/*
 * 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.tuscany.das.rdb.impl;

import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.log4j.Logger;
import org.apache.tuscany.das.rdb.Command;
import org.apache.tuscany.das.rdb.config.Column;
import org.apache.tuscany.das.rdb.config.Relationship;
import org.apache.tuscany.das.rdb.config.Table;
import org.apache.tuscany.das.rdb.config.wrapper.MappingWrapper;
import org.apache.tuscany.das.rdb.config.wrapper.RelationshipWrapper;
import org.apache.tuscany.das.rdb.config.wrapper.TableWrapper;
import org.apache.tuscany.das.rdb.util.CollectionsUtil;
import org.apache.tuscany.sdo.impl.ChangeSummaryImpl;

import commonj.sdo.ChangeSummary;
import commonj.sdo.DataObject;
import commonj.sdo.Property;
import commonj.sdo.Type;

public class ChangeSummarizer {

    private final Logger logger = Logger.getLogger(ChangeSummarizer.class);

    private Changes changes = new Changes();

    private FactoryRegistry registry;

    private MappingWrapper mapping = new MappingWrapper();

    private ConnectionImpl connection;

    private Map generatedKeys = new HashMap();

    public ChangeSummarizer() {
        // Empty Constructor
    }

    public Changes loadChanges(DataObject root) {
        ChangeSummary changeSummary = root.getDataGraph().getChangeSummary();
        if (changeSummary.isLogging()) {
            ((ChangeSummaryImpl) changeSummary).summarize();
        }

        List changedObjects = changeSummary.getChangedDataObjects();

        if (this.logger.isDebugEnabled()) {
            this.logger.debug("List of changed objects contains " + changedObjects.size() + " object(s)");
        }

        changes.setInsertOrder(mapping.getInsertOrder());
        changes.setDeleteOrder(mapping.getDeleteOrder());

        Iterator i = changedObjects.iterator();
        while (i.hasNext()) {
            DataObject o = (DataObject) i.next();

            if (!(o.equals(root))) {
                createChange(changeSummary, o);
            }
        }

        return changes;
    }

    public void createChange(ChangeSummary changeSummary, DataObject changedObject) {

        if (changeSummary.isCreated(changedObject)) {
            if (this.logger.isDebugEnabled()) {
                this.logger.debug("Change is a create");
            }
            if (!changeSummary.isDeleted(changedObject)) {
                ChangeFactory factory = getRegistry().getFactory(changedObject.getType());
                String propagatedID = (String) generatedKeys.get(changedObject.getType().getName());
                changes.addInsert(factory.createInsertOperation(changedObject, propagatedID));
            }
        } else if (changeSummary.isDeleted(changedObject)) {
            ChangeFactory factory = getRegistry().getFactory(changedObject.getType());
            if (this.logger.isDebugEnabled()) {
                this.logger.debug("Change is a delete");
            }
            changes.addDelete(factory.createDeleteOperation(changedObject));
        } else {
            if (this.logger.isDebugEnabled()) {
                this.logger.debug("Change is a modify");
            }
            List attrList = changeSummary.getOldValues(changedObject);
            if (hasAttributeChange(attrList)) {
                ChangeFactory factory = getRegistry().getFactory(changedObject.getType());
                if (this.logger.isDebugEnabled()) {
                    this.logger.debug("Attribute Change for " + changedObject.getType().getName());
                }
                String propagatedID = (String) generatedKeys.get(changedObject.getType().getName());
                changes.addUpdate(factory.createUpdateOperation(changedObject, propagatedID));
            } else {
                List values = changeSummary.getOldValues(changedObject);
                Iterator i = values.iterator();
                while (i.hasNext()) {
                    ChangeSummary.Setting setting = (ChangeSummary.Setting) i.next();
                    if (!setting.getProperty().getType().isDataType()) {
                        if (this.logger.isDebugEnabled()) {
                            this.logger.debug("Reference change for " + changedObject.getType().getName());
                        }
                        Property ref = setting.getProperty();
                        if (this.logger.isDebugEnabled()) {
                            this.logger.debug(ref.getName());
                        }
                        if (hasState(ref, changedObject)) {
                            ChangeFactory factory = getRegistry().getFactory(changedObject.getType());
                            changes.addUpdate(factory.createUpdateOperation(changedObject));
                        }
                    }
                }
            }
        }

    }

    private boolean hasState(Property ref, DataObject changedObject) {
        if (ref.getOpposite().isMany()) {
            return true;
        } 

        MappingWrapper mw = this.mapping;
        if (mw.getConfig() == null) {
            mw = registry.getFactory(changedObject.getType()).getConfig();
        }
        if (mw.getConfig() == null) {
            return false;
        }

        Relationship rel = mw.getRelationshipByReference(ref);

        if (!rel.isMany()) {
            if (rel.isKeyRestricted()) {
                throw new RuntimeException("Can not modify a one to one relationship that is key restricted");
            }
            // This is a one-one relationship
            Table t = mapping.getTableByTypeName(changedObject.getType().getName());
            TableWrapper tw = new TableWrapper(t);
            RelationshipWrapper rw = new RelationshipWrapper(rel);
            if ((rel.getForeignKeyTable().equals(t.getTableName())) 
                    && (CollectionsUtil.disjoint(tw.getPrimaryKeyProperties(), rw.getForeignKeys()))) {
                return true;
            }

        }

        return false;
    }

    private boolean hasAttributeChange(List theChanges) {
        Iterator i = theChanges.iterator();
        while (i.hasNext()) {
            ChangeSummary.Setting setting = (ChangeSummary.Setting) i.next();
            if (setting.getProperty().getType().isDataType()) {
                return true;
            }
        }
        return false;
    }

    public void addCreateCommand(Type type, Command cmd) {
        ChangeFactory cf = getRegistry().getFactory(type);
        cf.setCreateCommand((InsertCommandImpl) cmd);
        ((CommandImpl) cmd).setConnection(connection);
    }

    public void addUpdateCommand(Type type, Command cmd) {
        ChangeFactory cf = getRegistry().getFactory(type);
        cf.setUpdateCommand((UpdateCommandImpl) cmd);
        ((CommandImpl) cmd).setConnection(connection);
    }

    public void addDeleteCommand(Type type, Command cmd) {
        ChangeFactory cf = getRegistry().getFactory(type);
        cf.setDeleteCommand((DeleteCommandImpl) cmd);
        ((CommandImpl) cmd).setConnection(connection);

    }

    private FactoryRegistry getRegistry() {
        if (this.registry == null) {
            this.registry = new FactoryRegistry(mapping, connection);
        }
        return this.registry;
    }

    public void setConnection(ConnectionImpl connection) {
        this.connection = connection;
    }

    public void setMapping(MappingWrapper map) {
        this.mapping = map;

        if (mapping.getConfig() == null) {
            return;
        }

        Iterator i = mapping.getConfig().getTable().iterator();
        while (i.hasNext()) {
            Table t = (Table) i.next();
            Iterator columns = t.getColumn().iterator();
            while (columns.hasNext()) {
                Column c = (Column) columns.next();
                if (c.isPrimaryKey() && c.isGenerated()) {
                    if (this.logger.isDebugEnabled()) {
                        this.logger.debug("adding generated key " + t.getTableName() + "." + c.getColumnName());
                    }

                    generatedKeys.put(t.getTableName(), c.getColumnName());
                }
            }
        }
    }

    public ConnectionImpl getConnection() {
        return this.connection;
    }
}