1 files changed, 85 insertions, 12 deletions

diff --git a/app/assets/javascripts/notes/stores/getters.js b/app/assets/javascripts/notes/stores/getters.js
index 5c65e1c3bb5..0d8d197bf71 100644
--- a/app/assets/javascripts/notes/stores/getters.js
+++ b/app/assets/javascripts/notes/stores/getters.js
@@ -28,18 +28,6 @@ export const notesById = state =>
     return acc;
   }, {});
 
-export const discussionsByLineCode = state =>
-  state.discussions.reduce((acc, note) => {
-    if (note.diff_discussion && note.line_code && note.resolvable) {
-      // For context about line notes: there might be multiple notes with the same line code
-      const items = acc[note.line_code] || [];
-      items.push(note);
-
-      Object.assign(acc, { [note.line_code]: items });
-    }
-    return acc;
-  }, {});
-
 export const noteableType = state => {
   const { ISSUE_NOTEABLE_TYPE, MERGE_REQUEST_NOTEABLE_TYPE, EPIC_NOTEABLE_TYPE } = constants;
 
@@ -82,6 +70,9 @@ export const allDiscussions = (state, getters) => {
   return Object.values(resolved).concat(unresolved);
 };
 
+export const allResolvableDiscussions = (state, getters) =>
+  getters.allDiscussions.filter(d => !d.individual_note && d.resolvable);
+
 export const resolvedDiscussionsById = state => {
   const map = {};
 
@@ -98,6 +89,51 @@ export const resolvedDiscussionsById = state => {
   return map;
 };
 
+// Gets Discussions IDs ordered by the date of their initial note
+export const unresolvedDiscussionsIdsByDate = (state, getters) =>
+  getters.allResolvableDiscussions
+    .filter(d => !d.resolved)
+    .sort((a, b) => {
+      const aDate = new Date(a.notes[0].created_at);
+      const bDate = new Date(b.notes[0].created_at);
+
+      if (aDate < bDate) {
+        return -1;
+      }
+
+      return aDate === bDate ? 0 : 1;
+    })
+    .map(d => d.id);
+
+// Gets Discussions IDs ordered by their position in the diff
+//
+// Sorts the array of resolvable yet unresolved discussions by
+// comparing file names first. If file names are the same, compares
+// line numbers.
+export const unresolvedDiscussionsIdsByDiff = (state, getters) =>
+  getters.allResolvableDiscussions
+    .filter(d => !d.resolved)
+    .sort((a, b) => {
+      if (!a.diff_file || !b.diff_file) {
+        return 0;
+      }
+
+      // Get file names comparison result
+      const filenameComparison = a.diff_file.file_path.localeCompare(b.diff_file.file_path);
+
+      // Get the line numbers, to compare within the same file
+      const aLines = [a.position.formatter.new_line, a.position.formatter.old_line];
+      const bLines = [b.position.formatter.new_line, b.position.formatter.old_line];
+
+      return filenameComparison < 0 ||
+        (filenameComparison === 0 &&
+          // .max() because one of them might be zero (if removed/added)
+          Math.max(aLines[0], aLines[1]) < Math.max(bLines[0], bLines[1]))
+        ? -1
+        : 1;
+    })
+    .map(d => d.id);
+
 export const resolvedDiscussionCount = (state, getters) => {
   const resolvedMap = getters.resolvedDiscussionsById;
 
@@ -114,5 +150,42 @@ export const discussionTabCounter = state => {
   return all.length;
 };
 
+// Returns the list of discussion IDs ordered according to given parameter
+// @param {Boolean} diffOrder - is ordered by diff?
+export const unresolvedDiscussionsIdsOrdered = (state, getters) => diffOrder => {
+  if (diffOrder) {
+    return getters.unresolvedDiscussionsIdsByDiff;
+  }
+  return getters.unresolvedDiscussionsIdsByDate;
+};
+
+// Checks if a given discussion is the last in the current order (diff or date)
+// @param {Boolean} discussionId - id of the discussion
+// @param {Boolean} diffOrder - is ordered by diff?
+export const isLastUnresolvedDiscussion = (state, getters) => (discussionId, diffOrder) => {
+  const idsOrdered = getters.unresolvedDiscussionsIdsOrdered(diffOrder);
+  const lastDiscussionId = idsOrdered[idsOrdered.length - 1];
+
+  return lastDiscussionId === discussionId;
+};
+
+// Gets the ID of the discussion following the one provided, respecting order (diff or date)
+// @param {Boolean} discussionId - id of the current discussion
+// @param {Boolean} diffOrder - is ordered by diff?
+export const nextUnresolvedDiscussionId = (state, getters) => (discussionId, diffOrder) => {
+  const idsOrdered = getters.unresolvedDiscussionsIdsOrdered(diffOrder);
+  const currentIndex = idsOrdered.indexOf(discussionId);
+
+  return idsOrdered.slice(currentIndex + 1, currentIndex + 2)[0];
+};
+
+// @param {Boolean} diffOrder - is ordered by diff?
+export const firstUnresolvedDiscussionId = (state, getters) => diffOrder => {
+  if (diffOrder) {
+    return getters.unresolvedDiscussionsIdsByDiff[0];
+  }
+  return getters.unresolvedDiscussionsIdsByDate[0];
+};
+
 // prevent babel-plugin-rewire from generating an invalid default during karma tests
 export default () => {};