/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the OpenSim Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
using OpenSim.Framework;
using OpenSim.Framework.Servers;
using OpenSim.Framework.Communications;
using OpenSim.Framework.Communications.Cache;
using Nini.Config;

namespace OpenSim.ApplicationPlugins.Rest.Inventory
{
    public class Rest
    {
        internal static readonly log4net.ILog Log =
            log4net.LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        internal static bool DEBUG = Log.IsDebugEnabled;

        /// <summary>
        /// Supported authentication schemes
        /// </summary>

        public const string AS_BASIC                      = "Basic";           // simple user/password verification
        public const string AS_DIGEST                     = "Digest";          // password safe authentication

        /// Supported Digest algorithms

        public const string Digest_MD5                    = "MD5";             // assumed default if omitted
        public const string Digest_MD5Sess                = "MD5-sess";        // session-span - not good for REST?

        public const string Qop_Auth                      = "auth";            // authentication only
        public const string Qop_Int                       = "auth-int";        // TODO

        /// <summary>
        /// These values have a single value for the whole
        /// domain and lifetime of the plugin handler. We
        /// make them static for ease of reference within
        /// the assembly. These are initialized by the
        /// RestHandler class during start-up.
        /// </summary>

        internal static IRestHandler              Plugin            = null;
        internal static OpenSimBase               main              = null;
        internal static CommunicationsManager     Comms             = null;
        internal static IInventoryServices        InventoryServices = null;
        internal static IUserService              UserServices      = null;
        internal static IAvatarService            AvatarServices    = null;
        internal static IAssetCache               AssetServices     = null;
        internal static string                    Prefix            = null;
        internal static IConfig                   Config            = null;
        internal static string                    GodKey            = null;
        internal static bool                      Authenticate      = true;
        internal static bool                      Secure            = true;
        internal static bool                      ExtendedEscape    = true;
        internal static bool                      DumpAsset         = false;
        internal static bool                      Fill              = false;
        internal static bool                      FlushEnabled      = true;
        internal static string                    Realm             = "OpenSim REST";
        internal static string                    Scheme            = AS_BASIC;
        internal static int                       DumpLineSize      = 32; // Should be a multiple of 16 or (possibly) 4

        /// <summary>
        /// HTTP requires that status information be generated for PUT
        /// and POST opertaions. This is in support of that. The
        /// operation verb gets substituted into the first string,
        /// and the completion code is inserted into the tail. The
        /// strings are put here to encourage consistency.
        /// </summary>

        internal static string                    statusHead        = "<html><body><title>{0} status</title><break>";
        internal static string                    statusTail        = "</body></html>";

        internal static Dictionary<int,string> HttpStatusDesc;

        static Rest()
        {
            HttpStatusDesc = new Dictionary<int,string>();
            if (HttpStatusCodeArray.Length != HttpStatusDescArray.Length)
            {
                Log.ErrorFormat("{0} HTTP Status Code and Description arrays do not match");
                throw new Exception("HTTP Status array discrepancy");
            }

            // Repackage the data into something more tractable. The sparse
            // nature of HTTP return codes makes an array a bad choice.

            for (int i=0; i<HttpStatusCodeArray.Length; i++)
            {
                HttpStatusDesc.Add(HttpStatusCodeArray[i], HttpStatusDescArray[i]);
            }
        }

        internal static int CreationDate
        {
            get { return (int) (DateTime.UtcNow - new DateTime(1970, 1, 1)).TotalSeconds; }
        }

        internal static string MsgId
        {
            get { return Plugin.MsgId; }
        }

        internal static string RequestId
        {
            get { return Plugin.RequestId; }
        }

        internal static Encoding Encoding = Encoding.UTF8;

        /// <summary>
        /// Version control for REST implementation. This
        /// refers to the overall infrastructure represented
        /// by the following classes
        ///     RequestData
        ///     RequestInventoryPlugin
        ///     Rest
        /// It does no describe implementation classes such as
        /// RestInventoryServices, which may morph much more
        /// often. Such classes ARE dependent upon this however
        /// and should check it in their Initialize method.
        /// </summary>

        public static readonly float Version  = 1.0F;
        public const  string  Name            = "REST 1.0";

        /// <summary>
        /// Currently defined HTTP methods.
        /// Only GET and HEAD are required to be
        /// supported by all servers. See Respond
        /// to see how these are handled.
        /// </summary>

        // REST AGENT 1.0 interpretations
        public const string GET     = "get";       // information retrieval - server state unchanged
        public const string HEAD    = "head";      // same as get except only the headers are returned.
        public const string POST    = "post";      // Replace the URI designated resource with the entity.
        public const string PUT     = "put";       // Add the entity to the context represented by the URI
        public const string DELETE  = "delete";    // Remove the URI designated resource from the server.

