# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from synapse.http.server import respond_with_json, finish_request
from synapse.api.errors import (
    cs_error, Codes, SynapseError
)
from synapse.util import logcontext

from twisted.internet import defer
from twisted.protocols.basic import FileSender

from synapse.util.stringutils import is_ascii

import os

import logging
import urllib
import urlparse

logger = logging.getLogger(__name__)


def parse_media_id(request):
    try:
        # This allows users to append e.g. /test.png to the URL. Useful for
        # clients that parse the URL to see content type.
        server_name, media_id = request.postpath[:2]
        file_name = None
        if len(request.postpath) > 2:
            try:
                file_name = urlparse.unquote(request.postpath[-1]).decode("utf-8")
            except UnicodeDecodeError:
                pass
        return server_name, media_id, file_name
    except Exception:
        raise SynapseError(
            404,
            "Invalid media id token %r" % (request.postpath,),
            Codes.UNKNOWN,
        )


def respond_404(request):
    respond_with_json(
        request, 404,
        cs_error(
            "Not found %r" % (request.postpath,),
            code=Codes.NOT_FOUND,
        ),
        send_cors=True
    )


@defer.inlineCallbacks
def respond_with_file(request, media_type, file_path,
                      file_size=None, upload_name=None):
    logger.debug("Responding with %r", file_path)

    if os.path.isfile(file_path):
        request.setHeader(b"Content-Type", media_type.encode("UTF-8"))
        if upload_name:
            if is_ascii(upload_name):
                request.setHeader(
                    b"Content-Disposition",
                    b"inline; filename=%s" % (
                        urllib.quote(upload_name.encode("utf-8")),
                    ),
                )
            else:
                request.setHeader(
                    b"Content-Disposition",
                    b"inline; filename*=utf-8''%s" % (
                        urllib.quote(upload_name.encode("utf-8")),
                    ),
                )

        # cache for at least a day.
        # XXX: we might want to turn this off for data we don't want to
        # recommend caching as it's sensitive or private - or at least
        # select private. don't bother setting Expires as all our
        # clients are smart enough to be happy with Cache-Control
        request.setHeader(
            b"Cache-Control", b"public,max-age=86400,s-maxage=86400"
        )
        if file_size is None:
            stat = os.stat(file_path)
            file_size = stat.st_size

        request.setHeader(
            b"Content-Length", b"%d" % (file_size,)
        )

        with open(file_path, "rb") as f:
            yield logcontext.make_deferred_yieldable(
                FileSender().beginFileTransfer(f, request)
            )

        finish_request(request)
    else:
        respond_404(request)
