using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using Avalonia;
using Avalonia.Animation;
using Avalonia.Controls;
using Avalonia.Controls.Metadata;
using Avalonia.Controls.Primitives;
using Avalonia.Interactivity;
using Avalonia.Media;
using Avalonia.Media.Immutable;
using Avalonia.Styling;
using Avalonia.Threading;
using AvaloniaEdit;
using AvaloniaEdit.Indentation.CSharp;
using FluentAvalonia.Core.Attributes;
using FluentAvalonia.UI.Controls;

namespace FluentAvaloniaSamples.Controls;

public class ControlDefinitionOverlay : TemplatedControl
{
    public ControlDefinitionOverlay()
    {
        IsVisible = false;
    }

    public static readonly StyledProperty<Type> TargetTypeProperty =
        AvaloniaProperty.Register<ControlDefinitionOverlay, Type>(nameof(TargetType));

    public static readonly StyledProperty<string> InheritanceProperty =
        AvaloniaProperty.Register<ControlDefinitionOverlay, string>(nameof(Inheritance));

    public static readonly StyledProperty<string> PseudoclassesListProperty =
        AvaloniaProperty.Register<ControlDefinitionOverlay, string>(nameof(PseudoclassesList));

    public Type TargetType
    {
        get => GetValue(TargetTypeProperty);
        set => SetValue(TargetTypeProperty, value);
    }

    public string Inheritance
    {
        get => GetValue(InheritanceProperty);
        set => SetValue(InheritanceProperty, value);
    }

    public string PseudoclassesList
    {
        get => GetValue(PseudoclassesListProperty);
        set => SetValue(PseudoclassesListProperty, value);
    }


    protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
    {
        if (_closeButton != null)
            _closeButton.Click -= OnCloseClick;

        base.OnApplyTemplate(e);

       // _textEditor = e.NameScope.Find<TextEditor>("TextEditor");

        //_textEditor.TextArea.IndentationStrategy = new CSharpIndentationStrategy();
        //_textEditor.SyntaxHighlighting = CSharpHighlightingSource.CSharpDarkMode;

        _closeButton = e.NameScope.Find<Button>("CloseButton");
        _closeButton.Click += OnCloseClick;

        Show();
    }

    public async void Show()
    {
        Inheritance = null;
        PseudoclassesList = null;

        //if (_textEditor != null)
        //    _textEditor.Text = null;

        Opacity = 0;
        IsVisible = true;
        var ani = new Animation
        {
            Duration = TimeSpan.FromMilliseconds(250),
            Children =
            {
                new KeyFrame
                {
                    Cue = new Cue(0d),
                    Setters =
                    {
                        new Setter(OpacityProperty, 0d),
                        new Setter(ScaleTransform.ScaleXProperty, 1.05d),
                        new Setter(ScaleTransform.ScaleYProperty, 1.05d)
                    }
                },
                new KeyFrame
                {
                    Cue = new Cue(1d),
                    Setters =
                    {
                        new Setter(OpacityProperty, 1d),
                        new Setter(ScaleTransform.ScaleXProperty, 1d),
                        new Setter(ScaleTransform.ScaleYProperty, 1d)
                    },
                    KeySpline = new KeySpline(0,0,0,1)
                }
            },
            FillMode = FillMode.Forward
        };

        await ani.RunAsync(this);

        await BuildControlDefinition(TargetType);

        if (this.TryFindResource("TextControlSelectionHighlightColor", out var value))
        {
            if (value is ISolidColorBrush sb)
            {
                var b = new ImmutableSolidColorBrush(sb.Color, 0.5);
                //_textEditor.TextArea.SelectionBrush = b;
            }
        }
    }

    public async void Hide()
    {
        var ani = new Animation
        {
            Duration = TimeSpan.FromMilliseconds(167),
            Children =
            {
                new KeyFrame
                {
                    Cue = new Cue(0d),
                    Setters =
                    {
                        new Setter(OpacityProperty, 1d),
                        new Setter(ScaleTransform.ScaleXProperty, 1d),
                        new Setter(ScaleTransform.ScaleYProperty, 1d)
                    }
                },
                new KeyFrame
                {
                    Cue = new Cue(1d),
                    Setters =
                    {
                        new Setter(OpacityProperty, 0d),
                        new Setter(ScaleTransform.ScaleXProperty, 1.05d),
                        new Setter(ScaleTransform.ScaleYProperty, 1.05d)
                    },
                    KeySpline = new KeySpline(0,0,0,1)
                }
            },
            FillMode = FillMode.Forward
        };

        await ani.RunAsync(this);

