using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Linq.Expressions;
using System.Threading.Tasks;
using Comal.Classes;
using InABox.Clients;
using InABox.Core;
using Xamarin.Forms;
using XF.Material.Forms.UI;
using XF.Material.Forms.UI.Dialogs;

namespace PRS.Mobile
{
    public delegate void SaveHoldingEvent(StockHolding holding, Document image);

    public partial class NewHoldingPage 
    {

        public event SaveHoldingEvent OnSaveHolding;
        bool firstLoad = true;
        private Product _product = null;
        private Document _image = null;

        private ProductStyle _style = null;

        private Job _job = null;

        private ProductUOM _uom = null;

        private double _unitsize = 1.0F;

        private async Task<bool> CheckData()
        {
            if (_product == null)
            {
                await MaterialDialog.Instance.AlertAsync("Please select a Product before continuing!");
                return false;
            }
            if (_style == null)
            {
                await MaterialDialog.Instance.AlertAsync("Please select a Style before continuing!");
                return false;
            }
            if (_uom == null)
            {
                await MaterialDialog.Instance.AlertAsync("Please select a Unit Size before continuing!");
                return false;
            }
            if (_unitsize <= 0.0F)
            {
                await MaterialDialog.Instance.AlertAsync("Unit Size must be greater than zero!");
                return false;
            }
            return true;
        }

        public NewHoldingPage(Job job)
        {
            firstLoad = true;
            try 
            {
                _job = new Job();
                _job.ID = job.ID;
                _job.JobNumber = job.JobNumber;
                _job.Name = job.Name;
            } 
            catch { }
            
            InitializeComponent();
            ToolbarItems.Clear();
            ToolbarItems.Add(new ToolbarItem("Save", "", () =>
            {

                if (!CheckData().Result)
                    return;

                StockHolding holding = new StockHolding();
                holding.Product.ID = _product.ID;
                holding.Product.Code = _product.Code;
                holding.Product.Name = _product.Name;
                holding.Product.Image.ID = _product.Image.ID;
                holding.Style.ID = _style.ID;
                holding.Style.Code = _style.Code;
                holding.Style.Description = _style.Description;
                holding.Job.ID = _job != null ? _job.ID : Guid.Empty;
                holding.Job.JobNumber = _job != null ? _job.JobNumber : "";
                holding.Job.Name = _job != null ? _job.Name : "";
                
                OnSaveHolding?.Invoke(holding, _image);
                Navigation.PopAsync();
            }));
            if(_job.ID != Guid.Empty) RefreshPage();
            firstLoad = false;
        }

        protected override void OnAppearing()
        {
            base.OnAppearing();
            if(!firstLoad) RefreshPage();
        }

        private void UpdateLabel<T>(MaterialLabel label, T item, params Expression<Func<T,String>>[] values)
        {
            List<String> data = new List<string>();
            if (item != null)
            {
                foreach (var value in values)
                    data.Add(value.Compile().Invoke(item));
            }
            label.Text = String.Join(": ",data);
            label.IsVisible = !String.IsNullOrWhiteSpace(label.Text);
        }

        void RefreshPage()
        {

            ImageSource source = _image != null ? ImageSource.FromStream(() => new MemoryStream(_image.Data)) : null;
            Image.Source = source;
            NoImage.IsVisible = (_product != null) && (_image == null);
            Image.IsVisible = (_product != null) && (_image != null);

            UpdateLabel<Product>(ProductCode, _product, x => x.Code);
            UpdateLabel<Product>(ProductDescription, _product, x => x.Name);
            UpdateLabel<ProductStyle>(StyleDescription, _style, x => x.Description);
            UpdateLabel<Job>(Job, _job, x => x.JobNumber, x => x.Name);
            UpdateLabel<ProductUOM>(UnitCode, _uom, x => x.Code);
            Size.Text = _unitsize.ToString();
        }

        void SelectProduct_Clicked(System.Object sender, System.EventArgs e)
        {
            GenericSelectionPage page = new GenericSelectionPage(
                "Select Product",
                    new SelectionViewModel<Product>(
                    new Filter<Product>(X=>X.Expired).IsEqualTo(DateTime.MinValue),
                    new Expression<Func<Product, object>>[] { X => X.Code, X => X.Name },
                    new Expression<Func<Product, object>>[] { x=>x.Image.ID, x=>x.Units.ID, x=>x.Units.Code, x=>x.Units.Description, x=>x.DefaultStyle.ID, x=>x.DefaultStyle.Code, x=>x.DefaultStyle.Description },
                    new SortOrder<Product>(x => x.Code)
                )
            );
            page.OnItemSelected += (o,e) => {

                _product = e.Row.ToObject<Product>();

                _style = new ProductStyle()
                {
                    ID = _product.DefaultStyle.ID,
                    Code = _product.DefaultStyle.Code,
                    Description = _product.DefaultStyle.Description
                };

                _uom = new ProductUOM()
                {
                    ID = _product.Units.ID,
                    Code = _product.Units.Code,
                    Description = _product.Units.Description
                };

                _image = new Client<Document>().Load(new Filter<Document>(x => x.ID).IsEqualTo(_product.Image.ID)).FirstOrDefault();
            };
            Navigation.PushAsync(page);
        }

        void SelectStyle_Clicked(System.Object sender, System.EventArgs e)
        {
            GenericSelectionPage page = new GenericSelectionPage(
                "Select Product Style",
                new SelectionViewModel<ProductStyle>(
                    null,
                    new Expression<Func<ProductStyle, object>>[] { x => x.Code, x => x.Description },
                    null,
                    new SortOrder<ProductStyle>(x => x.Code)
                )
            ); 
            page.OnItemSelected += (o,e) => {
                _style = e.Row.ToObject<ProductStyle>();
            };
            Navigation.PushAsync(page);
        }

        void SelectJob_Clicked(System.Object sender, System.EventArgs e)
        {
            JobSelectionPage jobSelectionPage = new JobSelectionPage(
                (job) =>
                {
                    _job.ID = job.ID;
                    _job.Name = job.Name;
                    _job.JobNumber = job.JobNumber;
                }
            );
            Navigation.PushAsync(jobSelectionPage);
        }

        void SelectUnits_Clicked(System.Object sender, System.EventArgs e)
        {
            GenericSelectionPage page = new GenericSelectionPage(
                "Select UOM",
                new SelectionViewModel<ProductUOM>(
                    null,
                    new Expression<Func<ProductUOM, object>>[] { x=>x.Code, x => x.Description },
                    null,
                    new SortOrder<ProductUOM>(x => x.Description)
                )
            );
            page.OnItemSelected += (o,e) => {
                _uom = e.Row.ToObject<ProductUOM>();
            };
            Navigation.PushAsync(page);
        }

        void SmallerSize_Clicked(System.Object sender, System.EventArgs e)
        {
            _unitsize = Math.Max(_unitsize - 1.0F, 0.0F);
            Size.Text = _unitsize.ToString();
        }

        void LargerSize_Clicked(System.Object sender, System.EventArgs e)
        {
            _unitsize += 1.0F;
            Size.Text = _unitsize.ToString();
        }

        void Size_TextChanged(System.Object sender, Xamarin.Forms.TextChangedEventArgs e)
        {
            if (double.TryParse(Size.Text, out double size))
                _unitsize = size;
            
        }
    }
}