/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.snapshots;

import org.elasticsearch.TransportVersions;
import org.elasticsearch.cluster.metadata.ProjectId;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.io.stream.Writeable;
import org.elasticsearch.core.FixForMultiProject;

import java.io.IOException;
import java.util.Objects;

/**
 * Basic information about a snapshot - a SnapshotId and the repository that the snapshot belongs to.
 */
public final class Snapshot implements Writeable {

    private final ProjectId projectId;
    private final String repository;
    private final SnapshotId snapshotId;
    private final int hashCode;

    /**
     * Constructs a snapshot.
     */
    @FixForMultiProject
    @Deprecated(forRemoval = true)
    public Snapshot(final String repository, final SnapshotId snapshotId) {
        this(ProjectId.DEFAULT, repository, snapshotId);
    }

    /**
     * Constructs a snapshot.
     */
    public Snapshot(ProjectId projectId, final String repository, final SnapshotId snapshotId) {
        this.projectId = projectId;
        this.repository = Objects.requireNonNull(repository);
        this.snapshotId = Objects.requireNonNull(snapshotId);
        this.hashCode = computeHashCode();
    }

    /**
     * Constructs a snapshot from the stream input.
     */
    public Snapshot(final StreamInput in) throws IOException {
        if (in.getTransportVersion().before(TransportVersions.PROJECT_ID_IN_SNAPSHOT)) {
            projectId = ProjectId.DEFAULT;
        } else {
            projectId = ProjectId.readFrom(in);
        }
        repository = in.readString();
        snapshotId = new SnapshotId(in);
        hashCode = computeHashCode();
    }

    public ProjectId getProjectId() {
        return projectId;
    }

    /**
     * Gets the repository name for the snapshot.
     */
    public String getRepository() {
        return repository;
    }

    /**
     * Gets the snapshot id for the snapshot.
     */
    public SnapshotId getSnapshotId() {
        return snapshotId;
    }

    @Override
    public String toString() {
        return projectId + ":" + repository + ":" + snapshotId.toString();
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        Snapshot that = (Snapshot) o;
        return projectId.equals(that.projectId) && repository.equals(that.repository) && snapshotId.equals(that.snapshotId);
    }

    @Override
    public int hashCode() {
        return hashCode;
    }

    private int computeHashCode() {
        return Objects.hash(projectId, repository, snapshotId);
    }

    @Override
    public void writeTo(final StreamOutput out) throws IOException {
        if (out.getTransportVersion().before(TransportVersions.PROJECT_ID_IN_SNAPSHOT)) {
            if (ProjectId.DEFAULT.equals(projectId) == false) {
                final var message = "Cannot write instance with non-default project id "
                    + projectId
                    + " to version before "
                    + TransportVersions.PROJECT_ID_IN_SNAPSHOT;
                assert false : message;
                throw new IllegalArgumentException(message);
            }
        } else {
            projectId.writeTo(out);
        }
        out.writeString(repository);
        snapshotId.writeTo(out);
    }

}