using System;

using System.Collections.Generic;

using System.Linq;

using System.Web.Configuration;

using System.Configuration.Provider;

using System.Web;

using System.Configuration;

using ClientDependency.Core.FileRegistration.Providers;

using ClientDependency.Core.CompositeFiles.Providers;

using ClientDependency.Core.Logging;

using System.IO;



namespace ClientDependency.Core.Config

{

    public class ClientDependencySettings

    {

        /// <summary>

        /// used for singleton

        /// </summary>

        private static ClientDependencySettings _settings;

        private static readonly object Lock = new object();



        /// <summary>

        /// Default constructor, for use with a web context app

        /// </summary>

        internal ClientDependencySettings()

        {

            if (HttpContext.Current == null)

            {

                throw new InvalidOperationException(

                    "HttpContext.Current must exist when using the empty constructor for ClientDependencySettings, otherwise use the alternative constructor");

            }



            LoadProviders((ClientDependencySection)ConfigurationManager.GetSection("clientDependency"), new HttpContextWrapper(HttpContext.Current));

            

        }



        internal ClientDependencySettings(FileInfo configFile, HttpContextBase ctx)

        {

            var fileMap = new ExeConfigurationFileMap { ExeConfigFilename = configFile.FullName };

            var configuration = ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);

            LoadProviders((ClientDependencySection)configuration.GetSection("clientDependency"), ctx);            

        }



        /// <summary>

        /// Singleton, used for web apps

        /// </summary>

        public static ClientDependencySettings Instance

        {

            get

            {

                if (_settings == null)

                {

                    lock(Lock)

                    {

                        //double check

                        if (_settings == null)

                        {

                            _settings = new ClientDependencySettings();

                        }

                    }

                }

                return _settings;

            }

        }



        /// <summary>

        /// The file extensions of Client Dependencies that are file based as opposed to request based.

        /// Any file that doesn't have the extensions listed here will be request based, request based is

        /// more overhead for the server to process.

        /// </summary>

        /// <example>

        /// A request based JavaScript file may be  a .ashx that dynamically creates JavaScript server side.

        /// </example>

        /// <remarks>

        /// If this is not explicitly set, then the extensions 'js' and 'css' are the defaults.

        /// </remarks>

        public List<string> FileBasedDependencyExtensionList { get; set; }

        

        public int Version { get; set; }



        public ILogger Logger { get; private set; }



        /// <summary>

        /// Returns the default MVC renderer

        /// </summary>

        public BaseRenderer DefaultMvcRenderer { get; private set; }



        /// <summary>

        /// Returns the MVC renderer provider collection

        /// </summary>

        public RendererCollection MvcRendererCollection { get; private set; }



        /// <summary>

        /// Returns the default file registration provider

        /// </summary>

        public WebFormsFileRegistrationProvider DefaultFileRegistrationProvider { get; private set; }



        /// <summary>

        /// Returns the file registration provider collection

        /// </summary>

        public FileRegistrationProviderCollection FileRegistrationProviderCollection { get; private set; }



        /// <summary>

        /// Returns the default composite file processing provider

        /// </summary>

        public BaseCompositeFileProcessingProvider DefaultCompositeFileProcessingProvider { get; private set; }



        /// <summary>

        /// Returns the composite file processing provider collection

        /// </summary>

        public CompositeFileProcessingProviderCollection CompositeFileProcessingProviderCollection { get; private set; }



        /// <summary>

        /// Returns the default file map provider

        /// </summary>

        public BaseFileMapProvider DefaultFileMapProvider { get; private set; }



        /// <summary>

        /// Returns the collection of file map providers

        /// </summary>

        public FileMapProviderCollection FileMapProviderCollection { get; private set; }



        public ClientDependencySection ConfigSection { get; private set; }

       

        public string CompositeFileHandlerPath { get; set; }

       

        internal void LoadProviders(ClientDependencySection section, HttpContextBase http)

        {

         

            ConfigSection = section;



            FileRegistrationProviderCollection = new FileRegistrationProviderCollection();

            CompositeFileProcessingProviderCollection = new CompositeFileProcessingProviderCollection();

            MvcRendererCollection = new RendererCollection();

            FileMapProviderCollection = new FileMapProviderCollection();



            // if there is no section found, then create one

            if (ConfigSection == null)

            {

                //create a new section with the default settings

                ConfigSection = new ClientDependencySection();                            

            }



            //need to check if it's an http path or a lambda path

            var path = ConfigSection.CompositeFileElement.CompositeFileHandlerPath;

            CompositeFileHandlerPath = path.StartsWith("~/")

                ? VirtualPathUtility.ToAbsolute(ConfigSection.CompositeFileElement.CompositeFileHandlerPath, http.Request.ApplicationPath)

                : ConfigSection.CompositeFileElement.CompositeFileHandlerPath;

            Version = ConfigSection.Version;

            FileBasedDependencyExtensionList = ConfigSection.FileBasedDependencyExtensionList.ToList();



            //load the providers from the config, if there isn't config sections then add default providers

            // and then load the defaults.

