feat: event reminders + default reminder setting + local notifications (iOS)

Per-event reminders (multiple, local calendars only) in the editor, prefilled
from a new "default reminder" setting that applies to all events otherwise.
CalEvent gains `reminders`; AppSettings/SettingsSync sync default_reminder_minutes
(always group). New NotificationScheduler requests permission and schedules the
soonest ≤60 upcoming reminders via UNUserNotificationCenter, rescheduling on
load/sync/edit and when the default changes (skipped in group overlay).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Calendarr iOS/Models/AppSettings.swift

@@ -18,6 +18,7 @@ struct AppSettings: Codable {
     var lineColor: String = "#3A3A3C"
     var privateEventVisibility: String = "busy"   // 'hidden' | 'busy'
     var groupVisibleCalendarId: Int? = nil
+    var defaultReminderMinutes: Int? = nil         // minutes before start; nil = off
 
     enum CodingKeys: String, CodingKey {
         case defaultView = "default_view"
@@ -37,6 +38,7 @@ struct AppSettings: Codable {
         case lineColor = "line_color"
         case privateEventVisibility = "private_event_visibility"
         case groupVisibleCalendarId = "group_visible_calendar_id"
+        case defaultReminderMinutes = "default_reminder_minutes"
     }
 
     init() {}
@@ -66,6 +68,7 @@ struct AppSettings: Codable {
         lineColor         = try c.decodeIfPresent(String.self, forKey: .lineColor)         ?? d.lineColor
         privateEventVisibility = try c.decodeIfPresent(String.self, forKey: .privateEventVisibility) ?? d.privateEventVisibility
         groupVisibleCalendarId = try c.decodeIfPresent(Int.self, forKey: .groupVisibleCalendarId)
+        defaultReminderMinutes = try c.decodeIfPresent(Int.self, forKey: .defaultReminderMinutes)
     }
 }
 

Calendarr iOS/Models/CalEvent.swift

@@ -41,6 +41,8 @@ struct CalEvent: Identifiable, Hashable {
     // Server-decorated title for the group combined view (group icon / owner
     // prefix); rendered in group mode while `title` stays raw for editing.
     var displayTitle: String? = nil
+    // Reminder offsets in minutes-before-start (0 = at start). Local events only.
+    var reminders: [Int] = []
 
     // Group view supplies a server-resolved colour; otherwise per-event then calendar colour.
     var effectiveColor: String { displayColor ?? color ?? calendarColor }
@@ -82,7 +84,8 @@ struct CalEvent: Identifiable, Hashable {
             owner: EventPerson.from(json["owner"]),
             isGroupEvent: json["is_group_event"] as? Bool ?? false,
             displayColor: (json["display_color"] as? String).flatMap { $0.isEmpty ? nil : $0 },
-            displayTitle: (json["display_title"] as? String).flatMap { $0.isEmpty ? nil : $0 }
+            displayTitle: (json["display_title"] as? String).flatMap { $0.isEmpty ? nil : $0 },
+            reminders: (json["reminders"] as? [Int]) ?? (json["reminders"] as? [Any])?.compactMap { ($0 as? Int) ?? Int("\($0)") } ?? []
         )
     }
 }

Calendarr iOS/Models/CalendarStore.swift

@@ -264,6 +264,15 @@ class CalendarStore {
             return !hiddenCalendarKeys.contains(key)
                 && !banishedCalendarKeys.contains(key)
         }
+        // Personal events drive local reminder notifications.
+        NotificationScheduler.reschedule(events: allCachedEvents)
+    }
+
+    /// Recompute scheduled reminder notifications from the personal cache
+    /// (skipped while a group overlay is active).
+    func rescheduleNotifications() {
+        guard activeGroup == nil else { return }
+        NotificationScheduler.reschedule(events: allCachedEvents)
     }
 