        IsVisible = false;
    }

    public async Task<bool> BuildControlDefinition(Type t)
    {
        return await Task.Run(() =>
        {
            try
            {
                var inheritance = GetInheritance(t);

                var ps = GetPseudoclasses(t);

                var src = GeneratePseudoSource(t);

                Dispatcher.UIThread.Post(() =>
                {
                    Inheritance = inheritance;
                    PseudoclassesList = ps;
                    //_textEditor.Text = src;

                    //_textEditor.TextArea.IndentationStrategy.IndentLines(_textEditor.Document, 0, _textEditor.Document.LineCount);

                }, DispatcherPriority.Background);

                return true;
            }
            catch
            {
                return false;
            }
        });
    }

    private string GetInheritance(Type t)
    {
        var sb = new StringBuilder();

        sb.Append(t.Name);

        var cur = t.BaseType;
        while (cur != null)
        {
            sb.Insert(0, " > ");
            sb.Insert(0, cur.Name);
            cur = cur.BaseType;
        }

        return sb.ToString();
    }

    private string GetPseudoclasses(Type t)
    {
        var pcAttr = t.GetCustomAttributes(typeof(PseudoClassesAttribute), true);
        var sb = new StringBuilder();
        foreach (PseudoClassesAttribute attr in pcAttr)
        {
            foreach (var pc in attr.PseudoClasses)
            {
                sb.Append(pc);
                sb.Append(',');
            }
        }

        sb.Remove(sb.Length - 1, 1);
        return sb.ToString();
    }

    private string GeneratePseudoSource(Type t)
    {
        var sb = new StringBuilder();

        // Generate class name
        sb.Append($"public class {t.Name} : {t.BaseType.Name}");

        sb.Append("\n{\n");

        // Ignore constructors, all controls have to have a public ctor 

        // AvaloniaProperties
        sb.AppendLine("// Avalonia Properties");

        var avProps = AvaloniaPropertyRegistry.Instance.GetRegistered(t)
            .Where(x => x.OwnerType == t);

        foreach (var p in avProps)
        {
            if (p.IsDirect)
            {
                sb.AppendLine($"public static readonly DirectProperty<{p.OwnerType.Name}, {ResolveType(p.PropertyType)}> {p.Name}Property;");
            }
            else
            {
                sb.AppendLine($"public static readonly StyledProperty<{ResolveType(p.PropertyType)}> {p.Name}Property;");
            }
        }

        sb.Append("\n");

        // CLR properties
        sb.AppendLine("// CLR Properties");

        var clr = t.GetProperties(BindingFlags.Instance | BindingFlags.Public)
            .Where(x => x.DeclaringType == t);

        // Keep track of enums used, we'll define them too at the end of the file
        List<Type> enums = new List<Type>();

        foreach (var p in clr)
        {
            if (p.GetCustomAttribute<NotImplementedAttribute>(true) != null)
            {
                sb.Append("[Not Implemented] ");
            }

            sb.Append($"public {ResolveType(p.PropertyType)} {p.Name}");

            // I don't know of many set only properties so we're safe with this
            sb.Append(" { get; ");

            if (p.CanWrite)
            {
                sb.Append("set; }\n");
            }
            else
            {
                sb.Append("}\n");
            }

            if (p.PropertyType.IsEnum)
            {
                enums.Add(p.PropertyType);
            }
        }

        sb.Append("\n");

