@@ -67,31 +67,26 @@ def looks_tentative(component):
     summary = str(component.get('summary', ''))
     return component.get('status') == 'TENTATIVE' or 'TBD' in summary or summary.endswith("?")
 
-def custom_tentative_detector(component):
-    """
-    A custom function to determine if an event is tentative.
-    This can be passed to process_calendar_events to override the default logic.
+def process_calendar_events(calendar, start_date, end_date, is_tentative_fn=looks_tentative):
     """
-    summary = str(component.get('summary', ''))
-    # Add your custom logic here
-    return (component.get('status') == 'TENTATIVE' or
-            'TBD' in summary or
-            summary.endswith("?"))
+    Process events from a calendar and return a list of event periods.
 
-def process_calendar_events(calendar, busy, start_date, end_date, is_tentative_fn=None):
-    """
-    Process events from a calendar and add them to the FreeBusy component.
+    This function examines calendar components, filters them by date range,
+    determines if they are tentative based on the provided function,
+    and returns them as a list of vPeriod objects with FBTYPE property set.
 
     Args:
-        calendar: The input calendar to process
-        busy: The FreeBusy component to add events to
+        calendar: The input calendar object to process
         start_date: Start date for filtering events
         end_date: End date for filtering events
-        is_tentative_fn: Optional function to determine if an event is tentative
+        is_tentative_fn: Optional function to determine if an event is tentative,
+                        should accept a calendar component and return a boolean
+
+    Returns:
+        List of vPeriod objects with FBTYPE set to either
+        BUSY_TENTATIVE or BUSY_UNAVAILABLE
     """
-    if is_tentative_fn is None:
-        is_tentative_fn = looks_tentative
-
+    events = []
     for component in calendar.walk():
         if component.name == "VEVENT":
             dtstart = fixup_date(component.get('dtstart').dt)
@@ -105,7 +100,9 @@ vp.FBTYPE = icalendar.enums.FBTYPE.BUSY_TENTATIVE
                 else:
                     vp.FBTYPE = icalendar.enums.FBTYPE.BUSY_UNAVAILABLE
 
-                busy.add('freebusy', vp)
+                events.append(vp)
+
+    return events
 
 @app.route(f'/{str.lower(config.name)}.ics')
 def index():
@@ -128,8 +125,8 @@ busy.add('dtstart', start_date.astimezone(tz=utc))
     busy.add('dtend', end_date.astimezone(tz=utc))
 
     try:
-        # Process calendars from the config
         calendars_to_process = []
+        busy_periods = {}
 
         # For backward compatibility
         if config.calendar is not None and (config.calendar['file'] != "" or config.calendar['url'] != ""):
@@ -148,7 +145,25 @@ tentative_fn = lambda component: True
             else:
                 tentative_fn = looks_tentative
 
-            process_calendar_events(input_calendar, busy, start_date, end_date, is_tentative_fn=tentative_fn)
+            events = process_calendar_events(input_calendar, start_date, end_date, is_tentative_fn=tentative_fn)
+
+            # Process events considering tentative status
+            for event in events:
+                period_key = (event.dt[0], event.dt[1])
+
+                if period_key in busy_periods:
+                    existing_event = busy_periods[period_key]
+
+                    # If the existing event is tentative and the new one is not,
+                    # replace the existing event with the non-tentative one
+                    if (existing_event.FBTYPE == icalendar.enums.FBTYPE.BUSY_TENTATIVE and
+                        event.FBTYPE == icalendar.enums.FBTYPE.BUSY_UNAVAILABLE):
+                        busy_periods[period_key] = event
+                else:
+                    busy_periods[period_key] = event
+
+        for event in busy_periods.values():
+            busy.add('freebusy', event)
 
         output.add_component(busy)
         return output.to_ical(), {"Content-Type": "text/calendar"}