using System;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
using System.IO;
using Mesnac.PlugIn.View;

namespace Mesnac.Gui.PlugIn
{
    public class PlugInService
    {
        /// <summary>
        /// 扫描插件
        /// </summary>
        /// <param name="plugInPath">插件目录</param>
        /// <returns>返回插件列表</returns>
        public static List<PlugInDescriptor> ScanPlugIn(string plugInPath)
        {
            List<PlugInDescriptor> plugIns = new List<PlugInDescriptor>();      //保存插件列表

            DirectoryInfo dir = new DirectoryInfo(plugInPath);      //定义插件目录对象
            FileInfo[] plugInFiles = dir.GetFiles("*.dll", SearchOption.TopDirectoryOnly);        //扫描插件目录下的所有插件文件，只扫描顶层目录下的dll文件
            PlugInDescriptor plugIn = null;     //定义插件变量
            Assembly assembly = null;
            foreach (FileInfo fi in plugInFiles)
            {
                plugIn = new PlugInDescriptor();
                #region 解析插功能名称

                assembly = Assembly.LoadFile(fi.FullName);
                string functionName = String.Empty;         //dll对应功能名称
                IList<CustomAttributeData> lst = assembly.GetCustomAttributesData();
                foreach (CustomAttributeData data in lst)
                {
                    if (data.Constructor.DeclaringType.FullName == "System.Reflection.AssemblyDescriptionAttribute")
                    {
                        functionName = data.ConstructorArguments[0].Value as string;
                        break;
                    }
                }
                if (String.IsNullOrEmpty(functionName))
                {
                    foreach (CustomAttributeData data in lst)
                    {
                        if (data.Constructor.DeclaringType.FullName == "System.Reflection.AssemblyTitleAttribute")
                        {
                            functionName = data.ConstructorArguments[0].Value as string;
                            break;
                        }
                    }
                }
                plugIn.FunctionName = functionName;     //获取插件功能名称

                #endregion

                #region 解析视图窗口

                List<IViewContent> viewContents = new List<IViewContent>();
                Type[] types = assembly.GetTypes();
                foreach (Type t in types)
                {
                    Type[] result = t.FindInterfaces(IViewContentTypeFilter, null);
                    if (result != null && result.Length > 0)
                    {
                        IViewContent content = Activator.CreateInstance(t) as IViewContent;
                        viewContents.Add(content);
                    }
                }
                plugIn.ViewContents = viewContents;     //加载窗口集合

                #endregion

                plugIns.Add(plugIn);        //把插件添加到插件列表中
            }

            return plugIns;
        }
        /// <summary>
        /// 视图窗口接口过滤
        /// </summary>
        /// <param name="type"></param>
        /// <param name="target"></param>
        /// <returns></returns>
        public static bool IViewContentTypeFilter(Type type, object target)
        {
            if (type.FullName == "Mesnac.PlugIn.View.IViewContent")
            {
                return true;
            }
            return false;
        }
    }
}