using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;

public class SlideGesture : MonoBehaviour
{
    [Header("Slides")]
    public GameObject[] slides;

    [Header("Dot Indicator (opsional)")]
    public Image[] dots;
    public Color dotActive   = Color.white;
    public Color dotInactive = new Color(1, 1, 1, 0.35f);

    [Header("Swipe Setting")]
    public float swipeThreshold = 50f;

    private int   currentIndex = 0;
    private float touchStartY  = 0f;
    private bool  isSwiping    = false;

    void Start()
    {
        ShowSlide(0);
    }

    void Update()
    {
        // Hanya proses swipe kalau panel ini aktif
        if (!gameObject.activeInHierarchy) return;

        // Touch
        if (Input.touchCount > 0)
        {
            Touch t = Input.GetTouch(0);

            // Abaikan kalau touch kena button
            if (EventSystem.current.IsPointerOverGameObject(t.fingerId))
            {
                // Cek apakah yang di-touch adalah slide area, bukan button
                // Kalau kena UI selain slide, biarkan
                if (IsTouchOnButton(t.fingerId))
                {
                    isSwiping = false;
                    return;
                }
            }

            if (t.phase == TouchPhase.Began)
            {
                touchStartY = t.position.y;
                isSwiping   = true;
            }
            else if (t.phase == TouchPhase.Ended && isSwiping)
            {
                float diff = touchStartY - t.position.y;
                ProcessSwipe(diff);
                isSwiping = false;
            }
        }

        // Mouse (Editor)
        if (Input.GetMouseButtonDown(0))
        {
            // Abaikan kalau klik button
            if (!IsPointerOnButton())
            {
                touchStartY = Input.mousePosition.y;
                isSwiping   = true;
            }
        }
        if (Input.GetMouseButtonUp(0) && isSwiping)
        {
            float diff = touchStartY - Input.mousePosition.y;
            ProcessSwipe(diff);
            isSwiping = false;
        }
    }

    void ProcessSwipe(float diff)
    {
        if (diff > swipeThreshold && currentIndex < slides.Length - 1)
            ShowSlide(currentIndex + 1);
        else if (diff < -swipeThreshold && currentIndex > 0)
            ShowSlide(currentIndex - 1);
    }

    // Cek apakah pointer sedang di atas Button
    bool IsPointerOnButton()
    {
        var results = new System.Collections.Generic.List<RaycastResult>();
        var ped     = new PointerEventData(EventSystem.current)
                      { position = Input.mousePosition };
        EventSystem.current.RaycastAll(ped, results);
        foreach (var r in results)
            if (r.gameObject.GetComponent<Button>() != null) return true;
        return false;
    }

    bool IsTouchOnButton(int fingerId)
    {
        var results = new System.Collections.Generic.List<RaycastResult>();
        var ped     = new PointerEventData(EventSystem.current)
                      { position = Input.GetTouch(0).position };
        EventSystem.current.RaycastAll(ped, results);
        foreach (var r in results)
            if (r.gameObject.GetComponent<Button>() != null) return true;
        return false;
    }

    void ShowSlide(int index)
    {
        currentIndex = index;
        for (int i = 0; i < slides.Length; i++)
            slides[i].SetActive(i == currentIndex);

        if (dots != null)
            for (int i = 0; i < dots.Length; i++)
                dots[i].color = i == currentIndex ? dotActive : dotInactive;
    }

    public void ResetToFirst() => ShowSlide(0);
}