     /// Optimistically drop a just-deleted event from the cache so it disappears

Calendarr iOS/Models/ReminderOptions.swift

@@ -0,0 +1,37 @@
+import Foundation
+
+/// Reminder offset options (minutes before an event's start; 0 = at start) and
+/// their localized labels. Shared by the event editor, the settings default
+/// picker, and the notification scheduler so the choices stay consistent.
+enum ReminderOptions {
+    /// Selectable offsets in minutes-before-start.
+    static let all: [Int] = [0, 5, 10, 15, 30, 60, 120, 1440, 2880]
+
+    private static func isEnglish(_ appLang: String) -> Bool {
+        if appLang == "en" { return true }
+        if appLang == "de" { return false }
+        return (Locale.current.language.languageCode?.identifier ?? "de").hasPrefix("en")
+    }
+
+    static func label(_ minutes: Int, _ appLang: String) -> String {
+        let en = isEnglish(appLang)
+        if minutes <= 0 { return en ? "At start time" : "Zur Startzeit" }
+        if minutes < 60 { return en ? "\(minutes) min before" : "\(minutes) Min. vorher" }
+        if minutes < 1440 {
+            let h = minutes / 60
+            return en ? "\(h) h before" : "\(h) Std. vorher"
+        }
+        let d = minutes / 1440
+        return en ? "\(d) day\(d == 1 ? "" : "s") before" : "\(d) Tag\(d == 1 ? "" : "e") vorher"
+    }
+
+    static func sectionTitle(_ l: String) -> String { isEnglish(l) ? "Reminders" : "Benachrichtigungen" }
+    static func addLabel(_ l: String) -> String { isEnglish(l) ? "Add reminder" : "Benachrichtigung hinzufügen" }
+    static func off(_ l: String) -> String { isEnglish(l) ? "Off" : "Aus" }
+    static func defaultTitle(_ l: String) -> String { isEnglish(l) ? "Default reminder" : "Standardbenachrichtigung" }
+    static func defaultFooter(_ l: String) -> String {
+        isEnglish(l)
+            ? "Applies to all events unless an event has its own reminders."
+            : "Gilt für alle Termine, sofern ein Termin keine eigenen Benachrichtigungen hat."
+    }
+}

Calendarr iOS/Services/CalendarrAPI.swift

@@ -229,7 +229,7 @@ class CalendarrAPI {
 
     func createLocalEvent(calendarId: Int, title: String, start: Date, end: Date,
                           isAllDay: Bool, location: String, description: String, color: String?,
-                          isPrivate: Bool = false) async throws -> CalEvent {
+                          isPrivate: Bool = false, reminders: [Int]? = nil) async throws -> CalEvent {
         var body: [String: Any] = [
             "calendar_id": calendarId,
             "title": title,
@@ -241,6 +241,7 @@ class CalendarrAPI {
             "private": isPrivate
         ]
         if let c = color, !c.isEmpty { body["color"] = c }
+        if let reminders { body["reminders"] = reminders }
         let data = try await request("/api/local/events", method: "POST", body: body)
         guard let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
               let ev = CalEvent.from(json: json) else { throw APIError.decodingError }
@@ -249,7 +250,7 @@ class CalendarrAPI {
 
     func updateLocalEvent(uid: String, title: String, start: Date, end: Date,
                           isAllDay: Bool, location: String, description: String, color: String?,
-                          isPrivate: Bool = false) async throws {
+                          isPrivate: Bool = false, reminders: [Int]? = nil) async throws {
         var body: [String: Any] = [
             "title": title,
             "start": formatISO(start, allDay: isAllDay),
@@ -260,6 +261,7 @@ class CalendarrAPI {
             "private": isPrivate
         ]
         if let c = color { body["color"] = c }
+        if let reminders { body["reminders"] = reminders }
         _ = try await request("/api/local/events/\(uid)", method: "PUT", body: body)
     }
 

