#region Disclaimer / License
// Copyright (C) 2015, The Duplicati Team
// http://www.duplicati.com, info@duplicati.com
// 
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
// 
#endregion
using System;
using System.Collections.Generic;
using System.Text;
using Duplicati.Library.Interface;

namespace Duplicati.Library.Backend
{
    public class WEBDAV : IBackend, IStreamingBackend
    {
        private System.Net.NetworkCredential m_userInfo;
        private string m_url;
        private string m_path;
		private string m_sanitizedUrl;
		private string m_reverseProtocolUrl;
        private string m_rawurl;
        private string m_rawurlPort;
        private bool m_useIntegratedAuthentication = false;
        private bool m_forceDigestAuthentication = false;
        private bool m_useSSL = false;
        private string m_debugPropfindFile = null;
        private readonly byte[] m_copybuffer = new byte[Duplicati.Library.Utility.Utility.DEFAULT_BUFFER_SIZE];

        /// <summary>
        /// A list of files seen in the last List operation.
        /// It is used to detect a problem with IIS where a file is listed,
        /// but IIS responds 404 because the file mapping is incorrect.
        /// </summary>
        private List<string> m_filenamelist = null;

        // According to the WEBDAV standard, the "allprop" request should return all properties, however this seems to fail on some servers (box.net).
        // I've found this description: http://www.webdav.org/specs/rfc2518.html#METHOD_PROPFIND
        //  "An empty PROPFIND request body MUST be treated as a request for the names and values of all properties."
        //
        //private static readonly byte[] PROPFIND_BODY = System.Text.Encoding.UTF8.GetBytes("<?xml version=\"1.0\"?><D:propfind xmlns:D=\"DAV:\"><D:allprop/></D:propfind>");
        private static readonly byte[] PROPFIND_BODY = new byte[0];

        public WEBDAV()
        {
        }

        public WEBDAV(string url, Dictionary<string, string> options)
        {
            var u = new Utility.Uri(url);
            u.RequireHost();

            if (!string.IsNullOrEmpty(u.Username))
            {
                m_userInfo = new System.Net.NetworkCredential();
                m_userInfo.UserName = u.Username;
                if (!string.IsNullOrEmpty(u.Password))
                    m_userInfo.Password = u.Password;
                else if (options.ContainsKey("auth-password"))
                    m_userInfo.Password = options["auth-password"];
            }
            else
            {
                if (options.ContainsKey("auth-username"))
                {
                    m_userInfo = new System.Net.NetworkCredential();
                    m_userInfo.UserName = options["auth-username"];
                    if (options.ContainsKey("auth-password"))
                        m_userInfo.Password = options["auth-password"];
                }
            }
            
            //Bugfix, see http://connect.microsoft.com/VisualStudio/feedback/details/695227/networkcredential-default-constructor-leaves-domain-null-leading-to-null-object-reference-exceptions-in-framework-code
            if (m_userInfo != null)
                m_userInfo.Domain = "";

            m_useIntegratedAuthentication = Utility.Utility.ParseBoolOption(options, "integrated-authentication");
            m_forceDigestAuthentication = Utility.Utility.ParseBoolOption(options, "force-digest-authentication");
            m_useSSL = Utility.Utility.ParseBoolOption(options, "use-ssl");

            m_url = u.SetScheme(m_useSSL ? "https" : "http").SetCredentials(null, null).SetQuery(null).ToString();
            if (!m_url.EndsWith("/"))
                m_url += "/";

            m_path = u.Path;
            if (!m_path.StartsWith("/"))
            	m_path = "/" + m_path;
            if (!m_path.EndsWith("/"))
            	m_path += "/";

            m_path = Library.Utility.Uri.UrlDecode(m_path);
            m_rawurl = new Utility.Uri(m_useSSL ? "https" : "http", u.Host, m_path).ToString();

            int port = u.Port;
            if (port <= 0)
                port = m_useSSL ? 443 : 80;

            m_rawurlPort = new Utility.Uri(m_useSSL ? "https" : "http", u.Host, m_path, null, null, null, port).ToString();
			m_sanitizedUrl = new Utility.Uri(m_useSSL ? "https" : "http", u.Host, m_path).ToString();
			m_reverseProtocolUrl = new Utility.Uri(m_useSSL ? "http" : "https", u.Host, m_path).ToString();
            options.TryGetValue("debug-propfind-file", out m_debugPropfindFile);
        }

