using System;
using System.IO;
using System.Linq;
using System.Reflection;
using Autodesk.Revit;
using Autodesk.Revit.DB;

namespace RevitLess
{
    /// <summary>
    ///     Revit环境
    /// </summary>
    internal class RevitContext
    {
        /// <summary>
        ///     使用此构造方法前需要调用 RevitContext.AddEnv();
        /// </summary>
        static RevitContext()
        {
            OnAssemblyResolve();
        }

        public event EventHandler<Product> InitFinished;

        //用于判断当前类的实例是否存在
        private static readonly object lockobj = new();

        private static RevitContext _instance;

        /// <summary>
        ///     revit程序目录
        /// </summary>
        public static string RevitAppPath;
        // 此路径为动态反射搜索路径 、 此路径可为任意路径（只要路径下有RevitNET 所需依赖项即可，完整依赖项可在 Naviswork 2016 下面找到）

        private Product revitProduct;

        /// <summary>
        ///     Revit应用程序实例
        /// </summary>
        public Autodesk.Revit.ApplicationServices.Application Application => revitProduct?.Application;

        /// <summary>
        ///     自身静态类，单例，内存中只有一份
        /// </summary>
        public static RevitContext Instance
        {
            get
            {
                if (_instance == null)
                {
                    lock (lockobj)
                    {
                        _instance ??= new RevitContext();
                    }
                }

                return _instance;
            }
        }

        /// <summary>
        ///     打开REVIT文件时的设置
        /// </summary>
        public OpenOptions OpenOptions { get; set; }

        public void Exit()
        {
            revitProduct?.Exit();
        }

        public void InitRevitAppAndOpenFile()
        {
            InitFinished?.Invoke(this, revitProduct);
        }

        /// <summary>
        ///     添加revit安装路径到环境变量以便加载相应的DLL
        /// </summary>
        /// <param name="revitPath">添加revit安装路径</param>
        public static void OnAssemblyResolve(string revitPath = null)
        {
            if (revitPath != null)
            {
                RevitAppPath = revitPath;
            }

            AddEnvironmentPaths(RevitAppPath);
            AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;
        }

        /// <summary>
        ///     打开文件
        /// </summary>
        /// <param name="filename"></param>
        /// <returns></returns>
        public Document OpenFile(string filename)
        {
            if (File.Exists(filename))
            {
                ModelPath model = new FilePath(filename);
                return revitProduct.Application.OpenDocumentFile(model, OpenOptions);
            }

            throw new FileNotFoundException($"{filename}不存在。");
        }

        public void Run()
        {
            OpenOptions = new OpenOptions
            {
                Audit = true,
                AllowOpeningLocalByWrongUser = false,
                DetachFromCentralOption = DetachFromCentralOption.DetachAndDiscardWorksets //从中心模型分离
            };
            revitProduct = Product.GetInstalledProduct();
            var clientApplicationId = new ClientApplicationId(Guid.NewGuid(), "RevitContext", "BIM");
            revitProduct.SetPreferredLanguage(Autodesk.Revit.ApplicationServices.LanguageType.Chinese_Simplified);
            revitProduct.Initialize_ForAutodeskInternalUseOnly(clientApplicationId, "I am authorized by Autodesk to use this UI-less functionality.");
        }

        /// <summary>
        ///     添加环境变量
        /// </summary>
        /// <param name="paths">revit安装路径</param>
        private static void AddEnvironmentPaths(params string[] paths)
        {
            string[] first =
            {
                Environment.GetEnvironmentVariable("PATH") ?? string.Empty
            };
            var value = string.Join(Path.PathSeparator.ToString(), first.Concat(paths));
            Environment.SetEnvironmentVariable("PATH", value);
        }

        /// <summary>
        ///     动态加载revit相关的dll
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="args"></param>
        /// <returns></returns>
        private static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
        {
            var assemblyName = new AssemblyName(args.Name);
            var text = $"{Path.Combine(RevitAppPath, assemblyName.Name)}.dll";
            ////$字符将{0}占位直接用对象相关字段替换
            //var file = string.Format("{0}.dll", System.IO.Path.Combine(item, assemblyName.Name));

            if (File.Exists(text))
            {
                //Console.WriteLine($"加载Revit Dll路径:{text}");
                return Assembly.LoadFrom(text);
            }

            return args.RequestingAssembly;
        }
    }
}