package org.bouncycastle.asn1;

import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.SimpleTimeZone;

import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.Strings;

- * UTC time object. Internal facade of ASN1UTCTime. 

This datatype is valid only from 1950-01-01 00:00:00 UTC until 2049-12-31 23:59:59 UTC.


X.690
11: Restrictions on BER employed by both CER and DER
11.8 UTCTime 
11.8.1 The encoding shall terminate with "Z",
as described in the ITU-T X.680 | ISO/IEC 8824-1 clause on UTCTime.

11.8.2 The seconds element shall always be present.

11.8.3 Midnight (GMT) shall be represented in the form:

"YYMMDD000000Z"

where "YYMMDD" represents the day following the midnight in question.
/**
- * UTC time object.
 * Internal facade of {@link ASN1UTCTime}.
 * <p>
 * This datatype is valid only from 1950-01-01 00:00:00 UTC until 2049-12-31 23:59:59 UTC.
 * </p>
 * <hr>
 * <p><b>X.690</b></p>
 * <p><b>11: Restrictions on BER employed by both CER and DER</b></p>
 * <p><b>11.8 UTCTime </b></p>
 * <b>11.8.1</b> The encoding shall terminate with "Z",
 * as described in the ITU-T X.680 | ISO/IEC 8824-1 clause on UTCTime.
 * <p>
 * <b>11.8.2</b> The seconds element shall always be present.
 * <p>
 * <b>11.8.3</b> Midnight (GMT) shall be represented in the form:
 * <blockquote>
 * "YYMMDD000000Z"
 * </blockquote>
 * where "YYMMDD" represents the day following the midnight in question.
 */
public class ASN1UTCTime
    extends ASN1Primitive
{
    private byte[]      time;

    
Return an UTC Time from the passed in object.
Params:
obj – an ASN1UTCTime or an object that can be converted into one.
Throws:
IllegalArgumentException – if the object cannot be converted.
Returns:
an ASN1UTCTime instance, or null./**
     * Return an UTC Time from the passed in object.
     *
     * @param obj an ASN1UTCTime or an object that can be converted into one.
     * @exception IllegalArgumentException if the object cannot be converted.
     * @return an ASN1UTCTime instance, or null.
     */
    public static ASN1UTCTime getInstance(
        Object  obj)
    {
        if (obj == null || obj instanceof ASN1UTCTime)
        {
            return (ASN1UTCTime)obj;
        }

        if (obj instanceof byte[])
        {
            try
            {
                return (ASN1UTCTime)fromByteArray((byte[])obj);
            }
            catch (Exception e)
            {
                throw new IllegalArgumentException("encoding error in getInstance: " + e.toString());
            }
        }

        throw new IllegalArgumentException("illegal object in getInstance: " + obj.getClass().getName());
    }

    
Return an UTC Time from a tagged object.
Params:
obj – the tagged object holding the object we want
explicit – true if the object is meant to be explicitly
             tagged false otherwise.
Throws:
IllegalArgumentException – if the tagged object cannot
              be converted.
Returns:
an ASN1UTCTime instance, or null./**
     * Return an UTC Time from a tagged object.
     *
     * @param obj the tagged object holding the object we want
     * @param explicit true if the object is meant to be explicitly
     *              tagged false otherwise.
     * @exception IllegalArgumentException if the tagged object cannot
     *               be converted.
     * @return an ASN1UTCTime instance, or null.
     */
    public static ASN1UTCTime getInstance(
        ASN1TaggedObject obj,
        boolean          explicit)
    {
        ASN1Object o = obj.getObject();

        if (explicit || o instanceof ASN1UTCTime)
        {
            return getInstance(o);
        }
        else
        {
            return new ASN1UTCTime(((ASN1OctetString)o).getOctets());
        }
    }

    
The correct format for this is YYMMDDHHMMSSZ (it used to be that seconds were
never encoded. When you're creating one of these objects from scratch, that's
what you want to use, otherwise we'll try to deal with whatever gets read from
the input stream... (this is why the input format is different from the getTime()
method output).

Params:
time – the time string./**
     * The correct format for this is YYMMDDHHMMSSZ (it used to be that seconds were
     * never encoded. When you're creating one of these objects from scratch, that's
     * what you want to use, otherwise we'll try to deal with whatever gets read from
     * the input stream... (this is why the input format is different from the getTime()
     * method output).
     * <p>
     *
     * @param time the time string.
     */
    public ASN1UTCTime(
        String time)
    {
        this.time = Strings.toByteArray(time);
        try
        {
            this.getDate();
        }
        catch (ParseException e)
        {
            throw new IllegalArgumentException("invalid date string: " + e.getMessage());
        }
    }

