/*
 * Copyright (c) 2004, PostgreSQL Global Development Group
 * See the LICENSE file in the project root for more information.
 */

package org.postgresql.util;

import java.io.Serializable;
import java.sql.SQLException;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.util.Calendar;
import java.util.Date;
import java.util.StringTokenizer;

This implements a class that handles the PostgreSQL interval type.
/**
 * This implements a class that handles the PostgreSQL interval type.
 */
public class PGInterval extends PGobject implements Serializable, Cloneable {

  private int years;
  private int months;
  private int days;
  private int hours;
  private int minutes;
  private double seconds;

  private static final DecimalFormat secondsFormat;

  static {
    secondsFormat = new DecimalFormat("0.00####");
    DecimalFormatSymbols dfs = secondsFormat.getDecimalFormatSymbols();
    dfs.setDecimalSeparator('.');
    secondsFormat.setDecimalFormatSymbols(dfs);
  }

  
required by the driver.
/**
   * required by the driver.
   */
  public PGInterval() {
    setType("interval");
  }

  
Initialize a interval with a given interval string representation.
Params:
value – String representated interval (e.g. '3 years 2 mons')
Throws:
SQLException – Is thrown if the string representation has an unknown format
See Also:
setValue(String)/**
   * Initialize a interval with a given interval string representation.
   *
   * @param value String representated interval (e.g. '3 years 2 mons')
   * @throws SQLException Is thrown if the string representation has an unknown format
   * @see #setValue(String)
   */
  public PGInterval(String value) throws SQLException {
    this();
    setValue(value);
  }

  
Initializes all values of this interval to the specified values.
Params:
years – years
months – months
days – days
hours – hours
minutes – minutes
seconds – seconds
See Also:
setValue(int, int, int, int, int, double)/**
   * Initializes all values of this interval to the specified values.
   *
   * @param years years
   * @param months months
   * @param days days
   * @param hours hours
   * @param minutes minutes
   * @param seconds seconds
   * @see #setValue(int, int, int, int, int, double)
   */
  public PGInterval(int years, int months, int days, int hours, int minutes, double seconds) {
    this();
    setValue(years, months, days, hours, minutes, seconds);
  }

  
Sets a interval string represented value to this instance. This method only recognize the
format, that Postgres returns - not all input formats are supported (e.g. '1 yr 2 m 3 s').
Params:
value – String representated interval (e.g. '3 years 2 mons')
Throws:
SQLException – Is thrown if the string representation has an unknown format/**
   * Sets a interval string represented value to this instance. This method only recognize the
   * format, that Postgres returns - not all input formats are supported (e.g. '1 yr 2 m 3 s').
   *
   * @param value String representated interval (e.g. '3 years 2 mons')
   * @throws SQLException Is thrown if the string representation has an unknown format
   */
  public void setValue(String value) throws SQLException {
    final boolean ISOFormat = !value.startsWith("@");

    // Just a simple '0'
    if (!ISOFormat && value.length() == 3 && value.charAt(2) == '0') {
      setValue(0, 0, 0, 0, 0, 0.0);
      return;
    }

    int years = 0;
    int months = 0;
    int days = 0;
    int hours = 0;
    int minutes = 0;
    double seconds = 0;

    try {
      String valueToken = null;

      value = value.replace('+', ' ').replace('@', ' ');
      final StringTokenizer st = new StringTokenizer(value);
      for (int i = 1; st.hasMoreTokens(); i++) {
        String token = st.nextToken();

        if ((i & 1) == 1) {
          int endHours = token.indexOf(':');
          if (endHours == -1) {
            valueToken = token;
            continue;
          }

          // This handles hours, minutes, seconds and microseconds for
          // ISO intervals
          int offset = (token.charAt(0) == '-') ? 1 : 0;

          hours = nullSafeIntGet(token.substring(offset + 0, endHours));
          minutes = nullSafeIntGet(token.substring(endHours + 1, endHours + 3));

          // Pre 7.4 servers do not put second information into the results
          // unless it is non-zero.
          int endMinutes = token.indexOf(':', endHours + 1);
          if (endMinutes != -1) {
            seconds = nullSafeDoubleGet(token.substring(endMinutes + 1));
          }

          if (offset == 1) {
            hours = -hours;
            minutes = -minutes;
            seconds = -seconds;
          }

          valueToken = null;
        } else {
          // This handles years, months, days for both, ISO and
          // Non-ISO intervals. Hours, minutes, seconds and microseconds
          // are handled for Non-ISO intervals here.

