#include <Common/config.h>

#if USE_AWS_S3

#include <IO/S3Common.h>
#include <Storages/StorageFactory.h>
#include <Storages/StorageS3.h>
#include <Storages/StorageS3Settings.h>

#include <Interpreters/Context.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <Parsers/ASTLiteral.h>

#include <IO/ReadBufferFromS3.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteBufferFromS3.h>
#include <IO/WriteHelpers.h>

#include <Formats/FormatFactory.h>

#include <DataStreams/IBlockOutputStream.h>
#include <DataStreams/AddingDefaultsBlockInputStream.h>
#include <DataStreams/narrowBlockInputStreams.h>

#include <DataTypes/DataTypeString.h>

#include <aws/core/auth/AWSCredentials.h>
#include <aws/s3/S3Client.h>
#include <aws/s3/model/ListObjectsV2Request.h>

#include <Common/parseGlobs.h>
#include <Common/quoteString.h>
#include <re2/re2.h>

#include <Processors/Sources/SourceWithProgress.h>
#include <Processors/Formats/InputStreamFromInputFormat.h>
#include <Processors/Pipe.h>


namespace DB
{
namespace ErrorCodes
{
    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
    extern const int UNEXPECTED_EXPRESSION;
    extern const int S3_ERROR;
}

class StorageS3Source::DisclosedGlobIterator::Impl
{

public:
    Impl(Aws::S3::S3Client & client_, const S3::URI & globbed_uri_)
        : client(client_), globbed_uri(globbed_uri_) {

        if (globbed_uri.bucket.find_first_of("*?{") != globbed_uri.bucket.npos)
            throw Exception("Expression can not have wildcards inside bucket name", ErrorCodes::UNEXPECTED_EXPRESSION);

        const String key_prefix = globbed_uri.key.substr(0, globbed_uri.key.find_first_of("*?{"));

        if (key_prefix.size() == globbed_uri.key.size())
            buffer.emplace_back(globbed_uri.key);

        request.SetBucket(globbed_uri.bucket);
        request.SetPrefix(key_prefix);

        matcher = std::make_unique<re2::RE2>(makeRegexpPatternFromGlobs(globbed_uri.key));

        /// Don't forget about iterator invalidation
        buffer_iter = buffer.begin();
    }

    std::optional<String> next()
    {
        if (buffer_iter != buffer.end())
        {
            auto answer = *buffer_iter;
            ++buffer_iter;
            return answer;
        }

        if (is_finished)
            return std::nullopt; // Or throw?

        fillInternalBuffer();

        return next();
    }

private:

    void fillInternalBuffer()
    {
        buffer.clear();

        outcome = client.ListObjectsV2(request);
        if (!outcome.IsSuccess())
            throw Exception(ErrorCodes::S3_ERROR, "Could not list objects in bucket {} with prefix {}, S3 exception: {}, message: {}",
                            quoteString(request.GetBucket()), quoteString(request.GetPrefix()),
                            backQuote(outcome.GetError().GetExceptionName()), quoteString(outcome.GetError().GetMessage()));

        const auto & result_batch = outcome.GetResult().GetContents();

        buffer.reserve(result_batch.size());
        for (const auto & row : result_batch)
        {
            String key = row.GetKey();
            if (re2::RE2::FullMatch(key, *matcher))
                buffer.emplace_back(std::move(key));
        }
        /// Set iterator only after the whole batch is processed
        buffer_iter = buffer.begin();

        request.SetContinuationToken(outcome.GetResult().GetNextContinuationToken());
        
        /// It returns false when all objects were returned
        is_finished = !outcome.GetResult().GetIsTruncated();
    }

    Strings buffer;
    Strings::iterator buffer_iter;
    Aws::S3::S3Client client;
    S3::URI globbed_uri;
    Aws::S3::Model::ListObjectsV2Request request;
    Aws::S3::Model::ListObjectsV2Outcome outcome;
    std::unique_ptr<re2::RE2> matcher;
    bool is_finished{false};
};

