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.Arrays;

import java.util.Collections;

import java.util.HashSet;

import java.util.List;

import java.util.Optional;

import java.util.Set;

import org.apache.logging.log4j.LogManager;

import org.apache.logging.log4j.Logger;

import org.osgi.dto.DTO;

import com.vaadin.data.Property;

import com.vaadin.data.Validator;

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.Component;

import com.vaadin.ui.CssLayout;

import com.vaadin.ui.Field;

import com.vaadin.ui.GridLayout;

import com.vaadin.ui.themes.ValoTheme;

import eu.etaxonomy.cdm.vaadin.component.ButtonFactory;

import eu.etaxonomy.vaadin.event.EditorActionType;

import eu.etaxonomy.vaadin.event.EntityEditorActionEvent;

import eu.etaxonomy.vaadin.event.EntityEditorActionListener;

import eu.etaxonomy.vaadin.mvp.AbstractCdmEditorPresenter;

import eu.etaxonomy.vaadin.permission.EditPermissionTester;

/**

 * 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. The actual instances of the field type <code>F</code> to be used to

 * edit or select the entities is created by a implementation of the <code>EntityFieldInstantiator</code>,

 * see {@link #setEntityFieldInstantiator(EntityFieldInstantiator).

 *

 * @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 final static Logger logger = LogManager.getLogger();

    protected Class<F> fieldType;

    protected Class<V> itemType;

    private FieldGroup parentFieldGroup = null;

    private Boolean valueInitiallyWasNull = null;

    protected boolean isOrderedCollection = false;

    /**

     * with a button to edit existing and to add new entities

     */

    private boolean withEditButton = false;

    protected boolean addEmptyRowOnInitContent = true;

    private EntityFieldInstantiator<F> entityFieldInstantiator;

    private EditPermissionTester editPermissionTester;

    private EntityEditorActionListener editActionListener;

    /**

     * X index of the data field in the grid

     */

    private static final int GRID_X_FIELD = 0;

    private static final int GRID_X_BUTTON_GROUP = 1;

    private int GRID_COLS = 2;

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

    private boolean creatingFields;

    private List<Validator> fieldValidators = new ArrayList<>();

    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;

    }

    /**

     *

     * @return an unmodifiable List of the data Fields

     */

    protected List<F> fields() {

        Integer row = null;

        List<F> fields = new ArrayList<>();

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

            fields.add((F) grid.getComponent(GRID_X_FIELD, r));

        }

        return fields;

    }

    /**

     * @param field

     * @return

     */

    private void addRowAfter(F field) {

        List<V> nestedValues = getValueFromNestedFields();

        if(isOrderedCollection){

        } else {

        }

        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();

        updateComponentStates();

    }

    /**

     * @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));

            updateComponentStates();

            updateValue();

        } else {

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

        }

    }

    /**

     * update Value is only called in turn of UI changes like adding, removing, swapping rows

     */

    private void updateValue() {

        List<V> nestedValues = getValueFromNestedFields();

        List<V> beanList = getValue();

        if(beanList != null){

            beanList.clear();

            beanList.addAll(nestedValues);

        }

        setInternalValue(beanList);

    }

    /**

     * {@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) {

        super.setInternalValue(newValue);

        if(valueInitiallyWasNull == null){

            valueInitiallyWasNull = newValue == null;

        }

        if(newValue != null){

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

            boolean isListType = List.class.isAssignableFrom(getPropertyDataSource().getValue().getClass());

            // if(valueInitiallyWasNull && isOrderedCollection != isListType){

            if(valueInitiallyWasNull && isOrderedCollection != isListType){

                // need to reset the grid in this case, so that the button groups are created correctly

                clearRows();

            }

            isOrderedCollection = isListType;

        } else {

            clearRows();

        }

        if(!creatingFields){

            createFieldsForData();

        }

    }

    private void clearRows() {

        grid.removeAllComponents();

        grid.setRows(1);

    }

    private void createFieldsForData(){

        creatingFields = true;

        List<V> data = getValue();

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

            data = Arrays.asList((V)null);

        }

        for(int row = 0; row < data.size(); row++){

            boolean newRowNeeded = true;

            if(grid.getRows() > row){

                Component fieldComponent = grid.getComponent(GRID_X_FIELD, row);

                if(fieldComponent != null){

                    newRowNeeded = false;

                    F field = (F)fieldComponent;

                    if(data.get(row) != null && field.getValue() != data.get(row)){

                        boolean roState = field.isReadOnly();

                        field.setReadOnly(false);

                        field.setValue(data.get(row));

                        field.setReadOnly(roState);

                    }

                }

            }

            if(newRowNeeded){

                addNewRow(row, data.get(row));

            } else {

                // update the editOrCreate buttons

                ButtonGroup bg = (ToManyRelatedEntitiesListSelect<V, F>.ButtonGroup) grid.getComponent(GRID_X_BUTTON_GROUP, row);

                updateEditOrCreateButton(bg, data.get(row));

            }

        }

        creatingFields = false;

    }

    /**

     * 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;

    }

    /**

     * @param row the row index, starting from 0.