          if (token.startsWith("year")) {
            years = nullSafeIntGet(valueToken);
          } else if (token.startsWith("mon")) {
            months = nullSafeIntGet(valueToken);
          } else if (token.startsWith("day")) {
            days = nullSafeIntGet(valueToken);
          } else if (token.startsWith("hour")) {
            hours = nullSafeIntGet(valueToken);
          } else if (token.startsWith("min")) {
            minutes = nullSafeIntGet(valueToken);
          } else if (token.startsWith("sec")) {
            seconds = nullSafeDoubleGet(valueToken);
          }
        }
      }
    } catch (NumberFormatException e) {
      throw new PSQLException(GT.tr("Conversion of interval failed"),
          PSQLState.NUMERIC_CONSTANT_OUT_OF_RANGE, e);
    }

    if (!ISOFormat && value.endsWith("ago")) {
      // Inverse the leading sign
      setValue(-years, -months, -days, -hours, -minutes, -seconds);
    } else {
      setValue(years, months, days, hours, minutes, seconds);
    }
  }

  
Set all values of this interval to the specified values.
Params:
years – years
months – months
days – days
hours – hours
minutes – minutes
seconds – seconds/**
   * Set all values of this interval to the specified values.
   *
   * @param years years
   * @param months months
   * @param days days
   * @param hours hours
   * @param minutes minutes
   * @param seconds seconds
   */
  public void setValue(int years, int months, int days, int hours, int minutes, double seconds) {
    setYears(years);
    setMonths(months);
    setDays(days);
    setHours(hours);
    setMinutes(minutes);
    setSeconds(seconds);
  }

  
Returns the stored interval information as a string.
Returns:
String represented interval/**
   * Returns the stored interval information as a string.
   *
   * @return String represented interval
   */
  public String getValue() {
    return years + " years "
        + months + " mons "
        + days + " days "
        + hours + " hours "
        + minutes + " mins "
        + secondsFormat.format(seconds) + " secs";
  }

  
Returns the years represented by this interval.
Returns:
years represented by this interval/**
   * Returns the years represented by this interval.
   *
   * @return years represented by this interval
   */
  public int getYears() {
    return years;
  }

  
Set the years of this interval to the specified value.
Params:
years – years to set/**
   * Set the years of this interval to the specified value.
   *
   * @param years years to set
   */
  public void setYears(int years) {
    this.years = years;
  }

  
Returns the months represented by this interval.
Returns:
months represented by this interval/**
   * Returns the months represented by this interval.
   *
   * @return months represented by this interval
   */
  public int getMonths() {
    return months;
  }

  
Set the months of this interval to the specified value.
Params:
months – months to set/**
   * Set the months of this interval to the specified value.
   *
   * @param months months to set
   */
  public void setMonths(int months) {
    this.months = months;
  }

  
Returns the days represented by this interval.
Returns:
days represented by this interval/**
   * Returns the days represented by this interval.
   *
   * @return days represented by this interval
   */
  public int getDays() {
    return days;
  }

  
Set the days of this interval to the specified value.
Params:
days – days to set/**
   * Set the days of this interval to the specified value.
   *
   * @param days days to set
   */
  public void setDays(int days) {
    this.days = days;
  }

  
Returns the hours represented by this interval.
Returns:
hours represented by this interval/**
   * Returns the hours represented by this interval.
   *
   * @return hours represented by this interval
   */
  public int getHours() {
    return hours;
  }

  
Set the hours of this interval to the specified value.
Params:
hours – hours to set/**
   * Set the hours of this interval to the specified value.
   *
   * @param hours hours to set
   */
  public void setHours(int hours) {
    this.hours = hours;
  }

  
Returns the minutes represented by this interval.
Returns:
minutes represented by this interval/**
   * Returns the minutes represented by this interval.
   *
   * @return minutes represented by this interval
   */
  public int getMinutes() {
    return minutes;
  }

  
Set the minutes of this interval to the specified value.
Params:
minutes – minutes to set/**
   * Set the minutes of this interval to the specified value.
   *
   * @param minutes minutes to set
   */
  public void setMinutes(int minutes) {
    this.minutes = minutes;
  }

  
Returns the seconds represented by this interval.
Returns:
seconds represented by this interval/**
   * Returns the seconds represented by this interval.
   *
   * @return seconds represented by this interval
   */
  public double getSeconds() {
    return seconds;
  }

  
Set the seconds of this interval to the specified value.
Params:
seconds – seconds to set/**
   * Set the seconds of this interval to the specified value.
   *
   * @param seconds seconds to set
   */
  public void setSeconds(double seconds) {
    this.seconds = seconds;
  }

