using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.IO;
using System.Web;

public class WebServer
{
   public static void Main()
   {
      IPEndPoint ipep = new IPEndPoint(IPAddress.Any, 8080);

      Socket newsock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

      newsock.Bind(ipep);
      newsock.Listen(10);
  
      while(true)
      {
   Socket client = newsock.Accept();
   IPEndPoint clientep = (IPEndPoint) client.RemoteEndPoint;
        
         // create a new thread and then receive message.
         HttpListener listener = new HttpListener(client);
         Thread thread = new Thread(new ThreadStart(listener.run));
         thread.Start();
      }
   }
}

class HttpListener
{
    String[] map ={"mpeg=video/mpeg", "mpg=video/mpeg", "wav=audio/x-wav", "jpg=image/jpeg", "gif=image/gif", "zip=application/zip", "pdf=application/pdf", "xls=application/vnd.ms-excel", "ppt=application/vnd.ms-powerpoint", "doc=application/msword", "htm=text/html", "html=text/html", "css=text/plain", "vbs=text/plain", "js=text/plain", "txt=text/plain", "java=text/plain"};
    Socket socket;
    NetworkStream stream;
    String header;
    String root = ".";

    public HttpListener(Socket s)
    {
        socket = s;
    }

    public void run()
    {
     stream = new NetworkStream(socket);
        request();
        response();
        stream.Close();
    }

    public void send(String str) {
        socket.Send(Encoding.UTF8.GetBytes(str));
    }

    public static String innerText(String pText, String beginMark, String endMark)
    {
        int beginStart = pText.IndexOf(beginMark);
        if (beginStart < 0) return null;
        int beginEnd = beginStart + beginMark.Length;
        int endStart = pText.IndexOf(endMark, beginEnd);
        if (endStart < 0) return null;
        return pText.Substring(beginEnd, endStart - beginEnd);
    }

    public void request()
    {
        StreamReader reader = new StreamReader(stream);
        header = "";
        while (true)
        {
            String line = reader.ReadLine();
            Console.WriteLine(line);
            if (line.Trim().Length == 0)
                break;
            header += line + "\n";
        }
    }
   
    void response()
    {
      try
      {
        Console.WriteLine("========response()==========");
        String path = innerText(header, "GET ", "HTTP/").Trim(); // 取得檔案路徑 : GET 版。
        HttpUtility.UrlDecode(path);
        String fullPath = root+path;
        FileInfo info = new FileInfo(fullPath);
        if (!info.Exists)
            throw new Exception("File not found !");
        send("HTTP/1.0 200 OK\n");
        send("Content-Type: "+type(fullPath)+"\n");
        send("Content-Length: "+info.Length+"\n");
        send("\n");
        byte[] buffer = new byte[4096];
        FileStream fileStream = File.OpenRead(fullPath);
        while (true)
        {
            int len = fileStream.Read(buffer, 0, buffer.Length);
            socket.Send(buffer, 0, len, SocketFlags.None);
            if (len < buffer.Length) break;
        }
        fileStream.Close();
      } catch {
        send("HTTP/1.0 404 Error\n");
        send("\n");
      }
    }

    String type(String path)
    {
        String type = "*/*";
        path = path.ToLower();
        for (int i = 0; i < map.Length; i++)
        {
            String[] tokens = map[i].Split('=');
            String ext = tokens[0], mime = tokens[1];
            if (path.EndsWith("." + ext)) type = mime;
        }
        return type;
    }
}