        public const string OPTIONS = "options";  //
        public const string TRACE   = "trace";    //
        public const string CONNECT = "connect";  //

        // Define this in one place...

        public const string UrlPathSeparator   = "/";
        public const string UrlMethodSeparator = ":";

        // Redirection qualifications

        public const bool PERMANENT = false;
        public const bool TEMPORARY = true;

        // Constant arrays used by String.Split

        public   static   readonly char   C_SPACE    = ' ';
        public   static   readonly char   C_SLASH    = '/';
        public   static   readonly char   C_PATHSEP  = '/';
        public   static   readonly char   C_COLON    = ':';
        public   static   readonly char   C_PLUS     = '+';
        public   static   readonly char   C_PERIOD   = '.';
        public   static   readonly char   C_COMMA    = ',';
        public   static   readonly char   C_DQUOTE   = '"';

        public   static   readonly string   CS_SPACE    = " ";
        public   static   readonly string   CS_SLASH    = "/";
        public   static   readonly string   CS_PATHSEP  = "/";
        public   static   readonly string   CS_COLON    = ":";
        public   static   readonly string   CS_PLUS     = "+";
        public   static   readonly string   CS_PERIOD   = ".";
        public   static   readonly string   CS_COMMA    = ",";
        public   static   readonly string   CS_DQUOTE   = "\"";

        public   static   readonly char[] CA_SPACE   = { C_SPACE   };
        public   static   readonly char[] CA_SLASH   = { C_SLASH   };
        public   static   readonly char[] CA_PATHSEP = { C_PATHSEP };
        public   static   readonly char[] CA_COLON   = { C_COLON   };
        public   static   readonly char[] CA_PERIOD  = { C_PERIOD  };
        public   static   readonly char[] CA_PLUS    = { C_PLUS    };
        public   static   readonly char[] CA_COMMA   = { C_COMMA   };
        public   static   readonly char[] CA_DQUOTE  = { C_DQUOTE  };

        // HTTP Code Values (in value order)

        public const int HttpStatusCodeContinue           = 100;
        public const int HttpStatusCodeSwitchingProtocols = 101;

        public const int HttpStatusCodeOK                 = 200;
        public const int HttpStatusCodeCreated            = 201;
        public const int HttpStatusCodeAccepted           = 202;
        public const int HttpStatusCodeNonAuthoritative   = 203;
        public const int HttpStatusCodeNoContent          = 204;
        public const int HttpStatusCodeResetContent       = 205;
        public const int HttpStatusCodePartialContent     = 206;

        public const int HttpStatusCodeMultipleChoices    = 300;
        public const int HttpStatusCodePermanentRedirect  = 301;
        public const int HttpStatusCodeFound              = 302;
        public const int HttpStatusCodeSeeOther           = 303;
        public const int HttpStatusCodeNotModified        = 304;
        public const int HttpStatusCodeUseProxy           = 305;
        public const int HttpStatusCodeReserved306        = 306;
        public const int HttpStatusCodeTemporaryRedirect  = 307;

        public const int HttpStatusCodeBadRequest         = 400;
        public const int HttpStatusCodeNotAuthorized      = 401;
        public const int HttpStatusCodePaymentRequired    = 402;
        public const int HttpStatusCodeForbidden          = 403;
        public const int HttpStatusCodeNotFound           = 404;
        public const int HttpStatusCodeMethodNotAllowed   = 405;
        public const int HttpStatusCodeNotAcceptable      = 406;
        public const int HttpStatusCodeProxyAuthenticate  = 407;
        public const int HttpStatusCodeTimeOut            = 408;
        public const int HttpStatusCodeConflict           = 409;
        public const int HttpStatusCodeGone               = 410;
        public const int HttpStatusCodeLengthRequired     = 411;
        public const int HttpStatusCodePreconditionFailed = 412;
        public const int HttpStatusCodeEntityTooLarge     = 413;
        public const int HttpStatusCodeUriTooLarge        = 414;
        public const int HttpStatusCodeUnsupportedMedia   = 415;
        public const int HttpStatusCodeRangeNotSatsified  = 416;
        public const int HttpStatusCodeExpectationFailed  = 417;

        public const int HttpStatusCodeServerError        = 500;
        public const int HttpStatusCodeNotImplemented     = 501;
        public const int HttpStatusCodeBadGateway         = 502;
        public const int HttpStatusCodeServiceUnavailable = 503;
        public const int HttpStatusCodeGatewayTimeout     = 504;
        public const int HttpStatusCodeHttpVersionError   = 505;

