class CompareController(BaseRepoController):

    def __before__(self):

        super(CompareController, self).__before__()

    def __get_rev_or_redirect(self, ref, repo, redirect_after=True,

                              partial=False):

        """

        Safe way to get changeset if error occur it redirects to changeset with

        proper message. If partial is set then don't do redirect raise Exception

        instead

        :param ref:

        :param repo:

        :param redirect_after:

        :param partial:

        """

        rev = ref[1] # default and used for git

        if repo.scm_instance.alias == 'hg':

            # lookup up the exact node id

            _revset_predicates = {

                    'branch': 'branch',

                    'book': 'bookmark',

                    'tag': 'tag',

                    'rev': 'id',

                }

            rev_spec = "max(%s(%%s))" % _revset_predicates[ref[0]]

            revs = repo.scm_instance._repo.revs(rev_spec, safe_str(ref[1]))

            if revs:

                rev = revs[-1]

            # else: TODO: just report 'not found'

        try:

            return repo.scm_instance.get_changeset(rev).raw_id

        except EmptyRepositoryError, e:

            if not redirect_after:

                return None

            h.flash(h.literal(_('There are no changesets yet')),

                    category='warning')

            redirect(url('summary_home', repo_name=repo.repo_name))

        except RepositoryError, e:

            log.error(traceback.format_exc())

            h.flash(safe_str(e), category='warning')

            if not partial:

                redirect(h.url('summary_home', repo_name=repo.repo_name))

            raise HTTPBadRequest()

        """

        Returns a list of changesets that can be merged from org_repo at org_rev

        to other_repo at other_rev ... and the ancestor that would be used for merge.

        :param org_repo: repo object, that is most likely the orginal repo we forked from

        :param org_rev: the revision we want our compare to be made

        :param other_repo: repo object, mostl likely the fork of org_repo. It hass

            all changesets that we need to obtain

        :param other_rev: revision we want out compare to be made on other_repo

        """

        ancestor = None

        if org_rev == other_rev:

            changesets = []

        elif alias == 'hg':

            #case two independent repos

            if org_repo != other_repo:

                hgrepo = unionrepo.unionrepository(other_repo.baseui,

                                                   other_repo.path,

                                                   org_repo.path)

                # all the changesets we are looking for will be in other_repo,

                # so rev numbers from hgrepo can be used in other_repo

            #no remote compare do it on the same repository

            else:

                hgrepo = other_repo._repo

            changesets = [other_repo.get_changeset(rev) for rev in revs]

        elif alias == 'git':

            if org_repo != other_repo:

                from dulwich.repo import Repo

                from dulwich.client import SubprocessGitClient

                gitrepo = Repo(org_repo.path)

                SubprocessGitClient(thin_packs=False).fetch(other_repo.path, gitrepo)

                gitrepo_remote = Repo(other_repo.path)

                SubprocessGitClient(thin_packs=False).fetch(org_repo.path, gitrepo_remote)

                revs = []

                for x in gitrepo_remote.get_walker(include=[other_rev],

                                                   exclude=[org_rev]):

                    revs.append(x.commit.id)

                changesets = [other_repo.get_changeset(rev) for rev in reversed(revs)]

                if changesets:

                    ancestor = changesets[0].parents[0].raw_id

                else:

                    # no changesets from other repo, ancestor is the other_rev

                    ancestor = other_rev

            else:

                so, se = org_repo.run_git_command(

                    'log --reverse --pretty="format: %%H" -s %s..%s'

                        % (org_rev, other_rev)

                )

                changesets = [org_repo.get_changeset(cs)

                              for cs in re.findall(r'[0-9a-fA-F]{40}', so)]

        else:

            raise Exception('Bad alias only git and hg is allowed')

        return changesets, ancestor

    @LoginRequired()

    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',

                                   'repository.admin')

    def index(self, repo_name):

        c.compare_home = True

        org_repo = c.db_repo.repo_name

        other_repo = request.GET.get('other_repo', org_repo)

        c.org_repo = Repository.get_by_repo_name(org_repo)

        c.other_repo = Repository.get_by_repo_name(other_repo)

        # fulldiff disables cut_off_limit

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

        # partial uses compare_cs.html template directly

        partial = request.environ.get('HTTP_X_PARTIAL_XHR')

        # as_form puts hidden input field with changeset revisions

        c.as_form = partial and request.GET.get('as_form')

        # swap url for compare_diff page - never partial and never as_form

        c.swap_url = h.url('compare_url',

            repo_name=other_repo,

            org_ref_type=other_ref_type, org_ref_name=other_ref_name,

            other_repo=org_repo,

            other_ref_type=org_ref_type, other_ref_name=org_ref_name,

            merge=merge or '')

        org_repo = Repository.get_by_repo_name(org_repo)

        other_repo = Repository.get_by_repo_name(other_repo)

        if org_repo is None:

            msg = 'Could not find org repo %s' % org_repo

            log.error(msg)

            h.flash(msg, category='error')

            return redirect(url('compare_home', repo_name=c.repo_name))

        if other_repo is None:

            msg = 'Could not find other repo %s' % other_repo

            log.error(msg)

            h.flash(msg, category='error')

            return redirect(url('compare_home', repo_name=c.repo_name))

        if org_repo.scm_instance.alias != other_repo.scm_instance.alias:

            msg = 'compare of two different kind of remote repos not available'

            log.error(msg)

