using UnityEngine;
using System;

namespace AibisDream
{
    /// <summary>
    /// 拖拽状态
    /// </summary>
    public enum DragState
    {
        Idle,       // 空闲
        Dragging,   // 拖拽中
        Snapping,   // 吸附中
        Placed      // 已放置
    }

    /// <summary>
    /// 形状拖拽接口
    /// 负责处理形状的拖拽、吸附和放置逻辑
    /// </summary>
    public interface IBlockShapeDragger
    {
        /// <summary>
        /// 当前拖拽状态
        /// </summary>
        DragState CurrentState { get; }

        /// <summary>
        /// 是否可拖拽
        /// </summary>
        bool IsDraggable { get; set; }

        /// <summary>
        /// 目标网格
        /// </summary>
        IBlockPuzzleGrid TargetGrid { get; set; }

        /// <summary>
        /// 吸附距离阈值
        /// </summary>
        float SnapDistance { get; set; }

        /// <summary>
        /// 拖拽开始事件
        /// </summary>
        event Action<IBlockShape> OnDragStart;

        /// <summary>
        /// 拖拽更新事件
        /// </summary>
        event Action<IBlockShape, Vector3> OnDragUpdate;

        /// <summary>
        /// 拖拽结束事件
        /// </summary>
        event Action<IBlockShape, bool> OnDragEnd; // bool表示是否成功放置

        /// <summary>
        /// 吸附事件
        /// </summary>
        event Action<IBlockShape, Vector3, int, int> OnSnap; // 形状, 位置, 网格X, 网格Y

        /// <summary>
        /// 取消吸附事件
        /// </summary>
        event Action<IBlockShape> OnUnsnap;

        /// <summary>
        /// 开始拖拽
        /// </summary>
        void StartDrag();

        /// <summary>
        /// 更新拖拽位置
        /// </summary>
        void UpdateDrag();

        /// <summary>
        /// 结束拖拽
        /// </summary>
        void EndDrag();

        /// <summary>
        /// 取消拖拽（返回原位置）
        /// </summary>
        void CancelDrag();

        /// <summary>
        /// 检查是否可以放置到指定位置
        /// </summary>
        /// <param name="gridX">网格X坐标</param>
        /// <param name="gridY">网格Y坐标</param>
        /// <returns>是否可以放置</returns>
        bool CanPlaceAt(int gridX, int gridY);

        /// <summary>
        /// 获取当前吸附的网格坐标
        /// </summary>
        /// <param name="gridX">输出的网格X坐标</param>
        /// <param name="gridY">输出的网格Y坐标</param>
        /// <returns>是否正在吸附</returns>
        bool GetSnapGridPosition(out int gridX, out int gridY);
    }
}