/**
 * The contents of this file are subject to the license and copyright
 * detailed in the LICENSE and NOTICE files at the root of the source
 * tree and available online at
 *
 * http://www.dspace.org/license/
 */
package org.dspace.statistics.content.filter;

import org.dspace.statistics.SolrLoggerServiceImpl;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Calendar;

/**
 * Encapsulate a range of dates for Solr query filtering.
 * 
 * @author Kevin Van de Velde (kevin at atmire dot com)
 */
public class StatisticsSolrDateFilter implements StatisticsFilter {
    private Date startDate;
    private Date endDate;
    private String startStr;
    private String endStr;
    private String typeStr;


    public StatisticsSolrDateFilter() {
    }

    /**
     *  Set the start date as a string expression.
     *     
     * @param startStr
     *     statistics start date as a string
     *
     * Must be paired with {@link #setEndStr(String)}.
     */
    public void setStartStr(String startStr) {
        this.startStr = startStr;
    }

    /**
     * Set the end date as a string expression.
     *     
     * @param endStr
     *     statistics end date as a string
     *
     * Must be paired with {@link #setStartStr(String)}.
     */
    public void setEndStr(String endStr) {
        this.endStr = endStr;
    }

    /**
     * Set the range granularity:  DAY, MONTH, or YEAR.
     *
     * @param typeStr
     *     which granularity (case insensitive string: "day" / "month" / "year")
     */
    public void setTypeStr(String typeStr) {
        this.typeStr = typeStr;
    }

    /**
     * Set the start date as a Date object.
     *     
     * @param startDate
     *     statistics start date object
     *
     * Must be paired with {@link #setEndDate(Date)}.
     */
    public void setStartDate(Date startDate) {
        this.startDate = (startDate == null ? null : new Date(startDate.getTime()));
    }

    /**
     * Set the end date as a Date object.
     *     
     * @param endDate
     *     statistics end date object
     *
     * Must be paired with {@link #setStartDate(Date)}.
     */
    public void setEndDate(Date endDate) {
        this.endDate = (endDate == null ? null : new Date(endDate.getTime()));
    }

    /**
     * Convert the date range to a filter expression.
     * @return Solr date filter expression
     */
    @Override
    public String toQuery() {
        if (startDate == null || endDate == null) {
            // We have got strings instead of dates so calculate our dates out
            // of these strings
            Calendar startCal = Calendar.getInstance();

            startCal.clear(Calendar.MILLISECOND);
            startCal.clear(Calendar.SECOND);
            startCal.clear(Calendar.MINUTE);
            startCal.set(Calendar.HOUR_OF_DAY, 0);

            int dateType = -1;
            if (typeStr.equalsIgnoreCase("day")) {
                dateType = Calendar.DATE;
            } else if (typeStr.equalsIgnoreCase("month")) {
                dateType = Calendar.MONTH;
                startCal.set(Calendar.DATE, 1);
            } else if (typeStr.equalsIgnoreCase("year")) {
                startCal.clear(Calendar.MONTH);
                startCal.set(Calendar.DATE, 1);
                dateType = Calendar.YEAR;
            } else
            {
                return "";
            }

            Calendar endCal = (Calendar) startCal.clone();

            if (startDate == null)
            {
                if (startStr.startsWith("+"))
                {
                    startStr = startStr.substring(startStr.indexOf('+') + 1);
                }

                startCal.add(dateType, Integer.parseInt(startStr));
                startDate = startCal.getTime();
            }

            if (endDate == null)
            {
                if (endStr.startsWith("+"))
                {
                    endStr = endStr.substring(endStr.indexOf('+') + 1);
                }

                endCal.add(dateType, Integer.parseInt(endStr));
                endDate = endCal.getTime();
            }
        }

        //Parse the dates
        SimpleDateFormat formatter = new SimpleDateFormat(SolrLoggerServiceImpl.DATE_FORMAT_8601);
        String startDateParsed = formatter.format(startDate);
        String endDateParsed = formatter.format(endDate);

        //Create our string
        return "time:[" + startDateParsed + " TO " + endDateParsed + "]";
    }
}