/*
Copyright (c) 2011 James Ahlborn

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.healthmarketscience.jackcess.impl.complex;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import com.healthmarketscience.jackcess.Column;
import com.healthmarketscience.jackcess.DataType;
import com.healthmarketscience.jackcess.Database;
import com.healthmarketscience.jackcess.IndexCursor;
import com.healthmarketscience.jackcess.Row;
import com.healthmarketscience.jackcess.RowId;
import com.healthmarketscience.jackcess.RuntimeIOException;
import com.healthmarketscience.jackcess.Table;
import com.healthmarketscience.jackcess.complex.ComplexColumnInfo;
import com.healthmarketscience.jackcess.complex.ComplexDataType;
import com.healthmarketscience.jackcess.complex.ComplexValue;
import com.healthmarketscience.jackcess.complex.ComplexValueForeignKey;
import com.healthmarketscience.jackcess.impl.ColumnImpl;
import com.healthmarketscience.jackcess.impl.CustomToStringStyle;
import com.healthmarketscience.jackcess.impl.TableImpl;

/**
 * Base class for the additional information tracked for complex columns.
 *
 * @author James Ahlborn
 */
public abstract class ComplexColumnInfoImpl<V extends ComplexValue> 
  implements ComplexColumnInfo<V>
{
  private static final int INVALID_ID_VALUE = -1;
  public static final ComplexValue.Id INVALID_ID = new ComplexValueIdImpl(
      INVALID_ID_VALUE, null);
  public static final ComplexValueForeignKey INVALID_FK =
    new ComplexValueForeignKeyImpl(null, INVALID_ID_VALUE);

  private final Column _column;
  private final int _complexTypeId;
  private final Table _flatTable;
  private final List<Column> _typeCols;
  private final Column _pkCol;
  private final Column _complexValFkCol;
  private IndexCursor _complexValIdCursor;
  
  protected ComplexColumnInfoImpl(Column column, int complexTypeId,
                                  Table typeObjTable, Table flatTable)
    throws IOException
  {
    _column = column;
    _complexTypeId = complexTypeId;
    _flatTable = flatTable;
    
    // the flat table has all the "value" columns and 2 extra columns, a
    // primary key for each row, and a LONG value which is essentially a
    // foreign key to the main table.
    List<Column> typeCols = new ArrayList<Column>();
    List<Column> otherCols = new ArrayList<Column>();
    diffFlatColumns(typeObjTable, flatTable, typeCols, otherCols);

    _typeCols = Collections.unmodifiableList(typeCols);

    Column pkCol = null;
    Column complexValFkCol = null;
    for(Column col : otherCols) {
      if(col.isAutoNumber()) {
        pkCol = col;
      } else if(col.getType() == DataType.LONG) {
        complexValFkCol = col;
      }
    }

    if((pkCol == null) || (complexValFkCol == null)) {
      throw new IOException("Could not find expected columns in flat table " +
                            flatTable.getName() + " for complex column with id "
                            + complexTypeId);
    }
    _pkCol = pkCol;
    _complexValFkCol = complexValFkCol;
  }

  public void postTableLoadInit() throws IOException {
    // nothing to do in base class
  }
  
  public Column getColumn() {
    return _column;
  }

  public Database getDatabase() {
    return getColumn().getDatabase();
  }

  public Column getPrimaryKeyColumn() {
    return _pkCol;
  }

  public Column getComplexValueForeignKeyColumn() {
    return _complexValFkCol;
  }

  protected List<Column> getTypeColumns() {
    return _typeCols;
  }
  
  @Override
  public int countValues(int complexValueFk) throws IOException {
    return getRawValues(complexValueFk,
                        Collections.singleton(_complexValFkCol.getName()))
      .size();
  }
  
