created CalendarParser class

remindme_caldav.py

@@ -1,3 +1,4 @@
+from pathlib import Path
 from icalendar import Calendar, Event
 import toml, argparse, os, sys, hashlib, json, pytz, glob, os, time
 from dateutil.relativedelta import relativedelta
@@ -9,38 +10,49 @@ from watchdog.events import FileSystemEventHandler
 import email_alert, xmpp_alert
 from pprint import pprint
 import humanfriendly
+from pathlib import Path
+import argparse
+import textwrap
+import logging
 
-# Parse args
-parser = argparse.ArgumentParser(description="A simple calendar alerting daemon written in Python")
-parser.add_argument('--config', type=str, help='Path to config file. Must be .toml')
-args = parser.parse_args()
+def setup_logger(loglevel):
+    """Setup basic logging."""
+    loglevel = getattr(logging, loglevel.upper(), None)
     
-if not args.config:
-    print("Error: No config file provided.")
+    if not isinstance(loglevel, int):
+        raise ValueError('Invalid log level: %s' % loglevel)
+        
+    logging.basicConfig(filename='app.log', filemode='w', format='%(name)s - %(levelname)s - %(message)s')
+    logger = logging.getLogger()
+    logger.setLevel(loglevel)
+
+def parse_args():
+    """Parse command line arguments."""
+    parser = argparse.ArgumentParser(description="A simple calendar alerting daemon written in Python")
+    parser.add_argument('--config', type=str, help='Path to config file. Must be .toml')
+    parser.add_argument('--loglevel', choices=['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'], default='INFO', help='Set the logging level')
+    args = parser.parse_args()
+    if args.config is None:
+        raise ValueError("No config file provided")
+    return args
+
+def read_file(filename):                                       
+    try:                                                       
+        return Path(filename).read_text()                      
+    except FileNotFoundError as e:                             
+        print(f"Error: The specified file does not exist. {e}")
         sys.exit(1)  # Exit with error code                    
-elif not os.path.isfile(args.config):
-    print("Error: The specified config file does not exist.")
-    sys.exit(1)  # Exit with error code
-else:
-    print("Config file path: ", args.config)
                                                                
-# Get config
-try:
-    with open(args.config, 'r') as f:
-        config = toml.load(f)
-except Exception as e:
+def parse_toml(content):                                       
+    try:                                                       
+        return toml.loads(content)                             
+    except Exception as e:                                     
         print("Error: Failed to parse TOML file.")             
         print(e)                                               
         sys.exit(1)  # Exit with error code                    
 
-cal_dir = config["app"]["calendar_dir"]
-# Check if the path is a directory
-if not os.path.isdir(cal_dir):
-    print("The provided path to .ics files does not exist: '{}'".format(cal_dir))
-    exit(1)
-
-# Get all .ics files from your directory
-files = glob.glob(os.path.join(cal_dir, '*.ics'))
+def calculate_event_hash(event):
+    return hashlib.md5(json.dumps(event, sort_keys=True, cls=DateTimeEncoder).encode()).hexdigest()
 
 class DateTimeEncoder(json.JSONEncoder):
     def default(self, o):
@@ -53,29 +65,11 @@ class FileChangeHandler(FileSystemEventHandler):
     `FileChangeHandler` is a custom event handler for the
     `watchdog.observers.Observer` class that handles file system events such as
     file modifications, deletions and creations.
-
-    It inherits from `watchdog.events.FileSystemEventHandler` providing methods
-    to handle these events: `on_modified`, `on_deleted`, and `on_created`. Each
-    method is overridden for specific functionality when a file system event
-    occurs.
-
-    The class also includes a method `calculate_event_hash` that generates an
-    MD5 hash for each event dictionary based on its contents. This is used to
-    track changes in the events and determine if they have been modified or
-    deleted.
-    
-    For example, when a file is modified:
-    - It reads the content of the file, parses it into an event dictionary
-      using `calendar_parser`.
-    - Calculates the hash for the event and checks if there's already an
-      existing event with the same UID in `event_list`.
-    - If there is one, it compares the new hash with the old hash. If they
-      differ, it prints that the event has been modified or deleted. Otherwise,
-      it prints that the event hasn't been modified.
-    
-    For file deletion and creation, similar operations are performed but
-    without comparison of hashes.
     """
+    def __init__(self, event_list):
+        self.calendar_parser = CalendarParser()  # Create an instance of CalendarParser
+        self.event_list = event_list   
+
     def on_modified(self, event):
         print(f"File modified: {event.src_path}")
         if not event.is_directory:    
@@ -87,7 +81,7 @@ class FileChangeHandler(FileSystemEventHandler):
                 return
             
