package de.intevation.flys.model;

import java.math.BigDecimal;

import java.io.Serializable;

import java.util.List;

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

import org.hibernate.Session;
import org.hibernate.Query;

import de.intevation.flys.backend.SessionHolder;


@Entity
@Table(name = "gauges")
public class Gauge
implements   Serializable
{
    public static final int DEFAULT_SCALE = 100;

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

    private List<DischargeTable> dischargeTables;

    public Gauge() {
    }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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


    /**
     * Returns min and max W values of this gauge based with a DEFAULT_SCALE.
     *
     * @return min and max W value of this gauge [min,max].
     */
    public double[] determineMinMaxW() {
        return determineMinMaxW(DEFAULT_SCALE);
    }


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

        List<DischargeTable> tables   = getDischargeTables();
        DischargeTable dischargeTable = null;

        for (DischargeTable tmp: tables) {
            if (tmp.getKind() == 0) {
                dischargeTable = tmp;
                break;
            }
        }

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

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

        List     results = query.list();
        Object[] result  = (Object[]) results.get(0);

        return result != null
            ? new double[] {
                ((BigDecimal) result[0]).doubleValue() * scale,
                ((BigDecimal) result[1]).doubleValue() * scale}
            : null;
    }
}
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