#  Pyrogram - Telegram MTProto API Client Library for Python
#  Copyright (C) 2017-2020 Dan <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 functools
import io
import logging
import math
import os
from hashlib import md5
from pathlib import PurePath
from typing import Union, BinaryIO

from pyrogram import StopTransmission
from pyrogram import raw
from pyrogram.scaffold import Scaffold
from pyrogram.session import Session

log = logging.getLogger(__name__)


class SaveFile(Scaffold):
    async def save_file(
        self,
        path: Union[str, BinaryIO],
        file_id: int = None,
        file_part: int = 0,
        progress: callable = None,
        progress_args: tuple = ()
    ):
        """Upload a file onto Telegram servers, without actually sending the message to anyone.
        Useful whenever an InputFile type is required.

        .. note::

            This is a utility method intended to be used **only** when working with raw
            :obj:`functions <pyrogram.api.functions>` (i.e: a Telegram API method you wish to use which is not
            available yet in the Client class as an easy-to-use method).

        Parameters:
            path (``str``):
                The path of the file you want to upload that exists on your local machine.

            file_id (``int``, *optional*):
                In case a file part expired, pass the file_id and the file_part to retry uploading that specific chunk.

            file_part (``int``, *optional*):
                In case a file part expired, pass the file_id and the file_part to retry uploading that specific chunk.

            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:
            ``InputFile``: On success, the uploaded file is returned in form of an InputFile object.

        Raises:
            RPCError: In case of a Telegram RPC error.
        """
        if path is None:
            return None

        async def worker(session):
            while True:
                data = await queue.get()

                if data is None:
                    return

                try:
                    await asyncio.ensure_future(session.send(data))
                except Exception as e:
                    log.error(e)

        part_size = 512 * 1024

        if isinstance(path, (str, PurePath)):
            fp = open(path, "rb")
        elif isinstance(path, io.IOBase):
            fp = path
        else:
            raise ValueError("Invalid file. Expected a file path as string or a binary (not text) file pointer")

        file_name = fp.name

        fp.seek(0, os.SEEK_END)
        file_size = fp.tell()
        fp.seek(0)

        if file_size == 0:
            raise ValueError("File size equals to 0 B")

        if file_size > 2000 * 1024 * 1024:
            raise ValueError("Telegram doesn't support uploading files bigger than 2000 MiB")

        file_total_parts = int(math.ceil(file_size / part_size))
        is_big = file_size > 10 * 1024 * 1024
        pool_size = 3 if is_big else 1
        workers_count = 4 if is_big else 1
        is_missing_part = file_id is not None
        file_id = file_id or self.rnd_id()
        md5_sum = md5() if not is_big and not is_missing_part else None
        pool = [
            Session(
                self, await self.storage.dc_id(), await self.storage.auth_key(),
                await self.storage.test_mode(), is_media=True
            ) for _ in range(pool_size)
        ]
        workers = [asyncio.ensure_future(worker(session)) for session in pool for _ in range(workers_count)]
        queue = asyncio.Queue(16)

        try:
            for session in pool:
                await session.start()

            with fp:
                fp.seek(part_size * file_part)

                while True:
                    chunk = fp.read(part_size)

                    if not chunk:
                        if not is_big:
                            md5_sum = "".join([hex(i)[2:].zfill(2) for i in md5_sum.digest()])
                        break

                    if is_big:
                        rpc = raw.functions.upload.SaveBigFilePart(
                            file_id=file_id,
                            file_part=file_part,
                            file_total_parts=file_total_parts,
                            bytes=chunk
                        )
                    else:
                        rpc = raw.functions.upload.SaveFilePart(
                            file_id=file_id,
                            file_part=file_part,
                            bytes=chunk
                        )

                    await queue.put(rpc)

                    if is_missing_part:
                        return

                    if not is_big:
                        md5_sum.update(chunk)

                    file_part += 1

                    if progress:
                        if asyncio.iscoroutinefunction(progress):
                            await progress(min(file_part * part_size, file_size), file_size, *progress_args)
                        else:
                            func = functools.partial(
                                progress,
                                min(file_part * part_size, file_size),
                                file_size,
                                *progress_args
                            )

                            await self.loop.run_in_executor(self.executor, func)
        except StopTransmission:
            raise
        except Exception as e:
            log.error(e, exc_info=True)
        else:
            if is_big:
                return raw.types.InputFileBig(
                    id=file_id,
                    parts=file_total_parts,
                    name=file_name,

                )
            else:
                return raw.types.InputFile(
                    id=file_id,
                    parts=file_total_parts,
                    name=file_name,
                    md5_checksum=md5_sum
                )
        finally:
            for _ in workers:
                await queue.put(None)

            await asyncio.gather(*workers)

            for session in pool:
                await session.stop()