GroupNodeViewModel.java

package org.jabref.gui.groups;

import java.util.List;
import java.util.Locale;
import java.util.Objects;
import java.util.Optional;
import java.util.stream.Collectors;

import javafx.beans.binding.Bindings;
import javafx.beans.binding.BooleanBinding;
import javafx.beans.property.SimpleBooleanProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.collections.FXCollections;
import javafx.collections.ListChangeListener;
import javafx.collections.ObservableList;
import javafx.scene.input.Dragboard;
import javafx.scene.paint.Color;

import org.jabref.gui.DragAndDropDataFormats;
import org.jabref.gui.StateManager;
import org.jabref.gui.icon.IconTheme;
import org.jabref.gui.icon.InternalMaterialDesignIcon;
import org.jabref.gui.icon.JabRefIcon;
import org.jabref.gui.util.BackgroundTask;
import org.jabref.gui.util.BindingsHelper;
import org.jabref.gui.util.CustomLocalDragboard;
import org.jabref.gui.util.DroppingMouseLocation;
import org.jabref.gui.util.TaskExecutor;
import org.jabref.logic.groups.DefaultGroupsFactory;
import org.jabref.logic.layout.format.LatexToUnicodeFormatter;
import org.jabref.logic.util.DelayTaskThrottler;
import org.jabref.model.FieldChange;
import org.jabref.model.database.BibDatabaseContext;
import org.jabref.model.entry.BibEntry;
import org.jabref.model.groups.AbstractGroup;
import org.jabref.model.groups.AutomaticGroup;
import org.jabref.model.groups.GroupEntryChanger;
import org.jabref.model.groups.GroupTreeNode;
import org.jabref.model.strings.StringUtil;

import com.google.common.base.Enums;
import org.fxmisc.easybind.EasyBind;

public class GroupNodeViewModel {

    private final String displayName;
    private final boolean isRoot;
    private final ObservableList<GroupNodeViewModel> children;
    private final BibDatabaseContext databaseContext;
    private final StateManager stateManager;
    private final GroupTreeNode groupNode;
    private final SimpleIntegerProperty hits;
    private final SimpleBooleanProperty hasChildren;
    private final SimpleBooleanProperty expandedProperty = new SimpleBooleanProperty();
    private final BooleanBinding anySelectedEntriesMatched;
    private final BooleanBinding allSelectedEntriesMatched;
    private final TaskExecutor taskExecutor;
    private final CustomLocalDragboard localDragBoard;
    private final ObservableList<BibEntry> entriesList;
    private final DelayTaskThrottler throttler;

    public GroupNodeViewModel(BibDatabaseContext databaseContext, StateManager stateManager, TaskExecutor taskExecutor, GroupTreeNode groupNode, CustomLocalDragboard localDragBoard) {
        this.databaseContext = Objects.requireNonNull(databaseContext);
        this.taskExecutor = Objects.requireNonNull(taskExecutor);
        this.stateManager = Objects.requireNonNull(stateManager);
        this.groupNode = Objects.requireNonNull(groupNode);
        this.localDragBoard = Objects.requireNonNull(localDragBoard);

        displayName = new LatexToUnicodeFormatter().format(groupNode.getName());
        isRoot = groupNode.isRoot();
        if (groupNode.getGroup() instanceof AutomaticGroup) {
            AutomaticGroup automaticGroup = (AutomaticGroup) groupNode.getGroup();

            children = automaticGroup.createSubgroups(this.databaseContext.getDatabase().getEntries())
                                     .stream()
                                     .map(this::toViewModel)
                                     .sorted((group1, group2) -> group1.getDisplayName().compareToIgnoreCase(group2.getDisplayName()))
                                     .collect(Collectors.toCollection(FXCollections::observableArrayList));
        } else {
            children = BindingsHelper.mapBacked(groupNode.getChildren(), this::toViewModel);
        }
        hasChildren = new SimpleBooleanProperty();
        hasChildren.bind(Bindings.isNotEmpty(children));
        hits = new SimpleIntegerProperty(0);
        calculateNumberOfMatches();
        expandedProperty.set(groupNode.getGroup().isExpanded());
        expandedProperty.addListener((observable, oldValue, newValue) -> groupNode.getGroup().setExpanded(newValue));

