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

namespace AibisDream
{
    public class ShapeDragger : MonoBehaviour, IBlockShapeDragger, IInteraction
    {
        #region 编辑器字段
        [SerializeField] private bool isDraggable = true;

        [SerializeField] private int dragLayerId;
        [SerializeField] private int dragLayerOrder;

        [SerializeField] private int idleLayerId;
        [SerializeField] private int idleLayerOrder;
        
        [Header("长按设置")]
        [SerializeField] private float longPressDuration = 0.65f;
        [SerializeField] private float longPressScale = 1.1f;
        [SerializeField] private float shakeIntensity = 0.1f;
        #endregion

        // 拖拽状态
        private DragState _currentState = DragState.Placed;
        public DragState CurrentState
        {
            get => _currentState;
            set
            {
                if (value == _currentState) return;
                // 处理状态切换
                HandleStateChange(value);
                _currentState = value;
            }
        }
        private SnapResult _snapResult;
        
        // 长按相关状态
        private bool _isPressing;
        private bool _isLongPressTriggered;
        private Coroutine _longPressCoroutine;
        private Vector3 _originalScale;
        private Vector3 _originalPosition;

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

        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.PointerDown, OnPointerDown);
            _eventTrigger.UnRegister(EventTriggerType.PointerUp, OnPointerUp);
            _eventTrigger.UnRegister(EventTriggerType.PointerClick, OnPointerClick);
            
            // 清理协程
            if (_longPressCoroutine != null)
            {
                StopCoroutine(_longPressCoroutine);
                _longPressCoroutine = null;
            }
        }

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

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

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

            // 只有在静止状态才能开始长按
            if (CurrentState == DragState.Idle || CurrentState == DragState.Placed)
            {
                _isPressing = true;
                _isLongPressTriggered = false;
                _longPressCoroutine = StartCoroutine(LongPressCoroutine());
            }
        }
        
        private void OnPointerUp(BaseEventData eventData)
        {
            if (eventData is not PointerEventData { button: PointerEventData.InputButton.Left })
            {
                return;
            }

            // 如果还在长按过程中（未完成），则取消
            if (_isPressing && !_isLongPressTriggered)
            {
                CancelLongPress();
            }
        }
        
        private void OnPointerClick(BaseEventData eventData)
        {
            if (eventData is not PointerEventData { button: PointerEventData.InputButton.Left })
            {
                return;
            }

            // 只有在拖拽中点击才结束拖拽
            if (CurrentState == DragState.Dragging && _isLongPressTriggered)
            {
                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;

            OnDragStart?.Invoke(_blockShape);
        }

        public void EndDrag()
        {
            // 清理长按状态
            CancelLongPress();
            
            // 先吸附到回收槽
            var recycled = BlockPuzzleSystem.Instance.TrySnapToRecycleSlot(_blockShape);
            if (recycled)
            {
                CurrentState = DragState.Idle;
                _snapResult = SnapResult.RecycleResult;
                TargetGrid.ShowSnapPreview(_snapResult);
                OnDragEnd?.Invoke(_blockShape, CurrentState == DragState.Placed);
                return;
            }

            // 再吸附到网格
            TargetGrid?.ResetPreviewGrid();
            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);
            }
            else
            {
                // 都没吸附到，恢复原状态和缩放
                transform.localScale = Vector3.one;
            }

            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 void HandleStateChange(DragState newState)
        {
            var sortingGroup = _blockShape?.SortingGroup;
            if (sortingGroup == null) return;
            
            switch (newState)
            {
                case DragState.Idle:
                case DragState.Dragging:
                    sortingGroup.sortingOrder = dragLayerOrder;
                    sortingGroup.sortingLayerID = dragLayerId;
                    break;
                case DragState.Placed:
                    sortingGroup.sortingOrder = idleLayerOrder;
                    sortingGroup.sortingLayerID = idleLayerId;
                    break;
            }
        }

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

        private IEnumerator LongPressCoroutine()
        {
            float elapsed = 0f;
            _originalScale = transform.localScale;
            _originalPosition = transform.localPosition;
            
            while (elapsed < longPressDuration)
            {
                elapsed += Time.deltaTime;
                float progress = elapsed / longPressDuration;
                
                // 抖动效果（轻微）
                float shake = Mathf.Sin(elapsed * 30f) * shakeIntensity * progress;
                transform.localPosition = _originalPosition + Vector3.right * shake;
                
                // 放大效果（缓慢 EaseOut）
                float scale = Mathf.Lerp(1f, longPressScale, EaseOutQuad(progress));
                transform.localScale = _originalScale * scale;
                
                yield return null;
            }
            
            // 完成长按，开始拖拽
            _isLongPressTriggered = true;
            StartDrag();
        }
        
        private float EaseOutQuad(float t)
        {
            return t * (2f - t);
        }
        
        private void CancelLongPress()
        {
            if (_longPressCoroutine != null)
            {
                StopCoroutine(_longPressCoroutine);
                _longPressCoroutine = null;
            }
            
            // 恢复原始状态
            if (_isPressing && !_isLongPressTriggered)
            {
                transform.localScale = _originalScale;
                transform.localPosition = _originalPosition;
            }
            
            _isPressing = false;
            _isLongPressTriggered = false;
        }

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