/*

Copyright (C) 2008 Max Semenik



This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.



This program 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 General Public License for more details.



You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

*/

using System;

using System.Collections.Generic;

using System.Text;

using System.Net;

using System.Reflection;

using System.Web;

using System.IO;

using System.Xml;

using System.Threading;

using System.Text.RegularExpressions;



namespace WikiFunctions.API

{

    //TODO: refactor XML parsing

    //TODO: generalise edit token retrieval

    /// <summary>

    /// This class edits MediaWiki sites using api.php

    /// </summary>

    /// <remarks>

    /// MediaWiki API manual: http://www.mediawiki.org/wiki/API

    /// Site prerequisites: MediaWiki 1.13+ with the following settings:

    /// * $wgEnableAPI = true; (enabled by default in DefaultSettings.php)

    /// * $wgEnableWriteAPI = true;

    /// * AssertEdit extension installed (http://www.mediawiki.org/wiki/Extension:Assert_Edit)

    /// </remarks>

    public class ApiEdit : IApiEdit

    {

        /// <summary>

        /// 

        /// </summary>

        private ApiEdit()

        {

            Cookies = new CookieContainer();

            User = new UserInfo();

            NewMessageThrows = true;

        }



        /// <summary>

        /// Creates a new instance of the ApiEdit class

        /// </summary>

        /// <param name="url">Path to scripts on server</param>

        public ApiEdit(string url)

            : this(url, false)

        {

        }



        /// <summary>

        /// Creates a new instance of the ApiEdit class

        /// </summary>

        /// <param name="url">Path to scripts on server</param>

        /// <param name="usePHP5">Whether a .php5 extension is to be used</param>

        public ApiEdit(string url, bool usePHP5)

            : this()

        {

            if (string.IsNullOrEmpty(url)) throw new ArgumentException("Invalid URL specified", "url");

            if (!url.StartsWith("http://")) throw new NotSupportedException("Only editing via HTTP is currently supported");



            URL = url;

            PHP5 = usePHP5;

            ApiURL = URL + "api.php" + (PHP5 ? "5" : "");

            Maxlag = 5;



            IWebProxy proxy;

            if (ProxyCache.TryGetValue(url, out proxy))

            {

                ProxySettings = proxy;

            }

            else

            {

                ProxySettings = WebRequest.GetSystemWebProxy();

                if (ProxySettings.IsBypassed(new Uri(url)))

                {

                    ProxySettings = null;

                }

                ProxyCache.Add(url, ProxySettings);

            }

        }



        public IApiEdit Clone()

        {

            return new ApiEdit

                       {

                           URL = URL,

                           ApiURL = ApiURL,

                           PHP5 = PHP5,

                           Maxlag = Maxlag,

                           Cookies = Cookies,

                           ProxySettings = ProxySettings,

                           User = User

                       };

        }



        #region Properties



        /// <summary>

        /// Path to scripts on server

        /// </summary>

        public string URL { get; private set; }



        /// <summary>

        /// 

        /// </summary>

        public string ApiURL { get; private set; }



        /// <summary>

        /// 

        /// </summary>

        private string Server

        { get { return "http://" + new Uri(URL).Host; } }



        /// <summary>

        /// 

        /// </summary>

        public bool PHP5 { get; private set; }



        /// <summary>

        /// Maxlag parameter of every request (http://www.mediawiki.org/wiki/Manual:Maxlag_parameter)

        /// </summary>

        public int Maxlag { get; set; }



        /// <summary>

        /// 

        /// </summary>

        public bool NewMessageThrows

        { get; set; }



        /// <summary>

        /// Action for which we have edit token

        /// </summary>

        public string Action { get; private set; }



        /// <summary>

        /// Name of the page currently being edited

        /// </summary>

        public PageInfo Page

        { get; private set; }



        /// <summary>

        /// 

        /// </summary>

        public string HtmlHeaders

        { get; private set; }



        /// <summary>

        /// Cookies stored between requests

        /// </summary>

        public CookieContainer Cookies { get; private set; }

        #endregion



        /// <summary>

        /// Resets all internal variables, discarding edit tokens and so on,

        /// but does not logs off

        /// </summary>

        public void Reset()

        {

            Action = null;

            Page = new PageInfo();

            Aborting = false;

            Request = null;

        }



        /// <summary>

        /// 

        /// </summary>

        public void Abort()

        {

            Aborting = true;

            Request.Abort();

            Thread.Sleep(1);

            Aborting = false;

        }



        /// <summary>

        /// This is a hack required for some multilingual Wikimedia projects,

        /// where CentralAuth returns cookies with a redundant domain restriction.

