/*
 * 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.beam.sdk.io.kinesis;


import static com.google.common.base.Preconditions.checkNotNull;

import com.amazonaws.services.kinesis.clientlibrary.lib.worker.InitialPositionInStream;
import com.amazonaws.services.kinesis.model.ShardIteratorType;
import java.io.Serializable;
import java.util.Objects;
import org.joda.time.Instant;

/**
 * Denotes a point at which the reader should start reading from a Kinesis stream.
 * It can be expressed either as an {@link InitialPositionInStream} enum constant or a timestamp,
 * in which case the reader will start reading at the specified point in time.
 */
class StartingPoint implements Serializable {
    private final InitialPositionInStream position;
    private final Instant timestamp;

    public StartingPoint(InitialPositionInStream position) {
        this.position = checkNotNull(position, "position");
        this.timestamp = null;
    }

    public StartingPoint(Instant timestamp) {
        this.timestamp = checkNotNull(timestamp, "timestamp");
        this.position = null;
    }

    public InitialPositionInStream getPosition() {
        return position;
    }

    public String getPositionName() {
        return position != null ? position.name() : ShardIteratorType.AT_TIMESTAMP.name();
    }

    public Instant getTimestamp() {
        return timestamp != null ? timestamp : null;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        StartingPoint that = (StartingPoint) o;
        return position == that.position && Objects.equals(timestamp, that.timestamp);
    }

    @Override
    public int hashCode() {
        return Objects.hash(position, timestamp);
    }

    @Override
    public String toString() {
        if (timestamp == null) {
            return position.toString();
        } else {
            return "Starting at timestamp " + timestamp;
        }
    }
}