//
// HttpListenerResponse.cs
//	Copied from System.Net.HttpListenerResponse.cs
//
// Author:
//	Gonzalo Paniagua Javier (gonzalo@novell.com)
//
// Copyright (c) 2005 Novell, Inc. (http://www.novell.com)
// Copyright (c) 2012 sta.blockhead (sta.blockhead@gmail.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.Globalization;
using System.IO;
using System.Net;
using System.Text;

namespace WebSocketSharp.Net
{
    public sealed class HttpListenerResponse : IDisposable
    {
        #region Private Fields

        bool chunked;
        bool cl_set;
        Encoding content_encoding;
        long content_length;
        string content_type;
        HttpListenerContext context;
        CookieCollection cookies;
        bool disposed;
        bool force_close_chunked;
        WebHeaderCollection headers;
        bool keep_alive;
        string location;
        ResponseStream output_stream;
        int status_code;
        string status_description;
        Version version;

        #endregion

        #region Internal Fields

        internal bool HeadersSent;

        #endregion

        #region Constructor

        internal HttpListenerResponse(HttpListenerContext context)
        {
            this.context = context;
            Init();
        }

        #endregion

        #region Internal Property

        internal bool ForceCloseChunked
        {
            get { return force_close_chunked; }
        }

        #endregion

        #region Public Properties

        public Encoding ContentEncoding
        {
            get
            {
                if (content_encoding == null)
                    content_encoding = Encoding.Default;
                return content_encoding;
            }
            set
            {
                if (disposed)
                    throw new ObjectDisposedException(GetType().ToString());

                // TODO: is null ok?
                if (HeadersSent)
                    throw new InvalidOperationException("Cannot be changed after headers are sent.");

                content_encoding = value;
            }
        }

        public long ContentLength64
        {
            get { return content_length; }
            set
            {
                if (disposed)
                    throw new ObjectDisposedException(GetType().ToString());

                if (HeadersSent)
                    throw new InvalidOperationException("Cannot be changed after headers are sent.");

                if (value < 0)
                    throw new ArgumentOutOfRangeException("Must be >= 0", "value");

                cl_set = true;
                content_length = value;
            }
        }

        public string ContentType
        {
            get { return content_type; }
            set
            {
                // TODO: is null ok?
                if (disposed)
                    throw new ObjectDisposedException(GetType().ToString());

                if (HeadersSent)
                    throw new InvalidOperationException("Cannot be changed after headers are sent.");

                content_type = value;
            }
        }

        // RFC 2109, 2965 + the netscape specification at http://wp.netscape.com/newsref/std/cookie_spec.html
        public CookieCollection Cookies
        {
            get
            {
                if (cookies == null)
                    cookies = new CookieCollection();
                return cookies;
            }
            set { cookies = value; } // null allowed?
        }

        public WebHeaderCollection Headers
        {
            get { return headers; }
            set
            {
                /**
                 *	"If you attempt to set a Content-Length, Keep-Alive, Transfer-Encoding, or
                 *	WWW-Authenticate header using the Headers property, an exception will be
                 *	thrown. Use the KeepAlive or ContentLength64 properties to set these headers.
                 *	You cannot set the Transfer-Encoding or WWW-Authenticate headers manually."
                */
                // TODO: check if this is marked readonly after headers are sent.
                headers = value;
            }
        }

        public bool KeepAlive
        {
            get { return keep_alive; }
            set
            {
                if (disposed)
                    throw new ObjectDisposedException(GetType().ToString());

                if (HeadersSent)
                    throw new InvalidOperationException("Cannot be changed after headers are sent.");

                keep_alive = value;
            }
        }

        public Stream OutputStream
        {
            get
            {
                if (output_stream == null)
                    output_stream = context.Connection.GetResponseStream();
                return output_stream;
            }
        }

        public Version ProtocolVersion
        {
            get { return version; }
            set
            {
                if (disposed)
                    throw new ObjectDisposedException(GetType().ToString());

                if (HeadersSent)
                    throw new InvalidOperationException("Cannot be changed after headers are sent.");

