using Data.SeaHavenIndustries;
using Data.SeaHavenIndustries.Enums;
using Microsoft.EntityFrameworkCore;
using SeaHaven.DataServices.Helpers;
using SeaHaven.DataServices.Interfaces;
using SeaHaven.DataServices.Models;

namespace SeaHaven.DataServices.Implementation
{
    public class NotificationFeedDataService : INotificationFeedDataService
    {
        private static readonly string[] TerminalDispatchStatuses = { "Completed", "Verified", "Cancelled", "Canceled" };

        private readonly ApplicationDbContext _context;

        public NotificationFeedDataService(ApplicationDbContext context)
        {
            _context = context;
        }

        public async Task<UnassignedWorkOrdersSummary> GetUnassignedSummaryAsync(
            int? accountId, CancellationToken cancellationToken)
        {
            var summary = await OpenWorkOrders(new NotificationFeedScope(accountId, null))
                .Where(w => w.AssignTo == null || w.AssignTo == "")
                .GroupBy(_ => 1)
                .Select(group => new UnassignedWorkOrdersSummary
                {
                    Count = group.Count(),
                    LatestCreatedAt = group.Max(w => w.CreatedDate)
                })
                .FirstOrDefaultAsync(cancellationToken);

            return summary ?? new UnassignedWorkOrdersSummary();
        }

        public Task<NotificationCandidatePage> GetAvetaMissingAsync(
            NotificationFeedScope scope, DateOnly today, int limit, CancellationToken cancellationToken)
        {
            // Same rule as the dashboard's Aveta Pending tile so the two counts agree.
            var windowStart = today.ToDateTime(TimeOnly.MinValue);
            var windowEnd = today.AddDays(2).ToDateTime(TimeOnly.MinValue);
            var candidates = OpenWorkOrders(scope)
                .Where(w => w.AvetaRequired
                    && w.ScheduledDate >= windowStart
                    && w.ScheduledDate < windowEnd
                    && !w.workOrderAttachments!.Any(attachment =>
                        (attachment.IsDeleted == null || attachment.IsDeleted == false)
                        && attachment.Category == WorkOrderMediaCategory.Aveta));

            return PageAsync(candidates, limit, cancellationToken);
        }

        public Task<NotificationCandidatePage> GetNoVendorAsync(
            NotificationFeedScope scope, DateTime cutoff, int limit, CancellationToken cancellationToken)
        {
            // "Has a vendor" matches the vendor reminders: any live non-terminal dispatch that
            // points at the work order directly or links it through DispatchWorkOrders. Soft-deleted
            // dispatches are ignored so a removed dispatch does not keep the row out of No Vendor.
            var candidates = OpenWorkOrders(scope)
                .Where(w => w.ScheduledDate.HasValue
                    && w.ScheduledDate.Value <= cutoff
                    && !_context.Dispatches.Any(d => d.WorkOrderId == w.Id
                        && (d.IsDeleted == null || d.IsDeleted == false)
                        && !TerminalDispatchStatuses.Contains(d.Status ?? ""))
                    && !_context.DispatchWorkOrders.Any(link => link.WorkOrderId == w.Id
                        && link.Dispatch != null
                        && (link.Dispatch.IsDeleted == null || link.Dispatch.IsDeleted == false)
                        && !TerminalDispatchStatuses.Contains(link.Dispatch.Status ?? "")));

            return PageAsync(candidates, limit, cancellationToken);
        }

        private IQueryable<WorkOrder> OpenWorkOrders(NotificationFeedScope scope)
        {
            var workOrders = WorkOrderBoardQueryFilters.ApplyBaseScope(_context.workOrders.AsNoTracking());
            if (scope.AccountId is int accountId)
                workOrders = WorkOrderBoardQueryFilters.ApplyAccountScope(workOrders, accountId);
            if (scope.DispatcherId != null)
                workOrders = workOrders.Where(w => w.AssignTo == scope.DispatcherId);

            return workOrders.Where(w => w.LifecycleStatus != LifecycleStatus.Completed
                && w.LifecycleStatus != LifecycleStatus.Canceled
                && (w.LifecycleStatus != null
                    || ((w.LegacyStatus ?? w.Status) != "Done"
                        && (w.LegacyStatus ?? w.Status) != "Completed"
                        && (w.LegacyStatus ?? w.Status) != "Complete"
                        && (w.LegacyStatus ?? w.Status) != "Closed"
                        && (w.LegacyStatus ?? w.Status) != "Canceled"
                        && (w.LegacyStatus ?? w.Status) != "Cancelled")));
        }

        private static async Task<NotificationCandidatePage> PageAsync(
            IQueryable<WorkOrder> candidates, int limit, CancellationToken cancellationToken)
        {
            var total = await candidates.CountAsync(cancellationToken);
            if (total == 0)
                return new NotificationCandidatePage();

            var items = await candidates
                .OrderByDescending(w => w.ScheduledDate)
                .ThenByDescending(w => w.Id)
                .Take(limit)
                .Select(w => new NotificationWorkOrderCandidate
                {
                    Id = w.Id,
                    Number = w.InternalWONumber ?? w.WorkerOrderNumber,
                    ScheduledDate = w.ScheduledDate!.Value
                })
                .ToListAsync(cancellationToken);

            return new NotificationCandidatePage { Total = total, Items = items };
        }
    }
}