using Data.SeaHavenIndustries;
using Data.SeaHavenIndustries.Enums;
using SeaHaven.Services.Exceptions;

namespace SeaHaven.Services.Helpers
{
    public static class WorkOrderBoardFieldMutations
    {
        public static List<BoardFieldChange> ApplyAssignTo(WorkOrder workOrder, string? value, string auditField = "AssignTo")
        {
            var normalized = string.IsNullOrWhiteSpace(value) ? null : value.Trim();
            var old = workOrder.AssignTo;
            var changes = new List<BoardFieldChange>();

            if (old != normalized)
            {
                workOrder.AssignTo = normalized;
                changes.Add(BoardFieldChange.AssignmentChanged(auditField, old, normalized));
            }

            changes.AddRange(ApplyAutoScheduleSideEffects(workOrder));
            return changes;
        }

        public static List<BoardFieldChange> ApplyScheduledDate(
            WorkOrder workOrder,
            DateTime? parsed,
            string auditField = "ScheduledDate",
            bool incrementRescheduleOnChange = true)
        {
            var previousDate = workOrder.ScheduledDate;
            var changes = new List<BoardFieldChange>();
            var oldFormatted = FormatDate(previousDate);
            var newFormatted = FormatDate(parsed);

            if (oldFormatted == newFormatted)
                return changes;

            workOrder.ScheduledDate = parsed;
            changes.Add(BoardFieldChange.Changed(auditField, oldFormatted, newFormatted));

            if (!workOrder.OriginalDate.HasValue && parsed.HasValue)
            {
                workOrder.OriginalDate = DateOnly.FromDateTime(parsed.Value);
                var originalWeek = WorkOrderBoardMutationRules.ComputeOriginalWeek(parsed);
                if (originalWeek.HasValue)
                    workOrder.OriginalWeek = originalWeek;
            }

            if (incrementRescheduleOnChange && WorkOrderBoardMutationRules.IsReschedule(previousDate, parsed))
            {
                var oldCount = workOrder.RescheduleCount.ToString();
                workOrder.RescheduleCount++;
                changes.Add(BoardFieldChange.Changed(
                    WorkOrderBoardFieldNames.RescheduleCount,
                    oldCount,
                    workOrder.RescheduleCount.ToString()));
            }

            changes.AddRange(ApplyAutoScheduleSideEffects(workOrder));
            return changes;
        }

        public static List<BoardFieldChange> ApplyAutoScheduleSideEffects(WorkOrder workOrder)
        {
            var changes = new List<BoardFieldChange>();
            if (!WorkOrderBoardMutationRules.ShouldAutoSchedule(
                    workOrder.LifecycleStatus,
                    workOrder.ScheduledDate,
                    workOrder.AssignTo,
                    workOrder.ScheduleWeekOnly))
                return changes;

            var old = workOrder.LifecycleStatus?.ToString();
            workOrder.LifecycleStatus = LifecycleStatus.Scheduled;
            workOrder.Status = WorkOrderDerivedFields.GetLifecycleStatusLabel(LifecycleStatus.Scheduled);
            changes.Add(BoardFieldChange.StatusChanged("LifecycleStatus", old, LifecycleStatus.Scheduled.ToString()));
            return changes;
        }

        public static BoardFieldChange ApplyApptTime(WorkOrder workOrder, Dispatch dispatch, string? value)
        {
            if (!WorkOrderBoardApptTimeParser.TryParse(value, out var start, out var end, out var error))
                throw new WorkOrderBoardValidationException("InvalidValue", error ?? "Invalid apptTime.");

            var apptDate = dispatch.ScheduledDate ?? workOrder.ScheduledDate;
            var oldStart = FormatDateTime(workOrder.ScheduledStart);
            var oldEnd = FormatDateTime(workOrder.ScheduledEnd);

            workOrder.ScheduledStart = WorkOrderBoardApptTimeParser.ToScheduledInstant(apptDate, start);
            workOrder.ScheduledEnd = WorkOrderBoardApptTimeParser.ToScheduledInstant(apptDate, end);

            var newStart = FormatDateTime(workOrder.ScheduledStart);
            var newEnd = FormatDateTime(workOrder.ScheduledEnd);
            var oldCombined = FormatApptRange(oldStart, oldEnd);
            var newCombined = FormatApptRange(newStart, newEnd);

            if (oldCombined == newCombined)
                return BoardFieldChange.Unchanged("ApptTime", dispatch.Id);

            return BoardFieldChange.Changed("ApptTime", oldCombined, newCombined, dispatch.Id);
        }

        public static void SetInitialLifecycleStatus(WorkOrder workOrder)
        {
            workOrder.LifecycleStatus = LifecycleStatus.Incomplete;
            workOrder.Status = WorkOrderDerivedFields.GetLifecycleStatusLabel(LifecycleStatus.Incomplete);
        }

        private static string? FormatDate(DateTime? value) => value?.ToString("yyyy-MM-dd");
        private static string? FormatDateTime(DateTime? value) => value?.ToString("O");
        private static string? FormatApptRange(string? start, string? end)
            => start == null && end == null ? null : $"{start}|{end}";

        public sealed record BoardFieldChange(
            string FieldName,
            string? OldValue,
            string? NewValue,
            AuditActionType Action,
            int? DispatchId,
            bool HasChanged)
        {
            public static BoardFieldChange Unchanged(string fieldName, int? dispatchId = null)
                => new(fieldName, null, null, AuditActionType.FieldChanged, dispatchId, false);

            public static BoardFieldChange Changed(string fieldName, string? oldValue, string? newValue, int? dispatchId = null)
                => new(fieldName, oldValue, newValue, AuditActionType.FieldChanged, dispatchId, true);

            public static BoardFieldChange StatusChanged(string fieldName, string? oldValue, string? newValue)
                => new(fieldName, oldValue, newValue, AuditActionType.StatusChanged, null, true);

            public static BoardFieldChange AssignmentChanged(string fieldName, string? oldValue, string? newValue)
                => new(fieldName, oldValue, newValue, AuditActionType.AssignmentChanged, null, true);
        }
    }
}