        #region IBackend Members

        public string DisplayName
        {
            get { return Strings.WEBDAV.DisplayName; }
        }

        public string ProtocolKey
        {
            get { return "webdav"; }
        }

        public List<IFileEntry> List()
        {
            try
            {
                System.Net.HttpWebRequest req = CreateRequest("");

                req.Method = "PROPFIND";
                req.Headers.Add("Depth", "1");
                req.ContentType = "text/xml";
                req.ContentLength = PROPFIND_BODY.Length;

                Utility.AsyncHttpRequest areq = new Utility.AsyncHttpRequest(req);
                using (System.IO.Stream s = areq.GetRequestStream())
                    s.Write(PROPFIND_BODY, 0, PROPFIND_BODY.Length);
                
                System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
                using (System.Net.HttpWebResponse resp = (System.Net.HttpWebResponse)areq.GetResponse())
                {
                    int code = (int)resp.StatusCode;
                    if (code < 200 || code >= 300) //For some reason Mono does not throw this automatically
                        throw new System.Net.WebException(resp.StatusDescription, null, System.Net.WebExceptionStatus.ProtocolError, resp);

                    if (!string.IsNullOrEmpty(m_debugPropfindFile))
                    {
                        using (System.IO.FileStream fs = new System.IO.FileStream(m_debugPropfindFile, System.IO.FileMode.Create, System.IO.FileAccess.Write, System.IO.FileShare.None))
                            Utility.Utility.CopyStream(areq.GetResponseStream(), fs, false, m_copybuffer);

                        doc.Load(m_debugPropfindFile);
                    }
                    else
                        doc.Load(areq.GetResponseStream());
                }

                System.Xml.XmlNamespaceManager nm = new System.Xml.XmlNamespaceManager(doc.NameTable);
                nm.AddNamespace("D", "DAV:");

                List<IFileEntry> files = new List<IFileEntry>();
                m_filenamelist = new List<string>();

                foreach (System.Xml.XmlNode n in doc.SelectNodes("D:multistatus/D:response/D:href", nm))
                {
                    //IIS uses %20 for spaces and %2B for +
                    //Apache uses %20 for spaces and + for +
                    string name = Library.Utility.Uri.UrlDecode(n.InnerText.Replace("+", "%2B"));

                    string cmp_path;
					
					//TODO: This list is getting ridiculous, should change to regexps
					
                    if (name.StartsWith(m_url))
                        cmp_path = m_url;
                    else if (name.StartsWith(m_rawurl))
                        cmp_path = m_rawurl;
                    else if (name.StartsWith(m_rawurlPort))
                        cmp_path = m_rawurlPort;
                    else if (name.StartsWith(m_path))
                        cmp_path = m_path;
                    else if (name.StartsWith(m_sanitizedUrl))
                        cmp_path = m_sanitizedUrl;
                    else if (name.StartsWith(m_reverseProtocolUrl))
                        cmp_path = m_reverseProtocolUrl;
                    else
                        continue;

                    if (name.Length <= cmp_path.Length)
                        continue;

                    name = name.Substring(cmp_path.Length);

                    long size = -1;
                    DateTime lastAccess = new DateTime();
                    DateTime lastModified = new DateTime();
                    bool isCollection = false;

                    System.Xml.XmlNode stat = n.ParentNode.SelectSingleNode("D:propstat/D:prop", nm);
                    if (stat != null)
                    {
                        System.Xml.XmlNode s = stat.SelectSingleNode("D:getcontentlength", nm);
                        if (s != null)
                            size = long.Parse(s.InnerText);
                        s = stat.SelectSingleNode("D:getlastmodified", nm);
                        if (s != null)
                            try
                            {
                                //Not important if this succeeds
                                lastAccess = lastModified = DateTime.Parse(s.InnerText, System.Globalization.CultureInfo.InvariantCulture);
                            }
                            catch { }

                        s = stat.SelectSingleNode("D:iscollection", nm);
                        if (s != null)
                            isCollection = s.InnerText.Trim() == "1";
                        else
                            isCollection = (stat.SelectSingleNode("D:resourcetype/D:collection", nm) != null);
                    }

