/*
    * ModeShape (http://www.modeshape.org)
    * See the COPYRIGHT.txt file distributed with this work for information
    * regarding copyright ownership.  Some portions may be licensed
    * to Red Hat, Inc. under one or more contributor license agreements.
    * See the AUTHORS.txt file in the distribution for a full listing of 
    * individual contributors.
    *
    * ModeShape is free software. Unless otherwise indicated, all code in ModeShape
   * is licensed to you under the terms of the GNU Lesser General Public License as
   * published by the Free Software Foundation; either version 2.1 of
   * the License, or (at your option) any later version.
   * 
   * ModeShape is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this software; if not, write to the Free
   * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
   */
  package org.modeshape.graph.query.process;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.NoSuchElementException;
  import java.util.Set;
  import java.util.concurrent.atomic.AtomicBoolean;
  import net.jcip.annotations.Immutable;
  import org.modeshape.common.util.CheckArg;
  import org.modeshape.graph.GraphI18n;
  import org.modeshape.graph.Location;
  import org.modeshape.graph.query.QueryResults.Columns;
  import org.modeshape.graph.query.model.Column;
  import org.modeshape.graph.query.model.Constraint;
  import org.modeshape.graph.query.model.FullTextSearch;
  import org.modeshape.graph.query.model.Visitors;
  
  /**
   * Defines the columns associated with the results of a query. This definition allows the values to be accessed
   */
  @Immutable
  public class QueryResultColumns implements Columns {
      private static final long serialVersionUID = 1L;
  
      protected static final List<Column> NO_COLUMNS = Collections.<Column>emptyList();
      protected static final QueryResultColumns EMPTY = new QueryResultColumns(false, null);
  
      protected static final String DEFAULT_SELECTOR_NAME = "Results";
  
      /**
       * Get an empty results column definition.
       * 
       * @return the empty columns definition; never null
       */
      public static QueryResultColumns empty() {
          return EMPTY;
      }
  
      private final int tupleSize;
      private final List<Column> columns;
      private final List<String> columnNames;
      private final List<String> selectorNames;
      private List<String> tupleValueNames;
      private final Map<String, Column> columnsByName;
      private final Map<String, Integer> columnIndexByColumnName;
      private final Map<String, Integer> locationIndexBySelectorName;
      private final Map<String, Integer> locationIndexByColumnName;
      private final Map<Integer, Integer> locationIndexByColumnIndex;
      private final Map<String, Map<String, Integer>> columnIndexByPropertyNameBySelectorName;
      private final Map<String, Integer> fullTextSearchScoreIndexBySelectorName;
  
      /**
       * Create a new definition for the query results given the supplied columns.
       * 
       * @param columns the columns that define the results; should never be modified directly
       * @param includeFullTextSearchScores true if room should be made in the tuples for the full-text search scores for each
       *        {@link Location}, or false otherwise
       */
      public QueryResultColumns( List<Column> columns,
                                 boolean includeFullTextSearchScores ) {
          this(includeFullTextSearchScores, columns);
          CheckArg.isNotEmpty(columns, "columns");
      }
  