        /// </summary>

        private void AdjustCookies()

        {

            string host = new Uri(URL).Host;

            var newCookies = new CookieContainer();

            var urls = new[] { new Uri(URL), new Uri("http://fnord." + host) };

            foreach (var u in urls)

            {

                foreach (Cookie c in Cookies.GetCookies(u))

                {

                    c.Domain = host;

                    newCookies.Add(c);

                }

            }



            Cookies = newCookies;

        }



        #region URL stuff

        /// <summary>

        /// 

        /// </summary>

        /// <param name="request"></param>

        /// <returns></returns>

        protected static string BuildQuery(string[,] request)

        {

            StringBuilder sb = new StringBuilder();

            for (int i = 0; i <= request.GetUpperBound(0); i++)

            {

                string s = request[i, 0];

                if (string.IsNullOrEmpty(s)) continue;

                sb.Append('&');

                sb.Append(s);



                s = request[i, 1];

                if (s != null) // empty string is a valid parameter value!

                {

                    sb.Append('=');

                    sb.Append(HttpUtility.UrlEncode(s));

                }

            }



            return sb.ToString();

        }



        /// <summary>

        /// 

        /// </summary>

        /// <param name="titles"></param>

        /// <returns></returns>

        protected static string Titles(params string[] titles)

        {

            for (int i = 0; i < titles.Length; i++) titles[i] = Tools.WikiEncode(titles[i]);

            if (titles.Length > 0) return "&titles=" + string.Join("|", titles);



            return "";

        }



        /// <summary>

        /// 

        /// </summary>

        /// <param name="paramName"></param>

        /// <param name="titles"></param>

        /// <returns></returns>

        protected static string NamedTitles(string paramName, params string[] titles)

        {

            for (int i = 0; i < titles.Length; i++) titles[i] = Tools.WikiEncode(titles[i]);

            if (titles.Length > 0) return "&" + paramName + "=" + string.Join("|", titles);

            return "";

        }



        protected string AppendOptions(string url, ActionOptions options)

        {

            if ((options & ActionOptions.CheckMaxlag) > 0 && Maxlag > 0)

                url += "&maxlag=" + Maxlag;



            if ((options & ActionOptions.RequireLogin) > 0)

                url += "&assert=user";



            if ((options & ActionOptions.CheckNewMessages) > 0)

                url += "&meta=userinfo&uiprop=hasmsg";



            return url;

        }



        /// <summary>

        /// 

        /// </summary>

        /// <param name="request"></param>

        /// <param name="options"></param>

        /// <returns></returns>

        protected string BuildUrl(string[,] request, ActionOptions options)

        {

            string url = ApiURL + "?format=xml" + BuildQuery(request);



            return AppendOptions(url, options);

        }



        /// <summary>

        /// 

        /// </summary>

        /// <param name="request"></param>

        /// <returns></returns>

        protected string BuildUrl(string[,] request)

        {

            return BuildUrl(request, ActionOptions.None);

        }

        #endregion



        #region Network access

        private static readonly Dictionary<string, IWebProxy> ProxyCache = new Dictionary<string, IWebProxy>();

        private IWebProxy ProxySettings;



        private static readonly string UserAgent = string.Format("WikiFunctions ApiEdit/{0} ({1}; .NET CLR {2})",

                                                                 Assembly.GetExecutingAssembly().GetName().Version,

                                                                 Environment.OSVersion.VersionString,

                                                                 Environment.Version);



        /// <summary>

        /// 

        /// </summary>

        /// <param name="url"></param>

        /// <returns></returns>

        protected HttpWebRequest CreateRequest(string url)

        {

            if (Globals.UnitTestMode) throw new Exception("You shouldn't access Wikipedia from unit tests");



            ServicePointManager.Expect100Continue = false;

            HttpWebRequest res = (HttpWebRequest)WebRequest.Create(url);

            res.ServicePoint.Expect100Continue = false;

            res.Expect = "";

            if (ProxySettings != null)

            {

                res.Proxy = ProxySettings;

                res.UseDefaultCredentials = true;

            }

            res.UserAgent = UserAgent;

            res.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip;



            // SECURITY: don't send cookies to third-party sites

            if (url.StartsWith(URL)) res.CookieContainer = Cookies;



            return res;

