content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you under the Apache License, Version 2.0 (the
   *  "License"); you may not use this file except in compliance
   *  with the License.  You may obtain a copy of the License at
   *
   *        http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing,
   *  software distributed under the License is distributed on an
   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   *  KIND, either express or implied.  See the License for the
   *  specific language governing permissions and limitations
   *  under the License.
   */
  package org.apache.causeway.commons.internal.base;
  
  import java.math.BigDecimal;
  import java.math.RoundingMode;
  import java.sql.Timestamp;
  import java.time.Instant;
  import java.time.LocalDate;
  import java.time.LocalDateTime;
  import java.time.LocalTime;
  import java.time.OffsetDateTime;
  import java.time.OffsetTime;
  import java.time.ZoneId;
  import java.time.ZoneOffset;
  import java.time.ZonedDateTime;
  import java.time.format.DateTimeFormatter;
  import java.time.format.DateTimeFormatterBuilder;
  import java.time.temporal.Temporal;
  import java.util.Locale;
  import java.util.Optional;
  import java.util.regex.Pattern;
  
  import org.jspecify.annotations.Nullable;
  
  import org.apache.causeway.commons.collections.Can;
  
  import org.jspecify.annotations.NonNull;
  import lombok.experimental.UtilityClass;
  
  /**
   * <h1>- internal use only -</h1>
   * <p>
   * Provides time related functions.
   * </p>
   * <p>
   * <b>WARNING</b>: Do <b>NOT</b> use any of the classes provided by this package! <br/>
   * These may be changed or removed without notice!
   * </p>
   *
   * @since 2.0
   */
  @UtilityClass
  public final class _Temporals {
  
      public final ZoneId UTC = ZoneId.of("UTC");
  
      /**
       * The default date/time format (seconds resolution): {@code 'yyyy-MM-dd HH:mm:ss'}.
       * As used for auditing, session-logging, etc.
       */
      public final DateTimeFormatter DEFAULT_LOCAL_DATETIME_FORMATTER =
              DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
  
      /**
       * The default date/time format (milliseconds resolution): {@code 'yyyy-MM-dd HH:mm:ss.SSS'}.
       * As used eg. for Xray.
       */
      public final DateTimeFormatter DEFAULT_LOCAL_DATETIME_FORMATTER_WITH_MILLIS =
              DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS");
  
      /**
       * Returns duration between {@code startedAt} and {@code completedAt} in <i>seconds</i>,
       * to 3 decimal places.
       * @implNote if {@code completedAt} is before {@code startedAt},
       * a negative value is returned.
       */
      public Optional<BigDecimal> secondsBetweenAsDecimal(
              final @Nullable Timestamp startedAt,
              final @Nullable Timestamp completedAt) {
          return startedAt!=null
                  && completedAt!=null
                          ? Optional.of(millisToSeconds(completedAt.getTime() - startedAt.getTime()))
                          : Optional.empty();
      }
  
      // -- ZONE TRANSLATION
  
      /**
       * Translates given {@link Temporal} into provided {@link ZoneId} preserving the time instant.
       * If timeZone is absent, acts as a identity operator.
       * @param temporal - the {@link Temporal} to translate (required)
       * @param zoneId - target {@link ZoneId} (required)
       */
      public ZonedDateTime translateToTimeZone(final @NonNull ZonedDateTime temporal, final @NonNull ZoneId zoneId) {
          return temporal.withZoneSameInstant(zoneId);
      }
  
      /**
       * Translates given {@link Temporal} into provided {@link ZoneId} preserving the time instant.
       * If timeZone is absent, acts as a identity operator.
       * @param temporal - the {@link Temporal} to translate (required)
       * @param zoneId - target {@link ZoneId} (required)
       */
      public ZonedDateTime translateToTimeZone(final @NonNull OffsetDateTime temporal, final @NonNull ZoneId zoneId) {
          return ZonedDateTime.ofInstant(temporal.toInstant(), zoneId);
      }
  
      /**
       * Translates given {@link Temporal} into provided {@link ZoneId} preserving the time instant.
       * If timeZone is absent, acts as a identity operator.
       * @param temporal - the {@link Temporal} to translate (required)
       * @param offset - target {@link ZoneOffset} (required)
       */
      public OffsetTime translateToTimeOffset(final @NonNull OffsetTime temporal, final @NonNull ZoneOffset offset) {
          return temporal.withOffsetSameInstant(offset);
      }
  
