package com.grady.diytomcat;

import com.grady.diytomcat.handler.DiyNettyTomcatHandler;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpRequestDecoder;
import io.netty.handler.codec.http.HttpResponseEncoder;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.util.HashMap;
import java.util.List;

public class DiyTomcat {

    private int port = 8080;

    public static final HashMap<String, DiyNettyServlet> SERVLET_MAPPING = new HashMap<>();

    public static final HashMap<String,String> URL_MAPPING = new HashMap<>();


    static {
        loadServlet();
    }

    private static void loadServlet() {
        try {
            //獲取web.xml目錄地址
            String path = DiyTomcat.class.getResource("/").getPath();
            SAXReader reader = new SAXReader();
            //讀取web.xml檔案
            Document document = reader.read(new File(path + "web.xml"));
            //獲取根標籤（servlet和servlet-mapping），放在一個List中
            Element rootElement = document.getRootElement();
            List<Element> elements = rootElement.elements();
            //迴圈將對映寫進map對映裡
            for(Element element : elements){
                if ("servlet".equalsIgnoreCase(element.getName())){
                    Element servletName = element.element("servlet-name");
                    Element servletClass = element.element("servlet-class");
                    //需要注意的是servletMapping對映的第二個引數，要通過反射的方式進行例項化
                    SERVLET_MAPPING.put(servletName.getText(),
                            (DiyNettyServlet) Class.forName(servletClass.getText().trim()).newInstance());
                }else if ("servlet-mapping".equalsIgnoreCase(element.getName())){
                    Element servletName = element.element("servlet-name");
                    Element urlPattern = element.element("url-pattern");
                    URL_MAPPING.put(urlPattern.getText(), servletName.getText());
                }
            }
        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        }
    }

    public void start() throws IOException {
        // Boss執行緒
        NioEventLoopGroup bossGroup = new NioEventLoopGroup();
        // worker執行緒
        NioEventLoopGroup workerGroup = new NioEventLoopGroup();

        // 1.建立物件
        ServerBootstrap server = new ServerBootstrap();
        //2. 配置引數
        server.group(bossGroup,workerGroup)
                // 主執行緒處理類
                .channel(NioServerSocketChannel.class)
                // 子執行緒處理類 Handler
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    protected void initChannel(SocketChannel socketChannel) throws Exception {
                        socketChannel.pipeline().addLast(new HttpResponseEncoder());
                        socketChannel.pipeline().addLast(new HttpRequestDecoder());
                        socketChannel.pipeline().addLast(new DiyNettyTomcatHandler());
                    }
                })
                //針對主執行緒的配置，最大執行緒數128
                .option(ChannelOption.SO_BACKLOG,128)
                // 針對子執行緒的配置，保持長連線
                .childOption(ChannelOption.SO_KEEPALIVE,true);

        try {
            // 3 啟動伺服器
            ChannelFuture f = server.bind(port).sync();
            System.out.println("DiyTomcat啟動成功，監聽的埠是：" + port);
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}