import hashlib
import io
import itertools
import os
import pathlib
import re
import typing
import inspect
from io import BytesIO

from .. import utils, helpers, hints
from ..tl import types, functions, custom

try:
    import PIL
    import PIL.Image
except ImportError:
    PIL = None


if typing.TYPE_CHECKING:
    from .telegramclient import TelegramClient


class _CacheType:
    """Like functools.partial but pretends to be the wrapped class."""
    def __init__(self, cls):
        self._cls = cls

    def __call__(self, *args, **kwargs):
        return self._cls(*args, file_reference=b'', **kwargs)

    def __eq__(self, other):
        return self._cls == other


def _resize_photo_if_needed(
        file, is_image, width=1280, height=1280, background=(255, 255, 255)):

    # https://github.com/telegramdesktop/tdesktop/blob/12905f0dcb9d513378e7db11989455a1b764ef75/Telegram/SourceFiles/boxes/photo_crop_box.cpp#L254
    if (not is_image
            or PIL is None
            or (isinstance(file, io.IOBase) and not file.seekable())):
        return file

    if isinstance(file, bytes):
        file = io.BytesIO(file)

    before = file.tell() if isinstance(file, io.IOBase) else None

    try:
        # Don't use a `with` block for `image`, or `file` would be closed.
        # See https://github.com/LonamiWebs/Telethon/issues/1121 for more.
        image = PIL.Image.open(file)
        if image.width <= width and image.height <= height:
            return file

        image.thumbnail((width, height), PIL.Image.ANTIALIAS)

        alpha_index = image.mode.find('A')
        if alpha_index == -1:
            # If the image mode doesn't have alpha
            # channel then don't bother masking it away.
            result = image
        else:
            # We could save the resized image with the original format, but
            # JPEG often compresses better -> smaller size -> faster upload
            # We need to mask away the alpha channel ([3]), since otherwise
            # IOError is raised when trying to save alpha channels in JPEG.
            result = PIL.Image.new('RGB', image.size, background)
            result.paste(image, mask=image.split()[alpha_index])

        buffer = io.BytesIO()
        result.save(buffer, 'JPEG')
        buffer.seek(0)
        return buffer

    except IOError:
        return file
    finally:
        if before is not None:
            file.seek(before, io.SEEK_SET)


class UploadMethods:

    # region Public methods

    async def send_file(
            self: 'TelegramClient',
            entity: 'hints.EntityLike',
            file: 'typing.Union[hints.FileLike, typing.Sequence[hints.FileLike]]',
            *,
            caption: typing.Union[str, typing.Sequence[str]] = None,
            force_document: bool = False,
            clear_draft: bool = False,
            progress_callback: 'hints.ProgressCallback' = None,
            reply_to: 'hints.MessageIDLike' = None,
            attributes: 'typing.Sequence[types.TypeDocumentAttribute]' = None,
            thumb: 'hints.FileLike' = None,
            allow_cache: bool = True,
            parse_mode: str = (),
            voice_note: bool = False,
            video_note: bool = False,
            buttons: 'hints.MarkupLike' = None,
            silent: bool = None,
            supports_streaming: bool = False,
            schedule: 'hints.DateLike' = None,
            **kwargs) -> 'types.Message':
        """
        Sends message with the given file to the specified entity.

        .. note::

            If the ``hachoir3`` package (``hachoir`` module) is installed,
            it will be used to determine metadata from audio and video files.

            If the ``pillow`` package is installed and you are sending a photo,
            it will be resized to fit within the maximum dimensions allowed
            by Telegram to avoid ``errors.PhotoInvalidDimensionsError``. This
            cannot be done if you are sending :tl:`InputFile`, however.

        Arguments
            entity (`entity`):
                Who will receive the file.

            file (`str` | `bytes` | `file` | `media`):
                The file to send, which can be one of:

                * A local file path to an in-disk file. The file name
                  will be the path's base name.

