using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Essentials;
using Xamarin.Forms;
using ZXing;
using ZXing;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
using comal.timesheets.CustomControls;
using Comal.Classes;
using InABox.Core;
using InABox.Clients;
using System.Threading;
using static comal.timesheets.RequiItems;

namespace comal.timesheets.StoreRequis
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class StoreRequisMainPage : ContentPage
    {

        public delegate bool OnScanEvent(object sender, String barcode);

        public event OnScanEvent OnScan;

        Dictionary<StoreRequiItem, string> itemRowScannerRawResultPairs;

        Dictionary<StoreRequiItem, string> itemRowScannerProcessedResultPairs;

        Dictionary<int, StoreRequiItem> idItemRowPairs;

        bool choosingLocation;

        Requisition requisition;

        bool newRequisition;

        int count;

        int itemsCount;

        #region Constructor, appearing and disappearing

        public StoreRequisMainPage(Guid _requiID)
        {
            InitializeComponent();
            var options = new ZXing.Mobile.MobileBarcodeScanningOptions()
            {
                PossibleFormats = new List<ZXing.BarcodeFormat>() { ZXing.BarcodeFormat.QR_CODE },
                AutoRotate = false,
                TryInverted = true,
                TryHarder = true,
            };
            _scanView.Options = options;
            _scanView.IsAnalyzing = false;
            _scanView.IsScanning = true;
            _scanView.OnScanResult += ScanView_OnScanResult;
            count = 0;
            choosingLocation = false;
            itemRowScannerRawResultPairs = new Dictionary<StoreRequiItem, string>();
            itemRowScannerProcessedResultPairs = new Dictionary<StoreRequiItem, string>();
            idItemRowPairs = new Dictionary<int, StoreRequiItem>();

            RequiItems.NewRequisitionRows = new List<StoreRequiItem>();
            RequiItems.OldRequisitionItems = new List<RequisitionItem>();

            if (_requiID != Guid.Empty)
            {
                Title = "Loading";
                requisition = new Requisition();
                requisition.ID = _requiID;
                LoadExistingRequi();
            }
            else
            {
                Title = "Scan Items";
                newRequisition = true;
                requisition = new Requisition();
            }
        }
        private async void LoadExistingRequi()
        {
            await Task.Run(() =>
            {
                requisition = new Client<Requisition>().Query(
                    new Filter<Requisition>(x => x.ID).IsEqualTo(requisition.ID)
                    ).Rows.FirstOrDefault().ToObject<Requisition>();
                if (!string.IsNullOrWhiteSpace(requisition.Request))
                {
                    Label notesLbl = new Label()
                    {
                        Text = requisition.Request,
                        Margin = 0,
                        Padding = 0
                    };
                    
                    
                    Device.BeginInvokeOnMainThread(() =>
                    {
                        requestFrame.Content = notesLbl;
                        requestFrame.IsVisible = true;
                    });
                }

                if (RequiItems.OldRequisitionItems.Count > 0)
                    RequiItems.OldRequisitionItems.Clear();
                CoreTable table = new Client<RequisitionItem>().Query
                    (
                    new Filter<RequisitionItem>(x => x.RequisitionLink.ID).IsEqualTo(requisition.ID)
                    );
                if (table.Rows.Any())
                {
                    foreach (CoreRow row in table.Rows)
                    {
                        RequisitionItem requisitionItem = row.ToObject<RequisitionItem>();
                        LoadProduct(new Tuple<string, double>(requisitionItem.Product.Code, requisitionItem.Quantity), requisitionItem.Product.Code, requisitionItem);
                        RequiItems.OldRequisitionItems.Add(requisitionItem);
                    }
                }
                Device.BeginInvokeOnMainThread(() =>
                {
                    Title = "Scan Items";
                });

            });
        }

        protected override void OnAppearing()
        {
            base.OnAppearing();
            _scanView.IsAnalyzing = true;
        }

        protected override void OnDisappearing()
        {
            _scanView.IsAnalyzing = false;
            base.OnDisappearing();
        }

        #endregion

        #region Scan Complete and process results
        private void ScanView_OnScanResult(ZXing.Result result)
        {
            Device.BeginInvokeOnMainThread(() =>
            {
                if (!choosingLocation)
                {
                    if (RequiItems.HoldingsLoaded)
                    {
                        bool bOK = true;
                        if (OnScan != null)
                            bOK = OnScan(this, result.Text);
                        if (bOK)
                        {
                            if (!itemRowScannerRawResultPairs.Values.Contains(result.Text))
                            {
                                if (!itemRowScannerProcessedResultPairs.Values.Contains(result.Text))
                                {
                                    Vibration.Vibrate();
                                    string rawResult = result.Text;
                                    Tuple<string, double> tuple = ProcessResult(result.Text);
                                    LoadProduct(tuple, rawResult, new RequisitionItem());
                                }
                            }
                        }
                    }
                }
            });
        }

        private Tuple<string, double> ProcessResult(string result)
        {
            double qty = 1;
            if (result.Contains("*"))
            {
                try
                {
                    int i = result.IndexOf("*");
                    string remainder = result.Substring(i);
                    result = result.Remove(i);                    
                    string s1 = remainder.Substring(1);
                    qty = Convert.ToDouble(s1);
                }
                catch { }
            }
            Tuple<string, double> tuple = new Tuple<string, double>(result, qty);
            return tuple;
        }

        private void LoadProduct(Tuple<string, double> processedResultQtyTuple, string rawResult, RequisitionItem requisitionItem)
        {
            Device.BeginInvokeOnMainThread(async () =>
            {
                //lookup product in productshells cache
                ProductShell product = GlobalVariables.ProductShells.Find(x => x.Code.Equals(processedResultQtyTuple.Item1));

