using Godot;
using System.Collections.Generic;
using System.Linq;
using System.Xml;
using Microsoft.Extensions.DependencyInjection;

namespace BITKit;
/// <summary>
/// 基本UX面板接口,定义了基本的UX面板功能
/// </summary>
/// <para>⭐同步打开与关闭</para>
/// <para>⭐异步打开与关闭</para>
/// <para>⭐当前可见状态</para>
/// <para>⭐基本UI导航回调</para>
public interface IUXPanel
{
    /// <summary>
    /// 该面板是否具有动画
    /// </summary>
    bool IsAnimate { get; }
    /// <summary>
    /// 该面板的索引(入口,Key)
    /// </summary>
    string Index { get; }
    /// <summary>
    /// 该面板是否启用指针
    /// </summary>
    bool AllowCursor { get; }
    /// <summary>
    /// 该面板是否启用玩家输入
    /// </summary>
    bool AllowInput { get; }
    void Entry();
    void Exit();
}

/// <summary>
/// 基本UX服务(GUI管理器),主要通过加载叠加面板实现
/// </summary>
/// <para>使用方式:</para>
/// 
/// 
public partial class UXService : Control
{
    private static UXService Singleton;

    /// <summary>
    /// 在构造函数中注入依赖
    /// </summary>
    public UXService()
    {
        BITApp.ServiceCollection.AddSingleton(this);
        Singleton = this;
    }

    /// <summary>
    /// 注册面板,加入注册队列
    /// </summary>
    /// <param name="panel">UX面板</param>
    public static void Register(IUXPanel panel)
    {
        RegistryQueue.Enqueue(panel);
    }

    /// <summary>
    /// 注销面板
    /// </summary>
    /// <param name="panel">UX面板</param>
    public static void UnRegister(IUXPanel panel)
    {
        UnRegistryQueue.Enqueue(panel);
    }

    public static void Open<T>() where T : IUXPanel
    {
    }

    public static void Return()
    {
        if (History.TryPop(out _))
        {
            if(History.TryPop(out var returnPanel))
            {
                Open(returnPanel);
            }
        }
    }

    public static void Open(IUXPanel panel) => EnableQueue.Push(panel);

    public static void Open(Control control)=>Open(control as IUXPanel);
    public static void Open(string name)
    {

    }

    /// <summary>
    /// 内部注册面板队列
    /// </summary>
    private static readonly Queue<IUXPanel> RegistryQueue = new();
    
    /// <summary>
    /// 内部注销面板队列
    /// </summary>
    private static readonly Queue<IUXPanel> UnRegistryQueue = new();

    /// <summary>
    /// 已注册面板字典
    /// </summary>
    private static readonly Dictionary<string, IUXPanel> Panels = new();

    /// <summary>
    /// 等待启用的面板队列
    /// </summary>
    private static readonly Stack<IUXPanel> EnableQueue = new();

    /// <summary>
    /// 已启用面板
    /// </summary>
    private static readonly Stack<IUXPanel> EnabledPanels = new();

    /// <summary>
    /// 历史面板
    /// </summary>
    private static readonly Stack<IUXPanel> History = new();

    /// <summary>
    /// 正在播放过渡动画的面板
    /// </summary>
    private static readonly Stack<IUXPanel> TransitionPanles = new();

    private static InitializationState InitializationState;

    private void _Entry(IUXPanel panel)
    {

    }

    public override void _Process(double delta)
    {
        if (TransitionPanles.Count is not 0) return;
        while (UnRegistryQueue.TryDequeue(out var result))
        {
            Panels.Remove(result.Index);
        }

        while (RegistryQueue.TryDequeue(out var result))
        {
            Panels.Add(result.Index, result);
            if (InitializationState is InitializationState.Initialized)
                result.Exit();
        }


        if (!EnableQueue.TryPop(out var next)) return;
        if (InitializationState is InitializationState.None)
        {
            foreach (var x in Panels)
            {
                x.Value.Exit();
            }
            InitializationState=InitializationState.Initialized;
        }
        while (EnabledPanels.TryPop(out var enabledPanel))
        {
            enabledPanel.Exit();
        }
        next.Entry();
        EnabledPanels.Push(next);
        History.Push(next);
    }
}