package org.kuali.ole.krad;

import java.text.DateFormat;
import java.text.Format;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import org.apache.commons.lang3.StringUtils;
import org.apache.log4j.Logger;
import org.kuali.rice.krad.uif.UifConstants;
import org.kuali.rice.krad.uif.component.Component;
import org.kuali.rice.krad.uif.container.Group;
import org.kuali.rice.krad.uif.container.PageGroup;
import org.kuali.rice.krad.uif.util.ObjectPropertyUtils;
import org.kuali.rice.krad.web.form.UifFormBase;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;

/**
 * Utility class for supporting low-level KRAD optimizations.
 */
public final class OleComponentUtils {

        private static final Logger LOG = Logger.getLogger(OleComponentUtils.class);

        private static ThreadLocal<Format> CURRENCY_FORMAT = new ThreadLocal<Format>() {
                @Override
                protected Format initialValue() {
                        return NumberFormat.getCurrencyInstance();
                }
        };

        private static ThreadLocal<Format> DATE_FORMAT = new ThreadLocal<Format>() {
                @Override
                protected Format initialValue() {
                        return DateFormat.getDateInstance();
                }
        };

        /**
         * Gets the KRAD model for the active request.
         * 
         * @return KRAD model
         */
        public static Object getModel() {
                RequestAttributes attr = RequestContextHolder.getRequestAttributes();
                if (attr == null) {
                        return null;
                } else {
                        return attr.getAttribute(UifConstants.REQUEST_FORM,
                                        RequestAttributes.SCOPE_REQUEST);
                }
        }

        /**
         * Filters items for a group that also implements OleComponentUtils.
         */
        public static List<? extends Component> filterItems(
                        List<? extends Component> srcitems) {
                if (srcitems == null) {
                        return null;
                }

                Object model = getModel();
                if (model == null) {
                        return srcitems;
                } else {
                        LOG.debug("Filtering based on " + model);
                }

                List<Component> items = new ArrayList<Component>();
                filterloop: for (Component itemComponent : srcitems) {

                        // Filter out OleComponent instances matching true
                        if (itemComponent instanceof OleComponent) {
                                OleComponent oleComp = (OleComponent) itemComponent;
                                String filterProp = oleComp.getFilterModelProperty();
                                Object filterVal = filterProp == null ? null
                                                : ObjectPropertyUtils.getPropertyValue(model,
                                                                filterProp);
                                if (filterVal instanceof String)
                                        filterVal = Boolean.parseBoolean((String) filterVal);
                                if (filterVal == null && filterProp != null)
                                        filterVal = Boolean.TRUE;
                                if (Boolean.TRUE.equals(filterVal)) {
                                        LOG.debug("Omitting " + itemComponent.getClass() + " "
                                                        + itemComponent.getId() + ", " + filterProp
                                                        + " is true");
                                        continue filterloop;
                                } else {
                                        LOG.debug("Keeping " + itemComponent.getClass() + " "
                                                        + itemComponent.getId() + ", " + filterProp
                                                        + " is true");
                                }
                        }

                        items.add((Component) itemComponent.copy());
                }

                return items;
        }

        /**
         * Filters items for a view to remove non-current pages.
         */
        public static List<? extends Group> filterCurrentPage(String currentPageId,
                        List<? extends Group> srcitems) {
                if (srcitems == null) {
                        return null;
                }

                Object model = getModel();
                if (model == null || !(model instanceof UifFormBase))
                        return srcitems;

                if (StringUtils.isEmpty(currentPageId))
                        return srcitems;

                LOG.debug("Filtering view pages based on " + model + ", pageId = "
                                + currentPageId);

                List<Group> items = new ArrayList<Group>();
                for (Group group : srcitems) {
                        String compId = group.getId();

                        // Filter out OleComponent instances matching true
                        if ((group instanceof PageGroup) && !currentPageId.equals(compId)) {
                                LOG.debug("Omitting " + compId + ", not current page");
                                continue;
                        } else
                                LOG.debug("Keeping " + compId
                                                + ", current page or not a PageGroup");

                        items.add((Group) group.copy());
                }

                return items;
        }

        /**
         * Convenience method for converting {@link Number} to currency string
         * representation with minimal overhead.
         * 
         * <p>
         * Intended for use in KRAD SpEL expressions, for example:
         * </p>
         * 
         * <pre>
         * @{T(org.kuali.ole.krad.OleComponentUtils).formatAsCurrency(anAmount)}
         * </pre>
         * 
         * @param amount
         *            Currency amount
         * @return formatted currency string
         */
        public static String formatAsCurrency(Number amount) {
                return amount == null ? "" : CURRENCY_FORMAT.get().format(amount);
        }

        /**
         * Convenience method for converting {@link Date} to a string
         * representation with minimal overhead.
         * 
         * <p>
         * Intended for use in KRAD SpEL expressions, for example:
         * </p>
         * 
         * <pre>
         * @{T(org.kuali.ole.krad.OleComponentUtils).formatDate(aDate)}
         * </pre>
         * 
         * @param date date
         * @return formatted date string
         */
        public static String formatDate(Date date) {
                return date == null ? "" : DATE_FORMAT.get().format(date);
        }

        private OleComponentUtils() {
        }

}