from asyncio import TimeoutError
import glob
from itertools import chain
import os
from pathlib import Path, PurePosixPath
import posixpath
import re
import tarfile
import time
from typing import List, Optional, Tuple, Union

from aiohttp.client_exceptions import ClientError
import fsspec

from datalabs import config
from datalabs.filesystems import COMPRESSION_FILESYSTEMS
from datalabs.utils.download_manager import DownloadConfig, map_nested
from datalabs.utils.file_utils import (
    get_authentication_headers_for_url,
    http_head,
    is_local_path,
    is_relative_path,
    is_remote_url,
    url_or_path_join,
)
from datalabs.utils.logging import get_logger

logger = get_logger(__name__)

BASE_KNOWN_EXTENSIONS = [
    "txt",
    "csv",
    "json",
    "jsonl",
    "tsv",
    "conll",
    "conllu",
    "orig",
    "parquet",
    "pkl",
    "pickle",
    "rel",
    "xml",
]
COMPRESSION_EXTENSION_TO_PROTOCOL = {
    # single file compression
    **{
        fs_class.extension.lstrip("."): fs_class.protocol
        for fs_class in COMPRESSION_FILESYSTEMS
    },
    # archive compression
    "zip": "zip",
    "tar": "tar",
    "tgz": "tar",
}
SINGLE_FILE_COMPRESSION_PROTOCOLS = {
    fs_class.protocol for fs_class in COMPRESSION_FILESYSTEMS
}
SINGLE_SLASH_AFTER_PROTOCOL_PATTERN = re.compile(r"(?<!:):/")


MAGIC_NUMBER_TO_COMPRESSION_PROTOCOL = {
    bytes.fromhex("504B0304"): "zip",
    bytes.fromhex("504B0506"): "zip",  # empty archive
    bytes.fromhex("504B0708"): "zip",  # spanned archive
    bytes.fromhex("425A68"): "bz2",
    bytes.fromhex("1F8B"): "gzip",
    bytes.fromhex("FD377A585A00"): "xz",
    bytes.fromhex("04224D18"): "lz4",
    bytes.fromhex("28B52FFD"): "zstd",
}
MAGIC_NUMBER_TO_UNSUPPORTED_COMPRESSION_PROTOCOL = {
    b"Rar!": "rar",
}
MAGIC_NUMBER_MAX_LENGTH = max(
    len(magic_number)
    for magic_number in chain(
        MAGIC_NUMBER_TO_COMPRESSION_PROTOCOL,
        MAGIC_NUMBER_TO_UNSUPPORTED_COMPRESSION_PROTOCOL,
    )
)


def xjoin(a, *p):
    """
    This function extends os.path.join to support the "::" hop
    separator. It supports both paths and urls.

    A shorthand, particularly useful where you have multiple hops,
     is to “chain” the URLs with the special separator "::".
    This is used to access files inside a zip file over http for
     example.

    Let's say you have a zip file at https://host.com/archive.zip
    , and you want to access the file inside the zip file at /folder1/file.txt.
    Then you can just chain the url this way:

        zip://folder1/file.txt::https://host.com/archive.zip

    The xjoin function allows you to apply the join on the first path of the chain.

    Example::

        >>> xjoin("zip://folder1::https://host.com/archive.zip", "file.txt")
        zip://folder1/file.txt::https://host.com/archive.zip
    """
    a, *b = a.split("::")
    if is_local_path(a):
        a = Path(a, *p).as_posix()
    else:
        a = posixpath.join(a, *p)
    return "::".join([a] + b)


def xdirname(a):
    """
    This function extends os.path.dirname to support the "::" hop separator.
     It supports both paths and urls.

    A shorthand, particularly useful where you have multiple hops, is
     to “chain” the URLs with the special separator "::".
    This is used to access files inside a zip file over http for example.

    Let's say you have a zip file at https://host.com/archive.zip, and
     you want to access the file inside the zip file at /folder1/file.txt.
    Then you can just chain the url this way:

        zip://folder1/file.txt::https://host.com/archive.zip

    The xdirname function allows you to apply the dirname on the
     first path of the chain.

