rhodecode/controllers/pullrequests.py

# -*- coding: utf-8 -*-

# Copyright (C) 2012-2017 RhodeCode GmbH
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License, version 3
# (only), as published by the Free Software Foundation.
#
# 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 Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# This program is dual-licensed. If you wish to learn more about the
# RhodeCode Enterprise Edition, including its added features, Support services,
# and proprietary license terms, please see https://rhodecode.com/licenses/

"""
pull requests controller for rhodecode for initializing pull requests
"""
import types

import peppercorn
import formencode
import logging
import collections

from webob.exc import HTTPNotFound, HTTPForbidden, HTTPBadRequest
from pylons import request, tmpl_context as c, url
from pylons.controllers.util import redirect
from pylons.i18n.translation import _
from pyramid.threadlocal import get_current_registry
from sqlalchemy.sql import func
from sqlalchemy.sql.expression import or_

from rhodecode import events
from rhodecode.lib import auth, diffs, helpers as h, codeblocks
from rhodecode.lib.ext_json import json
from rhodecode.lib.base import (
    BaseRepoController, render, vcs_operation_context)
from rhodecode.lib.auth import (
    LoginRequired, HasRepoPermissionAnyDecorator, NotAnonymous,
    HasAcceptedRepoType, XHRRequired)
from rhodecode.lib.channelstream import channelstream_request
from rhodecode.lib.utils import jsonify
from rhodecode.lib.utils2 import (
    safe_int, safe_str, str2bool, safe_unicode)
from rhodecode.lib.vcs.backends.base import (
    EmptyCommit, UpdateFailureReason, EmptyRepository)
from rhodecode.lib.vcs.exceptions import (
    EmptyRepositoryError, CommitDoesNotExistError, RepositoryRequirementError,
    NodeDoesNotExistError)

from rhodecode.model.changeset_status import ChangesetStatusModel
from rhodecode.model.comment import CommentsModel
from rhodecode.model.db import (PullRequest, ChangesetStatus, ChangesetComment,
    Repository, PullRequestVersion)
from rhodecode.model.forms import PullRequestForm
from rhodecode.model.meta import Session
from rhodecode.model.pull_request import PullRequestModel, MergeCheck

log = logging.getLogger(__name__)


class PullrequestsController(BaseRepoController):
    def __before__(self):
        super(PullrequestsController, self).__before__()

    def _load_compare_data(self, pull_request, inline_comments):
        """
        Load context data needed for generating compare diff

        :param pull_request: object related to the request
        :param enable_comments: flag to determine if comments are included
        """
        source_repo = pull_request.source_repo
        source_ref_id = pull_request.source_ref_parts.commit_id

        target_repo = pull_request.target_repo
        target_ref_id = pull_request.target_ref_parts.commit_id

        # despite opening commits for bookmarks/branches/tags, we always
        # convert this to rev to prevent changes after bookmark or branch change
        c.source_ref_type = 'rev'
        c.source_ref = source_ref_id

        c.target_ref_type = 'rev'
        c.target_ref = target_ref_id

        c.source_repo = source_repo
        c.target_repo = target_repo

        c.fulldiff = bool(request.GET.get('fulldiff'))

        # diff_limit is the old behavior, will cut off the whole diff
        # if the limit is applied  otherwise will just hide the
        # big files from the front-end
        diff_limit = self.cut_off_limit_diff
        file_limit = self.cut_off_limit_file

        pre_load = ["author", "branch", "date", "message"]

        c.commit_ranges = []
        source_commit = EmptyCommit()
        target_commit = EmptyCommit()
        c.missing_requirements = False
        try:
            c.commit_ranges = [
                source_repo.get_commit(commit_id=rev, pre_load=pre_load)
                for rev in pull_request.revisions]

            c.statuses = source_repo.statuses(
                [x.raw_id for x in c.commit_ranges])

            target_commit = source_repo.get_commit(
                commit_id=safe_str(target_ref_id))
            source_commit = source_repo.get_commit(
                commit_id=safe_str(source_ref_id))
        except RepositoryRequirementError:
            c.missing_requirements = True

        # auto collapse if we have more than limit
        collapse_limit = diffs.DiffProcessor._collapse_commits_over
        c.collapse_all_commits = len(c.commit_ranges) > collapse_limit

        c.changes = {}
        c.missing_commits = False
        if (c.missing_requirements or
                isinstance(source_commit, EmptyCommit) or
                    source_commit == target_commit):
            _parsed = []
            c.missing_commits = True
        else:
            vcs_diff = PullRequestModel().get_diff(pull_request)
            diff_processor = diffs.DiffProcessor(
                vcs_diff, format='newdiff', diff_limit=diff_limit,
                file_limit=file_limit, show_full_diff=c.fulldiff)

