1 files changed, 87 insertions, 0 deletions
diff --git a/lib/gitlab/github_import/representation/diff_note.rb b/lib/gitlab/github_import/representation/diff_note.rb
new file mode 100644
index 00000000000..bb7439a0641
--- /dev/null
+++ b/lib/gitlab/github_import/representation/diff_note.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module GithubImport
+    module Representation
+      class DiffNote
+        include ToHash
+        include ExposeAttribute
+
+        attr_reader :attributes
+
+        expose_attribute :noteable_type, :noteable_id, :commit_id, :file_path,
+                         :diff_hunk, :author, :note, :created_at, :updated_at,
+                         :github_id
+
+        NOTEABLE_ID_REGEX = /\/pull\/(?<iid>\d+)/i
+
+        # Builds a diff note from a GitHub API response.
+        #
+        # note - An instance of `Sawyer::Resource` containing the note details.
+        def self.from_api_response(note)
+          matches = note.html_url.match(NOTEABLE_ID_REGEX)
+
+          unless matches
+            raise(
+              ArgumentError,
+              "The note URL #{note.html_url.inspect} is not supported"
+            )
+          end
+
+          user = Representation::User.from_api_response(note.user) if note.user
+          hash = {
+            noteable_type: 'MergeRequest',
+            noteable_id: matches[:iid].to_i,
+            file_path: note.path,
+            commit_id: note.commit_id,
+            diff_hunk: note.diff_hunk,
+            author: user,
+            note: note.body,
+            created_at: note.created_at,
+            updated_at: note.updated_at,
+            github_id: note.id
+          }
+
+          new(hash)
+        end
+
+        # Builds a new note using a Hash that was built from a JSON payload.
+        def self.from_json_hash(raw_hash)
+          hash = Representation.symbolize_hash(raw_hash)
+          hash[:author] &&= Representation::User.from_json_hash(hash[:author])
+
+          new(hash)
+        end
+
+        # attributes - A Hash containing the raw note details. The keys of this
+        #              Hash must be Symbols.
+        def initialize(attributes)
+          @attributes = attributes
+        end
+
+        def line_code
+          diff_line = Gitlab::Diff::Parser.new.parse(diff_hunk.lines).to_a.last
+
+          Gitlab::Git
+            .diff_line_code(file_path, diff_line.new_pos, diff_line.old_pos)
+        end
+
+        # Returns a Hash that can be used to populate `notes.st_diff`, removing
+        # the need for requesting Git data for every diff note.
+        def diff_hash
+          {
+            diff: diff_hunk,
+            new_path: file_path,
+            old_path: file_path,
+
+            # These fields are not displayed for LegacyDiffNote notes, so it
+            # doesn't really matter what we set them to.
+            a_mode: '100644',
+            b_mode: '100644',
+            new_file: false
+          }
+        end
+      end
+    end
+  end
+end