     * @param val

     * @return

     */

    protected int addNewRow(int row, V val) {

        try {

            F field = newFieldInstance(val);

            for(Validator validator : fieldValidators) {

                field.addValidator(validator);

            }

            ButtonGroup buttonGroup = new ButtonGroup(field);

            updateEditOrCreateButton(buttonGroup, val);

            field.addValueChangeListener(e -> {

                if(!creatingFields){

                    updateValue();

                    Object value = e.getProperty().getValue();

                    updateEditOrCreateButton(buttonGroup, value);

                    fireValueChange(true);

                }

            });

            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, GRID_X_BUTTON_GROUP, row);

            updateComponentStates();

            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;

    }

    /**

     * @param buttonGroup

     * @param value

     */

    public void updateEditOrCreateButton(ButtonGroup buttonGroup, Object value) {

        if(!withEditButton || buttonGroup == null || buttonGroup.getEditOrCreateButton() == null){

            return;

        }

        ButtonFactory buttonStyle;

        if(value == null){

            buttonStyle = ButtonFactory.CREATE_NEW;

        } else {

            buttonStyle = ButtonFactory.EDIT_ITEM;

        }

        buttonGroup.getEditOrCreateButton().setIcon(buttonStyle.getIcon());

        buttonGroup.getEditOrCreateButton().setDescription(buttonStyle.getDescription());

    }

    class ButtonGroup extends CssLayout{

        private Button editOrCreate;

        ButtonGroup (F field){

            Button add = ButtonFactory.ADD_ITEM.createButton();

            add.setDescription("Add item");

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

            if(withEditButton){

                editOrCreate = ButtonFactory.EDIT_ITEM.createButton();

                editOrCreate.addClickListener(e -> editOrCreate(field));

                addComponent(editOrCreate);

                addStyledComponents(editOrCreate);

            }

            Button remove = ButtonFactory.REMOVE_ITEM.createButton();

            remove.setDescription("Remove item");

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

            addComponent(add);

            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");

                addComponents(moveUp, moveDown);

                addStyledComponents(moveUp, moveDown);

            }

            setStyleName(ValoTheme.LAYOUT_COMPONENT_GROUP);

        }

        Button getEditOrCreateButton(){

            return editOrCreate;

        }

    }

    /**

     * @param e

     * @return

     */

    private void editOrCreate(F field) {

        if(editActionListener == null){

            throw new RuntimeException("editActionListener missing");

        }

        if(field.getValue() == null){

            // create

            editActionListener.onEntityEditorActionEvent(new EntityEditorActionEvent<V>(EditorActionType.ADD, null, field));

        } else {

            // edit

            V value = field.getValue();

            editActionListener.onEntityEditorActionEvent(new EntityEditorActionEvent<V>(EditorActionType.EDIT, (Class<V>) value.getClass(), value, field));

        }

    }

    private void updateComponentStates(){

        boolean isWritable = !getState().readOnly;

        int fieldsCount = getNestedFields().size();

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

            boolean isFirst = row == 0;

            boolean isLast = row == fieldsCount - 1;

            F field = (F) grid.getComponent(GRID_X_FIELD, row);

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

            boolean isWritableField = isWritableField(field);

            field.setReadOnly(!isWritableField);

            int addButtonIndex = 0;

            if(withEditButton){

                addButtonIndex++;

                // edit

                Button editCreateButton = ((Button)buttonGroup.getComponent(0));

                editCreateButton.setDescription(field.getValue() == null ? "New" : "Edit");

            }

            // add

            buttonGroup.getComponent(addButtonIndex).setEnabled(isWritable && (isLast || isOrderedCollection));

            // remove

            // can be always true, removing the last entry causes an new empty entry to be added.

            buttonGroup.getComponent(addButtonIndex + 1).setEnabled(isWritable);

            // up

            if(isOrderedCollection && buttonGroup.getComponentCount() >  addButtonIndex + 2){

                buttonGroup.getComponent(addButtonIndex + 2).setEnabled(isWritable && !isFirst);

