/*
 * 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.juneau.common.utils;

import java.util.*;

/**
 * Stores a set of ASCII characters for quick lookup.
 */
public class AsciiSet {

   //-----------------------------------------------------------------------------------------------------------------
   // Static
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Creates an ASCII set with the specified characters.
    *
    * @param chars The characters to keep in this store.
    * @return A new object.
    */
   public static AsciiSet of(String chars) {
      return new Builder().chars(chars).build();
   }

   /**
    * Creates a builder for an ASCII set.
    *
    * @return A new builder.
    */
   public static AsciiSet.Builder create() {
      return new Builder();
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Builder
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Builder class.
    */
   public static class Builder {
      final boolean[] store = new boolean[128];

      /**
       * Adds a range of characters to this set.
       *
       * @param start The start character.
       * @param end The end character.
       * @return This object.
       */
      public AsciiSet.Builder range(char start, char end) {
         for (var c = start; c <= end; c++)
            if (c < 128)
               store[c] = true;
         return this;
      }

      /**
       * Shortcut for calling multiple ranges.
       *
       * @param s Strings of the form "A-Z" where A and Z represent the first and last characters in the range.
       * @return This object.
       */
      public AsciiSet.Builder ranges(String...s) {
         for (var ss : s) {
            if (ss.length() != 3 || ss.charAt(1) != '-')
               throw new IllegalArgumentException("Value passed to ranges() must be 3 characters");
            range(ss.charAt(0), ss.charAt(2));
         }
         return this;
      }

      /**
       * Adds a set of characters to this set.
       *
       * @param chars The characters to keep in this store.
       * @return This object.
       */
      public AsciiSet.Builder chars(String chars) {
         for (var i = 0; i < chars.length(); i++) {
            var c = chars.charAt(i);
            if (c < 128)
               store[c] = true;
         }
         return this;
      }

      /**
       * Adds a set of characters to this set.
       *
       * @param chars The characters to keep in this store.
       * @return This object.
       */
      public Builder chars(char...chars) {
         for (var i = 0; i < chars.length; i++)
            if (chars[i] < 128)
               store[chars[i]] = true;
         return this;
      }

      /**
       * Create a new {@link AsciiSet} object with the contents of this builder.
       *
       * @return A new {link AsciiSet} object.
       */
      public AsciiSet build() {
         return new AsciiSet(store);
      }
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Instance
   //-----------------------------------------------------------------------------------------------------------------

   private final boolean[] store;

   AsciiSet(boolean[] store) {
      this.store = Arrays.copyOf(store, store.length);
   }

   /**
    * Copies an existing {@link AsciiSet} so that you can augment it with additional values.
    *
    * @return A builder initialized to the same characters in the copied set.
    */
   public AsciiSet.Builder copy() {
      var b = new Builder();
      System.arraycopy(store, 0, b.store, 0, 128);
      return b;
   }


   /**
    * Returns <jk>true</jk> if the specified character is in this store.
    *
    * @param c The character to check.
    * @return <jk>true</jk> if the specified character is in this store.
    */
   public boolean contains(char c) {
      if (c > 127)
         return false;
      return store[c];
   }

   /**
    * Returns <jk>true</jk> if the specified character is in this store.
    *
    * @param c The character to check.
    * @return <jk>true</jk> if the specified character is in this store.
    */
   public boolean contains(int c) {
      if (c < 0 || c > 127)
         return false;
      return store[c];
   }

   /**
    * Returns <jk>true</jk> if the specified string contains at least one character in this set.
    *
    * @param s The string to test.
    * @return <jk>true</jk> if the string is not null and contains at least one character in this set.
    */
   public boolean contains(CharSequence s) {
      if (s == null)
         return false;
      for (var i = 0; i < s.length(); i++)
         if (contains(s.charAt(i)))
            return true;
      return false;
   }

   /**
    * Returns <jk>true</jk> if the specified string contains only characters in this set.
    *
    * @param s The string to test.
    * @return
    *    <jk>true</jk> if the string contains only characters in this set.
    *    <br>Nulls always return <jk>false</jk>.
    *    <br>Blanks always return <jk>true</jk>.
    */
   public boolean containsOnly(String s) {
      if (s == null)
         return false;
      for (var i = 0; i < s.length(); i++)
         if (! contains(s.charAt(i)))
            return false;
      return true;
   }
}