        // Public events
        sb.AppendLine("// Events");

        var events = t.GetEvents(BindingFlags.Instance | BindingFlags.Public)
            .Where(x => x.DeclaringType == t);

        foreach (var ev in events)
        {
            if (ev.GetCustomAttribute<NotImplementedAttribute>(true) != null)
            {
                sb.Append("[Not Implemented] ");
            }

            sb.Append("public event ");

            sb.Append(ResolveType(ev.EventHandlerType));
            sb.Append(' ');
            sb.Append(ev.Name);
            sb.Append(';');
            sb.Append('\n');
        }

        sb.Append("\n");

        // Public methods

        sb.AppendLine("// Public Methods");

        var methods = t.GetMethods(BindingFlags.Instance | BindingFlags.Public)
            .Where(x => x.DeclaringType == t && !x.IsSpecialName && x.GetBaseDefinition() == x);

        foreach (var m in methods)
        {
            if (m.GetCustomAttribute<NotImplementedAttribute>(true) != null)
            {
                sb.Append("[Not Implemented] ");
            }

            sb.Append("public ");

            if (m.IsVirtual)
            {
                sb.Append("virtual ");
            }

            sb.Append(ResolveType(m.ReturnType));
            sb.Append(' ');

            sb.Append(m.Name);
            sb.Append('(');

            var args = m.GetParameters();
            foreach (var arg in args)
            {
                sb.Append(ResolveType(arg.ParameterType));
                sb.Append(' ');
                sb.Append(arg.Name);
                sb.Append(", ");
            }

            if (args.Length > 0)
            {
                sb.Remove(sb.Length - 2, 2);
            }
            sb.Append(')');
            sb.Append(';');
            sb.Append('\n');
        }


        sb.AppendLine("}\n");

        // Now any enums used in the above class, let's define here

        foreach (var en in enums)
        {
            // Skip the Symbol enum because it's too big and can be looked up on the SymbolIcon page
            if (en == typeof(Symbol))
                continue;

            if (en.GetCustomAttribute<FlagsAttribute>() != null)
            {
                sb.Append("[Flags]\n");
            }

            sb.Append("public enum ");
            sb.Append(en.Name);
            sb.Append("\n{\n");

            var names = Enum.GetNames(en);
            for (int i = 0; i < names.Length; i++)
            {
                var fi = en.GetField(names[i]);

                if (fi.GetCustomAttribute<ObsoleteAttribute>() != null)
                {
                    sb.Append("[Obsolete] ");
                }

                sb.Append(names[i]);
                sb.Append(' ');
                sb.Append('=');
                sb.Append(' ');
                sb.Append(fi.GetRawConstantValue().ToString());
                sb.Append(',');
                sb.Append('\n');
            }

            sb.AppendLine("}\n");
        }

        return sb.ToString();
    }

    private string ResolveType(Type t)
    {
        if (t.IsGenericType)
        {
            var genType = t.GetGenericTypeDefinition().Name;
            genType = genType.Substring(0, genType.IndexOf('`'));
            var args = t.GetGenericArguments().Select(x => ResolveType(x)).ToArray();

            if (genType.Equals("Nullable", StringComparison.OrdinalIgnoreCase))
            {
                return $"{args[0]}?";
            }
            else
            {
                return $"{genType}<{string.Join(',', args)}>";
            }
        }
        else
        {
            if (t == typeof(object))
                return "object";
            else if (t == typeof(string))
                return "string";
            else if (t == typeof(bool))
                return "bool";
            else if (t == typeof(char))
                return "char";
            else if (t == typeof(int))
                return "int";
            else if (t == typeof(float))
                return "float";
            else if (t == typeof(double))
                return "double";
            else if (t == typeof(long))
                return "long";
            else if (t == typeof(ulong))
                return "ulong";
            else if (t == typeof(uint))
                return "uint";
            else if (t == typeof(byte))
                return "byte";
            else if (t == typeof(short))
                return "short";
            else if (t == typeof(decimal))
                return "decimal";
            else if (t == typeof(void))
                return "void";

            return t.Name;
        }
    }

    private void OnCloseClick(object sender, RoutedEventArgs e)
    {
        Hide();
    }

    private Button _closeButton;
    //private TextEditor _textEditor;
}