#
# Copyright (c) 2014 ThoughtWorks, Inc.
#
# Pixelated is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Pixelated 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with Pixelated. If not, see <http://www.gnu.org/licenses/>.

import io

import re
from twisted.protocols.basic import FileSender
from twisted.python.log import msg
from twisted.web import server
from twisted.web.resource import Resource
from twisted.internet import defer


class AttachmentResource(Resource):

    isLeaf = True

    def __init__(self, mail_service, attachment_id):
        Resource.__init__(self)
        self.attachment_id = attachment_id
        self.mail_service = mail_service

    def render_GET(self, request):
        def error_handler(failure):
            msg(failure, 'attachment not found')
            request.code = 404
            request.finish()
        encoding = request.args.get('encoding', [None])[0]
        filename = request.args.get('filename', [self.attachment_id])[0]
        request.setHeader(b'Content-Type', b'application/force-download')
        request.setHeader(b'Content-Disposition', bytes('attachment; filename=' + filename))

        d = self._send_attachment(encoding, filename, request)
        d.addErrback(error_handler)

        return server.NOT_DONE_YET

    @defer.inlineCallbacks
    def _send_attachment(self, encoding, filename, request):
        attachment = yield self.mail_service.attachment(self.attachment_id)

        bytes_io = io.BytesIO(attachment['content'])

        try:
            request.code = 200
            yield FileSender().beginFileTransfer(bytes_io, request)
        finally:
            bytes_io.close()
            request.finish()

    def _extract_mimetype(self, content_type):
        match = re.compile('([A-Za-z-]+\/[A-Za-z-]+)').search(content_type)
        return match.group(1)


class AttachmentsResource(Resource):

    def __init__(self, mail_service):
        Resource.__init__(self)
        self.mail_service = mail_service

    def getChild(self, attachment_id, request):
        return AttachmentResource(self.mail_service, attachment_id)