        }



        private bool Aborting;

        private HttpWebRequest Request;



        /// <summary>

        /// 

        /// </summary>

        /// <param name="req"></param>

        /// <returns></returns>

        protected string GetResponseString(HttpWebRequest req)

        {

            Request = req;



            try

            {

                using (WebResponse resp = req.GetResponse())

                {

                    using (StreamReader sr = new StreamReader(resp.GetResponseStream()))

                    {

                        return sr.ReadToEnd();

                    }

                }

            }

            catch (WebException ex)

            {

                var resp = (HttpWebResponse)ex.Response;

                if (resp == null) throw;

                switch (resp.StatusCode)

                {

                    case HttpStatusCode.NotFound /*404*/:

                        return ""; // emulate the behaviour of Tools.HttpGet()

                }



                // just reclassifying

                if (ex.Status == WebExceptionStatus.RequestCanceled)

                {

                    throw new AbortedException(this);

                }

                else

                {

                    throw;

                }

            }

            finally

            {

                Request = null;

            }

        }



        private string[,] lastPostParameters;

        private string lastGetUrl;



        /// <summary>

        /// 

        /// </summary>

        /// <param name="get"></param>

        /// <param name="post"></param>

        /// <param name="options"></param>

        /// <returns></returns>

        protected string HttpPost(string[,] get, string[,] post, ActionOptions options)

        {

            string url = BuildUrl(get, options);



            lastGetUrl = url;

            lastPostParameters = post;



            string query = BuildQuery(post);

            byte[] postData = Encoding.UTF8.GetBytes(query);



            HttpWebRequest req = CreateRequest(url);

            req.Method = "POST";

            req.ContentType = "application/x-www-form-urlencoded";

            req.ContentLength = postData.Length;

            using (Stream rs = req.GetRequestStream())

            {

                rs.Write(postData, 0, postData.Length);

            }

            return GetResponseString(req);

        }



        /// <summary>

        /// 

        /// </summary>

        /// <param name="get"></param>

        /// <param name="post"></param>

        /// <returns></returns>

        protected string HttpPost(string[,] get, string[,] post)

        {

            return HttpPost(get, post, ActionOptions.None);

        }



        /// <summary>

        /// Performs a HTTP request

        /// </summary>

        /// <param name="request"></param>

        /// <param name="options"></param>

        /// <returns>Text received</returns>

        protected string HttpGet(string[,] request, ActionOptions options)

        {

            string url = BuildUrl(request, options);

            lastGetUrl = url;



            return HttpGet(url);

        }



        /// <summary>

        /// Performs a HTTP request

        /// </summary>

        /// <param name="request"></param>

        /// <returns>Text received</returns>

        protected string HttpGet(string[,] request)

        {

            return HttpGet(request, ActionOptions.None);

        }



        /// <summary>

        /// Performs a HTTP request

        /// </summary>

        /// <param name="url"></param>

        /// <returns>Text received</returns>

        public string HttpGet(string url)

        {

            return GetResponseString(CreateRequest(url));

        }

        #endregion



        #region Login / user props

        public void Login(string username, string password)

        {

            if (string.IsNullOrEmpty(username)) throw new ArgumentException("Username required", "username");

            //if (string.IsNullOrEmpty(password)) throw new ArgumentException("Password required", "password");



            Reset();

            User = new UserInfo(); // we don't know for sure what will be our status in case of exception



            string result = HttpPost(new[,] { { "action", "login" } },

                                     new[,] 

                                     { 

                                        { "lgname", username }, 

                                        { "lgpassword", password }

                                     }

                                );



            XmlReader xr = XmlReader.Create(new StringReader(result));

            xr.ReadToFollowing("login");



            if (xr.GetAttribute("result").Equals("NeedToken", StringComparison.InvariantCultureIgnoreCase))

            {

                AdjustCookies();

                string token = xr.GetAttribute("token");



                result = HttpPost(new[,] { { "action", "login" } },

                                  new[,]

                                      {

                                          {"lgname", username},

                                          {"lgpassword", password},

                                          {"lgtoken", token}

                                      }

                    );



                xr = XmlReader.Create(new StringReader(result));

                xr.ReadToFollowing("login");

            }



            string status = xr.GetAttribute("result");



            if (!status.Equals("Success", StringComparison.InvariantCultureIgnoreCase))

            {

                throw new LoginException(this, status);

            }



            CheckForErrors(result, "login");

            AdjustCookies();



