feature(statement preview): add preview for statement

just like the stub

Author: Jay Ng

runner/src/main/java/com/codingame/gameengine/runner/Renderer.java

@@ -682,8 +682,7 @@ public void handleRequest(HttpServerExchange exchange) throws Exception {
                                             }
 
                                             exchange.setStatusCode(StatusCodes.OK);
-                                        }
-                                        if (exchange.getRelativePath().equals("/stub")) {
+                                        } else if (exchange.getRelativePath().equals("/stub")) {
                                             File stubFile = sourceFolderPath.resolve("config/stub.txt").toFile();
                                             if (exchange.getRequestMethod().equalToString("GET")) {
                                                 String stub = FileUtils.readFileToString(stubFile, StandardCharsets.UTF_8);
@@ -700,6 +699,23 @@ public void handleRequest(HttpServerExchange exchange) throws Exception {
                                             } else {
                                                 exchange.setStatusCode(StatusCodes.NOT_FOUND);
                                             }
+                                        } else if (exchange.getRelativePath().equals("/statement")) {
+                                          File statementFile = sourceFolderPath.resolve("config/statement_en.html").toFile();
+                                          if (exchange.getRequestMethod().equalToString("GET")) {
+                                              String statement = FileUtils.readFileToString(statementFile, StandardCharsets.UTF_8);
+                                              exchange.getResponseSender().send(statement);
+                                          } else if (exchange.getRequestMethod().equalToString("PUT")) {
+                                              exchange.getRequestReceiver().receiveFullString((e, data) -> {
+                                                  try {
+                                                      FileUtils.write(statementFile, data, StandardCharsets.UTF_8);
+                                                      exchange.setStatusCode(StatusCodes.CREATED);
+                                                  } catch (IOException ex) {
+                                                      sendException(e, ex, StatusCodes.BAD_REQUEST);
+                                                  }
+                                              });
+                                          } else {
+                                              exchange.setStatusCode(StatusCodes.NOT_FOUND);
+                                          }
                                         }
                                     } catch (MissingConfigException e) {
                                         sendException(exchange, e, StatusCodes.UNPROCESSABLE_ENTITY);