      // -- TIME ZONE RENDERING
  
      public final DateTimeFormatter ISO_OFFSET_ONLY_FORMAT = new DateTimeFormatterBuilder()
              .appendOffsetId()
              .toFormatter(Locale.US); // arbitrarily picking a locale, just in case; (should have no effect)
  
      public final DateTimeFormatter DEFAULT_ZONEID_ONLY_FORMAT = new DateTimeFormatterBuilder()
              .appendPattern("VV")
              .toFormatter(Locale.US); // arbitrarily picking a locale, just in case; (should have no effect)
  
      public String formatZoneId(final ZoneId zoneId, final DateTimeFormatter zoneOnlyFormatter) {
          return zoneOnlyFormatter.format(ZonedDateTime.ofInstant(Instant.EPOCH, zoneId));
      }
  
      public String formatZoneId(final ZoneId zoneId) {
          return formatZoneId(zoneId, DEFAULT_ZONEID_ONLY_FORMAT);
      }
  
      // -- TEMPORAL TO STRING CONVERTERS
  
      private static final String FRACTIONAL_SECONDS_READ_PATTERN =
              "[.SSSSSSSSS][.SSSSSS][.SSS][.S]";
  
      private static final DateTimeFormatter OFFSETTIME_DATASTORE_FORMATTER =
              DateTimeFormatter.ofPattern("HH:mm:ss.SSSSSSSSS XXX");
  
      private static final DateTimeFormatter OFFSETTIME_DATASTORE_PARSER =
              DateTimeFormatter.ofPattern("HH:mm:ss" + FRACTIONAL_SECONDS_READ_PATTERN + "[ XXX]");
  
      private static final DateTimeFormatter OFFSETDATETIME_DATASTORE_FORMATTER =
              DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSSSSSSSS XXX");
  
      private static final DateTimeFormatter OFFSETDATETIME_DATASTORE_PARSER =
              DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss" + FRACTIONAL_SECONDS_READ_PATTERN + "[ XXX]");
  
      private static final DateTimeFormatter ZONEDDATETIME_DATASTORE_FORMATTER =
              DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSSSSSSSS VV");
  
      private static final DateTimeFormatter ZONEDDATETIME_DATASTORE_PARSER =
              DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss" + FRACTIONAL_SECONDS_READ_PATTERN + "[ VV]");
  
      /**
       * Returns a {@link String} representing given temporal suitable for the data-store.
       */
      @Nullable
      public String enstringOffsetTime(final @Nullable OffsetTime temporal) {
          return temporal != null
                  ? temporal.format(OFFSETTIME_DATASTORE_FORMATTER)
                  : null;
      }
  
      /**
       * Recovers a temporal from given {@link String}.
       */
      @Nullable
      public OffsetTime destringAsOffsetTime(final @Nullable String datastoreValue) {
          return _Strings.isNotEmpty(datastoreValue)
                  ? hasZoneOrOffsetInfoWhenAssumingTimeOnly(datastoreValue)
                          ? OffsetTime.parse(datastoreValue, OFFSETTIME_DATASTORE_PARSER)
                          : OffsetTime.of(
                                  LocalTime.parse(datastoreValue,
                                          OFFSETTIME_DATASTORE_PARSER), ZoneOffset.UTC)
                  : null;
      }
  
      /**
       * Returns a {@link String} representing given temporal suitable for the data-store.
       */
      @Nullable
      public String enstringOffsetDateTime(final @Nullable OffsetDateTime temporal) {
          return temporal != null
                  ? temporal.format(OFFSETDATETIME_DATASTORE_FORMATTER)
                  : null;
      }
  
      /**
       * Recovers a temporal from given {@link String}.
       */
      @Nullable
      public OffsetDateTime destringAsOffsetDateTime(final @Nullable String datastoreValue) {
          return _Strings.isNotEmpty(datastoreValue)
                  ? hasZoneOrOffsetInfoWhenAssumingDateAndTime(datastoreValue)
                          ? OffsetDateTime.parse(datastoreValue, OFFSETDATETIME_DATASTORE_PARSER)
                          : OffsetDateTime.of(
                                  LocalDateTime.parse(datastoreValue,
                                          OFFSETDATETIME_DATASTORE_PARSER), ZoneOffset.UTC)
                  : null;
      }
  
      /**
       * Returns a {@link String} representing given temporal suitable for the data-store.
       */
      @Nullable
      public String enstringZonedDateTime(final @Nullable ZonedDateTime temporal) {
          return temporal != null
                  ? temporal.format(ZONEDDATETIME_DATASTORE_FORMATTER)
                  : null;
      }
  