Calendarr iOS/Services/NotificationScheduler.swift

@@ -0,0 +1,65 @@
+import Foundation
+import UserNotifications
+
+extension Notification.Name {
+    /// Posted when the default-reminder setting changes, so the calendar host
+    /// can recompute the scheduled local notifications from its cached events.
+    static let rescheduleReminders = Notification.Name("rescheduleReminders")
+}
+
+/// Schedules local OS notifications for upcoming events. Per-event reminders
+/// (local events) take precedence; otherwise the user's default reminder applies
+/// to every event (incl. external). Re-run whenever events or the default change.
+enum NotificationScheduler {
+
+    static func requestAuthorizationIfNeeded() {
+        UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) { _, _ in }
+    }
+
+    /// Recompute and (re)schedule notifications from the given events. The iOS
+    /// pending-notification cap is 64, so only the soonest are scheduled.
+    static func reschedule(events: [CalEvent]) {
+        let center = UNUserNotificationCenter.current()
+        center.getNotificationSettings { settings in
+            guard settings.authorizationStatus == .authorized
+                    || settings.authorizationStatus == .provisional else { return }
+
+            let defaultMin = (UserDefaults.standard.object(forKey: "defaultReminderMinutes") as? Int) ?? -1
+            let now = Date()
+            var pending: [(fire: Date, event: CalEvent)] = []
+            for ev in events {
+                let offsets = ev.reminders.isEmpty
+                    ? (defaultMin >= 0 ? [defaultMin] : [])
+                    : ev.reminders
+                for m in offsets {
+                    let fire = ev.startDate.addingTimeInterval(-Double(m) * 60)
+                    if fire > now { pending.append((fire, ev)) }
+                }
+            }
+            pending.sort { $0.fire < $1.fire }
+            let limited = pending.prefix(60)  // stay safely under the 64 system cap
+
+            center.removeAllPendingNotificationRequests()
+            for item in limited {
+                let content = UNMutableNotificationContent()
+                content.title = item.event.title
+                content.body = bodyText(item.event)
+                content.sound = .default
+                let comps = Calendar.current.dateComponents(
+                    [.year, .month, .day, .hour, .minute, .second], from: item.fire)
+                let trigger = UNCalendarNotificationTrigger(dateMatching: comps, repeats: false)
+                center.add(UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger))
+            }
+        }
+    }
+
+    private static func bodyText(_ ev: CalEvent) -> String {
+        var parts: [String] = []
+        if !ev.isAllDay {
+            let f = DateFormatter(); f.timeStyle = .short; f.dateStyle = .none
+            parts.append(f.string(from: ev.startDate))
+        }
+        if !ev.location.isEmpty { parts.append(ev.location) }
+        return parts.joined(separator: " · ")
+    }
+}

Calendarr iOS/Services/SettingsSync.swift

@@ -37,6 +37,7 @@ enum SettingsSync {
         static let defaultView       = "defaultView"
         static let weekStartDay      = "weekStartDay"
         static let dimPastEvents     = "dimPastEvents"
+        static let defaultReminder   = "defaultReminderMinutes"  // Int, -1 = off
         // master switch
         static let enabled           = "settingsSync"
     }
@@ -71,6 +72,8 @@ enum SettingsSync {
         s.defaultView       = str(Key.defaultView,  "month")
         s.weekStartDay      = str(Key.weekStartDay, "monday")
         s.dimPastEvents     = UserDefaults.standard.bool(forKey: Key.dimPastEvents)
+        let rem = int(Key.defaultReminder, -1)
+        s.defaultReminderMinutes = rem < 0 ? nil : rem
         return s
     }
 
@@ -84,6 +87,7 @@ enum SettingsSync {
         d.set(s.defaultView,   forKey: Key.defaultView)
         d.set(s.weekStartDay,  forKey: Key.weekStartDay)
         d.set(s.dimPastEvents, forKey: Key.dimPastEvents)
+        d.set(s.defaultReminderMinutes ?? -1, forKey: Key.defaultReminder)
         guard includeOptional else { return }
         // NOTE: textColor / backgroundColor / lineColor are intentionally NOT
         // synced – the server has no columns for them (iOS-only). Writing the
@@ -134,6 +138,7 @@ enum SettingsSync {
         merged.defaultView   = local.defaultView
         merged.weekStartDay  = local.weekStartDay
         merged.dimPastEvents = local.dimPastEvents
+        merged.defaultReminderMinutes = local.defaultReminderMinutes
         if isEnabled {
             merged.primaryColor      = local.primaryColor
             merged.accentColor       = local.accentColor

