using UnityEngine;
using UnityEngine.UI;
using TMPro;
using DG.Tweening;

namespace Ashwild.Inventory
{
    /// <summary>
    /// The fixed description panel shown beside the inventory — a pure view. When the pointer
    /// enters a filled slot the inventory manager hands it an <see cref="ItemDescriptionView"/> and
    /// it fades its CanvasGroup in, drawing the icon, name, description and (for uses-tracked items)
    /// the duration bar. It never reads ItemData or the inventory itself; it renders what it is given.
    /// </summary>
    [DisallowMultipleComponent]
    public class HoverDescriptionUI : MonoBehaviour
    {
        #region Serialized Fields

        [Header("References")]
        [SerializeField] private CanvasGroup canvasGroup;
        [SerializeField] private Image iconImage;
        [SerializeField] private TextMeshProUGUI nameText;
        [SerializeField] private TextMeshProUGUI descriptionText;

        [Header("Duration Bar")]
        [Tooltip("Root object of the duration/uses bar — shown only for items that track uses.")]
        [SerializeField] private GameObject durationBarRoot;
        [Tooltip("Filled image whose fillAmount maps to the remaining uses (Image Type = Filled).")]
        [SerializeField] private Image durationBarFill;
        [Tooltip("Label drawn over the bar, e.g. \"3 / 5\".")]
        [SerializeField] private TextMeshProUGUI durationText;

        [Header("Animation")]
        [SerializeField] private float fadeDuration = 0.15f;

        #endregion

        #region State

        private Tweener fadeTween;

        #endregion

        #region Unity Lifecycle

        /// <summary>
        /// Starts hidden so the panel only appears once a slot is actually hovered.
        /// </summary>
        private void Awake() => SetHidden();

        /// <summary>
        /// Kills the fade tween so it never targets the CanvasGroup after teardown.
        /// </summary>
        private void OnDestroy() => fadeTween?.Kill();

        #endregion

        #region Public API

        /// <summary>
        /// Draws the payload and fades the panel in. Called by the inventory manager on hover enter.
        /// </summary>
        public void Show(ItemDescriptionView view)
        {
            if (iconImage != null)
            {
                iconImage.sprite = view.Icon;
                iconImage.enabled = view.Icon != null;
            }
            if (nameText != null)
                nameText.text = view.Name;
            if (descriptionText != null)
                descriptionText.text = view.Description;

            if (durationBarRoot != null)
                durationBarRoot.SetActive(view.HasDuration);
            if (view.HasDuration)
            {
                if (durationBarFill != null)
                    durationBarFill.fillAmount = view.DurationFill;
                if (durationText != null)
                    durationText.text = view.DurationText;
            }

            fadeTween?.Kill();
            fadeTween = canvasGroup.DOFade(1f, fadeDuration).SetUpdate(true);
        }

        /// <summary>
        /// Fades the panel out via its CanvasGroup only — the GameObject stays active so it can be
        /// shown again instantly. Called on hover exit / inventory close.
        /// </summary>
        public void Hide()
        {
            fadeTween?.Kill();
            fadeTween = canvasGroup.DOFade(0f, fadeDuration).SetUpdate(true);
        }

        #endregion

        #region Internal Helpers

        /// <summary>
        /// Instantly parks the panel invisible via the CanvasGroup, without deactivating it.
        /// </summary>
        private void SetHidden() => canvasGroup.alpha = 0f;

        #endregion
    }
}