        // Register listener
        // The wrapper created by the FXCollections will set a weak listener on the wrapped list. This weak listener gets garbage collected. Hence, we need to maintain a reference to this list.
        entriesList = databaseContext.getDatabase().getEntries();
        entriesList.addListener(this::onDatabaseChanged);
        throttler = new DelayTaskThrottler(1000);

        ObservableList<Boolean> selectedEntriesMatchStatus = EasyBind.map(stateManager.getSelectedEntries(), groupNode::matches);
        anySelectedEntriesMatched = BindingsHelper.any(selectedEntriesMatchStatus, matched -> matched);
        allSelectedEntriesMatched = BindingsHelper.all(selectedEntriesMatchStatus, matched -> matched);
    }

    public GroupNodeViewModel(BibDatabaseContext databaseContext, StateManager stateManager, TaskExecutor taskExecutor, AbstractGroup group, CustomLocalDragboard localDragboard) {
        this(databaseContext, stateManager, taskExecutor, new GroupTreeNode(group), localDragboard);
    }

    static GroupNodeViewModel getAllEntriesGroup(BibDatabaseContext newDatabase, StateManager stateManager, TaskExecutor taskExecutor, CustomLocalDragboard localDragBoard) {
        return new GroupNodeViewModel(newDatabase, stateManager, taskExecutor, DefaultGroupsFactory.getAllEntriesGroup(), localDragBoard);
    }

    private GroupNodeViewModel toViewModel(GroupTreeNode child) {
        return new GroupNodeViewModel(databaseContext, stateManager, taskExecutor, child, localDragBoard);
    }

    public List<FieldChange> addEntriesToGroup(List<BibEntry> entries) {
        // TODO: warn if assignment has undesired side effects (modifies a field != keywords)
        //if (!WarnAssignmentSideEffects.warnAssignmentSideEffects(group, groupSelector.frame))
        //{
        //    return; // user aborted operation
        //}

        var changes = groupNode.addEntriesToGroup(entries);

        // Update appearance of group
        anySelectedEntriesMatched.invalidate();
        allSelectedEntriesMatched.invalidate();

        return changes;
        // TODO: Store undo
        // if (!undo.isEmpty()) {
        // groupSelector.concludeAssignment(UndoableChangeEntriesOfGroup.getUndoableEdit(target, undo), target.getNode(), assignedEntries);
    }

    public SimpleBooleanProperty expandedProperty() {
        return expandedProperty;
    }

    public BooleanBinding anySelectedEntriesMatchedProperty() {
        return anySelectedEntriesMatched;
    }

    public BooleanBinding allSelectedEntriesMatchedProperty() {
        return allSelectedEntriesMatched;
    }

    public SimpleBooleanProperty hasChildrenProperty() {
        return hasChildren;
    }

    public String getDisplayName() {
        return displayName;
    }

    public boolean isRoot() {
        return isRoot;
    }

    public String getDescription() {
        return groupNode.getGroup().getDescription().orElse("");
    }

    public SimpleIntegerProperty getHits() {
        return hits;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if ((o == null) || (getClass() != o.getClass())) {
            return false;
        }

        GroupNodeViewModel that = (GroupNodeViewModel) o;

        return groupNode.equals(that.groupNode);
    }

    @Override
    public String toString() {
        return "GroupNodeViewModel{" +
                "displayName='" + displayName + '\'' +
                ", isRoot=" + isRoot +
                ", icon='" + getIcon() + '\'' +
                ", children=" + children +
                ", databaseContext=" + databaseContext +
                ", groupNode=" + groupNode +
                ", hits=" + hits +
                '}';
    }

    @Override
    public int hashCode() {
        return groupNode.hashCode();
    }

    public JabRefIcon getIcon() {
        Optional<String> iconName = groupNode.getGroup().getIconName();
        return iconName.flatMap(this::parseIcon)
                       .orElseGet(this::createDefaultIcon);
    }

    private JabRefIcon createDefaultIcon() {
        Color color = groupNode.getGroup().getColor().orElse(IconTheme.getDefaultGroupColor());
        return IconTheme.JabRefIcons.DEFAULT_GROUP_ICON_COLORED.withColor(color);
    }

    private Optional<JabRefIcon> parseIcon(String iconCode) {
        return Enums.getIfPresent(IconTheme.JabRefIcons.class, iconCode.toUpperCase(Locale.ENGLISH))
                    .toJavaUtil()
                    .map(icon -> new InternalMaterialDesignIcon(getColor(), icon));
    }