            RefreshUserInfo();

        }



        public void Logout()

        {

            Reset();

            User = new UserInfo();

            string result = HttpGet(new[,] { { "action", "logout" } });

            CheckForErrors(result, "logout");

        }



        public void Watch(string title)

        {

            if (string.IsNullOrEmpty(title)) throw new ArgumentException("Page name required", "title");



            //Reset();

            string result = HttpPost(new[,]

                                         {

                                             {"action", "watch"},

                                         },

                                     new[,]

                                         {

                                             {"title", title}

                                         },

                                         ActionOptions.None);

            CheckForErrors(result, "watch");

        }



        public void Unwatch(string title)

        {

            if (string.IsNullOrEmpty(title)) throw new ArgumentException("Page name required", "title");



            //Reset();

            string result = HttpPost(new[,]

                                         {

                                             {"action", "watch"},

                                         },

                                     new[,]

                                         {

                                             {"title", title},

                                             {"unwatch", null}

                                         });

            CheckForErrors(result, "watch");

        }



        public UserInfo User { get; private set; }



        public void RefreshUserInfo()

        {

            Reset();

            User = new UserInfo();



            string result = HttpPost(new[,] { { "action", "query" } },

                         new[,] {

                            { "meta", "userinfo" },

                            { "uiprop", "blockinfo|hasmsg|groups|rights" }

                         });



            var xml = CheckForErrors(result, "userinfo");



            User = new UserInfo(xml);

        }



        #endregion



        #region Page modification



        /// <summary>

        /// Opens the wiki page for editing

        /// </summary>

        /// <param name="title">The wiki page title</param>

        /// <returns>The current content of the wiki page</returns>

        public string Open(string title)

        {

            return Open(title, false);

        }



        /// <summary>

        /// Opens the wiki page for editing

        /// </summary>

        /// <param name="title">The wiki page title</param>

        /// <param name="resolveRedirects"></param>

        /// <returns>The current content of the wiki page</returns>

        public string Open(string title, bool resolveRedirects)

        {

            if (string.IsNullOrEmpty(title)) 

                throw new ArgumentException("Page name required", "title");

            

            if (!User.IsLoggedIn) 

                throw new LoggedOffException(this);



            Reset();



            // action=query&prop=info|revisions&intoken=edit&titles=Main%20Page&rvprop=timestamp|user|comment|content

            string result = HttpGet(new[,]

                                        {

                                            {"action", "query"},

                                            {"prop", "info|revisions"},

                                            {"intoken", "edit"},

                                            {"titles", title},

                                            {"inprop", "protection|watched"},

                                            {"rvprop", "content|timestamp"}, // timestamp|user|comment|

                                            {resolveRedirects ? "redirects" : null, null}

                                        },

                                    ActionOptions.All);



            CheckForErrors(result, "query");



            try

            {

                Page = new PageInfo(result);



                Action = "edit";

            }

            catch (Exception ex)

            {

                throw new BrokenXmlException(this, ex);

            }



            return Page.Text;

        }



        public SaveInfo Save(string pageText, string summary, bool minor, WatchOptions watch)

        {

            if (string.IsNullOrEmpty(pageText) && !Page.Exists) throw new ArgumentException("Can't save empty pages", "pageText");

            //if (string.IsNullOrEmpty(summary)) throw new ArgumentException("Edit summary required", "summary");

            if (Action != "edit") throw new ApiException(this, "This page is not opened properly for editing");

            if (string.IsNullOrEmpty(Page.EditToken)) throw new ApiException(this, "Edit token is needed to edit pages");



            pageText = Tools.ConvertFromLocalLineEndings(pageText);



            string result = HttpPost(

                new[,]

                {

                    { "action", "edit" },

                    { "title", Page.Title },

                    { minor ? "minor" : null, null },

                    { WatchOptionsToParam(watch), null },

                    { User.IsBot ? "bot" : null, null }

                },

                new[,]

                {// order matters here - https://bugzilla.wikimedia.org/show_bug.cgi?id=14210#c4

                    { "md5", MD5(pageText) },

                    { "summary", summary },

                    { "basetimestamp", Page.Timestamp },

                    { "text", pageText },

                    { "starttimestamp", Page.TokenTimestamp },

                    { "token", Page.EditToken }

                },

                ActionOptions.All);



            var xml = CheckForErrors(result, "edit");

            Reset();

            return new SaveInfo(xml);

        }



        public void Delete(string title, string reason)

