package com.example.httpserver;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class HttpServer {
  private static final Integer port = 80;//HTTP默認端口80

  public static void main(String[] args) {
    ServerSocket serverSocket;

    try {
      //建立服務器Socket,監聽客戶端請求
      serverSocket = new ServerSocket(port);
      System.out.println("Server is running on port:"+serverSocket.getLocalPort());
      //死循環不間斷監聽客戶端請求
      while(true){
        final Socket socket = serverSocket.accept();
        System.out.println("biuld a new tcp link with client,the cient address:"+ 
            socket.getInetAddress()+":"+socket.getPort());
        //并發處理HTTP客戶端請求
        service(socket);
      }
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  public static void service(Socket socket)
  {
    new Thread(){
      public void run(){
        InputStream inSocket;
        try {
          //獲取HTTP請求頭
          inSocket = socket.getInputStream();
          int size = inSocket.available();
          byte[] buffer = new byte[size];
          inSocket.read(buffer);
          String request = new String(buffer);
          System.out.println("ClientBrowser:\n"+request+"\n"
              + "------------------------------------------------------------------");

          String firstLineOfRequest = "";
          String[] heads;
          String uri = "/index.html";
          String contentType ="";
          if(request.length() > 0){
            firstLineOfRequest = request.substring(0,request.indexOf("\r\n"));
            heads = firstLineOfRequest.split(" ");
            uri = heads[1];

            if(uri.indexOf("html") != -1){
              contentType = "text/html";
            }else{
              contentType = "application/octet-stream";
            }
          }
          //將響應頭發送給客戶端
          String responseFirstLine = "HTTP/1.1 200 OK\r\n";

          String responseHead = "Content-Type:" + contentType +"\r\n";

          OutputStream outSocket = socket.getOutputStream();
          System.out.println("ServerResponse:\n"+responseFirstLine+"\n"+responseHead+"\n"
              + "--------------------------------------------------------------------");
          outSocket.write(responseFirstLine.getBytes());
          outSocket.write(responseHead.getBytes());
          //通過HTTP請求中的uri讀取相應文件發送給客戶端
          FileInputStream writehtml = new FileInputStream(new File("wwwroot"+uri));
          outSocket.write("\r\n".getBytes()); 
          byte[] htmlbuffer = new byte[writehtml.available()];
          if(writehtml !=null){
            int len = 0;
            System.out.println("writeHtml");
            while((len = writehtml.read(htmlbuffer)) != -1){
              outSocket.write(htmlbuffer, 0,len);
            }
          }
          outSocket.close();
          socket.close();

        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    }.start();
  }

}