using System;
using System.Collections.Generic;
using System.Linq;
using InABox.Clients;
using InABox.Core;

namespace Comal.Classes
{
    public static class StockHoldingExtensions
    {
        /// <summary>
        /// Create a new stock movement from an <see cref="IStockHolding"/>, copying across the "key" properties;
        /// that is, the job, product, style, location and dimensions.
        /// </summary>
        /// <remarks>
        /// Also sets the <see cref="StockMovement.Date"/> to today.
        /// </remarks>
        /// <param name="holding"></param>
        /// <returns></returns>
        public static StockMovement CreateMovement(this IStockHolding holding)
        {
            var movement = new StockMovement();
            movement.Date = DateTime.Now;
            movement.Job.ID = holding.Job.ID;
            movement.Job.Synchronise(holding.Job);
            movement.Product.ID = holding.Product.ID;
            movement.Product.Synchronise(holding.Product);
            movement.Style.ID = holding.Style.ID;
            movement.Style.Synchronise(holding.Style);
            movement.Location.ID = holding.Location.ID;
            movement.Location.Synchronise(holding.Location);
            movement.Dimensions.CopyFrom(holding.Dimensions);
            return movement;
        }

        public static List<StockHolding> GroupMovements(IEnumerable<StockMovement> movements)
        {
            var grouped = new List<StockHolding>();

            var toGroup = movements.AsList();
            while (toGroup.Count > 0)
            {
                var first = toGroup.First();
                var selected = toGroup.Where(x => x.IsEqualTo(first)).ToList();

                var holding = grouped.FirstOrDefault(x => x.IsEqualTo(first));
                if (holding == null)
                {
                    holding = new StockHolding();
                    holding.Location.CopyFrom(first.Location);
                    holding.Product.CopyFrom(first.Product);
                    holding.Style.CopyFrom(first.Style);
                    holding.Job.CopyFrom(first.Job);
                    holding.Dimensions.CopyFrom(first.Dimensions);
                    grouped.Add(holding);
                }
                holding.Recalculate(selected);

                toGroup.RemoveAll(x => selected.Any(s => s.ID == x.ID));
            }
            return grouped;
        }

        public static bool IsEqualTo(this IStockHolding row1, IStockHolding row2)
        {
            return row1.Product.ID == row2.Product.ID
                   && row1.Location.ID == row2.Location.ID
                   && row1.Job.ID == row2.Job.ID
                   && row1.Style.ID == row2.Style.ID
                   && row1.Dimensions.Unit.ID == row2.Dimensions.Unit.ID
                   && row1.Dimensions.Length.IsEffectivelyEqual(row2.Dimensions.Length)
                   && row1.Dimensions.Width.IsEffectivelyEqual(row2.Dimensions.Width)
                   && row1.Dimensions.Height.IsEffectivelyEqual(row2.Dimensions.Height)
                   && row1.Dimensions.Quantity.IsEffectivelyEqual(row2.Dimensions.Quantity)
                   && row1.Dimensions.Weight.IsEffectivelyEqual(row2.Dimensions.Weight);
        }
        
        public static bool IsEqualTo<T1,T2>(this CoreRow row1, CoreRow row2)
            where T1 : IStockHolding
            where T2 : IStockHolding
        {
            return row1.Get<T1,Guid>(x=>x.Product.ID) == row2.Get<T2,Guid>(x => x.Product.ID)
                   && row1.Get<T1,Guid>(x=>x.Location.ID) == row2.Get<T2,Guid>(x => x.Location.ID)
                   && row1.Get<T1,Guid>(x=>x.Job.ID) == row2.Get<T2,Guid>(x => x.Job.ID)
                   && row1.Get<T1,Guid>(x=>x.Style.ID) == row2.Get<T2,Guid>(x => x.Style.ID)
                   && row1.Get<T1,Guid>(x=>x.Dimensions.Unit.ID) == row2.Get<T2,Guid>(x => x.Dimensions.Unit.ID)
                   && row1.Get<T1,double>(x=>x.Dimensions.Length).IsEffectivelyEqual(row2.Get<T2,double>(x=>x.Dimensions.Length))
                   && row1.Get<T1,double>(x=>x.Dimensions.Width).IsEffectivelyEqual(row2.Get<T2,double>(x=>x.Dimensions.Width))
                   && row1.Get<T1,double>(x=>x.Dimensions.Height).IsEffectivelyEqual(row2.Get<T2,double>(x=>x.Dimensions.Height))
                   && row1.Get<T1,double>(x=>x.Dimensions.Quantity).IsEffectivelyEqual(row2.Get<T2,double>(x=>x.Dimensions.Quantity))
                   && row1.Get<T1,double>(x=>x.Dimensions.Weight).IsEffectivelyEqual(row2.Get<T2,double>(x=>x.Dimensions.Weight));
        }

        public static void Recalculate(this StockHolding holding, IEnumerable<StockMovement> movements)
        {
            movements = movements.AsIList();
            var units = movements.Sum(x => x.Units);
            var cost = movements.Select(x => x.Units * x.Cost).Sum();
            var available = movements.Where(x => x.JobRequisitionItem.ID == Guid.Empty).Sum(x => x.Units);
            holding.Units = units;
            holding.Available = available;
            holding.Qty = movements.Sum(x => x.Units * x.Dimensions.Value);
            holding.Value = cost;

            holding.AverageValue = units.IsEffectivelyEqual(0.0F) ? 0.0d : cost / units;
            holding.Weight = holding.Qty * holding.Dimensions.Weight;
        }
        
