using System;
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;

    private void Start()
    {
        if (btn != null) btn.onClick.AddListener(OnBtnClicked);
        InputDeviceWatcher.OnDeviceChanged += OnDeviceChanged;
        UpdateBindingText();

        if (InputBindingManager.Instance != null)
        {
            // Subscribe to events
            InputBindingManager.Instance.OnRebindPrepare += OnRebindPrepareHandler;
            InputBindingManager.Instance.OnApply += OnApplyHandler;
            InputBindingManager.Instance.OnRebindEnd += OnRebindEndHandler;
            InputBindingManager.Instance.OnRebindConflict += OnRebindConflictHandler;
        }
    }

    private void OnDisable()
    {
        if (btn != null) btn.onClick.RemoveListener(OnBtnClicked);
        InputDeviceWatcher.OnDeviceChanged -= OnDeviceChanged;

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

    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();
        }
    }

    private void OnApplyHandler(bool success, HashSet<InputBindingManager.RebindContext> appliedContexts)
    {
        if (appliedContexts != null)
        {
            // Only update if any of the applied/discarded contexts match this instance
            foreach (var ctx in appliedContexts)
            {
                if (IsTargetContext(ctx))
                {
                    UpdateBindingText();
                    break;
                }
            }
        }
    }

    private void OnRebindEndHandler(bool success, InputBindingManager.RebindContext context)
    {
        if (IsTargetContext(context))
        {
            UpdateBindingText();
        }
    }

    private void OnRebindConflictHandler(InputBindingManager.RebindContext prepared, InputBindingManager.RebindContext conflict)
    {
        // Update if either the prepared or conflict context matches this instance
        if (IsTargetContext(prepared) || IsTargetContext(conflict))
        {
            UpdateBindingText();
        }
    }

    private void OnDeviceChanged(InputDeviceWatcher.InputDeviceCategory _)
    {
        UpdateBindingText();
    }

    private InputAction GetAction()
    {
        return InputBindingManager.Action(actionName);
    }


    private bool IsTargetContext(InputBindingManager.RebindContext ctx)
    {
        if (ctx == null || ctx.action == null) return false;
        var action = GetAction();
        if (action == null) return false;

        // Must match the action
        if (ctx.action != action) return false;

        // If we have a composite part specified, we need to match the binding index
        if (!string.IsNullOrEmpty(compositePartName))
        {
            // Get the binding at the context's index
            if (ctx.bindingIndex < 0 || ctx.bindingIndex >= action.bindings.Count)
                return false;

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

            // Check if the binding's name matches our composite part
            return string.Equals(binding.name, compositePartName, StringComparison.OrdinalIgnoreCase);
        }

        // If no composite part specified, just matching the action is enough
        return true;
    }

    private void OnBtnClicked()
    {
        // Use manager API (we pass part name so manager can pick proper binding if needed)
        InputBindingManager.StartRebind(actionName, string.IsNullOrEmpty(compositePartName) ? null : compositePartName);
    }

    public async void ConfirmPrepared()
    {
        bool ok = await ConfirmPreparedAsync();
        if (!ok) Debug.LogError("ConfirmPrepared: apply failed.");
    }

    private async Task<bool> ConfirmPreparedAsync()
    {
        try
        {
            var task = InputBindingManager.ConfirmApply();
            return await task;
        }
        catch (Exception ex)
        {
            Debug.LogError(ex);
            return false;
        }
    }

    public void CancelPrepared()
    {
        InputBindingManager.DiscardPrepared();
        // UpdateBindingText will be called automatically via OnApply event
    }

    private void UpdateBindingText()
    {
        var action = GetAction();
        if (action == null)
        {
            bindKeyText.text = "<no action>";
            if (targetImage != null) targetImage.sprite = null;
            return;
        }


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


        try
        {
            var deviceCat = InputDeviceWatcher.CurrentCategory;
            InputActionReference refr=default;
            // string controlPath = GlyphService.GetBindingControlPath(action, compositePartName, deviceCat);
            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;
        }
    }
}