StorageS3Source::DisclosedGlobIterator::DisclosedGlobIterator(Aws::S3::S3Client & client_, const S3::URI & globbed_uri_)
    : pimpl(std::make_unique<StorageS3Source::DisclosedGlobIterator::Impl>(client_, globbed_uri_)) {}

std::optional<String> StorageS3Source::DisclosedGlobIterator::next()
{
    return pimpl->next();
}


Block StorageS3Source::getHeader(Block sample_block, bool with_path_column, bool with_file_column)
{
    if (with_path_column)
        sample_block.insert({DataTypeString().createColumn(), std::make_shared<DataTypeString>(), "_path"});
    if (with_file_column)
        sample_block.insert({DataTypeString().createColumn(), std::make_shared<DataTypeString>(), "_file"});

    return sample_block;
}

StorageS3Source::StorageS3Source(
    bool need_path,
    bool need_file,
    const String & format_,
    String name_,
    const Block & sample_block_,
    const Context & context_,
    const ColumnsDescription & columns_,
    UInt64 max_block_size_,
    const String compression_hint_,
    const std::shared_ptr<Aws::S3::S3Client> & client_,
    const String & bucket_,
    std::shared_ptr<FileIterator> file_iterator_)
    : SourceWithProgress(getHeader(sample_block_, need_path, need_file))
    , name(std::move(name_))
    , bucket(bucket_)
    , format(format_)
    , context(context_)
    , columns_desc(columns_)
    , max_block_size(max_block_size_)
    , compression_hint(compression_hint_)
    , client(client_)
    , sample_block(sample_block_)
    , with_file_column(need_file)
    , with_path_column(need_path)
    , file_iterator(file_iterator_)
{
    initialize();
}


bool StorageS3Source::initialize()
{
    String current_key;
    if (auto result = file_iterator->next())
    {
        current_key = result.value();
        if (current_key.empty()) {
            return false;
        }
        file_path = bucket + "/" + current_key;
    }
    else
    {
        /// Do not initialize read_buffer and stream.
        return false;
    }

    read_buf = wrapReadBufferWithCompressionMethod(
        std::make_unique<ReadBufferFromS3>(client, bucket, current_key), chooseCompressionMethod(current_key, compression_hint));
    auto input_format = FormatFactory::instance().getInput(format, *read_buf, sample_block, context, max_block_size);
    reader = std::make_shared<InputStreamFromInputFormat>(input_format);

    if (columns_desc.hasDefaults())
        reader = std::make_shared<AddingDefaultsBlockInputStream>(reader, columns_desc, context);

    initialized = false;
    return true;
}

String StorageS3Source::getName() const
{
    return name;
}

Chunk StorageS3Source::generate()
{
    if (!reader)
        return {};

    if (!initialized)
    {
        reader->readPrefix();
        initialized = true;
    }

    if (auto block = reader->read())
    {
        auto columns = block.getColumns();
        UInt64 num_rows = block.rows();

        if (with_path_column)
            columns.push_back(DataTypeString().createColumnConst(num_rows, file_path)->convertToFullColumnIfConst());
        if (with_file_column)
        {
            size_t last_slash_pos = file_path.find_last_of('/');
            columns.push_back(DataTypeString().createColumnConst(num_rows, file_path.substr(
                    last_slash_pos + 1))->convertToFullColumnIfConst());
        }

        return Chunk(std::move(columns), num_rows);
    }

    reader->readSuffix();
    reader.reset();
    read_buf.reset();

    if (!initialize())
        return {};

    return generate();
}

namespace 
{
   class StorageS3BlockOutputStream : public IBlockOutputStream
    {
    public:
        StorageS3BlockOutputStream(
            const String & format,
            const Block & sample_block_,
            ContextPtr context,
            const CompressionMethod compression_method,
            const std::shared_ptr<Aws::S3::S3Client> & client,
            const String & bucket,
            const String & key,
            size_t min_upload_part_size,
            size_t max_single_part_upload_size)
            : sample_block(sample_block_)
        {
            write_buf = wrapWriteBufferWithCompressionMethod(
                std::make_unique<WriteBufferFromS3>(client, bucket, key, min_upload_part_size, max_single_part_upload_size), compression_method, 3);
            writer = FormatFactory::instance().getOutputStreamParallelIfPossible(format, *write_buf, sample_block, context);
        }