                if (value == null)
                    throw new ArgumentNullException("value");

                if (value.Major != 1 || (value.Minor != 0 && value.Minor != 1))
                    throw new ArgumentException("Must be 1.0 or 1.1", "value");

                if (disposed)
                    throw new ObjectDisposedException(GetType().ToString());

                version = value;
            }
        }

        public string RedirectLocation
        {
            get { return location; }
            set
            {
                if (disposed)
                    throw new ObjectDisposedException(GetType().ToString());

                if (HeadersSent)
                    throw new InvalidOperationException("Cannot be changed after headers are sent.");

                location = value;
            }
        }

        public bool SendChunked
        {
            get { return chunked; }
            set
            {
                if (disposed)
                    throw new ObjectDisposedException(GetType().ToString());

                if (HeadersSent)
                    throw new InvalidOperationException("Cannot be changed after headers are sent.");

                chunked = value;
            }
        }

        public int StatusCode
        {
            get { return status_code; }
            set
            {
                if (disposed)
                    throw new ObjectDisposedException(GetType().ToString());

                if (HeadersSent)
                    throw new InvalidOperationException("Cannot be changed after headers are sent.");

                if (value < 100 || value > 999)
                    throw new ProtocolViolationException("StatusCode must be between 100 and 999.");

                status_code = value;
                status_description = Ext.GetStatusDescription(value);
            }
        }

        public string StatusDescription
        {
            get { return status_description; }
            set
            {
                status_description = value;
            }
        }

        #endregion

        #region Private Methods

        void Close(bool force)
        {
            disposed = true;
            context.Connection.Close(force);
        }

        void IDisposable.Dispose()
        {
            Close(true); // TODO: Abort or Close?
        }

        bool FindCookie(Cookie cookie)
        {
            string name = cookie.Name;
            string domain = cookie.Domain;
            string path = cookie.Path;
            foreach (Cookie c in cookies)
            {
                if (name != c.Name)
                    continue;
                if (domain != c.Domain)
                    continue;
                if (path == c.Path)
                    return true;
            }

            return false;
        }

        void Init()
        {
            headers = new WebHeaderCollection();
            keep_alive = true;
            status_code = 200;
            status_description = "OK";
            version = HttpVersion.Version11;
        }

        #endregion

        #region Internal Method

        internal void SendHeaders(bool closing, MemoryStream ms)
        {
            Encoding encoding = content_encoding;
            if (encoding == null)
                encoding = Encoding.Default;

            if (content_type != null)
            {
                if (content_encoding != null && content_type.IndexOf("charset=", StringComparison.Ordinal) == -1)
                {
                    string enc_name = content_encoding.WebName;
                    headers.SetInternal("Content-Type", content_type + "; charset=" + enc_name);
                }
                else
                {
                    headers.SetInternal("Content-Type", content_type);
                }
            }

            if (headers["Server"] == null)
                headers.SetInternal("Server", "Mono-HTTPAPI/1.0");

            CultureInfo inv = CultureInfo.InvariantCulture;
            if (headers["Date"] == null)
                headers.SetInternal("Date", DateTime.UtcNow.ToString("r", inv));

            if (!chunked)
            {
                if (!cl_set && closing)
                {
                    cl_set = true;
                    content_length = 0;
                }

                if (cl_set)
                    headers.SetInternal("Content-Length", content_length.ToString(inv));
            }

            Version v = context.Request.ProtocolVersion;
            if (!cl_set && !chunked && v >= HttpVersion.Version11)
                chunked = true;

            /* Apache forces closing the connection for these status codes:
             *	HttpStatusCode.BadRequest 				400
             *	HttpStatusCode.RequestTimeout 			408
             *	HttpStatusCode.LengthRequired 			411
             *	HttpStatusCode.RequestEntityTooLarge 	413
             *	HttpStatusCode.RequestUriTooLong 		414
             *	HttpStatusCode.InternalServerError 		500
             *	HttpStatusCode.ServiceUnavailable 		503
             */
            bool conn_close = (status_code == 400 || status_code == 408 || status_code == 411 ||
                    status_code == 413 || status_code == 414 || status_code == 500 ||
                    status_code == 503);

            if (conn_close == false)
                conn_close = !context.Request.KeepAlive;

