using UnityEngine;
using UnityEngine.EventSystems;

/// <summary>
/// Manages layer selection, deselection, and restoring original transforms.
/// Attach to the parent GameObject that contains all layer children.
/// </summary>
public class LayerSelector : MonoBehaviour
{
    [HideInInspector] public Transform selectedLayer = null;

    [Header("Info Panel")]
    public LayerInfoPanel infoPanel;

    // Stored original state per layer index
    private Transform[] layers;
    private Vector3[]   originalPositions;
    private Vector3[]   originalScales;
    private Quaternion[] originalRotations;
    private bool savedOriginal = false;

    void Start()
    {
        int count = transform.childCount;
        layers            = new Transform[count];
        originalPositions = new Vector3[count];
        originalScales    = new Vector3[count];
        originalRotations = new Quaternion[count];

        for (int i = 0; i < count; i++)
            layers[i] = transform.GetChild(i);
    }

    // Call once before the first selection so we capture the "rest" state
    void SaveOriginal()
    {
        if (savedOriginal) return;
        for (int i = 0; i < layers.Length; i++)
        {
            originalPositions[i] = layers[i].localPosition;
            originalScales[i]    = layers[i].localScale;
            originalRotations[i] = layers[i].localRotation;
        }
        savedOriginal = true;
        Debug.Log("[LayerSelector] Original transforms saved.");
    }

    void Update()
    {
        // Ignore clicks/taps that land on UI
        if (EventSystem.current != null && EventSystem.current.IsPointerOverGameObject()) return;

        // --- Touch ---
        if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began)
        {
            Touch touch = Input.GetTouch(0);
            if (EventSystem.current != null && EventSystem.current.IsPointerOverGameObject(touch.fingerId)) return;

            Ray ray = Camera.main.ScreenPointToRay(touch.position);
            if (!TryHitLayer(ray))
                CheckDeselect(ray);
            return;
        }

        // --- Mouse (Editor) ---
        if (Input.GetMouseButtonDown(0))
        {
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            if (!TryHitLayer(ray))
                CheckDeselect(ray);
        }
    }

    // Returns true if a LayerInteract was hit and handled
    bool TryHitLayer(Ray ray)
    {
        if (Physics.Raycast(ray, out RaycastHit hit))
        {
            LayerInteract interact = hit.transform.GetComponent<LayerInteract>();
            if (interact != null)
            {
                interact.TapSelect();
                return true;
            }
        }
        return false;
    }

    void CheckDeselect(Ray ray)
    {
        if (selectedLayer == null) return;

        if (Physics.Raycast(ray, out RaycastHit hit))
        {
            if (!hit.transform.IsChildOf(this.transform))
                Deselect();
        }
        else
        {
            Deselect();
        }
    }

    // ---------------------------------------------------------------
    // PUBLIC API
    // ---------------------------------------------------------------

    public void SelectLayer(Transform layer)
    {
        SaveOriginal();

        // Hide all siblings, show only the selected one
        foreach (Transform l in layers)
            l.gameObject.SetActive(l == layer);

        selectedLayer = layer;

        LayerInteract interact = layer.GetComponent<LayerInteract>();
        interact?.SetSelected(true);

        if (infoPanel != null && interact != null)
            infoPanel.Show(interact.layerTitle, interact.layerDescription, interact.narasiClipIndex);
    }

    public void Deselect()
    {
        for (int i = 0; i < layers.Length; i++)
        {
            layers[i].gameObject.SetActive(true);
            layers[i].localPosition = originalPositions[i];
            layers[i].localRotation = originalRotations[i];
            layers[i].localScale    = originalScales[i];
        }

        foreach (Transform l in layers)
            l.GetComponent<LayerInteract>()?.SetSelected(false);

        if (infoPanel != null) infoPanel.Hide();

        selectedLayer = null;
    }
}