        {

            Delete(title, reason, false);

        }



        public void Delete(string title, string reason, bool watch)

        {

            if (string.IsNullOrEmpty(title)) throw new ArgumentException("Page name required", "title");

            if (string.IsNullOrEmpty(reason)) throw new ArgumentException("Deletion reason required", "reason");



            Reset();

            Action = "delete";



            string result = HttpGet(

                new[,]

                    {

                        { "action", "query" },

                        { "prop", "info" },

                        { "intoken", "delete" },

                        { "titles", title },

                        //{ User.IsBot ? "bot" : null, null },

                        { watch ? "watch" : null, null }



                    },

                    ActionOptions.All);



            CheckForErrors(result);



            try

            {

                XmlReader xr = XmlReader.Create(new StringReader(result));

                if (!xr.ReadToFollowing("page")) throw new Exception("Cannot find <page> element");

                Page.EditToken = xr.GetAttribute("deletetoken");

            }

            catch (Exception ex)

            {

                throw new BrokenXmlException(this, ex);

            }



            if (Aborting) throw new AbortedException(this);



            result = HttpPost(

                new[,]

                {

                    { "action", "delete" }

                },

                new[,]

                {

                    { "title", title },

                    { "token", Page.EditToken },

                    { "reason", reason }

                },

                ActionOptions.All);



            CheckForErrors(result);



            Reset();

        }



        public void Protect(string title, string reason, TimeSpan expiry, string edit, string move)

        {

            Protect(title, reason, expiry.ToString(), edit, move, false, false);

        }



        public void Protect(string title, string reason, string expiry, string edit, string move)

        {

            Protect(title, reason, expiry, edit, move, false, false);

        }



        public void Protect(string title, string reason, TimeSpan expiry, string edit, string move, bool cascade, bool watch)

        {

            Protect(title, reason, expiry.ToString(), edit, move, cascade, watch);

        }



        public void Protect(string title, string reason, string expiry, string edit, string move, bool cascade, bool watch)

        {

            if (string.IsNullOrEmpty(title)) throw new ArgumentException("Page name required", "title");

            if (string.IsNullOrEmpty(reason)) throw new ArgumentException("Deletion reason required", "reason");



            Reset();

            Action = "protect";



            string result = HttpGet(

                new[,]

                    {

                        { "action", "query" },

                        { "prop", "info" },

                        { "intoken", "protect" },

                        { "titles", title },



                    },

                    ActionOptions.All);



            CheckForErrors(result);



            try

            {

                XmlReader xr = XmlReader.Create(new StringReader(result));

                if (!xr.ReadToFollowing("page")) throw new Exception("Cannot find <page> element");

                Page.EditToken = xr.GetAttribute("protecttoken");

            }

            catch (Exception ex)

            {

                throw new BrokenXmlException(this, ex);

            }



            if (Aborting) throw new AbortedException(this);



            result = HttpPost(

                new[,]

                    {

                        {"action", "protect"}

                    },

                new[,]

                    {

                        { "title", title },

                        { "token", Page.EditToken },

                        { "reason", reason },

                        { "protections", "edit=" + edit + "|move=" + move },

                        { string.IsNullOrEmpty(expiry) ? "" : "expiry", string.IsNullOrEmpty(expiry) ? "" : expiry + "|" + expiry },

                        { cascade ? "cascade" : null, null },

                        //{ User.IsBot ? "bot" : null, null },

                        { watch ? "watch" : null, null }

                    },

                    ActionOptions.All);



            CheckForErrors(result);



            Reset();

        }



        //Todo: Remove duplication against void Move(string title, string newTitle, string reason, bool moveTalk, bool noRedirect, bool watch)

        public void Move(int titleid, string newTitle, string reason, bool moveTalk, bool noRedirect, bool watch)

        {

            if (string.IsNullOrEmpty(newTitle)) throw new ArgumentException("Target page title required", "newTitle");

            if (string.IsNullOrEmpty(reason)) throw new ArgumentException("Page rename reason required", "reason");





            Reset();

            Action = "move";



            string result = HttpGet(

                new[,]

                    {

                        { "action", "query" },

                        { "prop", "info" },

                        { "intoken", "move" },

                        { "titles", newTitle },

                    },

                    ActionOptions.All);



            CheckForErrors(result);



            bool invalid;

            try

            {

                XmlReader xr = XmlReader.Create(new StringReader(result));

                if (!xr.ReadToFollowing("page")) throw new Exception("Cannot find <page> element");



                invalid = xr.MoveToAttribute("invalid");



