Share schedule-editing and starter-seed-state helpers across platforms

Shared/Model/ScheduleEditing.swift

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+//
+// ScheduleEditing.swift
+// Workouts
+//
+// Copyright 2026 Rouslan Zenetl. All Rights Reserved.
+//
+
+import Foundation
+import SwiftData
+
+/// Shared schedule-editing helpers used by both the iOS `ScheduleAddEditView` and the
+/// Mac `MacScheduleEditorSheet` / `MacSchedulesView` — weekday ordering, the
+/// minutes-from-midnight wire-format conversions, and the next-order helper for new
+/// schedules. Kept in `Shared/` (compiled into every target) so the two platforms never
+/// drift on these byte-identical semantics.
+enum ScheduleEditing {
+    /// Calendar weekday numbers in Monday-first display order (Mon…Sat = 2…7, Sun = 1).
+    static let weekdayOrder = [2, 3, 4, 5, 6, 7, 1]
+    /// Gregorian short names, 0-indexed from Sunday — weekday `n` is `symbols[n - 1]`.
+    static let weekdaySymbols = Calendar(identifier: .gregorian).shortWeekdaySymbols
+
+    /// A Date (today, local calendar) at the stored minutes-from-midnight, for the
+    /// hour-and-minute picker. Nil (no reminder yet) seeds a sensible 8:00 AM default.
+    static func time(fromMinutes minutes: Int?) -> Date {
+        let startOfDay = Calendar.current.startOfDay(for: Date())
+        return Calendar.current.date(byAdding: .minute, value: minutes ?? 8 * 60, to: startOfDay)
+            ?? startOfDay
+    }
+
+    /// The picked time back to minutes from midnight (local wall-clock).
+    static func minutesFromMidnight(of time: Date) -> Int {
+        let comps = Calendar.current.dateComponents([.hour, .minute], from: time)
+        return (comps.hour ?? 0) * 60 + (comps.minute ?? 0)
+    }
+
+    /// One past the highest existing schedule order — appends a new schedule to the end.
+    static func nextOrder(in modelContext: ModelContext) -> Int {
+        let existing = (try? modelContext.fetch(FetchDescriptor<Schedule>())) ?? []
+        return (existing.map(\.order).max() ?? -1) + 1
+    }
+}