      /**
       * Create a new definition for the query results given the supplied columns.
       * 
       * @param includeFullTextSearchScores true if room should be made in the tuples for the full-text search scores for each
       *        {@link Location}, or false otherwise
       * @param columns the columns that define the results; should never be modified directly
      */
     protected QueryResultColumns( boolean includeFullTextSearchScores,
                                   List<Column> columns ) {
         this.columns = columns != null ? Collections.<Column>unmodifiableList(columns) : NO_COLUMNS;
         this.columnsByName = new HashMap<String, Column>();
         this.columnIndexByColumnName = new HashMap<String, Integer>();
         Set<String> selectors = new HashSet<String>();
         final int columnCount = this.columns.size();
         Integer selectorIndex = new Integer(columnCount - 1);
         this.locationIndexBySelectorName = new HashMap<String, Integer>();
         this.locationIndexByColumnIndex = new HashMap<Integer, Integer>();
         this.locationIndexByColumnName = new HashMap<String, Integer>();
         this.columnIndexByPropertyNameBySelectorName = new HashMap<String, Map<String, Integer>>();
         List<String> selectorNames = new ArrayList<String>(columnCount);
         List<String> names = new ArrayList<String>(columnCount);
         for (int i = 0, max = this.columns.size(); i != max; ++i) {
             Column column = this.columns.get(i);
             assert column != null;
             String columnName = column.getColumnName();
             assert columnName != null;
             if (columnsByName.put(columnName, column) != null) {
                 assert false : "Column names must be unique";
             }
             names.add(columnName);
             columnIndexByColumnName.put(columnName, new Integer(i));
             String selectorName = column.getSelectorName().getName();
             if (selectors.add(selectorName)) {
                 selectorNames.add(selectorName);
                 selectorIndex = new Integer(selectorIndex.intValue() + 1);
                 locationIndexBySelectorName.put(selectorName, selectorIndex);
             }
             locationIndexByColumnIndex.put(new Integer(i), selectorIndex);
             locationIndexByColumnName.put(columnName, selectorIndex);
             // Insert the entry by selector name and property name ...
             Map<String, Integer> byPropertyName = columnIndexByPropertyNameBySelectorName.get(selectorName);
             if (byPropertyName == null) {
                 byPropertyName = new HashMap<String, Integer>();
                 columnIndexByPropertyNameBySelectorName.put(selectorName, byPropertyName);
             }
             byPropertyName.put(column.getPropertyName(), new Integer(i));
         }
         if (columns != null && selectorNames.isEmpty()) {
             String selectorName = DEFAULT_SELECTOR_NAME;
             selectorNames.add(selectorName);
             locationIndexBySelectorName.put(selectorName, 0);
         }
         this.selectorNames = Collections.unmodifiableList(selectorNames);
         this.columnNames = Collections.unmodifiableList(names);
         if (includeFullTextSearchScores) {
             this.fullTextSearchScoreIndexBySelectorName = new HashMap<String, Integer>();
             int index = columnNames.size() + selectorNames.size();
             for (String selectorName : selectorNames) {
                 fullTextSearchScoreIndexBySelectorName.put(selectorName, new Integer(index++));
             }
             this.tupleSize = columnNames.size() + selectorNames.size() + selectorNames.size();
         } else {
             this.fullTextSearchScoreIndexBySelectorName = null;
             this.tupleSize = columnNames.size() + selectorNames.size();
         }
     }
 
     public static boolean includeFullTextScores( Iterable<Constraint> constraints ) {
         for (Constraint constraint : constraints) {
             if (includeFullTextScores(constraint)) return true;
         }
         return false;
     }
 
     public static boolean includeFullTextScores( Constraint constraint ) {
         final AtomicBoolean includeFullTextScores = new AtomicBoolean(false);
         if (constraint != null) {
             Visitors.visitAll(constraint, new Visitors.AbstractVisitor() {
                 @Override
                 public void visit( FullTextSearch obj ) {
                     includeFullTextScores.set(true);
                 }
             });
         }
         return includeFullTextScores.get();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#subSelect(java.util.List)
      */
     public Columns subSelect( List<Column> columns ) {
         return new QueryResultColumns(columns, this);
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#subSelect(org.modeshape.graph.query.model.Column[])
      */
     public Columns subSelect( Column... columns ) {
         return new QueryResultColumns(Arrays.asList(columns), this);
     }
 
