// 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 <stddef.h>

#include <atomic>

#include <condition_variable>

#include <list>

#include <memory>

#include <mutex>

#include <utility>

#include <vector>

#include "common/status.h"

#include "gutil/ref_counted.h"

#include "pipeline_task.h"

#include "runtime/task_group/task_group.h"

#include "util/thread.h"

namespace doris {

class ExecEnv;

class ThreadPool;

namespace pipeline {

class TaskQueue;

} // namespace pipeline

} // namespace doris

namespace doris::pipeline {

class BlockedTaskScheduler {

public:

    explicit BlockedTaskScheduler(std::shared_ptr<TaskQueue> task_queue);

    ~BlockedTaskScheduler() = default;

    Status start();

    void shutdown();

    Status add_blocked_task(PipelineTask* task);

private:

    std::shared_ptr<TaskQueue> _task_queue;

    std::mutex _task_mutex;

    std::condition_variable _task_cond;

    std::list<PipelineTask*> _blocked_tasks;

    scoped_refptr<Thread> _thread;

    std::atomic<bool> _started;

    std::atomic<bool> _shutdown;

    static constexpr auto EMPTY_TIMES_TO_YIELD = 64;

private:

    void _schedule();

    void _make_task_run(std::list<PipelineTask*>& local_tasks,

                        std::list<PipelineTask*>::iterator& task_itr,

                        PipelineTaskState state = PipelineTaskState::RUNNABLE);

};

class TaskScheduler {

public:

    TaskScheduler(ExecEnv* exec_env, std::shared_ptr<BlockedTaskScheduler> b_scheduler,

                  std::shared_ptr<TaskQueue> task_queue, std::string name)

            : _task_queue(std::move(task_queue)),

              _blocked_task_scheduler(std::move(b_scheduler)),

              _shutdown(false),

              _name(name) {}

    ~TaskScheduler();

    Status schedule_task(PipelineTask* task);

    Status start();

    void shutdown();

    TaskQueue* task_queue() const { return _task_queue.get(); }

private:

    std::unique_ptr<ThreadPool> _fix_thread_pool;

    std::shared_ptr<TaskQueue> _task_queue;

    std::vector<std::unique_ptr<std::atomic<bool>>> _markers;

    std::shared_ptr<BlockedTaskScheduler> _blocked_task_scheduler;

    std::atomic<bool> _shutdown;

    std::string _name;

    void _do_work(size_t index);

    // after _try_close_task, task maybe destructed.

    void _try_close_task(PipelineTask* task, PipelineTaskState state);

};

} // namespace doris::pipeline