#       Licensed to the Apache Software Foundation (ASF) under one
#       or more contributor license agreements.  See the NOTICE file
#       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 logging
from itertools import chain
from cPickle import dumps
from collections import OrderedDict

import bson

import tg
import jinja2
from paste.deploy.converters import asint
from tg import tmpl_context as c, app_globals as g

from ming.base import Object
from ming.orm import mapper, session, ThreadLocalORMSession

from allura.lib import utils
from allura.lib import helpers as h
from allura.model.repository import CommitDoc
from allura.model.repository import Commit, Tree, LastCommit, ModelCache
from allura.model.index import ArtifactReferenceDoc, ShortlinkDoc
from allura.model.auth import User
from allura.model.timeline import TransientActor

log = logging.getLogger(__name__)

QSIZE = 100


def refresh_repo(repo, all_commits=False, notify=True, new_clone=False, commits_are_new=None):
    if commits_are_new is None:
        commits_are_new = not all_commits and not new_clone

    all_commit_ids = commit_ids = list(repo.all_commit_ids())
    if not commit_ids:
        # the repo is empty, no need to continue
        return
    new_commit_ids = unknown_commit_ids(commit_ids)
    stats_log = h.log_action(log, 'commit')
    for ci in new_commit_ids:
        stats_log.info(
            '',
            meta=dict(
                module='scm-%s' % repo.repo_id,
                read='0'))
    if not all_commits:
        # Skip commits that are already in the DB
        commit_ids = new_commit_ids
    log.info('Refreshing %d commits on %s', len(commit_ids), repo.full_fs_path)

    # Refresh commits
    seen = set()
    for i, oid in enumerate(commit_ids):
        repo.refresh_commit_info(oid, seen, not all_commits)
        if (i + 1) % 100 == 0:
            log.info('Refresh commit info %d: %s', (i + 1), oid)

    refresh_commit_repos(all_commit_ids, repo)

    # Refresh child references
    for i, oid in enumerate(commit_ids):
        ci = CommitDoc.m.find(dict(_id=oid), validate=False).next()
        refresh_children(ci)
        if (i + 1) % 100 == 0:
            log.info('Refresh child info %d for parents of %s',
                     (i + 1), ci._id)

    # Clear any existing caches for branches/tags
    if repo.cached_branches:
        repo.cached_branches = []
        session(repo).flush()

    if repo.cached_tags:
        repo.cached_tags = []
        session(repo).flush()
    # The first view can be expensive to cache,
    # so we want to do it here instead of on the first view.
    repo.get_branches()
    repo.get_tags()

    if commits_are_new:
        for commit in commit_ids:
            new = repo.commit(commit)
            user = User.by_email_address(new.committed.email)
            if user is None:
                user = User.by_username(new.committed.name)
            if user is not None:
                g.statsUpdater.newCommit(new, repo.app_config.project, user)
            actor = user or TransientActor(
                    activity_name=new.committed.name or new.committed.email)
            g.director.create_activity(actor, 'committed', new,
                                       related_nodes=[repo.app_config.project],
                                       tags=['commit', repo.tool.lower()])

        from allura.webhooks import RepoPushWebhookSender
        by_branches, by_tags = _group_commits(repo, commit_ids)
        params = []
        for b, commits in by_branches.iteritems():
            ref = u'refs/heads/{}'.format(b) if b != '__default__' else None
            params.append(dict(commit_ids=commits, ref=ref))
        for t, commits in by_tags.iteritems():
            ref = u'refs/tags/{}'.format(t)
            params.append(dict(commit_ids=commits, ref=ref))
        if params:
            RepoPushWebhookSender().send(params)

    log.info('Refresh complete for %s', repo.full_fs_path)
    g.post_event('repo_refreshed', len(commit_ids), all_commits, new_clone)

    # Send notifications
    if notify:
        send_notifications(repo, reversed(commit_ids))


def refresh_commit_repos(all_commit_ids, repo):
    '''Refresh the list of repositories within which a set of commits are
    contained'''
    for oids in utils.chunked_iter(all_commit_ids, QSIZE):
        for ci in CommitDoc.m.find(dict(
                _id={'$in': list(oids)},
                repo_ids={'$ne': repo._id})):
            oid = ci._id
            ci.repo_ids.append(repo._id)
            index_id = 'allura.model.repository.Commit#' + oid
            ref = ArtifactReferenceDoc(dict(
                _id=index_id,
                artifact_reference=dict(
                    cls=bson.Binary(dumps(Commit)),
                    project_id=repo.app.config.project_id,
                    app_config_id=repo.app.config._id,
                    artifact_id=oid),
                references=[]))
            link0 = ShortlinkDoc(dict(
                _id=bson.ObjectId(),
                ref_id=index_id,
                project_id=repo.app.config.project_id,
                app_config_id=repo.app.config._id,
                link=repo.shorthand_for_commit(oid)[1:-1],
                url=repo.url_for_commit(oid)))
            # Always create a link for the full commit ID
            link1 = ShortlinkDoc(dict(
                _id=bson.ObjectId(),
                ref_id=index_id,
                project_id=repo.app.config.project_id,
                app_config_id=repo.app.config._id,
                link=oid,
                url=repo.url_for_commit(oid)))
            ci.m.save(safe=False, validate=False)
            ref.m.save(safe=False, validate=False)
            link0.m.save(safe=False, validate=False)
            link1.m.save(safe=False, validate=False)


