namespace Sunless.Libraries.UI;

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.AspNetCore.Components;
using Sandbox;

// Mount <MenuHost /> once. Describe screens via Menu.New().WithScreen(...).Apply().
// Screens keyed by id; re-applying replaces in place.
public static class Menu
{
	public static string BrandTop { get; private set; }
	public static string BrandBottom { get; private set; }
	public static string Version { get; private set; }
	public static IReadOnlyList<MenuScreen> Screens => _screens;
	public static string ActiveId { get; private set; }
	public static int Revision { get; private set; }

	public static Action OnNavigateSound { get; set; }

	static readonly List<MenuScreen> _screens = new();

	public static MenuBuilder New() => new();

	public static MenuScreen Active
		=> string.IsNullOrEmpty( ActiveId )
			? null
			: _screens.FirstOrDefault( s => s.Id == ActiveId && s.IsVisible );

	public static IEnumerable<MenuScreen> NavScreens
		=> _screens.Where( s => s.IsVisible && s.ShowInNav ).OrderBy( s => s.Order );

	public static void Navigate( string id )
	{
		if ( ActiveId == id ) return;
		ActiveId = id;
		Revision++;
		try { OnNavigateSound?.Invoke(); }
		catch ( Exception e ) { Log.Warning( $"[Menu] navigate sound threw: {e.Message}" ); }
	}

	public static void Clear()
	{
		_screens.Clear();
		ActiveId = null;
		BrandTop = null;
		BrandBottom = null;
		Version = null;
		Revision++;
	}

	internal static void Commit( MenuBuilder b )
	{
		BrandTop = b._brandTop;
		BrandBottom = b._brandBottom;
		Version = b._version;

		foreach ( var entry in b._screens )
		{
			var existing = _screens.FirstOrDefault( s => s.Id == entry.Id );
			if ( existing is not null ) _screens.Remove( existing );
			_screens.Add( entry );
		}

		if ( Active is null )
		{
			ActiveId = NavScreens.FirstOrDefault()?.Id ?? _screens.FirstOrDefault()?.Id;
		}

		Revision++;
	}
}

public enum MenuTone { Default, Primary, Confirm, Danger, Ghost }

public enum MenuLinkStyle
{
	Row,
	Button,
	Text,
}

public sealed class MenuBuilder
{
	internal string _brandTop;
	internal string _brandBottom;
	internal string _version;
	internal readonly List<MenuScreen> _screens = new();

	public MenuBuilder WithBrand( string top, string bottom = null )
	{
		_brandTop = top;
		_brandBottom = bottom;
		return this;
	}

	public MenuBuilder WithVersion( string version ) { _version = version; return this; }

	public MenuScreenBuilder WithScreen( string id, string label, string icon )
		=> new( this, id, label, icon );

	internal void AddScreen( MenuScreen screen ) => _screens.Add( screen );

	public void Apply() => Menu.Commit( this );
}

public sealed class MenuScreen
{
	public string Id { get; init; }
	public string Label { get; init; }
	public string Icon { get; init; }
	public string Subtitle { get; init; }
	public int Order { get; init; }
	public bool ShowInNav { get; init; } = true;
	public IReadOnlyList<MenuWidget> Widgets { get; init; }

	internal Func<bool> VisibleWhen { get; init; }
	public bool IsVisible => VisibleWhen?.Invoke() ?? true;
}