using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Esiur.Misc;
using Esiur.Data;
 
namespace Esiur.Net.Packets
{
    public class HTTPResponsePacket : Packet
    {

        public enum ComposeOptions : int
        {
            AllCalculateLength,
            AllDontCalculateLength,
            SpecifiedHeadersOnly,
            DataOnly
        }

        public enum ResponseCode : int
        {
            HTTP_SWITCHING = 101,
            HTTP_OK = 200,
            HTTP_NOTFOUND = 404,
            HTTP_SERVERERROR = 500,
            HTTP_MOVED = 301,
            HTTP_NOTMODIFIED = 304,
            HTTP_REDIRECT = 307
        }

        public class HTTPCookie
        {
            public string Name;
            public string Value;
            public DateTime Expires;
            public string Path;
            public bool HttpOnly;
            public string Domain;
            
            public HTTPCookie(string Name, string Value)
            {
                this.Name = Name;
                this.Value = Value;
            }

            public HTTPCookie(string Name, string Value, DateTime Expires)
            {
                this.Name = Name;
                this.Value = Value;
                this.Expires = Expires;
            }

            public override string ToString()
            {
                //Set-Cookie: ckGeneric=CookieBody; expires=Sun, 30-Dec-2001 21:00:00 GMT; domain=.com.au; path=/
                //Set-Cookie: SessionID=another; expires=Fri, 29 Jun 2006 20:47:11 UTC; path=/
                string Cookie = Name + "=" + Value;

                if (Expires.Ticks != 0)
                {
                    Cookie += "; expires=" + Expires.ToUniversalTime().ToString("ddd, dd MMM yyyy HH:mm:ss") + " GMT";
                }

                if (Domain != null)
                {
                    Cookie += "; domain=" + Domain;
                }

                if (Path != null)
                {
                    Cookie += "; path=" + Path;
                }

                if (HttpOnly)
                {
                    Cookie += "; HttpOnly";
                }

                return Cookie;
            }
        }

        public StringKeyList Headers = new StringKeyList(true);
        public string Version = "HTTP/1.1";

        public byte[] Message;
        public ResponseCode Number;
        public string Text;
        //public DStringDictionary Cookies;
        public List<HTTPCookie> Cookies = new List<HTTPCookie>();
        public bool Handled;
        //public bool ResponseHandled; //flag this as true if you are handling it yourself

        //private bool createSession;

        //private HTTPServer Server;
        //public HTTPSession Session;

        public override string ToString()
        {
            return "HTTPResponsePacket"
                + "\n\tVersion: " + Version
                //+ "\n\tMethod: " + Method
                //+ "\n\tURL: " + URL
                + "\n\tMessage: " + (Message != null ? Message.Length.ToString() : "NULL");
        }

        private string MakeHeader(ComposeOptions Options)
        {
            string header = Version + " " + (int)Number + " " + Text + "\r\n"
                              + "Server: Delta Web Server\r\n"
                //Fri, 30 Oct 2007 14:19:41 GMT"
                              + "Date: " + DateTime.Now.ToUniversalTime().ToString("r") + "\r\n";


            if (Options == ComposeOptions.AllCalculateLength && Message != null) 
            {
                Headers["Content-Length"] = Message.Length.ToString();
            }

            foreach (var kv in Headers)
            {
                header += kv.Key + ": " + kv.Value + "\r\n";
            }

            // Set-Cookie: ckGeneric=CookieBody; expires=Sun, 30-Dec-2007 21:00:00 GMT; path=/
            // Set-Cookie: ASPSESSIONIDQABBDSQA=IPDPMMMALDGFLMICEJIOCIPM; path=/
            
            foreach (var Cookie in Cookies)
            {
                header += "Set-Cookie: " + Cookie.ToString() + "\r\n";
            }


            header += "\r\n";

            return header;
        }


        public bool Compose(ComposeOptions options)
        {
            List<byte> msg = new List<byte>();

            if (options != ComposeOptions.DataOnly)
            {
                msg.AddRange(Encoding.UTF8.GetBytes(MakeHeader(options)));
            }

            if (options != ComposeOptions.SpecifiedHeadersOnly)
            {
                if (Message != null)
                   msg.AddRange(Message);
            }           
            
            Data = msg.ToArray();

            return true;
        }

        public override bool Compose()
        {
            return Compose(ComposeOptions.AllDontCalculateLength);
        }

        public override long Parse(byte[] data, uint offset, uint ends)
        {
            string[] sMethod = null;
            string[] sLines = null;

            uint headerSize = 0;

            for (uint i = offset; i < ends - 3; i++)
            {
                if (data[i] == '\r' && data[i + 1] == '\n'
                    && data[i + 2] == '\r' && data[i + 3] == '\n')
                {
                    sLines = Encoding.ASCII.GetString(data, (int)offset, (int)(i - offset)).Split(new string[] { "\r\n" },
                        StringSplitOptions.None);

                    headerSize = i + 4;
                    break;
                }
            }

            if (headerSize == 0)
                return -1;

            //Cookies = new DStringDictionary();
            //Headers = new DStringDictionary(true);

            sMethod = sLines[0].Split(' ');

            if (sMethod.Length == 3)
            {
                Version = sMethod[0].Trim();
                Number = (ResponseCode)(Convert.ToInt32(sMethod[1].Trim()));
                Text = sMethod[2];
            }

            // Read all headers

            for (int i = 1; i < sLines.Length; i++)
            {
                if (sLines[i] == String.Empty)
                {
                    // Invalid header
                    return 0;
                }

                if (sLines[i].IndexOf(':') == -1)
                {
                    // Invalid header
                    return 0;
                }

                string[] header = sLines[i].Split(new char[] { ':' }, 2);

                header[0] = header[0].ToLower();
                Headers[header[0]] = header[1].Trim();

                //Set-Cookie: NAME=VALUE; expires=DATE;

                if (header[0] == "set-cookie")
                {
                    string[] cookie = header[1].Split(';');

                    if (cookie.Length >= 1)
                    {
                        string[] splitCookie = cookie[0].Split('=');
                        HTTPCookie c = new HTTPCookie(splitCookie[0], splitCookie[1]);

                        for (int j = 1; j < cookie.Length; j++)
                        {
                            splitCookie = cookie[j].Split('=');
                            switch (splitCookie[0].ToLower())
                            {
                                case "domain":
                                    c.Domain = splitCookie[1];
                                    break;
                                case "path":
                                    c.Path = splitCookie[1];
                                    break;
                                case "httponly":
                                    c.HttpOnly = true;
                                    break;
                                case "expires":
                                    // Wed, 13-Jan-2021 22:23:01 GMT
                                    c.Expires = DateTime.Parse(splitCookie[1]);
                                    break;
                            }
                        }

                    }

                }
            }

            // Content-Length

            try
            {

                uint contentLength = uint.Parse((string)Headers["content-length"]);

                // check limit
                if (contentLength > data.Length - headerSize)
                {
                    return contentLength - (data.Length - headerSize);
                }

                Message = DC.Clip(data, offset, contentLength);

                return headerSize + contentLength;

            }
            catch
            {
                return 0;
            }
        }
    }
}