using UnityEngine;

public sealed class FurnaceMetalLevelView : MonoBehaviour
{
    [SerializeField] private FurnaceController furnace;
    [SerializeField] private Transform metalVisual;
    [SerializeField] private Transform emptyLocalPosition;
    [SerializeField] private Transform fullLocalPosition;
    [SerializeField, Min(0f)] private float movementSpeed = 1.5f;

    private Vector3 targetLocalPosition;

    private void Reset()
    {
        furnace = GetComponentInParent<FurnaceController>();
        metalVisual = transform;
    }

    private void OnEnable()
    {
        if (furnace == null)
            furnace = GetComponentInParent<FurnaceController>();

        if (furnace != null)
            furnace.Changed += RefreshTarget;

        RefreshTarget();
    }

    private void OnDisable()
    {
        if (furnace != null)
            furnace.Changed -= RefreshTarget;
    }

    private void Update()
    {
        if (metalVisual == null)
            return;

        metalVisual.localPosition = movementSpeed <= 0f
            ? targetLocalPosition
            : Vector3.MoveTowards(
                metalVisual.localPosition,
                targetLocalPosition,
                movementSpeed * Time.deltaTime);
    }

    private void RefreshTarget()
    {
        float normalized = furnace != null ? furnace.MetalNormalized : 0f;
        targetLocalPosition = Vector3.Lerp(
            GetLocalPoint(emptyLocalPosition),
            GetLocalPoint(fullLocalPosition),
            normalized);
    }

    private Vector3 GetLocalPoint(Transform point)
    {
        if (point == null || metalVisual == null)
            return metalVisual != null ? metalVisual.localPosition : Vector3.zero;

        Transform space = metalVisual.parent;
        return space != null
            ? space.InverseTransformPoint(point.position)
            : point.position;
    }

    [ContextMenu("Preview/Empty")]
    private void PreviewEmpty() => ApplyPreview(0f);

    [ContextMenu("Preview/Half")]
    private void PreviewHalf() => ApplyPreview(0.5f);

    [ContextMenu("Preview/Full")]
    private void PreviewFull() => ApplyPreview(1f);

    private void ApplyPreview(float normalized)
    {
        if (metalVisual == null)
            return;

        metalVisual.localPosition = Vector3.Lerp(
            GetLocalPoint(emptyLocalPosition),
            GetLocalPoint(fullLocalPosition),
            normalized);
    }
}