using Billing.Models;
using Billing.Themes;
using Billing.UI;
using Microcharts;
using SkiaSharp;
using SkiaSharp.Views.Forms;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Xamarin.Essentials;
using Xamarin.Forms;
using Resource = Billing.Languages.Resource;

namespace Billing.Views
{
    public partial class RankPage : BillingPage
    {
        private static readonly BindableProperty ChartProperty = Helper.Create<Chart, RankPage>(nameof(Chart));
        private static readonly BindableProperty CategoryChartProperty = Helper.Create<Chart, RankPage>(nameof(CategoryChart));
        private static readonly BindableProperty TopBillsProperty = Helper.Create<IList<UIBill>, RankPage>(nameof(TopBills));
        private static readonly BindableProperty NoResultChartProperty = Helper.Create<bool, RankPage>(nameof(NoResultChart));
        private static readonly BindableProperty NoResultCategoryChartProperty = Helper.Create<bool, RankPage>(nameof(NoResultCategoryChart));
        private static readonly BindableProperty NoResultTopBillsProperty = Helper.Create<bool, RankPage>(nameof(NoResultTopBills));

        public Chart Chart
        {
            get => (Chart)GetValue(ChartProperty);
            set => SetValue(ChartProperty, value);
        }
        public Chart CategoryChart
        {
            get => (Chart)GetValue(CategoryChartProperty);
            set => SetValue(CategoryChartProperty, value);
        }
        public IList<UIBill> TopBills
        {
            get => (IList<UIBill>)GetValue(TopBillsProperty);
            set => SetValue(TopBillsProperty, value);
        }
        public bool NoResultChart
        {
            get => (bool)GetValue(NoResultChartProperty);
            set => SetValue(NoResultChartProperty, value);
        }
        public bool NoResultCategoryChart
        {
            get => (bool)GetValue(NoResultCategoryChartProperty);
            set => SetValue(NoResultCategoryChartProperty, value);
        }
        public bool NoResultTopBills
        {
            get => (bool)GetValue(NoResultTopBillsProperty);
            set => SetValue(NoResultTopBillsProperty, value);
        }

        public Command LeftCommand { get; }
        public Command RightCommand { get; }
        public Command FilterCommand { get; }
        public Command EditBilling { get; }

        private DateTime current;
        private DateTime end;
        private IEnumerable<Bill> bills;
        private CategoryType type = CategoryType.Spending;

        private readonly SKTypeface font;

        public RankPage()
        {
            LeftCommand = new Command(OnLeftCommand);
            RightCommand = new Command(OnRightCommand);
            EditBilling = new Command(OnEditBilling);

            var style = SKFontManager.Default.GetFontStyles("PingFang SC");
            if (style != null)
            {
                font = style.CreateTypeface(SKFontStyle.Normal);
            }

            InitializeComponent();
        }

        public override void OnLoaded()
        {
            SetMonth(DateTime.Today);
        }

        private void OnLeftCommand()
        {
            if (scroller.ScrollY > 0)
            {
                scroller.ScrollToAsync(0, 0, true);
            }
            SetMonth(current.AddMonths(-1));
        }

        private void OnRightCommand()
        {
            if (scroller.ScrollY > 0)
            {
                scroller.ScrollToAsync(0, 0, true);
            }
            SetMonth(current.AddMonths(1));
        }

        private async void OnEditBilling(object o)
        {
            if (Tap.IsBusy)
            {
                return;
            }
            using (Tap.Start())
            {
                if (o is UIBill bill)
                {
                    var page = new AddBillPage(bill.Bill);
                    page.BillChecked += OnBillChecked;
                    await Navigation.PushAsync(page);
                }
            }
        }

        private void UpdateBill(UIBill bill)
        {
            bill.Icon = App.Categories.FirstOrDefault(c => c.Id == bill.Bill.CategoryId)?.Icon ?? BaseModel.ICON_DEFAULT;
            bill.Name = bill.Bill.Name;
            bill.DateCreation = bill.Bill.CreateTime;
            bill.Amount = bill.Bill.Amount;
            bill.Wallet = App.Accounts.FirstOrDefault(a => a.Id == bill.Bill.WalletId)?.Name;
        }

        private void OnBillChecked(object sender, Bill e)
        {
            var bill = TopBills.FirstOrDefault(b => b.Bill == e);
            if (bill != null)
            {
                UpdateBill(bill);
            }

