/*
    * 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
    *
    *      https://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.io;
  
  import java.io.File;
  import java.util.Objects;
  import java.util.stream.Stream;
  
  /**
   * Enumeration of IO case sensitivity.
   * <p>
   * Different filing systems have different rules for case-sensitivity.
   * Windows is case-insensitive, Unix is case-sensitive.
   * </p>
   * <p>
   * This class captures that difference, providing an enumeration to
   * control how file name comparisons should be performed. It also provides
   * methods that use the enumeration to perform comparisons.
   * </p>
   * <p>
   * Wherever possible, you should use the {@code check} methods in this
   * class to compare file names.
   * </p>
   *
   * @since 1.3
   */
  public enum IOCase {
  
      /**
       * The constant for case-sensitive regardless of operating system.
       */
      SENSITIVE("Sensitive", true),
  
      /**
       * The constant for case-insensitive regardless of operating system.
       */
      INSENSITIVE("Insensitive", false),
  
      /**
       * The constant for case sensitivity determined by the current operating system.
       * Windows is case-insensitive when comparing file names, Unix is case-sensitive.
       * <p>
       * <strong>Note:</strong> This only caters for Windows and Unix. Other operating
       * systems (e.g. OSX and OpenVMS) are treated as case-sensitive if they use the
       * Unix file separator and case-insensitive if they use the Windows file separator
       * (see {@link File#separatorChar}).
       * </p>
       * <p>
       * If you serialize this constant on Windows, and deserialize on Unix, or vice
       * versa, then the value of the case-sensitivity flag will change.
       * </p>
       */
      SYSTEM("System", FileSystem.getCurrent().isCaseSensitive());
  
      /** Serialization version. */
      private static final long serialVersionUID = -6343169151696340687L;
  
      /**
       * Looks up an IOCase by name.
       *
       * @param name  the name to find
       * @return the IOCase object
       * @throws IllegalArgumentException if the name is invalid
       */
      public static IOCase forName(final String name) {
          return Stream.of(values()).filter(ioCase -> ioCase.getName().equals(name)).findFirst()
                  .orElseThrow(() -> new IllegalArgumentException("Illegal IOCase name: " + name));
      }
  
      /**
       * Tests for cases sensitivity in a null-safe manner.
       *
       * @param ioCase an IOCase.
       * @return true if the input is non-null and {@link #isCaseSensitive()}.
       * @since 2.10.0
       */
      public static boolean isCaseSensitive(final IOCase ioCase) {
          return ioCase != null && ioCase.isCaseSensitive();
      }
  
      /**
       * Returns the given value if not-null, the defaultValue if null.
       *
       * @param value the value to test.
       * @param defaultValue the default value.
      * @return the given value if not-null, the defaultValue if null.
      * @since 2.12.0
      */
     public static IOCase value(final IOCase value, final IOCase defaultValue) {
         return value != null ? value : defaultValue;
     }
 
     /** The enumeration name. */
     private final String name;
 
     /** The sensitivity flag. */
     private final transient boolean sensitive;
 
     /**
      * Constructs a new instance.
      *
      * @param name  the name.
      * @param sensitive  the sensitivity.
      */
     IOCase(final String name, final boolean sensitive) {
         this.name = name;
         this.sensitive = sensitive;
     }
 
     /**
      * Compares two strings using the case-sensitivity rule.
      * <p>
      * This method mimics {@link String#compareTo} but takes case-sensitivity
      * into account.
      * </p>
      *
      * @param str1  the first string to compare, not null.
      * @param str2  the second string to compare, not null.
      * @return true if equal using the case rules.
      * @throws NullPointerException if either string is null.
      */
     public int checkCompareTo(final String str1, final String str2) {
         Objects.requireNonNull(str1, "str1");
         Objects.requireNonNull(str2, "str2");
         return sensitive ? str1.compareTo(str2) : str1.compareToIgnoreCase(str2);
     }
 
     /**
      * Checks if one string ends with another using the case-sensitivity rule.
      * <p>
      * This method mimics {@link String#endsWith} but takes case-sensitivity
      * into account.
      * </p>
      *
      * @param str  the string to check.
      * @param end  the end to compare against.
      * @return true if equal using the case rules, false if either input is null.
      */
     public boolean checkEndsWith(final String str, final String end) {
         if (str == null || end == null) {
             return false;
         }
         final int endLen = end.length();
         return str.regionMatches(!sensitive, str.length() - endLen, end, 0, endLen);
     }
 
     /**
      * Compares two strings using the case-sensitivity rule.
      * <p>
      * This method mimics {@link String#equals} but takes case-sensitivity
      * into account.
      * </p>
      *
      * @param str1  the first string to compare.
      * @param str2  the second string to compare.
      * @return true if equal using the case rules.
      */
     public boolean checkEquals(final String str1, final String str2) {
         return str1 == str2 || str1 != null && (sensitive ? str1.equals(str2) : str1.equalsIgnoreCase(str2));
     }
 
     /**
      * Checks if one string contains another starting at a specific index using the
      * case-sensitivity rule.
      * <p>
      * This method mimics parts of {@link String#indexOf(String, int)}
      * but takes case-sensitivity into account.
      * </p>
      *
      * @param str  the string to check.
      * @param strStartIndex  the index to start at in str.
      * @param search  the start to search for.
      * @return the first index of the search String,
      *  -1 if no match or {@code null} string input.
      * @since 2.0
      */
     public int checkIndexOf(final String str, final int strStartIndex, final String search) {
         if (str != null && search != null) {
             final int endIndex = str.length() - search.length();
             if (endIndex >= strStartIndex) {
                 for (int i = strStartIndex; i <= endIndex; i++) {
                     if (checkRegionMatches(str, i, search)) {
                         return i;
                     }
                 }
             }
         }
         return -1;
     }
 
     /**
      * Checks if one string contains another at a specific index using the case-sensitivity rule.
      * <p>
      * This method mimics parts of {@link String#regionMatches(boolean, int, String, int, int)}
      * but takes case-sensitivity into account.
      * </p>
      *
      * @param str  the string to check.
      * @param strStartIndex  the index to start at in str.
      * @param search  the start to search for,.
      * @return true if equal using the case rules.
      */
     public boolean checkRegionMatches(final String str, final int strStartIndex, final String search) {
         return str != null && search != null && str.regionMatches(!sensitive, strStartIndex, search, 0, search.length());
     }
 
     /**
      * Checks if one string starts with another using the case-sensitivity rule.
      * <p>
      * This method mimics {@link String#startsWith(String)} but takes case-sensitivity
      * into account.
      * </p>
      *
      * @param str  the string to check.
      * @param start  the start to compare against.
      * @return true if equal using the case rules, false if either input is null.
      */
     public boolean checkStartsWith(final String str, final String start) {
         return str != null && start != null && str.regionMatches(!sensitive, 0, start, 0, start.length());
     }
 
     /**
      * Gets the name of the constant.
      *
      * @return the name of the constant
      */
     public String getName() {
         return name;
     }
 
     /**
      * Does the object represent case-sensitive comparison.
      *
      * @return true if case-sensitive.
      */
     public boolean isCaseSensitive() {
         return sensitive;
     }
 
     /**
      * Replaces the enumeration from the stream with a real one.
      * This ensures that the correct flag is set for SYSTEM.
      *
      * @return the resolved object.
      */
     private Object readResolve() {
         return forName(name);
     }
 
     /**
      * Gets a string describing the sensitivity.
      *
      * @return a string describing the sensitivity.
      */
     @Override
     public String toString() {
         return name;
     }
 
 }