            _parsed = diff_processor.prepare()
            c.limited_diff = isinstance(_parsed, diffs.LimitedDiffContainer)

            included_files = {}
            for f in _parsed:
                included_files[f['filename']] = f['stats']

            c.deleted_files = [fname for fname in inline_comments if
                               fname not in included_files]

            c.deleted_files_comments = collections.defaultdict(dict)
            for fname, per_line_comments in inline_comments.items():
                if fname in c.deleted_files:
                    c.deleted_files_comments[fname]['stats'] = 0
                    c.deleted_files_comments[fname]['comments'] = list()
                    for lno, comments in per_line_comments.items():
                        c.deleted_files_comments[fname]['comments'].extend(comments)

            def _node_getter(commit):
                def get_node(fname):
                    try:
                        return commit.get_node(fname)
                    except NodeDoesNotExistError:
                        return None
                return get_node

            c.diffset = codeblocks.DiffSet(
                repo_name=c.repo_name,
                source_repo_name=c.source_repo.repo_name,
                source_node_getter=_node_getter(target_commit),
                target_node_getter=_node_getter(source_commit),
                comments=inline_comments
            ).render_patchset(_parsed, target_commit.raw_id, source_commit.raw_id)

    def _extract_ordering(self, request):
        column_index = safe_int(request.GET.get('order[0][column]'))
        order_dir = request.GET.get('order[0][dir]', 'desc')
        order_by = request.GET.get(
            'columns[%s][data][sort]' % column_index, 'name_raw')
        return order_by, order_dir

    @LoginRequired()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    @HasAcceptedRepoType('git', 'hg')
    def show_all(self, repo_name):
        # filter types
        c.active = 'open'
        c.source = str2bool(request.GET.get('source'))
        c.closed = str2bool(request.GET.get('closed'))
        c.my = str2bool(request.GET.get('my'))
        c.awaiting_review = str2bool(request.GET.get('awaiting_review'))
        c.awaiting_my_review = str2bool(request.GET.get('awaiting_my_review'))
        c.repo_name = repo_name

        opened_by = None
        if c.my:
            c.active = 'my'
            opened_by = [c.rhodecode_user.user_id]

        statuses = [PullRequest.STATUS_NEW, PullRequest.STATUS_OPEN]
        if c.closed:
            c.active = 'closed'
            statuses = [PullRequest.STATUS_CLOSED]

        if c.awaiting_review and not c.source:
            c.active = 'awaiting'
        if c.source and not c.awaiting_review:
            c.active = 'source'
        if c.awaiting_my_review:
            c.active = 'awaiting_my'

        data = self._get_pull_requests_list(
            repo_name=repo_name, opened_by=opened_by, statuses=statuses)
        if not request.is_xhr:
            c.data = json.dumps(data['data'])
            c.records_total = data['recordsTotal']
            return render('/pullrequests/pullrequests.mako')
        else:
            return json.dumps(data)

    def _get_pull_requests_list(self, repo_name, opened_by, statuses):
        # pagination
        start = safe_int(request.GET.get('start'), 0)
        length = safe_int(request.GET.get('length'), c.visual.dashboard_items)
        order_by, order_dir = self._extract_ordering(request)

        if c.awaiting_review:
            pull_requests = PullRequestModel().get_awaiting_review(
                repo_name, source=c.source, opened_by=opened_by,
                statuses=statuses, offset=start, length=length,
                order_by=order_by, order_dir=order_dir)
            pull_requests_total_count = PullRequestModel(
            ).count_awaiting_review(
                repo_name, source=c.source, statuses=statuses,
                opened_by=opened_by)
        elif c.awaiting_my_review:
            pull_requests = PullRequestModel().get_awaiting_my_review(
                repo_name, source=c.source, opened_by=opened_by,
                user_id=c.rhodecode_user.user_id, statuses=statuses,
                offset=start, length=length, order_by=order_by,
                order_dir=order_dir)
            pull_requests_total_count = PullRequestModel(
            ).count_awaiting_my_review(
                repo_name, source=c.source, user_id=c.rhodecode_user.user_id,
                statuses=statuses, opened_by=opened_by)
        else:
            pull_requests = PullRequestModel().get_all(
                repo_name, source=c.source, opened_by=opened_by,
                statuses=statuses, offset=start, length=length,
                order_by=order_by, order_dir=order_dir)
            pull_requests_total_count = PullRequestModel().count_all(
                repo_name, source=c.source, statuses=statuses,
                opened_by=opened_by)