             try:
-                event_dict = calendar_parser(cal_str)
+                event_dict = self.calendar_parser.parse_calendar(cal_str)  # Use the instance to call parse_calendar method
             except Exception as i:
                 print("Failed to parse calendar event at: {}.\n Error:\n{}".format(event.src_path,i))
                 return 
@@ -113,7 +107,7 @@ class FileChangeHandler(FileSystemEventHandler):
                 return
                 
             try:
-                event_dict = calendar_parser(cal_str)
+                event_dict = self.calendar_parser.parse_calendar(cal_str)  # Use the instance to call parse_calendar method
             except Exception as i:
                 print("Failed to parse calendar event at: {}.\n Error:\n{}".format(event.src_path,i))
                 return 
@@ -122,81 +116,55 @@ class FileChangeHandler(FileSystemEventHandler):
     
     def handle_modified(self, old_event, event_dict, remove=False):
         if not remove:
-            for i, old_event in enumerate(event_list):
+            for i, old_event in enumerate(self.event_list):
                 if old_event["uid"] == event_dict["uid"]:  
                     old_hash = old_event["hash"]
                     
-                    new_hash = self.calculate_event_hash(event_dict)
+                    new_hash = calculate_event_hash(event_dict)
                     if new_hash != old_hash:    
                         print("Event with UID {} has been modified or deleted".format(old_event["uid"]))
                         
-                        event_list[i] = event_dict
+                        self.event_list[i] = event_dict
                     else:   
                         print("Event with UID {} hasn't been modified".format(old_event["uid"]))
                     
                     break
             else:    
-                event_list.append(event_dict)
+                self.event_list.append(event_dict)
         else:   # If remove is True, remove the event from the list
-            for i, old_event in enumerate(event_list):
+            for i, old_event in enumerate(self.event_list):
                 if old_event["uid"] == event_dict["uid"]:   
                     print("Event with UID {} has been deleted".format(old_event["uid"]))
                     
-                    del event_list[i]
+                    del self.event_list[i]
                     break
 
-    def calculate_event_hash(self, event):
-        return hashlib.md5(json.dumps(event, sort_keys=True, cls=DateTimeEncoder).encode()).hexdigest()
 
-def generate_recurring_event_dates(dtstart, rrule):
-    """
-    Generate recurring event dates based on a start date and an RRULE.
-
-    This function takes in a start date (`dtstart`) and an RRULE (`rrule`),
-    which is used to generate future dates according to the rules specified by
-    the RRULE.
-
-    If no count rule is present, it generates a date array from `dtstart` to
-    the current datetime, then adds an arbitrary number of dates into the
-    future (here it's 10). This is done because generating a date array using
-    the rrulestr function without a count rule will return a very large number
-    of elements.
-
-    The function returns a dictionary containing information about the
-    recurring event:
-      - `recur_dates`: A list of future dates generated by the RRULE.
-      - `infinite_recur`: Boolean indicating whether the recurrence is infinite.
-      - `recur_freq`: The frequency of the recurrence (e.g., 'DAILY').
-      - `recur_interval`: The interval between each occurrence of the event.
-      - `n_recur_dates_left`: The number of future dates left.
-
-    Parameters:
-        dtstart (datetime): The start date of the recurring event.
-        rrule (rrule): The RRULE object specifying the recurrence rules.
-
-    Returns:
-        dict: A dictionary containing information about the recurring event
-        dates, frequency, interval and count.
-    """
-    recur_info = {
+class RecurringEventGenerator:
+    def __init__(self, dtstart, rrule):
+        self.dtstart = dtstart
+        self.rrule = rrule
+        self.recur_info = {
             "recur_dates": [dtstart], 
             "infinite_recur": False,
             "recur_freq": None,
             "recur_interval": None,
             "n_recur_dates_left": None
         }
-    if rrule is None:
-        return recur_info
-    rule_str = "RRULE:{}".format(rrule.to_ical().decode('utf-8'))
-    start_date = dtstart
+        
+    def generate(self):
+        if self.rrule is None:
+            return self.recur_info
+            
+        rule_str = "RRULE:{}".format(self.rrule.to_ical().decode('utf-8'))
+        start_date = self.dtstart
         infinite_recur = False
-    freq = rrule.get('FREQ')[0]
-    count = rrule.get("COUNT")
-    interval = rrule.get('INTERVAL')[0]
+        freq = self.rrule.get('FREQ')[0]
+        count = self.rrule.get("COUNT")
+        interval = self.rrule.get('INTERVAL')[0]
         current_date = dt.datetime.now().replace(tzinfo=pytz.UTC)
         
-    if count is None:# or until is not None:
-            
+        if count is None:
             delta = None
             
             if freq == "DAILY":
@@ -223,74 +191,36 @@ def generate_recurring_event_dates(dtstart, rrule):
         recur_dates = [i for i in dates if i >= current_date]
         n_recur = "inf" if infinite_recur is True else len(recur_dates) 
         
