/*
 * Copyright 2015 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * 
 *      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.drools.workbench.models.testscenarios.backend.util;

import java.security.InvalidParameterException;
import java.util.ArrayList;

import org.drools.workbench.models.testscenarios.shared.*;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.converters.reflection.ReflectionConverter;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;

public class FieldConverter implements Converter {


    private final XStream xt;

    public FieldConverter(XStream xt) {
        this.xt = xt;
    }

    @Override
    public void marshal(Object source, HierarchicalStreamWriter writer, MarshallingContext context) {
        context.convertAnother(source, getDefaultConverter());
    }

    @Override
    public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {

        reader.moveDown();
        String name = reader.getValue();
        reader.moveUp();

        if (!reader.hasMoreChildren()) {

            return new FieldPlaceHolder(name);

        } else {
            reader.moveDown();

            if (reader.getNodeName().equals("collectionFieldList")) {

                CollectionFieldData collectionFieldData = createCollectionFieldData(context, name);
                reader.moveUp();

                return collectionFieldData;

            } else if (reader.getNodeName().equals("value")) {
                return createFieldData(reader, context, name);

            } else if (reader.getNodeName().equals("fact")) {

                FactAssignmentField factAssignmentField = new FactAssignmentField();
                factAssignmentField.setName(name);

                factAssignmentField.setFact((Fact) context.convertAnother(factAssignmentField, Fact.class));
                reader.moveUp();

                return factAssignmentField;
            }
        }

        throw new InvalidParameterException("Unknown Field instance.");
    }

    private Object createFieldData(HierarchicalStreamReader reader, UnmarshallingContext context, String name) {
        FieldData fieldData = new FieldData();

        fieldData.setName(name);

        fieldData.setValue(reader.getValue());
        reader.moveUp();

        // Nature is optional
        if (reader.hasMoreChildren()) {
            reader.moveDown();
            String value = reader.getValue();
            fieldData.setNature(Integer.parseInt(value));
            reader.moveUp();
        }

        // Could be a legacy CollectionFieldData, let's see
        if (reader.hasMoreChildren()) {
            reader.moveDown();
            if (reader.getNodeName().equals("collectionFieldList")) {
                CollectionFieldData collectionFieldData = createCollectionFieldData(context, name);
                reader.moveUp();

                if (!collectionFieldData.getCollectionFieldList().isEmpty()) {
                    return collectionFieldData;
                }
            }
        }
        // And since we have a big big big pile of legacy test scenarios with a marvelous design
        // we do one more check if this field data is after all a collection field data!
        if (fieldData.getValue() != null && fieldData.getValue().startsWith("=[")) {
            CollectionFieldData collectionFieldData = new CollectionFieldData();
            collectionFieldData.setName(name);

            String list = fieldData.getValue().substring(2, fieldData.getValue().length() - 1);

            if (list.contains(",")) {
                for (String value : list.split(",")) {
                    FieldData subFieldData = new FieldData();
                    subFieldData.setName(name);
                    subFieldData.setValue(value);
                    collectionFieldData.getCollectionFieldList().add(subFieldData);
                }
            } else {
                FieldData subFieldData = new FieldData();
                subFieldData.setName(name);
                subFieldData.setValue(list);
                collectionFieldData.getCollectionFieldList().add(subFieldData);
            }

            return collectionFieldData;
        } else {
            return fieldData;
        }
    }

    private CollectionFieldData createCollectionFieldData(UnmarshallingContext context, String name) {
        CollectionFieldData collectionFieldData = new CollectionFieldData();
        collectionFieldData.setName(name);

        collectionFieldData.setCollectionFieldList((ArrayList) context.convertAnother(collectionFieldData, ArrayList.class));
        return collectionFieldData;
    }

    @Override
    public boolean canConvert(Class type) {
        return Field.class.isAssignableFrom(type);
    }


    private ReflectionConverter getDefaultConverter() {
        return new ReflectionConverter(xt.getMapper(), xt.getReflectionProvider());
    }

}