1 files changed, 83 insertions, 10 deletions

diff --git a/app/models/diff_note.rb b/app/models/diff_note.rb
index c816deb4e0c..559b3075905 100644
--- a/app/models/diff_note.rb
+++ b/app/models/diff_note.rb
@@ -9,17 +9,37 @@ class DiffNote < Note
   validates :diff_line, presence: true
   validates :line_code, presence: true, line_code: true
   validates :noteable_type, inclusion: { in: ['Commit', 'MergeRequest'] }
+  validates :resolved_by, presence: true, if: :resolved?
   validate :positions_complete
   validate :verify_supported
 
+  # Keep this scope in sync with the logic in `#resolvable?`
+  scope :resolvable, -> { user.where(noteable_type: 'MergeRequest') }
+  scope :resolved, -> { resolvable.where.not(resolved_at: nil) }
+  scope :unresolved, -> { resolvable.where(resolved_at: nil) }
+
+  after_initialize :ensure_original_discussion_id
   before_validation :set_original_position, :update_position, on: :create
-  before_validation :set_line_code
+  before_validation :set_line_code, :set_original_discussion_id
+  # We need to do this again, because it's already in `Note`, but is affected by
+  # `update_position` and needs to run after that.
+  before_validation :set_discussion_id
   after_save :keep_around_commits
 
   class << self
     def build_discussion_id(noteable_type, noteable_id, position)
       [super(noteable_type, noteable_id), *position.key].join("-")
     end
+
+    # This method must be kept in sync with `#resolve!`
+    def resolve!(current_user)
+      unresolved.update_all(resolved_at: Time.now, resolved_by_id: current_user.id)
+    end
+
+    # This method must be kept in sync with `#unresolve!`
+    def unresolve!
+      resolved.update_all(resolved_at: nil, resolved_by_id: nil)
+    end
   end
 
   def new_diff_note?
@@ -30,14 +50,6 @@ class DiffNote < Note
     { 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
@@ -63,6 +75,10 @@ class DiffNote < Note
     diff_file.position(line) == self.original_position
   end
 
+  def original_line_code
+    self.diff_file.line_code(self.diff_line)
+  end
+
   def active?(diff_refs = nil)
     return false unless supported?
     return true if for_commit?
@@ -72,10 +88,47 @@ class DiffNote < Note
     self.position.diff_refs == diff_refs
   end
 
+  # If you update this method remember to also update the scope `resolvable`
+  def resolvable?
+    !system? && for_merge_request?
+  end
+
+  def resolved?
+    return false unless resolvable?
+
+    self.resolved_at.present?
+  end
+
+  # If you update this method remember to also update `.resolve!`
+  def resolve!(current_user)
+    return unless resolvable?
+    return if resolved?
+
+    self.resolved_at = Time.now
+    self.resolved_by = current_user
+    save!
+  end
+
+  # If you update this method remember to also update `.unresolve!`
+  def unresolve!
+    return unless resolvable?
+    return unless resolved?
+
+    self.resolved_at = nil
+    self.resolved_by = nil
+    save!
+  end
+
+  def discussion
+    return unless resolvable?
+
+    self.noteable.find_diff_discussion(self.discussion_id)
+  end
+
   private
 
   def supported?
-    !self.for_merge_request? || self.noteable.support_new_diff_notes?
+    for_commit? || self.noteable.has_complete_diff_refs?
   end
 
   def noteable_diff_refs
@@ -94,6 +147,26 @@ class DiffNote < Note
     self.line_code = self.position.line_code(self.project.repository)
   end
 
+  def ensure_original_discussion_id
+    return unless self.persisted?
+    return if self.original_discussion_id
+
+    set_original_discussion_id
+    update_column(:original_discussion_id, self.original_discussion_id)
+  end
+
+  def set_original_discussion_id
+    self.original_discussion_id = Digest::SHA1.hexdigest(build_original_discussion_id)
+  end
+
+  def build_discussion_id
+    self.class.build_discussion_id(noteable_type, noteable_id || commit_id, position)
+  end
+
+  def build_original_discussion_id
+    self.class.build_discussion_id(noteable_type, noteable_id || commit_id, original_position)
+  end
+
   def update_position
     return unless supported?
     return if for_commit?