using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Reflection;

namespace Sinvo.EplanHpD.Plugin
{
    public class AppDomainDllLoader
    {
        public static bool isLoaded = false;
        public static void SetLaoder()
        {
            if (isLoaded)
            {
                return;
            }
            // 接管DLL加载,解决依赖问题
            // 插件被加载时,AppContext.BaseDirectory 会指向Eplan的安装目录,导致一部分依赖的DLL在加载时找不到
            // 接管之后,从两个目录都查找一次
            //throw new NotImplementedException();
            try
            {
                // 防止重复加载 先卸载事件
                AppDomain.CurrentDomain.AssemblyResolve -= AssemblyResolveHandle;
            }
            catch (Exception ex)
            {
                Trace.TraceError(ex.Message);
            }

            AppDomain.CurrentDomain.AssemblyResolve += AssemblyResolveHandle;
            isLoaded = true;
        }

        public static Assembly AssemblyResolveHandle(object sender, ResolveEventArgs args)
        {
            var assemblyName = new AssemblyName(args.Name);

            // 判断是否已经被加载
            var loadedAssembly = AppDomain.CurrentDomain.GetAssemblies()
            .FirstOrDefault(a => a.FullName == assemblyName.FullName);
            if (loadedAssembly != null)
            {
                Debug.WriteLine($"DLL is loaded -> {loadedAssembly.FullName}");
                return loadedAssembly;
            }

            // 从当前路径下加载
            var path = Path.Combine(AppContext.BaseDirectory, $"{assemblyName.Name}.dll");
            if (File.Exists(path))
            {
                Debug.WriteLine($"Load dll for path -> {path}");

                return Assembly.LoadFile(path);
            }
            var envPath = System.Environment.CurrentDirectory;
            // 从插件路径中加载依赖
            path = Path.Combine(Path.GetDirectoryName(Assembly.GetAssembly(typeof(AppDomainDllLoader)).Location), $"{assemblyName.Name}.dll");
            if (File.Exists(path))
            {
                //MessageBox.Show($"Load dll for self path -> {path}");
                Debug.WriteLine($"Load dll for self path -> {path}");
                return Assembly.LoadFile(path);
            }
            //MessageBox.Show(path);
            Debug.WriteLine($"File not load! -> {path}");
            return null;
        }
    }
}