EDIT

/**

* Copyright (C) 2017 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.vaadin.component;

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

import org.apache.log4j.Logger;

import com.vaadin.data.Property;

import com.vaadin.data.Validator.InvalidValueException;

import com.vaadin.data.fieldgroup.FieldGroup;

import com.vaadin.server.FontAwesome;

import com.vaadin.ui.AbstractField;

import com.vaadin.ui.Button;

import com.vaadin.ui.Button.ClickListener;

import com.vaadin.ui.Component;

import com.vaadin.ui.CssLayout;

import com.vaadin.ui.Field;

import com.vaadin.ui.GridLayout;

import com.vaadin.ui.themes.ValoTheme;

/**

 * Manages the a collection of items internally as LinkedList<V>. If the Collection to operate on is a Set a Converter must be

 * set. Internally used fields are used in un-buffered mode.

 *

 * @author a.kohlbecker

 * @since May 11, 2017

 *

 */

public class ToManyRelatedEntitiesListSelect<V extends Object, F extends AbstractField<V>>  extends CompositeCustomField<List<V>> {

    private static final long serialVersionUID = 4670707714503199599L;

    private static final Logger logger = Logger.getLogger(ToManyRelatedEntitiesListSelect.class);

    protected Class<F> fieldType;

    protected Class<V> itemType;

    private FieldGroup parentFieldGroup = null;

    protected boolean isOrderedCollection = false;

    private boolean withEditButton = false;

    private static final int GRID_X_FIELD = 0;

    protected boolean addEmptyRowOnInitContent = true;

    private int GRID_COLS = 2;

    private GridLayout grid = new GridLayout(GRID_COLS, 1);

    public  ToManyRelatedEntitiesListSelect(Class<V> itemType, Class<F> fieldType, String caption){

        this.fieldType = fieldType;

        this.itemType = itemType;

        setCaption(caption);

    }

    /**

     * @param field

     * @return

     */

    protected Integer findRow(F field) {

        Integer row = null;

        for(int r = 0; r < grid.getRows(); r++){

            if(grid.getComponent(GRID_X_FIELD, r).equals(field)){

                row = r;

                break;

            }

        }

        return row;

    }

    /**

     * @param field

     * @return

     */

    private void addRowAfter(F field) {

        Integer row = findRow(field);

        grid.insertRow(row + 1);

        // setting null as value for new rows

        // see newFieldInstance() !!!

        addNewRow(row + 1, null);

        updateValue();

    }

    /**

     * @param field

     * @return

     */

    private void removeRow(F field) {

        Integer row = findRow(field);

        grid.removeRow(row);

        // TODO remove from nested fields

        updateValue();

        updateButtonStates();

    }

    /**

     * @param field

     * @return

     */

    private void moveRowDown(F field) {

        Integer row = findRow(field);

        swapRows(row);

    }

    /**

     * @param field

     * @return

     */

    private void moveRowUp(F field) {

        Integer row = findRow(field);

        swapRows(row - 1);

    }

    /**

     * @param i

     */

    private void swapRows(int i) {

        if(i >= 0 && i + 1 < grid.getRows()){

            grid.replaceComponent(grid.getComponent(GRID_X_FIELD, i), grid.getComponent(GRID_X_FIELD, i + 1));

            grid.replaceComponent(grid.getComponent(GRID_X_FIELD  + 1 , i), grid.getComponent(GRID_X_FIELD + 1, i + 1));

            updateButtonStates();

            updateValue();

        } else {

            throw new RuntimeException("Cannot swap rows out of the grid bounds");

        }

    }

    /**

     *

     */

    protected void updateValue() {

        List<V> nestedValues = getValueFromNestedFields();

        List<V> beanList = getValue();

        beanList.clear();

        beanList.addAll(nestedValues);

        setInternalValue(beanList);

    }

    /**

     * @param field

     * @return

     */

    protected ClickListener newEditButtonClicklistener(F field) {

        return null;

    }

    /**

     * @return

     */

    protected ClickListener newAddButtonClicklistener(F field) {

        return null;

    }

    /**

     * @return

     */

    protected ClickListener newRemoveButtonClicklistener(F field) {

        return null;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    protected Component initContent() {

        grid.setColumnExpandRatio(0, 1.0f);