Calendarr iOS/Views/Calendar/CalendarHostView.swift

@@ -95,6 +95,9 @@ struct CalendarHostView: View {
         .onReceive(NotificationCenter.default.publisher(for: .manualSyncRequested)) { _ in
             Task { await forceReload() }
         }
+        .onReceive(NotificationCenter.default.publisher(for: .rescheduleReminders)) { _ in
+            store.rescheduleNotifications()
+        }
     }
 
     // MARK: – Liquid Glass variant
@@ -162,6 +165,9 @@ struct CalendarHostView: View {
         .onReceive(NotificationCenter.default.publisher(for: .manualSyncRequested)) { _ in
             Task { await forceReload() }
         }
+        .onReceive(NotificationCenter.default.publisher(for: .rescheduleReminders)) { _ in
+            store.rescheduleNotifications()
+        }
     }
 
     // MARK: – Top bar (flat mode)
@@ -407,6 +413,8 @@ struct CalendarHostView: View {
     // MARK: – Loading logic
 
     private func startup() async {
+        // Ask for notification permission early so reminders can be scheduled.
+        NotificationScheduler.requestAuthorizationIfNeeded()
         // 0. Pull settings first so week-start / default-view are correct
         //    before we compute the initial range and load events.
         await SettingsSync.pull(api: api)

Calendarr iOS/Views/Calendar/EventEditorSheet.swift

@@ -10,6 +10,7 @@ struct EventEditorSheet: View {
 
     @Environment(\.dismiss) var dismiss
     @AppStorage("appLanguage") private var appLang = "system"
+    @AppStorage("defaultReminderMinutes") private var defaultReminderMinutes = -1
     @State private var title = ""
     @State private var isAllDay = false
     @State private var startDate = Date()
@@ -19,6 +20,7 @@ struct EventEditorSheet: View {
     @State private var selectedCalendarId: String = ""
     @State private var color = ""
     @State private var isPrivate = false
+    @State private var reminders: [Int] = []
     @State private var isSaving = false
     @State private var error = ""
 
@@ -81,6 +83,27 @@ struct EventEditorSheet: View {
                         Toggle(L10n.t("event.private", appLang), isOn: $isPrivate)
                             .tint(Color.accentColor)
                     }
+
+                    Section(ReminderOptions.sectionTitle(appLang)) {
+                        ForEach(Array(reminders.enumerated()), id: \.offset) { idx, _ in
+                            Picker(ReminderOptions.sectionTitle(appLang), selection: Binding(
+                                get: { reminders.indices.contains(idx) ? reminders[idx] : 0 },
+                                set: { if reminders.indices.contains(idx) { reminders[idx] = $0 } }
+                            )) {
+                                ForEach(ReminderOptions.all, id: \.self) { opt in
+                                    Text(ReminderOptions.label(opt, appLang)).tag(opt)
+                                }
+                            }
+                            .labelsHidden()
+                        }
+                        .onDelete { reminders.remove(atOffsets: $0) }
+                        Button {
+                            let next = ReminderOptions.all.first { !reminders.contains($0) } ?? 15
+                            reminders.append(next)
+                        } label: {
+                            Label(ReminderOptions.addLabel(appLang), systemImage: "bell.badge.plus")
+                        }
+                    }
                 }
 
