namespace SeaHaven.Services.Helpers
{
    public enum WorkOrderAdvancedSearchDatePreset
    {
        ThisWeek,
        LastWeek,
        ThisMonth,
        Last3Months,
        NextWeek,
        NextMonth,
        Custom
    }

    public record WorkOrderSearchDateRange(DateOnly From, DateOnly To);

    public static class WorkOrderSearchDateRangeResolver
    {
        public static WorkOrderSearchDateRange Resolve(
            WorkOrderAdvancedSearchDatePreset? preset,
            DateOnly? dateFrom,
            DateOnly? dateTo,
            DateOnly? referenceDate = null)
        {
            var today = referenceDate ?? DateOnly.FromDateTime(DateTime.UtcNow);
            var resolvedPreset = preset ?? WorkOrderAdvancedSearchDatePreset.ThisWeek;

            if (resolvedPreset == WorkOrderAdvancedSearchDatePreset.Custom)
            {
                if (!dateFrom.HasValue || !dateTo.HasValue)
                    throw new ArgumentException("dateFrom and dateTo are required when datePreset is custom.");

                if (dateTo.Value < dateFrom.Value)
                    throw new ArgumentException("dateTo must be on or after dateFrom.");

                return new WorkOrderSearchDateRange(dateFrom.Value, dateTo.Value);
            }

            return resolvedPreset switch
            {
                WorkOrderAdvancedSearchDatePreset.ThisWeek => ThisIsoWeek(today),
                WorkOrderAdvancedSearchDatePreset.LastWeek => LastIsoWeek(today),
                WorkOrderAdvancedSearchDatePreset.ThisMonth => ThisMonth(today),
                WorkOrderAdvancedSearchDatePreset.Last3Months => Last3Months(today),
                WorkOrderAdvancedSearchDatePreset.NextWeek => NextIsoWeek(today),
                WorkOrderAdvancedSearchDatePreset.NextMonth => NextMonth(today),
                _ => ThisIsoWeek(today)
            };
        }

        public static DateOnly GetIsoWeekStart(DateOnly date)
        {
            var diff = (7 + (date.DayOfWeek - DayOfWeek.Monday)) % 7;
            return date.AddDays(-diff);
        }

        private static WorkOrderSearchDateRange ThisIsoWeek(DateOnly today)
        {
            var start = GetIsoWeekStart(today);
            return new WorkOrderSearchDateRange(start, start.AddDays(6));
        }

        private static WorkOrderSearchDateRange LastIsoWeek(DateOnly today)
        {
            var start = GetIsoWeekStart(today).AddDays(-7);
            return new WorkOrderSearchDateRange(start, start.AddDays(6));
        }

        private static WorkOrderSearchDateRange NextIsoWeek(DateOnly today)
        {
            var start = GetIsoWeekStart(today).AddDays(7);
            return new WorkOrderSearchDateRange(start, start.AddDays(6));
        }

        private static WorkOrderSearchDateRange ThisMonth(DateOnly today)
        {
            var start = new DateOnly(today.Year, today.Month, 1);
            var end = start.AddMonths(1).AddDays(-1);
            return new WorkOrderSearchDateRange(start, end);
        }

        private static WorkOrderSearchDateRange NextMonth(DateOnly today)
        {
            var start = new DateOnly(today.Year, today.Month, 1).AddMonths(1);
            var end = start.AddMonths(1).AddDays(-1);
            return new WorkOrderSearchDateRange(start, end);
        }

        private static WorkOrderSearchDateRange Last3Months(DateOnly today)
        {
            var end = today;
            var start = today.AddMonths(-3);
            return new WorkOrderSearchDateRange(start, end);
        }
    }
}