using UnityEngine;

namespace OctoberStudio.Rendering
{
    /// <summary>
    /// 渲染器模式：Sprite (2D) 或 Mesh (3D)
    /// </summary>
    public enum RendererMode
    {
        Sprite = 0,
        Mesh = 1,
    }

    /// <summary>
    /// 统一渲染适配器。
    /// 让 OctoberStudio 的业务逻辑无需关心使用 <see cref="SpriteRenderer"/> 还是 <see cref="MeshRenderer"/>。
    /// 在 Prefab 上挂载此组件，选择 Mode，勾选 Auto Fetch 即可让组件自动绑定子级 Renderer。
    ///
    /// 典型用法：
    ///   2D Prefab → Mode=Sprite，自动找 SpriteRenderer，行为与原版完全一致
    ///   3D Prefab → Mode=Mesh，自动找 MeshRenderer，所有 Color/Flip/Sorting 操作映射到 Mesh 上
    ///
    /// 业务代码统一通过适配器属性 (Color/FlipX/SortingOrder/...) 操作，
    /// 切换 2D/3D 时无需重写逻辑层。
    /// </summary>
    [DisallowMultipleComponent]
    [ExecuteAlways]
    [AddComponentMenu("OctoberStudio/Rendering/Renderer Adapter")]
    public class RendererAdapter : MonoBehaviour
    {
        [Tooltip("渲染模式：Sprite=2D 模式 (默认), Mesh=3D 模式")]
        [SerializeField] private RendererMode mode = RendererMode.Sprite;

        [Tooltip("启用后会在 OnValidate / Reset 自动查找并绑定子级 Renderer 组件")]
        [SerializeField] private bool autoFetch = true;

        [Tooltip("自动查找时的搜索根 (留空 = 自己)")]
        [SerializeField] private Transform fetchRoot;

        [Tooltip("是否在 mode 切换时自动启用/禁用对应的 Renderer (推荐勾选避免两个同时显示)")]
        [SerializeField] private bool applyEnabledOnModeChange = true;

        [Header("Bound Renderers (可手动指定，否则自动 fetch)")]
        [SerializeField] private SpriteRenderer spriteRenderer;
        [SerializeField] private MeshRenderer meshRenderer;

        #region Public Read-only

        public RendererMode Mode => mode;
        public bool IsSpriteMode => mode == RendererMode.Sprite;
        public bool IsMeshMode => mode == RendererMode.Mesh;
        public SpriteRenderer Sprite => spriteRenderer;
        public MeshRenderer Mesh => meshRenderer;

        /// <summary>
        /// 当前激活的 Renderer (Sprite 模式返回 SpriteRenderer，Mesh 模式返回 MeshRenderer)
        /// </summary>
        public Renderer Active => mode == RendererMode.Sprite ? (Renderer)spriteRenderer : meshRenderer;

        #endregion

        #region Unified API

        public bool IsVisible => Active != null && Active.isVisible;

        public Bounds Bounds => Active != null
            ? Active.bounds
            : new Bounds(transform.position, Vector3.zero);

        public bool Enabled
        {
            get => Active != null && Active.enabled;
            set { if (Active != null) Active.enabled = value; }
        }

        public Color Color
        {
            get
            {
                if (mode == RendererMode.Sprite) return spriteRenderer != null ? spriteRenderer.color : Color.white;
                return meshRenderer != null && meshRenderer.sharedMaterial != null && meshRenderer.sharedMaterial.HasProperty(MainColorPropID)
                    ? meshRenderer.material.GetColor(MainColorPropID)
                    : Color.white;
            }
            set
            {
                if (mode == RendererMode.Sprite)
                {
                    if (spriteRenderer != null) spriteRenderer.color = value;
                }
                else
                {
                    if (meshRenderer != null && meshRenderer.material != null && meshRenderer.material.HasProperty(MainColorPropID))
                        meshRenderer.material.SetColor(MainColorPropID, value);
                }
            }
        }

        public float Alpha
        {
            get => Color.a;
            set { var c = Color; c.a = value; Color = c; }
        }