                // down

                buttonGroup.getComponent(addButtonIndex + 3).setEnabled(isWritable && !isLast);

            }

        }

    }

    /**

     * @param isWritable

     * @param field

     * @return

     */

    public boolean isWritableField(F field) {

        boolean isWritable = !getState().readOnly;

        return isWritable && (field.getValue() == null

                || field.getValue() != null && testEditButtonPermission(field.getValue()));

    }

    /**

     * @param field

     * @return

     */

    protected boolean testEditButtonPermission(Object rowValue) {

        if(editPermissionTester != null) {

            return editPermissionTester.userHasEditPermission(rowValue);

        } else {

            return true;

        }

    }

    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 {

                logger.trace(String.format("field " + f.hashCode() + " at %d,%d", GRID_X_FIELD, r) + ", value: " + f.getValue());

                nestedFields.add(f);

            }

        }

        return Collections.unmodifiableList(nestedFields);

    }

    /**

     *

     * @param val

     * @return

     * @throws InstantiationException

     * @throws IllegalAccessException

     */

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

        F field;

        if(entityFieldInstantiator != null){

            field = entityFieldInstantiator.createNewInstance();

        } else {

            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;

    }

    /**

     * Adds the validator to the list of validators which

     * are applied to new fields and adds the validator to

     * existing fields

     *

     * @param validator

     */

    public void addFieldValidator(Validator validator){

        fieldValidators.add(validator);

        for(F field : fields()) {

            field.addValidator(validator);

        }

    }

    /**

     * removes the validator from the list of validators which

     * are applied to new fields and removes the validator from

     * existing fields

     *

     * @param validator

     */

    public void removeFieldValidator(Validator validator){

        fieldValidators.remove(validator);

        for(F field : fields()) {

            field.removeValidator(validator);

        }

    }

    /**

     * @return a unmodifialble List of the fieldValidators

     */

    public List<Validator> getFieldValidators() {

        return Collections.unmodifiableList(fieldValidators);

    }

    /**

     * 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 Optional<FieldGroup> getFieldGroup() {

        return Optional.empty();

    }

    /**

     * 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();

        Set<F> emptyFields = new HashSet<>();

        for(F f : nestedFields){

            f.commit();

            if(f.getValue() == null){

                emptyFields.add(f);

            }

        }

        for(F deleteF : emptyFields){

            removeRow(deleteF);

        }

        /*

        List<V> list = (List<V>) getPropertyDataSource().getValue();

        Person p = Person.NewInstance();

        p.setTitleCache("Hacky", true);

        list.add((V) p);

        List<V> clonedList = new ArrayList<>(list);

        list.clear();

        for(V value : clonedList){

            if(value != null){

                list.add(value);

            }

        }

        //

         */

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

        super.commit();

//        if(getValue().isEmpty() && valueInitiallyWasNull){

//            setPropertyDataSource(null);

//        }

    }

    /**

     * {@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

    }

    /**

     * with a button edit existing and to add new entities

     */

    public void withEditButton(boolean withEditButton){

        this.withEditButton = withEditButton;

        if(getPropertyDataSource() != null) {

            throw new RuntimeException("withEditButton must not be changed after the datasource is set.");

        }

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public boolean hasNullContent() {

        for(Field f : getNestedFields()){

            if(f instanceof CompositeCustomField){

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

                    return false;

                }

            }

        }

        return true;

    }

    /**

     * @return the enityFieldInstantiator

     */

    public EntityFieldInstantiator<F> getEntityFieldInstantiator() {

        return entityFieldInstantiator;

    }

    /**

     * @param enityFieldInstantiator the enityFieldInstantiator to set

     */

    public void setEntityFieldInstantiator(EntityFieldInstantiator<F> entityFieldInstantiator) {

        this.entityFieldInstantiator = entityFieldInstantiator;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public void setReadOnly(boolean readOnly) {

        super.setReadOnly(readOnly);

        updateComponentStates();

    }

    /**

     * @return the editPermissionTester

     */

    public EditPermissionTester getEditPermissionTester() {

        return editPermissionTester;

    }

    /**

     * @param editPermissionTester the editPermissionTester to set

     */

    public void setEditPermissionTester(EditPermissionTester editPermissionTester) {

        this.editPermissionTester = editPermissionTester;

    }

    /**

     * @return the editActionListener

     */

    public EntityEditorActionListener getEditActionListener() {

        return editActionListener;

    }

    /**

     * @param editActionListener the editActionListener to set

     */

    public void setEditActionListener(EntityEditorActionListener editActionListener) {

        this.editActionListener = editActionListener;

    }

}