kishida/MazeWeb.java

## MazeWeb.java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.nio.charset.Charset;

public class MazeWeb {
    public static void main(String[] args) throws IOException {

        record Position(int x, int y) {}
        final int[][] MAP = {
            {1, 1, 1, 1, 1, 1},
            {1, 0, 1, 0, 0, 1},
            {1, 0, 0, 0, 1, 1},
            {1, 0, 1, 0, 0, 1},
            {1, 1, 1, 1, 1, 1}
        };
        final Position GOAL = new Position(4, 3);
        Position current = new Position(1, 1);

        var server = new ServerSocket(80);
        for (;;) {
            var soc = server.accept();
            try(soc;
                var isr = new InputStreamReader(soc.getInputStream());
                var bur = new BufferedReader(isr);
                var w = new PrintWriter(soc.getOutputStream(), false,
                        Charset.forName("utf-8"))) {
               String req = bur.readLine();
               if (req == null) {
                   continue;
               }
               Position dir = switch(req.split(" ")[1]) {
                   case "/l" -> new Position(-1, 0);
                   case "/r" -> new Position( 1, 0);
                   case "/u" -> new Position( 0,-1);
                   case "/d" -> new Position( 0, 1);
                   default   -> new Position( 0, 0);
               };
               var next = new Position(current.x() + dir.x(), current.y() + dir.y());
               if (MAP[next.y()][next.x()] == 0) {
                   current = next;
               }
               while (!bur.readLine().isEmpty()) ;
               w.println("""
                         HTTP/1.1 200
                         content-type: text/html; charset=utf-8

                         <html><head><title>Hello</title>
                         </head>
                         <body><h1>Hello</h1>It works!<br>
                         <table>
                         """);
               for (int i = 0; i < MAP.length; ++i) {
                   w.println("<tr>");
                   for (int j = 0; j < MAP[0].length; ++j) {
                       w.print("<td>");
                       if (i == current.y() && j == current.x()) {
                           w.print("o");
                       } else if (MAP[i][j] == 1) {
                           w.print("*");
                       } else {
                           w.print(".");
                       }
                       w.print("</td>");
                   }
                   w.println("</tr>");
               }
               w.println("</table>");
               if (current.equals(GOAL)) {
                   w.println("<div>GOAL!!!</div>");
               }
               w.println("""
                         <a href="/l">←</a>
                         <a href="/r">→</a>
                         <a href="/u">↑</a>
                         <a href="/d">↓</a>
                         </body></html>
                         """);
           }
        }
    }

}
	import java.io.BufferedReader;
	import java.io.IOException;
	import java.io.InputStreamReader;
	import java.io.PrintWriter;
	import java.net.ServerSocket;
	import java.nio.charset.Charset;

	public class MazeWeb {
	public static void main(String[] args) throws IOException {

	record Position(int x, int y) {}
	final int[][] MAP = {
	{1, 1, 1, 1, 1, 1},
	{1, 0, 1, 0, 0, 1},
	{1, 0, 0, 0, 1, 1},
	{1, 0, 1, 0, 0, 1},
	{1, 1, 1, 1, 1, 1}
	};
	final Position GOAL = new Position(4, 3);
	Position current = new Position(1, 1);

	var server = new ServerSocket(80);
	for (;;) {
	var soc = server.accept();
	try(soc;
	var isr = new InputStreamReader(soc.getInputStream());
	var bur = new BufferedReader(isr);
	var w = new PrintWriter(soc.getOutputStream(), false,
	Charset.forName("utf-8"))) {
	String req = bur.readLine();
	if (req == null) {
	continue;
	}
	Position dir = switch(req.split(" ")[1]) {
	case "/l" -> new Position(-1, 0);
	case "/r" -> new Position( 1, 0);
	case "/u" -> new Position( 0,-1);
	case "/d" -> new Position( 0, 1);
	default -> new Position( 0, 0);
	};
	var next = new Position(current.x() + dir.x(), current.y() + dir.y());
	if (MAP[next.y()][next.x()] == 0) {
	current = next;
	}
	while (!bur.readLine().isEmpty()) ;
	w.println("""
	HTTP/1.1 200
	content-type: text/html; charset=utf-8

	<html><head><title>Hello</title>
	</head>
	<body><h1>Hello</h1>It works!<br>
	<table>
	""");
	for (int i = 0; i < MAP.length; ++i) {
	w.println("<tr>");
	for (int j = 0; j < MAP[0].length; ++j) {
	w.print("<td>");
	if (i == current.y() && j == current.x()) {
	w.print("o");
	} else if (MAP[i][j] == 1) {
	w.print("*");
	} else {
	w.print(".");
	}
	w.print("</td>");
	}
	w.println("</tr>");
	}
	w.println("</table>");
	if (current.equals(GOAL)) {
	w.println("<div>GOAL!!!</div>");
	}
	w.println("""
	<a href="/l">←</a>
	<a href="/r">→</a>
	<a href="/u">↑</a>
	<a href="/d">↓</a>
	</body></html>
	""");
	}
	}
	}

	}