/*
 * 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.
 */

#pragma once

#include <cstdint>
#include <memory>

#include "paimon/core/mergetree/compact/sort_merge_reader.h"
#include "paimon/result.h"

namespace paimon {

/// Counts rows from a merged KeyValue stream after delete rows are dropped.
class RowCountAccumulator {
 public:
    /// @param merged_reader  The merged reader. Must be wrapped with DropDeleteReader
    ///                       so that only valid (non-deleted) KeyValue objects are output.
    explicit RowCountAccumulator(std::unique_ptr<SortMergeReader>&& merged_reader);

    ~RowCountAccumulator() = default;

    /// Count all valid rows from the merge reader.
    /// Iterates through all merged+deduplicated+non-deleted KeyValue objects.
    Result<int64_t> CountAll();

    /// Close underlying readers and release resources.
    void Close();

 private:
    std::unique_ptr<SortMergeReader> merged_reader_;
};

}  // namespace paimon
