Improve topic management and add topic command

- Add topic command with list, skip, and max-count options
- Refactor _initialize_topics_table in store.py to handle roots and ancestors
- Display topic logs in reverse chronological order

devchat/_cli.py

@@ -19,7 +19,7 @@
 
 @click.group()
 def main():
-    """DevChat CLI: A command-line interface for the DevChat chatbot."""
+    """DevChat CLI: A command-line interface for DevChat."""
 
 
 @contextmanager
@@ -172,11 +172,12 @@ def prompt(content: Optional[str], parent: Optional[str], reference: Optional[Li
             sys.exit(os.EX_DATAERR)
 
 
+@main.command()
 @click.option('--skip', default=0, help='Skip number prompts before showing the prompt history.')
 @click.option('-n', '--max-count', default=100, help='Limit the number of commits to output.')
-@click.option('-t', '--topic', default=None,
+@click.option('-t', '--topic', 'topic_root', default=None,
               help='Hash of the root prompt of the topic to select prompts from.')
-def log(skip, max_count, topic):
+def log(skip, max_count, topic_root):
     """
     Show the prompt history.
     """
@@ -190,11 +191,41 @@ def log(skip, max_count, topic):
         click.echo(f"Error: Invalid LLM in configuration '{provider}'", err=True)
         sys.exit(os.EX_DATAERR)
 
-    recent_prompts = store.select_prompts(skip, skip + max_count, topic)
+    recent_prompts = store.select_prompts(skip, skip + max_count, topic_root)
     logs = []
     for record in recent_prompts:
         try:
             logs.append(record.shortlog())
         except Exception:
             continue
     click.echo(json.dumps(logs, indent=2))
+
+
+@main.command()
+@click.option('--list', '-l', 'list_topics', is_flag=True,
+              help='List topics in reverse chronological order.')
+@click.option('--skip', default=0, help='Skip number of topics before showing the list.')
+@click.option('-n', '--max-count', default=100, help='Limit the number of topics to output.')
+def topic(list_topics: bool, skip: int, max_count: int):
+    """
+    Manage topics.
+    """
+    config, chat_dir = init_dir()
+    provider = config.get('provider')
+    if provider == 'OpenAI':
+        openai_config = OpenAIChatConfig(model=config['model'], **config['OpenAI'])
+        chat = OpenAIChat(openai_config)
+        store = Store(chat_dir, chat)
+    else:
+        click.echo(f"Error: Invalid LLM in configuration '{provider}'", err=True)
+        sys.exit(os.EX_DATAERR)
+
+    if list_topics:
+        topics = store.select_topics(skip, skip + max_count)
+        topic_logs = []
+        for topic_data in topics:
+            try:
+                topic_logs.append(topic_data['root_prompt'].shortlog())
+            except Exception:
+                continue
+        click.echo(json.dumps(topic_logs, indent=2))

devchat/store.py

@@ -45,8 +45,11 @@ def __init__(self, store_dir: str, chat: Chat):
     def _initialize_topics_table(self):
         roots = [node for node in self._graph.nodes() if self._graph.out_degree(node) == 0]
         for root in roots:
-            latest_time = max(self._graph.nodes[node]['timestamp'] for
-                              node in nx.ancestors(self._graph, root))
+            ancestors = nx.ancestors(self._graph, root)
+            if not ancestors:
+                latest_time = self._graph.nodes[root]['timestamp']
+            else:
+                latest_time = max(self._graph.nodes[node]['timestamp'] for node in ancestors)
             self._topics_table.insert({
                 'root': root,
                 'latest_time': latest_time,