def refresh_children(ci):
    '''Refresh the list of children of the given commit'''
    CommitDoc.m.update_partial(
        dict(_id={'$in': ci.parent_ids}),
        {'$addToSet': dict(child_ids=ci._id)},
        multi=True)


def unknown_commit_ids(all_commit_ids):
    '''filter out all commit ids that have already been cached'''
    result = []
    for chunk in utils.chunked_iter(all_commit_ids, QSIZE):
        chunk = list(chunk)
        q = CommitDoc.m.find(dict(_id={'$in': chunk}))
        known_commit_ids = set(ci._id for ci in q)
        result += [oid for oid in chunk if oid not in known_commit_ids]
    return result


def send_notifications(repo, commit_ids):
    """Create appropriate notification and feed objects for a refresh

    :param repo: A repository artifact instance.
    :type repo: Repository

    :param commit_ids: A list of commit hash strings, oldest to newest
    :type commit_ids: list
    """
    from allura.model import Feed, Notification
    commit_msgs = []
    base_url = tg.config['base_url']
    for oids in utils.chunked_iter(commit_ids, QSIZE):
        chunk = list(oids)
        index = dict(
            (doc._id, doc)
            for doc in Commit.query.find(dict(_id={'$in': chunk})))
        for oid in chunk:
            ci = index[oid]
            href = repo.url_for_commit(oid)
            title = _title(ci.message)
            summary = _summarize(ci.message)
            Feed.post(
                repo, title=title,
                description='%s<br><a href="%s">View Changes</a>' % (
                    summary, href),
                author_link=ci.author_url,
                author_name=ci.authored.name,
                link=href,
                unique_id=href)

            summary = g.markdown_commit.convert(ci.message.strip()) if ci.message else ""
            current_branch = repo.symbolics_for_commit(ci)[0]  # only the head of a branch will have this
            commit_msgs.append(dict(
                author=ci.authored.name,
                date=ci.authored.date.strftime("%m/%d/%Y %H:%M"),
                summary=summary,
                branches=current_branch,
                commit_url=base_url + href,
                shorthand_id=ci.shorthand_id()))

    # fill out the branch info for all the other commits
    prev_branch = None
    for c_msg in reversed(commit_msgs):
        if not c_msg['branches']:
            c_msg['branches'] = prev_branch
        prev_branch = c_msg['branches']

    # mark which ones are first on a branch and need the branch name shown
    last_branch = None
    for c_msg in commit_msgs:
        if c_msg['branches'] != last_branch:
            c_msg['show_branch_name'] = True
        last_branch = c_msg['branches']

    if commit_msgs:
        if len(commit_msgs) > 1:
            subject = u"{} new commits to {}".format(len(commit_msgs), repo.app.config.options.mount_label)
        else:
            commit = commit_msgs[0]
            subject = u'New commit {} by {}'.format(commit['shorthand_id'], commit['author'])
        text = g.jinja2_env.get_template("allura:templates/mail/commits.md").render(
            commit_msgs=commit_msgs,
            max_num_commits=asint(tg.config.get('scm.notify.max_commits', 100)),
        )

        Notification.post(
            artifact=repo,
            topic='metadata',
            subject=subject,
            text=text)


def _title(message):
    if not message:
        return ''
    line = message.splitlines()[0]
    return jinja2.filters.do_truncate(None, line, 200, killwords=True, leeway=3)


def _summarize(message):
    if not message:
        return ''
    summary = []
    for line in message.splitlines():
        line = line.rstrip()
        if line:
            summary.append(line)
        else:
            break
    return ' '.join(summary)


def last_known_commit_id(all_commit_ids, new_commit_ids):
    """
    Return the newest "known" (cached in mongo) commit id.

    Params:
        all_commit_ids: Every commit id from the repo on disk, sorted oldest to
                        newest.
        new_commit_ids: Commit ids that are not yet cached in mongo, sorted
                        oldest to newest.
    """
    if not all_commit_ids:
        return None
    if not new_commit_ids:
        return all_commit_ids[-1]
    return all_commit_ids[all_commit_ids.index(new_commit_ids[0]) - 1]


def _group_commits(repo, commit_ids):
    by_branches = {}
    by_tags = {}
    # svn has no branches, so we need __default__ as a fallback to collect
    # all commits into
    current_branches = ['__default__']
    current_tags = []
    for commit in commit_ids:
        ci = repo.commit(commit)
        branches, tags = repo.symbolics_for_commit(ci)
        if branches:
            current_branches = branches
        if tags:
            current_tags = tags
        for b in current_branches:
            if b not in by_branches.keys():
                by_branches[b] = []
            by_branches[b].append(commit)
        for t in current_tags:
            if t not in by_tags.keys():
                by_tags[t] = []
            by_tags[t].append(commit)
    return by_branches, by_tags