using System;
using MvvmCross.Forms.Presenters.Attributes;
using MvvmCross.Forms.Views;
using SkiaSharp;
using SkiaSharp.Views.Forms;
using TestProject.Core.ViewModels.Home;
using TestProject.UI.Extensions;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
using BindExtensions = TestProject.UI.Extensions.BindableObjectExtensions;

namespace TestProject.UI.Pages
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    [MvxContentPagePresentation(WrapInNavigationPage = true)]
    public partial class HomePage : MvxContentPage<HomeViewModel>
    {
        private const float Cos35 = 0.82f;
        private const float LowestPointY = 100f;
        private const float LeftmostPointY = -126.7f;
        private const float LeftmostPointX = -191f;
        private const float OnePercentWight = 3.82f;
        private const float Wight = 382f;
        private const int StarsCount = 5;
        private const int MaxFillValue = 100;

        public static readonly BindableProperty FillValueProperty = BindExtensions.Create<int, HomePage>(nameof(FillValue), p => p.IsFillValueChanged);
        private readonly Point[] halfStarCoordinates = new[]
        {
            new Point(0 , -253),
            new Point(46, -126.7f ),
            new Point(191, -126.7f),
            new Point(76, -38.7f),
            new Point(132, 100),
            new Point(0 , 7.3f),
        };

        public HomePage()
        {
            InitializeComponent();
        }

        public int FillValue
        {
            get => this.GetProperty<int>();
            set => this.SetProperty(value);
        }

        protected override void OnAppearing()
        {
            base.OnAppearing();
        }

        private void DrawStar(SKPath starPath, Point[] coordinatesHalfObject, float offsetX = 0)
        {
            starPath.MoveTo((float)coordinatesHalfObject[0].X + offsetX, (float)coordinatesHalfObject[0].Y);

            for (var i = 1; i < coordinatesHalfObject.Length; i++)
            {
                starPath.LineTo((float)coordinatesHalfObject[i].X + offsetX, (float)coordinatesHalfObject[i].Y);
            }

            starPath.MoveTo((float)coordinatesHalfObject[0].X + offsetX, (float)coordinatesHalfObject[0].Y);

            for (var i = 0; i < coordinatesHalfObject.Length; i++)
            {
                starPath.LineTo((float)coordinatesHalfObject[i].X * -1 + offsetX, (float)coordinatesHalfObject[i].Y);
            }
        }

        SKPath FillStars()
        {
            SKPath fillStars = new SKPath();

            var maxStarsCount = Math.Ceiling(FillValue / (double)(100 / StarsCount));

            for (var j = 0; j < maxStarsCount; j++)
            {
                var offsetX = j * Wight;
                var currentLeftmostPositionX = LeftmostPointX + offsetX;
                var starFillValue = MaxFillValue;

                if (j == maxStarsCount - 1)
                {
                    starFillValue = (FillValue - MaxFillValue / StarsCount * j) * StarsCount;
                }

                for (var i = 0; i < starFillValue; i++)
                {
                    var lineToX = i * OnePercentWight + currentLeftmostPositionX;
                    var lineToXDefault = i * OnePercentWight + LeftmostPointX;

                    if (lineToX <= -46 + offsetX || lineToX >= 46 + offsetX)
                    {
                        var x = Math.Abs(LeftmostPointX) - Math.Abs(lineToXDefault);
                        var y = LeftmostPointY + (x * Cos35);
                        fillStars.MoveTo(lineToX, LeftmostPointY);
                        fillStars.LineTo(lineToX, y);
                    }

                    if (lineToX >= -132 + offsetX && lineToX <= 132 + offsetX)
                    {
                        var heightToWeightUpperBound = 2.7f;
                        var heightToWeightBottomBound = 0.7f;

                        var fromYLength = (132 - Math.Abs(lineToXDefault)) * heightToWeightUpperBound;
                        var toYLength = (132 - Math.Abs(lineToXDefault)) * heightToWeightBottomBound;

                        var fromY = Math.Abs(LowestPointY) - fromYLength;
                        var toY = Math.Abs(LowestPointY) - toYLength;

                        fillStars.MoveTo(lineToX, fromY);
                        fillStars.LineTo(lineToX, toY);
                    }
                }
            }

            return fillStars;
        }

        void OnCanvasViewPaintSurface(object sender, SKPaintSurfaceEventArgs args)
        {
            SKPath emptyStars = new SKPath();

            for(var i = 0; i < StarsCount; i++)
            {
                DrawStar(
                    emptyStars,
                    halfStarCoordinates,
                    Math.Abs(LeftmostPointX) * i * 2);
            }

            SKPaint paintFill = new SKPaint
            {
                Style = SKPaintStyle.Fill,
                Color = SKColors.Gray,
                StrokeWidth = 5
            };

            SKImageInfo info = args.Info;
            SKSurface surface = args.Surface;
            SKCanvas canvas = surface.Canvas;

            canvas.Clear();

            emptyStars.GetBounds(out var bounds);

            canvas.Translate(info.Width / 2, info.Height / 2);

            canvas.Scale(0.8f * Math.Min(info.Width / bounds.Width,
                                         info.Height / bounds.Height));

            canvas.Translate(-bounds.MidX, -bounds.MidY);

            canvas.DrawPath(emptyStars, paintFill);

            var fillStarsPath = FillStars();

            SKPaint paintStroke = new SKPaint
            {
                Style = SKPaintStyle.Stroke,
                Color = SKColors.Gold,
                StrokeWidth = 5
            };

            canvas.DrawPath(fillStarsPath, paintStroke);
        }

        private void IsFillValueChanged(int _, int newValue)
        {
            StarsCanvasView.InvalidateSurface();
        }
    }
}