using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using InABox.Core;
using PRSClasses;

namespace Comal.Classes
{

    
    public class StockHoldingLastStocktake : CoreAggregate<StockHolding, StockMovement, DateTime>
    {
        public override Expression<Func<StockMovement, DateTime>> Aggregate => x => x.Date;

        public override Filter<StockMovement> Filter => new Filter<StockMovement>(x => x.Type)
            .IsEqualTo(StockMovementType.StockTake);

        public override Dictionary<Expression<Func<StockMovement, object>>, Expression<Func<StockHolding, object>>> Links =>
            new Dictionary<Expression<Func<StockMovement, object>>, Expression<Func<StockHolding, object>>>()
            {
                { StockMovement => StockMovement.Product.ID, StockHolding => StockHolding.Product.ID },
                { StockMovement => StockMovement.Location.ID, StockHolding => StockHolding.Location.ID },
                { StockMovement => StockMovement.Style.ID, StockHolding => StockHolding.Style.ID },
                { StockMovement => StockMovement.Job.ID, StockHolding => StockHolding.Job.ID },
                { StockMovement => StockMovement.Dimensions.Unit.ID, StockHolding => StockHolding.Dimensions.Unit.ID },
                { StockMovement => StockMovement.Dimensions.UnitSize, StockHolding => StockHolding.Dimensions.UnitSize },
                
            };

        public override AggregateCalculation Calculation => AggregateCalculation.Maximum;
    }
    
    [UserTracking(typeof(StockMovement))]
    [Unrecoverable]
    public class StockHolding : StockEntity, IRemotable, IPersistent, IOneToMany<StockLocation>, IOneToMany<Product>, 
        IStockHolding, ILicense<WarehouseLicense>
    {
        
        [Editable(Editable.Disabled)]
        [EditorSequence(1)]
        public StockLocationLink Location { get; set; }
        
        private class ProductLookupGenerator : LookupDefinitionGenerator<Product, StockHolding>
        {
            public override Filter<Product>? DefineFilter(StockHolding[] items)
                => LookupFactory.DefineFilter<Product>().And(x => x.NonStock).IsEqualTo(false);
        }
        [Editable(Editable.Disabled)]
        [EditorSequence(2)]
        [LookupDefinition(typeof(ProductLookupGenerator))]
        public override ProductLink Product { get; set; }
        
        [DimensionsEditor(typeof(StockDimensions), AllowEditingUnit = false)]
        [Editable(Editable.Disabled)]
        [EditorSequence(3)]
        public override StockDimensions Dimensions { get; set; }

        [Editable(Editable.Disabled)]
        [EditorSequence(4)]
        public ProductStyleLink Style { get; set; }
        
        [Editable(Editable.Disabled)]
        [EditorSequence(4)]
        public JobLink Job { get; set; }
        
        [DoubleEditor(Editable = Editable.Disabled, Summary = Summary.Sum)]
        [EditorSequence(5)]
        public double Units { get; set; }
        
        [DoubleEditor(Editable = Editable.Disabled, Summary = Summary.Sum)]
        [EditorSequence(6)]
        public double Qty { get; set; }
        
        [DoubleEditor(Editable = Editable.Disabled, Summary = Summary.Sum)]
        [EditorSequence(7)]
        public double Weight { get; set; }
        
        [DoubleEditor(Editable = Editable.Disabled, Summary = Summary.Sum)]
        [EditorSequence(8)]
        public double Value { get; set; }
        
        [DoubleEditor(Editable = Editable.Disabled)]
        [EditorSequence(9)]
        public double AverageValue { get; set; }
        
        [DoubleEditor(Editable = Editable.Disabled, Summary = Summary.Sum)]
        [EditorSequence(10)]
        public double Available { get; set; }
        
        [Aggregate(typeof(StockHoldingLastStocktake))]
        [DateEditor(Editable = Editable.Disabled)]
        [EditorSequence(11)]
        public DateTime LastStockTake { get; set; }
        
        public static Column<IStockHolding>[] Columns => new Column<IStockHolding>[]
        {
            new Column<IStockHolding>(x => x.Job.ID),
            new Column<IStockHolding>(x => x.Location.ID),
            new Column<IStockHolding>(x => x.Product.ID),
            new Column<IStockHolding>(x => x.Style.ID),
            new Column<IStockHolding>(x => x.Dimensions.Unit.ID),
            new Column<IStockHolding>(x => x.Dimensions.Quantity),
            new Column<IStockHolding>(x => x.Dimensions.Length),
            new Column<IStockHolding>(x => x.Dimensions.Width),
            new Column<IStockHolding>(x => x.Dimensions.Height),
            new Column<IStockHolding>(x => x.Dimensions.Weight),
        };
        
        public static Filter<StockMovement>? GetFilter(IStockHolding holding)
        {
            var filter = new Filters<StockMovement>();
        
            foreach(var column in Columns)
            {
                filter.Add(new Filter<StockMovement>(column.Cast<StockMovement>()).IsEqualTo(CoreUtils.GetPropertyValue(holding, column.Property)));
            }
        
            return filter.Combine();
        }
    }

    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>
        /// <param name="holding"></param>
        /// <returns></returns>
        public static StockMovement CreateMovement(this IStockHolding holding)
        {
            var movement = new StockMovement();
            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 IEnumerable<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.ID = first.Location.ID;
                    holding.Product.ID = first.Product.ID;
                    holding.Style.ID = first.Style.ID;
                    holding.Job.ID = first.Job.ID;
                    holding.Dimensions.CopyFrom(first.Dimensions);
                }
                holding.Recalculate(selected);

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

        public static bool IsEqualTo(this IStockHolding h1, IStockHolding h2)
        {
            return h1.Product.ID == h2.Product.ID
                && h1.Location.ID == h2.Location.ID
                && h1.Job.ID == h2.Job.ID
                && h1.Style.ID == h2.Style.ID
                && h1.Dimensions.Unit.ID == h2.Dimensions.Unit.ID
                && h1.Dimensions.Length.IsEffectivelyEqual(h2.Dimensions.Length)
                && h1.Dimensions.Width.IsEffectivelyEqual(h2.Dimensions.Width)
                && h1.Dimensions.Height.IsEffectivelyEqual(h2.Dimensions.Height)
                && h1.Dimensions.Quantity.IsEffectivelyEqual(h2.Dimensions.Quantity)
                && h1.Dimensions.Weight.IsEffectivelyEqual(h2.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;
        }
    }
    
}