using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using Comal.Classes;
using HarfBuzzSharp;
using InABox.Core;
using InABox.Mobile;
using Xamarin.CommunityToolkit.ObjectModel;
using Xamarin.Forms;

namespace PRS.Mobile
{
    public enum StockTransactionType
    {
        Transfer,
        Issue,
        Receive,
        StockTake
    }

    public enum StockTransactionView
    {
        Source,
        Target
    }

    public enum StockTransactionProperty
    {
        Location,
        Style,
        Job
    }
    
    public class StockTransactionHolding : BindableObject
    {
        public StockHoldingShell? Shell { get; set; }
        public Guid LocationID { get; set; }
        public String LocationCode { get; set; }
        public String LocationDescription { get; set; }
        public String LocationDisplay => LocationID == Guid.Empty ? "" : $"{LocationCode}: {LocationDescription}";
        
        public Guid StyleID { get; set; }
        public String StyleCode { get; set; }
        public String StyleDescription { get; set; }
        public String StyleDisplay => StyleID == Guid.Empty ? "" : $"{StyleCode}: {StyleDescription}";
        
        public Guid JobID { get; set; }
        public String JobNumber { get; set; }
        public String JobName { get; set; }
        public String JobDisplay => JobID == Guid.Empty ? "" : $"{JobNumber}: {JobName}";
        public double Units { get; set; }

        public bool HasAllocations => !(Shell?.Units ?? 0.0).IsEffectivelyEqual(Shell?.Available ?? 0.0);
        
        public StockTransactionHolding(StockHoldingShell? shell)
        {
            Shell = shell;
            LocationID = shell?.LocationID ?? Guid.Empty;
            LocationCode = shell?.LocationCode ?? string.Empty;
            LocationDescription = shell?.LocationDescription ?? string.Empty;
            StyleID = shell?.StyleID ?? Guid.Empty;
            StyleCode = shell?.StyleCode ?? string.Empty;
            StyleDescription = shell?.StyleDescription ?? string.Empty;
            JobID = shell?.JobID ?? Guid.Empty;
            JobNumber = shell?.JobNumber ?? string.Empty;
            JobName = shell?.JobName ?? string.Empty;
            Units = shell?.Units ?? 0.0d;
        }
        
    }

    public class StockTransactionAllocation : BindableObject
    {
        public Guid ID { get; set; }
        
        public Guid JobID { get; set; }
        
        public String Description { get; set; }
        
        public double Quantity { get; set; }
        
        public double Maximum { get; set; }
        
    }
    
    public class StockTransaction : BindableObject
    {
        private double _dimensionsQuantity;
        private double _dimensionsLength;
        private double _dimensionsWidth;
        private double _dimensionsHeight;
        private double _dimensionsWeight;

        public StockTransactionType Type { get; set; }
        
        public Guid TransactionID { get; private set; }
        
        public Guid EmployeeID { get; private set; }

        public Guid ProductID { get; set; }
        
        public String ProductCode { get; set; }
        
        public String ProductName { get; set; }

        public String ProductDisplay => ProductID == Guid.Empty ? "" : $"{ProductCode}: {ProductName}"; 
        
        public Guid ImageID { get; set; }
        
        public byte[]? Image { get; set; }
        
        public Guid DimensionsUnitID { get; set; }

        public double DimensionsQuantity
        {
            get => _dimensionsQuantity;
            set
            {
                _dimensionsQuantity = value; 
                CalculateDimensions();
            }
        }

        public double DimensionsLength
        {
            get => _dimensionsLength;
            set
            {
                _dimensionsLength = value; 
                CalculateDimensions();
            }
        }

        public double DimensionsWidth
        {
            get => _dimensionsWidth;
            set
            {
                _dimensionsWidth = value;
                CalculateDimensions();
            }
        }

        public double DimensionsHeight
        {
            get => _dimensionsHeight;
            set
            {
                _dimensionsHeight = value;
                CalculateDimensions();
            }
        }

        public double DimensionsWeight
        {
            get => _dimensionsWeight;
            set
            {
                _dimensionsWeight = value;
                CalculateDimensions();
            }
        }

