using UnityEngine;
using System;

public class TextureOffsetDragger : MonoBehaviour
{
    [SerializeField] private float dragThreshold = 10f;
    [SerializeField] private float dragSensitivity = 0.01f;
    [SerializeField] private bool invertXAxis = false;
    [SerializeField] private bool invertYAxis = false;

    private Material material;
    private Vector2 initialMousePosition;
    private Vector2 textureOffset = Vector2.zero;
    private bool isDragging = false;
    private bool isDisabled = true;
    private Camera mainCamera;

    void Start()
    {
        Renderer renderer = GetComponent<Renderer>();
        material = renderer.sharedMaterial;
        mainCamera = Camera.main;
        textureOffset = material.GetVector("_Offset");
    }

    public void SetDragingDisabled(int value)
    {
        isDisabled = Convert.ToBoolean(value);
    }

    void OnMouseDown()
    {
        if (isDisabled) return;

        isDragging = false;
        initialMousePosition = Input.mousePosition;
    }

    void OnMouseDrag()
    {
        if (isDisabled) return;

        Vector2 currentMousePosition = Input.mousePosition;
        float dragDistance = Vector2.Distance(initialMousePosition, currentMousePosition);

        if (!isDragging)
        {
            if (dragDistance > dragThreshold)
            {
                isDragging = true;
            }
            else
            {
                return;
            }
        }

        if (isDragging)
        {
            Vector2 delta = (Vector2)currentMousePosition - initialMousePosition;
            UpdateTextureOffset(delta);
            initialMousePosition = currentMousePosition;
        }
    }

    void OnMouseUp()
    {
        if (isDisabled) return;

        isDragging = false;
    }

    private void UpdateTextureOffset(Vector2 screenDelta)
    {
        // 获取物体的法线方向（假设是平面）
        Vector3 objectNormal = transform.forward;

        // 获取相机的上方向和右方向
        Vector3 cameraUp = mainCamera.transform.up;
        Vector3 cameraRight = mainCamera.transform.right;

        // 将屏幕delta转换为世界空间移动
        Vector3 worldDelta = (cameraRight * screenDelta.x + cameraUp * screenDelta.y) / Screen.width;

        // 计算相对于物体的本地移动
        Vector3 localDelta = transform.InverseTransformDirection(worldDelta);

        // 应用灵敏度和反转设置
        float xMove = localDelta.x * dragSensitivity;
        float yMove = localDelta.y * dragSensitivity;

        xMove *= invertXAxis ? -1 : 1;
        yMove *= invertYAxis ? -1 : 1;

        textureOffset += new Vector2(xMove, yMove);
        material.SetVector("_Offset", textureOffset);
    }
}