using Data.SeaHavenIndustries;
using Microsoft.EntityFrameworkCore;
using SeaHaven.DataServices.Interfaces;

namespace SeaHaven.DataServices.Implementation
{
    public sealed class WorkOrderWebhookDataService : IWorkOrderWebhookDataService
    {
        private readonly ApplicationDbContext _context;

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

        public async Task<WorkOrderWebhookPersistenceResult> ApplyAsync(
            WorkOrderWebhookMutation mutation,
            CancellationToken cancellationToken)
        {
            var prior = await _context.WorkOrderWebhookDeliveries
                .AsNoTracking()
                .SingleOrDefaultAsync(d => d.DeliveryId == mutation.DeliveryId, cancellationToken);

            if (prior != null)
                return ExistingDeliveryResult(prior, mutation.BodySha256);

            var workOrder = await _context.workOrders
                .SingleOrDefaultAsync(
                    w => w.ExternalWorkOrderId == mutation.ExternalWorkOrderId,
                    cancellationToken);

            if (workOrder == null)
            {
                var nextInternalNumber = Math.Max(
                        await _context.workOrders.MaxAsync(
                            w => (int?)w.Id,
                            cancellationToken) ?? 0,
                        0)
                    + 1;
                workOrder = new WorkOrder
                {
                    ExternalWorkOrderId = mutation.ExternalWorkOrderId,
                    WorkerOrderNumber = mutation.WorkerOrderNumber,
                    InternalWONumber = nextInternalNumber.ToString("D11"),
                    WorkerOrderTitle = mutation.Title ?? mutation.Description
                        ?? $"Imported work order {mutation.ExternalWorkOrderId}",
                    Description = mutation.Description,
                    Source = mutation.Source,
                    istemplate = false,
                    CreatedDate = mutation.CreatedAt ?? mutation.ProcessedAt.UtcDateTime
                };
                _context.workOrders.Add(workOrder);
            }

            var staleState = mutation.IsStateEvent
                && workOrder.ExternalLastOccurredAt.HasValue
                && mutation.OccurredAt < workOrder.ExternalLastOccurredAt.Value;

            if (mutation.IsStateEvent && !staleState)
            {
                var locationKey = mutation.SiteCode ?? mutation.Building;
                if (!string.IsNullOrWhiteSpace(locationKey))
                {
                    var location = await _context.Locations
                        .FirstOrDefaultAsync(
                            l => l.Name == locationKey || l.Title == locationKey,
                            cancellationToken);
                    if (location == null)
                    {
                        location = new Locations
                        {
                            Name = locationKey,
                            Title = mutation.Building,
                            Address1 = mutation.Address,
                            Status = "Active"
                        };
                        _context.Locations.Add(location);
                    }

                    workOrder.Locations = location;
                }

                workOrder.WorkerOrderNumber = mutation.WorkerOrderNumber;
                workOrder.WorkerOrderTitle = mutation.Title ?? mutation.Description;
                workOrder.Description = mutation.Description;
                workOrder.Status = mutation.IsCancelled ? "Cancelled" : mutation.Status;
                workOrder.Severity = mutation.Severity;
                workOrder.Priority = mutation.Priority;
                workOrder.Customer = mutation.Customer;
                workOrder.SiteCode = mutation.SiteCode;
                workOrder.Building = mutation.Building;
                workOrder.DueDate = mutation.DueDate;
                workOrder.DateReported = mutation.DateReported;
                workOrder.ScheduledStart = mutation.ScheduledStart;
                workOrder.Source = mutation.Source;
                workOrder.istemplate = false;
                workOrder.ExternalLastOccurredAt = mutation.OccurredAt;
            }

            if (mutation.CommentId != null)
            {
                var commentExists = await _context.Comments
                    .AnyAsync(c => c.ExternalCommentId == mutation.CommentId, cancellationToken);

                if (!commentExists)
                {
                    _context.Comments.Add(new Comments
                    {
                        ExternalCommentId = mutation.CommentId,
                        Commenttext = mutation.CommentText,
                        Commenter = mutation.Commenter,
                        CommentType = mutation.CommentType,
                        RecordType = "WorkOrder",
                        WorkOrder = workOrder,
                        CreatedDate = mutation.OccurredAt.UtcDateTime
                    });
                }
            }

            _context.WorkOrderWebhookDeliveries.Add(new WorkOrderWebhookDelivery
            {
                DeliveryId = mutation.DeliveryId,
                EventType = mutation.EventType,
                OccurredAt = mutation.OccurredAt,
                ProcessedAt = mutation.ProcessedAt,
                BodySha256 = mutation.BodySha256
            });

            try
            {
                await _context.SaveChangesAsync(cancellationToken);
                return new WorkOrderWebhookPersistenceResult(
                    WorkOrderWebhookPersistenceStatus.Applied,
                    staleState);
            }
            catch (DbUpdateException)
            {
                _context.ChangeTracker.Clear();
                var concurrent = await _context.WorkOrderWebhookDeliveries
                    .AsNoTracking()
                    .SingleOrDefaultAsync(d => d.DeliveryId == mutation.DeliveryId, cancellationToken);

                if (concurrent == null)
                    throw;

                return ExistingDeliveryResult(concurrent, mutation.BodySha256);
            }
        }

        private static WorkOrderWebhookPersistenceResult ExistingDeliveryResult(
            WorkOrderWebhookDelivery delivery,
            string bodySha256)
        {
            return new WorkOrderWebhookPersistenceResult(
                string.Equals(delivery.BodySha256, bodySha256, StringComparison.OrdinalIgnoreCase)
                    ? WorkOrderWebhookPersistenceStatus.Duplicate
                    : WorkOrderWebhookPersistenceStatus.HashConflict);
        }
    }
}