using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using Nancy.ViewEngines.Razor;
using Nancy.ViewEngines;
using Nancy.Localization;
using Nancy;

namespace CB.Common
{
    public class TemplateEngine
    {
        private readonly RazorViewEngine engine;
        //private volatile IRenderContext renderContext;//要么增加volatile，目前选择在代码段内设置
        private readonly IRazorConfiguration configuration;
        private readonly FileSystemViewLocationProvider fileSystemViewLocationProvider;
        private readonly IRootPathProvider rootPathProvider;
        private readonly ITextResource textResource;
        private readonly DiagnosticsViewResolver viewResolver;
        //private readonly System.Threading.ThreadLocal<IRenderContext> threadLocal;
        private readonly Func<IRenderContext> createContext;

        private TemplateEngine()
        {
            this.configuration = new CBRazorConfiguration();//new DefaultRazorConfiguration();
            this.textResource = new ResourceBasedTextResource(new DefaultAssemblyProvider());//new ResourceBasedTextResource(new ResourceAssemblyProvider());
            this.engine = new RazorViewEngine(this.configuration, this.textResource);//new RazorViewEngine(configuration);//

            this.rootPathProvider = new CPWapRootPathProvider();//new DefaultRootPathProvider();

            this.fileSystemViewLocationProvider = new FileSystemViewLocationProvider(this.rootPathProvider,
                new DefaultFileSystemReader());
            IViewCache cache = new WapViewCache();//DefaultViewCache();
            //this.viewCache = new DefaultViewCache();

            this.viewResolver = new DiagnosticsViewResolver(fileSystemViewLocationProvider);
            //this.renderContext =
            //    new DefaultRenderContextFactory(cache, viewResolver).GetRenderContext(new ViewLocationContext()
            //    {
            //        Context = new NancyContext()
            //    });

            createContext = () =>
            {
                return new DefaultRenderContextFactory(cache, viewResolver).GetRenderContext(new ViewLocationContext()
                {
                    Context = new NancyContext()
                });

                //return new DefaultRenderContext(viewResolver, cache, textResource, new ViewLocationContext()
                //{
                //    Context = new NancyContext()
                //});
            };
            //threadLocal = new System.Threading.ThreadLocal<IRenderContext>(createContext);
        }

        internal class CPWapRootPathProvider : IRootPathProvider
        {
            public string GetRootPath()
            {
                return Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "templates", "rzs");
            }
        }

        internal class DiagnosticsViewResolver : IViewResolver
        {
            private readonly FileSystemViewLocationProvider fileSystemViewLocationProvider;

            public DiagnosticsViewResolver(FileSystemViewLocationProvider fileSystemViewLocationProvider)
            {
                this.fileSystemViewLocationProvider = fileSystemViewLocationProvider;
            }
 
            public ViewLocationResult FindView(string viewName)
            {
                if (viewName.EndsWith("cshtml"))
                    viewName = viewName.Substring(0, viewName.Length - 7);
                if (viewName.EndsWith("shtml"))
                    viewName = viewName.Substring(0, viewName.Length - 6);
                var location =
                    this.fileSystemViewLocationProvider.GetLocatedViews(new[] {"cshtml", "vbhtml"})
                        .First(r => r.Name.ToLower() == viewName.ToLower());
                return location;
            }

            public ViewLocationResult GetViewLocation(string viewName, dynamic model,
                ViewLocationContext viewLocationContext)
            {
                return FindView(viewName);
            }
        }
        //for testing,can use web.config to config
        /// <summary>
        /// razor配置类
        /// </summary>
        /// <remarks>
        /// <razor disableAutoIncludeModelNamespace="false">
        /// <assemblies>
        /// <add assembly="System.Xml, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
        /// <add assembly="Nancy.Hosting.Aspnet" />
        /// </assemblies>
        /// <namespaces>
        /// <add namespace="System.Xml" />
        /// </namespaces>
        /// </razor>
        /// </remarks>
        [Obsolete("使用DefaultRazorConfiguration类，可以在config中进行配置")]
        public class CBRazorConfiguration : IRazorConfiguration
        {
            public bool AutoIncludeModelNamespace
            {
                get { return false; }
            }

