Shaker/Avalonia/SukiUI/Controls/Stepper.axaml.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using Avalonia;
using Avalonia.Controls;
using Avalonia.Controls.Primitives;
using Avalonia.Interactivity;
using Avalonia.Layout;
using Avalonia.Markup.Xaml.MarkupExtensions;
using Avalonia.Media;
using Avalonia.Threading;
using SukiUI.Content;

namespace SukiUI.Controls
{
    public class Stepper : TemplatedControl
    {
        public static readonly StyledProperty<bool> AlternativeStyleProperty =
            AvaloniaProperty.Register<Stepper, bool>(nameof(AlternativeStyle));


        public static readonly StyledProperty<int> IndexProperty =
            AvaloniaProperty.Register<Stepper, int>(nameof(Index));

        public static readonly StyledProperty<IEnumerable?> StepsProperty =
            AvaloniaProperty.Register<Stepper, IEnumerable?>(nameof(Steps));

        public bool AlternativeStyle
        {
            get => GetValue(AlternativeStyleProperty);
            set => SetValue(AlternativeStyleProperty, value);
        }

        public int Index
        {
            get => GetValue(IndexProperty);
            set => SetValue(IndexProperty, value);
        }

        public IEnumerable? Steps
        {
            get => GetValue(StepsProperty);
            set => SetValue(StepsProperty, value);
        }

        private Grid? _grid;

        protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
        {
            base.OnApplyTemplate(e);
            if (e.NameScope.Get<Grid>("PART_GridStepper") is not { } grid)
            {
                return;
            }

            _grid = grid;
            StepsChangedHandler(Steps);
        }

        protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
        {
            base.OnPropertyChanged(change);
            if (change.Property == IndexProperty || change.Property == StepsProperty) 
                StepsChangedHandler(Steps);
        }

        private void StepsChangedHandler(IEnumerable? newSteps)
        {
            if (newSteps is null)
            {
                return;
            }

            if (newSteps is not IEnumerable<object> stepsEnumerable)
            {
                return;
            }

            var steps = stepsEnumerable.ToArray();

            if (AlternativeStyle)
            {
                UpdateAlternate(steps);
            }
            else
            {
                Update(steps);
            }

            if (newSteps is INotifyCollectionChanged notify)
            {
                notify.CollectionChanged += (_, _) => Update(steps);
            }
        }

        #region StepperBaseStyle

        private void Update(object[] steps)
        {
            if (_grid is null)
            {
                return;
            }

            _grid.Children.Clear();

            SetColumnDefinitions(_grid, steps);

            for (var i = 0; i < steps.Length; i++)
            {
                AddStep(steps[i], i, _grid, steps.Length);
            }
        }

        private void SetColumnDefinitions(Grid grid, object[] steps)
        {
            var columns = new ColumnDefinitions();
            for (var i = 0; i < steps.Length; i++)
            {
                columns.Add(new ColumnDefinition());
            }

            grid.ColumnDefinitions = columns;
        }

        private void AddStep(object step, int index, Grid grid, int stepCount)
        {
            var griditem = new Grid
            {
                ColumnDefinitions = new ColumnDefinitions
                    { new(GridLength.Auto), new(GridLength.Star), new(GridLength.Auto) }
            };

            var icon = new PathIcon
                { Height = 10, Width = 10, Data = Icons.ChevronRight, Margin = new Thickness(0, 0, 20, 0), Classes = { "Flippable" } };
            if (index == stepCount - 1)
            {
                icon.IsVisible = false;
            }

            Grid.SetColumn(icon, 2);
            griditem.Children.Add(icon);

            var circle = new Border
            {
                Margin = new Thickness(0, 0, 0, 2),
                Height = 24,
                Width = 24,
                CornerRadius = new CornerRadius(25),
                HorizontalAlignment = HorizontalAlignment.Center,
                VerticalAlignment = VerticalAlignment.Center
            };

            if (index <= Index)
            {
                circle[!BackgroundProperty] = new DynamicResourceExtension("SukiPrimaryColor");

                circle.BorderThickness = new Thickness(0);
                circle.Child = new TextBlock
                {
                    VerticalAlignment = VerticalAlignment.Center,
                    HorizontalAlignment = HorizontalAlignment.Center,
                    Text = (index + 1).ToString(),
                    FontSize = 13,
                    Foreground = Brushes.White, TextWrapping = TextWrapping.Wrap
                };
            }
            else
            {
                circle[!BackgroundProperty] = new DynamicResourceExtension("SukiControlBorderBrush");

                circle.BorderThickness = new Thickness(0);
                circle.Child = new TextBlock
                {
                    VerticalAlignment = VerticalAlignment.Center,
                    HorizontalAlignment = HorizontalAlignment.Center,
                    Text = (index + 1).ToString(),
                    FontSize = 13,
                    Foreground = Brushes.White, TextWrapping = TextWrapping.Wrap
                };
            }

            Grid.SetColumn(circle, 0);
            griditem.Children.Add(circle);
            Control content = step switch
            {
                string s => new TextBlock
                {
                    FontWeight = index <= Index
                        ? TryGetResource("DefaultDemiBold", ActualThemeVariant, out var fontWeight)
                            ? (FontWeight)fontWeight!
                            : FontWeight.Bold
                        : FontWeight.Normal,
                    Margin = new Thickness(10, 0, 0, 0),
                    Text = s,
                    VerticalAlignment = VerticalAlignment.Center,
                    HorizontalAlignment = HorizontalAlignment.Left, TextWrapping = TextWrapping.Wrap
                },
                _ => new ContentControl { Content = step }
            };

