using System.Collections.Generic;
using Sirenix.OdinInspector;
using UnityEngine;
using Yarn.Unity;
#if UNITY_EDITOR
using UnityEditor;
using Sirenix.Utilities.Editor;
#endif

namespace Ichni.Story
{
    /// <summary>
    /// 单个章节的故事树数据，以 ScriptableObject 形式存储所有 block 定义与关联资产引用。
    /// 布局完全由每个 block 的 (gridColumn, gridRow) 静态决定，运行时全量展示。
    /// </summary>
    [CreateAssetMenu(fileName = "StoryData", menuName = "Ichni/Story/New/StoryData")]
    public class StoryData : SerializedScriptableObject
    {
        [LabelText("Chapter Index")]
        public string chapterIndex;

        [LabelText("Yarn Project")]
        [InfoBox("该章节对应的 YarnProject 编译资产，阶段 2 接线。")]
        public YarnProject yarnProject;

        [LabelText("Blocks")]
        [ListDrawerSettings(ShowFoldout = true, DefaultExpandedState = false, DraggableItems = true, ShowItemCount = true)]
        public List<StoryBlockDefinition> blocks = new List<StoryBlockDefinition>();

        /// <summary>
        /// 章节顶部 Timeline 的静态标记定义。
        /// 标记的横向位置始终由 <see cref="StoryTimelineMarkerDefinition.anchorBlockId"/> 指向的
        /// Block 的 <c>gridColumn</c> 推导，不在这里重复保存坐标，避免剧情树与 Timeline 脱节。
        /// </summary>
        [LabelText("Timeline Markers")]
        [ListDrawerSettings(ShowFoldout = true, DefaultExpandedState = false, DraggableItems = true, ShowItemCount = true)]
        [InfoBox("每个标记锚定到一个 TextBlock；运行时使用该 Block 的 Grid Column 对齐 Timeline。TextBlock 为 Current / Completed 时显示，Locked / Forbidden 时隐藏。未配置标记时，现有章节行为不变。")]
        public List<StoryTimelineMarkerDefinition> timelineMarkers = new List<StoryTimelineMarkerDefinition>();

        // ── Queries ─────────────────────────────────────────────────────────────

        /// <summary>
        /// 根据 blockId 获取 block 定义，未找到时返回 null。
        /// </summary>
        public StoryBlockDefinition GetBlock(string blockId)
        {
            foreach (StoryBlockDefinition block in blocks)
            {
                if (block.blockId == blockId)
                    return block;
            }

            return null;
        }

        /// <summary>
        /// 获取指定 blockId 的所有直接后继 block 定义。
        /// </summary>
        public IEnumerable<StoryBlockDefinition> GetNextBlocks(string blockId)
        {
            StoryBlockDefinition source = GetBlock(blockId);
            if (source == null) yield break;

            foreach (string nextId in source.nextBlockIds)
            {
                StoryBlockDefinition next = GetBlock(nextId);
                if (next != null)
                    yield return next;
            }
        }

        // ── Editor Preview ────────────────────────────────────────────────────────
#if UNITY_EDITOR
        private enum StoryPreviewMode { Detailed, Simple }

        // 编辑器 UI 临时状态（不参与序列化）
        [System.NonSerialized] private StoryPreviewMode _previewMode = StoryPreviewMode.Detailed;
        [System.NonSerialized] private Vector2 _previewPan;
        [System.NonSerialized] private bool _isPanningPreview;

        private const float PreviewViewportHeight = 380f;
        private const float PreviewPaddingLeft    = 24f;

        // 预览与运行时共用同一套“列 / 行代表 Block 中心点”的布局语义。
        // 这里的尺寸直接对应当前四种 Block Prefab 的设计尺寸；若未来修改 Prefab 尺寸，必须同步更新本组常量。
        private const float ImportantBlockWidth  = 600f;
        private const float ImportantBlockHeight = 375f;
        private const float SecondaryBlockWidth  = 400f;
        private const float SecondaryBlockHeight = 200f;
        private const float SongBlockWidth       = 400f;
        private const float SongBlockHeight      = 100f;
        private const float TutorialBlockWidth   = 400f;
        private const float TutorialBlockHeight  = 100f;

        // 与 StoryTreeController 默认 columnStep / rowStep 保持比例一致，
        // 因而预览中的相邻列、行间距也能反映运行时的实际布局关系。
        private const float RuntimeColumnStep = 720f;
        private const float RuntimeRowStep    = 525f;
        private const float DetailedPreviewScale = 0.25f;
        private const float SimplePreviewScale   = 0.10f;