            // They sent both KeepAlive: true and Connection: close!?
            if (!keep_alive || conn_close)
            {
                headers.SetInternal("Connection", "close");
                conn_close = true;
            }

            if (chunked)
                headers.SetInternal("Transfer-Encoding", "chunked");

            int reuses = context.Connection.Reuses;
            if (reuses >= 100)
            {
                force_close_chunked = true;
                if (!conn_close)
                {
                    headers.SetInternal("Connection", "close");
                    conn_close = true;
                }
            }

            if (!conn_close)
            {
                headers.SetInternal("Keep-Alive", String.Format("timeout=15,max={0}", 100 - reuses));
                if (context.Request.ProtocolVersion <= HttpVersion.Version10)
                    headers.SetInternal("Connection", "keep-alive");
            }

            if (location != null)
                headers.SetInternal("Location", location);

            if (cookies != null)
            {
                foreach (Cookie cookie in cookies)
                    headers.SetInternal("Set-Cookie", cookie.ToClientString());
            }

            StreamWriter writer = new StreamWriter(ms, encoding, 256);
            writer.Write("HTTP/{0} {1} {2}\r\n", version, status_code, status_description);
            string headers_str = headers.ToStringMultiValue();
            writer.Write(headers_str);
            writer.Flush();
            int preamble = (encoding.CodePage == 65001) ? 3 : encoding.GetPreamble().Length;
            if (output_stream == null)
                output_stream = context.Connection.GetResponseStream();

            /* Assumes that the ms was at position 0 */
            ms.Position = preamble;
            HeadersSent = true;
        }

        #endregion

        #region Public Methods

        public void Abort()
        {
            if (disposed)
                return;

            Close(true);
        }

        public void AddHeader(string name, string value)
        {
            if (name == null)
                throw new ArgumentNullException("name");

            if (name == "")
                throw new ArgumentException("'name' cannot be empty", "name");

            // TODO: check for forbidden headers and invalid characters
            if (value.Length > 65535)
                throw new ArgumentOutOfRangeException("value");

            headers.Set(name, value);
        }

        public void AppendCookie(Cookie cookie)
        {
            if (cookie == null)
                throw new ArgumentNullException("cookie");

            Cookies.Add(cookie);
        }

        public void AppendHeader(string name, string value)
        {
            if (name == null)
                throw new ArgumentNullException("name");

            if (name == "")
                throw new ArgumentException("'name' cannot be empty", "name");

            if (value.Length > 65535)
                throw new ArgumentOutOfRangeException("value");

            headers.Add(name, value);
        }

        public void Close()
        {
            if (disposed)
                return;

            Close(false);
        }

        public void Close(byte[] responseEntity, bool willBlock)
        {
            if (disposed)
                return;

            if (responseEntity == null)
                throw new ArgumentNullException("responseEntity");

            // TODO: if willBlock -> BeginWrite + Close ?
            ContentLength64 = responseEntity.Length;
            OutputStream.Write(responseEntity, 0, (int)content_length);
            Close(false);
        }

        public void CopyFrom(HttpListenerResponse templateResponse)
        {
            headers.Clear();
            headers.Add(templateResponse.headers);
            content_length = templateResponse.content_length;
            status_code = templateResponse.status_code;
            status_description = templateResponse.status_description;
            keep_alive = templateResponse.keep_alive;
            version = templateResponse.version;
        }

        public void Redirect(string url)
        {
            StatusCode = 302; // Found
            location = url;
        }

        public void SetCookie(Cookie cookie)
        {
            if (cookie == null)
                throw new ArgumentNullException("cookie");

            if (cookies != null)
            {
                if (FindCookie(cookie))
                    throw new ArgumentException("The cookie already exists.");
            }
            else
            {
                cookies = new CookieCollection();
            }

            cookies.Add(cookie);
        }

        #endregion
    }
}