    public ObservableList<GroupNodeViewModel> getChildren() {
        return children;
    }

    public GroupTreeNode getGroupNode() {
        return groupNode;
    }

    /**
     * Gets invoked if an entry in the current database changes.
     */
    private void onDatabaseChanged(ListChangeListener.Change<? extends BibEntry> change) {
        throttler.schedule(this::calculateNumberOfMatches);
    }

    private void calculateNumberOfMatches() {
        // We calculate the new hit value
        // We could be more intelligent and try to figure out the new number of hits based on the entry change
        // for example, a previously matched entry gets removed -> hits = hits - 1
        BackgroundTask
                .wrap(() -> groupNode.calculateNumberOfMatches(databaseContext.getDatabase()))
                .onSuccess(hits::setValue)
                .executeWith(taskExecutor);
    }

    public GroupTreeNode addSubgroup(AbstractGroup subgroup) {
        return groupNode.addSubgroup(subgroup);
    }

    void toggleExpansion() {
        expandedProperty().set(!expandedProperty().get());
    }

    boolean isMatchedBy(String searchString) {
        return StringUtil.isBlank(searchString) || StringUtil.containsIgnoreCase(getDisplayName(), searchString);
    }

    public Color getColor() {
        return groupNode.getGroup().getColor().orElse(IconTheme.getDefaultGroupColor());
    }

    public String getPath() {
        return groupNode.getPath();
    }

    public Optional<GroupNodeViewModel> getChildByPath(String pathToSource) {
        return groupNode.getChildByPath(pathToSource).map(this::toViewModel);
    }

    /**
     * Decides if the content stored in the given {@link Dragboard} can be droped on the given target row.
     * Currently, the following sources are allowed:
     *  - another group (will be added as subgroup on drop)
     *  - entries if the group implements {@link GroupEntryChanger} (will be assigned to group on drop)
     */
    public boolean acceptableDrop(Dragboard dragboard) {
        // TODO: we should also check isNodeDescendant
        boolean canDropOtherGroup = dragboard.hasContent(DragAndDropDataFormats.GROUP);
        boolean canDropEntries = localDragBoard.hasBibEntries() && (groupNode.getGroup() instanceof GroupEntryChanger);
        return canDropOtherGroup || canDropEntries;
    }

    public void moveTo(GroupNodeViewModel target) {
        // TODO: Add undo and display message
        //MoveGroupChange undo = new MoveGroupChange(((GroupTreeNodeViewModel)source.getParent()).getNode(),
        //        source.getNode().getPositionInParent(), target.getNode(), target.getChildCount());

        getGroupNode().moveTo(target.getGroupNode());
        //panel.getUndoManager().addEdit(new UndoableMoveGroup(this.groupsRoot, moveChange));
        //panel.markBaseChanged();
        //frame.output(Localization.lang("Moved group \"%0\".", node.getNode().getGroup().getName()));
    }

    public void moveTo(GroupTreeNode target, int targetIndex) {
        getGroupNode().moveTo(target, targetIndex);
    }

    public Optional<GroupTreeNode> getParent() {
        return groupNode.getParent();
    }

    public void draggedOn(GroupNodeViewModel target, DroppingMouseLocation mouseLocation) {
        Optional<GroupTreeNode> targetParent = target.getParent();
        if (targetParent.isPresent()) {
            int targetIndex = target.getPositionInParent();

            // In case we want to move an item in the same parent
            // and the item is moved down, we need to adjust the target index
            if (targetParent.equals(getParent())) {
                int sourceIndex = this.getPositionInParent();
                if (sourceIndex < targetIndex) {
                    targetIndex--;
                }
            }

            // Different actions depending on where the user releases the drop in the target row
            // Bottom + top -> insert source row before / after this row
            // Center -> add as child
            switch (mouseLocation) {
            case BOTTOM:
                this.moveTo(targetParent.get(), targetIndex + 1);
                break;
            case CENTER:
                this.moveTo(target);
                break;
            case TOP:
                this.moveTo(targetParent.get(), targetIndex);
                break;
            }
        } else {
            // No parent = root -> just add
            this.moveTo(target);
        }
    }

    private int getPositionInParent() {
        return groupNode.getPositionInParent();
    }
}