                //lookup holding for product in holdings cache
                //List<HoldingsCacheShell> list = new List<HoldingsCacheShell>();
                string itemLocation = "";
                Guid holdingID = Guid.Empty;

                if (requisitionItem.ID == Guid.Empty)
                {
                    try
                    {
                        List<HoldingsCacheShell> list = holdingsCache.Where(x => x.ProductID.Equals(product.ID)).ToList();
                        if (list.Count == 1) //one stockholding - auto choose shelf
                        {
                            HoldingsCacheShell holding = list.First();
                            itemLocation = holding.LocationName;
                            holdingID = holding.ID;
                        }
                        else if (list.Count > 1)  //more than one stockholding - choose shelf
                        {
                            choosingLocation = true;
                            Dictionary<string, Guid> holdingIDLocations = new Dictionary<string, Guid>();
                            foreach (HoldingsCacheShell holding in list)
                            {
                                if (!holdingIDLocations.ContainsKey(holding.LocationName + " (Qty: " + holding.Units + ")"))
                                {
                                    holdingIDLocations.Add(holding.LocationName + " (Qty: " + holding.Units + ")", holding.ID);
                                }
                            }
                            string[] array = holdingIDLocations.Keys.ToArray();
                            string chosenOption = await DisplayActionSheet("Choose Location", "Cancel", null, array);
                            if (chosenOption != null && chosenOption != "Cancel")
                            {
                                itemLocation = chosenOption;
                                holdingID = holdingIDLocations[chosenOption];
                            }
                            else
                                return;
                        }
                        else if (list.Count == 0)
                        {
                            DisplayAlert("No Holdings Found for Product", "", "OK");
                            return;
                        }
                    }
                    catch(Exception e)
                    {
                        DisplayAlert("Error", e.Message, "OK");
                        return;
                    }
                }
                else
                {
                    itemLocation = requisitionItem.Location.Description;
                    holdingID = requisitionItem.Location.ID;
                }

                StoreRequiItem storeRequiItem = new StoreRequiItem(product, processedResultQtyTuple.Item2, itemLocation, holdingID) //default qty is 1
                {
                    ID = count,
                };
                storeRequiItem.RequiItemID = requisitionItem.ID;
                storeRequiItem.OnZeroSelected += StoreRequiItem_OnZeroSelected;
                storeRequiItem.OnParseError += OnParseError;

                idItemRowPairs.Add(count, storeRequiItem);
                itemRowScannerRawResultPairs.Add(storeRequiItem, rawResult);
                itemRowScannerProcessedResultPairs.Add(storeRequiItem, processedResultQtyTuple.Item1);
                itemRowsFlexlayout.Children.Add(storeRequiItem);
                count++;
                itemsCount++;
                Title = "Store Requis (" + itemsCount + ")";
                choosingLocation = false;
                itemsScroller.ScrollToAsync(storeRequiItem, ScrollToPosition.Center, true);
            });
        }
        #endregion

        #region Buttons Pressed
        private void Add_Clicked(object sender, EventArgs e)
        {
            if (GlobalVariables.ProductsLoaded)
            {
                ProductList products = new ProductList(GlobalVariables.ProductShells, true);
                products.OnProductSelected += ()=> 
                {
                    Tuple<string, double> tuple = new Tuple<string, double>(products.SelectedProduct.Code, 1);

                    LoadProduct(new Tuple<string, double>(products.SelectedProduct.Code, 1), products.SelectedProduct.Code, new RequisitionItem());
                };
                Navigation.PushAsync(products);
            }
        }

        private void NextBtn_Clicked(object sender, EventArgs e)
        {
            if (RequiItems.NewRequisitionRows.Count > 0)
                RequiItems.NewRequisitionRows.Clear();

            if (idItemRowPairs.Count > 0)
            {
                //RequiItems.NewRequisitionRows = idItemRowPairs.Values.ToList();
                //StoreRequiConfirmationPage storeRequiConfirmationPage = new StoreRequiConfirmationPage(requisition);
                //storeRequiConfirmationPage.OnSaveSelected += () => { Navigation.PopAsync(); };
                //Navigation.PushAsync(storeRequiConfirmationPage);
            }
            else
            {
                DisplayAlert("Alert", "Please add items", "Cancel");
            }
        }
        private async void StoreRequiItem_OnZeroSelected(int ID)
        {
            string chosenOption = await DisplayActionSheet("Remove Item?", "Cancel", null, "Yes", "No");
            switch (chosenOption)
            {
                case "Cancel":
                    return;
                    break;
                case "No":
                    return;
                    break;
                case "Yes":
                    break;
                default:
                    return;
                    break;
            }
            StoreRequiItem storeRequiItem = idItemRowPairs[ID];
            itemRowsFlexlayout.Children.Remove(storeRequiItem);
            idItemRowPairs.Remove(ID);
            itemRowScannerRawResultPairs.Remove(storeRequiItem);
            itemRowScannerProcessedResultPairs.Remove(storeRequiItem);
            itemsCount--;
            Title = "Store Requis (" + itemsCount + ")";
        }

        private async void OnParseError()
        {
            DisplayAlert("Error", "Enter only numbers", "OK");
        }

        #endregion



    }
}