feat(ai): generate covers without new titles

app/ai.py

@@ -349,6 +349,15 @@ def _has_generated_cover(task):
     return bool(str(getattr(task, "new_cover_path", "") or "").strip())
 
 
+def cover_title_context(task):
+    """Return the title used to describe a cover without changing task results."""
+
+    new_title = str(getattr(task, "new_title", "") or "").strip()
+    if new_title:
+        return new_title
+    return str(getattr(task, "old_title", "") or "").strip()
+
+
 def generation_needs(task, generate_cover=False, generate_mode=None):
     """Return which AI components still need generation for this task."""
 
@@ -370,7 +379,7 @@ def generation_needs(task, generate_cover=False, generate_mode=None):
     needs_cover = False
     if appconfig.generate_mode_includes_cover(mode) and not _has_generated_cover(task):
         if mode == "cover":
-            needs_cover = has_title
+            needs_cover = bool(cover_title_context(task))
         else:
             needs_cover = has_title or needs_title
     return {"title": needs_title, "cover": needs_cover}
@@ -587,9 +596,29 @@ def generate_batch(tasks, prompts, ai_cfg=None, on_progress=None, should_stop=No
 
     for task in eligible:
         task_id = getattr(task, "id", None)
-        if task_id not in title_results and _has_generated_title(task):
-            title_results[task_id] = str(getattr(task, "new_title") or "")
-            _emit_generation_event(on_event, task, "title", "title_submit", "skipped", detail="已有标题")
+        if task_id in title_results:
+            continue
+        if generate_mode == "cover":
+            title_context = cover_title_context(task)
+        elif _has_generated_title(task):
+            title_context = str(getattr(task, "new_title") or "")
+        else:
+            title_context = ""
+        if not title_context:
+            continue
+        title_results[task_id] = title_context
+        if _has_generated_title(task):
+            detail = "已有标题"
+        else:
+            detail = "没有新标题，本轮使用旧标题作为封面参考"
+        _emit_generation_event(
+            on_event,
+            task,
+            "title",
+            "title_submit",
+            "skipped",
+            detail=detail,
+        )
 
     cover_tasks = [
         task for task in cover_candidates
@@ -627,19 +656,21 @@ def generate_batch(tasks, prompts, ai_cfg=None, on_progress=None, should_stop=No
             level="warning",
         )
 
-    def persist_cover_success(task, new_title, new_cover_path):
+    def persist_cover_success(task, title_context, new_cover_path):
         set_step(task, "db_write")
         _emit_generation_event(on_event, task, "cover", "db_write", "start")
-        db.set_generated(task.id, new_title, new_cover_path, path=db_path)
+        db.set_generated_cover(task.id, new_cover_path, path=db_path)
         summary["cover_done"] += 1
         summary["generated_done"] += 1
+        needs_title = needs_by_task.get(getattr(task, "id", None), {}).get("title")
+        persisted_title = title_context if needs_title else getattr(task, "new_title", None)
         if on_task_update is not None:
             on_task_update(
                 task.id,
                 {
                     "stage": "generated",
                     "status": "success",
-                    "new_title": new_title,
+                    "new_title": persisted_title,
                     "new_cover_path": new_cover_path,
                 },
             )