        public static readonly int[] HttpStatusCodeArray  = {
            HttpStatusCodeContinue,
            HttpStatusCodeSwitchingProtocols,
            HttpStatusCodeOK,
            HttpStatusCodeCreated,
            HttpStatusCodeAccepted,
            HttpStatusCodeNonAuthoritative,
            HttpStatusCodeNoContent,
            HttpStatusCodeResetContent,
            HttpStatusCodePartialContent,
            HttpStatusCodeMultipleChoices,
            HttpStatusCodePermanentRedirect,
            HttpStatusCodeFound,
            HttpStatusCodeSeeOther,
            HttpStatusCodeNotModified,
            HttpStatusCodeUseProxy,
            HttpStatusCodeReserved306,
            HttpStatusCodeTemporaryRedirect,
            HttpStatusCodeBadRequest,
            HttpStatusCodeNotAuthorized,
            HttpStatusCodePaymentRequired,
            HttpStatusCodeForbidden,
            HttpStatusCodeNotFound,
            HttpStatusCodeMethodNotAllowed,
            HttpStatusCodeNotAcceptable,
            HttpStatusCodeProxyAuthenticate,
            HttpStatusCodeTimeOut,
            HttpStatusCodeConflict,
            HttpStatusCodeGone,
            HttpStatusCodeLengthRequired,
            HttpStatusCodePreconditionFailed,
            HttpStatusCodeEntityTooLarge,
            HttpStatusCodeUriTooLarge,
            HttpStatusCodeUnsupportedMedia,
            HttpStatusCodeRangeNotSatsified,
            HttpStatusCodeExpectationFailed,
            HttpStatusCodeServerError,
            HttpStatusCodeNotImplemented,
            HttpStatusCodeBadGateway,
            HttpStatusCodeServiceUnavailable,
            HttpStatusCodeGatewayTimeout,
            HttpStatusCodeHttpVersionError
        };

        // HTTP Status Descriptions (in status code order)
        // This array must be kept strictly consistent with respect
        // to the status code array above.

        public static readonly string[] HttpStatusDescArray  = {
            "Continue Request",
            "Switching Protocols",
            "OK",
            "CREATED",
            "ACCEPTED",
            "NON-AUTHORITATIVE INFORMATION",
            "NO CONTENT",
            "RESET CONTENT",
            "PARTIAL CONTENT",
            "MULTIPLE CHOICES",
            "PERMANENT REDIRECT",
            "FOUND",
            "SEE OTHER",
            "NOT MODIFIED",
            "USE PROXY",
            "RESERVED CODE 306",
            "TEMPORARY REDIRECT",
            "BAD REQUEST",
            "NOT AUTHORIZED",
            "PAYMENT REQUIRED",
            "FORBIDDEN",
            "NOT FOUND",
            "METHOD NOT ALLOWED",
            "NOT ACCEPTABLE",
            "PROXY AUTHENTICATION REQUIRED",
            "TIMEOUT",
            "CONFLICT",
            "GONE",
            "LENGTH REQUIRED",
            "PRECONDITION FAILED",
            "ENTITY TOO LARGE",
            "URI TOO LARGE",
            "UNSUPPORTED MEDIA",
            "RANGE NOT SATISFIED",
            "EXPECTATION FAILED",
            "SERVER ERROR",
            "NOT IMPLEMENTED",
            "BAD GATEWAY",
            "SERVICE UNAVAILABLE",
            "GATEWAY TIMEOUT",
            "HTTP VERSION NOT SUPPORTED"
        };