        /// <summary>
        /// 在 Inspector 顶部绘制只读的故事树结构预览（流程图样式，连线左右相连）。
        /// 提供"详细 / 简略"两种可拖拽平移的视图；按 (gridColumn, gridRow) 摆放 block。
        /// 每个 Block 使用其运行时 Prefab 尺寸按统一比例缩放后的矩形，且列坐标始终代表 Block 的中心点，
        /// 从而让 Important / Secondary / Song / Tutorial 的体积与连线端点关系尽量接近游戏内画面。
        /// </summary>
        [PropertyOrder(-10)]
        [OnInspectorGUI]
        private void DrawStoryPreview()
        {
            SirenixEditorGUI.Title("Story Tree Preview", null, TextAlignment.Left, true);

            if (blocks == null || blocks.Count == 0)
            {
                EditorGUILayout.HelpBox("尚未定义任何 block。", MessageType.Info);
                return;
            }

            // 顶部工具条：模式切换 + 复位视图
            EditorGUILayout.BeginHorizontal();
            _previewMode = (StoryPreviewMode)GUILayout.Toolbar(
                (int)_previewMode, new[] { "Detailed", "Simple" }, GUILayout.Height(20f));
            if (GUILayout.Button("Reset View", GUILayout.Width(90f), GUILayout.Height(20f)))
                _previewPan = Vector2.zero;
            EditorGUILayout.EndHorizontal();

            bool simple = _previewMode == StoryPreviewMode.Simple;
            float previewScale = simple ? SimplePreviewScale : DetailedPreviewScale;
            float stepX = RuntimeColumnStep * previewScale;
            float stepY = RuntimeRowStep * previewScale;

            Rect area = GUILayoutUtility.GetRect(0f, PreviewViewportHeight, GUILayout.ExpandWidth(true));
            EditorGUI.DrawRect(area, new Color(0.12f, 0.12f, 0.14f, 1f));

            HandlePreviewPanning(area);

            // 裁剪到预览区，超出部分（平移后）不外溢到其它 Inspector 元素
            GUI.BeginClip(area);
            {
                // (0,0) 是 Block 的逻辑中心点。为避免第一列 Important Block 被左侧裁掉，
                // 初始视图预留半个最大 Block 宽度；这不改变 StoryData 的坐标语义。
                float originX = PreviewPaddingLeft + ImportantBlockWidth * previewScale * 0.5f + _previewPan.x;
                float originY = area.height * 0.5f + _previewPan.y;

                // 计算各 Block 的实际比例矩形。运行时同样以中心 Pivot 放置，因此 gridColumn / gridRow
                // 在预览中也对应矩形中心，而不是左边缘。
                Dictionary<string, Rect> cellRects = new Dictionary<string, Rect>();
                foreach (StoryBlockDefinition block in blocks)
                {
                    if (!HasPreviewableBlockId(block)) continue;

                    Vector2 blockSize = GetPreviewBlockSize(block, previewScale);
                    float px = originX + block.gridColumn * stepX; // 列向右为正（可负、可小数）
                    float py = originY + block.gridRow * stepY;    // 行向下为正、向上为负
                    cellRects[block.blockId] = new Rect(
                        px - blockSize.x * 0.5f,
                        py - blockSize.y * 0.5f,
                        blockSize.x,
                        blockSize.y);
                }

                // 先画连线：与 BlockConnectorView 相同，起点右中 → 以两个 Block 中心的中点列折线 → 终点左中。
                // 不使用端口中点作为转折列，避免不同宽度 Block 在同一列时出现不一致的转折位置。
                Handles.BeginGUI();
                foreach (StoryBlockDefinition block in blocks)
                {
                    if (!HasPreviewableBlockId(block) || !cellRects.TryGetValue(block.blockId, out Rect fromRect)) continue;

                    foreach (string nextId in block.nextBlockIds)
                    {
                        if (string.IsNullOrEmpty(nextId) || !cellRects.TryGetValue(nextId, out Rect toRect)) continue;

                        Vector3 start    = new Vector3(fromRect.xMax, fromRect.center.y, 0f);
                        Vector3 end      = new Vector3(toRect.xMin, toRect.center.y, 0f);
                        float midX = (fromRect.center.x + toRect.center.x) * 0.5f;
                        Vector3 mid1 = new Vector3(midX, start.y, 0f);
                        Vector3 mid2 = new Vector3(midX, end.y, 0f);

                        Handles.color = new Color(0.82f, 0.82f, 0.88f, 1f);
                        Handles.DrawAAPolyLine(simple ? 2f : 3f, start, mid1, mid2, end);
                    }
                }
                Handles.EndGUI();