                * A `bytes` byte array with the file's data to send
                  (for example, by using ``text.encode('utf-8')``).
                  A default file name will be used.

                * A bytes `io.IOBase` stream over the file to send
                  (for example, by using ``open(file, 'rb')``).
                  Its ``.name`` property will be used for the file name,
                  or a default if it doesn't have one.

                * An external URL to a file over the internet. This will
                  send the file as "external" media, and Telegram is the
                  one that will fetch the media and send it.

                * A Bot API-like ``file_id``. You can convert previously
                  sent media to file IDs for later reusing with
                  `telethon.utils.pack_bot_file_id`.

                * A handle to an existing file (for example, if you sent a
                  message with media before, you can use its ``message.media``
                  as a file here).

                * A handle to an uploaded file (from `upload_file`).

                To send an album, you should provide a list in this parameter.

                If a list or similar is provided, the files in it will be
                sent as an album in the order in which they appear, sliced
                in chunks of 10 if more than 10 are given.

            caption (`str`, optional):
                Optional caption for the sent media message. When sending an
                album, the caption may be a list of strings, which will be
                assigned to the files pairwise.

            force_document (`bool`, optional):
                If left to `False` and the file is a path that ends with
                the extension of an image file or a video file, it will be
                sent as such. Otherwise always as a document.

            clear_draft (`bool`, optional):
                Whether the existing draft should be cleared or not.

            progress_callback (`callable`, optional):
                A callback function accepting two parameters:
                ``(sent bytes, total)``.

            reply_to (`int` | `Message <telethon.tl.custom.message.Message>`):
                Same as `reply_to` from `send_message`.

            attributes (`list`, optional):
                Optional attributes that override the inferred ones, like
                :tl:`DocumentAttributeFilename` and so on.

            thumb (`str` | `bytes` | `file`, optional):
                Optional JPEG thumbnail (for documents). **Telegram will
                ignore this parameter** unless you pass a ``.jpg`` file!

                The file must also be small in dimensions and in-disk size.
                Successful thumbnails were files below 20kb and 200x200px.
                Width/height and dimensions/size ratios may be important.

            allow_cache (`bool`, optional):
                This parameter currently does nothing, but is kept for
                backward-compatibility (and it may get its use back in
                the future).

            parse_mode (`object`, optional):
                See the `TelegramClient.parse_mode
                <telethon.client.messageparse.MessageParseMethods.parse_mode>`
                property for allowed values. Markdown parsing will be used by
                default.

            voice_note (`bool`, optional):
                If `True` the audio will be sent as a voice note.

            video_note (`bool`, optional):
                If `True` the video will be sent as a video note,
                also known as a round video message.

            buttons (`list`, `custom.Button <telethon.tl.custom.button.Button>`, :tl:`KeyboardButton`):
                The matrix (list of lists), row list or button to be shown
                after sending the message. This parameter will only work if
                you have signed in as a bot. You can also pass your own
                :tl:`ReplyMarkup` here.

            silent (`bool`, optional):
                Whether the message should notify people with sound or not.
                Defaults to `False` (send with a notification sound unless
                the person has the chat muted). Set it to `True` to alter
                this behaviour.

            supports_streaming (`bool`, optional):
                Whether the sent video supports streaming or not. Note that
                Telegram only recognizes as streamable some formats like MP4,
                and others like AVI or MKV will not work. You should convert
                these to MP4 before sending if you want them to be streamable.
                Unsupported formats will result in ``VideoContentTypeError``.

            schedule (`hints.DateLike`, optional):
                If set, the file won't send immediately, and instead
                it will be scheduled to be automatically sent at a later
                time.

        Returns
            The `Message <telethon.tl.custom.message.Message>` (or messages)
            containing the sent file, or messages if a list of them was passed.