        // set internal value to null to add an empty row

        if(addEmptyRowOnInitContent){

            // add an empty row

            setInternalValue(null);

        }

        return grid;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public Class getType() {

        return List.class;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    protected void setInternalValue(List<V> newValue) {

         grid.removeAllComponents();

         grid.setRows(1);

        if(newValue != null){

            super.setInternalValue(newValue);

            // newValue is already converted, need to use the original value from the data source

            isOrderedCollection = List.class.isAssignableFrom(getPropertyDataSource().getValue().getClass());

            int row = 0;

            if(newValue.size() > 0){

                for(V val : newValue){

                    row = addNewRow(row, val);

                }

            }

        }

        if(newValue == null || newValue.isEmpty()) {

            // add an empty row

            addNewRow(0, null);

        }

    }

    /**

     * @param row

     * @param val

     * @return

     */

    protected int addNewRow(int row, V val) {

        try {

            F field = newFieldInstance(val);

            Property ds = getPropertyDataSource();

            if(ds != null){

                Object parentVal = ds.getValue();

            }

            addStyledComponent(field);

            // important! all fields must be un-buffered

            field.setBuffered(false);

            if(getNestedFields().size() == grid.getRows()){

                grid.setRows(grid.getRows() + 1);

            }

            grid.addComponent(field, GRID_X_FIELD, row);

            grid.addComponent(buttonGroup(field), 1, row);

            updateButtonStates();

            nestFieldGroup(field);

            row++;

        } catch (InstantiationException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        } catch (IllegalAccessException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

        return row;

    }

    private Component buttonGroup(F field){

        CssLayout buttonGroup = new CssLayout();

        Button add = new Button(FontAwesome.PLUS);

        add.setDescription("Add item");

        add.addClickListener(e -> addRowAfter(field));

        if(withEditButton){

            Button edit = new Button(FontAwesome.EDIT);

            ClickListener editClickListerner = newEditButtonClicklistener(field);

            if(editClickListerner != null){

                edit.addClickListener(editClickListerner);

            }

            buttonGroup.addComponent(edit);

            addStyledComponents(edit);

        }

        Button remove = new Button(FontAwesome.MINUS);

        remove.setDescription("Remove item");

        remove.addClickListener(e -> removeRow(field));

        buttonGroup.addComponent(add);

        buttonGroup.addComponent(remove);

        addStyledComponents(add, remove);

        if(isOrderedCollection){

            Button moveUp = new Button(FontAwesome.ARROW_UP);

            moveUp.setDescription("Move up");

            moveUp.addClickListener(e -> moveRowUp(field));

            Button moveDown = new Button(FontAwesome.ARROW_DOWN);

            moveDown.addClickListener(e -> moveRowDown(field));

            moveDown.setDescription("Move down");

            buttonGroup.addComponents(moveUp, moveDown);

            addStyledComponents(moveUp, moveDown);

        }

        buttonGroup.setStyleName(ValoTheme.LAYOUT_COMPONENT_GROUP);

        return buttonGroup;

    }

    private void updateButtonStates(){

        int fieldsCount = getNestedFields().size();

        for(int row = 0; row < fieldsCount; row++){

            boolean isFirst = row == 0;

            boolean isLast = row == fieldsCount - 1;

            CssLayout buttonGroup = (CssLayout) grid.getComponent(GRID_X_FIELD + 1, row);

            // add

            buttonGroup.getComponent(0).setEnabled(isLast || isOrderedCollection);

            // remove

            buttonGroup.getComponent(1).setEnabled(!isFirst);

            // up

            if(buttonGroup.getComponentCount() > 2){

                buttonGroup.getComponent(2).setEnabled(!isFirst);

                // down

                buttonGroup.getComponent(3).setEnabled(!isLast);

            }

        }

    }

    protected List<F> getNestedFields(){

        List<F> nestedFields = new ArrayList<>(grid.getRows());

        for(int r = 0; r < grid.getRows(); r++){

            F f = (F) grid.getComponent(GRID_X_FIELD, r);

            if(f == null){

                logger.debug(String.format("NULL field at %d,%d", GRID_X_FIELD, r));