        public static IEnumerable<JobRequisitionItem> LoadRequisitionItems(this StockHolding holding, bool alwaysshowunallocated = false, Columns<JobRequisitionItem>? columns = null)
        {
            columns ??= Columns.None<JobRequisitionItem>();
            columns.Add(x => x.ID)
                .Add(x => x.Product.ID)
                .Add(x => x.Style.ID)
                .AddDimensionsColumns(x => x.Dimensions)
                .Add(x => x.Job.ID)
                .Add(x => x.Job.JobNumber)
                .Add(x => x.Job.Name)
                .Add(x => x.Requisition.Number)
                .Add(x => x.Requisition.Description)
                .Add(x => x.Qty);

            var items = new Client<JobRequisitionItem>().Query(
                    new Filter<JobRequisitionItem>(x => x.ID).InQuery(StockHolding.GetFilter(holding), x => x.JobRequisitionItem.ID),
                    columns)
                .ToObjects<JobRequisitionItem>()
                .Where(x=>x.Product.ID == holding.Product.ID && x.Style.ID == holding.Style.ID && x.Dimensions.Equals(holding.Dimensions));
            if (holding.Available > 0 || alwaysshowunallocated)
            {
                var requi = new JobRequisitionItem() { Qty = holding.Available };
                requi.Requisition.Description = "Unallocated Items";
                items = CoreUtils.One(requi).Concat(items);
            }

            return items;
        }

        public static IEnumerable<StockMovement> AdjustValue(this StockHolding holding, double unitvalue, StockMovementBatch batch)
        {
            List<StockMovement> _result = new List<StockMovement>();
            var movements = Client.Query(
                new Filter<StockMovement>(x => x.Location.ID).IsEqualTo(holding.Location.ID)
                    .And(x=>x.Product.ID).IsEqualTo(holding.Product.ID)
                    .And(x => x.Style.ID).IsEqualTo(holding.Style.ID)
                    .And(x => x.Dimensions).DimensionEquals(holding.Dimensions)
                    .And(x => x.Job.ID).IsEqualTo(holding.Job.ID),
                Columns.Required<StockMovement>().Add(x=>x.Units)
            ).Rows.ToObjects<StockMovement>().ToArray();
            var _allocations = movements.GroupBy(x => x.JobRequisitionItem.ID);
            foreach (var _allocation in _allocations)
            {
                var _units = _allocation.Sum(x => x.Units);
                if (!_units.IsEffectivelyEqual(0.0))
                {
                    var _transout = holding.CreateMovement();
                    _transout.Employee.ID = batch.Employee.ID;
                    _transout.Issued = _units;
                    _transout.Cost = holding.AverageValue;
                    _transout.Type = StockMovementType.TransferOut;
                    _transout.JobRequisitionItem.ID = _allocation.Key;
                    _transout.Batch.ID = batch.ID;
                    _transout.Notes = $"Adjusting Average Value from ${holding.AverageValue:F2} to ${unitvalue:F2}";
                    _result.Add(_transout);

                    var _transin = holding.CreateMovement();
                    _transin.Date = _transout.Date.AddTicks(1);
                    _transout.Employee.ID = batch.Employee.ID;
                    _transin.Received = _units;
                    _transin.Cost = unitvalue;
                    _transin.Type = StockMovementType.TransferIn;
                    _transin.Transaction = _transout.Transaction;
                    _transin.JobRequisitionItem.ID = _allocation.Key;
                    _transin.Batch.ID = batch.ID;
                    _transin.Notes = $"Adjusting Average Value from ${holding.AverageValue:F2} to ${unitvalue:F2}";
                    _result.Add(_transin);
                }
            }

            return _result;
        }

        public static Dictionary<(Guid product, Guid style, Guid location, Guid job, StockDimensions dimensions), StockHolding> LoadStockHoldings(IEnumerable<IStockHolding> mvts, Columns<StockHolding> columns, Dictionary<(Guid product, Guid style, Guid location, Guid job, StockDimensions dimensions), StockHolding>? holdings = null, IQueryProvider<StockHolding>? query = null)
        {
            query ??= Client<StockHolding>.Provider;

            columns.Add(x => x.ID);
            columns.Add(x => x.Product.ID);
            columns.Add(x => x.Location.ID);
            columns.Add(x => x.Style.ID);
            columns.Add(x => x.Job.ID);
            columns.AddDimensionsColumns(x => x.Dimensions, Dimensions.ColumnsType.Local);

            if(holdings != null)
            {
                mvts = mvts.Where(mvt =>
                {
                    var key = (mvt.Product.ID, mvt.Style.ID, mvt.Location.ID, mvt.Job.ID, mvt.Dimensions);
                    return !holdings.ContainsKey(key);
                }).ToArray();
            }
            else
            {
                holdings = new Dictionary<(Guid product, Guid style, Guid location, Guid job, StockDimensions dimensions), StockHolding>();
            }

            var productIDs = mvts.Select(x => x.Product.ID).Distinct().ToArray();
            var locationIDs = mvts.Select(x => x.Location.ID).Distinct().ToArray();
            var styleIDs = mvts.Select(x => x.Style.ID).Distinct().ToArray();
            var jobIDs = mvts.Select(x => x.Job.ID).Distinct().ToArray();

            var newHoldings = query.Query(new Filter<StockHolding>(x => x.Product.ID).InList(productIDs)
                    .And(x => x.Location.ID).InList(locationIDs)
                    .And(x => x.Style.ID).InList(styleIDs)
                    .And(x => x.Job.ID).InList(jobIDs),
                columns
            ).ToObjects<StockHolding>();
            foreach(var holding in newHoldings)
            {
                holdings[(holding.Product.ID, holding.Style.ID, holding.Location.ID, holding.Job.ID, holding.Dimensions)] = holding;
            }

            return holdings;
        }
        
    }
}