            public IEnumerable<string> GetAssemblyNames()
            {
                return new string[] { "CB.Entity", "CB.Common", "CB.Wap", "CB.Data", "CB.Cache", "CB.Interface", "CB.Framework" };
            }

            public IEnumerable<string> GetDefaultNamespaces()
            {
                return new string[] { "CB.Entity", "CB.Common", "CB.Wap", "CB.Data", "CB.Cache", "CB.Interface", "CB.Framework" };
            }
        }

        private volatile static TemplateEngine _templateEngine;
        //static TemplateEngine()
        //{
        //    _templateEngine = new TemplateEngine();
        //}

        public static TemplateEngine Template
        {
            get
            {
                return new TemplateEngine();
                /*
                if (_templateEngine == null)
                {
                    _templateEngine = new TemplateEngine();
                    //System.Threading.Interlocked.CompareExchange<TemplateEngine>(ref _templateEngine, new TemplateEngine(), null);
                }
                return _templateEngine;//*/
            }
        }

        public Action<Stream> ExecuteTemplate(string viewName, object model, IDictionary<string, object> viewbag)
        {
            var renderContext = createContext();//threadLocal.Value;
            var hash = ((DynamicDictionary)renderContext.Context.ViewBag);
            hash.Clear();
            if (viewbag != null && viewbag.Count > 0)
            {
                foreach (var kv in viewbag)
                {
                    hash.Add(kv);
                }
            }
            var location = viewResolver.FindView(viewName);
            if (location == null)
                return null;
            var resp = this.engine.RenderView(location, model, renderContext);
            return resp.Contents;
        }

        public StringBuilder GetTemplateContent(string viewName, object model, IDictionary<string, object> viewbag)
        {
            var ms = new MemoryStream();
            var action = ExecuteTemplate(viewName, model, viewbag);
            
            if (action == null) return null;
            action.Invoke(ms);
            ms.Position = 0;
            var sb = new StringBuilder();
            using (var reader = new StreamReader(ms))
            {
                while (reader.Peek() > -1)
                {
                    sb.Append(reader.ReadLine());
                }
            }
            return sb;
        }

        //private static readonly object locker = new object();
        //private readonly System.Threading.SpinLock spinlock = new System.Threading.SpinLock();
        //public StringBuilder GetTemplateContent(string viewName, object model, IDictionary<string, object> viewbag)
        //{
        //    var t = System.Threading.Tasks.Task.Factory.StartNew(() =>
        //    {
        //        bool lockTaken = false;
        //        try
        //        {
                    
        //            spinlock.Enter(ref lockTaken);
        //        return GetTemplateContent1(viewName, model, viewbag);
        //        }
        //        finally
        //        {
        //            if (lockTaken) spinlock.Exit(false);
        //        }
        //    });
        //    System.Threading.Tasks.Task.WaitAny(new System.Threading.Tasks.Task[] { t }, 1000);
        //    return t.Result;
        //}
    }

    public class WapViewCache : IViewCache
    {
        private readonly System.Web.Caching.Cache webCache = System.Web.HttpRuntime.Cache;
        const string PrefixKey = "_Razor_Template_p_";
        readonly object objLocker = new object();

        public TCompiledView GetOrAdd<TCompiledView>(ViewLocationResult viewLocationResult, Func<ViewLocationResult, TCompiledView> valueFactory)
        {
            if (StaticConfiguration.DisableCaches)
            {
                return valueFactory(viewLocationResult);
            }
            var key = PrefixKey + viewLocationResult.Name;
            object o = webCache.Get(key);
            if (o == null)
            {
                //lock (objLocker)
                //{
                //    if (o == null)
                //    {

                //    }
                //}
                o = valueFactory(viewLocationResult);
                var nextSecondDay = DateTime.Now.AddDays(1);
                nextSecondDay = DateTime.Parse(nextSecondDay.ToString("yyyy-MM-dd") + " 01:00:00");
                webCache.Insert(key, o, null, System.DateTime.Now.AddHours(36), TimeSpan.Zero);
            }
            return (TCompiledView)o;
        }

        public void Remove(ViewLocationResult viewLocationResult)
        {
            if (StaticConfiguration.DisableCaches)
                return;

            var key = PrefixKey + viewLocationResult.Name;
            object o = webCache.Get(key);
            if (o != null)
                webCache.Remove(key);
            return;
        }
    }
}