        from rhodecode.lib.utils import PartialRenderer
        _render = PartialRenderer('data_table/_dt_elements.mako')
        data = []
        for pr in pull_requests:
            comments = CommentsModel().get_all_comments(
                c.rhodecode_db_repo.repo_id, pull_request=pr)

            data.append({
                'name': _render('pullrequest_name',
                                pr.pull_request_id, pr.target_repo.repo_name),
                'name_raw': pr.pull_request_id,
                'status': _render('pullrequest_status',
                                  pr.calculated_review_status()),
                'title': _render(
                    'pullrequest_title', pr.title, pr.description),
                'description': h.escape(pr.description),
                'updated_on': _render('pullrequest_updated_on',
                                      h.datetime_to_time(pr.updated_on)),
                'updated_on_raw': h.datetime_to_time(pr.updated_on),
                'created_on': _render('pullrequest_updated_on',
                                      h.datetime_to_time(pr.created_on)),
                'created_on_raw': h.datetime_to_time(pr.created_on),
                'author': _render('pullrequest_author',
                                  pr.author.full_contact, ),
                'author_raw': pr.author.full_name,
                'comments': _render('pullrequest_comments', len(comments)),
                'comments_raw': len(comments),
                'closed': pr.is_closed(),
            })
        # json used to render the grid
        data = ({
            'data': data,
            'recordsTotal': pull_requests_total_count,
            'recordsFiltered': pull_requests_total_count,
        })
        return data

    @LoginRequired()
    @NotAnonymous()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    @HasAcceptedRepoType('git', 'hg')
    def index(self):
        source_repo = c.rhodecode_db_repo

        try:
            source_repo.scm_instance().get_commit()
        except EmptyRepositoryError:
            h.flash(h.literal(_('There are no commits yet')),
                    category='warning')
            redirect(url('summary_home', repo_name=source_repo.repo_name))

        commit_id = request.GET.get('commit')
        branch_ref = request.GET.get('branch')
        bookmark_ref = request.GET.get('bookmark')

        try:
            source_repo_data = PullRequestModel().generate_repo_data(
                source_repo, commit_id=commit_id,
                branch=branch_ref, bookmark=bookmark_ref)
        except CommitDoesNotExistError as e:
            log.exception(e)
            h.flash(_('Commit does not exist'), 'error')
            redirect(url('pullrequest_home', repo_name=source_repo.repo_name))

        default_target_repo = source_repo

        if source_repo.parent:
            parent_vcs_obj = source_repo.parent.scm_instance()
            if parent_vcs_obj and not parent_vcs_obj.is_empty():
                # change default if we have a parent repo
                default_target_repo = source_repo.parent

        target_repo_data = PullRequestModel().generate_repo_data(
            default_target_repo)

        selected_source_ref = source_repo_data['refs']['selected_ref']

        title_source_ref = selected_source_ref.split(':', 2)[1]
        c.default_title = PullRequestModel().generate_pullrequest_title(
            source=source_repo.repo_name,
            source_ref=title_source_ref,
            target=default_target_repo.repo_name
        )

        c.default_repo_data = {
            'source_repo_name': source_repo.repo_name,
            'source_refs_json': json.dumps(source_repo_data),
            'target_repo_name': default_target_repo.repo_name,
            'target_refs_json': json.dumps(target_repo_data),
        }
        c.default_source_ref = selected_source_ref

        return render('/pullrequests/pullrequest.mako')

    @LoginRequired()
    @NotAnonymous()
    @XHRRequired()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    @jsonify
    def get_repo_refs(self, repo_name, target_repo_name):
        repo = Repository.get_by_repo_name(target_repo_name)
        if not repo:
            raise HTTPNotFound
        return PullRequestModel().generate_repo_data(repo)

