From ab4d12d21473ee2929c0d98771cbda63b91badf2 Mon Sep 17 00:00:00 2001
From: Richard Chien <richardchienthebest@gmail.com>
Date: Thu, 21 Feb 2019 21:57:05 +0800
Subject: [PATCH] Add argfilter type "controllers"

---
 nonebot/command/argfilter/controllers.py | 34 ++++++++++++++++++++++++
 nonebot/default_config.py                |  1 +
 2 files changed, 35 insertions(+)
 create mode 100644 nonebot/command/argfilter/controllers.py

diff --git a/nonebot/command/argfilter/controllers.py b/nonebot/command/argfilter/controllers.py
new file mode 100644
index 00000000..b8b57173
--- /dev/null
+++ b/nonebot/command/argfilter/controllers.py
@@ -0,0 +1,34 @@
+import re
+
+from nonebot import CommandSession
+from nonebot.helpers import render_expression
+
+
+def handle_cancellation(session: CommandSession):
+    """
+    If the input is a string of cancellation word, finish the command session.
+    """
+
+    def control(value):
+        if _is_cancellation(value):
+            session.finish(render_expression(
+                session.bot.config.SESSION_CANCEL_EXPRESSION))
+        return value
+
+    return control
+
+
+async def _is_cancellation(sentence: str) -> bool:
+    for kw in ('算', '别', '不', '停', '取消'):
+        if kw in sentence:
+            # a keyword matches
+            break
+    else:
+        # no keyword matches
+        return False
+
+    if re.match(r'^那?[算别不停]\w{0,3}了?吧?$', sentence) or \
+            re.match(r'^那?(?:[给帮]我)?取消了?吧?$', sentence):
+        return True
+
+    return False
diff --git a/nonebot/default_config.py b/nonebot/default_config.py
index 19cb9432..86e1b9e2 100644
--- a/nonebot/default_config.py
+++ b/nonebot/default_config.py
@@ -33,6 +33,7 @@ COMMAND_SEP: Iterable[Union[str, Pattern]] = {'/', '.'}
 SESSION_EXPIRE_TIMEOUT: Optional[timedelta] = timedelta(minutes=5)
 SESSION_RUN_TIMEOUT: Optional[timedelta] = None
 SESSION_RUNNING_EXPRESSION: Expression_T = '您有命令正在执行，请稍后再试'
+SESSION_CANCEL_EXPRESSION = '好的'
 SHORT_MESSAGE_MAX_LENGTH: int = 50
 DEFAULT_VALIDATION_FAILURE_EXPRESSION: Expression_T = '您的输入不符合要求，请重新输入'