            Grid.SetColumn(content, 1);
            griditem.Children.Add(content);

            Grid.SetColumn(griditem, index);

            grid.Children.Add(griditem);
        }

        #endregion

        #region StepperAlternateStyle

        public void UpdateAlternate(object[] steps)
        {
            if (_grid is null)
            {
                return;
            }

            _grid.Children.Clear();

            SetColumnDefinitionsAlternate(_grid);

            for (var i = 0; i < steps.Length; i++)
            {
                AddStepAlternate(steps[i], i, _grid, steps);
            }
        }

        private void SetColumnDefinitionsAlternate(Grid grid)
        {
            var columns = new ColumnDefinitions();
            foreach (var s in Steps)
            {
                columns.Add(new ColumnDefinition());
            }

            grid.ColumnDefinitions = columns;
        }

        private void AddStepAlternate(object step, int index, Grid grid, object[] steps)
        {
            var gridItem = new Grid { ColumnDefinitions = new ColumnDefinitions { new(), new() } };

            var line = new Border
            {
                CornerRadius = new CornerRadius(3), Margin = new Thickness(-5, 0, 23, 0),
                Height = 2,
                HorizontalAlignment = HorizontalAlignment.Stretch,
                VerticalAlignment = VerticalAlignment.Center,
                [!BackgroundProperty] = new DynamicResourceExtension("SukiControlBorderBrush")
            };
            var line1 = new Border
            {
                CornerRadius = new CornerRadius(3), Margin = new Thickness(23, 0, -5, 0),
                Height = 2, HorizontalAlignment = HorizontalAlignment.Stretch,
                VerticalAlignment = VerticalAlignment.Center,
                [!BackgroundProperty] = new DynamicResourceExtension("SukiControlBorderBrush")
            };

            if (index == 0)
            {
                line.IsVisible = false;
            }

            if (index == steps.Length - 1)
            {
                line1.IsVisible = false;
            }

            if (index == Index)
            {
                line[!BackgroundProperty] = new DynamicResourceExtension("SukiPrimaryColor");
            }

            if (index < Index)
            {
                line1[!BackgroundProperty] = new DynamicResourceExtension("SukiPrimaryColor");
                line[!BackgroundProperty] = new DynamicResourceExtension("SukiPrimaryColor");
            }

            Grid.SetColumn(line, 0);
            Grid.SetColumn(line1, 1);

            gridItem.Children.Add(line);
            gridItem.Children.Add(line1);

            var gridBorder = new Grid();

            var circle = new Border
            {
                Margin = new Thickness(0, 0, 0, 2),
                Height = 30,
                Width = 30,
                CornerRadius = new CornerRadius(25),
                HorizontalAlignment = HorizontalAlignment.Center,
                VerticalAlignment = VerticalAlignment.Center
            };

            if (index == Index)
            {
                circle[!BackgroundProperty] = new DynamicResourceExtension("SukiPrimaryColor");
                circle.BorderThickness = new Thickness(0);
                circle.Child = new TextBlock
                {
                    VerticalAlignment = VerticalAlignment.Center,
                    HorizontalAlignment = HorizontalAlignment.Center,
                    Text = (index + 1).ToString(),
                    Foreground = Brushes.White
                };
            }
            else if (index < Index)
            {
                circle.Background = Brushes.Transparent;
                circle.BorderThickness = new Thickness(1.5);
                circle[!BorderBrushProperty] = new DynamicResourceExtension("SukiPrimaryColor");
                circle.Child = new TextBlock
                {
                    VerticalAlignment = VerticalAlignment.Center,
                    HorizontalAlignment = HorizontalAlignment.Center,
                    Text = (index + 1).ToString(),
                    [!ForegroundProperty] = new DynamicResourceExtension("SukiPrimaryColor")
                };
            }
            else
            {
                circle.Background = Brushes.Transparent;
                circle.BorderThickness = new Thickness(1.5);
                circle[!BorderBrushProperty] = new DynamicResourceExtension("SukiControlBorderBrush");
                circle.Child = new TextBlock
                {
                    VerticalAlignment = VerticalAlignment.Center,
                    HorizontalAlignment = HorizontalAlignment.Center,
                    Text = (index + 1).ToString(),
                    [!ForegroundProperty] = new DynamicResourceExtension("SukiControlBorderBrush")
                };
            }

            gridBorder.Children.Add(circle);

            gridBorder.Children.Add(new TextBlock
            {
                FontWeight = index == Index ? FontWeight.Medium : FontWeight.Normal,
                Text = step.ToString(), VerticalAlignment = VerticalAlignment.Center,
                HorizontalAlignment = HorizontalAlignment.Center, Margin = new Thickness(0, 55, 0, 0)
            });

            Grid.SetColumn(gridItem, index);
            Grid.SetColumn(gridBorder, index);
            grid.Children.Add(gridItem);
            grid.Children.Add(gridBorder);
        }

        #endregion
    }
}