    @LoginRequired()
    @NotAnonymous()
    @XHRRequired()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    @jsonify
    def get_repo_destinations(self, repo_name):
        repo = Repository.get_by_repo_name(repo_name)
        if not repo:
            raise HTTPNotFound
        filter_query = request.GET.get('query')

        query = Repository.query() \
            .order_by(func.length(Repository.repo_name)) \
            .filter(or_(
            Repository.repo_name == repo.repo_name,
            Repository.fork_id == repo.repo_id))

        if filter_query:
            ilike_expression = u'%{}%'.format(safe_unicode(filter_query))
            query = query.filter(
                Repository.repo_name.ilike(ilike_expression))

        add_parent = False
        if repo.parent:
            if filter_query in repo.parent.repo_name:
                parent_vcs_obj = repo.parent.scm_instance()
                if parent_vcs_obj and not parent_vcs_obj.is_empty():
                    add_parent = True

        limit = 20 - 1 if add_parent else 20
        all_repos = query.limit(limit).all()
        if add_parent:
            all_repos += [repo.parent]

        repos = []
        for obj in self.scm_model.get_repos(all_repos):
            repos.append({
                'id': obj['name'],
                'text': obj['name'],
                'type': 'repo',
                'obj': obj['dbrepo']
            })

        data = {
            'more': False,
            'results': [{
                'text': _('Repositories'),
                'children': repos
            }] if repos else []
        }
        return data

    @LoginRequired()
    @NotAnonymous()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    @HasAcceptedRepoType('git', 'hg')
    @auth.CSRFRequired()
    def create(self, repo_name):
        repo = Repository.get_by_repo_name(repo_name)
        if not repo:
            raise HTTPNotFound

        controls = peppercorn.parse(request.POST.items())

        try:
            _form = PullRequestForm(repo.repo_id)().to_python(controls)
        except formencode.Invalid as errors:
            if errors.error_dict.get('revisions'):
                msg = 'Revisions: %s' % errors.error_dict['revisions']
            elif errors.error_dict.get('pullrequest_title'):
                msg = _('Pull request requires a title with min. 3 chars')
            else:
                msg = _('Error creating pull request: {}').format(errors)
            log.exception(msg)
            h.flash(msg, 'error')

            # would rather just go back to form ...
            return redirect(url('pullrequest_home', repo_name=repo_name))

        source_repo = _form['source_repo']
        source_ref = _form['source_ref']
        target_repo = _form['target_repo']
        target_ref = _form['target_ref']
        commit_ids = _form['revisions'][::-1]
        reviewers = [
            (r['user_id'], r['reasons']) for r in _form['review_members']]

        # find the ancestor for this pr
        source_db_repo = Repository.get_by_repo_name(_form['source_repo'])
        target_db_repo = Repository.get_by_repo_name(_form['target_repo'])

        source_scm = source_db_repo.scm_instance()
        target_scm = target_db_repo.scm_instance()

        source_commit = source_scm.get_commit(source_ref.split(':')[-1])
        target_commit = target_scm.get_commit(target_ref.split(':')[-1])

        ancestor = source_scm.get_common_ancestor(
            source_commit.raw_id, target_commit.raw_id, target_scm)

        target_ref_type, target_ref_name, __ = _form['target_ref'].split(':')
        target_ref = ':'.join((target_ref_type, target_ref_name, ancestor))

        pullrequest_title = _form['pullrequest_title']
        title_source_ref = source_ref.split(':', 2)[1]
        if not pullrequest_title:
            pullrequest_title = PullRequestModel().generate_pullrequest_title(
                source=source_repo,
                source_ref=title_source_ref,
                target=target_repo
            )

        description = _form['pullrequest_desc']
        try:
            pull_request = PullRequestModel().create(
                c.rhodecode_user.user_id, source_repo, source_ref, target_repo,
                target_ref, commit_ids, reviewers, pullrequest_title,
                description
            )
            Session().commit()
            h.flash(_('Successfully opened new pull request'),
                    category='success')
        except Exception as e:
            msg = _('Error occurred during sending pull request')
            log.exception(msg)
            h.flash(msg, category='error')
            return redirect(url('pullrequest_home', repo_name=repo_name))

        return redirect(url('pullrequest_show', repo_name=target_repo,
                            pull_request_id=pull_request.pull_request_id))

