/*
    * 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.commons.lang3;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.commons.lang3.arch.Processor;
  import org.apache.commons.lang3.stream.Streams;
  
  /**
   * Provides methods for identifying the architecture of the current JVM based on the {@code "os.arch"} system property.
   * <p>
   * Important: The {@code "os.arch"} system property returns the architecture used by the JVM not of the operating system.
   * </p>
   *
   * @since 3.6
   */
  public class ArchUtils {
  
      private static final Map<String, Processor> ARCH_TO_PROCESSOR;
  
      static {
          ARCH_TO_PROCESSOR = new HashMap<>();
          init();
      }
  
      /**
       * Adds the given {@link Processor} with the given key {@link String} to the map.
       *
       * @param key       The key as {@link String}.
       * @param processor The {@link Processor} to add.
       * @throws IllegalStateException If the key already exists.
       */
      private static void addProcessor(final String key, final Processor processor) {
          if (ARCH_TO_PROCESSOR.containsKey(key)) {
              throw new IllegalStateException("Key " + key + " already exists in processor map");
          }
          ARCH_TO_PROCESSOR.put(key, processor);
      }
  
      /**
       * Adds the given {@link Processor} with the given keys to the map.
       *
       * @param keys      The keys.
       * @param processor The {@link Processor} to add.
       * @throws IllegalStateException If the key already exists.
       */
      private static void addProcessors(final Processor processor, final String... keys) {
          Streams.of(keys).forEach(e -> addProcessor(e, processor));
      }
  
      /**
       * Gets a {@link Processor} object of the current JVM.
       *
       * <p>
       * Important: The {@code "os.arch"} system property returns the architecture used by the JVM not of the operating system.
       * </p>
       *
       * @return A {@link Processor} when supported, else {@code null}.
       */
      public static Processor getProcessor() {
          return getProcessor(SystemProperties.getOsArch());
      }
  
      /**
       * Gets a {@link Processor} object the given value {@link String}. The {@link String} must be like a value returned by the {@code "os.arch"} system
       * property.
       *
       * @param value A {@link String} like a value returned by the {@code os.arch} System Property.
       * @return A {@link Processor} when it exists, else {@code null}.
       */
      public static Processor getProcessor(final String value) {
          return ARCH_TO_PROCESSOR.get(value);
      }
  
      private static void init() {
          init_X86_32Bit();
          init_X86_64Bit();
          init_IA64_32Bit();
          init_IA64_64Bit();
          init_PPC_32Bit();
          init_PPC_64Bit();
          init_Aarch_64Bit();
          init_RISCV_32Bit();
         init_RISCV_64Bit();
     }
 
     private static void init_Aarch_64Bit() {
         addProcessors(new Processor(Processor.Arch.BIT_64, Processor.Type.AARCH_64), "aarch64");
     }
 
     private static void init_IA64_32Bit() {
         addProcessors(new Processor(Processor.Arch.BIT_32, Processor.Type.IA_64), "ia64_32", "ia64n");
     }
 
     private static void init_IA64_64Bit() {
         addProcessors(new Processor(Processor.Arch.BIT_64, Processor.Type.IA_64), "ia64", "ia64w");
     }
 
     private static void init_PPC_32Bit() {
         addProcessors(new Processor(Processor.Arch.BIT_32, Processor.Type.PPC), "ppc", "power", "powerpc", "power_pc", "power_rs");
     }
 
     private static void init_PPC_64Bit() {
         addProcessors(new Processor(Processor.Arch.BIT_64, Processor.Type.PPC), "ppc64", "power64", "powerpc64", "power_pc64", "power_rs64");
     }
 
     private static void init_RISCV_32Bit() {
         addProcessors(new Processor(Processor.Arch.BIT_32, Processor.Type.RISC_V), "riscv32");
     }
 
     private static void init_RISCV_64Bit() {
         addProcessors(new Processor(Processor.Arch.BIT_64, Processor.Type.RISC_V), "riscv64");
     }
 
     private static void init_X86_32Bit() {
         addProcessors(new Processor(Processor.Arch.BIT_32, Processor.Type.X86), "x86", "i386", "i486", "i586", "i686", "pentium");
     }
 
     private static void init_X86_64Bit() {
         addProcessors(new Processor(Processor.Arch.BIT_64, Processor.Type.X86), "x86_64", "amd64", "em64t", "universal");
     }
 
 }