                    FileEntry fe = new FileEntry(name, size, lastAccess, lastModified);
                    fe.IsFolder = isCollection;
                    files.Add(fe);
                    m_filenamelist.Add(name);
                }

                return files;
            }
            catch (System.Net.WebException wex)
            {
                if (wex.Response as System.Net.HttpWebResponse != null &&
                        ((wex.Response as System.Net.HttpWebResponse).StatusCode == System.Net.HttpStatusCode.NotFound || (wex.Response as System.Net.HttpWebResponse).StatusCode == System.Net.HttpStatusCode.Conflict))
                    throw new Interface.FolderMissingException(Strings.WEBDAV.MissingFolderError(m_path, wex.Message), wex);

                throw;
            }
        }

        public void Put(string remotename, string filename)
        {
            using (System.IO.FileStream fs = System.IO.File.OpenRead(filename))
                Put(remotename, fs);
        }

        public void Get(string remotename, string filename)
        {
            using (System.IO.FileStream fs = System.IO.File.Create(filename))
                Get(remotename, fs);
        }

        public void Delete(string remotename)
        {
            try
            {
                System.Net.HttpWebRequest req = CreateRequest(remotename);
                req.Method = "DELETE";
                Utility.AsyncHttpRequest areq = new Utility.AsyncHttpRequest(req);
                using (System.Net.HttpWebResponse resp = (System.Net.HttpWebResponse)areq.GetResponse())
                {
                    if (resp.StatusCode == System.Net.HttpStatusCode.NotFound)
                        throw new FileMissingException();

                    int code = (int)resp.StatusCode;
                    if (code < 200 || code >= 300) //For some reason Mono does not throw this automatically
                        throw new System.Net.WebException(resp.StatusDescription, null, System.Net.WebExceptionStatus.ProtocolError, resp);
                }
            } 
            catch (System.Net.WebException wex)
            {
                if (wex.Response is System.Net.HttpWebResponse && ((System.Net.HttpWebResponse)wex.Response).StatusCode == System.Net.HttpStatusCode.NotFound)
                    throw new FileMissingException(wex);
                else
                    throw;
            }
        }

        public IList<ICommandLineArgument> SupportedCommands
        {
            get 
            {
                return new List<ICommandLineArgument>(new ICommandLineArgument[] {
                    new CommandLineArgument("auth-password", CommandLineArgument.ArgumentType.Password, Strings.WEBDAV.DescriptionAuthPasswordShort, Strings.WEBDAV.DescriptionAuthPasswordLong),
                    new CommandLineArgument("auth-username", CommandLineArgument.ArgumentType.String, Strings.WEBDAV.DescriptionAuthUsernameShort, Strings.WEBDAV.DescriptionAuthUsernameLong),
                    new CommandLineArgument("integrated-authentication", CommandLineArgument.ArgumentType.Boolean, Strings.WEBDAV.DescriptionIntegratedAuthenticationShort, Strings.WEBDAV.DescriptionIntegratedAuthenticationLong),
                    new CommandLineArgument("force-digest-authentication", CommandLineArgument.ArgumentType.Boolean, Strings.WEBDAV.DescriptionForceDigestShort, Strings.WEBDAV.DescriptionForceDigestLong),
                    new CommandLineArgument("use-ssl", CommandLineArgument.ArgumentType.Boolean, Strings.WEBDAV.DescriptionUseSSLShort, Strings.WEBDAV.DescriptionUseSSLLong),
                    new CommandLineArgument("debug-propfind-file", CommandLineArgument.ArgumentType.Path, Strings.WEBDAV.DescriptionDebugPropfindShort, Strings.WEBDAV.DescriptionDebugPropfindLong),
                });
            }
        }

        public string Description
        {
            get { return Strings.WEBDAV.Description; }
        }

        public void Test()
        {
            List();
        }

        public void CreateFolder()
        {
            System.Net.HttpWebRequest req = CreateRequest("");
            req.Method = System.Net.WebRequestMethods.Http.MkCol;
            req.KeepAlive = false;
            Utility.AsyncHttpRequest areq = new Utility.AsyncHttpRequest(req);
            using (System.Net.HttpWebResponse resp = (System.Net.HttpWebResponse)areq.GetResponse())
            {
                int code = (int)resp.StatusCode;
                if (code < 200 || code >= 300) //For some reason Mono does not throw this automatically
                    throw new System.Net.WebException(resp.StatusDescription, null, System.Net.WebExceptionStatus.ProtocolError, resp);
            }
        }