    @LoginRequired()
    @NotAnonymous()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    @auth.CSRFRequired()
    @jsonify
    def update(self, repo_name, pull_request_id):
        pull_request_id = safe_int(pull_request_id)
        pull_request = PullRequest.get_or_404(pull_request_id)
        # only owner or admin can update it
        allowed_to_update = PullRequestModel().check_user_update(
            pull_request, c.rhodecode_user)
        if allowed_to_update:
            controls = peppercorn.parse(request.POST.items())

            if 'review_members' in controls:
                self._update_reviewers(
                    pull_request_id, controls['review_members'])
            elif str2bool(request.POST.get('update_commits', 'false')):
                self._update_commits(pull_request)
            elif str2bool(request.POST.get('close_pull_request', 'false')):
                self._reject_close(pull_request)
            elif str2bool(request.POST.get('edit_pull_request', 'false')):
                self._edit_pull_request(pull_request)
            else:
                raise HTTPBadRequest()
            return True
        raise HTTPForbidden()

    def _edit_pull_request(self, pull_request):
        try:
            PullRequestModel().edit(
                pull_request, request.POST.get('title'),
                request.POST.get('description'))
        except ValueError:
            msg = _(u'Cannot update closed pull requests.')
            h.flash(msg, category='error')
            return
        else:
            Session().commit()

        msg = _(u'Pull request title & description updated.')
        h.flash(msg, category='success')
        return

    def _update_commits(self, pull_request):
        resp = PullRequestModel().update_commits(pull_request)

        if resp.executed:
            msg = _(
                u'Pull request updated to "{source_commit_id}" with '
                u'{count_added} added, {count_removed} removed commits.')
            msg = msg.format(
                source_commit_id=pull_request.source_ref_parts.commit_id,
                count_added=len(resp.changes.added),
                count_removed=len(resp.changes.removed))
            h.flash(msg, category='success')

            registry = get_current_registry()
            rhodecode_plugins = getattr(registry, 'rhodecode_plugins', {})
            channelstream_config = rhodecode_plugins.get('channelstream', {})
            if channelstream_config.get('enabled'):
                message = msg + (
                    ' - <a onclick="window.location.reload()">'
                    '<strong>{}</strong></a>'.format(_('Reload page')))
                channel = '/repo${}$/pr/{}'.format(
                    pull_request.target_repo.repo_name,
                    pull_request.pull_request_id
                )
                payload = {
                    'type': 'message',
                    'user': 'system',
                    'exclude_users': [request.user.username],
                    'channel': channel,
                    'message': {
                        'message': message,
                        'level': 'success',
                        'topic': '/notifications'
                    }
                }
                channelstream_request(
                    channelstream_config, [payload], '/message',
                    raise_exc=False)
        else:
            msg = PullRequestModel.UPDATE_STATUS_MESSAGES[resp.reason]
            warning_reasons = [
                UpdateFailureReason.NO_CHANGE,
                UpdateFailureReason.WRONG_REF_TPYE,
            ]
            category = 'warning' if resp.reason in warning_reasons else 'error'
            h.flash(msg, category=category)

    @auth.CSRFRequired()
    @LoginRequired()
    @NotAnonymous()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    def merge(self, repo_name, pull_request_id):
        """
        POST /{repo_name}/pull-request/{pull_request_id}

        Merge will perform a server-side merge of the specified
        pull request, if the pull request is approved and mergeable.
        After successful merging, the pull request is automatically
        closed, with a relevant comment.
        """
        pull_request_id = safe_int(pull_request_id)
        pull_request = PullRequest.get_or_404(pull_request_id)
        user = c.rhodecode_user

        check = MergeCheck.validate(pull_request, user)
        merge_possible = not check.failed

        for err_type, error_msg in check.errors:
            h.flash(error_msg, category=err_type)

        if merge_possible:
            log.debug("Pre-conditions checked, trying to merge.")
            extras = vcs_operation_context(
                request.environ, repo_name=pull_request.target_repo.repo_name,
                username=user.username, action='push',
                scm=pull_request.target_repo.repo_type)
            self._merge_pull_request(pull_request, user, extras)

        return redirect(url(
            'pullrequest_show',
            repo_name=pull_request.target_repo.repo_name,
            pull_request_id=pull_request.pull_request_id))

    def _merge_pull_request(self, pull_request, user, extras):
        merge_resp = PullRequestModel().merge(
            pull_request, user, extras=extras)

        if merge_resp.executed:
            log.debug("The merge was successful, closing the pull request.")
            PullRequestModel().close_pull_request(
                pull_request.pull_request_id, user)
            Session().commit()
            msg = _('Pull request was successfully merged and closed.')
            h.flash(msg, category='success')
        else:
            log.debug(
                "The merge was not successful. Merge response: %s",
                merge_resp)
            msg = PullRequestModel().merge_status_message(
                merge_resp.failure_reason)
            h.flash(msg, category='error')

    def _update_reviewers(self, pull_request_id, review_members):
        reviewers = [
            (int(r['user_id']), r['reasons']) for r in review_members]
        PullRequestModel().update_reviewers(pull_request_id, reviewers)
        Session().commit()

    def _reject_close(self, pull_request):
        if pull_request.is_closed():
            raise HTTPForbidden()