    Example::

        >>> xdirname("zip://folder1/file.txt::https://host.com/archive.zip")
        zip://folder1::https://host.com/archive.zip
    """
    a, *b = a.split("::")
    if is_local_path(a):
        a = os.path.dirname(Path(a).as_posix())
    else:
        a = posixpath.dirname(a)
    # if we end up at the root of the protocol, we get for example a = 'http:'
    # so we have to fix it by adding the '//' that was removed:
    if a.endswith(":"):
        a += "//"
    return "::".join([a] + b)


def xbasename(a):
    """
    This function extends os.path.basename to support the "::" hop separator.
     It supports both paths and urls.

    A shorthand, particularly useful where you have multiple hops, is to
     “chain” the URLs with the special separator "::".
    This is used to access files inside a zip file over http for example.

    Let's say you have a zip file at https://host.com/archive.zip,
    and you want to access the file inside the zip file at /folder1/file.txt.
    Then you can just chain the url this way:

        zip://folder1/file.txt::https://host.com/archive.zip

    The xbasename function allows you to apply the basename on the
    first path of the chain.

    Example::

        >>> xbasename("zip://folder1/file.txt::https://host.com/archive.zip")
        file.txt
    """
    a, *b = a.split("::")
    if is_local_path(a):
        return os.path.basename(Path(a).as_posix())
    else:
        return posixpath.basename(a)


def _as_posix(path: Path):
    """Extend :meth:`pathlib.PurePath.as_posix` to fix missing slashes after protocol.

    Args:
        path (:obj:`~pathlib.Path`): Calling Path instance.

    Returns:
        obj:`str`
    """
    path_as_posix = path.as_posix()
    path_as_posix = SINGLE_SLASH_AFTER_PROTOCOL_PATTERN.sub("://", path_as_posix)
    path_as_posix += (
        "//" if path_as_posix.endswith(":") else ""
    )  # Add slashes to root of the protocol
    return path_as_posix


def xpathjoin(a: Path, *p: Tuple[str, ...]):
    """Extend :func:`xjoin` to support argument of type :obj:`~pathlib.Path`.

    Args:
        a (:obj:`~pathlib.Path`): Calling Path instance.
        *p (:obj:`tuple` of :obj:`str`): Other path components.

    Returns:
        obj:`str`
    """
    return type(a)(xjoin(_as_posix(a), *p))


def _add_retries_to_file_obj_read_method(file_obj):
    read = file_obj.read
    max_retries = config.STREAMING_READ_MAX_RETRIES

    def read_with_retries(*args, **kwargs):
        for retry in range(1, max_retries + 1):
            try:
                out = read(*args, **kwargs)
                break
            except (ClientError, TimeoutError):
                logger.warning(
                    f"Got disconnected from remote data host. "
                    f"Retrying in {config.STREAMING_READ_RETRY_INTERVAL}sec"
                    f" [{retry}/{max_retries}]"
                )
                time.sleep(config.STREAMING_READ_RETRY_INTERVAL)
        else:
            raise ConnectionError("Server Disconnected")
        return out

    file_obj.read = read_with_retries


def _get_extraction_protocol_with_magic_number(f) -> Optional[str]:
    """read the magic number from a file-like object and return
    the compression protocol"""
    prev_loc = f.loc
    magic_number = f.read(MAGIC_NUMBER_MAX_LENGTH)
    f.seek(prev_loc)
    for i in range(MAGIC_NUMBER_MAX_LENGTH):
        compression = MAGIC_NUMBER_TO_COMPRESSION_PROTOCOL.get(
            magic_number[: MAGIC_NUMBER_MAX_LENGTH - i]
        )
        if (
            compression is not None
        ):  # TODO(QL): raise an error for .tar.gz files as in _get_extraction_protocol
            return compression
        compression = MAGIC_NUMBER_TO_UNSUPPORTED_COMPRESSION_PROTOCOL.get(
            magic_number[: MAGIC_NUMBER_MAX_LENGTH - i]
        )
        if compression is not None:
            raise NotImplementedError(
                f"Compression protocol '{compression}' not implemented."
            )


