using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using Comal.Classes;
using H.Pipes.Extensions;
using InABox.Core;
using PRSClasses;
using Syncfusion.Windows.Tools.Controls;

namespace Comal.Stores
{
    internal class RequisitionStore : BaseStore<Requisition>
    {
        private readonly bool _debug = true;

        private void Log(string format, params object[] values)
        {
            if (_debug)
                Logger.Send(LogType.Information, UserID, string.Format("- RequisitionStore:" + format, values));
        }

        private bool NeedsUpdating<T>(Requisition entity, Expression<Func<Requisition, T>> property)
        {
            // If this is a new Requisition, we don't need to do anything
            if (entity.HasOriginalValue(x => x.ID))
            {
                var originalid = entity.GetOriginalValue(x => x.ID);
                if (originalid == Guid.Empty)
                {
                    Log("NeedsUpdating() return false - original id is empty");
                    return false;
                }
            }

            // if the Property has not changed, we don't need to do anything
            if (!entity.HasOriginalValue(property))
            {
                Log("NeedsUpdating() return false - {0} has not changed", property.ToString());
                return false;
            }

            return true;
        }

        private bool LoadRequisitionItems(Requisition entity, ref IEnumerable<RequisitionItem> requisitionitems)
        {
            if (requisitionitems == null)
                requisitionitems = Provider.Query(
                    new Filter<RequisitionItem>(x => x.RequisitionLink.ID).IsEqualTo(entity.ID)
                ).Rows.Select(x => x.ToObject<RequisitionItem>());
            return requisitionitems.Any();
        }

        private bool LoadDeliveryItems(Requisition entity, ref IEnumerable<DeliveryItem> deliveryitems)
        {
            if (deliveryitems == null)
                deliveryitems = Provider.Query(
                    new Filter<DeliveryItem>(x => x.RequisitionLink.ID).IsEqualTo(entity.ID),
                    new Columns<DeliveryItem>(x => x.ID, x => x.DeliveredDate)
                ).Rows.Select(x => x.ToObject<DeliveryItem>());
            return deliveryitems.Any();
        }

        #region TakenBy

        private void UpdateTakenBy(Requisition entity, ref IEnumerable<RequisitionItem> items, ref IEnumerable<DeliveryItem> deliveryitems)
        {
            Log("UpdateTakenBy() - starting");

            if (!NeedsUpdating(entity, x => x.TakenBy))
                return;

            if (!LoadDeliveryItems(entity, ref deliveryitems))
            {
                Log("UpdateTakenBy() - no delivery items to update");
                return;
            }

            foreach (var deliveryitem in deliveryitems)
                if (entity.TakenBy.IsValid() && deliveryitem.DeliveredDate.IsEmpty())
                {
                    Log("UpdateTakenBy() - Setting DeliveryDate");
                    deliveryitem.DeliveredDate = DateTime.Now;
                }
                else if (!entity.TakenBy.IsValid() && !deliveryitem.DeliveredDate.IsEmpty())
                {
                    Log("UpdateTakenBy() - Clearing DeliveryDate");
                    deliveryitem.DeliveredDate = DateTime.MinValue;
                }

            var updates = deliveryitems.Where(x => x.IsChanged());
            if (updates.Any())
                FindSubStore<DeliveryItem>().Save(updates,
                    entity.TakenBy.IsValid() ? "Requisition taken by " + entity.TakenBy.Code : "Requisition [TakenBy] has been cleared");

            Log("UpdateTakenBy() - done");
        }

        #endregion

        protected override void BeforeSave(Requisition entity)
        {
            base.BeforeSave(entity);

            if (entity.TakenBy.IsValid() || entity.Delivery.Completed != DateTime.MinValue || entity.Delivery.Delivered != DateTime.MinValue)
            {
                if (entity.Archived.IsEmpty())
                    entity.Archived = DateTime.Now;
            }
            else
            {
                if (!entity.Archived.IsEmpty())
                    entity.Archived = DateTime.MinValue;
            }
        }

        protected override void AfterSave(Requisition entity)
        {
            base.AfterSave(entity);

            IEnumerable<RequisitionItem> requisitionitems = null;
            IEnumerable<DeliveryItem> deliveryitems = null;
            
            UpdateDeliveryItems(entity, ref requisitionitems, ref deliveryitems);
            UpdateTakenBy(entity, ref requisitionitems, ref deliveryitems);
            UpdateStockBatches(entity, ref requisitionitems);

