using UnityEngine;

public class CameraDragMove : MonoBehaviour
{
    public ShowPanel m_ShowPanel;
    public Camera cam;                  // 이동시킬 카메라
    public SpriteRenderer targetSprite; // 영역 기준이 되는 스프라이트
    public GameObject go_btnbg;
    public float dragSpeed = 1f;

    private Vector3 lastTouchPos;
    Vector3 lastcamPos;
    private bool isDragging = false;

    void Reset()
    {
        cam = Camera.main;
    }

    void Update()
    {
#if UNITY_EDITOR || UNITY_STANDALONE
        if (Input.GetMouseButtonDown(0) || Input.GetMouseButton(0) || Input.GetMouseButtonUp(0))
        {
            ProcessInput(
                Input.GetMouseButtonDown(0),
                Input.GetMouseButton(0),
                Input.GetMouseButtonUp(0),
                Input.mousePosition
            );
        }
#else
    if (Input.touchCount == 1)
    {
        Touch touch = Input.GetTouch(0);
        ProcessInput(
            touch.phase == TouchPhase.Began,
            touch.phase == TouchPhase.Moved,
            touch.phase == TouchPhase.Ended,
            touch.position
        );
    }
#endif
    }

    void ProcessInput(bool began, bool moved, bool ended, Vector3 position)
    {
        if (began)
        {
            lastTouchPos = position;
            lastcamPos = cam.transform.position;
            isDragging = false;
        }
        else if (moved)
        {
            Vector3 deltaWorld = cam.ScreenToWorldPoint(position) - cam.ScreenToWorldPoint(lastTouchPos);
            deltaWorld.z = 0f;

            cam.transform.position -= deltaWorld * dragSpeed;
            ClampCameraPosition();

            lastTouchPos = position;

            if (lastcamPos != cam.transform.position || Mathf.Abs(deltaWorld.x) >= 0.01f || Mathf.Abs(deltaWorld.y) >= 0.01f)
                isDragging = true;
        }
        else if (ended)
        {
            if (!isDragging)
                m_ShowPanel.OnClick_Btn(4);
        }
    }

    void ClampCameraPosition()
    {
        if (targetSprite == null) return;

        Bounds spriteBounds = targetSprite.bounds;
        float camHeight = cam.orthographicSize * 2f;
        float camWidth = camHeight * cam.aspect;

        Vector3 pos = cam.transform.position;

        // sprite가 카메라보다 작은 경우 → 카메라를 가운데 고정
        if (camWidth >= spriteBounds.size.x || camHeight >= spriteBounds.size.y)
        {
            pos.x = spriteBounds.center.x;
            pos.y = spriteBounds.center.y;
        }
        else
        {
            float minX = spriteBounds.min.x + camWidth / 2f;
            float maxX = spriteBounds.max.x - camWidth / 2f;
            float minY = spriteBounds.min.y + camHeight / 2f;
            float maxY = spriteBounds.max.y - camHeight / 2f;

            pos.x = Mathf.Clamp(pos.x, minX, maxX);
            pos.y = Mathf.Clamp(pos.y, minY, maxY);
        }

        cam.transform.position = pos;
    }
}