        Example
            .. code-block:: python

                # Normal files like photos
                await client.send_file(chat, '/my/photos/me.jpg', caption="It's me!")
                # or
                await client.send_message(chat, "It's me!", file='/my/photos/me.jpg')

                # Voice notes or round videos
                await client.send_file(chat, '/my/songs/song.mp3', voice_note=True)
                await client.send_file(chat, '/my/videos/video.mp4', video_note=True)

                # Custom thumbnails
                await client.send_file(chat, '/my/documents/doc.txt', thumb='photo.jpg')

                # Only documents
                await client.send_file(chat, '/my/photos/photo.png', force_document=True)

                # Albums
                await client.send_file(chat, [
                    '/my/photos/holiday1.jpg',
                    '/my/photos/holiday2.jpg',
                    '/my/drawings/portrait.png'
                ])
        """
        # TODO Properly implement allow_cache to reuse the sha256 of the file
        # i.e. `None` was used
        if not file:
            raise TypeError('Cannot use {!r} as file'.format(file))

        if not caption:
            caption = ''

        # First check if the user passed an iterable, in which case
        # we may want to send as an album if all are photo files.
        if utils.is_list_like(file):
            media_captions = []
            document_captions = []
            if utils.is_list_like(caption):
                captions = caption
            else:
                captions = [caption]

            # TODO Fix progress_callback
            media = []
            if force_document:
                documents = file
            else:
                documents = []
                for doc, cap in itertools.zip_longest(file, captions):
                    if utils.is_image(doc) or utils.is_video(doc):
                        media.append(doc)
                        media_captions.append(cap)
                    else:
                        documents.append(doc)
                        document_captions.append(cap)

            result = []
            while media:
                result += await self._send_album(
                    entity, media[:10], caption=media_captions[:10],
                    progress_callback=progress_callback, reply_to=reply_to,
                    parse_mode=parse_mode, silent=silent, schedule=schedule,
                    supports_streaming=supports_streaming, clear_draft=clear_draft
                )
                media = media[10:]
                media_captions = media_captions[10:]

            for doc, cap in zip(documents, captions):
                result.append(await self.send_file(
                    entity, doc, allow_cache=allow_cache,
                    caption=cap, force_document=force_document,
                    progress_callback=progress_callback, reply_to=reply_to,
                    attributes=attributes, thumb=thumb, voice_note=voice_note,
                    video_note=video_note, buttons=buttons, silent=silent,
                    supports_streaming=supports_streaming, schedule=schedule,
                    clear_draft=clear_draft,
                    **kwargs
                ))

            return result

        entity = await self.get_input_entity(entity)
        reply_to = utils.get_message_id(reply_to)

        # Not document since it's subject to change.
        # Needed when a Message is passed to send_message and it has media.
        if 'entities' in kwargs:
            msg_entities = kwargs['entities']
        else:
            caption, msg_entities =\
                await self._parse_message_text(caption, parse_mode)

        file_handle, media, image = await self._file_to_media(
            file, force_document=force_document,
            progress_callback=progress_callback,
            attributes=attributes,  allow_cache=allow_cache, thumb=thumb,
            voice_note=voice_note, video_note=video_note,
            supports_streaming=supports_streaming
        )

        # e.g. invalid cast from :tl:`MessageMediaWebPage`
        if not media:
            raise TypeError('Cannot use {!r} as file'.format(file))

        markup = self.build_reply_markup(buttons)
        request = functions.messages.SendMediaRequest(
            entity, media, reply_to_msg_id=reply_to, message=caption,
            entities=msg_entities, reply_markup=markup, silent=silent,
            schedule_date=schedule, clear_draft=clear_draft
        )
        msg = self._get_response_message(request, await self(request), entity)
        await self._cache_media(msg, file, file_handle, image=image)

