/**
    * Copyright (C) 2014-2016 Philip Helger (www.helger.com)
    * philip[at]helger[dot]com
    *
    * Licensed 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 com.helger.schematron.pure.binding.xpath;
  
  import java.util.Map;
  
  import javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  import javax.annotation.concurrent.NotThreadSafe;
  
  import com.helger.commons.ValueEnforcer;
  import com.helger.commons.annotation.Nonempty;
  import com.helger.commons.annotation.ReturnsMutableCopy;
  import com.helger.commons.collection.ext.CommonsTreeMap;
  import com.helger.commons.collection.ext.ICommonsNavigableMap;
  import com.helger.commons.compare.IComparator;
  import com.helger.commons.state.EChange;
  import com.helger.commons.string.StringHelper;
  import com.helger.commons.string.ToStringGenerator;
  
  /**
   * This class manages all variables present in Schematron <let> elements.
   *
   * @author Philip Helger
   */
  @NotThreadSafe
  public class PSXPathVariables implements IPSXPathVariables
  {
    @Nonnull
    @ReturnsMutableCopy
    private static ICommonsNavigableMap <String, String> _createMap ()
    {
      return new CommonsTreeMap <> (IComparator.getComparatorStringLongestFirst ());
    }
  
    private final ICommonsNavigableMap <String, String> m_aMap;
  
    public PSXPathVariables ()
    {
      m_aMap = _createMap ();
    }
  
    public PSXPathVariables (@Nonnull final IPSXPathVariables aOther)
    {
      m_aMap = aOther.getAll ();
    }
  
    /**
     * Add a new variable.
     *
     * @param aEntry
     *        The entry to be added - key is the variable name and value is the
     *        variable value. May not be <code>null</code>.
     * @return {@link EChange#UNCHANGED} if a variable with the same name is
     *         already present. Never <code>null</code>.
     */
    @Nonnull
    public EChange add (@Nonnull final Map.Entry <String, String> aEntry)
    {
      return add (aEntry.getKey (), aEntry.getValue ());
    }
  
    /**
     * Add a new variable.
     *
     * @param sName
     *        The name of the variable. May neither be <code>null</code> nor
     *        empty.
     * @param sValue
     *        The value of the variable. May neither be <code>null</code> nor
     *        empty.
     * @return {@link EChange#UNCHANGED} if a variable with the same name is
     *         already present. Never <code>null</code>.
     */
    @Nonnull
    public EChange add (@Nonnull @Nonempty final String sName, @Nonnull @Nonempty final String sValue)
    {
      ValueEnforcer.notEmpty (sName, "Name");
      ValueEnforcer.notEmpty (sValue, "Value");
  
      // Prepend the "$" prefix to the variable name
      final String sRealName = PSXPathQueryBinding.PARAM_VARIABLE_PREFIX + sName;
      if (m_aMap.containsKey (sRealName))
        return EChange.UNCHANGED;
  
     // Apply all existing variables to this variable value!
     // This ensures that all variables used in variables are resolved correctly
     // as long as the order of declaration is correct.
     // Additionally this means that the order of the variables in this class is
     // irrelevant
     final String sRealValue = getAppliedReplacement (sValue);
     m_aMap.put (sRealName, sRealValue);
     return EChange.CHANGED;
   }
 
   @Nullable
   public String getAppliedReplacement (@Nullable final String sText)
   {
     return PSXPathQueryBinding.getWithParamTextsReplacedStatic (sText, m_aMap);
   }
 
   /**
    * Remove the variable with the specified name
    *
    * @param sVarName
    *        The name of the variable to be removed. May be <code>null</code>.
    * @return {@link EChange#CHANGED} if the variable was removed successfully.
    *         Never <code>null</code>.
    */
   @Nonnull
   public EChange remove (@Nullable final String sVarName)
   {
     if (StringHelper.hasText (sVarName))
       if (m_aMap.remove (PSXPathQueryBinding.PARAM_VARIABLE_PREFIX + sVarName) == null)
         return EChange.CHANGED;
     return EChange.UNCHANGED;
   }
 
   /**
    * Remove all variables with the specified names
    *
    * @param aVars
    *        A list of variable names to be removed. May be <code>null</code>.
    * @return {@link EChange#CHANGED} if at least one variable was removed
    *         successfully. Never <code>null</code>.
    */
   @Nonnull
   public EChange removeAll (@Nullable final Iterable <String> aVars)
   {
     EChange eChange = EChange.UNCHANGED;
     if (aVars != null)
       for (final String sName : aVars)
         eChange = eChange.or (remove (sName));
     return eChange;
   }
 
   @Nonnull
   @ReturnsMutableCopy
   public ICommonsNavigableMap <String, String> getAll ()
   {
     return m_aMap.getClone ();
   }
 
   public boolean contains (@Nullable final String sName)
   {
     if (StringHelper.hasNoText (sName))
       return false;
     return m_aMap.containsKey (sName);
   }
 
   @Nullable
   public String get (@Nullable final String sName)
   {
     if (StringHelper.hasNoText (sName))
       return null;
     return m_aMap.get (sName);
   }
 
   @Nonnull
   @ReturnsMutableCopy
   public PSXPathVariables getClone ()
   {
     return new PSXPathVariables (this);
   }
 
   @Override
   public String toString ()
   {
     return new ToStringGenerator (this).append ("map", m_aMap).toString ();
   }
 }