        #endregion

        #region IDisposable Members

        public void Dispose()
        {
        }

        #endregion

        private System.Net.HttpWebRequest CreateRequest(string remotename)
        {
            System.Net.HttpWebRequest req = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(m_url + Library.Utility.Uri.UrlEncode(remotename).Replace("+", "%20"));
            if (m_useIntegratedAuthentication)
            {
                req.UseDefaultCredentials = true;
            }
            else if (m_forceDigestAuthentication)
            {
                System.Net.CredentialCache cred = new System.Net.CredentialCache();
                cred.Add(new Uri(m_url), "Digest", m_userInfo);
                req.Credentials = cred;
            }
            else
			{
                req.Credentials = m_userInfo;
                //We need this under Mono for some reason,
                // and it appears some servers require this as well
				req.PreAuthenticate = true; 
			}

            req.KeepAlive = false;
            req.UserAgent = "Duplicati WEBDAV Client v" + System.Reflection.Assembly.GetExecutingAssembly().GetName().Version.ToString();

            return req;
        }

        #region IStreamingBackend Members

        public void Put(string remotename, System.IO.Stream stream)
        {
            try
            {
                System.Net.HttpWebRequest req = CreateRequest(remotename);
                req.Method = System.Net.WebRequestMethods.Http.Put;
                req.ContentType = "application/octet-stream";

                try { req.ContentLength = stream.Length; }
                catch { }

                Utility.AsyncHttpRequest areq = new Utility.AsyncHttpRequest(req);
                using (System.IO.Stream s = areq.GetRequestStream())
                    Utility.Utility.CopyStream(stream, s, true, m_copybuffer);

                using (System.Net.HttpWebResponse resp = (System.Net.HttpWebResponse)areq.GetResponse())
                {
                    int code = (int)resp.StatusCode;
                    if (code < 200 || code >= 300) //For some reason Mono does not throw this automatically
                        throw new System.Net.WebException(resp.StatusDescription, null, System.Net.WebExceptionStatus.ProtocolError, resp);
                }
            }
            catch (System.Net.WebException wex)
            {
                //Convert to better exception
                if (wex.Response as System.Net.HttpWebResponse != null)
                    if ((wex.Response as System.Net.HttpWebResponse).StatusCode == System.Net.HttpStatusCode.Conflict || (wex.Response as System.Net.HttpWebResponse).StatusCode == System.Net.HttpStatusCode.NotFound)
                        throw new Interface.FolderMissingException(Strings.WEBDAV.MissingFolderError(m_path, wex.Message), wex);

                throw;
            }
        }

        public void Get(string remotename, System.IO.Stream stream)
        {
            System.Net.HttpWebRequest req = CreateRequest(remotename);
            req.Method = System.Net.WebRequestMethods.Http.Get;

            try
            {
                Utility.AsyncHttpRequest areq = new Utility.AsyncHttpRequest(req);
                using (System.Net.HttpWebResponse resp = (System.Net.HttpWebResponse)areq.GetResponse())
                {
                    int code = (int)resp.StatusCode;
                    if (code < 200 || code >= 300) //For some reason Mono does not throw this automatically
                        throw new System.Net.WebException(resp.StatusDescription, null, System.Net.WebExceptionStatus.ProtocolError, resp);

                    using (System.IO.Stream s = areq.GetResponseStream())
                        Utility.Utility.CopyStream(s, stream, true, m_copybuffer);
                }
            }
            catch (System.Net.WebException wex)
            {
                if (wex.Response as System.Net.HttpWebResponse != null)
                {
                    if ((wex.Response as System.Net.HttpWebResponse).StatusCode == System.Net.HttpStatusCode.Conflict)
                        throw new Interface.FolderMissingException(Strings.WEBDAV.MissingFolderError(m_path, wex.Message), wex);

                    if
                    (
                        (wex.Response as System.Net.HttpWebResponse).StatusCode == System.Net.HttpStatusCode.NotFound
                        &&
                        m_filenamelist != null
                        &&
                        m_filenamelist.Contains(remotename)
                    )
                        throw new Exception(Strings.WEBDAV.SeenThenNotFoundError(m_path, remotename, System.IO.Path.GetExtension(remotename), wex.Message), wex);
                }

                throw;
            }
        }

        #endregion
    }
}