2 files changed, 105 insertions, 2 deletions

diff --git a/app/models/diff_note.rb b/app/models/diff_note.rb
new file mode 100644
index 00000000000..94c07cc535c
--- /dev/null
+++ b/app/models/diff_note.rb
@@ -0,0 +1,99 @@
+class DiffNote < Note
+  include NoteOnDiff
+
+  serialize :original_position, Gitlab::Diff::Position
+  serialize :position, Gitlab::Diff::Position
+
+  validates :original_position, presence: true
+  validates :position, presence: true
+  validates :diff_line, presence: true
+  validates :line_code, presence: true, line_code: true
+  validates :noteable_type, inclusion: { in: ['Commit', 'MergeRequest'] }
+  validate :positions_complete
+  validate :verify_supported
+
+  before_validation :set_original_position, on: :create
+  before_validation :set_line_code
+
+  class << self
+    def build_discussion_id(noteable_type, noteable_id, position)
+      [super(noteable_type, noteable_id), *position.key].join("-")
+    end
+  end
+
+  def new_diff_note?
+    true
+  end
+
+  def diff_attributes
+    { position: position.to_json }
+  end
+
+  def discussion_id
+    @discussion_id ||= self.class.build_discussion_id(noteable_type, noteable_id || commit_id, position)
+  end
+
+  def original_discussion_id
+    @original_discussion_id ||= self.class.build_discussion_id(noteable_type, noteable_id || commit_id, original_position)
+  end
+
+  def position=(new_position)
+    if new_position.is_a?(String)
+      new_position = JSON.parse(new_position) rescue nil
+    end
+
+    if new_position.is_a?(Hash)
+      new_position = new_position.with_indifferent_access
+      new_position = Gitlab::Diff::Position.new(new_position)
+    end
+
+    super(new_position)
+  end
+
+  def diff_file
+    @diff_file ||= self.original_position.diff_file(self.project.repository)
+  end
+
+  def diff_line
+    @diff_line ||= diff_file.line_for_position(self.original_position) if diff_file
+  end
+
+  def for_line?(line)
+    diff_file.position(line) == self.original_position
+  end
+
+  def active?(diff_refs = nil)
+    return false unless supported?
+    return true if for_commit?
+
+    diff_refs ||= self.noteable.diff_refs
+
+    self.position.diff_refs == diff_refs
+  end
+
+  private
+
+  def supported?
+    !self.for_merge_request?
+  end
+
+  def set_original_position
+    self.original_position = self.position.dup
+  end
+
+  def set_line_code
+    self.line_code = self.position.line_code(self.project.repository)
+  end
+
+  def verify_supported
+    return if supported?
+
+    errors.add(:noteable, "doesn't support new-style diff notes")
+  end
+
+  def positions_complete
+    return if self.original_position.complete? && self.position.complete?
+
+    errors.add(:position, "is invalid")
+  end
+end
diff --git a/app/models/note.rb b/app/models/note.rb
index 0c265064630..ffffd0c0838 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -56,7 +56,7 @@ class Note < ActiveRecord::Base
   scope :inc_author, ->{ includes(:author) }
   scope :inc_author_project_award_emoji, ->{ includes(:project, :author, :award_emoji) }
 
-  scope :legacy_diff_notes, ->{ where(type: 'LegacyDiffNote') }
+  scope :diff_notes, ->{ where(type: ['LegacyDiffNote', 'DiffNote']) }
   scope :non_diff_notes, ->{ where(type: ['Note', nil]) }
 
   scope :with_associations, -> do
@@ -82,7 +82,7 @@ class Note < ActiveRecord::Base
     end
 
     def grouped_diff_notes
-      legacy_diff_notes.select(&:active?).sort_by(&:created_at).group_by(&:line_code)
+      diff_notes.select(&:active?).sort_by(&:created_at).group_by(&:line_code)
     end
 
     # Searches for notes matching the given query.
@@ -115,6 +115,10 @@ class Note < ActiveRecord::Base
     false
   end
 
+  def new_diff_note?
+    false
+  end
+
   def active?
     true
   end