using UnityEngine;
using UnityEngine.UI;
using TMPro;
using System;
using System.Collections.Generic;
using UnityEngine.EventSystems;
using DG.Tweening;
using UnityEngine.InputSystem;

namespace Ashwild.Inventory
{
    public class SlotContextMenu : MonoBehaviour
    {
        [Header("References")]
        [SerializeField] private RectTransform panelRect;
        [SerializeField] private CanvasGroup canvasGroup;
        [SerializeField] private Transform buttonContainer;
        [SerializeField] private GameObject buttonPrefab;

        [Header("Settings")]
        [SerializeField] private Vector2 offset = new Vector2(10f, -10f);

        [Header("Animation")]
        [SerializeField] private float showDuration = 0.2f;
        [SerializeField] private float hideDuration = 0.15f;
        [SerializeField] private Ease showEase = Ease.OutBack;
        [SerializeField] private Ease hideEase = Ease.InQuad;

        private int currentSlotIndex = -1;
        private readonly List<GameObject> activeButtons = new List<GameObject>();
        private Canvas rootCanvas;
        private bool isVisible;
        private Tweener scaleTween;
        private Tweener fadeTween;

        private void Awake()
        {
            rootCanvas = GetComponentInParent<Canvas>();
            SetHidden();
        }

        private void SetHidden()
        {
            canvasGroup.gameObject.SetActive(false);
            canvasGroup.alpha = 0f;
            canvasGroup.interactable = false;
            canvasGroup.blocksRaycasts = false;
            panelRect.localScale = Vector3.zero;
        }

        private void OnDestroy()
        {
            scaleTween?.Kill();
            fadeTween?.Kill();
        }

        private void Update()
        {
            if (!isVisible) return;

            Mouse mouse = Mouse.current;
            if (mouse == null) return;

            if (mouse.leftButton.wasPressedThisFrame || mouse.rightButton.wasPressedThisFrame)
            {
                if (!IsPointerOverMenu())
                    Hide();
            }
        }

        public void Show(int slotIndex)
        {
            PlayerInventory inv = PlayerInventory.Instance;
            InventorySlot slot = inv.GetSlot(slotIndex);
            if (slot == null || slot.IsEmpty)
                return;

            // Kill any running animation and clear previous buttons
            scaleTween?.Kill();
            fadeTween?.Kill();
            ClearButtons();

            currentSlotIndex = slotIndex;

            bool isHotbar = slotIndex < inv.HotbarSize;
            bool canSplit = slot.Quantity > 1;

            if (isHotbar)
                AddButton("Move to Inventory", OnMoveToInventory);
            else
                AddButton("Equip", OnEquipToHotbar);

            if (slot.ItemData.ItemType == ItemType.Consumable)
                AddButton("Use", OnUseItem);

            AddButton("Drop", OnDrop);

            if (canSplit)
                AddButton("Split", OnSplit);

            // Activate and position
            canvasGroup.gameObject.SetActive(true);
            Vector2 mousePos = Mouse.current != null ? Mouse.current.position.ReadValue() : Vector2.zero;
            PositionMenu(mousePos);

            // Animate in
            isVisible = true;
            panelRect.localScale = Vector3.one * 0.5f;
            canvasGroup.alpha = 0f;

            scaleTween?.Kill();
            fadeTween?.Kill();

            scaleTween = panelRect.DOScale(1f, showDuration).SetEase(showEase).SetUpdate(true);
            fadeTween = canvasGroup.DOFade(1f, showDuration).SetUpdate(true).OnComplete(() =>
            {
                canvasGroup.interactable = true;
                canvasGroup.blocksRaycasts = true;
            });
        }

        public void Hide()
        {
            if (!isVisible) return;

            isVisible = false;
            canvasGroup.interactable = false;
            canvasGroup.blocksRaycasts = false;

            scaleTween?.Kill();
            fadeTween?.Kill();

            scaleTween = panelRect.DOScale(0f, hideDuration).SetEase(hideEase).SetUpdate(true);
            fadeTween = canvasGroup.DOFade(0f, hideDuration).SetUpdate(true).OnComplete(() =>
            {
                canvasGroup.gameObject.SetActive(false);
                ClearButtons();
                currentSlotIndex = -1;
            });
        }

        private void PositionMenu(Vector2 screenPosition)
        {
            if (rootCanvas == null)
                rootCanvas = GetComponentInParent<Canvas>();

            RectTransform canvasRect = rootCanvas.transform as RectTransform;
            RectTransformUtility.ScreenPointToLocalPointInRectangle(
                canvasRect, screenPosition, rootCanvas.worldCamera, out Vector2 anchoredPos);

            anchoredPos += offset;

