Calendar implementation

lib/services/google_calendar_service.dart

@@ -0,0 +1,154 @@
+import 'package:http/http.dart' as http;
+
+class CalendarEvent {
+  final String? summary;
+  final String? description;
+  final String? location;
+  final DateTime? startTime;
+  final DateTime? endTime;
+  final bool isAllDay;
+
+  CalendarEvent({
+    this.summary,
+    this.description,
+    this.location,
+    this.startTime,
+    this.endTime,
+    this.isAllDay = false,
+  });
+}
+
+class GoogleCalendarService {
+  static const String calendarId =
+      'b9c267252d5be63d5cdc880be499885a88421eefd0e34e1392890daba0d8471e@group.calendar.google.com';
+
+  final http.Client _httpClient = http.Client();
+
+  Future<List<CalendarEvent>> getEvents({
+    DateTime? startDate,
+    DateTime? endDate,
+  }) async {
+    try {
+      // Use the public iCal feed URL
+      final url = Uri.parse(
+          'https://calendar.google.com/calendar/ical/$calendarId/public/basic.ics');
+
+      final response = await _httpClient.get(url);
+
+      if (response.statusCode == 200) {
+        return _parseICalendar(response.body);
+      } else {
+        throw Exception('Failed to load calendar: ${response.statusCode}');
+      }
+    } catch (e) {
+      throw Exception('Error fetching events: $e');
+    }
+  }
+
+  List<CalendarEvent> _parseICalendar(String icalData) {
+    final events = <CalendarEvent>[];
+    final lines = icalData.split('\n');
+
+    String? summary;
+    String? description;
+    String? location;
+    DateTime? startTime;
+    DateTime? endTime;
+    bool isAllDay = false;
+
+    for (var i = 0; i < lines.length; i++) {
+      var line = lines[i].trim();
+
+      // Handle line continuations
+      while (i + 1 < lines.length && lines[i + 1].startsWith(' ')) {
+        i++;
+        line += lines[i].trim();
+      }
+
+      if (line.startsWith('BEGIN:VEVENT')) {
+        summary = null;
+        description = null;
+        location = null;
+        startTime = null;
+        endTime = null;
+        isAllDay = false;
+      } else if (line.startsWith('SUMMARY:')) {
+        summary = _unescapeText(line.substring(8));
+      } else if (line.startsWith('DESCRIPTION:')) {
+        description = _unescapeText(line.substring(12));
+      } else if (line.startsWith('LOCATION:')) {
+        location = _unescapeText(line.substring(9));
+      } else if (line.startsWith('DTSTART')) {
+        final dateStr = line.split(':')[1];
+        if (line.contains('VALUE=DATE')) {
+          isAllDay = true;
+          startTime = _parseDate(dateStr);
+        } else {
+          startTime = _parseDateTime(dateStr);
+        }
+      } else if (line.startsWith('DTEND')) {
+        final dateStr = line.split(':')[1];
+        if (line.contains('VALUE=DATE')) {
+          endTime = _parseDate(dateStr);
+        } else {
+          endTime = _parseDateTime(dateStr);
+        }
+      } else if (line.startsWith('END:VEVENT')) {
+        events.add(CalendarEvent(
+          summary: summary,
+          description: description,
+          location: location,
+          startTime: startTime,
+          endTime: endTime,
+          isAllDay: isAllDay,
+        ));
+      }
+    }
+
+    return events;
+  }
+
+  String _unescapeText(String text) {
+    return text
+        .replaceAll('\\n', '\n')
+        .replaceAll('\\,', ',')
+        .replaceAll('\\;', ';')
+        .replaceAll('\\\\', '\\');
+  }
+
+  DateTime? _parseDate(String dateStr) {
+    try {
+      // Format: YYYYMMDD
+      final year = int.parse(dateStr.substring(0, 4));
+      final month = int.parse(dateStr.substring(4, 6));
+      final day = int.parse(dateStr.substring(6, 8));
+      return DateTime(year, month, day);
+    } catch (e) {
+      return null;
+    }
+  }
+
+  DateTime? _parseDateTime(String dateStr) {
+    try {
+      // Format: YYYYMMDDTHHMMSSZ or YYYYMMDDTHHMMSS
+      final year = int.parse(dateStr.substring(0, 4));
+      final month = int.parse(dateStr.substring(4, 6));
+      final day = int.parse(dateStr.substring(6, 8));
+      final hour = int.parse(dateStr.substring(9, 11));
+      final minute = int.parse(dateStr.substring(11, 13));
+      final second = int.parse(dateStr.substring(13, 15));
+
+      if (dateStr.endsWith('Z')) {
+        return DateTime.utc(year, month, day, hour, minute, second);
+      } else {
+        return DateTime(year, month, day, hour, minute, second);
+      }
+    } catch (e) {
+      return null;
+    }
+  }
+
+  void dispose() {
+    _httpClient.close();
+  }
+}