/*************************************************************************
 *
 *  This file is part of the ACT library
 *
 *  Copyright (c) 2024 Fabian Posch
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA  02110-1301, USA.
 *
 **************************************************************************
 */

#ifndef __TASK_INTERFACE__
#define __TASK_INTERFACE__

#include <cstddef>
#include <queue>
#include <unordered_map>
#include <atomic>
#include <condition_variable>
#include <mutex>
#include <vector>
#include "agent_artifact.hpp"
#include <chrono>

/** 
 * If you want to use this interface for different types, you only need to change it here. 
 * This can be any type, as long as it publicly derives form pl::Artifact.
 */
using InputType = DBSimConfigArtifact;
using OutputType = DBSimOutputArtifact;

#define NOTHING_AVAILABLE_SLEEP_TIME 500ms

class TaskInterface {

    public:

    TaskInterface(size_t buffer_size);
    ~TaskInterface();

    void wait_for_fresh();
    void wait_for_finished(size_t min_size);
    void wait_for_buffer_consume();
    void wait_for_cleanup_ready();
    void wait_for_download_halt();
    void wait_for_available();
    
    void notify_cleanup_ready();
    void notify_workers_program_halt();
    void notify_download_halt();

    void push_fresh(std::unique_ptr<InputType> task);
    void push_fresh(std::vector<std::unique_ptr<InputType>>& tasks);
    std::unique_ptr<InputType> pop_fresh(bool& empty);
    void push_finished(std::unique_ptr<OutputType> task);
    std::vector<std::unique_ptr<OutputType>> pop_finished(bool& empty);
    size_t get_buffer_space();

    /*
     * Store a design entry locally
    */
    bool increment_design(const db::uuid_t& id);
    void decrement_design(const db::uuid_t& id);
    std::string get_design(const db::uuid_t& id);
    void store_design(const db::uuid_t&, std::string& design);

    /*
     * Store a reference run locally
    */
    bool increment_reference(const db::uuid_t& id);
    void decrement_reference(const db::uuid_t& id);
    std::shared_ptr<pl::SimOutputArtifact> get_reference(const db::uuid_t& id);
    void store_reference(const db::uuid_t&, std::shared_ptr<pl::SimOutputArtifact> reference_run);

    bool running() { return this->running_.load(std::memory_order_relaxed); };
    bool is_stop_immediate() { return this->immediate_stop.load(std::memory_order_relaxed); };
    void stop();
    void stop_immediately() { this->immediate_stop.store(true, std::memory_order_relaxed); };

    bool fresh_queue_empty();
    bool finished_queue_empty(size_t min_size);

    private:

    size_t buffer_size;

    std::queue<std::unique_ptr<InputType>> fresh_queue;
    std::queue<std::unique_ptr<OutputType>> finished_queue;

    volatile std::atomic_bool running_ = std::atomic_bool(true);
    volatile std::atomic_bool immediate_stop;

    std::unordered_map<db::uuid_t, std::pair<size_t, std::string>> designs;
    std::unordered_map<db::uuid_t, std::pair<size_t, std::shared_ptr<pl::SimOutputArtifact>>> references;

    bool worker_waiting = false;
    bool downloader_waiting = false;

    ////// Mutexes //////

    // access to task queues
    std::mutex fresh_queue_mutex, finished_queue_mutex;

    // design map access
    std::mutex designs_mutex;
  
    // reference map access
    std::mutex references_mutex;

    // notify upload thread that the finished queue is ready for cleanup
    std::atomic_bool cleanup_ready;
    std::mutex cleanup_ready_mutex;
    std::condition_variable cleanup_ready_condition;

    // inform the worker threads that there is data in the fresh task queue
    std::mutex fresh_queue_empty_mutex;
    std::condition_variable fresh_queue_empty_condition;

    // inform the upload thread that there is data in the fresh task queue
    std::mutex finished_queue_empty_mutex;
    std::condition_variable finished_queue_empty_condition;

    // inform the download thread that data was consumed
    std::mutex fresh_queue_full_mutex;
    std::condition_variable fresh_queue_full_condition;

    // inform the main thread that the program is ending
    std::mutex download_halt_mutex;
    std::condition_variable download_halt_condition;
};

#endif