            h.flash(msg, category='error')

            return redirect(url('compare_home', repo_name=c.repo_name))

        c.org_rev = self.__get_rev_or_redirect(ref=org_ref, repo=org_repo, partial=partial)

        c.other_rev = self.__get_rev_or_redirect(ref=other_ref, repo=other_repo, partial=partial)

        c.compare_home = False

        c.org_repo = org_repo

        c.other_repo = other_repo

        c.org_ref_name = org_ref_name

        c.other_ref_name = other_ref_name

        c.org_ref_type = org_ref_type

        c.other_ref_type = other_ref_type

        c.cs_ranges, c.ancestor = self._get_changesets(

            org_repo.scm_instance.alias, org_repo.scm_instance, c.org_rev,

        c.statuses = c.db_repo.statuses(

            [x.raw_id for x in c.cs_ranges])

        if partial:

            return render('compare/compare_cs.html')

            # case we want a simple diff without incoming changesets,

            # previewing what will be merged.

            # Make the diff on the other repo (which is known to have other_rev)

            log.debug('Using ancestor %s as rev1 instead of %s'

                      % (c.ancestor, c.org_rev))

            rev1 = c.ancestor

            org_repo = other_repo

        else: # comparing tips, not necessarily linearly related

            if merge:

                log.error('Unable to find ancestor revision')

            if org_repo != other_repo:

                log.error('cannot compare across repos %s and %s', org_repo, other_repo)

                raise HTTPNotFound

            rev1 = c.org_rev

        diff_limit = self.cut_off_limit if not c.fulldiff else None

        log.debug('running diff between %s and %s in %s'

                  % (rev1, c.other_rev, org_repo.scm_instance.path))

        txtdiff = org_repo.scm_instance.get_diff(rev1=rev1, rev2=c.other_rev)

        diff_processor = diffs.DiffProcessor(txtdiff or '', format='gitdiff',

                                             diff_limit=diff_limit)

        _parsed = diff_processor.prepare()

        c.limited_diff = False

        if isinstance(_parsed, LimitedDiffContainer):

            c.limited_diff = True

        c.files = []

        c.changes = {}

        c.lines_added = 0

        c.lines_deleted = 0

        for f in _parsed:

            st = f['stats']

            if not st['binary']:

                c.lines_added += st['added']

                c.lines_deleted += st['deleted']

            fid = h.FID('', f['filename'])

            c.files.append([fid, f['operation'], f['filename'], f['stats']])

            htmldiff = diff_processor.as_html(enable_comments=False, parsed_lines=[f])

            c.changes[fid] = [f['operation'], f['filename'], htmldiff]

        return render('compare/compare_diff.html')

## Changesets table !

<div class="container">

  %if not c.cs_ranges:

    <span class="empty_data">${_('No changesets')}</span>

  %else:

    %if c.ancestor:

    <div class="ancestor">${_('Ancestor')}:

      ${h.link_to(h.short_id(c.ancestor),h.url('changeset_home',repo_name=c.repo_name,revision=c.ancestor))}

    </div>

    %endif

    <table class="compare_view_commits noborder">

    %for cs in reversed(c.cs_ranges):

        <tr id="row-${cs.raw_id}">

        <td style="width:50px">

          %if cs.raw_id in c.statuses:

            <div title="${_('Changeset status: %s') % c.statuses[cs.raw_id][1]}" class="changeset-status-ico">

                <img src="${h.url('/images/icons/flag_status_%s.png' % c.statuses[cs.raw_id][0])}" />

            </div>

          %endif

        </td>

        <td style="width: 140px"><span class="tooltip" title="${h.tooltip(h.age(cs.date))}">${cs.date}</span></td>

        <td><div class="gravatar" commit_id="${cs.raw_id}"><img alt="gravatar" src="${h.gravatar_url(h.email_or_none(cs.author),14)}"/></div></td>

        <td><div class="author">${h.person(cs.author)}</div></td>

        <td>${h.link_to('r%s:%s' % (cs.revision,h.short_id(cs.raw_id)),h.url('changeset_home',repo_name=c.other_repo.repo_name,revision=cs.raw_id))}

        %if c.as_form:

          ${h.hidden('revisions',cs.raw_id)}

        %endif

        </td>

        <td>

        %if cs.branch:

        <span class="branchtag">${cs.branch}</span>

        %endif

        </td>

        <td class="expand_commit" commit_id="${cs.raw_id}" title="${_('Expand commit message')}">

            <i class="icon-resize-vertical" style="color:#DDD"></i>

        </td>

        <td><div id="C-${cs.raw_id}" class="message" style="white-space:normal; height:1.1em; padding:0">${h.urlify_commit(cs.message, c.repo_name)}</div></td>

        </tr>

    %endfor

    </table>

    %if c.as_form:

      ${h.hidden('ancestor_rev',c.ancestor)}

      ${h.hidden('merge_rev',c.cs_ranges[-1].raw_id)}

    %endif

  %endif

</div>

<script>

$('.expand_commit').on('click',function(e){

    $(this).children('i').hide();

    var cid = $(this).attr('commit_id');

    $('#C-'+cid).css({'height': 'auto','width': 'auto', 'white-space': 'pre'})

});

$('.gravatar').on('click',function(e){

    var cid = $(this).attr('commit_id');

    $('#row-'+cid).toggleClass('hl', !$('#row-'+cid).hasClass('hl'));

});

</script>