@using C1.Chart;
@using C1.Blazor.Chart;
@using C1.Chart.Annotation;
@using C1.Blazor.Chart.Annotation;
@using System.Drawing;
@using System.IO;
@using System.Reflection;

<FlexChart @ref="chart" Class="chart" ChartType="ChartType.Scatter"
           BindingX="GDP" Binding="Happiness,Population" ItemsSource="Data"
           HeaderContent="Happiness vs GDP per capita (Top 50 countries by population) | 2017 | Source: The World Bank">
    <SeriesCollection>
        <Series />
    </SeriesCollection>
    <AxisCollection>
        <Axis Min="600" Max="100000" AxisType="AxisType.X" LogBase="10" Position="Position.Bottom" AxisLine="false" MajorTickMarks="TickMark.None" />
        <Axis Min="2" Max="9" AxisType="AxisType.Y" Position="Position.Left" AxisLine="false" MajorTickMarks="TickMark.None" />
    </AxisCollection>
</FlexChart>

@code {
        FlexChart chart;

        GdpVsHappiness.CountryData[] Data;

protected override void OnInitialized()
    {
        Data = GdpVsHappiness.GetData();
    }

    protected override void OnAfterRender(bool firstRender)
    {
        base.OnAfterRender(firstRender);
        if (firstRender)
            CreateAnnotations();
    }

    void CreateAnnotations()
    {
        var al = new AnnotationLayer(chart);

        var minx = chart.AxisX.Min;
        var maxx = chart.AxisX.Max;
        var medx = GdpVsHappiness.GdpMedian();

        var miny = chart.AxisY.Min;
        var maxy = chart.AxisY.Max;
        var medy = GdpVsHappiness.HappinessMedian();

        CreateQuadrant(al, 0, "Low GDP - Low satisfaction 🙁", "rgba(100,100,100,0.05)", minx, miny, medx - minx, medy - miny);
        CreateQuadrant(al, 2, "Low GDP - High satisfaction 🙂", "rgba(255,0,0,0.05)", minx, medy, medx - minx, maxy - medy);
        CreateQuadrant(al, 1, "High GDP - Low satisfaction 🙁", "rgba(0,0,255,0.05)", medx, miny, maxx - medx, medy - miny);
        CreateQuadrant(al, 3, "High GDP - High satisfaction 🙂", "rgba(0,255,0,0.05)", medx, medy, maxx - medx, maxy - medy);

        var len = Data.Length;
        for (int i = len - 1; i >= 0; i--)
        {
            var item = Data[i];
            var sz = 16;
            var path = string.Format("https://raw.githubusercontent.com/gosquared/flags/master/flags/flags-iso/shiny/{0}/{1}.png", sz, item.Code);
            var img = new C1.Blazor.Chart.Annotation.Image(path, sz, sz);
            img.Attachment = AnnotationAttachment.DataIndex;
            img.PointIndex = i;
            img.TooltipText = item.Country;
            al.Annotations.Add(img);
        }
    }

    void CreateQuadrant(AnnotationLayer al, int i, string s, string clr, double x, double y, double w, double h)
    {
        var el = new C1.Blazor.Chart.Annotation.Polygon();
        el.Attachment = AnnotationAttachment.DataCoordinate;

        el.Points.Add(new PointF((float)x, (float)y));
        el.Points.Add(new PointF((float)(x + w), (float)y));
        el.Points.Add(new PointF((float)(x + w), (float)(y + h)));
        el.Points.Add(new PointF((float)x, (float)(y + h)));

        el.Style = string.Format("background:{0};color:white;", clr);

        al.Annotations.Add(el);

        var text = new Text(s);
        text.Attachment = AnnotationAttachment.DataCoordinate;
        text.Position = AnnotationPosition.Right;

        switch (i)
        {
            case 0:
                text.Location = new PointF((float)(x + 100), (float)y + 0.5f);
                break;
            case 1:
                text.Position = AnnotationPosition.Left;
                text.Location = new PointF((float)(x + w - 10000), (float)y + 0.5f);
                break;
            case 2:
                text.Location = new PointF((float)(x + 100), (float)(y + h - 0.5));
                break;
            case 3:
                text.Position = AnnotationPosition.Left;
                text.Location = new PointF((float)(x + w - 10000), (float)(y + h - 0.5f));
                break;
        }

        al.Annotations.Add(text);
    }

    public class GdpVsHappiness
    {
        public class CountryData
        {
            public string Country { get; set; }
            public string Code { get; set; }
            public double GDP { get; set; }
            public double Happiness { get; set; }
            public double Population { get; set; }
        }

        static CountryData[] _data;

        static CountryData[] ReadData()
        {
            using (var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream("../Data/GdpVsHappiness.json"))
            {
                using (var sr = new StreamReader(stream))
                {
                    return System.Text.Json.JsonSerializer.Deserialize<CountryData[]>(sr.ReadToEnd());
                }
            }
        }

        public static CountryData[] GetData()
        {
            if (_data == null)
            {
                _data = ReadData();
            }

            return _data;
        }

        public static double GdpMedian()
        {
            return Median(GetData().Select(o => o.GDP));
        }

        public static double HappinessMedian()
        {
            return Median(GetData().Select(o => o.Happiness));
        }

        static double Median(IEnumerable<double> source)
        {
            var data = source.OrderBy(n => n).ToArray();
            if (data.Length % 2 == 0)
                return (data[data.Length / 2 - 1] + data[data.Length / 2]) / 2.0;
            return data[data.Length / 2];
        }
    }
}