        // HTTP Headers

        public const string HttpHeaderAccept              = "Accept";
        public const string HttpHeaderAcceptCharset       = "Accept-Charset";
        public const string HttpHeaderAcceptEncoding      = "Accept-Encoding";
        public const string HttpHeaderAcceptLanguage      = "Accept-Language";
        public const string HttpHeaderAcceptRanges        = "Accept-Ranges";
        public const string HttpHeaderAge                 = "Age";
        public const string HttpHeaderAllow               = "Allow";
        public const string HttpHeaderAuthorization       = "Authorization";
        public const string HttpHeaderCacheControl        = "Cache-Control";
        public const string HttpHeaderConnection          = "Connection";
        public const string HttpHeaderContentEncoding     = "Content-Encoding";
        public const string HttpHeaderContentLanguage     = "Content-Language";
        public const string HttpHeaderContentLength       = "Content-Length";
        public const string HttpHeaderContentLocation     = "Content-Location";
        public const string HttpHeaderContentMD5          = "Content-MD5";
        public const string HttpHeaderContentRange        = "Content-Range";
        public const string HttpHeaderContentType         = "Content-Type";
        public const string HttpHeaderDate                = "Date";
        public const string HttpHeaderETag                = "ETag";
        public const string HttpHeaderExpect              = "Expect";
        public const string HttpHeaderExpires             = "Expires";
        public const string HttpHeaderFrom                = "From";
        public const string HttpHeaderHost                = "Host";
        public const string HttpHeaderIfMatch             = "If-Match";
        public const string HttpHeaderIfModifiedSince     = "If-Modified-Since";
        public const string HttpHeaderIfNoneMatch         = "If-None-Match";
        public const string HttpHeaderIfRange             = "If-Range";
        public const string HttpHeaderIfUnmodifiedSince   = "If-Unmodified-Since";
        public const string HttpHeaderLastModified        = "Last-Modified";
        public const string HttpHeaderLocation            = "Location";
        public const string HttpHeaderMaxForwards         = "Max-Forwards";
        public const string HttpHeaderPragma              = "Pragma";
        public const string HttpHeaderProxyAuthenticate   = "Proxy-Authenticate";
        public const string HttpHeaderProxyAuthorization  = "Proxy-Authorization";
        public const string HttpHeaderRange               = "Range";
        public const string HttpHeaderReferer             = "Referer";
        public const string HttpHeaderRetryAfter          = "Retry-After";
        public const string HttpHeaderServer              = "Server";
        public const string HttpHeaderTE                  = "TE";
        public const string HttpHeaderTrailer             = "Trailer";
        public const string HttpHeaderTransferEncoding    = "Transfer-Encoding";
        public const string HttpHeaderUpgrade             = "Upgrade";
        public const string HttpHeaderUserAgent           = "User-Agent";
        public const string HttpHeaderVary                = "Vary";
        public const string HttpHeaderVia                 = "Via";
        public const string HttpHeaderWarning             = "Warning";
        public const string HttpHeaderWWWAuthenticate     = "WWW-Authenticate";

        /// Utility routines

        public static string StringToBase64(string str)
        {
            try
            {
                byte[] encData_byte = new byte[str.Length];
                encData_byte = Encoding.UTF8.GetBytes(str);
                return Convert.ToBase64String(encData_byte);
            }
            catch
            {
                return String.Empty;
            }
        }

        public static string Base64ToString(string str)
        {
            UTF8Encoding encoder = new UTF8Encoding();
            Decoder utf8Decode = encoder.GetDecoder();
            try
            {
                byte[] todecode_byte = Convert.FromBase64String(str);
                int charCount = utf8Decode.GetCharCount(todecode_byte, 0, todecode_byte.Length);
                char[] decoded_char = new char[charCount];
                utf8Decode.GetChars(todecode_byte, 0, todecode_byte.Length, decoded_char, 0);
                return new String(decoded_char);
            }
            catch
            {
                return String.Empty;
            }
        }

        private const string hvals = "0123456789abcdef";

        public static int Hex2Int(string hex)
        {
            int    val = 0;
            int    sum = 0;
            string tmp = null;

            if (hex != null)
            {
                tmp = hex.ToLower();
                for (int i = 0; i < tmp.Length; i++)
                {
                    val = hvals.IndexOf(tmp[i]);
                    if (val == -1)
                        break;
                    sum *= 16;
                    sum += val;
                }
            }

            return sum;
        }

        // Nonce management

        public static string NonceGenerator()
        {
            return StringToBase64(CreationDate + Guid.NewGuid().ToString());
        }

        // Dump the specified data stream

        public static void Dump(byte[] data)
        {
            char[] buffer = new char[Rest.DumpLineSize];
            int cc = 0;

            for (int i = 0; i < data.Length; i++)
            {
                if (i % Rest.DumpLineSize == 0) Console.Write("\n{0}: ",i.ToString("d8"));

                if (i % 4  == 0) Console.Write(" ");

                Console.Write("{0}",data[i].ToString("x2"));

                if (data[i] < 127 && data[i] > 31)
                    buffer[i % Rest.DumpLineSize] = (char) data[i];
                else
                    buffer[i % Rest.DumpLineSize] = '.';

                cc++;

                if (i != 0 && (i + 1) % Rest.DumpLineSize == 0)
                {
                    Console.Write(" |"+(new String(buffer))+"|");
                    cc = 0;
                }
            }

            // Finish off any incomplete line

            if (cc != 0)
            {
                for (int i = cc ; i < Rest.DumpLineSize; i++)
                {
                    if (i % 4  == 0) Console.Write(" ");
                    Console.Write("  ");
                    buffer[i % Rest.DumpLineSize] = ' ';
                }
                Console.WriteLine(" |"+(new String(buffer))+"|");
            }
            else
            {
                Console.Write("\n");
            }
        }
    }

    // Local exception type

    public class RestException : Exception
    {
        internal int    statusCode;
        internal string statusDesc;
        internal string httpmethod;
        internal string httppath;

        public RestException(string msg) : base(msg)
        {
        }
    }
}