content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   *
   *    http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.kafka.message;
  
  import java.io.BufferedWriter;
  import java.io.IOException;
  import java.util.Locale;
  import java.util.Map;
  import java.util.TreeMap;
  
  public final class MetadataRecordTypeGenerator implements TypeClassGenerator {
      private final HeaderGenerator headerGenerator;
      private final CodeBuffer buffer;
      private final TreeMap<Short, MessageSpec> apis;
  
      public MetadataRecordTypeGenerator(String packageName) {
          this.headerGenerator = new HeaderGenerator(packageName);
          this.apis = new TreeMap<>();
          this.buffer = new CodeBuffer();
      }
  
      @Override
      public String outputName() {
          return MessageGenerator.METADATA_RECORD_TYPE_JAVA;
      }
  
      @Override
      public void registerMessageType(MessageSpec spec) {
          if (spec.type() == MessageSpecType.METADATA) {
              short id = spec.apiKey().get();
              MessageSpec prevSpec = apis.put(id, spec);
              if (prevSpec != null) {
                  throw new RuntimeException("Duplicate metadata record entry for type " +
                      id + ". Original claimant: " + prevSpec.name() + ". New " +
                      "claimant: " + spec.name());
              }
          }
      }
  
      @Override
      public void generateAndWrite(BufferedWriter writer) throws IOException {
          generate();
          write(writer);
      }
  
      private void generate() {
          buffer.printf("public enum MetadataRecordType {%n");
          buffer.incrementIndent();
          generateEnumValues();
          buffer.printf("%n");
          generateInstanceVariables();
          buffer.printf("%n");
          generateEnumConstructor();
          buffer.printf("%n");
          generateFromApiKey();
          buffer.printf("%n");
          generateNewMetadataRecord();
          buffer.printf("%n");
          generateAccessor("id", "short");
          buffer.printf("%n");
          generateAccessor("lowestSupportedVersion", "short");
          buffer.printf("%n");
          generateAccessor("highestSupportedVersion", "short");
          buffer.printf("%n");
          generateToString();
          buffer.decrementIndent();
          buffer.printf("}%n");
          headerGenerator.generate();
      }
  
      private void generateEnumValues() {
          int numProcessed = 0;
          for (Map.Entry<Short, MessageSpec> entry : apis.entrySet()) {
              MessageSpec spec = entry.getValue();
              String name = spec.name();
              numProcessed++;
              buffer.printf("%s(\"%s\", (short) %d, (short) %d, (short) %d)%s%n",
                  MessageGenerator.toSnakeCase(name).toUpperCase(Locale.ROOT),
                  MessageGenerator.capitalizeFirst(name),
                  entry.getKey(),
                  entry.getValue().validVersions().lowest(),
                  entry.getValue().validVersions().highest(),
                  (numProcessed == apis.size()) ? ";" : ",");
          }
      }
  
      private void generateInstanceVariables() {
          buffer.printf("private final String name;%n");
          buffer.printf("private final short id;%n");
          buffer.printf("private final short lowestSupportedVersion;%n");
          buffer.printf("private final short highestSupportedVersion;%n");
      }
  
      private void generateEnumConstructor() {
          buffer.printf("MetadataRecordType(String name, short id, short lowestSupportedVersion, short highestSupportedVersion) {%n");
          buffer.incrementIndent();
          buffer.printf("this.name = name;%n");
          buffer.printf("this.id = id;%n");
          buffer.printf("this.lowestSupportedVersion = lowestSupportedVersion;%n");
          buffer.printf("this.highestSupportedVersion = highestSupportedVersion;%n");
          buffer.decrementIndent();
          buffer.printf("}%n");
      }
  
      private void generateFromApiKey() {
          buffer.printf("public static MetadataRecordType fromId(short id) {%n");
          buffer.incrementIndent();
          buffer.printf("switch (id) {%n");
          buffer.incrementIndent();
          for (Map.Entry<Short, MessageSpec> entry : apis.entrySet()) {
              buffer.printf("case %d:%n", entry.getKey());
              buffer.incrementIndent();
              buffer.printf("return %s;%n", MessageGenerator.
                  toSnakeCase(entry.getValue().name()).toUpperCase(Locale.ROOT));
              buffer.decrementIndent();
          }
          buffer.printf("default:%n");
          buffer.incrementIndent();
          headerGenerator.addImport(MessageGenerator.UNSUPPORTED_VERSION_EXCEPTION_CLASS);
          buffer.printf("throw new UnsupportedVersionException(\"Unknown metadata id \"" +
              " + id);%n");
          buffer.decrementIndent();
          buffer.decrementIndent();
          buffer.printf("}%n");
          buffer.decrementIndent();
          buffer.printf("}%n");
      }
  
      private void generateNewMetadataRecord() {
          headerGenerator.addImport(MessageGenerator.API_MESSAGE_CLASS);
          buffer.printf("public ApiMessage newMetadataRecord() {%n");
          buffer.incrementIndent();
          buffer.printf("switch (id) {%n");
          buffer.incrementIndent();
          for (Map.Entry<Short, MessageSpec> entry : apis.entrySet()) {
              buffer.printf("case %d:%n", entry.getKey());
              buffer.incrementIndent();
              buffer.printf("return new %s();%n",
                  MessageGenerator.capitalizeFirst(entry.getValue().name()));
              buffer.decrementIndent();
          }
          buffer.printf("default:%n");
          buffer.incrementIndent();
          headerGenerator.addImport(MessageGenerator.UNSUPPORTED_VERSION_EXCEPTION_CLASS);
          buffer.printf("throw new UnsupportedVersionException(\"Unknown metadata id \"" +
              " + id);%n");
          buffer.decrementIndent();
          buffer.decrementIndent();
          buffer.printf("}%n");
          buffer.decrementIndent();
          buffer.printf("}%n");
      }
  
      private void generateAccessor(String name, String type) {
          buffer.printf("public %s %s() {%n", type, name);
          buffer.incrementIndent();
          buffer.printf("return this.%s;%n", name);
          buffer.decrementIndent();
          buffer.printf("}%n");
      }
  
      private void generateToString() {
          buffer.printf("@Override%n");
          buffer.printf("public String toString() {%n");
          buffer.incrementIndent();
          buffer.printf("return this.name();%n");
          buffer.decrementIndent();
          buffer.printf("}%n");
      }
  
      private void write(BufferedWriter writer) throws IOException {
          headerGenerator.buffer().write(writer);
          buffer.write(writer);
      }
  }
  