using Inventory;
using System.Collections.Generic;
using TMPro;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.InputSystem; // 引入 Input System
using Player;

public class InventoryUI : MonoBehaviour
{
    [Header("Player References")]
    public HandController handController; // 拖入 Player 身上的脚本
    public PlayerInput playerInput;       // 拖入 Player 身上的 PlayerInput 组件

    [Header("UI References")]
    public Transform hotbarPanel;       // ���� HotbarPanel
    public GameObject slotPrefab;       // ���������õ� Hotbar_Slot Prefab

    [Header("Settings")]
    public Color selectedColor = new Color(0f, 1f, 1f, 0.5f); // ѡ��ʱ�ı߿���ɫ��������ɫ��͸����
    public Color normalColor = new Color(0f, 1f, 1f, 0f);     // δѡ��ʱ�ı߿���ɫ��͸����

    // �ڲ��ࣺ�����������ӵ� UI ���ã�����ÿ�� GetComponent
    private class SlotUI
    {
        public GameObject instance;
        public Image icon;
        public TextMeshProUGUI amountText;
        public Image frame; // �ñ߿���ɫ����ʾѡ��״̬
    }

    private List<SlotUI> slots = new List<SlotUI>();
    private InputAction hotbar1Action;
    private InputAction hotbar2Action;
    private InputAction hotbar3Action;
    private InputAction hotbar4Action;
    private InputAction dropAction;

    private System.Action<InputAction.CallbackContext> hotbar1Handler;
    private System.Action<InputAction.CallbackContext> hotbar2Handler;
    private System.Action<InputAction.CallbackContext> hotbar3Handler;
    private System.Action<InputAction.CallbackContext> hotbar4Handler;
    private System.Action<InputAction.CallbackContext> dropHandler;

    private void Awake()
    {
        if (handController == null)
        {
            handController = FindObjectOfType<HandController>(true);
        }

        if (playerInput == null)
        {
            var pc = FindObjectOfType<PlayerController>(true);
            if (pc != null)
            {
                playerInput = pc.GetComponent<PlayerInput>();
            }

            if (playerInput == null)
            {
                playerInput = FindObjectOfType<PlayerInput>(true);
            }
        }
    }

    private void Start()
    {
        TryInitializeUI();
    }

    private void OnEnable()
    {
        if (hotbar1Handler == null) hotbar1Handler = _ => SelectSlot(0);
        if (hotbar2Handler == null) hotbar2Handler = _ => SelectSlot(1);
        if (hotbar3Handler == null) hotbar3Handler = _ => SelectSlot(2);
        if (hotbar4Handler == null) hotbar4Handler = _ => SelectSlot(3);
        if (dropHandler == null) dropHandler = OnDropItem;

        if (playerInput == null)
        {
            Debug.LogError("[InventoryUI] PlayerInput 未赋值，无法绑定 Hotbar/Drop 输入。请在 Inspector 里拖入玩家身上的 PlayerInput。");
            return;
        }

        if (playerInput.currentActionMap != null && playerInput.currentActionMap.name != "Player")
        {
            Debug.LogWarning($"[InventoryUI] 当前 ActionMap 为 '{playerInput.currentActionMap.name}'，Hotbar/Drop 可能不会触发。");
        }

        if (playerInput != null)
        {
            // 订阅 Hotbar 切换事件
            // 注意：Action 名字必须和你 Input Actions 里的一模一样
            hotbar1Action = playerInput.actions["Hotbar1"];
            if (hotbar1Action != null) hotbar1Action.performed += hotbar1Handler;
            else Debug.LogError("[InventoryUI] 找不到名为 'Hotbar1' 的 Action，请检查 Input Actions。");

            hotbar2Action = playerInput.actions["Hotbar2"];
            if (hotbar2Action != null) hotbar2Action.performed += hotbar2Handler;
            else Debug.LogError("[InventoryUI] 找不到名为 'Hotbar2' 的 Action，请检查 Input Actions。");

            hotbar3Action = playerInput.actions["Hotbar3"];
            if (hotbar3Action != null) hotbar3Action.performed += hotbar3Handler;
            else Debug.LogError("[InventoryUI] 找不到名为 'Hotbar3' 的 Action，请检查 Input Actions。");

            hotbar4Action = playerInput.actions["Hotbar4"];
            if (hotbar4Action != null) hotbar4Action.performed += hotbar4Handler;
            else Debug.LogError("[InventoryUI] 找不到名为 'Hotbar4' 的 Action，请检查 Input Actions。");
            
