New

lib/services/ics_service.dart

@@ -0,0 +1,69 @@
+import 'dart:io';
+import 'package:flutter/foundation.dart';
+import 'package:icalendar_parser/icalendar_parser.dart';
+import 'package:path_provider/path_provider.dart';
+import 'package:open_filex/open_filex.dart';
+import 'package:universal_html/html.dart' as html;
+import 'package:intl/intl.dart';
+
+import '../models/cycle_entry.dart';
+
+class IcsService {
+  static Future<void> generateCycleCalendar(List<CycleEntry> entries) async {
+    final iCalendar = ICalendar(
+      properties: {
+        'prodid': '-//Christian Period Tracker//NONSGML v1.0//EN',
+        'version': '2.0',
+        'calscale': 'GREGORIAN',
+        'x-wr-calname': 'Cycle Tracking',
+        'x-wr-timezone': DateTime.now().timeZoneName,
+      },
+      components: [],
+    );
+
+    // Sort entries by date to ensure proper calendar order
+    entries.sort((a, b) => a.date.compareTo(b.date));
+
+    for (var entry in entries) {
+      if (entry.isPeriodDay) {
+        final date = entry.date;
+        final formattedDate = DateFormat('yyyyMMdd').format(date);
+        final uid = '${date.year}${date.month}${date.day}-${entry.id}@christianperiodtracker.app';
+
+        iCalendar.components.add(
+          CalendarEvent(
+            properties: {
+              'uid': uid,
+              'dtstamp': IcsDateTime(dt: DateTime.now()),
+              'dtstart': IcsDateTime(dt: date, isUtc: false, date: true), // All-day event
+              'dtend': IcsDateTime(dt: date.add(const Duration(days: 1)), isUtc: false, date: true), // End on next day for all-day
+              'summary': 'Period Day',
+              'description': 'Period tracking for ${DateFormat.yMMMd().format(date)}',
+            },
+          ),
+        );
+      }
+    }
+
+    final String icsContent = iCalendar.serialize();
+    final String fileName = 'cycle_calendar_${DateFormat('yyyyMMdd').format(DateTime.now())}.ics';
+
+    if (kIsWeb) {
+      // Web platform
+      final bytes = icsContent.codeUnits;
+      final blob = html.Blob([bytes], 'text/calendar');
+      final url = html.Url.createObjectUrlFromBlob(blob);
+      html.AnchorElement(href: url)
+        ..setAttribute('download', fileName)
+        ..click();
+      html.Url.revokeObjectUrl(url);
+    } else {
+      // Mobile platform
+      final directory = await getApplicationDocumentsDirectory();
+      final filePath = '${directory.path}/$fileName';
+      final file = File(filePath);
+      await file.writeAsString(icsContent);
+      await OpenFilex.open(filePath);
+    }
+  }
+}