using UnityEngine;

public class HpBar : MonoBehaviour
{
    [SerializeField] private Health _health;
    [SerializeField] private Transform _fill;
    [SerializeField] private bool _autoFindHealthInParent = true;
    [SerializeField] private bool _hideWhenFull = true;
    [SerializeField] private float _smoothSpeed = 0f;

    [Header("Color Thresholds")]
    [SerializeField] private Color _highColor = new Color(0.2f, 0.9f, 0.3f, 1f);
    [SerializeField] private Color _midColor = new Color(1f, 0.85f, 0.2f, 1f);
    [SerializeField] private Color _lowColor = new Color(0.95f, 0.25f, 0.25f, 1f);
    [SerializeField, Range(0f, 1f)] private float _midThreshold = 0.5f;
    [SerializeField, Range(0f, 1f)] private float _lowThreshold = 0.2f;

    private Vector3 _baseFillScale;
    private SpriteRenderer _fillRenderer;
    private float _currentRatio = 1f;
    private float _targetRatio = 1f;

    private void Awake()
    {
        if (_health == null && _autoFindHealthInParent)
            _health = GetComponentInParent<Health>();

        if (_fill != null)
        {
            _baseFillScale = _fill.localScale;
            _fillRenderer = _fill.GetComponent<SpriteRenderer>();
        }
    }

    private void OnEnable()
    {
        if (_health == null) return;

        _health.OnHealthChanged += HandleHealthChanged;
        HandleHealthChanged(_health.CurrentHealth, _health.MaxHealth);
    }

    private void OnDisable()
    {
        if (_health != null)
            _health.OnHealthChanged -= HandleHealthChanged;
    }

    private void Update()
    {
        if (_smoothSpeed <= 0f) return;
        if (Mathf.Approximately(_currentRatio, _targetRatio)) return;

        _currentRatio = Mathf.MoveTowards(_currentRatio, _targetRatio, _smoothSpeed * Time.deltaTime);
        ApplyScale();
    }

    private void HandleHealthChanged(int current, int max)
    {
        _targetRatio = max > 0 ? (float)current / max : 0f;

        if (_smoothSpeed <= 0f)
        {
            _currentRatio = _targetRatio;
            ApplyScale();
        }

        ApplyColor(_targetRatio);

        if (_hideWhenFull && _fill != null)
        {
            bool shouldShow = _targetRatio < 1f && _targetRatio > 0f;
            if (gameObject.activeSelf != shouldShow)
                gameObject.SetActive(shouldShow);
        }
    }

    private void ApplyScale()
    {
        if (_fill == null) return;

        Vector3 scale = _baseFillScale;
        scale.x = _baseFillScale.x * Mathf.Clamp01(_currentRatio);
        _fill.localScale = scale;
    }

    private void ApplyColor(float ratio)
    {
        if (_fillRenderer == null) return;

        Color color;
        if (ratio <= _lowThreshold)
            color = _lowColor;
        else if (ratio <= _midThreshold)
            color = _midColor;
        else
            color = _highColor;

        _fillRenderer.color = color;
    }
}