  @Override
  public List<Row> getRawValues(int complexValueFk)
    throws IOException
  {
    return getRawValues(complexValueFk, null);
  }

  private Iterator<Row> getComplexValFkIter(
      int complexValueFk, Collection<String> columnNames)
    throws IOException
  {
    if(_complexValIdCursor == null) {
      _complexValIdCursor = _flatTable.newCursor()
        .setIndexByColumns(_complexValFkCol)
        .toIndexCursor();
    }

    return _complexValIdCursor.newEntryIterable(complexValueFk)
      .setColumnNames(columnNames).iterator();
  }
  
  @Override
  public List<Row> getRawValues(int complexValueFk,
                                Collection<String> columnNames)
    throws IOException
  {
    Iterator<Row> entryIter =
      getComplexValFkIter(complexValueFk, columnNames);
    if(!entryIter.hasNext()) {
      return Collections.emptyList();
    }

    List<Row> values = new ArrayList<Row>();
    while(entryIter.hasNext()) {
      values.add(entryIter.next());
    }
    
    return values;
  }

  @Override
  public List<V> getValues(ComplexValueForeignKey complexValueFk)
    throws IOException
  {
    List<Row> rawValues = getRawValues(complexValueFk.get());
    if(rawValues.isEmpty()) {
      return Collections.emptyList();
    }

    return toValues(complexValueFk, rawValues);
  }
  
  protected List<V> toValues(ComplexValueForeignKey complexValueFk,
                             List<Row> rawValues)
    throws IOException
  {
    List<V> values = new ArrayList<V>();
    for(Row rawValue : rawValues) {
      values.add(toValue(complexValueFk, rawValue));
    }

    return values;
  }

  @Override
  public ComplexValue.Id addRawValue(Map<String,?> rawValue)
    throws IOException 
  {
    Object[] row = ((TableImpl)_flatTable).asRowWithRowId(rawValue);
    _flatTable.addRow(row);
    return getValueId(row);
  }

  @Override
  public ComplexValue.Id addValue(V value) throws IOException {
    Object[] row = asRow(newRowArray(), value);
    _flatTable.addRow(row);
    ComplexValue.Id id = getValueId(row);
    value.setId(id);
    return id;
  }

  @Override
  public void addValues(Collection<? extends V> values) throws IOException {
    for(V value : values) {
      addValue(value);
    }
  }

  @Override
  public ComplexValue.Id updateRawValue(Row rawValue) throws IOException {
    _flatTable.updateRow(rawValue);
    return getValueId(rawValue);
  }
  
  @Override
  public ComplexValue.Id updateValue(V value) throws IOException {
    ComplexValue.Id id = value.getId();
    updateRow(id, asRow(newRowArray(), value));
    return id;
  }

  @Override
  public void updateValues(Collection<? extends V> values) throws IOException {
    for(V value : values) {
      updateValue(value);
    }
  }

  @Override
  public void deleteRawValue(Row rawValue) throws IOException {
    deleteRow(rawValue.getId());
  }
  
  @Override
  public void deleteValue(V value) throws IOException {
    deleteRow(value.getId().getRowId());
  }

  @Override
  public void deleteValues(Collection<? extends V> values) throws IOException {
    for(V value : values) {
      deleteValue(value);
    }
  }

  @Override
  public void deleteAllValues(int complexValueFk) throws IOException {
    Iterator<Row> entryIter =
      getComplexValFkIter(complexValueFk, Collections.<String>emptySet());
    try {
      while(entryIter.hasNext()) {
        entryIter.next();
        entryIter.remove();
      }
    } catch(RuntimeIOException e) {
      throw (IOException)e.getCause();
    }
  }

  @Override
  public void deleteAllValues(ComplexValueForeignKey complexValueFk)
    throws IOException
  {
    deleteAllValues(complexValueFk.get());
  }

  private void updateRow(ComplexValue.Id id, Object[] row) throws IOException {
    ((TableImpl)_flatTable).updateRow(id.getRowId(), row);
  }
  
  private void deleteRow(RowId rowId) throws IOException {
    ((TableImpl)_flatTable).deleteRow(rowId);
  }
  
  protected ComplexValueIdImpl getValueId(Row row) {
    int idVal = (Integer)getPrimaryKeyColumn().getRowValue(row);
    return new ComplexValueIdImpl(idVal, row.getId());
  }