-    recur_info["recur_dates"] = recur_dates
-    recur_info["infinite_recur"] = infinite_recur
-    recur_info["recur_freq"] = freq
-    recur_info["recur_interval"] = interval
-    recur_info["n_recur_dates_left"] = n_recur
-    return recur_info
+        self.recur_info["recur_dates"] = recur_dates
+        self.recur_info["infinite_recur"] = infinite_recur
+        self.recur_info["recur_freq"] = freq
+        self.recur_info["recur_interval"] = interval
+        self.recur_info["n_recur_dates_left"] = n_recur
         
-def calendar_parser(cal_str):
+        return self.recur_info
+
+class CalendarParser:
+    def parse_calendar(self, cal_str):
         # Parse the calendar
-    cal = Calendar.from_ical(cal_str)
+        cal = self.parse_icalendar(cal_str)
         
         # Iterate over each event in the calendar
         for event in cal.walk('vevent'):
+            event_dict = self.process_event(event)
+            dtstart = self.dtstart_to_datetime(event_dict["dtstart"].dt)
             
-        event_info = {
-                "uid": None,
-                "dtstart": "",
-                "exdate": [],
-                "summary": None,
-                "description": None,
-                "location": None,
-                "rrule": None
-        }
-        # Catch errors for missing components
-        for info in event_info:
-            try:
-                event_info[info] = event[info]
-            except Exception:
-                pass
+            generator = RecurringEventGenerator(dtstart, event_dict["rrule"])
+            recur_info = generator.generate() 
+            event_dates = self.remove_exdates(event_dict["exdate"], recur_info["recur_dates"])
 
-        uid = str(event_info["uid"])
-        dtstart = event_info["dtstart"].dt
-        exdates = event_info["exdate"]
-        if exdates is not []:
-            if isinstance(exdates, list):
-                exdates = [i.dts.dt.replace(tzinfo=pytz.UTC) for i in exdates]
-            else:
-                exdates = [exdates.dts[0].dt.replace(tzinfo=pytz.UTC)]
-        summary = event["summary"]
-        description = event_info["description"]
-        location = event_info["location"]
-        rrule = event_info["rrule"]
-                             
-        # Ensure dates are always as datetime
-        if isinstance(dtstart, dt.datetime): 
-            dtstart = dtstart.replace(tzinfo=pytz.UTC)
-        else:
-            dtstart = dt.datetime.combine(dtstart, dt.time.min).replace(tzinfo=pytz.UTC)
-         
-        # Get recurring events if they exist
-        recur_info = generate_recurring_event_dates(dtstart, rrule)
-        event_dates = recur_info["recur_dates"]
-
-        # Remove exdates
-        event_dates = [i for i in event_dates if i not in exdates]
-    
-        valarms = []
-        for subcomponent in event.walk("valarm"):
-            valarm = Event.from_ical(subcomponent.to_ical())
-            timedelta = valarm["trigger"].dt
-            valarms.append(timedelta)
+            valarms = self.process_valarm(event)
             
             event_dict = {
-                "uid": uid, 
+                "uid": str(event_dict["uid"]), 
                 "dtstart": dtstart,
-                "summary": summary,
-                "description": description,
-                "location": location,
+                "summary": event_dict["summary"],
+                "description": event_dict["description"],
+                "location": event_dict["location"],
                 "event_dates": event_dates,
                 "recur_info": "Recur freq: {}, Recur interval: {}, N dates left: {}".format(
                     recur_info["recur_freq"], 
@@ -300,23 +230,75 @@ def calendar_parser(cal_str):
                 "valarms": valarms,
                 "alert_history": []
             }
-
-        handler = FileChangeHandler()  # Create an instance of the FileChangeHandler class
-        new_hash = handler.calculate_event_hash(event_dict)  # Calculate the hash of the event dictionary
+            new_hash = calculate_event_hash(event_dict)  # Calculate the hash of the event dictionary
             event_dict["hash"] = new_hash  # Store the hash in the event dictionary
             return event_dict
     