                Page.EditToken = xr.GetAttribute("movetoken");

            }

            catch (Exception ex)

            {

                throw new BrokenXmlException(this, ex);

            }



            if (Aborting) throw new AbortedException(this);



            if (invalid) throw new ApiException(this, "invalidnewtitle", new ArgumentException("Target page invalid", "newTitle"));



            result = HttpPost(

                new[,]

                    {

                        { "action", "move" }

                    },

                new[,]

                    {

                        { "fromid", titleid.ToString() },

                        { "to", newTitle },

                        { "token", Page.EditToken },

                        { "reason", reason },

                        { "protections", "" },

                        { moveTalk ? "movetalk" : null, null },

                        { noRedirect ? "noredirect" : null, null },

                        { User.IsBot ? "bot" : null, null },

                        { watch ? "watch" : null, null }

                    },

                ActionOptions.All);



            CheckForErrors(result);



            Reset();

        }



        public void Move(string title, string newTitle, string reason)

        {

            Move(title, newTitle, reason, true, false, false);

        }



        public void Move(string title, string newTitle, string reason, bool moveTalk, bool noRedirect)

        {

            Move(title, newTitle, reason, moveTalk, noRedirect, false);

        }



        public void Move(string title, string newTitle, string reason, bool moveTalk, bool noRedirect, bool watch)

        {

            if (string.IsNullOrEmpty(title)) throw new ArgumentException("Page title required", "title");

            if (string.IsNullOrEmpty(newTitle)) throw new ArgumentException("Target page title required", "newTitle");

            if (string.IsNullOrEmpty(reason)) throw new ArgumentException("Page rename reason required", "reason");



            if (title == newTitle) throw new ArgumentException("Page cannot be moved to the same title");



            Reset();

            Action = "move";



            string result = HttpGet(

                new[,]

                    {

                        { "action", "query" },

                        { "prop", "info" },

                        { "intoken", "move" },

                        { "titles", title + "|" + newTitle },



                    },

                    ActionOptions.All);



            CheckForErrors(result);



            bool invalid;

            try

            {

                XmlReader xr = XmlReader.Create(new StringReader(result));

                if (!xr.ReadToFollowing("page")) throw new Exception("Cannot find <page> element");



                invalid = xr.MoveToAttribute("invalid");



                Page.EditToken = xr.GetAttribute("movetoken");

            }

            catch (Exception ex)

            {

                throw new BrokenXmlException(this, ex);

            }



            if (Aborting) throw new AbortedException(this);



            if (invalid) throw new ApiException(this, "invalidnewtitle", new ArgumentException("Target page invalid", "newTitle"));



            result = HttpPost(

                new[,]

                    {

                        { "action", "move" }

                    },

                new[,]

                    {

                        { "from", title },

                        { "to", newTitle },

                        { "token", Page.EditToken },

                        { "reason", reason },

                        { "protections", "" },

                        { moveTalk ? "movetalk" : null, null },

                        { noRedirect ? "noredirect" : null, null },

                        //{ User.IsBot ? "bot" : null, null },

                        { watch ? "watch" : null, null }

                    },

                ActionOptions.All);



            CheckForErrors(result);



            Reset();

        }



        #endregion



        #region Query Api

        public string QueryApi(string queryParamters)

        {

            if (string.IsNullOrEmpty(queryParamters)) throw new ArgumentException("queryParamters cannot be null/empty", "queryParamters");



            string result = HttpGet(ApiURL + "?action=query&format=xml&" + queryParamters); //Should we be checking for maxlag?



            CheckForErrors(result, "query");



            return result;

        }



        #endregion



        #region Wikitext operations



        private string ExpandRelativeUrls(string html)

        {

            return html.Replace(" href=\"/", " href=\"" + Server + "/")

                .Replace(" src=\"/", " src=\"" + Server + "/");

        }



        private static readonly Regex ExtractCssAndJs = new Regex(@"("

            + @"<!--\[if .*?-->"

            + @"|<style\b.*?>.*?</style>"

            + @"|<link rel=""stylesheet"".*?/\s?>"

            //+ @"|<script type=""text/javascript"".*?</script>"

            + ")",

            RegexOptions.Singleline | RegexOptions.Compiled);



        /// <summary>

        /// Loads wiki's UI HTML and scrapes everything we need to make correct previews

        /// </summary>

        private void EnsureHtmlHeadersLoaded()

