// ─────────────────────────────────────────────────────────────────────────────
//  WLIslandUi.cs — 던전 입구의 이름표·「들어가기」 버튼 · 더미 머티리얼
//
//  발주서 WL-816d §1-② 「플레이어가 가까이 가면 『들어가기』가 뜨게 하라」
//  🔴 기존 UI 프리팹·Canvas 를 고치지 않는다 — 필요한 것만 런타임에 만들고, 떠날 때 지운다.
//  🔴 배경/캐릭터 머티리얼은 읽지도 고치지도 않는다(816a 소유). 더미용 머티리얼만 새로 만든다.
// ─────────────────────────────────────────────────────────────────────────────

using System.Collections.Generic;
using TMPro;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

namespace WL.Island
{
    /// <summary>더미 전용 머티리얼 공장(기존 머티리얼은 건드리지 않는다).</summary>
    public static class WLIslandLook
    {
        static readonly Dictionary<int, Material> s_cache = new Dictionary<int, Material>(8);
        static Shader s_shader;

        public static Shader LitShader
        {
            get
            {
                if (s_shader != null) return s_shader;
                s_shader = Shader.Find("Universal Render Pipeline/Lit");
                if (s_shader == null) s_shader = Shader.Find("Universal Render Pipeline/Simple Lit");
                if (s_shader == null) s_shader = Shader.Find("Sprites/Default");
                return s_shader;
            }
        }

        public static Material GateMaterial(Color c)
        {
            int key = ((Color32)c).GetHashCode();
            Material m;
            if (s_cache.TryGetValue(key, out m) && m != null) return m;
            if (LitShader == null) return null;

            m = new Material(LitShader) { name = "WL_GateDummy", hideFlags = HideFlags.DontSave };
            if (m.HasProperty("_BaseColor")) m.SetColor("_BaseColor", c);
            if (m.HasProperty("_Color")) m.SetColor("_Color", c);
            if (m.HasProperty("_Smoothness")) m.SetFloat("_Smoothness", 0.15f);
            s_cache[key] = m;
            return m;
        }
    }

    /// <summary>입구 위에 뜨는 3D 이름표.</summary>
    public static class WLIslandLabel
    {
        public static void Attach(Transform parent, Vector3 localPos, string text)
        {
            var go = new GameObject("label");
            go.transform.SetParent(parent, false);
            go.transform.localPosition = localPos;

            var tmp = go.AddComponent<TextMeshPro>();
            tmp.text = text;
            tmp.fontSize = 3.2f;
            tmp.alignment = TextAlignmentOptions.Center;
            tmp.color = Color.white;
            var rt = tmp.GetComponent<RectTransform>();
            if (rt != null) rt.sizeDelta = new Vector2(6f, 1.4f);

            go.AddComponent<WLIslandBillboard>();
        }
    }

    /// <summary>이름표가 항상 카메라를 본다.</summary>
    public sealed class WLIslandBillboard : MonoBehaviour
    {
        void LateUpdate()
        {
            var cam = Camera.main;
            if (cam == null) return;
            transform.rotation = Quaternion.LookRotation(transform.position - cam.transform.position, Vector3.up);
        }
    }

    /// <summary>화면 아래 「들어가기」 — 런타임 생성 Canvas 1개(기존 UI 무변경).</summary>
    public static class WLIslandPrompt
    {
        static GameObject s_root;
        static TextMeshProUGUI s_text;
        static WLDungeonGate s_target;

        public static bool Visible { get { return s_root != null && s_root.activeSelf; } }
        public static string LastText = "";

        public static void Show(WLIslandSettings cfg, string text, WLDungeonGate gate)
        {
            Ensure(cfg);
            s_target = gate;
            LastText = text;
            if (s_text != null) s_text.text = text;
            if (s_root != null) s_root.SetActive(true);
        }

        public static void Hide()
        {
            s_target = null;
            if (s_root != null) s_root.SetActive(false);
        }

        static void Ensure(WLIslandSettings cfg)
        {
            if (s_root != null) return;

            s_root = new GameObject("~WL_IslandPrompt");
            Object.DontDestroyOnLoad(s_root);

            var canvas = s_root.AddComponent<Canvas>();
            canvas.renderMode = RenderMode.ScreenSpaceOverlay;
            canvas.sortingOrder = 9000;
            var scaler = s_root.AddComponent<CanvasScaler>();
            scaler.uiScaleMode = CanvasScaler.ScaleMode.ScaleWithScreenSize;
            scaler.referenceResolution = new Vector2(1080f, 1920f);
            scaler.matchWidthOrHeight = 0.5f;
            s_root.AddComponent<GraphicRaycaster>();

            if (Object.FindFirstObjectByType<EventSystem>() == null)
            {
                var es = new GameObject("~WL_EventSystem");
                Object.DontDestroyOnLoad(es);
                es.AddComponent<EventSystem>();
                es.AddComponent<StandaloneInputModule>();
            }

            // 버튼
            var btnGo = new GameObject("btn_enter", typeof(RectTransform));
            btnGo.transform.SetParent(s_root.transform, false);
            var brt = btnGo.GetComponent<RectTransform>();
            brt.anchorMin = new Vector2(0.5f, 0f);
            brt.anchorMax = new Vector2(0.5f, 0f);
            brt.pivot = new Vector2(0.5f, 0f);
            brt.anchoredPosition = new Vector2(0f, 260f);
            brt.sizeDelta = new Vector2(520f, 150f);

            var img = btnGo.AddComponent<Image>();
            img.color = new Color(0.13f, 0.09f, 0.20f, 0.92f);
            var btn = btnGo.AddComponent<Button>();
            btn.targetGraphic = img;
            btn.onClick.AddListener(OnClick);

            var txtGo = new GameObject("text", typeof(RectTransform));
            txtGo.transform.SetParent(btnGo.transform, false);
            var trt = txtGo.GetComponent<RectTransform>();
            trt.anchorMin = Vector2.zero; trt.anchorMax = Vector2.one;
            trt.offsetMin = Vector2.zero; trt.offsetMax = Vector2.zero;

            s_text = txtGo.AddComponent<TextMeshProUGUI>();
            s_text.fontSize = 44f;
            s_text.alignment = TextAlignmentOptions.Center;
            s_text.color = Color.white;
            s_text.text = cfg != null ? cfg.enterButtonText : "들어가기";

            s_root.SetActive(false);
        }

        static void OnClick()
        {
            var g = s_target;
            if (g != null) g.Enter();
        }
    }
}