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

namespace Comal.Classes
{
    
    public class StockLocationHoldings : CoreAggregate<StockLocation, StockHolding, Guid>
    {
        public override Expression<Func<StockHolding, Guid>> Aggregate => x => x.Product.ID;
        
        public override Dictionary<Expression<Func<StockHolding, object>>, Expression<Func<StockLocation, object>>> Links =>
            new Dictionary<Expression<Func<StockHolding, object>>, Expression<Func<StockLocation, object>>>()
            {
                { StockHolding => StockHolding.Location.ID, StockLocation => StockLocation.ID },
            };
    
        public override AggregateCalculation Calculation => AggregateCalculation.Count;
    }

    public enum StockTakeFrequency
    {
        Never,
        Daily,
        Weekly,
        Fortnightly,
        Monthly,
        Quarterly,
        TwiceYearly,
        Yearly
    }
    
    [UserTracking(typeof(StockMovement))]
    public class StockLocation : Entity, IRemotable, IPersistent, IStockLocation, ILicense<WarehouseLicense>, IExportable, IImportable
    {
        
        
        [UniqueCodeEditor(Visible = Visible.Default, Editable = Editable.Enabled)]
        [EditorSequence(1)]
        public string Code { get; set; }

        [TextBoxEditor]
        [EditorSequence(2)]
        public string Description { get; set; }
        
        [EntityRelationship(DeleteAction.SetNull)]
        [EditorSequence(3)]
        public StockWarehouseLink Warehouse { get; set; }

        private class StockAreaLookup : LookupDefinitionGenerator<StockArea, StockLocation>
        {
            public override Filter<StockArea> DefineFilter(StockLocation[] items)
            {
                var ids = items.Select(x => x.Warehouse.ID).Distinct().ToArray();
                if (ids.Length == 1)
                    return new Filter<StockArea>(x => x.Warehouse.ID).IsEqualTo(ids[0]).And(x => x.Active).IsEqualTo(true);
                return new Filter<StockArea>(x => x.ID).IsEqualTo(CoreUtils.FullGuid);
            }

            public override Columns<StockLocation> DefineFilterColumns()
                => new Columns<StockLocation>(x => x.Warehouse.ID);
        }
        [LookupDefinition(typeof(StockAreaLookup))]
        [EntityRelationship(DeleteAction.SetNull)]
        [EditorSequence(4)]
        public StockAreaLink Area { get; set; }
        
        
        [EditorSequence(5)]
        public JobLink Job { get; set; }

        /// <summary>
        ///     Is the location a "shelf" (ie permanent) or "pack" (ie transient)
        /// </summary>
        [EnumLookupEditor(typeof(StockLocationType))]
        [EditorSequence(6)]
        public StockLocationType Type { get; set; }
        
        /// <summary>
        ///     Is the Stock Location Active?
        /// </summary>
        [EditorSequence(7)]
        public bool Active { get; set; }

        /// <summary>
        ///     Mark this location as the default receival location for the warehouse
        /// </summary>
        [EditorSequence(8)]
        public bool Default { get; set; }

        /// <summary>
        ///     Mark this location as a favourite which shows up in Timebench Transfer module for quick selection
        /// </summary>
        [EditorSequence(9)]
        public bool Favourite { get; set; } = false;
        
        [Aggregate(typeof(StockLocationHoldings))]
        [DoubleEditor(Editable = Editable.Hidden)]
        [EditorSequence(10)]
        public double Holdings { get; set; }
        

        [DateEditor] 
        [EditorSequence("Stocktake",1)]
        public DateTime LastStocktake { get; set; } = DateTime.MinValue;

        [EnumLookupEditor(typeof(StockTakeFrequency))]
        [EditorSequence("Stocktake",2)]
        public StockTakeFrequency StocktakeFrequency { get; set; } = StockTakeFrequency.Never;
        
        [DateEditor] 
        [EditorSequence("Stocktake",3)] 
        public DateTime NextStocktake { get; set; } = DateTime.MaxValue;

        [EditorSequence("Stocktake",4)] 
        [DateEditor] 
        public DateTime CurrentStocktake { get; set; } = DateTime.MinValue;

        private static DateTime CalculateNextStockTake(DateTime last, StockTakeFrequency frequency)
        {

            DateTime CheckDate(DateTime date, Func<DateTime> action) => date.IsEmpty() ? DateTime.Today : action();
            
            return frequency switch
            {
                StockTakeFrequency.Daily => CheckDate(last,() => last.AddDays(1)),
                StockTakeFrequency.Weekly => CheckDate(last,() => last.AddDays(1)),
                StockTakeFrequency.Fortnightly => CheckDate(last,() => last.AddDays(1)),
                StockTakeFrequency.Monthly => CheckDate(last,() => last.AddMonths(1)),
                StockTakeFrequency.Quarterly => CheckDate(last,() => last.AddMonths(3)),
                StockTakeFrequency.TwiceYearly => CheckDate(last,() => last.AddMonths(6)),
                StockTakeFrequency.Yearly => CheckDate(last,() => last.AddYears(1)),
                _ => DateTime.MinValue
            };
        }

        protected override void DoPropertyChanged(string name, object? before, object? after)
        {
            base.DoPropertyChanged(name, before, after);
            if (String.Equals(name, nameof(LastStocktake)))
                NextStocktake = CalculateNextStockTake((DateTime)(after ?? DateTime.MinValue), StocktakeFrequency);
            else if (String.Equals(name, nameof(StocktakeFrequency)))
                NextStocktake = CalculateNextStockTake(LastStocktake, (StockTakeFrequency)(after ?? StockTakeFrequency.Never));
        }
    }
}