        {

            if (!string.IsNullOrEmpty(HtmlHeaders)) return;



            string result = HttpGet(

                new[,]

                    {

                        {"action", "parse"},

                        {"prop", "headhtml"}

                    },

                    ActionOptions.None

                );



            result = Tools.StringBetween(Tools.UnescapeXML(result), "<head>", "</head>");

            StringBuilder extracted = new StringBuilder(2048);



            foreach (Match m in ExtractCssAndJs.Matches(result))

            {

                extracted.Append(m.Value);

                extracted.Append("\n");

            }



            HtmlHeaders = ExpandRelativeUrls(extracted.ToString());

        }



        public string Preview(string title, string text)

        {

            EnsureHtmlHeadersLoaded();



            string result = HttpPost(

                new[,]

                {

                    { "action", "parse" },

                    { "prop", "text" }

                },

                new[,]

                {

                    { "title", title },

                    { "text", text },

                    { "disablepp", null }

                });



            CheckForErrors(result, "parse");

            try

            {

                XmlReader xr = XmlReader.Create(new StringReader(result));

                if (!xr.ReadToFollowing("text")) throw new Exception("Cannot find <text> element");

                return ExpandRelativeUrls(xr.ReadString());

            }

            catch (Exception ex)

            {

                throw new BrokenXmlException(this, ex);

            }

        }



        public void Rollback(string title, string user)

        {

            string result = HttpGet(

                new[,]

                    {

                        { "action", "query" },

                        { "prop", "revisions" },

                        { "rvtoken", "rollback" },

                        { "titles", title },



                    },

                    ActionOptions.All);



            CheckForErrors(result, "query");



            XmlReader xr = XmlReader.Create(new StringReader(result));

            if (!xr.ReadToFollowing("page")) throw new Exception("Cannot find <page> element");

            string rollbackToken = xr.GetAttribute("rollbacktoken");



            result = HttpPost(

                new[,]

                    {

                        {"action", "rollback"}

                    },

                new[,]

                    {

                        {"title", title},

                        {"token", rollbackToken},

                    });



            CheckForErrors(result, "rollback");

        }



        public string ExpandTemplates(string title, string text)

        {

            string result = HttpPost(

                new[,]

                {

                    { "action", "expandtemplates" }

                },

                new[,]

                {

                    { "title", title },

                    { "text", text }

                });



            CheckForErrors(result, "expandtemplates");

            try

            {

                XmlReader xr = XmlReader.Create(new StringReader(result));

                if (!xr.ReadToFollowing("expandtemplates")) throw new Exception("Cannot find <expandtemplates> element");

                return xr.ReadString();

            }

            catch (Exception ex)

            {

                throw new BrokenXmlException(this, ex);

            }

        }

        #endregion



        #region Error handling



        /// <summary>

        /// Checks the XML returned by the server for error codes and throws an appropriate exception

        /// </summary>

        /// <param name="xml">Server output</param>

        private XmlDocument CheckForErrors(string xml)

        {

            return CheckForErrors(xml, null);

        }



        private static readonly Regex MaxLag = new Regex(@": (\d+) seconds lagged", RegexOptions.Compiled | RegexOptions.IgnoreCase);



        /// <summary>

        /// Checks the XML returned by the server for error codes and throws an appropriate exception

        /// </summary>

        /// <param name="xml">Server output</param>

        /// <param name="action">The action performed, null if don't check</param>

        private XmlDocument CheckForErrors(string xml, string action)

        {

            if (string.IsNullOrEmpty(xml)) throw new ApiBlankException(this);



            var doc = new XmlDocument();

            try

            {

                doc.Load(new StringReader(xml));

            }

            catch (XmlException xe)

            {

                Tools.WriteDebug("ApiEdit::CheckForErrors", xml);



                string postParams = "";

                if (lastPostParameters != null )

                {

                    int length = lastPostParameters.GetUpperBound(0);

                    for (int i = 0; i <= length; i++)

                    {

                        if (lastPostParameters[i, 0].Contains("password") || lastPostParameters[i, 0].Contains("token"))

                        {

                            lastPostParameters[i, 1] = "<removed>";

                        }



                    }

                    postParams = BuildQuery(lastPostParameters);

                }

                throw new ApiXmlException(this, xe, lastGetUrl, postParams, xml);

            }



            //TODO: can't figure out the best time for this check

            bool prevMessages = User.HasMessages;