        PullRequestModel().close_pull_request_with_comment(
            pull_request, c.rhodecode_user, c.rhodecode_db_repo)
        Session().commit()

    @LoginRequired()
    @NotAnonymous()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    @auth.CSRFRequired()
    @jsonify
    def delete(self, repo_name, pull_request_id):
        pull_request_id = safe_int(pull_request_id)
        pull_request = PullRequest.get_or_404(pull_request_id)
        # only owner can delete it !
        if pull_request.author.user_id == c.rhodecode_user.user_id:
            PullRequestModel().delete(pull_request)
            Session().commit()
            h.flash(_('Successfully deleted pull request'),
                    category='success')
            return redirect(url('my_account_pullrequests'))
        raise HTTPForbidden()

    def _get_pr_version(self, pull_request_id, version=None):
        pull_request_id = safe_int(pull_request_id)
        at_version = None

        if version and version == 'latest':
            pull_request_ver = PullRequest.get(pull_request_id)
            pull_request_obj = pull_request_ver
            _org_pull_request_obj = pull_request_obj
            at_version = 'latest'
        elif version:
            pull_request_ver = PullRequestVersion.get_or_404(version)
            pull_request_obj = pull_request_ver
            _org_pull_request_obj = pull_request_ver.pull_request
            at_version = pull_request_ver.pull_request_version_id
        else:
            _org_pull_request_obj = pull_request_obj = PullRequest.get_or_404(pull_request_id)

        pull_request_display_obj = PullRequest.get_pr_display_object(
            pull_request_obj, _org_pull_request_obj)
        return _org_pull_request_obj, pull_request_obj, \
               pull_request_display_obj, at_version

    def _get_pr_version_changes(self, version, pull_request_latest):
        """
        Generate changes commits, and diff data based on the current pr version
        """

        #TODO(marcink): save those changes as JSON metadata for chaching later.

        # fake the version to add the "initial" state object
        pull_request_initial = PullRequest.get_pr_display_object(
            pull_request_latest, pull_request_latest,
            internal_methods=['get_commit', 'versions'])
        pull_request_initial.revisions = []
        pull_request_initial.source_repo.get_commit = types.MethodType(
            lambda *a, **k: EmptyCommit(), pull_request_initial)
        pull_request_initial.source_repo.scm_instance = types.MethodType(
            lambda *a, **k: EmptyRepository(), pull_request_initial)

        _changes_versions = [pull_request_latest] + \
                            list(reversed(c.versions)) + \
                            [pull_request_initial]

        if version == 'latest':
            index = 0
        else:
            for pos, prver in enumerate(_changes_versions):
                ver = getattr(prver, 'pull_request_version_id', -1)
                if ver == safe_int(version):
                    index = pos
                    break
            else:
                index = 0

        cur_obj = _changes_versions[index]
        prev_obj = _changes_versions[index + 1]

        old_commit_ids = set(prev_obj.revisions)
        new_commit_ids = set(cur_obj.revisions)

        changes = PullRequestModel()._calculate_commit_id_changes(
            old_commit_ids, new_commit_ids)

        old_diff_data, new_diff_data = PullRequestModel()._generate_update_diffs(
            cur_obj, prev_obj)
        file_changes = PullRequestModel()._calculate_file_changes(
            old_diff_data, new_diff_data)
        return changes, file_changes

    @LoginRequired()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    def show(self, repo_name, pull_request_id):
        pull_request_id = safe_int(pull_request_id)
        version = request.GET.get('version')
        merge_checks = request.GET.get('merge_checks')

        (pull_request_latest,
         pull_request_at_ver,
         pull_request_display_obj,
         at_version) = self._get_pr_version(pull_request_id, version=version)

        c.template_context['pull_request_data']['pull_request_id'] = \
            pull_request_id