            

            LoadDefaultCompositeFileConfig(ConfigSection, http);



            DefaultCompositeFileProcessingProvider = CompositeFileProcessingProviderCollection[ConfigSection.CompositeFileElement.DefaultFileProcessingProvider];

            if (DefaultCompositeFileProcessingProvider == null)

                throw new ProviderException("Unable to load default composite file provider");



            LoadDefaultFileMapConfig(ConfigSection, http);



            DefaultFileMapProvider = FileMapProviderCollection[ConfigSection.CompositeFileElement.DefaultFileMapProvider];

            if (DefaultFileMapProvider == null)

                throw new ProviderException("Unable to load default file map provider");



            LoadDefaultMvcFileConfig(ConfigSection);



            DefaultMvcRenderer = MvcRendererCollection[ConfigSection.MvcElement.DefaultRenderer];

            if (DefaultMvcRenderer == null)

                throw new ProviderException("Unable to load default mvc renderer");



            LoadDefaultFileRegConfig(ConfigSection);



            DefaultFileRegistrationProvider = FileRegistrationProviderCollection[ConfigSection.FileRegistrationElement.DefaultProvider];

            if (DefaultFileRegistrationProvider == null)

                throw new ProviderException("Unable to load default file registration provider");



            if (string.IsNullOrEmpty(ConfigSection.LoggerType))

            {

                Logger = new NullLogger();

            }

            else

            {

                var t = Type.GetType(ConfigSection.LoggerType);

                if (!typeof(ILogger).IsAssignableFrom(t))

                {

                    throw new ArgumentException("The loggerType '" + ConfigSection.LoggerType + "' does not inherit from ClientDependency.Core.Logging.ILogger");

                }



                Logger = (ILogger)Activator.CreateInstance(t);

            }

                    

        }



        private void LoadDefaultFileRegConfig(ClientDependencySection section)

        {

            if (section.FileRegistrationElement.Providers.Count == 0)

            {

                //create new providers

                var php = new PageHeaderProvider();

                php.Initialize(PageHeaderProvider.DefaultName, null);

                FileRegistrationProviderCollection.Add(php);



                var csrp = new LazyLoadProvider();

                csrp.Initialize(LazyLoadProvider.DefaultName, null);

                FileRegistrationProviderCollection.Add(csrp);



                var lcp = new LoaderControlProvider();

                lcp.Initialize(LoaderControlProvider.DefaultName, null);

                FileRegistrationProviderCollection.Add(lcp);

            }

            else

            {

                ProvidersHelper.InstantiateProviders(section.FileRegistrationElement.Providers, FileRegistrationProviderCollection, typeof(BaseFileRegistrationProvider));

            }



        }



        private void LoadDefaultFileMapConfig(ClientDependencySection section, HttpContextBase http)

        {

            if (section.CompositeFileElement.FileMapProviders.Count == 0)

            {

                //if not specified, create default

                var fmp = new XmlFileMapper();

                fmp.Initialize(XmlFileMapper.DefaultName, null);

                fmp.Initialize(http);

                FileMapProviderCollection.Add(fmp);

            }

            else

            {

                ProvidersHelper.InstantiateProviders(section.CompositeFileElement.FileMapProviders, FileMapProviderCollection, typeof(BaseFileMapProvider));

                //since the BaseFileMapProvider is an IHttpProvider, we need to do the http init

                foreach (var p in FileMapProviderCollection.Cast<BaseFileMapProvider>())

                {

                    p.Initialize(http);

                }

            }



        }



        private void LoadDefaultCompositeFileConfig(ClientDependencySection section, HttpContextBase http)

        {

            if (section.CompositeFileElement.FileProcessingProviders.Count == 0)

            {

                var cfpp = new CompositeFileProcessingProvider();

                cfpp.Initialize(CompositeFileProcessingProvider.DefaultName, null);

                cfpp.Initialize(http);

                CompositeFileProcessingProviderCollection.Add(cfpp);

            }

            else

            {

                ProvidersHelper.InstantiateProviders(section.CompositeFileElement.FileProcessingProviders, CompositeFileProcessingProviderCollection, typeof(BaseCompositeFileProcessingProvider));

                //since the BaseCompositeFileProcessingProvider is an IHttpProvider, we need to do the http init

                foreach(var p in CompositeFileProcessingProviderCollection.Cast<BaseCompositeFileProcessingProvider>())

                {

                    p.Initialize(http);

                }

            }

            

        }



        private void LoadDefaultMvcFileConfig(ClientDependencySection section)

        {

            if (section.MvcElement.Renderers.Count == 0)

            {

                var mvc = new StandardRenderer();

                mvc.Initialize(StandardRenderer.DefaultName, null);

                MvcRendererCollection.Add(mvc);

            }

            else

            {

                ProvidersHelper.InstantiateProviders(section.MvcElement.Renderers, MvcRendererCollection, typeof(BaseRenderer));

            }



        }

    }

}