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>();

        // ── 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;
        private const float PreviewTangent        = 44f;

        // 详细版：较大方块，标注 id / 类型 / 标题
        private const float DetailCellWidth  = 150f;
        private const float DetailCellHeight = 72f;
        private const float DetailStepX      = 210f;
        private const float DetailStepY      = 120f;

        // 简略版：很小的方块，仅标注 Block ID
        private const float SimpleCellWidth  = 62f;
        private const float SimpleCellHeight = 26f;
        private const float SimpleStepX      = 92f;
        private const float SimpleStepY      = 42f;

        /// <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，
        /// 支持负数与小数坐标，(0,0) 对应左侧中部。
        /// </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 cellW = simple ? SimpleCellWidth  : DetailCellWidth;
            float cellH = simple ? SimpleCellHeight : DetailCellHeight;
            float stepX = simple ? SimpleStepX      : DetailStepX;
            float stepY = simple ? SimpleStepY      : DetailStepY;

            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) 网格点 = 视口左侧中线（叠加平移量）
                float originX = PreviewPaddingLeft + _previewPan.x;
                float originY = area.height * 0.5f + _previewPan.y;

                // 计算各 block 矩形（左中对齐网格点，与运行时 pivot(0,0.5) 一致），按 blockId 索引
                Dictionary<string, Rect> cellRects = new Dictionary<string, Rect>();
                foreach (StoryBlockDefinition block in blocks)
                {
                    if (block == null || string.IsNullOrEmpty(block.blockId)) continue;

                    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, py - cellH * 0.5f, cellW, cellH);
                }

                // 先画连线：左右相连的流程图（起点右中 → 终点左中，水平切线）
                Handles.BeginGUI();
                foreach (StoryBlockDefinition block in blocks)
                {
                    if (block == null || !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);
                        Vector3 startTan = start + Vector3.right * PreviewTangent;
                        Vector3 endTan   = end   + Vector3.left  * PreviewTangent;

                        Handles.DrawBezier(start, end, startTan, endTan,
                            new Color(0.82f, 0.82f, 0.88f, 1f), null, simple ? 2f : 3f);
                    }
                }
                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 (block == null || !cellRects.TryGetValue(block.blockId, out Rect rect)) continue;

                    EditorGUI.DrawRect(rect, GetTypeColor(block.blockType));
                    string label = simple
                        ? block.blockId
                        : $"{block.blockId}\n[{block.blockType}]\n{block.GetDisplayTitle()}";
                    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），(0,0) 位于左侧中部，支持负数与小数。",
                MessageType.None);
        }

        /// <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>
        /// 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
    }
}