add lack of data message

streamlit_src/controllers/admin_controller.py

@@ -30,8 +30,11 @@ class AdminController(UserController):
         switch = self._view.show_admin_pages()
 
         if switch == "Display Predictions":
-            self._show_current_data()
-            self._display_plots()
+            if not self._is_current_data_available():
+                self._view.data_not_available()
+            else:
+                self._show_current_data()
+                self._display_plots()
 
         elif switch == "Make Predictions":
             self._make_custom_predictions()

streamlit_src/controllers/user_controller.py

@@ -7,7 +7,7 @@ import os
 import pandas as pd
 import random
 import json
-from datetime import date, timedelta
+from datetime import date, datetime, timedelta
 import plotly.graph_objects as go
 
 
@@ -48,16 +48,37 @@ class UserController:
         """
         Shows the main page of the user interface.
         """
-        self._show_current_data()
-
         self._view.two_columns_layout(0.7, self._raise_awareness, self._quiz)
 
-        self._display_plots()
+        if not self._is_current_data_available():
+            self._view.data_not_available()
+        else:
+            self._show_current_data()
+
+            self._display_plots()
 
-        self._display_compare_who()
+            self._display_compare_who()
 
         self._display_sources()
 
+    def _is_current_data_available(self) -> bool:
+        """
+        Checks if the current data is available.
+
+        The current data is not available from 14:00 to 15:15.
+        This is because the API is queried every 15 minutes, and the
+        data is not available for a short period of time before and after
+        the new data is fetched.
+
+        :return: True if the current data is available, False otherwise.
+        """
+        current_time = datetime.now().time()
+        start_time = current_time.replace(hour=0, minute=0, second=0)
+        end_time = current_time.replace(hour=4, minute=15, second=0)
+        if start_time <= current_time <= end_time:
+            return False
+        return True
+
     def _display_sources(self) -> None:
         """
         Displays the sources on the main page of the user interface.
@@ -86,7 +107,6 @@ class UserController:
         Displays the plots on the main page of the user interface.
         """
         plot_type = self._view.view_option_selection(["Line Plot", "Gauge Plot"])
-
         if plot_type == "Line Plot":
             line_fig = self._prepare_line_plot()
             self._view.display_predictions_lineplot(line_fig)

streamlit_src/views/user_view.py

@@ -23,6 +23,19 @@ class UserView:
         st.sidebar.markdown("### Current Pollutant Concentrations and WHO Guidelines")
         st.sidebar.dataframe(merged_data_df, hide_index=True)
 
+    def data_not_available(self) -> None:
+        """
+        Show an error message indicating that data is not available.
+
+        This is shown when the current time is between 00:00 and 04:15, when the measurements aren't accurate enough to produce a prediction.
+        The data will be automatically updated at 04:15 with the prediction for the next three days.
+        """
+        st.markdown("### Data Not Available")
+
+        error_message = "🚨 Between 00:00 and 04:15, the measurements aren't accurate enough to produce a prediction or have an informative summary for today's air pollution. The data will be automatically updated at 04:15 with the prediction for the next three days."
+
+        self.two_columns_layout(0.7, lambda: st.error(error_message), lambda: None)
+
     def success(self, message: str) -> None:
         """
         Show a success message.