            // 订阅丢弃事件
            dropAction = playerInput.actions["Drop"];
            if (dropAction != null) dropAction.performed += dropHandler;
            else Debug.LogError("[InventoryUI] 找不到名为 'Drop' 的 Action，请检查 Input Actions。");
        }
    }

    private void OnDisable()
    {
        // 取消订阅，防止内存泄漏
        if (hotbar1Action != null && hotbar1Handler != null) hotbar1Action.performed -= hotbar1Handler;
        if (hotbar2Action != null && hotbar2Handler != null) hotbar2Action.performed -= hotbar2Handler;
        if (hotbar3Action != null && hotbar3Handler != null) hotbar3Action.performed -= hotbar3Handler;
        if (hotbar4Action != null && hotbar4Handler != null) hotbar4Action.performed -= hotbar4Handler;
        if (dropAction != null && dropHandler != null) dropAction.performed -= dropHandler;

        hotbar1Action = null;
        hotbar2Action = null;
        hotbar3Action = null;
        hotbar4Action = null;
        dropAction = null;
    }

    private void Update()
    {
        TryInitializeUI();
        if (isInitialized)
        {
            RefreshUI();
        }
    }

    private bool isInitialized;

    private void TryInitializeUI()
    {
        if (isInitialized) return;
        if (InventorySystem.Instance == null) return;
        InitializeUI();
        isInitialized = true;
    }

    private void InitializeUI()
    {
        if (hotbarPanel == null || slotPrefab == null)
        {
            Debug.LogError("[InventoryUI] 缺少 HotbarPanel 或 SlotPrefab 引用！请在 Inspector 中赋值。");
            return;
        }

        // 1. 清理现有的子物体（比如你在编辑器里复制的那 5 个测试格子）
        foreach (Transform child in hotbarPanel)
        {
            Destroy(child.gameObject);
        }
        slots.Clear();

        // 2. 根据 InventorySystem 的最大槽位生成格子
        // 如果 InventorySystem 还没准备好，我们默认生成 5 个
        int slotCount = InventorySystem.Instance != null ? InventorySystem.Instance.maxSlots : 5;
        Debug.Log($"[InventoryUI] 正在生成 {slotCount} 个格子...");

        for (int i = 0; i < slotCount; i++)
        {
            GameObject newSlot = Instantiate(slotPrefab, hotbarPanel);
            
            SlotUI ui = new SlotUI();
            ui.instance = newSlot;

            // 使用递归查找，这样即使层级稍微深一点也能找到
            ui.icon = FindChild<Image>(newSlot.transform, "Icon");
            ui.amountText = FindChild<TextMeshProUGUI>(newSlot.transform, "AmountText");
            ui.frame = FindChild<Image>(newSlot.transform, "Frame");

            if (ui.icon == null) Debug.LogError($"[InventoryUI] 格子 {i} 找不到名为 'Icon' 的 Image 组件！");
            if (ui.amountText == null) Debug.LogError($"[InventoryUI] 格子 {i} 找不到名为 'AmountText' 的 TMP 组件！");

            // 默认隐藏图标和文字，并重置颜色为不透明
            if (ui.icon != null)
            {
                ui.icon.color = Color.white;
                ui.icon.sprite = null;
                ui.icon.gameObject.SetActive(false);
            }
            if (ui.amountText != null) ui.amountText.gameObject.SetActive(false);

            slots.Add(ui);
        }

        // 3. 初始化默认选择第一个格子
        SelectSlot(0);
    }

    // 辅助方法：递归查找子物体组件
    private T FindChild<T>(Transform parent, string name) where T : Component
    {
        foreach (Transform child in parent)
        {
            if (child.name == name) return child.GetComponent<T>();
            T found = FindChild<T>(child, name);
            if (found != null) return found;
        }
        return null;
    }

    // 记录上一次当前选中格子的物品数据，用于检测是否捡到了新东西
    private ItemData lastSelectedItemData = null;

    private void RefreshUI()
    {
        if (InventorySystem.Instance == null) return;

        List<InventoryItem> items = InventorySystem.Instance.inventory;

        // 检查当前选中格子的物品是否发生了变化
        if (currentSelection >= 0 && currentSelection < items.Count)
        {
            InventoryItem currentItem = items[currentSelection];
            ItemData currentData = currentItem?.data;

            // 如果物品数据变了（比如从 null 变成了 Apple，或者从 Apple 换成了 Bottle）
            // 并且当前没有强制收手，就自动刷新手中的模型
            if (currentData != lastSelectedItemData)
            {
                lastSelectedItemData = currentData;
                if (!isHandHidden)
                {
                    UpdateHandItem();
                }
            }
        }

        for (int i = 0; i < slots.Count; i++)
        {
            InventoryItem item = i < items.Count ? items[i] : null;
            ItemData data = item != null ? item.data : null;
            Sprite iconSprite = data != null ? data.icon : null;

            bool hasRenderableItem = data != null && iconSprite != null;

            if (slots[i].icon != null)
            {
                if (hasRenderableItem)
                {
                    slots[i].icon.sprite = iconSprite;
                    slots[i].icon.color = Color.white;
                    slots[i].icon.gameObject.SetActive(true);
                }
                else
                {
                    slots[i].icon.sprite = null;
                    slots[i].icon.gameObject.SetActive(false);
                }
            }

            if (slots[i].amountText != null)
            {
                if (data != null && item != null && item.stackSize > 1)
                {
                    slots[i].amountText.gameObject.SetActive(true);
                    slots[i].amountText.text = item.stackSize.ToString();
                }
                else
                {
                    slots[i].amountText.text = string.Empty;
                    slots[i].amountText.gameObject.SetActive(false);
                }
            }
        }
    }