        return msg

    async def _send_album(self: 'TelegramClient', entity, files, caption='',
                          progress_callback=None, reply_to=None,
                          parse_mode=(), silent=None, schedule=None,
                          supports_streaming=None, clear_draft=None):
        """Specialized version of .send_file for albums"""
        # We don't care if the user wants to avoid cache, we will use it
        # anyway. Why? The cached version will be exactly the same thing
        # we need to produce right now to send albums (uploadMedia), and
        # cache only makes a difference for documents where the user may
        # want the attributes used on them to change.
        #
        # In theory documents can be sent inside the albums but they appear
        # as different messages (not inside the album), and the logic to set
        # the attributes/avoid cache is already written in .send_file().
        entity = await self.get_input_entity(entity)
        if not utils.is_list_like(caption):
            caption = (caption,)

        captions = []
        for c in reversed(caption):  # Pop from the end (so reverse)
            captions.append(await self._parse_message_text(c or '', parse_mode))

        reply_to = utils.get_message_id(reply_to)

        # Need to upload the media first, but only if they're not cached yet
        media = []
        for file in files:
            # Albums want :tl:`InputMedia` which, in theory, includes
            # :tl:`InputMediaUploadedPhoto`. However using that will
            # make it `raise MediaInvalidError`, so we need to upload
            # it as media and then convert that to :tl:`InputMediaPhoto`.
            fh, fm, _ = await self._file_to_media(
                file, supports_streaming=supports_streaming)
            if isinstance(fm, types.InputMediaUploadedPhoto):
                r = await self(functions.messages.UploadMediaRequest(
                    entity, media=fm
                ))
                self.session.cache_file(
                    fh.md5, fh.size, utils.get_input_photo(r.photo))

                fm = utils.get_input_media(r.photo)
            elif isinstance(fm, types.InputMediaUploadedDocument):
                r = await self(functions.messages.UploadMediaRequest(
                    entity, media=fm
                ))
                self.session.cache_file(
                    fh.md5, fh.size, utils.get_input_document(r.document))

                fm = utils.get_input_media(
                    r.document, supports_streaming=supports_streaming)

            if captions:
                caption, msg_entities = captions.pop()
            else:
                caption, msg_entities = '', None
            media.append(types.InputSingleMedia(
                fm,
                message=caption,
                entities=msg_entities
                # random_id is autogenerated
            ))

        # Now we can construct the multi-media request
        request = functions.messages.SendMultiMediaRequest(
            entity, reply_to_msg_id=reply_to, multi_media=media,
            silent=silent, schedule_date=schedule, clear_draft=clear_draft
        )
        result = await self(request)

        random_ids = [m.random_id for m in media]
        return self._get_response_message(random_ids, result, entity)

    async def upload_file(
            self: 'TelegramClient',
            file: 'hints.FileLike',
            *,
            part_size_kb: float = None,
            file_name: str = None,
            use_cache: type = None,
            progress_callback: 'hints.ProgressCallback' = None) -> 'types.TypeInputFile':
        """
        Uploads a file to Telegram's servers, without sending it.

        This method returns a handle (an instance of :tl:`InputFile` or
        :tl:`InputFileBig`, as required) which can be later used before
        it expires (they are usable during less than a day).

        Uploading a file will simply return a "handle" to the file stored
        remotely in the Telegram servers, which can be later used on. This
        will **not** upload the file to your own chat or any chat at all.

        Arguments
            file (`str` | `bytes` | `file`):
                The path of the file, byte array, or stream that will be sent.
                Note that if a byte array or a stream is given, a filename
                or its type won't be inferred, and it will be sent as an
                "unnamed application/octet-stream".

            part_size_kb (`int`, optional):
                Chunk size when uploading files. The larger, the less
                requests will be made (up to 512KB maximum).

            file_name (`str`, optional):
                The file name which will be used on the resulting InputFile.
                If not specified, the name will be taken from the ``file``
                and if this is not a `str`, it will be ``"unnamed"``.

            use_cache (`type`, optional):
                This parameter currently does nothing, but is kept for
                backward-compatibility (and it may get its use back in
                the future).

            progress_callback (`callable`, optional):
                A callback function accepting two parameters:
                ``(sent bytes, total)``.

