Table works

ums/management/main.py

@@ -16,6 +16,8 @@ from fastapi import FastAPI, Request
 from fastapi.responses import HTMLResponse
 from fastapi.templating import Jinja2Templates
 
+from jinja2.runtime import Undefined as JinjaUndefined
+
 from ums.management.interface import Interface
 from ums.management.db import DB
 
@@ -23,6 +25,8 @@ from ums.utils import AgentMessage, RiddleData, RiddleDataType, RiddleSolution,
 
 class WebMain():
 
+	_TIME_FORMAT = "%H:%M:%S %d.%m.%Y"
+
 	def __init__(self):
 		self._init_app()
 		self._init_templates()
@@ -47,8 +51,17 @@ class WebMain():
 			directory=TEMPLATE_PATH,
 			auto_reload=True
 		)
-		self.template.env.globals["timestamp2date"] = lambda t: \
-			datetime.fromtimestamp(t).strftime("%H:%M:%S %d.%m.%Y")
+		
+		def timestamp2date(t:int|JinjaUndefined) -> str:
+			return "" if isinstance(t, JinjaUndefined) \
+				else datetime.fromtimestamp(t).strftime(self._TIME_FORMAT)
+		self.template.env.globals["timestamp2date"] = timestamp2date
+
+		def date2timestamp(d:str|JinjaUndefined) -> int|str:
+			return "" if isinstance(d, JinjaUndefined) \
+				else int(datetime.strptime(d, self._TIME_FORMAT).timestamp())
+		self.template.env.globals["date2timestamp"] = date2timestamp
+
 
 	def _add_routers(self):
 		interface_router = Interface(self.template, self.db)