/*
 * 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.config.internal;

import static org.apache.juneau.common.utils.Utils.*;
import static org.apache.juneau.internal.CollectionUtils.*;

import java.io.*;
import java.util.*;

import org.apache.juneau.common.utils.*;

/**
 * Represents a single entry in a configuration.
 *
 * This is a read-only object.
 */
public class ConfigMapEntry {
   final String rawLine;
   final String key, value, comment;
   final String modifiers;
   final List<String> preLines;

   static final ConfigMapEntry NULL = new ConfigMapEntry(null, null, null, null, null);

   ConfigMapEntry(String line, List<String> preLines) {
      this.rawLine = line;
      var i = line.indexOf('=');
      var key2 = line.substring(0, i).trim();

      var m1 = key2.indexOf('<');
      var m2 = key2.indexOf('>');

      modifiers = nullIfEmpty((m1 > -1 && m2 > m1) ? key2.substring(m1+1, m2) : null);

      this.key = m1 == -1 ? key2 : key2.substring(0, m1);

      line = line.substring(i+1);

      i = line.indexOf('#');
      if (i != -1) {
         var l2 = Utils.splita(line, '#', 2);
         line = l2[0];
         if (l2.length == 2)
            this.comment = l2[1].trim();
         else
            this.comment = null;
      } else {
         this.comment = null;
      }

      this.value = StringUtils.replaceUnicodeSequences(line.trim());

      this.preLines = preLines == null ? Collections.emptyList() : u(copyOf(preLines));
   }

   ConfigMapEntry(String key, String value, String modifiers, String comment, List<String> preLines) {
      this.rawLine = null;
      this.key = key;
      this.value = value;
      this.comment = comment;
      this.modifiers = modifiers;
      this.preLines = preLines == null ? Collections.emptyList() : u(copyOf(preLines));
   }

   /**
    * Returns the name of this entry.
    *
    * @return The name of this entry.
    */
   public String getKey() {
      return key;
   }

   /**
    * Returns the raw value of this entry.
    *
    * @return The raw value of this entry.
    */
   public String getValue() {
      return value;
   }

   /**
    * Returns the same-line comment of this entry.
    *
    * @return The same-line comment of this entry.
    */
   public String getComment() {
      return comment;
   }

   /**
    * Returns the pre-lines of this entry.
    *
    * @return The pre-lines of this entry as an unmodifiable list.
    */
   public List<String> getPreLines() {
      return preLines;
   }

   /**
    * Returns the modifiers for this entry.
    *
    * @return The modifiers for this entry, or <jk>null</jk> if it has no modifiers.
    */
   public String getModifiers() {
      return modifiers;
   }

   Writer writeTo(Writer w) throws IOException {
      if (value == null)
         return w;
      for (var pl : preLines)
         w.append(pl).append('\n');
      if (rawLine != null) {
         for (var i = 0; i < rawLine.length(); i++) {
            var c = rawLine.charAt(i);
            if (c == '\n')
               w.append('\n').append('\t');
            else if (c != '\r')
               w.append(c);
         }
         w.append('\n');
      } else {
         w.append(key);
         if (modifiers != null)
            w.append('<').append(modifiers).append('>');
         w.append(" = ");

         var val = value;
         for (var i = 0; i < val.length(); i++) {
            var c = val.charAt(i);
            if (c == '\n')
               w.append('\n').append('\t');
            else if (c != '\r') {
               if (REPLACE_CHARS.contains(c) || (Character.isISOControl(c) && ! (c == '\n' || c == '\r' || c == '\t'))) {
                  w.append(StringUtils.unicodeSequence(c));
               } else {
                  w.append(c);
               }
            }
         }

         if (isNotEmpty(comment))
            w.append(" # ").append(comment);

         w.append('\n');
      }
      return w;
   }

   private static final AsciiSet REPLACE_CHARS = AsciiSet.of("\\#");
}