//
// 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
    }
}