        Block getHeader() const override
        {
            return sample_block;
        }

        void write(const Block & block) override
        {
            writer->write(block);
        }

        void writePrefix() override
        {
            writer->writePrefix();
        }

        void flush() override
        {
            writer->flush();
        }

        void writeSuffix() override
        {
            writer->writeSuffix();
            writer->flush();
            write_buf->finalize();
        }

    private:
        Block sample_block;
        std::unique_ptr<WriteBuffer> write_buf;
        BlockOutputStreamPtr writer;
    };
}


StorageS3::StorageS3(
    const S3::URI & uri_,
    const String & access_key_id_,
    const String & secret_access_key_,
    const StorageID & table_id_,
    const String & format_name_,
    UInt64 min_upload_part_size_,
    UInt64 max_single_part_upload_size_,
    UInt64 max_connections_,
    const ColumnsDescription & columns_,
    const ConstraintsDescription & constraints_,
    ContextPtr context_,
    const String & compression_method_)
    : IStorage(table_id_)
    , client_auth{uri_, access_key_id_, secret_access_key_, max_connections_, {}, {}} /// Client and settings will be updated later
    , format_name(format_name_)
    , min_upload_part_size(min_upload_part_size_)
    , max_single_part_upload_size(max_single_part_upload_size_)
    , compression_method(compression_method_)
    , name(uri_.storage_name)
{
    context_->getGlobalContext()->getRemoteHostFilter().checkURL(uri_.uri);
    StorageInMemoryMetadata storage_metadata;
    storage_metadata.setColumns(columns_);
    storage_metadata.setConstraints(constraints_);
    setInMemoryMetadata(storage_metadata);
    updateClientAndAuthSettings(context_, client_auth);
}


Pipe StorageS3::read(
    const Names & column_names,
    const StorageMetadataPtr & metadata_snapshot,
    SelectQueryInfo & /*query_info*/,
    ContextPtr local_context,
    QueryProcessingStage::Enum /*processed_stage*/,
    size_t max_block_size,
    unsigned num_streams)
{
    updateClientAndAuthSettings(local_context, client_auth);

    Pipes pipes;
    bool need_path_column = false;
    bool need_file_column = false;
    for (const auto & column : column_names)
    {
        if (column == "_path")
            need_path_column = true;
        if (column == "_file")
            need_file_column = true;
    }

    /// Iterate through disclosed globs and make a source for each file
    StorageS3Source::DisclosedGlobIterator glob_iterator(*client_auth.client, client_auth.uri);

    auto file_iterator = std::make_shared<LocalFileIterator>(glob_iterator);
    for (size_t i = 0; i < num_streams; ++i)
    {
        pipes.emplace_back(std::make_shared<StorageS3Source>(
            need_path_column,
            need_file_column,
            format_name,
            getName(),
            metadata_snapshot->getSampleBlock(),
            local_context,
            metadata_snapshot->getColumns(),
            max_block_size,
            compression_method,
            client_auth.client,
            client_auth.uri.bucket,
            file_iterator));
    }
    return Pipe::unitePipes(std::move(pipes));
}

BlockOutputStreamPtr StorageS3::write(const ASTPtr & /*query*/, const StorageMetadataPtr & metadata_snapshot, ContextPtr local_context)
{
    updateClientAndAuthSettings(local_context, client_auth);
    return std::make_shared<StorageS3BlockOutputStream>(
        format_name,
        metadata_snapshot->getSampleBlock(),
        context,
        chooseCompressionMethod(client_auth.uri.key, compression_method),
        client_auth.client,
        client_auth.uri.bucket,
        client_auth.uri.key,
        min_upload_part_size,
        max_single_part_upload_size);
}

void StorageS3::updateClientAndAuthSettings(ContextPtr ctx, StorageS3::ClientAuthentificaiton & upd)
{
    auto settings = ctx->getStorageS3Settings().getSettings(upd.uri.uri.toString());
    if (upd.client && (!upd.access_key_id.empty() || settings == upd.auth_settings))
        return;