        public String DimensionsUnitSize { get; set; }
        
        public double DimensionsValue { get; set; }
        
        public double Cost { get; set; }

        public StockTransactionAllocation[]? Allocations { get; set; }
        
        public double Quantity => Allocations?.Aggregate(0.0, (t, a) => t += a.Quantity) ?? 0.0;

        public void RefreshQuantity() => OnPropertyChanged(nameof(Quantity));
        
        public bool HasAllocations => Allocations?.Any(x => x.ID != Guid.Empty) ?? false;
        
        public StockTransactionHolding Source { get; private set; }
        
        public StockTransactionHolding Target { get; private set; }

        public bool LocationChanged => (Source?.LocationID ?? Guid.Empty) != (Target?.LocationID ?? Guid.Empty);
        public bool StyleChanged => (Source?.StyleID ?? Guid.Empty) != (Target?.StyleID ?? Guid.Empty);
        public bool JobChanged => (Source?.JobID ?? Guid.Empty) != (Target?.JobID ?? Guid.Empty);

        public StockTransaction(StockTransactionType type, StockHoldingShell? source, StockHoldingShell? target)
        {
            var shell = source ?? target;
            Type = type;
            TransactionID = Guid.NewGuid();
            EmployeeID = App.Data.Me.ID;
            
            ProductID = shell?.ProductID ?? Guid.Empty;
            ProductCode = shell?.ProductCode ?? string.Empty;
            ProductName = shell?.ProductName ?? string.Empty;
            ImageID = shell?.ImageID ?? Guid.Empty;
            Image = shell?.Image ?? new byte[] { };
            DimensionsUnitID = shell?.DimensionsUnitID ?? Guid.Empty;
            DimensionsQuantity = shell?.DimensionsQuantity ?? 0.0;
            DimensionsLength = shell?.DimensionsLength ?? 0.0;
            DimensionsWidth = shell?.DimensionsWidth ?? 0.0;
            DimensionsHeight = shell?.DimensionsHeight ?? 0.0;
            DimensionsWeight = shell?.DimensionsWeight ?? 0.0;
            DimensionsUnitSize = shell?.DimensionsUnitSize ?? string.Empty;
            DimensionsValue = shell?.DimensionsValue ?? 0.0;
            Cost = shell?.AverageCost ?? 0.0;
            
            Source = new StockTransactionHolding(source);
            Source.PropertyChanged += (sender, args) => OnPropertyChanged(nameof(Source));
            Target = new StockTransactionHolding(target);
            Target.PropertyChanged += (sender, args) => OnPropertyChanged(nameof(Target));

        }
        
        private void  CalculateDimensions()
        {
            var dimensions = App.Data.ProductDimensionUnits.FirstOrDefault(x => x.ID == DimensionsUnitID);
            Dictionary<string, object?> variables = new Dictionary<string, object?>();

            variables["Length"] = DimensionsLength;
            variables["Width"] = DimensionsWidth;
            variables["Height"] = DimensionsHeight;
            variables["Quantity"] = DimensionsQuantity;
            variables["Weight"] = DimensionsHeight;

            if (! String.IsNullOrWhiteSpace(dimensions?.Format))
                DimensionsUnitSize = new CoreExpression(dimensions.Format).Evaluate(variables)?.ToString() ?? string.Empty;

            if (!String.IsNullOrWhiteSpace(dimensions?.Formula))
            {
                var value = new CoreExpression(dimensions.Format).Evaluate(variables)?.ToString() ?? "0.0";
                DimensionsValue = double.TryParse(value, out double val)
                    ? val
                    : 0.0;
            }
            
