package de.ph87.data.series;

import lombok.*;

import java.time.*;
import java.time.temporal.*;
import java.util.function.*;

public enum Alignment {
  FIVE(t -> t.truncatedTo(ChronoUnit.MINUTES).minusMinutes(t.getMinute() % 5), Duration.ofMinutes(5), Duration.ofMinutes(5)),
  HOUR(t -> t.truncatedTo(ChronoUnit.HOURS), Duration.ofHours(1), Duration.ofHours(1)),
  DAY(t -> t.truncatedTo(ChronoUnit.DAYS), Duration.ofDays(1), Duration.ofDays(1)),
  WEEK(t -> t.truncatedTo(ChronoUnit.DAYS).minusDays(t.getDayOfWeek().getValue() - 1), Period.ofWeeks(1), Duration.ofDays(7)),
  MONTH(t -> t.truncatedTo(ChronoUnit.DAYS).minusDays(t.getDayOfMonth() - 1), Period.ofMonths(1), Duration.ofDays(31)),
  YEAR(t -> t.truncatedTo(ChronoUnit.DAYS).minusDays(t.getDayOfYear() - 1), Period.ofYears(1), Duration.ofDays(366)),
  ;

  @NonNull
  public final Function<ZonedDateTime, ZonedDateTime> align;

  @NonNull
  public final TemporalAmount amount;

  @NonNull
  public final Duration maxDuration;

  Alignment(@NonNull final Function<@NonNull ZonedDateTime, @NonNull ZonedDateTime> align, @NonNull final TemporalAmount amount, @NonNull final Duration maxDuration) {
    this.maxDuration = maxDuration;
    this.align = align;
    this.amount = amount;
  }

  @NonNull
  public Aligned align(@NonNull final ZonedDateTime date) {
    return new Aligned(this, date);
  }

  @NonNull
  public ZonedDateTime plus(@NonNull final ZonedDateTime date, final long amount) {
    return date.plus(multiplyAmount(amount));
  }

  @NonNull
  @SuppressWarnings("unused")
  public ZonedDateTime minus(@NonNull final ZonedDateTime date, final long amount) {
    return plus(date, -amount);
  }

  @NonNull
  public TemporalAmount multiplyAmount(final long amount) {
    if (this.amount instanceof final Duration duration) {
      return duration.multipliedBy(amount);
    } else if (this.amount instanceof final Period period) {
      return period.multipliedBy((int) amount);
    }
    throw new RuntimeException("Cannot multiply unimplemented TemporalAmount: %s".formatted(this.amount));
  }

}