Merge branch 'discussion-model' into 'master'

Add Discussion model to represent MR/diff discussion

Related to https://gitlab.com/gitlab-org/gitlab-ce/issues/10325.

See merge request !5376

3 files changed, 95 insertions, 28 deletions

diff --git a/app/models/concerns/note_on_diff.rb b/app/models/concerns/note_on_diff.rb
index 2785fbb21c9..4be6a2f621b 100644
--- a/app/models/concerns/note_on_diff.rb
+++ b/app/models/concerns/note_on_diff.rb
@@ -1,12 +1,6 @@
 module NoteOnDiff
   extend ActiveSupport::Concern
 
-  NUMBER_OF_TRUNCATED_DIFF_LINES = 16
-
-  included do
-    delegate :blob, :highlighted_diff_lines, to: :diff_file, allow_nil: true
-  end
-
   def diff_note?
     true
   end
@@ -30,23 +24,4 @@ module NoteOnDiff
   def can_be_award_emoji?
     false
   end
-
-  # Returns an array of at most 16 highlighted lines above a diff note
-  def truncated_diff_lines
-    prev_lines = []
-
-    highlighted_diff_lines.each do |line|
-      if line.meta?
-        prev_lines.clear
-      else
-        prev_lines << line
-
-        break if for_line?(line)
-
-        prev_lines.shift if prev_lines.length >= NUMBER_OF_TRUNCATED_DIFF_LINES
-      end
-    end
-
-    prev_lines
-  end
 end
diff --git a/app/models/discussion.rb b/app/models/discussion.rb
new file mode 100644
index 00000000000..74facfd1c9c
--- /dev/null
+++ b/app/models/discussion.rb
@@ -0,0 +1,91 @@
+class Discussion
+  NUMBER_OF_TRUNCATED_DIFF_LINES = 16
+
+  attr_reader :first_note, :notes
+
+  delegate  :created_at,
+            :project,
+            :author,
+
+            :noteable,
+            :for_commit?,
+            :for_merge_request?,
+
+            :line_code,
+            :diff_file,
+            :for_line?,
+            :active?,
+
+            to: :first_note
+
+  delegate :blob, :highlighted_diff_lines, to: :diff_file, allow_nil: true
+
+  def self.for_notes(notes)
+    notes.group_by(&:discussion_id).values.map { |notes| new(notes) }
+  end
+
+  def self.for_diff_notes(notes)
+    notes.group_by(&:line_code).values.map { |notes| new(notes) }
+  end
+
+  def initialize(notes)
+    @first_note = notes.first
+    @notes = notes
+  end
+
+  def id
+    first_note.discussion_id
+  end
+
+  def diff_discussion?
+    first_note.diff_note?
+  end
+
+  def legacy_diff_discussion?
+    notes.any?(&:legacy_diff_note?)
+  end
+
+  def for_target?(target)
+    self.noteable == target && !diff_discussion?
+  end
+
+  def expanded?
+    !diff_discussion? || active?
+  end
+
+  def reply_attributes
+    data = {
+      noteable_type: first_note.noteable_type,
+      noteable_id:   first_note.noteable_id,
+      commit_id:     first_note.commit_id,
+      discussion_id: self.id,
+    }
+
+    if diff_discussion?
+      data[:note_type] = first_note.type
+
+      data.merge!(first_note.diff_attributes)
+    end
+
+    data
+  end
+
+  # Returns an array of at most 16 highlighted lines above a diff note
+  def truncated_diff_lines
+    prev_lines = []
+
+    highlighted_diff_lines.each do |line|
+      if line.meta?
+        prev_lines.clear
+      else
+        prev_lines << line
+
+        break if for_line?(line)
+
+        prev_lines.shift if prev_lines.length >= NUMBER_OF_TRUNCATED_DIFF_LINES
+      end
+    end
+
+    prev_lines
+  end
+end
diff --git a/app/models/note.rb b/app/models/note.rb
index 0ce10c77de9..9b0a7211b4e 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -82,11 +82,12 @@ class Note < ActiveRecord::Base
     end
 
     def discussions
-      all.group_by(&:discussion_id).values
+      Discussion.for_notes(all)
     end
 
-    def grouped_diff_notes
-      diff_notes.select(&:active?).sort_by(&:created_at).group_by(&:line_code)
+    def grouped_diff_discussions
+      notes = diff_notes.fresh.select(&:active?)
+      Discussion.for_diff_notes(notes).map { |d| [d.line_code, d] }.to_h
     end
 
     # Searches for notes matching the given query.