from io import BytesIO
from requests.adapters import BaseAdapter
from requests import PreparedRequest, Response, codes
from urllib.parse import urlparse, unquote
import errno
import os
import stat
import locale
import io


class FileAdapter(BaseAdapter):
    def __init__(self, set_content_length=True):
        super(FileAdapter, self).__init__()
        self._set_content_length = set_content_length

    def send(self, request: PreparedRequest, *args, **kwargs) -> Response:
        """Wraps a file, described in request, in a Response object.

        :param request: The PreparedRequest` being "sent".
        :returns: a Response object containing the file
        """

        # Check that the method makes sense. Only support GET
        if request.method not in ("GET", "HEAD"):
            raise ValueError("Invalid request method %s" % request.method)

        resp = Response()

        # Open the file, translate certain errors into HTTP responses
        # Use urllib's unquote to translate percent escapes into whatever
        # they actually need to be
        try:
            # Reject None URLs the same as a missing file
            if request.url is None:
                raise IOError(errno.ENOENT, os.strerror(errno.ENOENT), "None")

            # Parse the URL
            url_parts = urlparse(request.url)

            # Reject URLs with a hostname component
            if url_parts.netloc and url_parts.netloc != "localhost":
                raise ValueError("file: URLs with hostname components are not permitted")

            resp.request = request

            if request.url is not None:
                resp.url = request.url

            # Split the path on / (the URL directory separator) and decode any
            # % escapes in the parts
            path_parts = [unquote(p) for p in url_parts.path.split("/")]

            # Strip out the leading empty parts created from the leading /'s
            while path_parts and not path_parts[0]:
                path_parts.pop(0)

            # If os.sep is in any of the parts, someone fed us some shenanigans.
            # Treat is like a missing file.
            if any(os.sep in p for p in path_parts):
                raise IOError(errno.ENOENT, os.strerror(errno.ENOENT))

            # Look for a drive component. If one is present, store it separately
            # so that a directory separator can correctly be added to the real
            # path, and remove any empty path parts between the drive and the path.
            # Assume that a part ending with : or | (legacy) is a drive.
            if path_parts and (
                path_parts[0].endswith("|") or path_parts[0].endswith(":")
            ):
                path_drive = path_parts.pop(0)
                if path_drive.endswith("|"):
                    path_drive = path_drive[:-1] + ":"

                while path_parts and not path_parts[0]:
                    path_parts.pop(0)
            else:
                path_drive = ""

            # Try to put the path back together
            # Join the drive back in, and stick os.sep in front of the path to
            # make it absolute.
            path = path_drive + os.sep + os.path.join(*path_parts)

            # Check if the drive assumptions above were correct. If path_drive
            # is set, and os.path.splitdrive does not return a drive, it wasn't
            # really a drive. Put the path together again treating path_drive
            # as a normal path component.
            if path_drive and not os.path.splitdrive(path):
                path = os.sep + os.path.join(path_drive, *path_parts)

            # Use io.open since we need to add a release_conn method, and
            # methods can't be added to file objects in python 2.
            resp.raw = io.open(path, "rb")
            resp.raw.release_conn = resp.raw.close
        except IOError as e:
            if e.errno == errno.EACCES:
                resp.status_code = codes.forbidden
            elif e.errno == errno.ENOENT:
                resp.status_code = codes.not_found
            else:
                resp.status_code = codes.bad_request

            # Wrap the error message in a file-like object
            # The error message will be localized, try to convert the string
            # representation of the exception into a byte stream
            resp_str = str(e).encode(locale.getpreferredencoding(False))
            resp.raw = BytesIO(resp_str)
            resp.reason = str(e)
            if self._set_content_length:
                resp.headers["Content-Length"] = str(len(resp_str))

            # Add release_conn to the BytesIO object
            resp.raw.release_conn = resp.raw.close
        else:
            resp.status_code = codes.ok

            # If it's a regular file, set the Content-Length
            resp_stat = os.fstat(resp.raw.fileno())
            if stat.S_ISREG(resp_stat.st_mode) and self._set_content_length:
                resp.headers["Content-Length"] = str(resp_stat.st_size)

        return resp

    def close(self):
        pass
