using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using TMPro;
using UnityEngine;
using UnityEngine.InputSystem;
using UnityEngine.UI;

public class TestRebindScript : MonoBehaviour
{
    [Header("UI")] public UXButton btn;
    public TextMeshProUGUI bindKeyText;
    public Image targetImage;

    [Tooltip("如果不使用 actionReference，则用 name 在全局 manager 查找")]
    public string actionName = "movement";

    [Header("Optional composite part (WASD style)")] [Tooltip("如果需要绑定 composite 的某一部分（例如 Up/Down/Left/Right），填这个；留空表示绑定非 composite 或整体 binding")]
    public string compositePartName = "";

    [Header("Behavior")] [Tooltip("如果 true，在 Prepare 后自动调用 ConfirmApply() 并保存；否则等待手动 ConfirmPrepared()/CancelPrepared()")]
    public bool autoConfirm = false;

    /// <summary>
    /// 启动时初始化并订阅事件
    /// </summary>
    private void Start()
    {
        if (btn != null) btn.onClick.AddListener(OnBtnClicked);
        InputDeviceWatcher.OnDeviceContextChanged += OnDeviceContextChanged;
        InputBindingManager.BindingsChanged += OnBindingsChanged;
        UpdateBindingText();

        if (InputBindingManager.Instance != null)
        {
            // 订阅事件
            InputBindingManager.Instance.OnRebindPrepare += OnRebindPrepareHandler;
            InputBindingManager.Instance.OnApply += OnApplyHandler;
            InputBindingManager.Instance.OnRebindEnd += OnRebindEndHandler;
            InputBindingManager.Instance.OnRebindConflict += OnRebindConflictHandler;
        }
    }

    /// <summary>
    /// 禁用时取消订阅事件
    /// </summary>
    private void OnDisable()
    {
        if (btn != null) btn.onClick.RemoveListener(OnBtnClicked);
        InputDeviceWatcher.OnDeviceContextChanged -= OnDeviceContextChanged;
        InputBindingManager.BindingsChanged -= OnBindingsChanged;

        if (InputBindingManager.Instance != null)
        {
            InputBindingManager.Instance.OnRebindPrepare -= OnRebindPrepareHandler;
            InputBindingManager.Instance.OnApply -= OnApplyHandler;
            InputBindingManager.Instance.OnRebindEnd -= OnRebindEndHandler;
            InputBindingManager.Instance.OnRebindConflict -= OnRebindConflictHandler;
        }
    }

    /// <summary>
    /// 重新绑定准备完成的处理器
    /// </summary>
    private void OnRebindPrepareHandler(InputBindingManager.RebindContext ctx)
    {
        if (IsTargetContext(ctx))
        {
            var disp = ctx.overridePath == InputBindingManager.NULL_BINDING ? "<Cleared>" : ctx.overridePath;
            bindKeyText.text = disp;
            if (autoConfirm) _ = ConfirmPreparedAsync();
        }
    }

    /// <summary>
    /// 应用重新绑定的处理器
    /// </summary>
    private void OnApplyHandler(bool success, HashSet<InputBindingManager.RebindContext> appliedContexts)
    {
        if (appliedContexts != null)
        {
            // 仅当任何应用/丢弃的上下文与此实例匹配时才更新
            foreach (var ctx in appliedContexts)
            {
                if (IsTargetContext(ctx))
                {
                    UpdateBindingText();
                    break;
                }
            }
        }
    }

    /// <summary>
    /// 重新绑定结束的处理器
    /// </summary>
    private void OnRebindEndHandler(bool success, InputBindingManager.RebindContext context)
    {
        if (IsTargetContext(context))
        {
            UpdateBindingText();
        }
    }

    /// <summary>
    /// 重新绑定冲突的处理器
    /// </summary>
    private void OnRebindConflictHandler(InputBindingManager.RebindContext prepared, InputBindingManager.RebindContext conflict)
    {
        // 如果准备的或冲突的上下文匹配此实例，则更新
        if (IsTargetContext(prepared) || IsTargetContext(conflict))
        {
            UpdateBindingText();
        }
    }

    /// <summary>
    /// 设备变更的回调
    /// </summary>
    private void OnDeviceContextChanged(InputDeviceWatcher.DeviceContext _)
    {
        UpdateBindingText();
    }

    private void OnBindingsChanged()
    {
        UpdateBindingText();
    }

    /// <summary>
    /// 获取当前的输入操作
    /// </summary>
    private InputAction GetAction()
    {
        return InputBindingManager.Action(actionName);
    }

    /// <summary>
    /// 判断上下文是否为目标上下文
    /// </summary>
    private bool IsTargetContext(InputBindingManager.RebindContext ctx)
    {
        if (ctx == null || ctx.action == null) return false;
        var action = GetAction();
        if (action == null) return false;

        // 必须匹配操作
        if (ctx.action != action) return false;

        // 如果指定了复合部分，需要匹配绑定索引
        if (!string.IsNullOrEmpty(compositePartName))
        {
            // 获取上下文索引处的绑定
            if (ctx.bindingIndex < 0 || ctx.bindingIndex >= action.bindings.Count)
                return false;

            var binding = action.bindings[ctx.bindingIndex];

            // 检查绑定的名称是否与我们的复合部分匹配
            return string.Equals(binding.name, compositePartName, StringComparison.OrdinalIgnoreCase);
        }

        // 如果未指定复合部分，仅匹配操作就足够了
        return true;
    }

    /// <summary>
    /// 按钮点击的回调
    /// </summary>
    private void OnBtnClicked()
    {
        // 使用管理器 API（我们传递部分名称，以便管理器可以在需要时选择适当的绑定）
        InputBindingManager.StartRebind(actionName, string.IsNullOrEmpty(compositePartName) ? null : compositePartName);
    }

    /// <summary>
    /// 确认准备好的重新绑定（公共方法）
    /// </summary>
    public async void ConfirmPrepared()
    {
        bool ok = await ConfirmPreparedAsync();
        if (!ok) Debug.LogError("ConfirmPrepared: apply failed.");
    }

    /// <summary>
    /// 确认准备好的重新绑定（异步）
    /// </summary>
    private async Task<bool> ConfirmPreparedAsync()
    {
        try
        {
            var task = InputBindingManager.ConfirmApply();
            return await task;
        }
        catch (Exception ex)
        {
            Debug.LogError(ex);
            return false;
        }
    }

    /// <summary>
    /// 取消准备好的重新绑定
    /// </summary>
    public void CancelPrepared()
    {
        InputBindingManager.DiscardPrepared();
        // UpdateBindingText 将通过 OnApply 事件自动调用
    }

    /// <summary>
    /// 更新绑定文本和图标显示
    /// </summary>
    private void UpdateBindingText()
    {
        var action = GetAction();
        var deviceCat = InputDeviceWatcher.CurrentCategory;
        if (action == null)
        {
            bindKeyText.text = "<no action>";
            if (targetImage != null) targetImage.sprite = null;
            return;
        }


        bindKeyText.text = GlyphService.GetDisplayNameFromInputAction(action, compositePartName, deviceCat);


        try
        {
            if (GlyphService.TryGetUISpriteForActionPath(action, compositePartName, deviceCat, out Sprite sprite))
            {
                if (targetImage != null) targetImage.sprite = sprite;
            }
            else
            {
                if (targetImage != null) targetImage.sprite = null;
            }
        }
        catch
        {
            if (targetImage != null) targetImage.sprite = null;
        }
    }
}