      /**
       * Recovers a temporal from given {@link String}.
       */
      @Nullable
      public ZonedDateTime destringAsZonedDateTime(final @Nullable String datastoreValue) {
          return _Strings.isNotEmpty(datastoreValue)
                  ? hasZoneOrOffsetInfoWhenAssumingDateAndTime(datastoreValue)
                          ? ZonedDateTime.parse(datastoreValue, ZONEDDATETIME_DATASTORE_PARSER)
                          : ZonedDateTime.of(
                                  LocalDateTime.parse(datastoreValue,
                                          ZONEDDATETIME_DATASTORE_PARSER), UTC)
                  : null;
      }
  
      // -- ISO UTILS
  
      public static OffsetDateTime parseIsoDateTime(final String isoDateTime) {
          return DateTimeFormatter.ISO_DATE_TIME.parse(isoDateTime, OffsetDateTime::from);
      }
  
      // -- TEMPORAL SAMPLERS
  
      public Can<LocalDateTime> sampleLocalDateTime() {
          return Can.of(
                  LocalDateTime.now(),
                  LocalDateTime.now().plusDays(2).plusSeconds(15));
      }
  
      public Can<LocalDate> sampleLocalDate() {
          return Can.of(
                  LocalDate.now(),
                  LocalDate.now().plusDays(2));
      }
  
      public Can<LocalTime> sampleLocalTime() {
          return Can.of(
                  LocalTime.now(),
                  LocalTime.now().plusSeconds(15));
      }
  
      public Can<ZonedDateTime> sampleZonedDateTime() {
          // don't depend on current TimeZone.getDefault(),
          // instead use an arbitrary mix of fixed time-zone offsets Z, +02:00 and -02:00
          var localNow = LocalDateTime.now();
          return Can.of(
                  ZonedDateTime.of(localNow, ZoneId.of("Europe/Paris")),
                  ZonedDateTime.of(localNow, ZoneOffset.UTC),
                  ZonedDateTime.of(localNow, ZoneId.of("UTC")),
                  ZonedDateTime.of(localNow, ZoneOffset.ofHours(2)),
                  ZonedDateTime.of(localNow, ZoneOffset.ofHours(-2)).plusDays(2).plusSeconds(15));
      }
  
      public Can<OffsetTime> sampleOffsetTime() {
          // don't depend on current TimeZone.getDefault(),
          // instead use an arbitrary mix of fixed time-zone offsets Z, +02:00 and -02:00
          var localNow = LocalTime.now();
          return Can.of(
                  OffsetTime.of(localNow, ZoneOffset.UTC),
                  OffsetTime.of(localNow, ZoneOffset.ofHours(2)),
                  OffsetTime.of(localNow, ZoneOffset.ofHours(-2)).plusSeconds(15));
      }
  
      public Can<OffsetDateTime> sampleOffsetDateTime() {
          // don't depend on current TimeZone.getDefault(),
          // instead use an arbitrary mix of fixed time-zone offsets Z, +02:00 and -02:00
          var localNow = LocalDateTime.now();
          return Can.of(
                  OffsetDateTime.of(localNow, ZoneOffset.UTC),
                  OffsetDateTime.of(localNow, ZoneOffset.ofHours(2)),
                  OffsetDateTime.of(localNow, ZoneOffset.ofHours(-2)).plusDays(2).plusSeconds(15));
      }
  
      // -- HELPER
  
      private BigDecimal millisToSeconds(final long millis) {
          return new BigDecimal(millis)
                  .movePointLeft(3)
                  .setScale(3, RoundingMode.HALF_EVEN);
      }
  
      /**
       * Whether the number of delimiting white-spaces hints at presence of zone/offset info.
       */
      private boolean hasZoneOrOffsetInfoWhenAssumingTimeOnly(final @NonNull String datastoreValue) {
          return delimitedChunksCount(datastoreValue)>1;
      }
  
      /**
       * Whether the number of delimiting white-spaces hints at presence of zone/offset info.
       */
      private boolean hasZoneOrOffsetInfoWhenAssumingDateAndTime(final @NonNull String datastoreValue) {
          return delimitedChunksCount(datastoreValue)>2;
      }
  
      private final Pattern DELIMITING_WHITESPACE_PATTERN = Pattern.compile("\\s+");
  
      private long delimitedChunksCount(final @NonNull String datastoreValue) {
          return _Strings.splitThenStream(datastoreValue, DELIMITING_WHITESPACE_PATTERN)
                  .filter(_Strings::isNotEmpty)
                  .count();
      }
  
  }
  