    Aws::Auth::AWSCredentials credentials(upd.access_key_id, upd.secret_access_key);
    HeaderCollection headers;
    if (upd.access_key_id.empty())
    {
        credentials = Aws::Auth::AWSCredentials(settings.access_key_id, settings.secret_access_key);
        headers = settings.headers;
    }

    S3::PocoHTTPClientConfiguration client_configuration = S3::ClientFactory::instance().createClientConfiguration(
        ctx->getRemoteHostFilter(), ctx->getGlobalContext()->getSettingsRef().s3_max_redirects);

    client_configuration.endpointOverride = upd.uri.endpoint;
    client_configuration.maxConnections = upd.max_connections;

    upd.client = S3::ClientFactory::instance().create(
        client_configuration,
        upd.uri.is_virtual_hosted_style,
        credentials.GetAWSAccessKeyId(),
        credentials.GetAWSSecretKey(),
        settings.server_side_encryption_customer_key_base64,
        std::move(headers),
        settings.use_environment_credentials.value_or(ctx->getConfigRef().getBool("s3.use_environment_credentials", false)));

    upd.auth_settings = std::move(settings);
}

void registerStorageS3Impl(const String & name, StorageFactory & factory)
{
    factory.registerStorage(name, [](const StorageFactory::Arguments & args)
    {
        ASTs & engine_args = args.engine_args;

        if (engine_args.size() < 2 || engine_args.size() > 5)
            throw Exception(
                "Storage S3 requires 2 to 5 arguments: url, [access_key_id, secret_access_key], name of used format and [compression_method].",
                ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);

        for (auto & engine_arg : engine_args)
            engine_arg = evaluateConstantExpressionOrIdentifierAsLiteral(engine_arg, args.getLocalContext());

        String url = engine_args[0]->as<ASTLiteral &>().value.safeGet<String>();
        Poco::URI uri (url);
        S3::URI s3_uri (uri);

        String access_key_id;
        String secret_access_key;
        if (engine_args.size() >= 4)
        {
            access_key_id = engine_args[1]->as<ASTLiteral &>().value.safeGet<String>();
            secret_access_key = engine_args[2]->as<ASTLiteral &>().value.safeGet<String>();
        }

        UInt64 min_upload_part_size = args.getLocalContext()->getSettingsRef().s3_min_upload_part_size;
        UInt64 max_single_part_upload_size = args.getLocalContext()->getSettingsRef().s3_max_single_part_upload_size;
        UInt64 max_connections = args.getLocalContext()->getSettingsRef().s3_max_connections;

        String compression_method;
        String format_name;
        if (engine_args.size() == 3 || engine_args.size() == 5)
        {
            compression_method = engine_args.back()->as<ASTLiteral &>().value.safeGet<String>();
            format_name = engine_args[engine_args.size() - 2]->as<ASTLiteral &>().value.safeGet<String>();
        }
        else
        {
            compression_method = "auto";
            format_name = engine_args.back()->as<ASTLiteral &>().value.safeGet<String>();
        }

        return StorageS3::create(
            s3_uri,
            access_key_id,
            secret_access_key,
            args.table_id,
            format_name,
            min_upload_part_size,
            max_single_part_upload_size,
            max_connections,
            args.columns,
            args.constraints,
            args.getContext(),
            compression_method
        );
    },
    {
        .source_access_type = AccessType::S3,
    });
}

void registerStorageS3(StorageFactory & factory)
{
    return registerStorageS3Impl("S3", factory);
}

void registerStorageCOS(StorageFactory & factory)
{
    return registerStorageS3Impl("COSN", factory);
}

NamesAndTypesList StorageS3::getVirtuals() const
{
    return NamesAndTypesList{
        {"_path", std::make_shared<DataTypeString>()},
        {"_file", std::make_shared<DataTypeString>()}
    };
}

}

#endif