+    def parse_icalendar(self, cal_str):
+            return Calendar.from_ical(cal_str)
+            
+    def process_event(self, event):
+        # Catch errors for missing components
+        event_info = {
+                 "uid": None,
+                 "dtstart": "",
+                 "exdate": [],
+                 "summary": None,
+                 "description": None,
+                 "location": None,
+                 "rrule": None
+         }
+         
+        for info in event_info:
+            try:
+                event_info[info] = event[info]
+            except Exception:
+                pass
+            
+        return event_info
+    
+    def dtstart_to_datetime(self, dtstart):
+        # Ensure dates are always as datetime
+        if isinstance(dtstart, dt.datetime): 
+            return dtstart.replace(tzinfo=pytz.UTC)
+        else:
+            return dt.datetime.combine(dtstart, dt.time.min).replace(tzinfo=pytz.UTC)
+
+    def remove_exdates(self, exdates, recur_dates):
+        if exdates != []:
+            if isinstance(exdates, list):
+                exdates = [i.dts[0].dt.replace(tzinfo=pytz.UTC) for i in exdates]
+            else:
+                exdates = [exdates.dts[0].dt.replace(tzinfo=pytz.UTC)]
+            return [i for i in recur_dates if i not in exdates]
+        else: 
+            return recur_dates
+
+    def process_valarm(self, event):
+        valarms = []
+        for subcomponent in event.walk("valarm"):
+            valarm = Event.from_ical(subcomponent.to_ical())
+            timedelta = valarm["trigger"].dt
+            valarms.append(timedelta)
+        return valarms
+
 def get_next_alert(event, current_time):
+    """
+    This function returns the next alert that should be processed based on the current time.
+    """
     event_dates = event["event_dates"]
     valarm_deltas = event["valarms"]
-    if event_dates == [] or current_time > event_dates[-1]:
+    if event_dates == [] or event_dates is None or current_time > event_dates[-1]:
         return None, None
     next_event = [i for i in event_dates if i >= current_time][0]
     next_alert_list = [next_event + i for i in valarm_deltas]
     next_alert = min(next_alert_list)
     return next_alert - dt.timedelta(seconds=5), next_event
 
-def process_alert(current_time, next_alert, event):
+def process_alert(current_time, next_alert, next_event, event, config):
+    """
+    This function processes a given alert and passes it to a messaging client.
+    """
     if current_time >= next_alert and next_alert < next_alert + dt.timedelta(seconds=15):
         if len(event["alert_history"]) == 0:
             print("First alert for '{}' detected".format(event["summary"]))
@@ -333,19 +315,36 @@ def process_alert(current_time, next_alert, event):
             f.write(str(event))  # write expects a str not dict
         return
 
-# Create initial event_list using calendar_parser
-event_list = []  # List to hold dictionaries for each event
-for file in files:
+def main():
+    # Parse args and config
+    args = parse_args()
+    content = read_file(args.config)
+    config = parse_toml(content)
+   
+    # Get calendar dir
+    cal_dir = Path(config["app"]["calendar_dir"])
+    if not cal_dir.is_dir():                                                  
+        print(f"The provided path to .ics files does not exist: '{cal_dir}'") 
+        sys.exit(1)  # Exit with error code                                   
+
+    #Parse calendar events
+    calendar_parser = CalendarParser()
+    files = list(cal_dir.glob('*.ics'))                        
+    event_list = []  # List to hold dictionaries for each event
+    for file in files:
         with open(file, 'r') as f:
             cal_str = f.read()
-    event_dict = calendar_parser(cal_str)
+        event_dict = calendar_parser.parse_calendar(cal_str)
         event_list.append(event_dict)
 
-observer = Observer()
-handler = FileChangeHandler()
-observer.schedule(handler, cal_dir, recursive=True)
-observer.start()
-try:
+    #Start file handler to detect changes to calendar dir
+    observer = Observer()
+    handler = FileChangeHandler(event_list)  # Pass event_list here
+    observer.schedule(handler, cal_dir, recursive=True)
+    observer.start()
+
+    #Start main loop
+    try:
         while True:
             with open("status", 'w') as f:
                 #Refresh the status file
@@ -358,13 +357,24 @@ try:
                 event_delta = next_alert-current_time
                 total_seconds = event_delta.total_seconds()
                 human_readable_time = humanfriendly.format_timespan(total_seconds)
-            monitor_status = "Current time: {}\nMonitoring: {}\nEvent date: {}\nRecur Dates: {}\nNext alert on: {} in {}\nRecur info: {}\nAlert history: {}\n".format(current_time, event["summary"], next_event, [str(i) for i in event["event_dates"]], next_alert, human_readable_time, event["recur_info"], event["alert_history"])
+                monitor_status = f"""\
+                    Current time: {current_time}
+                    Monitoring: {event["summary"]}
+                    Event date: {next_event}
+                    Recur Dates: {[str(i) for i in event["event_dates"]]}
+                    Next alert on: {next_alert} in {human_readable_time}
+                    Recur info: {event["recur_info"]}
+                    Alert history: {event["alert_history"]}\n"""
+                monitor_status = textwrap.dedent(monitor_status)
                 with open("status", 'a') as f:
                     # Write the output to the file
                     f.write(monitor_status)
                     f.write("\n")
-            process_alert(current_time, next_alert, event)
+                process_alert(current_time, next_alert, next_event, event, config)
             time.sleep(1)
-except KeyboardInterrupt:
+    except KeyboardInterrupt:
         observer.stop()
-observer.join()
+        observer.join()
+
+if __name__ == "__main__":
+    main()