        }


        public string Display(StockTransactionView? view = null)
        {

            List<String> results = new List<string>();
            
            if ((Source?.LocationID ?? Guid.Empty) != (Target?.LocationID ?? Guid.Empty))
            {
                string location = Type switch
                {
                    StockTransactionType.Issue => "Issued",
                    StockTransactionType.Receive => "Received",
                    _ => "Transferred"
                };
                string fromlocation = "";
                string tolocation = "";

                if ((view == null) || (view == StockTransactionView.Target))
                    fromlocation = (Source?.LocationID ?? Guid.Empty) != Guid.Empty
                        ? $" From {Source?.LocationCode ?? "--"}"
                        : " From --";
                if ((view == null) || (view == StockTransactionView.Source))
                    tolocation = (Target?.LocationID ?? Guid.Empty) != Guid.Empty
                        ? $" To {Target?.LocationCode ?? "--"}"
                        : " To --";
                results.Add($"{location}{fromlocation}{tolocation}");
            }

            if ((Source?.StyleID ?? Guid.Empty) != (Target?.StyleID ?? Guid.Empty))
            {
                string fromstyle = "";
                string tostyle = "";
                
                if ((view == null) || (view == StockTransactionView.Target))
                    fromstyle = (Source?.StyleID ?? Guid.Empty) != Guid.Empty
                        ? $" From {Source?.StyleCode ?? "(none)"}"
                        : " From (none)";
                
                if ((view == null) || (view == StockTransactionView.Source))
                    tostyle = (Target?.StyleID ?? Guid.Empty) != Guid.Empty
                        ? $" To {Target?.StyleCode ?? "(none)"}"
                        : " To (none)";
                
                results.Add($"Changed Style{fromstyle}{tostyle}");
            }
            
            if ((Source?.JobID ?? Guid.Empty) != (Target?.JobID ?? Guid.Empty))
            {
                string fromjob = "";
                string tojob = "";

                if ((view == null) || (view == StockTransactionView.Target))
                    fromjob = (Source?.JobID ?? Guid.Empty) != Guid.Empty
                        ? $" From {Source?.JobNumber ?? "(none)"}"
                        : " From (none)";
                
                if ((view == null) || (view == StockTransactionView.Source))
                    tojob = (Target?.JobID ?? Guid.Empty) != Guid.Empty
                        ? $" To {Target?.JobNumber ?? "(none)"}"
                        : " To (none)";
                
                results.Add($"Changed Job{fromjob}{tojob}");
            }
            
            return String.Join("\n", results);
            
        }
        
    }
    
    public class StockTransactionImage : BindableObject
    {
        public MobileDocument Document { get; private set; }
        public byte[] Thumbnail { get; set; }

        public StockTransactionImage(MobileDocument document, byte[] thumbnail)
        {
            Document = document;
            Thumbnail = thumbnail;
        }
        
    }

    public class StockTransactions : ObservableRangeCollection<StockTransaction>
    {
        private enum TransactionDirection
        {
            Issue,
            Receive
        }
        public void ProcessTransactions(StockMovementModel model, Guid batchid)
        {

            void CreateMovement(
                StockMovementType type,
                StockTransaction transaction,
                Guid locationid,
                Guid styleid,
                Guid jobid,
                DateTime timestamp,
                TransactionDirection direction,
                Action<StockTransaction, StockTransactionAllocation, StockMovementShell>? oncreate = null 
                )
            {

                foreach (var allocation in transaction.Allocations)
                {
                    var movement = model.AddItem();
                    movement.BatchID = batchid;
                    movement.Date = timestamp;
                    movement.Type = type;
                    movement.TransactionID = transaction.TransactionID;
                    movement.ProductID = transaction.ProductID;
                    movement.DimensionsUnitID = transaction.DimensionsUnitID;
                    movement.DimensionsQuantity = transaction.DimensionsQuantity;
                    movement.DimensionsLength = transaction.DimensionsLength;
                    movement.DimensionsWidth = transaction.DimensionsWidth;
                    movement.DimensionsHeight = transaction.DimensionsHeight;
                    movement.DimensionsWeight = transaction.DimensionsWeight;
                    movement.DimensionsValue = transaction.DimensionsValue;
                    movement.DimensionsUnitSize = transaction.DimensionsUnitSize;
                    movement.LocationID = locationid;
                    movement.StyleID = styleid;
                    movement.JobID = jobid;
                    movement.RequisitionItemID = allocation.ID;
                    movement.Received = direction == TransactionDirection.Receive ? allocation.Quantity : 0.0F;
                    movement.Issued = direction == TransactionDirection.Issue ? allocation.Quantity : 0.0F;
                    movement.Cost = transaction.Cost;
                    movement.EmployeeID = transaction.EmployeeID;
                    oncreate?.Invoke(transaction, allocation, movement);
                }
            }
            