            // Clamp to stay within canvas bounds
            Vector2 menuSize = panelRect.sizeDelta;
            Vector2 canvasSize = canvasRect.sizeDelta;
            float halfW = canvasSize.x * 0.5f;
            float halfH = canvasSize.y * 0.5f;

            if (anchoredPos.x + menuSize.x > halfW)
                anchoredPos.x = halfW - menuSize.x;
            if (anchoredPos.y - menuSize.y < -halfH)
                anchoredPos.y = -halfH + menuSize.y;

            panelRect.anchoredPosition = anchoredPos;
        }

        private void AddButton(string label, Action onClick)
        {
            GameObject btnGO = Instantiate(buttonPrefab, buttonContainer);
            btnGO.SetActive(true);

            TextMeshProUGUI text = btnGO.GetComponentInChildren<TextMeshProUGUI>();
            if (text != null)
                text.text = label;

            Button btn = btnGO.GetComponent<Button>();
            if (btn != null)
                btn.onClick.AddListener(() =>
                {
                    onClick?.Invoke();
                    Hide();
                });

            activeButtons.Add(btnGO);
        }

        private void ClearButtons()
        {
            foreach (GameObject btn in activeButtons)
                Destroy(btn);
            activeButtons.Clear();
        }

        private bool IsPointerOverMenu()
        {
            Vector2 mousePos = Mouse.current != null ? Mouse.current.position.ReadValue() : Vector2.zero;
            PointerEventData eventData = new PointerEventData(EventSystem.current)
            {
                position = mousePos
            };
            List<RaycastResult> results = new List<RaycastResult>();
            EventSystem.current.RaycastAll(eventData, results);

            foreach (RaycastResult result in results)
            {
                if (result.gameObject.transform.IsChildOf(transform))
                    return true;
            }
            return false;
        }

        // --- Actions ---

        private void OnEquipToHotbar()
        {
            if (currentSlotIndex < 0) return;
            PlayerInventory inv = PlayerInventory.Instance;

            int targetSlot = inv.SelectedHotbarIndex;
            for (int i = 0; i < inv.HotbarSize; i++)
            {
                if (inv.GetSlot(i).IsEmpty)
                {
                    targetSlot = i;
                    break;
                }
            }

            InventoryUI.OnSwapRequested(currentSlotIndex, targetSlot);
        }

        private void OnMoveToInventory()
        {
            if (currentSlotIndex < 0) return;
            PlayerInventory inv = PlayerInventory.Instance;

            for (int i = inv.HotbarSize; i < inv.InventorySize; i++)
            {
                if (inv.GetSlot(i).IsEmpty)
                {
                    InventoryUI.OnSwapRequested(currentSlotIndex, i);
                    return;
                }
            }

            InventorySlot sourceSlot = inv.GetSlot(currentSlotIndex);
            for (int i = inv.HotbarSize; i < inv.InventorySize; i++)
            {
                InventorySlot slot = inv.GetSlot(i);
                if (!slot.IsEmpty && slot.ItemData == sourceSlot.ItemData && slot.CanAccept(sourceSlot.ItemData))
                {
                    InventoryUI.OnSwapRequested(currentSlotIndex, i);
                    return;
                }
            }
        }

        private void OnUseItem()
        {
            if (currentSlotIndex < 0) return;
            PlayerInventory.Instance.UseItem(currentSlotIndex);
        }

        private void OnDrop()
        {
            if (currentSlotIndex < 0) return;
            PlayerInventory inv = PlayerInventory.Instance;
            InventorySlot slot = inv.GetSlot(currentSlotIndex);
            if (!slot.IsEmpty)
                inv.DropItem(currentSlotIndex, slot.Quantity);
        }

        private void OnSplit()
        {
            if (currentSlotIndex < 0) return;
            PlayerInventory inv = PlayerInventory.Instance;
            InventorySlot slot = inv.GetSlot(currentSlotIndex);
            if (slot.IsEmpty || slot.Quantity <= 1) return;

            int halfQty = slot.Quantity / 2;
            int remaining = slot.Quantity - halfQty;

            for (int i = 0; i < inv.InventorySize; i++)
            {
                if (inv.GetSlot(i).IsEmpty)
                {
                    slot.Set(slot.ItemData, remaining);
                    inv.GetSlot(i).Set(slot.ItemData, halfQty);
                    inv.onSlotChanged?.Invoke(currentSlotIndex);
                    inv.onSlotChanged?.Invoke(i);
                    return;
                }
            }
        }
    }
}