  protected ComplexValueIdImpl getValueId(Object[] row) {
    int idVal = (Integer)getPrimaryKeyColumn().getRowValue(row);
    return new ComplexValueIdImpl(idVal, 
                                  ((TableImpl)_flatTable).getRowId(row));
  }

  protected Object[] asRow(Object[] row, V value) 
    throws IOException
  {
  ComplexValue.Id id = value.getId();
    _pkCol.setRowValue(
        row, ((id != INVALID_ID) ? id : Column.AUTO_NUMBER));
    ComplexValueForeignKey cFk = value.getComplexValueForeignKey();
    _complexValFkCol.setRowValue(
        row, ((cFk != INVALID_FK) ? cFk : Column.AUTO_NUMBER));
    return row;
  }

  private Object[] newRowArray() {
    Object[] row = new Object[_flatTable.getColumnCount() + 1];
    row[row.length - 1] = ColumnImpl.RETURN_ROW_ID;
    return row;
  }
  
  @Override
  public String toString() {
    return CustomToStringStyle.valueBuilder(this)
      .append("complexType", getType())
      .append("complexTypeId", _complexTypeId)
      .toString();
  }

  protected static void diffFlatColumns(Table typeObjTable, 
                                        Table flatTable,
                                        List<Column> typeCols,
                                        List<Column> otherCols)
  {
    // each "flat"" table has the columns from the "type" table, plus some
    // others.  separate the "flat" columns into these 2 buckets
    for(Column col : flatTable.getColumns()) {
      if(((TableImpl)typeObjTable).hasColumn(col.getName())) {
        typeCols.add(col);
      } else {
        otherCols.add(col);
      }  
    } 
  }
  
  @Override
  public abstract ComplexDataType getType();

  protected abstract V toValue(
      ComplexValueForeignKey complexValueFk,
      Row rawValues)
    throws IOException;
  
  protected static abstract class ComplexValueImpl implements ComplexValue
  {
    private Id _id;
    private ComplexValueForeignKey _complexValueFk;

    protected ComplexValueImpl(Id id, ComplexValueForeignKey complexValueFk) {
      _id = id;
      _complexValueFk = complexValueFk;
    }

    @Override
    public Id getId() {
      return _id;
    }

    @Override
    public void setId(Id id) {
      if(_id == id) {
        // harmless, ignore
        return;
      }
      if(_id != INVALID_ID) {
        throw new IllegalStateException("id may not be reset");
      }
      _id = id;
    }
    
    @Override
    public ComplexValueForeignKey getComplexValueForeignKey() {
      return _complexValueFk;
    }

    @Override
    public void setComplexValueForeignKey(ComplexValueForeignKey complexValueFk)
    {
      if(_complexValueFk == complexValueFk) {
        // harmless, ignore
        return;
      }
      if(_complexValueFk != INVALID_FK) {
        throw new IllegalStateException("complexValueFk may not be reset");
      }
      _complexValueFk = complexValueFk;
    }

    @Override
    public Column getColumn() {
      return _complexValueFk.getColumn();
    }
    
    @Override
    public int hashCode() {
      return ((_id.get() * 37) ^ _complexValueFk.hashCode());
    }

    @Override
    public boolean equals(Object o) {
      return ((this == o) ||
              ((o != null) && (getClass() == o.getClass()) &&
               (_id == ((ComplexValueImpl)o)._id) &&
               _complexValueFk.equals(((ComplexValueImpl)o)._complexValueFk)));
    }
  }

  /**
   * Implementation of ComplexValue.Id.
   */
  private static final class ComplexValueIdImpl extends ComplexValue.Id
  {
    private static final long serialVersionUID = 20130318L;    

    private final int _value;
    private final RowId _rowId;

    protected ComplexValueIdImpl(int value, RowId rowId) {
      _value = value;
      _rowId = rowId;
    }
    
    @Override
    public int get() {
      return _value;
    }

    @Override
    public RowId getRowId() {
      return _rowId;
    }
  }
  
}