def _get_extraction_protocol(
    urlpath: str, use_auth_token: Optional[Union[str, bool]] = None
) -> Optional[str]:
    # get inner file: zip://train-00000.json.gz::https://foo.bar/data.zip
    # -> zip://train-00000.json.gz
    path = urlpath.split("::")[0]
    # Get extension: https://foo.bar/train.json.gz -> gz
    extension = path.split(".")[-1]
    # Remove query params ("dl=1", "raw=true"): gz?dl=1 -> gz
    # Remove shards infos (".txt_1", ".txt-00000-of-00100"): txt_1 -> txt
    for symb in "?-_":
        extension = extension.split(symb)[0]
    if extension in BASE_KNOWN_EXTENSIONS:
        return None
    elif path.endswith(".tar.gz") or path.endswith(".tgz"):
        raise NotImplementedError(
            f"Extraction protocol for TAR archives like '{urlpath}' is "
            f"not implemented in streaming mode. Please use "
            f"`dl_manager.iter_archive` instead."
        )
    elif extension in COMPRESSION_EXTENSION_TO_PROTOCOL:
        return COMPRESSION_EXTENSION_TO_PROTOCOL[extension]

    if is_remote_url(urlpath):
        # get headers and cookies for authentication on the HF Hub and for Google Drive
        urlpath, kwargs = _prepare_http_url_kwargs(
            urlpath, use_auth_token=use_auth_token
        )
    else:
        urlpath, kwargs = urlpath, {}
    with fsspec.open(urlpath, **kwargs) as f:
        return _get_extraction_protocol_with_magic_number(f)


def _prepare_http_url_kwargs(
    url: str, use_auth_token: Optional[Union[str, bool]] = None
) -> Tuple[str, dict]:
    """
    Prepare the URL and the kwargs that must be passed to the
     HttpFileSystem or to requests.get/head

    In particular it resolves google drive URLs and it adds
     the authentication headers for the Hugging Face Hub.
    """
    kwargs = {
        "headers": get_authentication_headers_for_url(
            url, use_auth_token=use_auth_token
        )
    }
    if "drive.google.com" in url:
        response = http_head(url)
        cookies = None
        for k, v in response.cookies.items():
            if k.startswith("download_warning"):
                url += "&confirm=" + v
                cookies = response.cookies
                kwargs["cookies"] = cookies
    if url.startswith("https://raw.githubusercontent.com/"):
        # Workaround for served data with gzip content-encoding:
        # https://github.com/fsspec/filesystem_spec/issues/389
        kwargs["block_size"] = 0
    return url, kwargs


def xopen(
    file: str,
    mode="r",
    *args,
    use_auth_token: Optional[Union[str, bool]] = None,
    **kwargs,
):
    """
    This function extends the builtin `open` function to support remote
     files using fsspec.

    It also has a retry mechanism in case connection fails.
    The args and kwargs are passed to fsspec.open, except `use_auth_token`
     which is used for queries to private repos on huggingface.co
    """
    main_hop, *rest_hops = file.split("::")
    # add headers and cookies for authentication on the HF Hub and for Google Drive
    if not rest_hops and (
        main_hop.startswith("http://") or main_hop.startswith("https://")
    ):
        file, new_kwargs = _prepare_http_url_kwargs(file, use_auth_token=use_auth_token)
    elif rest_hops and (
        rest_hops[0].startswith("http://") or rest_hops[0].startswith("https://")
    ):
        url = rest_hops[0]
        url, http_kwargs = _prepare_http_url_kwargs(url, use_auth_token=use_auth_token)
        new_kwargs = {"https": http_kwargs}
        file = "::".join([main_hop, url, *rest_hops[1:]])
    else:
        new_kwargs = {}
    kwargs = {**kwargs, **new_kwargs}
    file_obj = fsspec.open(file, mode=mode, *args, **kwargs).open()
    _add_retries_to_file_obj_read_method(file_obj)
    return file_obj


def xlistdir(path: str, use_auth_token: Optional[Union[str, bool]] = None) -> List[str]:
    """Extend `os.listdir` function to support remote files.

    Args:
        path (:obj:`str`): URL path.

    Returns:
        :obj:`list` of :obj:`str`
    """
    main_hop, *rest_hops = path.split("::")
    if is_local_path(main_hop):
        return os.listdir(path)
    else:
        # globbing inside a zip in a private repo requires authentication
        if rest_hops and fsspec.get_fs_token_paths(rest_hops[0])[0].protocol == "https":
            storage_options = {
                "https": {
                    "headers": get_authentication_headers_for_url(
                        rest_hops[0], use_auth_token=use_auth_token
                    )
                }
            }
        else:
            storage_options = None
        fs, *_ = fsspec.get_fs_token_paths(path, storage_options=storage_options)
        objects = fs.listdir(main_hop.split("://")[1])
        return [os.path.basename(obj["name"]) for obj in objects]


def xpathopen(path: Path, *args, **kwargs):
    """Extend :func:`xopen` to support argument of type :obj:`~pathlib.Path`.