        Returns
            :tl:`InputFileBig` if the file size is larger than 10MB,
            `InputSizedFile <telethon.tl.custom.inputsizedfile.InputSizedFile>`
            (subclass of :tl:`InputFile`) otherwise.

        Example
            .. code-block:: python

                # Photos as photo and document
                file = await client.upload_file('photo.jpg')
                await client.send_file(chat, file)                       # sends as photo
                await client.send_file(chat, file, force_document=True)  # sends as document

                file.name = 'not a photo.jpg'
                await client.send_file(chat, file, force_document=True)  # document, new name

                # As song or as voice note
                file = await client.upload_file('song.ogg')
                await client.send_file(chat, file)                   # sends as song
                await client.send_file(chat, file, voice_note=True)  # sends as voice note
        """
        if isinstance(file, (types.InputFile, types.InputFileBig)):
            return file  # Already uploaded

        if not file_name and getattr(file, 'name', None):
            file_name = file.name

        if isinstance(file, str):
            file_size = os.path.getsize(file)
        elif isinstance(file, bytes):
            file_size = len(file)
        else:
            # `aiofiles` shouldn't base `IOBase` because they change the
            # methods' definition. `seekable` would be `async` but since
            # we won't get to check that, there's no need to maybe-await.
            if isinstance(file, io.IOBase) and file.seekable():
                pos = file.tell()
            else:
                pos = None

            # TODO Don't load the entire file in memory always
            data = file.read()
            if inspect.isawaitable(data):
                data = await data

            if pos is not None:
                file.seek(pos)

            if not isinstance(data, bytes):
                raise TypeError(
                    'file descriptor returned {}, not bytes (you must '
                    'open the file in bytes mode)'.format(type(data)))

            file = data
            file_size = len(file)

        # File will now either be a string or bytes
        if not part_size_kb:
            part_size_kb = utils.get_appropriated_part_size(file_size)

        if part_size_kb > 512:
            raise ValueError('The part size must be less or equal to 512KB')

        part_size = int(part_size_kb * 1024)
        if part_size % 1024 != 0:
            raise ValueError(
                'The part size must be evenly divisible by 1024')

        # Set a default file name if None was specified
        file_id = helpers.generate_random_long()
        if not file_name:
            if isinstance(file, str):
                file_name = os.path.basename(file)
            else:
                file_name = str(file_id)

        # If the file name lacks extension, add it if possible.
        # Else Telegram complains with `PHOTO_EXT_INVALID_ERROR`
        # even if the uploaded image is indeed a photo.
        if not os.path.splitext(file_name)[-1]:
            file_name += utils._get_extension(file)

        # Determine whether the file is too big (over 10MB) or not
        # Telegram does make a distinction between smaller or larger files
        is_large = file_size > 10 * 1024 * 1024
        hash_md5 = hashlib.md5()
        if not is_large:
            # Calculate the MD5 hash before anything else.
            # As this needs to be done always for small files,
            # might as well do it before anything else and
            # check the cache.
            if isinstance(file, str):
                with open(file, 'rb') as stream:
                    file = stream.read()
            hash_md5.update(file)

        part_count = (file_size + part_size - 1) // part_size
        self._log[__name__].info('Uploading file of %d bytes in %d chunks of %d',
                                 file_size, part_count, part_size)

        with open(file, 'rb') if isinstance(file, str) else BytesIO(file)\
                as stream:
            for part_index in range(part_count):
                # Read the file by in chunks of size part_size
                part = stream.read(part_size)

