using Data.SeaHavenIndustries.Enums;

namespace SeaHaven.Services.Helpers
{
    public static class WorkOrderBoardMutationRules
    {
        private static readonly HashSet<LifecycleStatus?> ReadOnlyStatuses =
            LifecycleStatusSets.Terminal.Cast<LifecycleStatus?>().ToHashSet();

        public static bool IsReadOnly(LifecycleStatus? status) => ReadOnlyStatuses.Contains(status);

        public static bool ShouldBlockStatusChangeWhenPastDue(string field, bool isPastDue)
            => field.Equals(WorkOrderBoardFieldNames.LifecycleStatus, StringComparison.OrdinalIgnoreCase) && isPastDue;

        /// <summary>
        /// SHOC rule: Incomplete + specific scheduled date + assignee → Scheduled.
        /// Week-only targets do not auto-schedule (same as <see cref="WorkOrderDerivedFields.ApplyAutoScheduleIfEligible"/>).
        /// </summary>
        public static bool ShouldAutoSchedule(
            LifecycleStatus? status,
            DateTime? scheduledDate,
            string? assignTo,
            bool? scheduleWeekOnly = null)
            => status == LifecycleStatus.Incomplete
               && scheduleWeekOnly != true
               && scheduledDate.HasValue
               && !string.IsNullOrWhiteSpace(assignTo);

        public static bool IsReschedule(DateTime? previousDate, DateTime? newDate)
            => previousDate.HasValue
               && newDate.HasValue
               && previousDate.Value.Date != newDate.Value.Date;

        public static DateOnly? ComputeOriginalWeek(DateTime? scheduledDate)
            => scheduledDate.HasValue
                ? DateOnly.FromDateTime(GetWeekStartMonday(scheduledDate.Value))
                : null;

        private static DateTime GetWeekStartMonday(DateTime date)
        {
            var diff = (7 + (date.DayOfWeek - DayOfWeek.Monday)) % 7;
            return date.Date.AddDays(-diff);
        }
    }
}