            } else {

                nestedFields.add(f);

            }

        }

        return Collections.unmodifiableList(nestedFields);

    }

    /**

     *

     * @param val

     * @return

     * @throws InstantiationException

     * @throws IllegalAccessException

     */

    protected F newFieldInstance(V val) throws InstantiationException, IllegalAccessException {

        F field = fieldType.newInstance();

        field.setWidth(100, Unit.PERCENTAGE);

        field.setValue(val);

        // TODO

        // when passing null as value the field must take care of creating a new

        // instance by overriding setValue() in future we could improve this by passing a

        // NewInstanceFactory to this class

        return field;

    }

    /**

     * Handle the data binding of the sub fields. Sub-fields can either be composite editor fields

     * or 'simple' fields, usually select fields.

     * <p>

     * Composite editor fields allow editing the nested bean Items and must implement the

     * {@link NestedFieldGroup} interface. Simple fields are only instantiated in

     * {@link #newFieldInstance(Object)} where the value of the field is set. No further binding is needed

     * for these 'simple' fields.

     *

     * @param field

     */

    protected void nestFieldGroup(F field) {

        if(NestedFieldGroup.class.isAssignableFrom(fieldType) && parentFieldGroup != null){

            ((NestedFieldGroup)field).registerParentFieldGroup(parentFieldGroup);

        }

    }

    /**

     * {@inheritDoc}

     * <p>

     * However, this class has no local fieldGroup but must delegate to the nested NestedFieldGroup

     * if there are any. This happens in {@link #nestFieldGroup(AbstractField)}.

     * <p>

     */

    @Override

    public FieldGroup getFieldGroup() {

        return null;

    }

    /**

     * This ToMany-CompositeCustomField has no own fields and this no local fieldGroup (see {@link #getFieldGroup()})

     * which allow changing data. Editing of the list items is delegated to

     * a list of sub-fields which are responsible for editing and committing the changes.

     * Therefore the <code>parentFieldGroup</code> is only stored in a local field so that it can

     * be passed to per item fields in {@link #nestFieldGroup}

     *

     * {@inheritDoc}

     */

    @Override

    public void registerParentFieldGroup(FieldGroup parent) {

        parentFieldGroup = parent;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public void commit() throws SourceException, InvalidValueException {

        List<F> nestedFields = getNestedFields();

        for(F f : nestedFields){

            f.commit();

        }

        // calling super.commit() is useless if operating on a transient property!!

        super.commit();

    }

    /**

     * Obtains the List of values directly from the nested fields and ignores the

     * value of the <code>propertyDataSource</code>. This is useful when the ToManyRelatedEntitiesListSelect

     * is operating on a transient field, in which case the property is considered being read only by vaadin

     * so that the commit is doing nothing.

     *

     * See also {@link AbstractCdmEditorPresenter#handleTransientProperties(DTO bean)}

     *

     * @return

     */

    public List<V> getValueFromNestedFields() {

        List<V> nestedValues = new ArrayList<>();

        for(F f : getNestedFields()) {

            logger.trace(

                    String.format("getValueFromNestedFields() - %s:%s",

                       f != null ? f.getClass().getSimpleName() : "null",

                       f != null && f.getValue() != null ? f.getValue() : "null"

            ));

            V value = f.getValue();

            if(f != null && value != null){

                nestedValues.add(f.getValue());

            }

         }

        return nestedValues;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public void setWidth(String width) {

        super.setWidth(width);

        grid.setWidth(width);

    }

    @Override

    public void setWidth(float width, Unit unit){

        super.setWidth(width, unit);

        if(grid != null){

            grid.setWidth(width, unit);

        }

    }

    /**

     * {@inheritDoc}

     */

    @Override

    protected void addDefaultStyles() {

        // no default styles

    }

    public void withEditButton(boolean withEditButton){

        this.withEditButton = withEditButton;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public boolean hasNullContent() {

        for(Field f : getNestedFields()){

            if(f instanceof CompositeCustomField){

                if(!((CompositeCustomField)f).hasNullContent()){

                    return false;

                }

            }

        }

        return true;

    }

}