1 files changed, 82 insertions, 0 deletions
diff --git a/app/presenters/gitlab/blame_presenter.rb b/app/presenters/gitlab/blame_presenter.rb
new file mode 100644
index 00000000000..db2fc52a88b
--- /dev/null
+++ b/app/presenters/gitlab/blame_presenter.rb
@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+module Gitlab
+  class BlamePresenter < Gitlab::View::Presenter::Simple
+    include ActionView::Helpers::UrlHelper
+    include ActionView::Helpers::TranslationHelper
+    include ActionView::Context
+    include AvatarsHelper
+    include BlameHelper
+    include CommitsHelper
+    include ApplicationHelper
+    include TreeHelper
+    include IconsHelper
+
+    presents :blame
+
+    CommitData = Struct.new(
+      :author_avatar,
+      :age_map_class,
+      :commit_link,
+      :commit_author_link,
+      :project_blame_link,
+      :time_ago_tooltip)
+
+    def initialize(subject, **attributes)
+      super
+
+      @commits = {}
+      precalculate_data_by_commit!
+    end
+
+    def groups
+      @groups ||= blame.groups
+    end
+
+    def commit_data(commit)
+      @commits[commit.id] ||= get_commit_data(commit)
+    end
+
+    private
+
+    # Huge source files with a high churn rate (e.g. 'locale/gitlab.pot') could have
+    # 10x times more blame groups than unique commits across all the groups.
+    # That means we could cache per-commit data we need
+    # to avoid recalculating it multiple times.
+    # For such files, it could significantly improve the performance of the Blame.
+    def precalculate_data_by_commit!
+      groups.each { |group| commit_data(group[:commit]) }
+    end
+
+    def get_commit_data(commit)
+      CommitData.new.tap do |data|
+        data.author_avatar = author_avatar(commit, size: 36, has_tooltip: false)
+        data.age_map_class = age_map_class(commit.committed_date, project_duration)
+        data.commit_link = link_to commit.title, project_commit_path(project, commit.id), class: "cdark", title: commit.title
+        data.commit_author_link = commit_author_link(commit, avatar: false)
+        data.project_blame_link = project_blame_link(commit)
+        data.time_ago_tooltip = time_ago_with_tooltip(commit.committed_date)
+      end
+    end
+
+    def project_blame_link(commit)
+      previous_commit_id = commit.parent_id
+      return unless previous_commit_id
+
+      link_to project_blame_path(project, tree_join(previous_commit_id, path)),
+        title: _('View blame prior to this change'),
+        aria: { label: _('View blame prior to this change') },
+        data: { toggle: 'tooltip', placement: 'right', container: 'body' } do
+          versions_sprite_icon
+        end
+    end
+
+    def project_duration
+      @project_duration ||= age_map_duration(groups, project)
+    end
+
+    def versions_sprite_icon
+      @versions_sprite_icon ||= sprite_icon('doc-versions', size: 16, css_class: 'doc-versions align-text-bottom')
+    end
+  end
+end