                 Section(L10n.t("event.color_section", appLang)) {
@@ -149,6 +172,7 @@ struct EventEditorSheet: View {
             notes = ev.notes
             color = ev.color ?? ""
             isPrivate = ev.isPrivate
+            reminders = ev.reminders
             // HA events use "homeassistant-42" in CalEvent but "ha-42" in WritableCalendar
             if ev.source == "homeassistant" {
                 let num = ev.calendarId.replacingOccurrences(of: "homeassistant-", with: "")
@@ -167,6 +191,7 @@ struct EventEditorSheet: View {
             notes = ev.notes
             color = ev.color ?? ""
             isPrivate = ev.isPrivate
+            reminders = ev.reminders
             selectedCalendarId = store.writableCalendars.first?.id ?? ""
         } else {
             let cal = Calendar.current
@@ -174,6 +199,8 @@ struct EventEditorSheet: View {
                                  minute: 0, second: 0, of: initialDate) ?? initialDate
             endDate = startDate.addingTimeInterval(3600)
             selectedCalendarId = store.writableCalendars.first?.id ?? ""
+            // New events inherit the user's default reminder (editable).
+            if defaultReminderMinutes >= 0 { reminders = [defaultReminderMinutes] }
         }
     }
 
@@ -193,7 +220,7 @@ struct EventEditorSheet: View {
                 case "local":
                     try await api.updateLocalEvent(uid: ev.id, title: title, start: start, end: end,
                                                    isAllDay: isAllDay, location: location, description: notes, color: colorVal,
-                                                   isPrivate: isPrivate)
+                                                   isPrivate: isPrivate, reminders: reminders)
                 case "homeassistant":
                     // No update API exists – delete the old event and recreate with new data.
                     let rawId = ev.calendarId.replacingOccurrences(of: "homeassistant-", with: "")
@@ -214,7 +241,7 @@ struct EventEditorSheet: View {
                     _ = try await api.createLocalEvent(calendarId: cal.numericId, title: title,
                                                        start: start, end: end, isAllDay: isAllDay,
                                                        location: location, description: notes, color: colorVal,
-                                                       isPrivate: isPrivate)
+                                                       isPrivate: isPrivate, reminders: reminders)
                 case "google":
                     try await api.createGoogleEvent(calendarDbId: cal.numericId, title: title,
                                                     start: start, end: end, isAllDay: isAllDay,

Calendarr iOS/Views/SettingsView.swift

@@ -22,6 +22,7 @@ struct SettingsView: View {
     @AppStorage("defaultView")       private var defaultView = "month"
     @AppStorage("weekStartDay")      private var weekStartDay = "monday"
     @AppStorage("dimPastEvents")     private var dimPastEvents = false
+    @AppStorage("defaultReminderMinutes") private var defaultReminderMinutes = -1
 
     // Profile chapter (server-backed; loaded on appear).
     @State private var displayName = ""
@@ -37,6 +38,7 @@ struct SettingsView: View {
             Form {
                 profilSection
                 privatsphaereSection
+                benachrichtigungenSection
                 geteilterKalenderSection
                 liquidGlassSection
                 cacheSection
@@ -105,6 +107,27 @@ struct SettingsView: View {
         }
     }
 
+    // MARK: – Benachrichtigungen
+
+    var benachrichtigungenSection: some View {
+        Section {
+            Picker(ReminderOptions.defaultTitle(appLang), selection: $defaultReminderMinutes) {
+                Text(ReminderOptions.off(appLang)).tag(-1)
+                ForEach(ReminderOptions.all, id: \.self) { m in
+                    Text(ReminderOptions.label(m, appLang)).tag(m)
+                }
+            }
+            .onChange(of: defaultReminderMinutes) { _, _ in
+                SettingsSync.push(api: api)
+                NotificationCenter.default.post(name: .rescheduleReminders, object: nil)
+            }
+        } header: {
+            Text(ReminderOptions.sectionTitle(appLang))
+        } footer: {
+            Text(ReminderOptions.defaultFooter(appLang)).font(.caption)
+        }
+    }
+
     // MARK: – Privatsphäre
 
     var privatsphaereSection: some View {