using System;
using System.Data;
using System.Globalization;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using Chernobyl.App.Core;
using Chernobyl.Extensions;
using Chernobyl.Generation;
using Chernobyl.Mathematics;
using LiveCharts;
using LiveCharts.Wpf;

namespace Chernobyl.App.Patterns
{
    // TODO: look into using a graph to display pattern structure:
    // https://stackoverflow.com/questions/16479768/how-to-easily-draw-graphs-in-wpf
    // Looks Good:
    // http://graphviz4net.codeplex.com/ (https://github.com/tomap/Graphviz4Net)

    /// <summary>
    /// Represents the view of an <see cref="IPattern"/>.
    /// </summary>
    public class PatternViewModel : ViewModel
    {
        /// <param name="pattern">The <see cref="IPattern"/> to be displayed.</param>
        public PatternViewModel(IPattern pattern)
        {
            Pattern = pattern;
            var patternData = Pattern.Data.ToArray();

            DataSeries = new SeriesCollection
            {
                new LineSeries
                {
                    Title = "Pattern",
                    Values = new ChartValues<double>(patternData)
                }
            };

            var grandienStops = patternData
                .Select(value => (byte)value.Normalize(Range.Unit, Tuple.Create(0.0, 255.0)))
                .Select((value, index) => new GradientStop(Color.FromRgb(0, 0, value), index / (double)patternData.Length));
            GradientStops = new GradientStopCollection(grandienStops);

            var width = 8;

            // TODO: Create tests to target for features. Each test will test for ever more advanced features.
            // They will fail at first until we fulfill the feature. Use tests as feature plan.
            var rowCreator = Func.StaticFactory(Colors.Black)
                .AddBeat(3, () => Colors.Red)
                .AddRepeater(width);
            var columnCreator = rowCreator.AddRepeater(3);
            var tablePattern = columnCreator();

            Instruments = new DataTable();
            for (int i = 0; i < width; i++)
            {
                Instruments.Columns.Add($"Beat {i}");
            }

            foreach (var row in tablePattern)
            {
                Instruments.Rows.Add(row.Cast<object>().ToArray());
            }
        }

        /// <summary>
        /// The <see cref="IPattern"/> to be displayed.
        /// </summary>
        public IPattern Pattern { get; }

        /// <summary>
        /// The series containing the values from the pattern.
        /// </summary>
        public SeriesCollection DataSeries { get; }

        /// <summary>
        /// The colors and their location in the gradient.
        /// </summary>
        public GradientStopCollection GradientStops { get; }

        /// <summary>
        /// Beat information for each pattern.
        /// </summary>
        public DataTable Instruments { get; }
    }

    /// <summary>
    /// Converts a data cell value to a hex color string.
    /// </summary>
    public class ValueToBrushConverter : IValueConverter
    {
        /// <inheritdoc />
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            try
            {
                var dgc = (DataGridCell)value;
                var row = (DataRowView)dgc.DataContext;
                return row[dgc.Column.DisplayIndex].ToString();
            }
            catch (Exception)
            {
                return DependencyProperty.UnsetValue;
            }
        }

        /// <inheritdoc />
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotSupportedException();
        }
    }
}