    
Base constructor from a java.util.date object
Params:
time – the Date to build the time from./**
     * Base constructor from a java.util.date object
     * @param time the Date to build the time from.
     */
    public ASN1UTCTime(
        Date time)
    {
        SimpleDateFormat dateF = new SimpleDateFormat("yyMMddHHmmss'Z'", DateUtil.EN_Locale);

        dateF.setTimeZone(new SimpleTimeZone(0,"Z"));

        this.time = Strings.toByteArray(dateF.format(time));
    }

    
Base constructor from a java.util.date and Locale - you may need to use this if the default locale
doesn't use a Gregorian calender so that the GeneralizedTime produced is compatible with other ASN.1 implementations.
Params:
time – a date object representing the time of interest.
locale – an appropriate Locale for producing an ASN.1 UTCTime value./**
     * Base constructor from a java.util.date and Locale - you may need to use this if the default locale
     * doesn't use a Gregorian calender so that the GeneralizedTime produced is compatible with other ASN.1 implementations.
     *
     * @param time a date object representing the time of interest.
     * @param locale an appropriate Locale for producing an ASN.1 UTCTime value.
     */
    public ASN1UTCTime(
        Date time,
        Locale locale)
    {
        SimpleDateFormat dateF = new SimpleDateFormat("yyMMddHHmmss'Z'", locale);

        dateF.setTimeZone(new SimpleTimeZone(0,"Z"));

        this.time = Strings.toByteArray(dateF.format(time));
    }

    ASN1UTCTime(
        byte[] time)
    {
        this.time = time;
    }

    
Return the time as a date based on whatever a 2 digit year will return. For
standardised processing use getAdjustedDate().
Throws:
ParseException – if the date string cannot be parsed.
Returns:
the resulting date/**
     * Return the time as a date based on whatever a 2 digit year will return. For
     * standardised processing use getAdjustedDate().
     *
     * @return the resulting date
     * @exception ParseException if the date string cannot be parsed.
     */
    public Date getDate()
        throws ParseException
    {
        SimpleDateFormat dateF = new SimpleDateFormat("yyMMddHHmmssz");

        return DateUtil.epochAdjust(dateF.parse(getTime()));
    }

    
Return the time as an adjusted date
in the range of 1950 - 2049.
Throws:
ParseException – if the date string cannot be parsed.
Returns:
a date in the range of 1950 to 2049./**
     * Return the time as an adjusted date
     * in the range of 1950 - 2049.
     *
     * @return a date in the range of 1950 to 2049.
     * @exception ParseException if the date string cannot be parsed.
     */
    public Date getAdjustedDate()
        throws ParseException
    {
        SimpleDateFormat dateF = new SimpleDateFormat("yyyyMMddHHmmssz");

        dateF.setTimeZone(new SimpleTimeZone(0,"Z"));
        
        return DateUtil.epochAdjust(dateF.parse(getAdjustedTime()));
    }

    
Return the time - always in the form of
 YYMMDDhhmmssGMT(+hh:mm|-hh:mm).

Normally in a certificate we would expect "Z" rather than "GMT",
however adding the "GMT" means we can just use:
    dateF = new SimpleDateFormat("yyMMddHHmmssz");

To read in the time and get a date which is compatible with our local
time zone.

Note: In some cases, due to the local date processing, this
may lead to unexpected results. If you want to stick the normal
convention of 1950 to 2049 use the getAdjustedTime() method.
/**
     * Return the time - always in the form of
     *  YYMMDDhhmmssGMT(+hh:mm|-hh:mm).
     * <p>
     * Normally in a certificate we would expect "Z" rather than "GMT",
     * however adding the "GMT" means we can just use:
     * <pre>
     *     dateF = new SimpleDateFormat("yyMMddHHmmssz");
     * </pre>
     * To read in the time and get a date which is compatible with our local
     * time zone.
     * <p>
     * <b>Note:</b> In some cases, due to the local date processing, this
     * may lead to unexpected results. If you want to stick the normal
     * convention of 1950 to 2049 use the getAdjustedTime() method.
     */
    public String getTime()
    {
        String stime = Strings.fromByteArray(time);

        //
        // standardise the format.
        //
        if (stime.indexOf('-') < 0 && stime.indexOf('+') < 0)
        {
            if (stime.length() == 11)
            {
                return stime.substring(0, 10) + "00GMT+00:00";
            }
            else
            {
                return stime.substring(0, 12) + "GMT+00:00";
            }
        }
        else
        {
            int index = stime.indexOf('-');
            if (index < 0)
            {
                index = stime.indexOf('+');
            }
            String d = stime;

            if (index == stime.length() - 3)
            {
                d += "00";
            }

            if (index == 10)
            {
                return d.substring(0, 10) + "00GMT" + d.substring(10, 13) + ":" + d.substring(13, 15);
            }
            else
            {
                return d.substring(0, 12) + "GMT" + d.substring(12, 15) + ":" +  d.substring(15, 17);
            }
        }
    }

    
Return a time string as an adjusted date with a 4 digit year. This goes
in the range of 1950 - 2049.
/**
     * Return a time string as an adjusted date with a 4 digit year. This goes
     * in the range of 1950 - 2049.
     */
    public String getAdjustedTime()
    {
        String   d = this.getTime();

        if (d.charAt(0) < '5')
        {
            return "20" + d;
        }
        else
        {
            return "19" + d;
        }
    }

    boolean isConstructed()
    {
        return false;
    }

    int encodedLength()
    {
        int length = time.length;

        return 1 + StreamUtil.calculateBodyLength(length) + length;
    }

    void encode(
        ASN1OutputStream  out)
        throws IOException
    {
        out.write(BERTags.UTC_TIME);

        int length = time.length;

        out.writeLength(length);

        for (int i = 0; i != length; i++)
        {
            out.write((byte)time[i]);
        }
    }

    boolean asn1Equals(
        ASN1Primitive o)
    {
        if (!(o instanceof ASN1UTCTime))
        {
            return false;
        }

        return Arrays.areEqual(time, ((ASN1UTCTime)o).time);
    }

    public int hashCode()
    {
        return Arrays.hashCode(time);
    }

    public String toString()
    {
      return Strings.fromByteArray(time);
    }
}