    // 丢弃物品的逻辑桩
    private void OnDropItem(InputAction.CallbackContext context)
    {
        if (currentSelection < 0 || InventorySystem.Instance == null) return;

        // 检查当前格子有没有东西
        if (currentSelection < InventorySystem.Instance.inventory.Count)
        {
            var item = InventorySystem.Instance.inventory[currentSelection];
            if (item != null && item.data != null)
            {
                Debug.Log($"[Input] 按下了 G 键，准备丢弃: {item.data.name}");
                
                // 1. 在玩家前方生成掉落物
                if (item.data.pickupPrefab != null)
                {
                    // 优先使用 HandController 的位置（即 Player 位置）作为基准
                    // 如果能获取到具体的 handPosition（手的位置）则更好，否则用 Player 身体位置
                    Transform origin = handController != null ? handController.transform : transform;
                    
                    // 如果 handController 有定义 handPosition，尽量用它，因为它通常在摄像机附近
                    if (handController != null && handController.handPosition != null)
                    {
                        origin = handController.handPosition;
                    }

                    // 在起点前方 0.5 米处生成（避免穿模）
                    Vector3 spawnPos = origin.position + origin.forward * 0.5f;
                    
                    GameObject droppedObj = Instantiate(item.data.pickupPrefab, spawnPos, Quaternion.identity);

                    // 1.5 如果有 ItemPhysicsState，强制解除可能存在的 startKinematic 锁定
                    var physState = droppedObj.GetComponent<Project.Interaction.ItemPhysicsState>();
                    if (physState != null)
                    {
                        physState.ReleaseKinematic();
                    }

                    // 2. 如果有刚体，给它一个向前的力（扔出去的感觉）
                    Rigidbody rb = droppedObj.GetComponent<Rigidbody>();
                    if (rb != null)
                    {
                        // 确保物理完全启用（作为最后保障）
                        rb.isKinematic = false;
                        rb.useGravity = true;

                        // 随机一点旋转，更自然
                        rb.AddTorque(Random.insideUnitSphere * 5f);
                        // 使用 origin.forward 确保是向当前朝向扔出
                        rb.AddForce(origin.forward * 4f + Vector3.up * 1.5f, ForceMode.Impulse);
                    }
                }
                else
                {
                    Debug.LogWarning($"[Inventory] 物品 {item.data.name} 缺少 PickupPrefab，无法在场景中生成掉落物！只会在背包中移除。");
                }

                // 3. 从背包中移除 1 个
                InventorySystem.Instance.RemoveFromSlot(currentSelection, 1);
                
                // 4. 手部模型更新会由 RefreshUI 自动处理
            }
            else
            {
                Debug.Log("[Input] 当前格子是空的，无法丢弃。");
            }
        }
    }

    private int currentSelection = -1;
    private bool isHandHidden = false; // 记录当前是否强制收手

    private void SelectSlot(int index)
    {
        if (index < 0 || index >= slots.Count) return;

        // 如果再次按下当前选中的格子 -> 切换收手/拿出状态
        if (index == currentSelection)
        {
            isHandHidden = !isHandHidden;
            UpdateHandItem(); // 更新手部显示
            return;
        }

        // 切换到了新格子
        currentSelection = index;
        isHandHidden = false; // 重置收手状态，默认拿出新物品
        
        // 同步选中状态给 InventorySystem
        if (InventorySystem.Instance != null)
        {
            InventorySystem.Instance.selectedSlotIndex = index;
        }

        // 更新高亮显示
        for (int i = 0; i < slots.Count; i++)
        {
            if (slots[i].frame != null)
            {
                slots[i].frame.color = (i == index) ? selectedColor : normalColor;
            }
        }

        UpdateHandItem();
        Debug.Log($"选择了第 {index + 1} 个格子");
    }

    // 独立出来的更新手部物品方法
    private void UpdateHandItem()
    {
        if (handController == null || InventorySystem.Instance == null) return;

        // 如果强制收手，直接传 null
        if (isHandHidden)
        {
            handController.EquipItem(null);
            return;
        }

        // 否则尝试装备当前选中格子的物品
        if (currentSelection >= 0 && currentSelection < InventorySystem.Instance.inventory.Count)
        {
            var item = InventorySystem.Instance.inventory[currentSelection];
            handController.EquipItem(item != null ? item.data : null);
        }
        else
        {
            handController.EquipItem(null);
        }
    }
}