     private QueryResultColumns( List<Column> columns,
                                 QueryResultColumns wrappedAround ) {
         assert columns != null;
         this.columns = Collections.unmodifiableList(columns);
         this.columnsByName = new HashMap<String, Column>();
         this.columnIndexByColumnName = new HashMap<String, Integer>();
         this.locationIndexBySelectorName = new HashMap<String, Integer>();
         this.locationIndexByColumnIndex = new HashMap<Integer, Integer>();
         this.locationIndexByColumnName = new HashMap<String, Integer>();
         this.columnIndexByPropertyNameBySelectorName = new HashMap<String, Map<String, Integer>>();
         this.selectorNames = new ArrayList<String>(columns.size());
         List<String> names = new ArrayList<String>(columns.size());
         for (int i = 0, max = this.columns.size(); i != max; ++i) {
             Column column = this.columns.get(i);
             assert column != null;
             String columnName = column.getColumnName();
             assert columnName != null;
             if (columnsByName.put(columnName, column) != null) {
                 assert false : "Column names must be unique";
             }
             names.add(columnName);
             Integer columnIndex = new Integer(wrappedAround.getColumnIndexForName(columnName));
             columnIndexByColumnName.put(columnName, columnIndex);
             String selectorName = column.getSelectorName().getName();
             if (!selectorNames.contains(selectorName)) selectorNames.add(selectorName);
             Integer selectorIndex = new Integer(wrappedAround.getLocationIndex(selectorName));
             locationIndexBySelectorName.put(selectorName, selectorIndex);
             locationIndexByColumnIndex.put(new Integer(0), selectorIndex);
             locationIndexByColumnName.put(columnName, selectorIndex);
             // Insert the entry by selector name and property name ...
             Map<String, Integer> byPropertyName = columnIndexByPropertyNameBySelectorName.get(selectorName);
             if (byPropertyName == null) {
                 byPropertyName = new HashMap<String, Integer>();
                 columnIndexByPropertyNameBySelectorName.put(selectorName, byPropertyName);
             }
             byPropertyName.put(column.getPropertyName(), columnIndex);
         }
         if (selectorNames.isEmpty()) {
             String selectorName = DEFAULT_SELECTOR_NAME;
             selectorNames.add(selectorName);
             locationIndexBySelectorName.put(selectorName, 0);
         }
         this.columnNames = Collections.unmodifiableList(names);
         if (wrappedAround.fullTextSearchScoreIndexBySelectorName != null) {
             this.fullTextSearchScoreIndexBySelectorName = new HashMap<String, Integer>();
             int index = columnNames.size() + selectorNames.size();
             for (String selectorName : selectorNames) {
                 fullTextSearchScoreIndexBySelectorName.put(selectorName, new Integer(index++));
             }
             this.tupleSize = columnNames.size() + selectorNames.size() + selectorNames.size();
         } else {
             this.fullTextSearchScoreIndexBySelectorName = null;
             this.tupleSize = columnNames.size() + selectorNames.size();
         }
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getColumns()
      */
     public List<Column> getColumns() {
         return columns;
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see java.lang.Iterable#iterator()
      */
     public Iterator<Column> iterator() {
         return getColumns().iterator();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getColumnNames()
      */
     public List<String> getColumnNames() {
         return columnNames;
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getColumnCount()
      */
     public int getColumnCount() {
         return columns.size();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getLocationCount()
      */
     public int getLocationCount() {
         return selectorNames.size();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getSelectorNames()
      */
     public List<String> getSelectorNames() {
         return selectorNames;
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getTupleSize()
      */
     public int getTupleSize() {
         return tupleSize;
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getTupleValueNames()
      */
     public List<String> getTupleValueNames() {
         if (this.tupleValueNames == null) {
             // This is idempotent, so no need to lock ...
             List<String> results = new ArrayList<String>(getTupleSize());
             // Add the column names ...
             results.addAll(columnNames);
             // Add the location names ...
             for (String selectorName : selectorNames) {
                 String name = "Location(" + selectorName + ")";
                 results.add(name);
             }
             // Add the full-text search score names ...
             if (fullTextSearchScoreIndexBySelectorName != null) {
                 for (String selectorName : selectorNames) {
                     String name = "Score(" + selectorName + ")";
                     results.add(name);
                 }
             }
             this.tupleValueNames = results;
         }
         return this.tupleValueNames;
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getLocationIndexForColumn(int)
      */
     public int getLocationIndexForColumn( int columnIndex ) {
         if (locationIndexByColumnIndex.isEmpty()) return 0;
         Integer result = locationIndexByColumnIndex.get(new Integer(columnIndex));
         if (result == null) {