            var now = DateTime.Now;
            foreach (var transaction in this)
            {
                if (transaction.Type == StockTransactionType.Receive)
                {
                    CreateMovement(
                        StockMovementType.Receive,
                        transaction,
                        transaction.Target.LocationID,
                        transaction.Target.StyleID,
                        transaction.Target.JobID,
                        now,
                        TransactionDirection.Receive
                    );
                }
                else if (transaction.Type == StockTransactionType.Issue)
                {
                    if (transaction.Source.StyleID != transaction.Target.StyleID ||
                        transaction.Source.JobID != transaction.Target.JobID)
                    {
                        CreateMovement(
                            StockMovementType.TransferOut,
                            transaction,
                            transaction.Source.LocationID,
                            transaction.Source.StyleID,
                            transaction.Source.JobID,
                            now,
                            TransactionDirection.Issue);
                        
                        CreateMovement(
                            StockMovementType.TransferIn,
                            transaction,
                            transaction.Source.LocationID,
                            transaction.Target.StyleID,
                            transaction.Target.JobID,
                            now,
                            TransactionDirection.Receive);
                    }

                    CreateMovement(
                        StockMovementType.Issue,
                        transaction,
                        transaction.Source.LocationID,
                        transaction.Target.StyleID,
                        transaction.Target.JobID,
                        now,
                        TransactionDirection.Issue);
                }
                else if (transaction.Type == StockTransactionType.Transfer)
                {
                    CreateMovement(
                        StockMovementType.TransferOut,
                        transaction,
                        transaction.Source.LocationID,
                        transaction.Source.StyleID,
                        transaction.Source.JobID,
                        now,
                        TransactionDirection.Issue);
                    CreateMovement(
                        StockMovementType.TransferIn,
                        transaction,
                        transaction.Target.LocationID,
                        transaction.Target.StyleID,
                        transaction.Target.JobID,
                        now,
                        TransactionDirection.Receive);
                }
                else if (transaction.Type == StockTransactionType.StockTake)
                {
                    CreateMovement(
                        StockMovementType.StockTake,
                        transaction,
                        transaction.Target.LocationID,
                        transaction.Target.StyleID,
                        transaction.Target.JobID,
                        now,
                        transaction.Quantity > 0 ? TransactionDirection.Receive : TransactionDirection.Issue,
                        (t, a, m) =>
                        {
                            var srcAlloc = t.Source.Shell.Allocations.FirstOrDefault(x => x.ID == a.ID);
                            m.Issued = Math.Max(0, (srcAlloc?.Quantity ?? t.Source.Units) - a.Quantity);
                            m.Received = Math.Max(0, a.Quantity - (srcAlloc?.Quantity ?? t.Source.Units));
                            m.Notes = m.Issued.IsEffectivelyEqual(0.0F) && m.Received.IsEffectivelyEqual(0.0F) 
                                ? $"Correct Quantity Confirmed"
                                : $"Quantity Adjusted from {(srcAlloc?.Quantity ?? t.Source.Units):F2} to {a.Quantity:F2}";
                            m.Balance = a.Quantity;
                        }

                    );
                }
            }
        }

        public IEnumerable<StockTransaction> Get(StockHoldingShell shell)
        {
            bool IsHoldingReferenced(StockTransactionHolding holding) =>
                holding.LocationID == shell.LocationID
                && holding.StyleID == shell.StyleID
                && holding.JobID == shell.JobID;
            
            var results = this.Where(x => x.ProductID == shell.ProductID
                && String.Equals(x.DimensionsUnitSize, shell.DimensionsUnitSize)
                && (IsHoldingReferenced(x.Source) || IsHoldingReferenced(x.Target))).ToArray();

            return results;
        }

        
    }
    
}