        # pull_requests repo_name we opened it against
        # ie. target_repo must match
        if repo_name != pull_request_at_ver.target_repo.repo_name:
            raise HTTPNotFound

        c.shadow_clone_url = PullRequestModel().get_shadow_clone_url(
            pull_request_at_ver)

        c.ancestor = None  # TODO: add ancestor here
        c.pull_request = pull_request_display_obj
        c.pull_request_latest = pull_request_latest

        pr_closed = pull_request_latest.is_closed()
        if at_version and not at_version == 'latest':
            c.allowed_to_change_status = False
            c.allowed_to_update = False
            c.allowed_to_merge = False
            c.allowed_to_delete = False
            c.allowed_to_comment = False
        else:
            c.allowed_to_change_status = PullRequestModel(). \
                check_user_change_status(pull_request_at_ver, c.rhodecode_user)
            c.allowed_to_update = PullRequestModel().check_user_update(
                pull_request_latest, c.rhodecode_user) and not pr_closed
            c.allowed_to_merge = PullRequestModel().check_user_merge(
                pull_request_latest, c.rhodecode_user) and not pr_closed
            c.allowed_to_delete = PullRequestModel().check_user_delete(
                pull_request_latest, c.rhodecode_user) and not pr_closed
            c.allowed_to_comment = not pr_closed

        cc_model = CommentsModel()

        c.pull_request_reviewers = pull_request_at_ver.reviewers_statuses()
        c.pull_request_review_status = pull_request_at_ver.calculated_review_status()

        c.versions = pull_request_display_obj.versions()
        c.at_version = at_version
        c.at_version_num = at_version if at_version and at_version != 'latest' else None
        c.at_version_pos = ChangesetComment.get_index_from_version(
            c.at_version_num, c.versions)

        # GENERAL COMMENTS with versions #
        q = cc_model._all_general_comments_of_pull_request(pull_request_latest)
        general_comments = q.order_by(ChangesetComment.pull_request_version_id.asc())

        # pick comments we want to render at current version
        c.comment_versions = cc_model.aggregate_comments(
            general_comments, c.versions, c.at_version_num)
        c.comments = c.comment_versions[c.at_version_num]['until']

        # INLINE COMMENTS with versions  #
        q = cc_model._all_inline_comments_of_pull_request(pull_request_latest)
        inline_comments = q.order_by(ChangesetComment.pull_request_version_id.asc())
        c.inline_versions = cc_model.aggregate_comments(
            inline_comments, c.versions, c.at_version_num, inline=True)

        # if we use version, then do not show later comments
        # than current version
        display_inline_comments = collections.defaultdict(lambda: collections.defaultdict(list))
        for co in inline_comments:
            if c.at_version_num:
                # pick comments that are at least UPTO given version, so we
                # don't render comments for higher version
                should_render = co.pull_request_version_id and \
                                co.pull_request_version_id <= c.at_version_num
            else:
                # showing all, for 'latest'
                should_render = True

            if should_render:
                display_inline_comments[co.f_path][co.line_no].append(co)

        _merge_check = MergeCheck.validate(
            pull_request_latest, user=c.rhodecode_user)
        c.pr_merge_errors = _merge_check.errors
        c.pr_merge_possible = not _merge_check.failed
        c.pr_merge_message = _merge_check.merge_msg

        if merge_checks:
            return render('/pullrequests/pullrequest_merge_checks.mako')

        # load compare data into template context
        self._load_compare_data(pull_request_at_ver, display_inline_comments)

        # this is a hack to properly display links, when creating PR, the
        # compare view and others uses different notation, and
        # compare_commits.mako renders links based on the target_repo.
        # We need to swap that here to generate it properly on the html side
        c.target_repo = c.source_repo

        if c.allowed_to_update:
            force_close = ('forced_closed', _('Close Pull Request'))
            statuses = ChangesetStatus.STATUSES + [force_close]
        else:
            statuses = ChangesetStatus.STATUSES
        c.commit_statuses = statuses

        c.changes = None
        c.file_changes = None

        c.show_version_changes = 1  # control flag, not used yet

        if at_version and c.show_version_changes:
            c.changes, c.file_changes = self._get_pr_version_changes(
                version, pull_request_latest)

        return render('/pullrequests/pullrequest_show.mako')

    @LoginRequired()
    @NotAnonymous()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    @auth.CSRFRequired()
    @jsonify
    def comment(self, repo_name, pull_request_id):
        pull_request_id = safe_int(pull_request_id)
        pull_request = PullRequest.get_or_404(pull_request_id)
        if pull_request.is_closed():
            raise HTTPForbidden()

