/* Copyright (C) 2011, 2012, 2013 by Bundesanstalt für Gewässerkunde
 * Software engineering by Intevation GmbH
 *
 * This file is Free Software under the GNU AGPL (>=v3)
 * and comes with ABSOLUTELY NO WARRANTY! Check out the
 * documentation coming with Dive4Elements River for details.
 */

package org.dive4elements.river.model;

import java.io.Serializable;
import java.math.BigDecimal;
import java.util.List;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

import org.apache.log4j.Logger;
import org.dive4elements.river.backend.SessionHolder;
import org.hibernate.Query;
import org.hibernate.Session;

/** Database-mapped Gauge with all info about it. */
@Entity
@Table(name = "gauges")
public class Gauge implements Serializable, Comparable<Gauge> {
    private static final Logger log = Logger.getLogger(Gauge.class);

    public static final int MASTER_DISCHARGE_TABLE = 0;

    private Integer id;
    private String name;
    private River river;
    private BigDecimal station;
    private BigDecimal aeo;
    private BigDecimal datum;
    private Long officialNumber;
    private Range range;

    private List<DischargeTable> dischargeTables;

    /** MainValues at this Gauge. */
    protected List<MainValue> mainValues;

    public Gauge() {
    }

    public Gauge(final String name, final River river, final BigDecimal station, final BigDecimal aeo, final BigDecimal datum, final Long officialNumber,
            final Range range) {
        this.name = name;
        this.river = river;
        this.station = station;
        this.aeo = aeo;
        this.datum = datum;
        this.officialNumber = officialNumber;
        this.range = range;
    }

    @Id
    @SequenceGenerator(name = "SEQUENCE_GAUGES_ID_SEQ", sequenceName = "GAUGES_ID_SEQ", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SEQUENCE_GAUGES_ID_SEQ")
    @Column(name = "id")
    public Integer getId() {
        return this.id;
    }

    public void setId(final Integer id) {
        this.id = id;
    }

    @OneToOne
    @JoinColumn(name = "river_id")
    public River getRiver() {
        return this.river;
    }

    public void setRiver(final River river) {
        this.river = river;
    }

    @Column(name = "name")
    public String getName() {
        return this.name;
    }

    public void setName(final String name) {
        this.name = name;
    }

    @Column(name = "station") // FIXME: type mapping needed
    public BigDecimal getStation() {
        return this.station;
    }

    public void setStation(final BigDecimal station) {
        this.station = station;
    }

    @Column(name = "aeo") // FIXME: type mapping needed
    public BigDecimal getAeo() {
        return this.aeo;
    }

    public void setAeo(final BigDecimal aeo) {
        this.aeo = aeo;
    }

    @Column(name = "datum") // FIXME: type mapping needed
    public BigDecimal getDatum() {
        return this.datum;
    }

    public void setDatum(final BigDecimal datum) {
        this.datum = datum;
    }

    @Column(name = "official_number")
    public Long getOfficialNumber() {
        return this.officialNumber;
    }

    public void setOfficialNumber(final Long officialNumber) {
        this.officialNumber = officialNumber;
    }

    @OneToOne
    @JoinColumn(name = "range_id")
    public Range getRange() {
        return this.range;
    }

    public void setRange(final Range range) {
        this.range = range;
    }

    @OneToMany
    @JoinColumn(name = "gauge_id")
    public List<DischargeTable> getDischargeTables() {
        return this.dischargeTables;
    }

    public void setDischargeTables(final List<DischargeTable> dischargeTables) {
        this.dischargeTables = dischargeTables;
    }

    /**
     * Returns min and max W values of this gauge.
     *
     * @return the min and max W value of this gauge [min,max].
     */
    public double[] determineMinMaxW() {
        final Session session = SessionHolder.HOLDER.get();

        final DischargeTable dischargeTable = fetchMasterDischargeTable();

        if (dischargeTable == null) {
            return null;
        }

        final Query query = session.createQuery("select min(w) as min, max(w) as max from DischargeTableValue " + "where table_id =:table");
        query.setParameter("table", dischargeTable.getId());

        final List<?> results = query.list();
        if (results.isEmpty()) {
            log.error("No values in discharge table found.");
            return null;
        }

        final Object[] result = (Object[]) results.get(0);

        final BigDecimal a = (BigDecimal) result[0];
        final BigDecimal b = (BigDecimal) result[1];

        return a != null && b != null ? new double[] { a.doubleValue(), b.doubleValue() } : null;
    }