            User.Update(doc);

            if (action != "login"

                && action != "userinfo"

                && NewMessageThrows

                && User.HasMessages

                && !prevMessages)

                throw new NewMessagesException(this);



            var errors = doc.GetElementsByTagName("error");



            if (errors.Count > 0)

            {

                var error = errors[0];

                string errorCode = error.Attributes["code"].Value;

                string errorMessage = error.Attributes["info"].Value;



                switch (errorCode.ToLower())

                {

                    case "maxlag": //guessing

                        int maxlag;

                        int.TryParse(MaxLag.Match(xml).Groups[1].Value, out maxlag);

                        throw new MaxlagException(this, maxlag, 10);

                    case "wrnotloggedin":

                        throw new LoggedOffException(this);

                    case "spamdetected":

                        throw new SpamlistException(this, errorMessage);

                        //case "confirmemail":

                        //

                    default:

                        if (errorCode.Contains("disabled"))

                        {

                            new FeatureDisabledException(this, errorCode, errorMessage);

                        }



                        throw new ApiErrorException(this, errorCode, errorMessage);

                }

            }



            if (string.IsNullOrEmpty(action)) return doc; // no action to check



            var api = doc["api"];

            if (api == null) return doc;



            //FIXME: Awful code is awful

            var page = api.GetElementsByTagName("page");

            if (page.Count > 0 && page[0].Attributes != null && page[0].Attributes["invalid"] != null && page[0].Attributes["invalid"].Value == "")

                throw new InvalidTitleException(this, page[0].Attributes["title"].Value);



            if (api.GetElementsByTagName("interwiki").Count > 0)

                throw new InterwikiException(this);



            var actionElement = api[action];



            if (actionElement == null) return doc; // or shall we explode?



            if (actionElement.HasAttribute("assert"))

            {

                string what = actionElement.GetAttribute("assert");

                if (what == "user")

                    throw new LoggedOffException(this);

                throw new AssertionFailedException(this, what);

            }



            if (actionElement.HasAttribute("spamblacklist"))

            {

                throw new SpamlistException(this, actionElement.GetAttribute("spamblacklist"));

            }



            if (actionElement.GetElementsByTagName("captcha").Count > 0)

            {

                throw new CaptchaException(this);

            }



            string result = actionElement.GetAttribute("result");

            if (!string.IsNullOrEmpty(result) && result != "Success")

            {

                throw new OperationFailedException(this, action, result, xml);

            }



            return doc;

        }



        #endregion



        #region Helpers



        /// <summary>

        /// 

        /// </summary>

        /// <param name="value"></param>

        /// <returns></returns>

        protected static string BoolToParam(bool value)

        {

            return value ? "1" : "0";

        }



        protected static string WatchOptionsToParam(WatchOptions watch)

        {

            // Here we provide options for both 1.16 and older versions

            switch (watch)

            {

                case WatchOptions.UsePreferences:

                    return "watchlist=preferences";

                case WatchOptions.Watch:

                    return "watchlist=watch&watch";

                case WatchOptions.Unwatch:

                    return "watchlist=unwatch&unwatch";

                default:

                    return "watchlist=nochange";

            }

        }



        /// <summary>

        /// For private use, static to avoid unneeded reinitialisation

        /// </summary>

        private static readonly System.Security.Cryptography.MD5 Md5Summer = System.Security.Cryptography.MD5.Create();



        /// <summary>

        /// 

        /// </summary>

        /// <param name="input"></param>

        /// <returns></returns>

        protected static string MD5(string input)

        {

            return MD5(Encoding.UTF8.GetBytes(input));

        }



        /// <summary>

        /// 

        /// </summary>

        /// <param name="input"></param>

        /// <returns></returns>

        protected static string MD5(byte[] input)

        {

            byte[] hash = Md5Summer.ComputeHash(input);



            StringBuilder sb = new StringBuilder(20);

            for (int i = 0; i < hash.Length; i++)

            {

                sb.Append(hash[i].ToString("x2"));

            }



            return sb.ToString();

        }



        #endregion

    }



    public enum WatchOptions

    {

        NoChange,

        UsePreferences,

        Watch,

        Unwatch

    }



    [Flags]

    public enum ActionOptions

    {

        None = 0,

        CheckMaxlag = 1,

        RequireLogin = 2,

        CheckNewMessages = 4,



        All = CheckMaxlag | RequireLogin | CheckNewMessages

    };

}