                # The SavePartRequest is different depending on whether
                # the file is too large or not (over or less than 10MB)
                if is_large:
                    request = functions.upload.SaveBigFilePartRequest(
                        file_id, part_index, part_count, part)
                else:
                    request = functions.upload.SaveFilePartRequest(
                        file_id, part_index, part)

                result = await self(request)
                if result:
                    self._log[__name__].debug('Uploaded %d/%d',
                                              part_index + 1, part_count)
                    if progress_callback:
                        r = progress_callback(stream.tell(), file_size)
                        if inspect.isawaitable(r):
                            await r
                else:
                    raise RuntimeError(
                        'Failed to upload file part {}.'.format(part_index))

        if is_large:
            return types.InputFileBig(file_id, part_count, file_name)
        else:
            return custom.InputSizedFile(
                file_id, part_count, file_name, md5=hash_md5, size=file_size
            )

    # endregion

    async def _file_to_media(
            self, file, force_document=False,
            progress_callback=None, attributes=None, thumb=None,
            allow_cache=True, voice_note=False, video_note=False,
            supports_streaming=False, mime_type=None, as_image=None):
        if not file:
            return None, None, None

        if isinstance(file, pathlib.Path):
            file = str(file.absolute())

        if as_image is None:
            as_image = utils.is_image(file) and not force_document

        # `aiofiles` do not base `io.IOBase` but do have `read`, so we
        # just check for the read attribute to see if it's file-like.
        if not isinstance(file, (str, bytes)) and not hasattr(file, 'read'):
            # The user may pass a Message containing media (or the media,
            # or anything similar) that should be treated as a file. Try
            # getting the input media for whatever they passed and send it.
            #
            # We pass all attributes since these will be used if the user
            # passed :tl:`InputFile`, and all information may be relevant.
            try:
                return (None, utils.get_input_media(
                    file,
                    is_photo=as_image,
                    attributes=attributes,
                    force_document=force_document,
                    voice_note=voice_note,
                    video_note=video_note,
                    supports_streaming=supports_streaming
                ), as_image)
            except TypeError:
                # Can't turn whatever was given into media
                return None, None, as_image

        media = None
        file_handle = None
        if not isinstance(file, str) or os.path.isfile(file):
            file_handle = await self.upload_file(
                _resize_photo_if_needed(file, as_image),
                progress_callback=progress_callback
            )
        elif re.match('https?://', file):
            if as_image:
                media = types.InputMediaPhotoExternal(file)
            elif not force_document and utils.is_gif(file):
                media = types.InputMediaGifExternal(file, '')
            else:
                media = types.InputMediaDocumentExternal(file)
        else:
            bot_file = utils.resolve_bot_file_id(file)
            if bot_file:
                media = utils.get_input_media(bot_file)

        if media:
            pass  # Already have media, don't check the rest
        elif not file_handle:
            raise ValueError(
                'Failed to convert {} to media. Not an existing file, '
                'an HTTP URL or a valid bot-API-like file ID'.format(file)
            )
        elif as_image:
            media = types.InputMediaUploadedPhoto(file_handle)
        else:
            attributes, mime_type = utils.get_attributes(
                file,
                mime_type=mime_type,
                attributes=attributes,
                force_document=force_document,
                voice_note=voice_note,
                video_note=video_note,
                supports_streaming=supports_streaming
            )

            input_kw = {}
            if thumb:
                if isinstance(thumb, pathlib.Path):
                    thumb = str(thumb.absolute())
                input_kw['thumb'] = await self.upload_file(thumb)

            media = types.InputMediaUploadedDocument(
                file=file_handle,
                mime_type=mime_type,
                attributes=attributes,
                **input_kw
            )
        return file_handle, media, as_image

    async def _cache_media(self: 'TelegramClient', msg, file, file_handle, image):
        if file and msg and isinstance(file_handle,
                                       custom.InputSizedFile):
            # There was a response message and we didn't use cached
            # version, so cache whatever we just sent to the database.
            md5, size = file_handle.md5, file_handle.size
            if image:
                to_cache = utils.get_input_photo(msg.media.photo)
            else:
                to_cache = utils.get_input_document(msg.media.document)
            self.session.cache_file(md5, size, to_cache)

    # endregion