    Args:
        path (:obj:`~pathlib.Path`): Calling Path instance.
        **kwargs: Keyword arguments passed to :func:`fsspec.open`.

    Returns:
        :obj:`io.FileIO`: File-like object.
    """
    return xopen(_as_posix(path), *args, **kwargs)


def xglob(
    urlpath, *, recursive=False, use_auth_token: Optional[Union[str, bool]] = None
):
    """Extend `glob.glob` function to support remote files.

    Args:
        urlpath (:obj:`str`): URL path with shell-style wildcard patterns.
        recursive (:obj:`bool`, default `False`):
        Whether to match the "**" pattern recursively to zero or more
            directories or subdirectories.

    Returns:
        :obj:`list` of :obj:`str`
    """
    main_hop, *rest_hops = urlpath.split("::")
    if is_local_path(main_hop):
        return glob.glob(main_hop, recursive=recursive)
    else:
        # globbing inside a zip in a private repo requires authentication
        if rest_hops and (
            rest_hops[0].startswith("http://") or rest_hops[0].startswith("https://")
        ):
            url = rest_hops[0]
            url, kwargs = _prepare_http_url_kwargs(url, use_auth_token=use_auth_token)
            storage_options = {"https": kwargs}
            urlpath = "::".join([main_hop, url, *rest_hops[1:]])
        else:
            storage_options = None
        fs, *_ = fsspec.get_fs_token_paths(urlpath, storage_options=storage_options)
        # - If there's no "*" in the pattern, get_fs_token_paths()
        # doesn't do any pattern matching
        #   so to be able to glob patterns like "[0-9]", we have to call `fs.glob`.
        # - Also "*" in get_fs_token_paths() only matches files:
        # we have to call `fs.glob` to match directories.
        # - If there is "**" in the pattern, `fs.glob` must be called anyway.
        globbed_paths = fs.glob(main_hop)
        return [
            "::".join([f"{fs.protocol}://{globbed_path}"] + rest_hops)
            for globbed_path in globbed_paths
        ]


def xpathglob(path, pattern, use_auth_token: Optional[Union[str, bool]] = None):
    """Glob function for argument of type :obj:`~pathlib.Path` that
    supports both local paths end remote URLs.

    Args:
        path (:obj:`~pathlib.Path`): Calling Path instance.
        pattern (:obj:`str`): Pattern that resulting paths must match.

    Yields:
        :obj:`~pathlib.Path`
    """
    posix_path = _as_posix(path)
    main_hop, *rest_hops = posix_path.split("::")
    if is_local_path(main_hop):
        yield from Path(main_hop).glob(pattern)
    else:
        # globbing inside a zip in a private repo requires authentication
        if rest_hops and (
            rest_hops[0].startswith("http://") or rest_hops[0].startswith("https://")
        ):
            url = rest_hops[0]
            url, kwargs = _prepare_http_url_kwargs(url, use_auth_token=use_auth_token)
            storage_options = {"https": kwargs}
            posix_path = "::".join([main_hop, url, *rest_hops[1:]])
        else:
            storage_options = None
        fs, *_ = fsspec.get_fs_token_paths(
            xjoin(posix_path, pattern), storage_options=storage_options
        )
        # - If there's no "*" in the pattern, get_fs_token_paths() doesn't
        # do any pattern matching
        #   so to be able to glob patterns like "[0-9]", we have to call `fs.glob`.
        # - Also "*" in get_fs_token_paths() only matches files: we have
        # to call `fs.glob` to match directories.
        # - If there is "**" in the pattern, `fs.glob` must be called anyway.
        globbed_paths = fs.glob(xjoin(main_hop, pattern))
        for globbed_path in globbed_paths:
            yield type(path)("::".join([f"{fs.protocol}://{globbed_path}"] + rest_hops))


def xpathrglob(path, pattern, **kwargs):
    """Rglob function for argument of type :obj:`~pathlib.Path` that supports
     both local paths end remote URLs.

    Args:
        path (:obj:`~pathlib.Path`): Calling Path instance.
        pattern (:obj:`str`): Pattern that resulting paths must match.