        /// <summary>
        /// 水平翻转。
        /// Sprite 模式：spriteRenderer.flipX
        /// Mesh 模式：transform.localScale.x 符号
        /// </summary>
        public bool FlipX
        {
            get
            {
                if (mode == RendererMode.Sprite) return spriteRenderer != null && spriteRenderer.flipX;
                return transform.localScale.x < 0;
            }
            set
            {
                if (mode == RendererMode.Sprite)
                {
                    if (spriteRenderer != null) spriteRenderer.flipX = value;
                }
                else
                {
                    var s = transform.localScale;
                    s.x = Mathf.Abs(s.x) * (value ? -1f : 1f);
                    transform.localScale = s;
                }
            }
        }

        public bool FlipY
        {
            get
            {
                if (mode == RendererMode.Sprite) return spriteRenderer != null && spriteRenderer.flipY;
                return transform.localScale.y < 0;
            }
            set
            {
                if (mode == RendererMode.Sprite)
                {
                    if (spriteRenderer != null) spriteRenderer.flipY = value;
                }
                else
                {
                    var s = transform.localScale;
                    s.y = Mathf.Abs(s.y) * (value ? -1f : 1f);
                    transform.localScale = s;
                }
            }
        }

        public int SortingOrder
        {
            get => Active != null ? Active.sortingOrder : 0;
            set { if (Active != null) Active.sortingOrder = value; }
        }

        public string SortingLayerName
        {
            get => Active != null ? Active.sortingLayerName : "Default";
            set { if (Active != null) Active.sortingLayerName = value; }
        }

        public int SortingLayerID
        {
            get => Active != null ? Active.sortingLayerID : 0;
            set { if (Active != null) Active.sortingLayerID = value; }
        }

        public Material Material
        {
            get => Active != null ? Active.material : null;
            set { if (Active != null) Active.material = value; }
        }

        public Material SharedMaterial
        {
            get => Active != null ? Active.sharedMaterial : null;
            set { if (Active != null) Active.sharedMaterial = value; }
        }

        #endregion

        #region Lifecycle

        private static readonly int MainColorPropID = Shader.PropertyToID("_Color");

        private void Reset()
        {
            FetchComponents();
            ApplyMode();
        }

        private void OnValidate()
        {
            if (autoFetch) FetchComponents();
            if (applyEnabledOnModeChange) ApplyMode();
        }

        private void Awake()
        {
            if (autoFetch) FetchComponents();
            if (applyEnabledOnModeChange) ApplyMode();
        }

        #endregion

        #region Public Operations

        /// <summary>
        /// 在子级中查找并绑定对应类型的 Renderer (优先用根节点上的，再退到子级)。
        /// </summary>
        [ContextMenu("Fetch Renderer Components")]
        public void FetchComponents()
        {
            var root = fetchRoot != null ? fetchRoot : transform;
            if (spriteRenderer == null)
            {
                spriteRenderer = root.GetComponent<SpriteRenderer>();
                if (spriteRenderer == null) spriteRenderer = root.GetComponentInChildren<SpriteRenderer>(true);
            }
            if (meshRenderer == null)
            {
                meshRenderer = root.GetComponent<MeshRenderer>();
                if (meshRenderer == null) meshRenderer = root.GetComponentInChildren<MeshRenderer>(true);
            }
        }

        /// <summary>
        /// 根据当前 mode 启用/禁用对应 Renderer (避免两个同时显示)。
        /// </summary>
        [ContextMenu("Apply Mode")]
        public void ApplyMode()
        {
            if (spriteRenderer != null) spriteRenderer.enabled = (mode == RendererMode.Sprite);
            if (meshRenderer != null) meshRenderer.enabled = (mode == RendererMode.Mesh);
        }

        /// <summary>
        /// 运行时切换 mode (推荐通过这个方法切换，避免直接改 Inspector 字段不生效)。
        /// </summary>
        public void SetMode(RendererMode newMode)
        {
            if (mode == newMode) return;
            mode = newMode;
            if (applyEnabledOnModeChange) ApplyMode();
        }

        #endregion
    }
}