            Task.Run(App.WriteBills);
        }

        private async void SetMonth(DateTime date)
        {
            current = date.AddDays(1 - date.Day);
            end = current.AddDays(DateTime.DaysInMonth(current.Year, current.Month));

            var format = Resource.DateRangeFormat;
            Title = current.ToString(format) + " ~ " + end.AddDays(-1).ToString(format);

            var spending = type == CategoryType.Spending;
            bills = await Task.Run(() => App.Bills.Where(b => (b.Amount > 0 ^ spending) && b.CreateTime >= current && b.CreateTime <= end));

            var primaryColor = BaseTheme.CurrentPrimaryColor.ToSKColor();
            var textColor = BaseTheme.CurrentSecondaryTextColor.ToSKColor();

            _ = Task.Run(() => LoadReportChart(primaryColor, textColor));
            _ = Task.Run(() => LoadCategoryChart(primaryColor, textColor));
            _ = Task.Run(LoadTopBills);
        }

        private void LoadReportChart(SKColor primaryColor, SKColor textColor)
        {
            var entries = new List<ChartEntry>();
            for (var day = current; day <= end; day = day.AddDays(1))
            {
                var daybills = bills.Where(b => Helper.IsSameDay(b.CreateTime, day));
                decimal amount = Math.Abs(daybills.Sum(b => b.Amount));
                if (amount > 0)
                {
                    entries.Add(new((float)amount)
                    {
                        Label = day.ToString("MM-dd"),
                        ValueLabel = amount.ToString("#,##0.##"),
                        Color = primaryColor,
                        TextColor = textColor,
                        ValueLabelColor = textColor
                    });
                }
            }

            MainThread.BeginInvokeOnMainThread(() =>
            {
                if (entries.Count > 0)
                {
                    NoResultChart = false;
                    Chart = new LineChart
                    {
                        BackgroundColor = SKColors.Transparent,
                        LabelTextSize = 24,
                        Entries = entries
                    };
                }
                else
                {
                    Chart = null;
                    NoResultChart = true;
                }
            });
        }

        private void LoadCategoryChart(SKColor primaryColor, SKColor textColor)
        {
            var entries = new List<ChartEntry>();
            var groups = bills.GroupBy(b => b.CategoryId);
            var dict = new Dictionary<string, decimal>();
            decimal all = 0m;
            foreach (var g in groups)
            {
                var categoryId = g.Key;
                var category = App.Categories.FirstOrDefault(c => c.Id == categoryId);
                if (category?.ParentId != null)
                {
                    category = App.Categories.FirstOrDefault(c => c.Id == category.ParentId) ?? category;
                }
                if (category != null)
                {
                    var total = Math.Abs(g.Sum(g => g.Amount));
                    all += total;
                    if (dict.ContainsKey(category.Name))
                    {
                        dict[category.Name] += total;
                    }
                    else
                    {
                        dict.Add(category.Name, total);
                    }
                }
            }
            foreach (var kv in dict)
            {
                entries.Add(new((float)kv.Value)
                {
                    Label = kv.Key,
                    ValueLabel = (kv.Value * 100 / all).ToString("0.#") + "%",
                    Color = primaryColor,
                    TextColor = textColor,
                    ValueLabelColor = textColor
                });
            }

            MainThread.BeginInvokeOnMainThread(() =>
            {
                if (entries.Count > 0)
                {
                    NoResultCategoryChart = false;
                    CategoryChart = new RadarChart
                    {
                        BackgroundColor = SKColors.Transparent,
                        LabelTextSize = 30,
                        Typeface = font,
                        Entries = entries
                    };
                }
                else
                {
                    CategoryChart = null;
                    NoResultCategoryChart = true;
                }
            });
        }

        private void LoadTopBills()
        {
            List<UIBill> topBills = bills.OrderByDescending(b => Math.Abs(b.Amount)).Take(10).Select(b => Helper.WrapBill(b)).ToList();

            MainThread.BeginInvokeOnMainThread(() =>
            {
                if (topBills.Count > 0)
                {
                    NoResultTopBills = false;
                    TopBills = topBills;
                }
                else
                {
                    TopBills = null;
                    NoResultTopBills = true;
                }
            });
        }
    }
}