            UpdateTrackingKanban<RequisitionKanban, Requisition, RequisitionLink>(entity, e =>
            {
                if (!entity.Archived.Equals(DateTime.MinValue) || entity.TakenBy.IsValid())
                    return KanbanCategory.Complete;
                if (entity.Delivery.IsValid())
                {
                    if (entity.Delivery.Completed != DateTime.MinValue)
                    {
                        return KanbanCategory.Complete;
                    }
                }
                if (!entity.Filled.Equals(DateTime.MinValue))
                    return KanbanCategory.Waiting;
                if (Provider.Query(
                        new Filter<RequisitionItem>(x => x.RequisitionLink.ID).IsEqualTo(entity.ID),
                        new Columns<RequisitionItem>(x => x.ID)
                    ).Rows.Any()
                   )
                    return KanbanCategory.InProgress;
                return KanbanCategory.Open;
            });
        }
        
        protected override void BeforeDelete(Requisition entity)
        {
            UnlinkTrackingKanban<RequisitionKanban, Requisition, RequisitionLink>(entity);
        }
        
        #region Delivery Items

        private void CreateDeliveryItems(Requisition entity, ref IEnumerable<RequisitionItem> requisitionitems,
            ref IEnumerable<DeliveryItem> deliveryitems)
        {
            if (!LoadRequisitionItems(entity, ref requisitionitems))
            {
                Log("CreateDeliveryItems() - no requisition items to update");
                return;
            }

            var updates = new List<DeliveryItem>();
            foreach (var item in requisitionitems)
                updates.Add(item.CreateDeliveryItem(entity));

            if (updates.Any())
                FindSubStore<DeliveryItem>().Save(updates, "Requisition [Filled] flag has been set");

            deliveryitems = updates;
        }

        private void ClearDeliveryItems(Requisition entity, ref IEnumerable<DeliveryItem> deliveryitems)
        {
            if (!LoadDeliveryItems(entity, ref deliveryitems))
            {
                Log("ClearDeliveryItems() - no delivery items to update");
                return;
            }

            if (deliveryitems.Any())
                FindSubStore<DeliveryItem>().Delete(deliveryitems, "Requisition [Filled] flag has been cleared");
            deliveryitems = new List<DeliveryItem>();
        }

        private void UpdateDeliveryItems(Requisition entity, ref IEnumerable<RequisitionItem> requisitionitems,
            ref IEnumerable<DeliveryItem> deliveryitems)
        {
            Log("UpdateDeliveryItems() - starting");


            if (!NeedsUpdating(entity, x => x.Filled))
            {
                Log("UpdateDeliveryItems() - NeedsUpdate() return false");
                return;
            }

            var oldfilled = entity.GetOriginalValue(x => x.Filled);
            var newfilled = entity.Filled;

            // Gone from Blank to Filled -> Create a Batch
            if (oldfilled.IsEmpty() && !newfilled.IsEmpty())
            {
                Log("UpdateDeliveryItems() - Filled has been set");
                ClearDeliveryItems(entity, ref deliveryitems);
                CreateDeliveryItems(entity, ref requisitionitems, ref deliveryitems);
            }
            // Gone from Filled to Blank -> Clear Out the Batch
            else if (newfilled.IsEmpty() && !oldfilled.IsEmpty())
            {
                Log("UpdateDeliveryItems() - Filled has been cleared");
                ClearDeliveryItems(entity, ref deliveryitems);
            }

            // Do nothing - filled flag has been updated, not set or cleared
            Log("UpdateDeliveryItems() - done");
        }

        #endregion

        #region StockMovements

        private void CreateStockMovement(List<StockMovement> updates, Guid employeeid, DateTime date, Guid batchid, Guid productid, Guid locationid,
            Guid styleid, Guid jobid, double qty, IDimensions dimensions, Guid txnid, bool system, string note)
        {
            var movement = new StockMovement();
            movement.Batch.ID = batchid;
            movement.Product.ID = productid;
            movement.Location.ID = locationid;
            movement.Style.ID = styleid;
            movement.Job.ID = jobid;
            movement.Issued = qty < 0.0F ? Math.Abs(qty) : 0.0F;
            movement.Received = qty > 0.0F ? qty : 0.0F;
            movement.Qty = qty;
            movement.Units = qty;
            movement.Dimensions.CopyFrom(dimensions);
            movement.System = system;
            movement.Transaction = txnid;
            movement.Notes = note;
            movement.Date = date;
            movement.Employee.ID = employeeid;
            updates.Add(movement);
        }