                // 再画 block 方块
                GUIStyle labelStyle = new GUIStyle(EditorStyles.boldLabel)
                {
                    alignment = TextAnchor.MiddleCenter,
                    wordWrap  = true,
                    richText  = false,
                    fontSize  = simple ? 9 : 11,
                    normal    = { textColor = Color.white }
                };

                foreach (StoryBlockDefinition block in blocks)
                {
                    if (!HasPreviewableBlockId(block) || !cellRects.TryGetValue(block.blockId, out Rect rect)) continue;

                    EditorGUI.DrawRect(rect, GetTypeColor(block.blockType));
                    string label = GetPreviewLabel(block, simple, rect.height);
                    GUI.Label(rect, label, labelStyle);
                }
            }
            GUI.EndClip();

            EditorGUILayout.HelpBox(
                "在预览区内拖拽可平移视图。列 = 水平（右为正），行 = 垂直（下为正、上为负）；坐标代表 Block 中心点。预览按当前 Prefab 尺寸比例绘制：Important 600×375、Secondary 400×200、Song / Tutorial 400×100。",
                MessageType.None);
        }

        /// <summary>
        /// 返回一个 Block 在 Inspector 预览中的尺寸。所有类型使用同一缩放比例，
        /// 因而宽高比及不同 Block 之间的体积关系与运行时 Prefab 保持一致。
        /// </summary>
        private static Vector2 GetPreviewBlockSize(StoryBlockDefinition block, float previewScale)
        {
            Vector2 runtimeSize = block.blockType switch
            {
                StoryBlockType.Text when block.textImportance == TextBlockImportance.Important =>
                    new Vector2(ImportantBlockWidth, ImportantBlockHeight),
                StoryBlockType.Text => new Vector2(SecondaryBlockWidth, SecondaryBlockHeight),
                StoryBlockType.Song => new Vector2(SongBlockWidth, SongBlockHeight),
                StoryBlockType.Tutorial => new Vector2(TutorialBlockWidth, TutorialBlockHeight),
                _ => Vector2.zero
            };

            return runtimeSize * previewScale;
        }

        /// <summary>
        /// 根据可用高度选择预览标签密度。Song / Tutorial 的真实比例高度较小，
        /// 因此只显示 Block ID，避免文字撑破矩形而掩盖实际体积关系。
        /// </summary>
        private static string GetPreviewLabel(StoryBlockDefinition block, bool simple, float blockHeight)
        {
            if (simple || blockHeight < 32f)
            {
                return block.blockId;
            }

            if (blockHeight < 60f)
            {
                return $"{block.blockId}\n[{block.blockType}]";
            }

            return $"{block.blockId}\n[{block.blockType}]\n{block.GetDisplayTitle()}";
        }

        /// <summary>
        /// 处理预览区内的鼠标拖拽平移。
        /// </summary>
        private void HandlePreviewPanning(Rect area)
        {
            Event e = Event.current;
            switch (e.type)
            {
                case EventType.MouseDown:
                    if (area.Contains(e.mousePosition))
                    {
                        _isPanningPreview = true;
                        e.Use();
                    }
                    break;
                case EventType.MouseDrag:
                    if (_isPanningPreview)
                    {
                        _previewPan += e.delta;
                        GUI.changed = true;
                        e.Use();
                    }
                    break;
                case EventType.MouseUp:
                    if (_isPanningPreview)
                    {
                        _isPanningPreview = false;
                        e.Use();
                    }
                    break;
            }
        }

        /// <summary>
        /// 判断 Block 能否参与 Inspector 中的故事树预览。
        /// 新增 Block 时，Odin 会先创建一个尚未填写 blockId 的临时数据项；它还不能作为
        /// Dictionary 的 Key，也不应在预览中显示或连接。统一在三个预览阶段过滤，避免后续
        /// Draw / TryGetValue 阶段再次把空引用传入 Dictionary。
        /// </summary>
        private static bool HasPreviewableBlockId(StoryBlockDefinition block)
        {
            return block != null && !string.IsNullOrWhiteSpace(block.blockId);
        }

        /// <summary>
        /// 预览中不同 block 类型的填充色。
        /// </summary>
        private static Color GetTypeColor(StoryBlockType type)
        {
            return type switch
            {
                StoryBlockType.Text     => new Color(0.20f, 0.42f, 0.72f, 1f), // 蓝
                StoryBlockType.Song     => new Color(0.62f, 0.30f, 0.66f, 1f), // 紫
                StoryBlockType.Tutorial => new Color(0.28f, 0.56f, 0.36f, 1f), // 绿
                _                       => new Color(0.4f, 0.4f, 0.4f, 1f)
            };
        }
#endif
    }
}