/*
 * Copyright (c) 2024 Huawei Device Co., Ltd.
 * Licensed 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.
 */

#ifndef CORE_THREADING_DISPATHCER_TASK_QUEUE_H
#define CORE_THREADING_DISPATHCER_TASK_QUEUE_H

#include <deque>
#include <mutex>

#include <base/containers/string_view.h>
#include <base/containers/vector.h>
#include <core/namespace.h>
#include <core/threading/intf_thread_pool.h>

#include "threading/task_queue.h"

CORE_BEGIN_NAMESPACE()
// Thread safe task dispatcher, executes one task per execute call and removes it once it is finished.
class DispatcherTaskQueue final : public TaskQueue {
public:
    /** Constructor for the dispatcher task queue.
        @param threads Optional thread pool, if support for threading is desired.
    */
    explicit DispatcherTaskQueue(const IThreadPool::Ptr& threadPool);
    DispatcherTaskQueue(const DispatcherTaskQueue& other) = delete;
    ~DispatcherTaskQueue() override;

    /** Reports finished tasks, allows to check which tasks have been completed.
        @return Task ids of tasks that have finished.
    */
    BASE_NS::vector<uint64_t> CollectFinishedTasks();

    void Submit(uint64_t taskIdentifier, IThreadPool::ITask::Ptr&& task) override;
    void SubmitAfter(uint64_t afterIdentifier, uint64_t taskIdentifier, IThreadPool::ITask::Ptr&& task);
    void SubmitAfter(
        BASE_NS::array_view<const uint64_t> afterIdentifiers, uint64_t taskIdentifier, IThreadPool::ITask::Ptr&& task);
    void Remove(uint64_t taskIdentifier) override;

    void Clear() override;

    void Execute() override;

private:
    std::deque<Entry> tasks_;
    BASE_NS::vector<Entry> finishedTasks_;
    std::mutex queueLock_;
};
CORE_END_NAMESPACE()

#endif // CORE_THREADING_DISPATHCER_TASK_QUEUE_H