are downloaded in the *downloads* folder in your working directory.
                You can also specify a path for downloading files in a custom location: paths that end with "/"
                are considered directories. All non-existent folders will be created automatically.

            block (``bool``, *optional*):
                Blocks the code execution until the file has been downloaded.
                Defaults to True.

            progress (``callable``, *optional*):
                Pass a callback function to view the file transmission progress.
                The function must take *(current, total)* as positional arguments (look at Other Parameters below for a
                detailed description) and will be called back each time a new file chunk has been successfully
                transmitted.

            progress_args (``tuple``, *optional*):
                Extra custom arguments for the progress callback function.
                You can pass anything you need to be available in the progress callback scope; for example, a Message
                object or a Client instance in order to edit the message with the updated progress status.

        Other Parameters:
            current (``int``):
                The amount of bytes transmitted so far.

            total (``int``):
                The total size of the file.

            *args (``tuple``, *optional*):
                Extra custom arguments as defined in the *progress_args* parameter.
                You can either keep *\*args* or add every single extra argument in your function signature.

        Returns:
            ``str`` | ``None``: On success, the absolute path of the downloaded file is returned, otherwise, in case
            the download failed or was deliberately stopped with :meth:`~Client.stop_transmission`, None is returned.

        Raises:
            ValueError: if the message doesn't contain any downloadable media

        Example:
            .. code-block:: python

                # Download from Message
                app.download_media(message)

                # Download from file id
                app.download_media("CAADBAADyg4AAvLQYAEYD4F7vcZ43AI")
        """
        error_message = "This message doesn't contain any downloadable media"
        available_media = ("audio", "document", "photo", "sticker", "animation", "video", "voice", "video_note")

        media_file_name = None
        file_size = None
        mime_type = None
        date = None

        if isinstance(message, pyrogram.Message):
            for kind in available_media:
                media = getattr(message, kind, None)

                if media is not None:
                    break
            else:
                raise ValueError(error_message)
        else:
            media = message

        if isinstance(media, str):
            file_id_str = media
        else:
            file_id_str = media.file_id
            media_file_name = getattr(media, "file_name", "")
            file_size = getattr(media, "file_size", None)
            mime_type = getattr(media, "mime_type", None)
            date = getattr(media, "date", None)

        data = FileData(
            file_name=media_file_name,
            file_size=file_size,
            mime_type=mime_type,
            date=date
        )

        def get_existing_attributes() -> dict:
            return dict(filter(lambda x: x[1] is not None, data.__dict__.items()))

        try:
            decoded = utils.decode(file_id_str)
            media_type = decoded[0]

            if media_type == 1:
                unpacked = struct.unpack("<iiqqqiiiqi", decoded)
                dc_id, photo_id, _, volume_id, size_type, peer_id, _, peer_access_hash, local_id = unpacked[1:]

                data = FileData(
                    **get_existing_attributes(),
                    media_type=media_type,
                    dc_id=dc_id,
                    peer_id=peer_id,
                    peer_access_hash=peer_access_hash,
                    volume_id=volume_id,
                    local_id=local_id,
                    is_big=size_type == 3
                )
            elif media_type in (0, 2, 14):
                unpacked = struct.unpack("<iiqqqiiii", decoded)
                dc_id, document_id, access_hash, volume_id, _, _, thumb_size, local_id = unpacked[1:]

                data = FileData(
                    **get_existing_attributes(),
                    media_type=media_type,
                    dc_id=dc_id,
                    document_id=document_id,
                    access_hash=access_hash,
                    thumb_size=chr(thumb_size)
                )
            elif media_type in (3, 4, 5, 8, 9, 10, 13):
                unpacked = struct.unpack("<iiqq", decoded)
                dc_id, document_id, access_hash = unpacked[1:]

                data = FileData(
                    **get_existing_attributes(),
                    media_type=media_type,
                    dc_id=dc_id,
                    document_id=document_id,
                    access_hash=access_hash
                )
            else:
                raise ValueError("Unknown media type: {}".format(file_id_str))
        except (AssertionError, binascii.Error, struct.error):
            raise FileIdInvalid from None

        done = asyncio.Event()
        path = [None]

        directory, file_name = os.path.split(file_name)
        file_name = file_name or data.file_name or ""

        if not os.path.isabs(file_name):
            directory = self.PARENT_DIR / (directory or DEFAULT_DOWNLOAD_DIR)

        media_type_str = self.MEDIA_TYPE_ID[data.media_type]

        if not file_name:
            guessed_extension = self.guess_extension(data.mime_type)

            if data.media_type in (0, 1, 2, 14):
                extension = ".jpg"
            elif data.media_type == 3:
                extension = guessed_extension or ".ogg"
            elif data.media_type in (4, 10, 13):
                extension = guessed_extension or ".mp4"
            elif data.media_type == 5:
                extension = guessed_extension or ".zip"
            elif data.media_type == 8:
                extension = guessed_extension or ".webp"
            elif data.media_type == 9:
                extension = guessed_extension or ".mp3"
            else:
                extension = ".unknown"

            file_name = "{}_{}_{}{}".format(
                media_type_str,
                datetime.fromtimestamp(data.date or time.time()).strftime("%Y-%m-%d_%H-%M-%S"),
                self.rnd_id(),
                extension
            )

        # Cast to string because Path objects aren't supported by Python 3.5
        self.download_queue.put_nowait((data, str(directory), str(file_name), done, progress, progress_args, path))

        if block:
            await done.wait()

        return path[0]