    @OneToMany
    @JoinColumn(name = "gauge_id")
    public List<MainValue> getMainValues() {
        return this.mainValues;
    }

    public void setMainValues(final List<MainValue> mainValues) {
        this.mainValues = mainValues;
    }

    public static Gauge getGaugeByOfficialNumber(final long number) {
        final Session session = SessionHolder.HOLDER.get();

        final Query query = session.createQuery("from Gauge where officialNumber=:number");

        query.setParameter("number", number);

        final List<Gauge> results = query.list();

        return results.isEmpty() ? null : results.get(0);
    }

    public static Gauge getGaugeByOfficialNumber(final long number, final String river_name) {
        final Session session = SessionHolder.HOLDER.get();

        final Query query = session.createQuery("from Gauge as gau " + "where gau.officialNumber=:number and gau.river.name=:river_name");

        query.setParameter("number", number);
        query.setParameter("river_name", river_name);

        final List<Gauge> results = query.list();

        return results.isEmpty() ? null : results.get(0);
    }

    public static Gauge getGaugeByNameAndRiver(final String gauge_name, final River river) {
        final Session session = SessionHolder.HOLDER.get();

        final Query query = session.createQuery("from Gauge as gau " + "where gau.name=:name and gau.river=:river");

        query.setParameter("name", gauge_name);
        query.setParameter("river", river);

        final List<Gauge> results = query.list();

        return results.isEmpty() ? null : results.get(0);
    }

    public DischargeTable fetchMasterDischargeTable() {
        final Session session = SessionHolder.HOLDER.get();

        final Query query = session.createQuery("from DischargeTable " + "where kind = 0 " + "and gauge = :gauge");

        query.setParameter("gauge", this);

        final List<Object> results = query.list();

        return results.isEmpty() ? null : (DischargeTable) results.get(0);
    }

    /**
     * Fetches from the database the most recent discharge table
     */
    public DischargeTable fetchRecentDischargeTable() {
        final Session session = SessionHolder.HOLDER.get();

        final Query query = session.createQuery("FROM DischargeTable" //
                + " WHERE (gauge = :gauge)" //
                + " ORDER BY timeInterval.startTime DESC");

        query.setParameter("gauge", this);

        final List<Object> results = query.list();

        return results.isEmpty() ? null : (DischargeTable) results.get(0);
    }

    /**
     * Returns an array of [days, qs] necessary to create duration curves.
     *
     * @return a 2dim array of [days, qs] where days is an int[] and qs is
     *         an double[].
     */
    public Object[] fetchDurationCurveData() {
        final Session session = SessionHolder.HOLDER.get();

        final Query query = session.createQuery("select cast(nmv.name as integer) as days, mv.value as q " //
                + "from MainValue as mv " //
                + "join mv.mainValue as nmv " //
                + "join nmv.type mvt " //
                + "where mvt.name = 'D' and mv.gauge.id = :gauge_id " + "order by days");

        query.setParameter("gauge_id", getId());

        final List<Object> results = query.list();
        final int[] days = new int[results.size()];
        final double[] qs = new double[results.size()];

        int idx = 0;

        for (final Object obj : results) {
            final Object[] arr = (Object[]) obj;

            try {
                final int day = ((Integer) arr[0]).intValue();
                final double q = ((BigDecimal) arr[1]).doubleValue();

                days[idx] = day;
                qs[idx++] = q;
            }
            catch (final NumberFormatException nfe) {
            }
        }

        return new Object[] { days, qs };
    }

    /**
     * Calculates the maximum and minimum W and Q values
     *
     * @return the MaxMinWQ object representing the calculated values
     */
    public MinMaxWQ fetchMaxMinWQ() {
        final Session session = SessionHolder.HOLDER.get();

        final Query query = session.createQuery("select max(mv.value) as max, min(mv.value) as min " + "from MainValue as mv " + "join mv.mainValue as nmv "
                + "join nmv.type mvt " + "where mvt.name in ('W', 'Q') " + "and mv.gauge.id = :gauge_id " + "group by mvt.name order by mvt.name");

        query.setParameter("gauge_id", getId());

        final List<Object> results = query.list();
        if (results.isEmpty()) {
            // No values found
            return new MinMaxWQ();
        }

        Object[] arr = (Object[]) results.get(0);
        final BigDecimal maxw = (BigDecimal) arr[0];
        final BigDecimal minw = (BigDecimal) arr[1];
        BigDecimal maxq = null;
        BigDecimal minq = null;

        if (results.size() > 1) {
            arr = (Object[]) results.get(1);
            maxq = (BigDecimal) arr[0];
            minq = (BigDecimal) arr[1];
        }

        return new MinMaxWQ(minw, maxw, minq, maxq);
    }

    @Override
    public int compareTo(final Gauge o) {
        return getName().compareTo(o.getName());
    }
}
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