feat: explain Following changes before review (Closes #1322)

src/following_store.py

@@ -112,6 +112,16 @@ class FollowingStore:
             if not isinstance(kept_updated_at, str) or not kept_updated_at or len(kept_updated_at) > 64:
                 raise ValueError("kept update is invalid")
             item["kept_updated_at"] = kept_updated_at
+        reviewed_title = raw.get("reviewed_title")
+        if reviewed_title is not None:
+            if not isinstance(reviewed_title, str) or not reviewed_title.strip() or len(reviewed_title.strip()) > 300:
+                raise ValueError("reviewed title is invalid")
+            item["reviewed_title"] = reviewed_title.strip()
+        reviewed_state = raw.get("reviewed_state")
+        if reviewed_state is not None:
+            if reviewed_state not in _STATES:
+                raise ValueError("reviewed state is invalid")
+            item["reviewed_state"] = reviewed_state
         return item
 
     @classmethod
@@ -123,8 +133,19 @@ class FollowingStore:
             unseen = (stored["updated_at"] != stored["last_seen_updated_at"] or
                       stored.get("kept_updated_at") == stored["updated_at"])
             item = {key: value for key, value in stored.items()
-                    if key not in {"last_seen_updated_at", "kept_updated_at"}}
+                    if key not in {"last_seen_updated_at", "kept_updated_at",
+                                   "reviewed_title", "reviewed_state"}}
             item["has_unseen_change"] = unseen
+            if unseen:
+                item["reviewed_at"] = stored["last_seen_updated_at"]
+                if stored.get("reviewed_state") == "open" and stored["state"] == "closed":
+                    item["change_summary"] = "Closed since last review"
+                elif stored.get("reviewed_state") == "closed" and stored["state"] == "open":
+                    item["change_summary"] = "Reopened since last review"
+                elif stored.get("reviewed_title") not in {None, stored["title"]}:
+                    item["change_summary"] = "Title changed since last review"
+                else:
+                    item["change_summary"] = "New activity"
             (changed if unseen else unchanged).append(item)
         changed.sort(key=lambda item: item["updated_at"], reverse=True)
         return {"revision": snapshot["revision"], "items": changed + unchanged}
@@ -194,8 +215,9 @@ class FollowingStore:
                     items.insert(0, item)
                 else:
                     item["last_seen_updated_at"] = items[index]["last_seen_updated_at"]
-                    if "kept_updated_at" in items[index]:
-                        item["kept_updated_at"] = items[index]["kept_updated_at"]
+                    for key in ("kept_updated_at", "reviewed_title", "reviewed_state"):
+                        if key in items[index]:
+                            item[key] = items[index][key]
                     if items[index] == item:
                         return self._present({"revision": current["revision"], "items": items})
                     items.pop(index)
@@ -229,8 +251,12 @@ class FollowingStore:
                 if update is None:
                     continue
                 update["last_seen_updated_at"] = item["last_seen_updated_at"]
-                if "kept_updated_at" in item:
-                    update["kept_updated_at"] = item["kept_updated_at"]
+                for key in ("kept_updated_at", "reviewed_title", "reviewed_state"):
+                    if key in item:
+                        update[key] = item[key]
+                if update["updated_at"] != item["updated_at"]:
+                    update.setdefault("reviewed_title", item["title"])
+                    update.setdefault("reviewed_state", item["state"])
                 if update != item:
                     items[index] = update
                     changed = True
@@ -272,6 +298,8 @@ class FollowingStore:
                         item.get("kept_updated_at") == updated_at):
                     item["last_seen_updated_at"] = updated_at
                     item.pop("kept_updated_at", None)
+                    item.pop("reviewed_title", None)
+                    item.pop("reviewed_state", None)
                     revision += 1
                     connection.execute(
                         "UPDATE following_issues SET revision = ?, items = ? WHERE login = ?",