using UnityEngine;
using UnityEngine.UI;

namespace GeometryTD.UI
{
    public class TowerRepoItem : RepoItem
    {
        private static readonly Vector2 DefaultTowerDragGhostSize = new Vector2(64f, 64f);

        public new TowerRepoItemContext Context => base.Context as TowerRepoItemContext;

        public void OnInit(TowerRepoItemContext context)
        {
            base.OnInit(context);
        }

        protected override bool CreateDragGhost()
        {
            DestroyDragGhost();

            if (DragRoot == null)
            {
                return false;
            }

            TowerIconArea towerIconArea = IconArea as TowerIconArea;
            if (towerIconArea == null)
            {
                return base.CreateDragGhost();
            }

            _dragGhostObject = new GameObject("TowerRepoItemDragGhost", typeof(RectTransform), typeof(CanvasGroup));
            _dragGhostObject.layer = gameObject.layer;

            _dragGhostRect = _dragGhostObject.GetComponent<RectTransform>();
            _dragGhostRect.SetParent(DragRoot, false);
            _dragGhostRect.anchorMin = new Vector2(0.5f, 0.5f);
            _dragGhostRect.anchorMax = new Vector2(0.5f, 0.5f);
            _dragGhostRect.pivot = new Vector2(0.5f, 0.5f);

            Vector2 iconSize = IconArea != null ? IconArea.CurrentIconSize : Vector2.zero;
            if (iconSize.x <= 0f || iconSize.y <= 0f)
            {
                iconSize = BackgroundImage != null ? BackgroundImage.rectTransform.rect.size : DefaultTowerDragGhostSize;
            }

            if (iconSize.x <= 0f || iconSize.y <= 0f)
            {
                iconSize = DefaultTowerDragGhostSize;
            }

            _dragGhostRect.sizeDelta = iconSize;

            bool hasAnyLayer = false;
            hasAnyLayer |= TryCreateLayer("Base", towerIconArea.BaseIconSprite, towerIconArea.BaseIconColor,
                towerIconArea.BaseIconMaterial, _dragGhostRect, 0);
            hasAnyLayer |= TryCreateLayer("Bearing", towerIconArea.BearingIconSprite, towerIconArea.BearingIconColor,
                towerIconArea.BearingIconMaterial, _dragGhostRect, 1);
            hasAnyLayer |= TryCreateLayer("Muzzle", towerIconArea.MuzzleIconSprite, towerIconArea.MuzzleIconColor,
                towerIconArea.MuzzleIconMaterial, _dragGhostRect, 2);

            if (!hasAnyLayer)
            {
                DestroyDragGhost();
                return base.CreateDragGhost();
            }

            CanvasGroup ghostCanvasGroup = _dragGhostObject.GetComponent<CanvasGroup>();
            ghostCanvasGroup.blocksRaycasts = false;
            ghostCanvasGroup.interactable = false;

            _dragGhostObject.transform.SetAsLastSibling();
            return true;
        }

        private static bool TryCreateLayer(
            string layerName,
            Sprite sprite,
            Color color,
            Material material,
            RectTransform parent,
            int siblingIndex)
        {
            if (parent == null || sprite == null)
            {
                return false;
            }

            GameObject layerObject = new GameObject($"TowerGhost{layerName}", typeof(RectTransform), typeof(Image));
            layerObject.layer = parent.gameObject.layer;

            RectTransform layerRect = layerObject.GetComponent<RectTransform>();
            layerRect.SetParent(parent, false);
            layerRect.anchorMin = Vector2.zero;
            layerRect.anchorMax = Vector2.one;
            layerRect.offsetMin = Vector2.zero;
            layerRect.offsetMax = Vector2.zero;
            layerRect.SetSiblingIndex(siblingIndex);

            Image layerImage = layerObject.GetComponent<Image>();
            layerImage.raycastTarget = false;
            layerImage.sprite = sprite;
            layerImage.color = color;
            layerImage.material = material;
            layerImage.preserveAspect = true;
            return true;
        }
    }
}