  
Rolls this interval on a given calendar.
Params:
cal – Calendar instance to add to/**
   * Rolls this interval on a given calendar.
   *
   * @param cal Calendar instance to add to
   */
  public void add(Calendar cal) {
    // Avoid precision loss
    // Be aware postgres doesn't return more than 60 seconds - no overflow can happen
    final int microseconds = (int) (getSeconds() * 1000000.0);
    final int milliseconds = (microseconds + ((microseconds < 0) ? -500 : 500)) / 1000;

    cal.add(Calendar.MILLISECOND, milliseconds);
    cal.add(Calendar.MINUTE, getMinutes());
    cal.add(Calendar.HOUR, getHours());
    cal.add(Calendar.DAY_OF_MONTH, getDays());
    cal.add(Calendar.MONTH, getMonths());
    cal.add(Calendar.YEAR, getYears());
  }

  
Rolls this interval on a given date.
Params:
date – Date instance to add to/**
   * Rolls this interval on a given date.
   *
   * @param date Date instance to add to
   */
  public void add(Date date) {
    final Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    add(cal);
    date.setTime(cal.getTime().getTime());
  }

  
Add this interval's value to the passed interval. This is backwards to what I would expect, but
this makes it match the other existing add methods.
Params:
interval – intval to add/**
   * Add this interval's value to the passed interval. This is backwards to what I would expect, but
   * this makes it match the other existing add methods.
   *
   * @param interval intval to add
   */
  public void add(PGInterval interval) {
    interval.setYears(interval.getYears() + getYears());
    interval.setMonths(interval.getMonths() + getMonths());
    interval.setDays(interval.getDays() + getDays());
    interval.setHours(interval.getHours() + getHours());
    interval.setMinutes(interval.getMinutes() + getMinutes());
    interval.setSeconds(interval.getSeconds() + getSeconds());
  }

  
Scale this interval by an integer factor. The server can scale by arbitrary factors, but that
would require adjusting the call signatures for all the existing methods like getDays() or
providing our own justification of fractional intervals. Neither of these seem like a good idea
without a strong use case.
Params:
factor – scale factor/**
   * Scale this interval by an integer factor. The server can scale by arbitrary factors, but that
   * would require adjusting the call signatures for all the existing methods like getDays() or
   * providing our own justification of fractional intervals. Neither of these seem like a good idea
   * without a strong use case.
   *
   * @param factor scale factor
   */
  public void scale(int factor) {
    setYears(factor * getYears());
    setMonths(factor * getMonths());
    setDays(factor * getDays());
    setHours(factor * getHours());
    setMinutes(factor * getMinutes());
    setSeconds(factor * getSeconds());
  }

  
Returns integer value of value or 0 if value is null.
Params:
value – integer as string value
Throws:
NumberFormatException – if the string contains invalid chars
Returns:
integer parsed from string value/**
   * Returns integer value of value or 0 if value is null.
   *
   * @param value integer as string value
   * @return integer parsed from string value
   * @throws NumberFormatException if the string contains invalid chars
   */
  private static int nullSafeIntGet(String value) throws NumberFormatException {
    return (value == null) ? 0 : Integer.parseInt(value);
  }

  
Returns double value of value or 0 if value is null.
Params:
value – double as string value
Throws:
NumberFormatException – if the string contains invalid chars
Returns:
double parsed from string value/**
   * Returns double value of value or 0 if value is null.
   *
   * @param value double as string value
   * @return double parsed from string value
   * @throws NumberFormatException if the string contains invalid chars
   */
  private static double nullSafeDoubleGet(String value) throws NumberFormatException {
    return (value == null) ? 0 : Double.parseDouble(value);
  }

  
Returns whether an object is equal to this one or not.
Params:
obj – Object to compare with
Returns:
true if the two intervals are identical/**
   * Returns whether an object is equal to this one or not.
   *
   * @param obj Object to compare with
   * @return true if the two intervals are identical
   */
  public boolean equals(Object obj) {
    if (obj == null) {
      return false;
    }

    if (obj == this) {
      return true;
    }

    if (!(obj instanceof PGInterval)) {
      return false;
    }

    final PGInterval pgi = (PGInterval) obj;

    return pgi.years == years
        && pgi.months == months
        && pgi.days == days
        && pgi.hours == hours
        && pgi.minutes == minutes
        && Double.doubleToLongBits(pgi.seconds) == Double.doubleToLongBits(seconds);
  }

  
Returns a hashCode for this object.
Returns:
hashCode/**
   * Returns a hashCode for this object.
   *
   * @return hashCode
   */
  public int hashCode() {
    return ((((((7 * 31 + (int) Double.doubleToLongBits(seconds)) * 31 + minutes) * 31 + hours) * 31
        + days) * 31 + months) * 31 + years) * 31;
  }

  @Override
  public Object clone() throws CloneNotSupportedException {
    // squid:S2157 "Cloneables" should implement "clone
    return super.clone();
  }
}