using System;
using System.Collections.Generic;
using Autodesk.AutoCAD.DatabaseServices;
using CadParamPluging.Common;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.EditorInput;

namespace CadParamPluging.Cad
{
    /// <summary>
    /// 辅助类：用于操作 AutoCAD 的扩展字典 (Extension Dictionary / NOD)
    /// </summary>
    public static class DictionaryHelper
    {
        // 我们在 NOD (Named Objects Dictionary) 中使用的根字典名称
        private const string AppDictionaryName = "CadParamPluging_Data";
        // 存储参数的 XRecord 名称
        private const string ParamsRecordName = "DrawingParams";

        /// <summary>
        /// 将参数包保存到当前文档的 Extension Dictionary (NOD) 中
        /// </summary>
        public static void SaveParams(Database db, ParamBag bag)
        {
            if (db == null || bag == null || bag.Items == null || bag.Items.Count == 0)
            {
                return;
            }

            using (var tr = db.TransactionManager.StartTransaction())
            {
                var nod = (DBDictionary)tr.GetObject(db.NamedObjectsDictionaryId, OpenMode.ForWrite);

                // 1. 获取或创建我们的应用专属字典
                DBDictionary appDict;
                if (nod.Contains(AppDictionaryName))
                {
                    appDict = (DBDictionary)tr.GetObject(nod.GetAt(AppDictionaryName), OpenMode.ForWrite);
                }
                else
                {
                    appDict = new DBDictionary();
                    nod.SetAt(AppDictionaryName, appDict);
                    tr.AddNewlyCreatedDBObject(appDict, true);
                }

                // 2. 准备数据 (XRecord)
                // XRecord 本质上是一个 ResultBuffer 链表
                // 我们使用 DxfCode.Text (1000) 来存储 key=value 字符串
                var rb = new ResultBuffer();
                // serialize user inputs into a single text block
                var fullString = "";
                foreach (var item in bag.Items)
                {
                    if (!string.IsNullOrWhiteSpace(item.Key))
                    {
                        fullString += $"{item.Key}={item.Value ?? string.Empty}\n";
                    }
                }

                // DxfCode.Text has a 255-character limit in AutoCAD ResultBuffer.
                // We use code 301 (XTextString) and chunk the string to support any length.
                var temp = fullString;
                while (temp.Length > 0)
                {
                    var chunk = temp.Length > 250 ? temp.Substring(0, 250) : temp;
                    rb.Add(new TypedValue(301, chunk)); // 301 = DxfCode.XTextString
                    temp = temp.Length > 250 ? temp.Substring(250) : "";
                }
                
                try 
                {
                    // Application.DocumentManager.MdiActiveDocument.Editor.WriteMessage($"\n[CadParamPluging] Saving Params: Count={bag.Items.Count}\n");
                }
                catch {}

                var xrec = new Xrecord();
                xrec.Data = rb;

                // 如果已存在则覆盖，否则添加
                if (appDict.Contains(ParamsRecordName))
                {
                    // 为了简单起见，这里选择直接删除旧的再添加新的，或者覆盖
                    // 如果用 GetObject 获取旧的 xrec，可以直接 xrec.Data = rb
                    var oldId = appDict.GetAt(ParamsRecordName);
                    var oldXrec = (Xrecord)tr.GetObject(oldId, OpenMode.ForWrite);
                    oldXrec.Data = rb;
                }
                else
                {
                    appDict.SetAt(ParamsRecordName, xrec);
                    tr.AddNewlyCreatedDBObject(xrec, true);
                }

                tr.Commit();
            }
        }

        /// <summary>
        /// (可选) 从当前文档读取参数
        /// </summary>
        public static ParamBag ReadParams(Database db)
        {
            var bag = new ParamBag();
            using (var tr = db.TransactionManager.StartTransaction())
            {
                var nod = (DBDictionary)tr.GetObject(db.NamedObjectsDictionaryId, OpenMode.ForRead);
                if (!nod.Contains(AppDictionaryName))
                {
                    return bag;
                }

                var appDict = (DBDictionary)tr.GetObject(nod.GetAt(AppDictionaryName), OpenMode.ForRead);
                if (!appDict.Contains(ParamsRecordName))
                {
                    return bag;
                }

                var xrec = (Xrecord)tr.GetObject(appDict.GetAt(ParamsRecordName), OpenMode.ForRead);
                var rb = xrec.Data;
                if (rb == null)
                {
                    return bag;
                }

                var sb = new System.Text.StringBuilder();
                bool hasCode301 = false;
                
                // Read chunks from new format
                foreach (var tv in rb)
                {
                    if (tv.TypeCode == 301)
                    {
                        hasCode301 = true;
                        if (tv.Value is string s)
                        {
                            sb.Append(s);
                        }
                    }
                }

                if (hasCode301)
                {
                    var fullText = sb.ToString();
                    foreach (var line in fullText.Split(new[] { '\n' }, StringSplitOptions.RemoveEmptyEntries))
                    {
                        var parts = line.Split(new[] { '=' }, 2);
                        if (parts.Length == 2) bag.Set(parts[0], parts[1]);
                        else if (parts.Length == 1) bag.Set(parts[0], "");
                    }
                    return bag;
                }

                // Fallback to read from old Code 1 format
                foreach (var tv in rb)
                {
                    if (tv.TypeCode == (int)DxfCode.Text)
                    {
                        var line = tv.Value as string;
                        if (!string.IsNullOrWhiteSpace(line))
                        {
                            var parts = line.Split(new[] { '=' }, 2);
                            if (parts.Length == 2)
                            {
                                bag.Set(parts[0], parts[1]);
                                
                                try
                                {
                                     // Log Hardness read
                                }
                                catch {}
                            }
                            else if (parts.Length == 1)
                            {
                                bag.Set(parts[0], "");
                            }
                        }
                    }
                }
            }
            return bag;
        }
    }
}