// 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 <stdint.h>

#include <functional>

#include "common/status.h"

#include "runtime/memory/mem_tracker.h"

#include "runtime/workload_group/workload_group.h"

#include "util/countdown_latch.h"

#include "util/stopwatch.hpp"

namespace doris {

class MemTableWriter;

struct WriterMemItem {

    std::weak_ptr<MemTableWriter> writer;

    int64_t mem_size;

};

class MemTableMemoryLimiter {

public:

    MemTableMemoryLimiter();

    ~MemTableMemoryLimiter();

    Status init(int64_t process_mem_limit);

    // check if the total mem consumption exceeds limit.

    // If yes, it will flush memtable to try to reduce memory consumption.

    // Every write operation will call this API to check if need flush memtable OR hang

    // when memory is not available.

    void handle_memtable_flush(std::function<bool()> cancel_check, WorkloadGroup* wg = nullptr);

    void handle_table_memtable_backpressure(std::function<bool()> cancel_check, int64_t table_id);

    void register_writer(std::weak_ptr<MemTableWriter> writer);

    void refresh_mem_tracker();

    MemTracker* mem_tracker() { return _mem_tracker.get(); }

    int64_t mem_usage() const { return _mem_usage; }

    bool soft_limit_reached() { return _soft_limit_reached(); }

private:

    static inline int64_t _sys_avail_mem_less_than_warning_water_mark();

    static inline int64_t _process_used_mem_more_than_soft_mem_limit();

    bool _soft_limit_reached();

    bool _hard_limit_reached();

    bool _load_usage_low();

    int64_t _need_flush();

    int64_t _table_flush_pending_memtable_count(int64_t table_id);

    int64_t _flush_active_memtables(int64_t need_flush);

    void _refresh_mem_tracker();

    std::mutex _lock;

    std::condition_variable _hard_limit_end_cond;

    int64_t _mem_usage = 0;

    int64_t _flush_mem_usage = 0;

    int64_t _queue_mem_usage = 0;

    int64_t _active_mem_usage = 0;

    // sum of all mem table memory.

    std::unique_ptr<MemTracker> _mem_tracker;

    int64_t _load_hard_mem_limit = -1;

    int64_t _load_soft_mem_limit = -1;

    int64_t _load_safe_mem_permit = -1;

    enum Limit { NONE, SOFT, HARD } _last_limit = Limit::NONE;

    MonotonicStopWatch _log_timer;

    static const int64_t LOG_INTERVAL = 1 * 1000 * 1000 * 1000; // 1s

    std::vector<std::weak_ptr<MemTableWriter>> _writers;

    std::vector<std::weak_ptr<MemTableWriter>> _active_writers;

};

} // namespace doris