    Yields:
        :obj:`~pathlib.Path`
    """
    return xpathglob(path, "**/" + pattern, **kwargs)


def xpathstem(path: Path):
    """Stem function for argument of type :obj:`~pathlib.Path` that supports
     both local paths end remote URLs.

    Args:
        path (:obj:`~pathlib.Path`): Calling Path instance.

    Returns:
        :obj:`str`
    """
    return PurePosixPath(_as_posix(path).split("::")[0]).stem


def xpathsuffix(path: Path):
    """Suffix function for argument of type :obj:`~pathlib.Path` that
    supports both local paths end remote URLs.

    Args:
        path (:obj:`~pathlib.Path`): Calling Path instance.

    Returns:
        :obj:`str`
    """
    return PurePosixPath(_as_posix(path).split("::")[0]).suffix


def xpandas_read_csv(
    filepath_or_buffer, use_auth_token: Optional[Union[str, bool]] = None, **kwargs
):
    import pandas as pd

    if hasattr(filepath_or_buffer, "read"):
        return pd.read_csv(filepath_or_buffer, **kwargs)
    else:
        return pd.read_csv(
            xopen(filepath_or_buffer, use_auth_token=use_auth_token), **kwargs
        )


class StreamingDownloadManager(object):
    """
    Download manager that uses the "::" separator to navigate through
    (possibly remote) compressed archives.
    Contrary to the regular DownloadManager, the `download` and
    `extract` methods don't actually download nor extract
    data, but they rather return the path or url that could be opened
    using the `xopen` function which extends the
    builtin `open` function to stream data from remote files.
    """

    def __init__(
        self,
        dataset_name: Optional[str] = None,
        data_dir: Optional[str] = None,
        download_config: Optional[DownloadConfig] = None,
        base_path: Optional[str] = None,
    ):
        self._dataset_name = dataset_name
        self._data_dir = data_dir
        self._base_path = base_path or os.path.abspath(".")
        self.download_config = download_config or DownloadConfig()

    @property
    def manual_dir(self):
        return self._data_dir

    def download(self, url_or_urls):
        url_or_urls = map_nested(self._download, url_or_urls, map_tuple=True)
        return url_or_urls

    def _download(self, urlpath: str) -> str:
        urlpath = str(urlpath)
        if is_relative_path(urlpath):
            # append the relative path to the base_path
            urlpath = url_or_path_join(self._base_path, urlpath)
        return urlpath

    def extract(self, path_or_paths):
        urlpaths = map_nested(self._extract, path_or_paths, map_tuple=True)
        return urlpaths

    def _extract(self, urlpath: str) -> str:
        urlpath = str(urlpath)
        protocol = _get_extraction_protocol(
            urlpath, use_auth_token=self.download_config.use_auth_token
        )
        if protocol is None:
            # no extraction
            return urlpath
        elif protocol in SINGLE_FILE_COMPRESSION_PROTOCOLS:
            # there is one single file which is the uncompressed file
            inner_file = os.path.basename(urlpath.split("::")[0])
            inner_file = (
                inner_file[: inner_file.rindex(".")]
                if "." in inner_file
                else inner_file
            )
            # check for tar.gz, tar.bz2 etc.
            if inner_file.endswith(".tar"):
                return f"tar://::{protocol}://{inner_file}::{urlpath}"
            else:
                return f"{protocol}://{inner_file}::{urlpath}"
        else:
            return f"{protocol}://::{urlpath}"

    def download_and_extract(self, url_or_urls):
        return self.extract(self.download(url_or_urls))

    def iter_archive(self, urlpath: str):
        """Returns iterator over files within archive.

        Args:
            path: path to archive.

        Returns:
            Generator yielding tuple (path_within_archive, file_obj).
            File-Obj are opened in byte mode (io.BufferedReader)
        """
        with xopen(
            urlpath, "rb", use_auth_token=self.download_config.use_auth_token
        ) as f:
            stream = tarfile.open(fileobj=f, mode="r|*")
            for tarinfo in stream:
                file_path = tarinfo.name
                if not tarinfo.isreg():
                    continue
                if file_path is None:
                    continue
                if os.path.basename(file_path).startswith(".") or os.path.basename(
                    file_path
                ).startswith("__"):
                    # skipping hidden files
                    continue
                file_obj = stream.extractfile(tarinfo)
                yield (file_path, file_obj)
                stream.members = []
            del stream