             throw new IndexOutOfBoundsException(GraphI18n.columnDoesNotExistInQuery.text(columnIndex));
         }
         return result.intValue();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getLocationIndexForColumn(java.lang.String)
      */
     public int getLocationIndexForColumn( String columnName ) {
         if (locationIndexByColumnName.isEmpty()) return 0;
         Integer result = locationIndexByColumnName.get(columnName);
         if (result == null) {
             throw new NoSuchElementException(GraphI18n.columnDoesNotExistInQuery.text(columnName));
         }
         return result.intValue();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getLocationIndex(java.lang.String)
      */
     public int getLocationIndex( String selectorName ) {
         Integer result = locationIndexBySelectorName.get(selectorName);
         if (result == null) {
             throw new NoSuchElementException(GraphI18n.selectorDoesNotExistInQuery.text(selectorName));
         }
         return result.intValue();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#hasSelector(java.lang.String)
      */
     public boolean hasSelector( String selectorName ) {
         return locationIndexBySelectorName.containsKey(selectorName);
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getPropertyNameForColumn(int)
      */
     public String getPropertyNameForColumn( int columnIndex ) {
         return columns.get(columnIndex).getPropertyName();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getPropertyNameForColumn(java.lang.String)
      */
     public String getPropertyNameForColumn( String columnName ) {
         Column result = columnsByName.get(columnName);
         if (result == null) {
             throw new NoSuchElementException(GraphI18n.columnDoesNotExistInQuery.text(columnName));
         }
         return result.getPropertyName();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getColumnIndexForName(java.lang.String)
      */
     public int getColumnIndexForName( String columnName ) {
         Integer result = columnIndexByColumnName.get(columnName);
         if (result == null) {
             throw new NoSuchElementException(GraphI18n.columnDoesNotExistInQuery.text(columnName));
         }
         return result.intValue();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getColumnIndexForProperty(java.lang.String, java.lang.String)
      */
     public int getColumnIndexForProperty( String selectorName,
                                           String propertyName ) {
         Map<String, Integer> byPropertyName = columnIndexByPropertyNameBySelectorName.get(selectorName);
         if (byPropertyName == null) {
             throw new NoSuchElementException(GraphI18n.selectorDoesNotExistInQuery.text(selectorName));
         }
         Integer result = byPropertyName.get(propertyName);
         if (result == null) {
             throw new NoSuchElementException(GraphI18n.propertyOnSelectorIsNotUsedInQuery.text(propertyName, selectorName));
         }
         return result.intValue();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#getFullTextSearchScoreIndexFor(java.lang.String)
      */
     public int getFullTextSearchScoreIndexFor( String selectorName ) {
         if (fullTextSearchScoreIndexBySelectorName == null) return -1;
         Integer result = fullTextSearchScoreIndexBySelectorName.get(selectorName);
         if (result == null) {
             throw new NoSuchElementException(GraphI18n.selectorDoesNotExistInQuery.text(selectorName));
         }
         return result.intValue();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#hasFullTextSearchScores()
      */
     public boolean hasFullTextSearchScores() {
         return fullTextSearchScoreIndexBySelectorName != null;
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#includes(org.modeshape.graph.query.QueryResults.Columns)
      */
     public boolean includes( Columns other ) {
         if (other == this) return true;
         if (other == null) return false;
         return this.getColumns().containsAll(other.getColumns());
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see org.modeshape.graph.query.QueryResults.Columns#isUnionCompatible(org.modeshape.graph.query.QueryResults.Columns)
      */
     public boolean isUnionCompatible( Columns other ) {
         if (this == other) return true;
         if (other == null) return false;
         if (this.hasFullTextSearchScores() != other.hasFullTextSearchScores()) return false;
         if (this.getColumnCount() != other.getColumnCount()) return false;
         return this.getColumns().containsAll(other.getColumns()) && other.getColumns().containsAll(this.getColumns());
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see java.lang.Object#equals(java.lang.Object)
      */
     @Override
     public boolean equals( Object obj ) {
         if (obj == this) return true;
         if (obj instanceof QueryResultColumns) {
             QueryResultColumns that = (QueryResultColumns)obj;
             return this.getColumns().equals(that.getColumns());
         }
         return false;
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see java.lang.Object#toString()
      */
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder();
         sb.append(" [");
         boolean first = true;
         for (Column column : getColumns()) {
             if (first) first = false;
             else sb.append(", ");
             sb.append(column);
         }
         sb.append("] => Locations[");
         first = true;
         for (int i = 0, count = getColumnCount(); i != count; ++i) {
             if (first) first = false;
             else sb.append(", ");
             sb.append(getLocationIndexForColumn(i));
         }
         sb.append(']');
         return sb.toString();
     }
 }