        # TODO: johbo: Re-think this bit, "approved_closed" does not exist
        # as a changeset status, still we want to send it in one value.
        status = request.POST.get('changeset_status', None)
        text = request.POST.get('text')
        comment_type = request.POST.get('comment_type')
        resolves_comment_id = request.POST.get('resolves_comment_id', None)

        if status and '_closed' in status:
            close_pr = True
            status = status.replace('_closed', '')
        else:
            close_pr = False

        forced = (status == 'forced')
        if forced:
            status = 'rejected'

        allowed_to_change_status = PullRequestModel().check_user_change_status(
            pull_request, c.rhodecode_user)

        if status and allowed_to_change_status:
            message = (_('Status change %(transition_icon)s %(status)s')
                       % {'transition_icon': '>',
                          'status': ChangesetStatus.get_status_lbl(status)})
            if close_pr:
                message = _('Closing with') + ' ' + message
            text = text or message
        comm = CommentsModel().create(
            text=text,
            repo=c.rhodecode_db_repo.repo_id,
            user=c.rhodecode_user.user_id,
            pull_request=pull_request_id,
            f_path=request.POST.get('f_path'),
            line_no=request.POST.get('line'),
            status_change=(ChangesetStatus.get_status_lbl(status)
                           if status and allowed_to_change_status else None),
            status_change_type=(status
                                if status and allowed_to_change_status else None),
            closing_pr=close_pr,
            comment_type=comment_type,
            resolves_comment_id=resolves_comment_id
        )

        if allowed_to_change_status:
            old_calculated_status = pull_request.calculated_review_status()
            # get status if set !
            if status:
                ChangesetStatusModel().set_status(
                    c.rhodecode_db_repo.repo_id,
                    status,
                    c.rhodecode_user.user_id,
                    comm,
                    pull_request=pull_request_id
                )

            Session().flush()
            events.trigger(events.PullRequestCommentEvent(pull_request, comm))
            # we now calculate the status of pull request, and based on that
            # calculation we set the commits status
            calculated_status = pull_request.calculated_review_status()
            if old_calculated_status != calculated_status:
                PullRequestModel()._trigger_pull_request_hook(
                    pull_request, c.rhodecode_user, 'review_status_change')

            calculated_status_lbl = ChangesetStatus.get_status_lbl(
                calculated_status)

            if close_pr:
                status_completed = (
                    calculated_status in [ChangesetStatus.STATUS_APPROVED,
                                          ChangesetStatus.STATUS_REJECTED])
                if forced or status_completed:
                    PullRequestModel().close_pull_request(
                        pull_request_id, c.rhodecode_user)
                else:
                    h.flash(_('Closing pull request on other statuses than '
                              'rejected or approved is forbidden. '
                              'Calculated status from all reviewers '
                              'is currently: %s') % calculated_status_lbl,
                            category='warning')

        Session().commit()

        if not request.is_xhr:
            return redirect(h.url('pullrequest_show', repo_name=repo_name,
                                  pull_request_id=pull_request_id))

        data = {
            'target_id': h.safeid(h.safe_unicode(request.POST.get('f_path'))),
        }
        if comm:
            c.co = comm
            c.inline_comment = True if comm.line_no else False
            data.update(comm.get_dict())
            data.update({'rendered_text':
                             render('changeset/changeset_comment_block.mako')})

        return data

    @LoginRequired()
    @NotAnonymous()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    @auth.CSRFRequired()
    @jsonify
    def delete_comment(self, repo_name, comment_id):
        return self._delete_comment(comment_id)

    def _delete_comment(self, comment_id):
        comment_id = safe_int(comment_id)
        co = ChangesetComment.get_or_404(comment_id)
        if co.pull_request.is_closed():
            # don't allow deleting comments on closed pull request
            raise HTTPForbidden()

        is_owner = co.author.user_id == c.rhodecode_user.user_id
        is_repo_admin = h.HasRepoPermissionAny('repository.admin')(c.repo_name)
        if h.HasPermissionAny('hg.admin')() or is_repo_admin or is_owner:
            old_calculated_status = co.pull_request.calculated_review_status()
            CommentsModel().delete(comment=co)
            Session().commit()
            calculated_status = co.pull_request.calculated_review_status()
            if old_calculated_status != calculated_status:
                PullRequestModel()._trigger_pull_request_hook(
                    co.pull_request, c.rhodecode_user, 'review_status_change')
            return True
        else:
            raise HTTPForbidden()