using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using HttpServer.HttpModules;
using System.IO;
using Duplicati.Server.Serialization;

namespace Duplicati.Server.WebServer
{
    public class Server
    {
        /// <summary>
        /// Option for changing the webroot folder
        /// </summary>
        public const string OPTION_WEBROOT = "webservice-webroot";
        /// <summary>
        /// Option for changing the webservice listen port
        /// </summary>
        public const string OPTION_PORT = "webservice-port";
        /// <summary>
        /// Option for changing the webservice listen interface
        /// </summary>
        public const string OPTION_INTERFACE = "webservice-interface";

        /// <summary>
        /// The default path to the web root
        /// </summary>
        public const string DEFAULT_OPTION_WEBROOT = "webroot";

        /// <summary>
        /// The default listening port
        /// </summary>
        public const int DEFAULT_OPTION_PORT = 8200;

        /// <summary>
        /// The default listening interface
        /// </summary>
        public const string DEFAULT_OPTION_INTERFACE = "loopback";

        /// <summary>
        /// The single webserver instance
        /// </summary>
        private HttpServer.HttpServer m_server;
        
        /// <summary>
        /// The webserver listening port
        /// </summary>
        public readonly int Port;
        
        /// <summary>
        /// A string that is sent out instead of password values
        /// </summary>
        public const string PASSWORD_PLACEHOLDER = "**********";

        /// <summary>
        /// Sets up the webserver and starts it
        /// </summary>
        /// <param name="options">A set of options</param>
        public Server(IDictionary<string, string> options)
        {
            int port;
            string portstring;
            IEnumerable<int> ports = null;
            options.TryGetValue(OPTION_PORT, out portstring);
            if (!string.IsNullOrEmpty(portstring))
                ports = 
                    from n in portstring.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries)
                                where int.TryParse(n, out port)
                                select int.Parse(n);

            if (ports == null || !ports.Any())
                ports = new int[] { DEFAULT_OPTION_PORT };

            string interfacestring;
            System.Net.IPAddress listenInterface;
            options.TryGetValue(OPTION_INTERFACE, out interfacestring);
            if (string.IsNullOrWhiteSpace(interfacestring))
                interfacestring = DEFAULT_OPTION_INTERFACE;
            
            if (interfacestring.Trim() == "*" || interfacestring.Trim().Equals("any", StringComparison.InvariantCultureIgnoreCase))
                listenInterface = System.Net.IPAddress.Any;
            else if (interfacestring.Trim() == "loopback")
                listenInterface = System.Net.IPAddress.Loopback;
            else
                listenInterface = System.Net.IPAddress.Parse(interfacestring);


            // If we are in hosted mode with no specified port, 
            // then try different ports
            foreach(var p in ports)
                try
                {
                    // Due to the way the server is initialized, 
                    // we cannot try to start it again on another port, 
                    // so we create a new server for each attempt
                
                    var server = CreateServer(options);
                    server.Start(listenInterface, p);
                    m_server = server;
                    m_server.ServerName = "Duplicati v" + System.Reflection.Assembly.GetExecutingAssembly().GetName().Version.ToString();
                    this.Port = p;
                    return;
                }
                catch (System.Net.Sockets.SocketException)
                {
                }
                
            throw new Exception("Unable to open a socket for listening, tried ports: " + string.Join(",", from n in ports select n.ToString()));
        }
        
        private static HttpServer.HttpServer CreateServer(IDictionary<string, string> options)
        {
            HttpServer.HttpServer server = new HttpServer.HttpServer();

            server.Add(new AuthenticationHandler());

            server.Add(new ControlHandler());

            string webroot = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
#if DEBUG
            if (!System.IO.Directory.Exists(System.IO.Path.Combine(webroot, "webroot")))
            {
                //For debug we go "../../../.." to get out of "GUI/Duplicati.GUI.TrayIcon/bin/debug"
                string tmpwebroot = System.IO.Path.GetFullPath(System.IO.Path.Combine(webroot, "..", "..", "..", ".."));
                tmpwebroot = System.IO.Path.Combine(tmpwebroot, "Server");
                if (System.IO.Directory.Exists(System.IO.Path.Combine(tmpwebroot, "webroot")))
                    webroot = tmpwebroot;
                else
                {
                    //If we are running the server standalone, we only need to exit "bin/Debug"
                    tmpwebroot = System.IO.Path.GetFullPath(System.IO.Path.Combine(webroot, "..", ".."));
                    if (System.IO.Directory.Exists(System.IO.Path.Combine(tmpwebroot, "webroot")))
                        webroot = tmpwebroot;
                }
            }
#endif

            webroot = System.IO.Path.Combine(webroot, "webroot");

            if (options.ContainsKey(OPTION_WEBROOT))
            {
                string userroot = options[OPTION_WEBROOT];
#if DEBUG
                //In debug mode we do not care where the path points
#else
                //In release mode we check that the user supplied path is located
                // in the same folders as the running application, to avoid users
                // that inadvertently expose top level folders
                if (!string.IsNullOrWhiteSpace(userroot)
                    &&
                    (
                        userroot.StartsWith(Library.Utility.Utility.AppendDirSeparator(System.Reflection.Assembly.GetExecutingAssembly().Location), Library.Utility.Utility.ClientFilenameStringComparision)
                        ||
                        userroot.StartsWith(Library.Utility.Utility.AppendDirSeparator(Program.StartupPath), Library.Utility.Utility.ClientFilenameStringComparision)
                    )
                )
#endif
                {
                    webroot = userroot;
                }
            }

            FileModule fh = new FileModule("/", webroot);
            fh.AddDefaultMimeTypes();
            fh.MimeTypes.Add("htc", "text/x-component");
            fh.MimeTypes.Add("json", "application/json");
            fh.MimeTypes.Add("map", "application/json");
            server.Add(fh);
            server.Add(new IndexHtmlHandler(System.IO.Path.Combine(webroot, "index.html")));
#if DEBUG
            //For debugging, it is nice to know when we get a 404
            server.Add(new DebugReportHandler());
#endif
            
            return server;
        }

        private class DebugReportHandler : HttpModule
        {
            public override bool Process(HttpServer.IHttpRequest request, HttpServer.IHttpResponse response, HttpServer.Sessions.IHttpSession session)
            {
                System.Diagnostics.Trace.WriteLine(string.Format("Rejecting request for {0}", request.Uri));
                return false;
            }
        }
    }
}