package org.activityinfo.ui.client.component.filter;

/*
 * #%L
 * ActivityInfo Server
 * %%
 * Copyright (C) 2009 - 2013 UNICEF
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public 
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-3.0.html>.
 * #L%
 */

import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
import com.google.gwt.event.shared.GwtEvent;
import com.google.gwt.event.shared.HandlerManager;
import com.google.gwt.event.shared.HandlerRegistration;
import org.activityinfo.legacy.shared.Log;
import org.activityinfo.legacy.shared.command.Filter;
import org.activityinfo.ui.client.page.entry.ActivityFilterPanel;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class FilterPanelSet implements FilterPanel {

    private List<FilterPanel> panels;
    private HandlerManager manager;
    private List<HandlerRegistration> myRegistrations;

    public FilterPanelSet(FilterPanel... panels) {
        super();
        this.panels = Arrays.asList(panels);
    }

    private HandlerManager ensureHandlers() {
        if (manager == null) {
            manager = new HandlerManager(this);
            myRegistrations = new ArrayList<HandlerRegistration>();
            for (FilterPanel panel : panels) {
                HandlerRegistration registration = panel.addValueChangeHandler(new ValueChangeHandler<Filter>() {
                    @Override
                    public void onValueChange(ValueChangeEvent<Filter> event) {
                        // reset attribute- and partner filters when a different activity, database (data entry)
                        // or indicator (reports) is selected
                        if (event.getSource() instanceof ActivityFilterPanel ||
                            event.getSource() instanceof IndicatorFilterPanel) {
                            clearAttributeAndPartnerFilters();
                        }

                        Filter value = composeFilter(new Filter(), null);
                        Log.debug("FilterPanelSet: Filter changed = " + value);
                        ValueChangeEvent.fire(FilterPanelSet.this, value);
                    }
                });
                myRegistrations.add(registration);
            }
        }
        return manager;
    }

    private void clearAttributeAndPartnerFilters() {
        for (FilterPanel panel : panels) {
            if (panel instanceof AttributeFilterPanel) {
                ((AttributeFilterPanel) panel).clearFilter();
            } else if (panel instanceof AttributeGroupFilterWidgets) {
                ((AttributeGroupFilterWidgets) panel).clearFilter();
            } else if (panel instanceof PartnerFilterPanel) {
                ((PartnerFilterPanel) panel).clearFilter();
            }
        }
    }

    @Override
    public Filter getValue() {
        return composeFilter(new Filter(), null);
    }

    @Override
    public void applyBaseFilter(Filter baseFilter) {
        for (FilterPanel panel : panels) {
            panel.applyBaseFilter(composeFilter(baseFilter, panel));
        }
    }

    private Filter composeFilter(Filter baseFilter, FilterPanel exclude) {
        Filter filter = baseFilter;
        for (FilterPanel panel : panels) {
            if (panel != exclude) {
                filter = new Filter(filter, panel.getValue());
            }
        }
        return filter;
    }

    @Override
    public void setValue(Filter value) {
        for (FilterPanel panel : panels) {
            panel.applyBaseFilter(value);
            panel.setValue(value);
        }
    }

    @Override
    public void setValue(Filter value, boolean fireEvents) {
        for (FilterPanel panel : panels) {
            panel.applyBaseFilter(value);
            panel.setValue(value, fireEvents);
        }
    }

    @Override
    public HandlerRegistration addValueChangeHandler(ValueChangeHandler<Filter> handler) {
        final HandlerRegistration reg = ensureHandlers().addHandler(ValueChangeEvent.getType(), handler);
        return new HandlerRegistration() {
            @Override
            public void removeHandler() {
                reg.removeHandler();
                if (manager.getHandlerCount(ValueChangeEvent.getType()) == 0) {
                    for (HandlerRegistration myReg : myRegistrations) {
                        myReg.removeHandler();
                    }
                }
                manager = null;
            }
        };
    }

    @Override
    public void fireEvent(GwtEvent<?> event) {
        if (manager != null) {
            manager.fireEvent(event);
        }
    }
}