/*
 * 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.repositories.azure;

import com.azure.core.exception.HttpResponseException;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.elasticsearch.ExceptionsHelper;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.blobstore.BlobContainer;
import org.elasticsearch.common.blobstore.BlobPath;
import org.elasticsearch.common.blobstore.DeleteResult;
import org.elasticsearch.common.blobstore.OperationPurpose;
import org.elasticsearch.common.blobstore.OptionalBytesReference;
import org.elasticsearch.common.blobstore.support.AbstractBlobContainer;
import org.elasticsearch.common.blobstore.support.BlobMetadata;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.core.CheckedConsumer;
import org.elasticsearch.core.Nullable;
import org.elasticsearch.repositories.blobstore.RequestedRangeNotSatisfiedException;
import org.elasticsearch.rest.RestStatus;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.NoSuchFileException;
import java.util.Iterator;
import java.util.Map;

public class AzureBlobContainer extends AbstractBlobContainer {

    private static final Logger logger = LogManager.getLogger(AzureBlobContainer.class);
    private final AzureBlobStore blobStore;
    private final String keyPath;

    AzureBlobContainer(BlobPath path, AzureBlobStore blobStore) {
        super(path);
        this.blobStore = blobStore;
        this.keyPath = path.buildAsString();
    }

    @Override
    public boolean blobExists(OperationPurpose purpose, String blobName) throws IOException {
        logger.trace("blobExists({})", blobName);
        return blobStore.blobExists(purpose, buildKey(blobName));
    }

    private InputStream openInputStream(OperationPurpose purpose, String blobName, long position, @Nullable Long length)
        throws IOException {
        String blobKey = buildKey(blobName);
        logger.trace("readBlob({}) from position [{}] with length [{}]", blobName, position, length != null ? length : "unlimited");
        if (blobStore.getLocationMode() == LocationMode.SECONDARY_ONLY && blobExists(purpose, blobName) == false) {
            // On Azure, if the location path is a secondary location, and the blob does not
            // exist, instead of returning immediately from the getInputStream call below
            // with a 404 StorageException, Azure keeps trying and trying for a long timeout
            // before throwing a storage exception. This can cause long delays in retrieving
            // snapshots, so we first check if the blob exists before trying to open an input
            // stream to it.
            throw new NoSuchFileException("Blob [" + blobKey + "] not found");
        }
        try {
            return blobStore.getInputStream(purpose, blobKey, position, length);
        } catch (Exception e) {
            if (ExceptionsHelper.unwrap(e, HttpResponseException.class) instanceof HttpResponseException httpResponseException) {
                final var httpStatusCode = httpResponseException.getResponse().getStatusCode();
                if (httpStatusCode == RestStatus.NOT_FOUND.getStatus()) {
                    throw new NoSuchFileException("Blob [" + blobKey + "] not found");
                }
                if (httpStatusCode == RestStatus.REQUESTED_RANGE_NOT_SATISFIED.getStatus()) {
                    throw new RequestedRangeNotSatisfiedException(blobKey, position, length == null ? -1 : length, e);
                }
            }
            throw new IOException("Unable to get input stream for blob [" + blobKey + "]", e);
        }
    }

    @Override
    public InputStream readBlob(OperationPurpose purpose, String blobName) throws IOException {
        return openInputStream(purpose, blobName, 0L, null);
    }

    @Override
    public InputStream readBlob(OperationPurpose purpose, String blobName, long position, long length) throws IOException {
        return openInputStream(purpose, blobName, position, length);
    }

    @Override
    public long readBlobPreferredLength() {
        return blobStore.getReadChunkSize();
    }

    @Override
    public void writeBlob(OperationPurpose purpose, String blobName, InputStream inputStream, long blobSize, boolean failIfAlreadyExists)
        throws IOException {
        logger.trace("writeBlob({}, stream, {})", buildKey(blobName), blobSize);
        blobStore.writeBlob(purpose, buildKey(blobName), inputStream, blobSize, failIfAlreadyExists);
    }

    @Override
    public boolean supportsConcurrentMultipartUploads() {
        return true;
    }

