using System;
using AibisDream.Framework;
using UnityEngine;
using UnityEngine.EventSystems;

namespace AibisDream
{
    public class ShapeDragger : MonoBehaviour, IBlockShapeDragger, IInteraction
    {
        [Header("拖拽设置")]
        [SerializeField] private bool isDraggable = true;

        [SerializeField] private float dragScale = 1.1f;

        // 拖拽状态
        private DragState _currentState = DragState.Idle;
        private SnapResult _snapResult;

        // 组件引用
        private BlockShape _blockShape;
        private EventTriggerEx _eventTrigger;

        public DragState CurrentState => _currentState;

        public bool IsDraggable { get => isDraggable; set => isDraggable = value; }
        public IBlockPuzzleGrid TargetGrid => BlockPuzzleSystem.Instance.grid;
        public IBlockShape BlockShape => _blockShape;
        
        // 事件
        public event Action<IBlockShape> OnDragStart;
        public event Action<IBlockShape> OnDragUpdate;
        public event Action<IBlockShape, bool> OnDragEnd;

        private void Awake()
        {
            _blockShape = GetComponent<BlockShape>();
            _eventTrigger = GetComponent<EventTriggerEx>();

            RegisterEvent();
        }

        private void OnDestroy()
        {
            _eventTrigger.UnRegister(EventTriggerType.PointerClick, OnPointerClick);
        }

        private void RegisterEvent()
        {
            _eventTrigger.Register(EventTriggerType.PointerClick, OnPointerClick);
            // _eventTrigger.Register(EventTriggerType.PointerDown, OnPointerDown);
            // _eventTrigger.Register(EventTriggerType.PointerUp, OnPointerUp);
        }

        private void Update()
        {
            if (_currentState == DragState.Dragging)
            {
                UpdateDrag();
            }
        }

        private void OnPointerClick(BaseEventData eventData)
        {
            if (eventData is not PointerEventData { button: PointerEventData.InputButton.Left })
            {
                return;
            }

            // 如果当前物体不在拖拽中则进入拖拽逻辑
            if (_currentState == DragState.Idle || _currentState == DragState.Placed)
            {
                StartDrag();
            }
            // 如果当前物体在拖拽中则取消拖拽
            else
            {
                EndDrag();
            }
        }

        public void StartDrag()
        {
            if (!isDraggable) return;

            // 如果原本就在网格中，则先移除
            TargetGrid?.TryRemoveShapeFromGrid(_blockShape);
            TargetGrid?.ResetPreviewGrid();

            _currentState = DragState.Dragging;

            // 处理层级和缩放
            HandleDragStart();

            OnDragStart?.Invoke(_blockShape);
        }

        private void HandleDragStart()
        {
            // 调整缩放和层级
            transform.localScale = dragScale * Vector3.one;
        }

        public void CancelDrag()
        {
            throw new NotImplementedException();
        }

        public void EndDrag()
        {
            TargetGrid?.ResetPreviewGrid();

            // 如果吸附到了就靠过去
            if (_snapResult.canSnap)
            {
                _currentState = DragState.Placed;
                transform.localScale = Vector3.one;

                TargetGrid.TrySnapToGrid(_blockShape, _snapResult.RootCell);

                // 处理Cursor
                _eventTrigger.OnPointerUp(null);
                OnDragEnd?.Invoke(_blockShape, _currentState == DragState.Placed);
            }

            // TODO: 无法吸附直接不处理

            // else
            // {
            //     _currentState = DragState.Idle;
            //     // transform.position = _originalPosition;
            //     transform.localScale = Vector3.one;

            //     // BlockPuzzleSystem.Instance.shapeRack.RecycleBlockShape(_blockShape);
            // }

            TargetGrid.GridVisualizer.UpdateAllCellsVisual();
        }

        public void UpdateDrag()
        {
            // 检测右键点击进行旋转（仅在拖动中）
            if (Input.GetMouseButtonDown(1)) // 1 = 右键
            {
                _blockShape.RotateClockwise();
            }

            // 更新拖拽位置
            transform.position = GetMouseWorldPosition() - _blockShape.GetCenterPosition();

            // 进行Snap检查
            _snapResult = TargetGrid.CheckSnapToGrid(_blockShape);
            // 在网格显示预览
            TargetGrid.ShowSnapPreview(_snapResult);

            OnDragUpdate?.Invoke(_blockShape);
        }

        private Vector3 GetMouseWorldPosition()
        {
            var mouseWorldPos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
            return new Vector3(mouseWorldPos.x, mouseWorldPos.y, 0);
        }

        // 实现IInteraction接口
        public bool IsActive => true;
        public bool IsAvailable => true;
        public GameObject GetGameObject() => gameObject;
    }
}