using UnityEngine;

public class Draw2DNavigation : MonoBehaviour
{
    [Header("Cible à zoomer / déplacer (UI root)")]
    public Transform Draw2D;

    [Header("Limites de zoom")]
    public float minScale = 0.3f;
    public float maxScale = 8f;

    [Header("Vitesses de zoom")]
    public float mouseZoomSpeed = 1.0f;     // zoom molette
    public float pinchZoomSpeed = 0.005f;   // zoom pinch 2 doigts

    [Header("Vitesses de pan (déplacement)")]
    public float mousePanSpeed = 1.0f;      // pan souris
    public float touchPanSpeed = 1.0f;      // pan touch

    private bool isPanningMouse = false;
    private Vector3 lastMousePanPosition;

    void Update()
    {
        if (WallPoint.AnyPointDragging)
        return;
        HandleMouseZoom();
        HandleMousePan();
        HandleTouchZoomAndPan();
    }

    // ---------- ZOOM SOURIS (PC / Laptop) ----------
    void HandleMouseZoom()
    {
        float scroll = Input.GetAxis("Mouse ScrollWheel");

        if (Mathf.Abs(scroll) > 0.0001f && MouseCheck.InOut())
        {
            float factor = 1f + scroll * mouseZoomSpeed;
            ApplyZoomFactor(factor);
        }
    }

    // ---------- PAN SOURIS (drag bouton gauche) ----------
    void HandleMousePan()
    {
        // on bloque le pan souris si on est sur mobile (optionnel mais propre)
        #if UNITY_EDITOR || UNITY_STANDALONE || UNITY_WEBGL
        if (Input.touchCount > 0) return; // si touch actif, on évite conflit
        #endif

        // début du drag
        if (Input.GetMouseButtonDown(1) && MouseCheck.InOut())
        {
            isPanningMouse = true;
            lastMousePanPosition = Input.mousePosition;
        }

        // drag en cours
        if (Input.GetMouseButton(1) && isPanningMouse)
        {
            Vector3 currentMousePos = Input.mousePosition;
            Vector3 delta = currentMousePos - lastMousePanPosition;
            lastMousePanPosition = currentMousePos;

            // déplacement en écran → translation du Draw2D
            Pan(delta * mousePanSpeed);
        }

        // fin du drag
        if (Input.GetMouseButtonUp(0))
        {
            isPanningMouse = false;
        }
    }

    // ---------- TOUCH : PINCH ZOOM + PAN 1 DOIGT ----------
    void HandleTouchZoomAndPan()
    {
        // Aucun touch → rien à faire
        if (Input.touchCount == 0)
            return;

        // --- PINCH 2 DOIGTS ---
        if (Input.touchCount == 2)
        {
            Touch touchZero = Input.GetTouch(0);
            Touch touchOne  = Input.GetTouch(1);

            Vector2 prevPosZero = touchZero.position - touchZero.deltaPosition;
            Vector2 prevPosOne  = touchOne.position - touchOne.deltaPosition;

            float prevMagnitude    = (prevPosZero - prevPosOne).magnitude;
            float currentMagnitude = (touchZero.position - touchOne.position).magnitude;

            float difference = currentMagnitude - prevMagnitude; // > 0 = zoom in

            float factor = 1f + (difference * pinchZoomSpeed);
            ApplyZoomFactor(factor);

            // quand 2 doigts, on ne pan pas
            return;
        }

        // --- PAN 1 DOIGT ---
        if (Input.touchCount == 1)
        {
            Touch touch = Input.GetTouch(0);

            if (touch.phase == TouchPhase.Moved)
            {
                Vector2 delta = touch.deltaPosition;
                Pan(delta * touchPanSpeed);
            }
        }
    }

    // ---------- APPLIQUER LE ZOOM ----------
    void ApplyZoomFactor(float factor)
    {
        if (Draw2D == null) return;

        Vector3 currentScale = Draw2D.localScale;
        float newScale = currentScale.x * factor;
        newScale = Mathf.Clamp(newScale, minScale, maxScale);

        Draw2D.localScale = new Vector3(newScale, newScale, 1f);
    }

    // ---------- APPLIQUER LE PAN ----------
    void Pan(Vector2 screenDelta)
    {
        if (Draw2D == null) return;

        // Pour un Canvas en Screen Space Overlay,
        // déplacer directement la position fonctionne bien.
        // On peut inverser l’axe Y si le sens est inversé.
        Vector3 delta = new Vector3(screenDelta.x, screenDelta.y, 0f);

        Draw2D.position += delta;
    }
}