/*
 * Copyright 2020 NEM
 *
 * Licensed 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 io.nem.symbol.sdk.model.transaction;

import java.math.BigInteger;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.temporal.ChronoUnit;

/**
 * The deadline of the transaction. The deadline is given as the number of seconds elapsed since the
 * creation of the nemesis block. If a transaction does not get included in a block before the
 * deadline is reached, it is deleted.
 *
 * @since 1.0
 */
public class Deadline {

    /**
     * Nemesis block timestamp.
     */
    private static final Instant TIMESTAMP_NEMESIS_BLOCK = Instant.ofEpochSecond(1573430400);

    private final Instant instant;

    /**
     * Constructor
     *
     * @param units int
     * @param chronoUnit Chrono unit
     */
    public Deadline(int units, ChronoUnit chronoUnit) {
        instant = Instant.now().plus(units, chronoUnit);
    }

    /**
     * Constructor
     *
     * @param input Deadline in BigInteger format
     */
    public Deadline(BigInteger input) {
        instant =
            Instant
                .ofEpochMilli(input.longValue() + Deadline.TIMESTAMP_NEMESIS_BLOCK.toEpochMilli());
    }

    /**
     * @return the BigInteger representation of the duration.
     */
    public BigInteger toBigInteger() {
        return BigInteger.valueOf(getInstant());
    }

    /**
     * Create deadline model.
     *
     * @param units int
     * @param chronoUnit Chrono unit
     * @return {@link Deadline}
     */
    public static Deadline create(int units, ChronoUnit chronoUnit) {
        return new Deadline(units, chronoUnit);
    }

    /**
     * Create the default deadline of 2 hours.
     *
     * @return {@link Deadline}
     */
    public static Deadline create() {
        return new Deadline(2, ChronoUnit.HOURS);
    }

    /**
     * Returns number of seconds elapsed since the creation of the nemesis block.
     *
     * @return long
     */
    public long getInstant() {
        return instant.toEpochMilli() - Deadline.TIMESTAMP_NEMESIS_BLOCK.toEpochMilli();
    }

    /**
     * Returns deadline as local date time in a given timezone.
     *
     * @param zoneId Timezone
     * @return LocalDateTime
     */
    public LocalDateTime getLocalDateTime(ZoneId zoneId) {
        return LocalDateTime.ofInstant(instant, zoneId);
    }

    /**
     * Returns deadline as local date time.
     *
     * @return LocalDateTime
     */
    public LocalDateTime getLocalDateTime() {
        return getLocalDateTime(ZoneId.systemDefault());
    }
}