    @Override
    public void writeBlobAtomic(
        OperationPurpose purpose,
        String blobName,
        long blobSize,
        BlobMultiPartInputStreamProvider provider,
        boolean failIfAlreadyExists
    ) throws IOException {
        blobStore.writeBlobAtomic(purpose, buildKey(blobName), blobSize, provider, failIfAlreadyExists);
    }

    @Override
    public void writeBlobAtomic(
        OperationPurpose purpose,
        String blobName,
        InputStream inputStream,
        long blobSize,
        boolean failIfAlreadyExists
    ) throws IOException {
        writeBlob(purpose, blobName, inputStream, blobSize, failIfAlreadyExists);
    }

    @Override
    public void writeBlobAtomic(OperationPurpose purpose, String blobName, BytesReference bytes, boolean failIfAlreadyExists) {
        writeBlob(purpose, blobName, bytes, failIfAlreadyExists);
    }

    @Override
    public void writeBlob(OperationPurpose purpose, String blobName, BytesReference bytes, boolean failIfAlreadyExists) {
        blobStore.writeBlob(purpose, buildKey(blobName), bytes, failIfAlreadyExists);
    }

    @Override
    public void writeMetadataBlob(
        OperationPurpose purpose,
        String blobName,
        boolean failIfAlreadyExists,
        boolean atomic,
        CheckedConsumer<OutputStream, IOException> writer
    ) throws IOException {
        blobStore.writeBlob(purpose, buildKey(blobName), failIfAlreadyExists, writer);
    }

    @Override
    public DeleteResult delete(OperationPurpose purpose) throws IOException {
        return blobStore.deleteBlobDirectory(purpose, keyPath);
    }

    @Override
    public void deleteBlobsIgnoringIfNotExists(OperationPurpose purpose, Iterator<String> blobNames) throws IOException {
        blobStore.deleteBlobs(purpose, new Iterator<>() {
            @Override
            public boolean hasNext() {
                return blobNames.hasNext();
            }

            @Override
            public String next() {
                return buildKey(blobNames.next());
            }
        });
    }

    @Override
    public Map<String, BlobMetadata> listBlobsByPrefix(OperationPurpose purpose, @Nullable String prefix) throws IOException {
        logger.trace("listBlobsByPrefix({})", prefix);
        return blobStore.listBlobsByPrefix(purpose, keyPath, prefix);
    }

    @Override
    public Map<String, BlobMetadata> listBlobs(OperationPurpose purpose) throws IOException {
        logger.trace("listBlobs()");
        return listBlobsByPrefix(purpose, null);
    }

    @Override
    public Map<String, BlobContainer> children(OperationPurpose purpose) throws IOException {
        final BlobPath path = path();
        return blobStore.children(purpose, path);
    }

    protected String buildKey(String blobName) {
        return keyPath + (blobName == null ? "" : blobName);
    }

    private boolean skipRegisterOperation(ActionListener<?> listener) {
        return skipIfNotPrimaryOnlyLocationMode(listener);
    }

    private boolean skipIfNotPrimaryOnlyLocationMode(ActionListener<?> listener) {
        if (blobStore.getLocationMode() == LocationMode.PRIMARY_ONLY) {
            return false;
        }
        listener.onFailure(
            new UnsupportedOperationException(
                Strings.format("consistent register operations are not supported with location_mode [%s]", blobStore.getLocationMode())
            )
        );
        return true;
    }

    @Override
    public void getRegister(OperationPurpose purpose, String key, ActionListener<OptionalBytesReference> listener) {
        if (skipRegisterOperation(listener)) return;
        ActionListener.completeWith(listener, () -> blobStore.getRegister(purpose, buildKey(key), keyPath, key));
    }

    @Override
    public void compareAndExchangeRegister(
        OperationPurpose purpose,
        String key,
        BytesReference expected,
        BytesReference updated,
        ActionListener<OptionalBytesReference> listener
    ) {
        if (skipRegisterOperation(listener)) return;
        ActionListener.completeWith(
            listener,
            () -> blobStore.compareAndExchangeRegister(purpose, buildKey(key), keyPath, key, expected, updated)
        );
    }

    // visible for testing
    AzureBlobStore getBlobStore() {
        return blobStore;
    }
}