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#       distributed with this work for additional information
#       regarding copyright ownership.  The ASF licenses this file
#       to you 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.

import re
import logging
from itertools import groupby
from cPickle import dumps, loads
from collections import defaultdict
from urllib import unquote

import bson
import pymongo
from pylons import tmpl_context as c

from ming import collection, Field, Index
from ming import schema as S
from ming.utils import LazyProperty
from ming.orm import session, mapper
from ming.orm import ForeignIdProperty, RelationProperty

from allura.lib import helpers as h

from .session import main_doc_session, main_orm_session
from .project import Project

log = logging.getLogger(__name__)

# Collection definitions
ArtifactReferenceDoc = collection(
    'artifact_reference', main_doc_session,
    Field('_id', str),
    Field('artifact_reference', dict(
        cls=S.Binary(),
        project_id=S.ObjectId(),
        app_config_id=S.ObjectId(),
        artifact_id=S.Anything(if_missing=None))),
    Field('references', [str], index=True),
    Index('artifact_reference.project_id'),  # used in ReindexCommand
)

ShortlinkDoc = collection(
    'shortlink', main_doc_session,
    Field('_id', S.ObjectId()),
    # index needed for from_artifact() and index_tasks.py:del_artifacts
    Field('ref_id', str, index=True),
    Field('project_id', S.ObjectId()),
    Field('app_config_id', S.ObjectId()),
    Field('link', str),
    Field('url', str),
    # used by from_links()  More helpful to have project_id first, for other
    # queries
    Index('project_id', 'link'),
)

# Class definitions


class ArtifactReference(object):

    @classmethod
    def from_artifact(cls, artifact):
        '''Upsert logic to generate an ArtifactReference object from an artifact'''
        obj = cls.query.get(_id=artifact.index_id())
        if obj is not None:
            return obj
        try:
            obj = cls(
                _id=artifact.index_id(),
                artifact_reference=dict(
                    cls=bson.Binary(dumps(artifact.__class__)),
                    project_id=artifact.app_config.project_id,
                    app_config_id=artifact.app_config._id,
                    artifact_id=artifact._id))
            session(obj).flush(obj)
            return obj
        except pymongo.errors.DuplicateKeyError:  # pragma no cover
            session(obj).expunge(obj)
            return cls.query.get(_id=artifact.index_id())

    @LazyProperty
    def artifact(self):
        '''Look up the artifact referenced'''
        aref = self.artifact_reference
        try:
            cls = loads(str(aref.cls))
            with h.push_context(aref.project_id):
                return cls.query.get(_id=aref.artifact_id)
        except:
            log.exception('Error loading artifact for %s: %r',
                          self._id, aref)


class Shortlink(object):

    '''Collection mapping shorthand_ids for artifacts to ArtifactReferences'''

    # Regexes used to find shortlinks
    _core_re = r'''(\[
            (?:(?P<project_id>.*?):)?      # optional project ID
            (?:(?P<app_id>.*?):)?      # optional tool ID
            (?P<artifact_id>.*)             # artifact ID
    \])'''
    re_link_1 = re.compile(r'\s' + _core_re, re.VERBOSE)
    re_link_2 = re.compile(r'^' + _core_re, re.VERBOSE)

    def __repr__(self):
        return '<Shortlink %s %s %s -> %s>' % (
            self.project_id,
            self.app_config_id,
            self.link,
            self.ref_id)

    @classmethod
    def lookup(cls, link):
        return cls.from_links(link)[link]

    @classmethod
    def from_artifact(cls, a):
        result = cls.query.get(ref_id=a.index_id())
        if result is None:
            try:
                result = cls(
                    ref_id=a.index_id(),
                    project_id=a.app_config.project_id,
                    app_config_id=a.app_config._id)
                session(result).flush(result)
            except pymongo.errors.DuplicateKeyError:  # pragma no cover
                session(result).expunge(result)
                result = cls.query.get(ref_id=a.index_id())
        result.link = a.shorthand_id()
        result.url = a.url()
        if result.link is None:
            result.delete()
            return None
        return result

    @classmethod
    def from_links(cls, *links):
        '''Convert a sequence of shortlinks to the matching Shortlink objects'''
        if len(links):
            result = {}
            # Parse all the links
            parsed_links = dict((link, cls._parse_link(link))
                                for link in links)
            links_by_artifact = defaultdict(list)
            project_ids = set()
            for link, d in parsed_links.items():
                if d:
                    project_ids.add(d['project_id'])
                    links_by_artifact[unquote(d['artifact'])].append(d)
                else:
                    result[link] = parsed_links.pop(link)
            q = cls.query.find(dict(
                link={'$in': links_by_artifact.keys()},
                project_id={'$in': list(project_ids)}
            ), validate=False)
            matches_by_artifact = dict(
                (link, list(matches))
                for link, matches in groupby(q, key=lambda s: unquote(s.link)))
            for link, d in parsed_links.iteritems():
                matches = matches_by_artifact.get(unquote(d['artifact']), [])
                matches = (
                    m for m in matches
                    if m.project.shortname == d['project'] and
                    m.project.neighborhood_id == d['nbhd'] and
                    m.app_config is not None and
                    m.project.app_instance(m.app_config.options.mount_point))
                if d['app']:
                    matches = (
                        m for m in matches
                        if m.app_config.options.mount_point == d['app'])
                matches = list(matches)
                if matches:
                    result[link] = matches[0]
                else:
                    result[link] = None
                if len(matches) > 1:
                    log.warn('Ambiguous link to %s', link)
                    for m in matches:
                        log.warn('... %r', m)
            return result
        else:
            return {}

    @classmethod
    def _parse_link(cls, s):
        '''Parse a shortlink into its nbhd/project/app/artifact parts'''
        s = s.strip()
        if s.startswith('['):
            s = s[1:]
        if s.endswith(']'):
            s = s[:-1]
        parts = s.split(':')
        p_shortname = None
        p_id = None
        p_nbhd = None
        if getattr(c, 'project', None):
            p_shortname = getattr(c.project, 'shortname', None)
            p_id = getattr(c.project, '_id', None)
            p_nbhd = c.project.neighborhood_id
        if len(parts) == 3:
            p = Project.query.get(shortname=parts[0], neighborhood_id=p_nbhd)
            if p:
                p_id = p._id
            return dict(
                nbhd=p_nbhd,
                project=parts[0],
                project_id=p_id,
                app=parts[1],
                artifact=parts[2])
        elif len(parts) == 2:
            return dict(
                nbhd=p_nbhd,
                project=p_shortname,
                project_id=p_id,
                app=parts[0],
                artifact=parts[1])
        elif len(parts) == 1:
            return dict(
                nbhd=p_nbhd,
                project=p_shortname,
                project_id=p_id,
                app=None,
                artifact=parts[0])
        else:
            return None

# Mapper definitions
mapper(ArtifactReference, ArtifactReferenceDoc, main_orm_session)
mapper(Shortlink, ShortlinkDoc, main_orm_session, properties=dict(
    ref_id=ForeignIdProperty(ArtifactReference),
    project_id=ForeignIdProperty('Project'),
    app_config_id=ForeignIdProperty('AppConfig'),
    project=RelationProperty('Project'),
    app_config=RelationProperty('AppConfig'),
    ref=RelationProperty(ArtifactReference)))