# Copyright (C) 2012-2014  Codethink Limited
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.


import cliapp
import logging
import urllib
import urllib2
import urlparse


class HeadRequest(urllib2.Request):  # pragma: no cover

    def get_method(self):
        return 'HEAD'


class GetError(cliapp.AppException):

    def __init__(self, cache, artifact):
        cliapp.AppException.__init__(
            self, 'Failed to get the artifact %s '
                  'from the artifact cache %s' %
                  (artifact.basename(), cache))


class GetArtifactMetadataError(GetError):

    def __init__(self, cache, artifact, name):
        cliapp.AppException.__init__(
            self, 'Failed to get metadata %s for the artifact %s '
                  'from the artifact cache %s' %
                  (name, artifact.basename(), cache))


class GetSourceMetadataError(GetError):

    def __init__(self, cache, source, cache_key, name):
        cliapp.AppException.__init__(
            self, 'Failed to get metadata %s for source %s '
                  'and cache key %s from the artifact cache %s' %
                  (name, source, cache_key, cache))


class RemoteArtifactCache(object):

    def __init__(self, server_url):
        self.server_url = server_url

    def has(self, artifact):
        return self._has_file(artifact.basename())

    def has_artifact_metadata(self, artifact, name):
        return self._has_file(artifact.metadata_basename(name))

    def has_source_metadata(self, source, cachekey, name):
        filename = '%s.%s' % (cachekey, name)
        return self._has_file(filename)

    def get(self, artifact, log=logging.error):
        try:
            return self._get_file(artifact.basename())
        except urllib2.URLError, e:
            log(str(e))
            raise GetError(self, artifact)

    def get_artifact_metadata(self, artifact, name, log=logging.error):
        try:
            return self._get_file(artifact.metadata_basename(name))
        except urllib2.URLError, e:
            log(str(e))
            raise GetArtifactMetadataError(self, artifact, name)

    def get_source_metadata(self, source, cachekey, name):
        filename = '%s.%s' % (cachekey, name)
        try:
            return self._get_file(filename)
        except urllib2.URLError:
            raise GetSourceMetadataError(self, source, cachekey, name)

    def _has_file(self, filename):  # pragma: no cover
        url = self._request_url(filename)
        logging.debug('RemoteArtifactCache._has_file: url=%s' % url)
        request = HeadRequest(url)
        try:
            urllib2.urlopen(request)
            return True
        except (urllib2.HTTPError, urllib2.URLError):
            return False

    def _get_file(self, filename):  # pragma: no cover
        url = self._request_url(filename)
        logging.debug('RemoteArtifactCache._get_file: url=%s' % url)
        return urllib2.urlopen(url)

    def _request_url(self, filename):  # pragma: no cover
        server_url = self.server_url
        if not server_url.endswith('/'):
            server_url += '/'
        return urlparse.urljoin(
            server_url, '/1.0/artifacts?filename=%s' % 
            urllib.quote(filename))

    def __str__(self):  # pragma: no cover
        return self.server_url