        private void CreateStockBatch(Requisition entity, ref IEnumerable<RequisitionItem> items)
        {
            LoadRequisitionItems(entity, ref items);
            if (!items.Any())
            {
                Log("CreateStockBatch() - no items to update!");
                return;
            }

            var batch = new StockMovementBatch
            {
                Type = StockMovementBatchType.Issue,
                TimeStamp = entity.Filled,
                Notes = string.Format("Requisition #{0}", entity.Number)
            };
            batch.Employee.ID = entity.Employee.ID;
            batch.Requisition.ID = entity.ID;
            FindSubStore<StockMovementBatch>().Save(batch, "");

            var updates = new List<StockMovement>();
            foreach (var item in items)
            {
                
                var locationid = item.Location.ID;
                var productid = item.Product.ID;
                var styleid = item.Style.ID;
                var unitsize = item.Dimensions.UnitSize;

                var jobid = entity.JobLink.ID;

                var holdings = Provider.Query<StockHolding>(
                    new Filter<StockHolding>(x => x.Location.ID).IsEqualTo(locationid)
                        .And(x => x.Product.ID).IsEqualTo(productid)
                        .And(x => x.Style.ID).IsEqualTo(styleid)
                        .And(x => x.Dimensions.UnitSize).IsEqualTo(unitsize)
                );
                var holdingrow = holdings.Rows.FirstOrDefault(r => r.Get<StockHolding, Guid>(c => c.Job.ID).Equals(jobid));
                if (holdingrow == null)
                    holdingrow = holdings.Rows.FirstOrDefault(r => r.Get<StockHolding, Guid>(c => c.Job.ID).Equals(Guid.Empty));
                if (holdingrow == null)
                    holdingrow = holdings.Rows.FirstOrDefault();
                Guid holdingjobid = holdingrow != null
                    ? holdingrow.Get<StockHolding, Guid>(c => c.Job.ID)
                    : Guid.Empty;

                var qty = item.Quantity;
                var dimensions = item.Product.Dimensions;

                var txnid = Guid.Empty;
                if (jobid != holdingjobid)
                {
                    txnid = Guid.NewGuid();
                    CreateStockMovement(updates, entity.Employee.ID, DateTime.Now, batch.ID, productid, locationid, styleid, holdingjobid,
                        0.0F - qty, dimensions, txnid, true, string.Format("Requisition #{0} Internal Transfer", entity.Number));
                    CreateStockMovement(updates, entity.Employee.ID, DateTime.Now, batch.ID, productid, locationid, styleid, jobid, qty, dimensions, txnid, true,
                        string.Format("Requisition #{0} Internal Transfer", entity.Number));
                }

                CreateStockMovement(updates, entity.Employee.ID, DateTime.Now, batch.ID, productid, locationid, styleid, jobid, 0.0F - qty, dimensions, txnid,
                    false,
                    string.Format("Requisition #{0}", entity.Number));
            }

            FindSubStore<StockMovement>().Save(updates, "");
        }

        private void ClearStockBatch(Requisition entity)
        {
            Log("ClearStockBatch()");
            var batches = Provider.Query(
                new Filter<StockMovementBatch>(x => x.Requisition.ID).IsEqualTo(entity.ID),
                new Columns<StockMovementBatch>(x => x.ID)
            ).Rows.Select(x => x.ToObject<StockMovementBatch>());
            if (batches.Any())
                FindSubStore<StockMovementBatch>().Delete(batches, "");
        }

        private void UpdateStockBatches(Requisition entity, ref IEnumerable<RequisitionItem> items)
        {
            Log("UpdateStockBatch() - starting");
            if (!NeedsUpdating(entity, x => x.StockUpdated))
                return;

            var oldupdate = entity.GetOriginalValue(x => x.StockUpdated);
            var newupdate = entity.StockUpdated;

            // Gone from Blank to Updated -> Create a Batch
            if (oldupdate.IsEmpty() && !newupdate.IsEmpty())
            {
                Log("UpdateStockBatch() - creating batch");
                ClearStockBatch(entity);
                CreateStockBatch(entity, ref items);
            }
            // Gone from Updated to Blank -> Clear Out the Batch
            else if (newupdate.IsEmpty() && !oldupdate.IsEmpty())
            {
                Log("UpdateStockBatch() - clearing batch");
                ClearStockBatch(entity);
            }

            // Do nothing - Updated flag has been updated, not set or cleared
            Log("UpdateStockBatch() - done");
        }

        #endregion
    }
}