/* BSD-2-Clause license
 * 
 * Copyright (c) 2018-2023 NST <www.newinfosec.ru>, sss <sss at dark-alexandr dot net>. 
 * 
 */

#pragma once

#include <stdint.h>
#include <ev.h>

struct wrdp_thpool_s;
typedef struct wrdp_thpool_s wrdp_thpool;

struct wrdp_thpool_thread_s;
typedef struct wrdp_thpool_thread_s wrdp_thpool_thread;

struct wrdp_thpool_task_s;
typedef struct wrdp_thpool_task_s wrdp_thpool_task;

/* initialize thread pool */

/* function called in each thread to do additional initialization
 * of user_pool_data
void (*custom_thread_init) (void *user_pool_data);
*/

/* function called in each thread to do additional cleanup of
 * user_pool_data
void (*custom_thread_deinit) (void *user_pool_data);
*/

/* function called in wrdp_thpool_create to do additional initialization
 * of user_pool_data
void (*custom_pool_create) (void *user_pool_data);
*/

/* function called in wrdp_thpool_destroy to do additional cleanup of
 * user_pool_data
void (*custom_pool_destroy) (void *user_pool_data);
*/
/* function called on incomming mesdage with "void *user_data" directed to
 * pool
void (*pool_message_handler) (void *user_data);
 */

/* function called on incomming message with "void *user_data" directed to
 * thrad
void (*thread_message_handler) (void *user_data);
 */

/* struct ev_loop* loop
 * it's possible to use specified ev_loop instead of EV_DEFAULT
 */

wrdp_thpool *wrdp_thpool_create(uint16_t thread_count,
    uint64_t max_tasks_per_thread,
    void (*custom_thread_init)(void *user_pool_data, wrdp_thpool_thread *t),
    void (*custom_thread_deinit)(void *user_pool_data, wrdp_thpool_thread *t),
    void (*custom_pool_create)(void *user_pool_data),
    void (*custom_pool_destroy)(void *user_pool_data),
    void (*pool_message_handler)(void *user_data),
    void (*thread_message_handler)(void *user_data), struct ev_loop *loop,
    void *user_pool_data);

/* deinitialize thread pool */
void wrdp_thpool_destroy(wrdp_thpool *pool);

/*
 * Add task to thread pool.
 * task will be added to thread with minimal tasks count
 * Not thread safe.
 * Must be called from thread which created thread pool only.
 *
 * pool: fully initialized thread pool
 * run_task: task entry point callback
 * must not block but set libev watcher instead
 *
 * userdata: user specified data pointer
 */
bool wrdp_thread_pool_add_task(wrdp_thpool *pool,
    void (*run_task)(wrdp_thpool_task *task, void *userdata),
    void (*task_init_cb)(wrdp_thpool_task *task, void *userdata),
    void *userdata);

/*
 * Add task to thread pool to specified thread.
 * task will be added to specified thread
 * Not thread safe.
 * Must be called from thread which created thread pool only.
 *
 * pool: fully initialized thread pool
 *
 * thread_id: id of the thread to run task in
 *
 * run_task: task entry point callback
 * must not block but set libev watcher instead
 *
 * userdata: user specified data pointer
 */
bool wrdp_thread_pool_add_task_to_thread(wrdp_thpool *pool,
    void (*run_task)(wrdp_thpool_task *task, void *userdata),
    uint32_t thread_id,
    void (*task_init_cb)(wrdp_thpool_task *task, void *userdata),
    void *userdata);

/*
 * Move task to specified thread.
 * task will be moved to specified thread
 *
 * (technically new task in specified thread will
 * be created, and current task will be deleted
 * preserving task internal state)
 *
 * pool: fully initialized thread pool
 *
 * thread_id: id of the thread to run task in
 *
 * run_task: task entry point callback
 * must not block but set libev watcher instead
 *
 * stop_task: callback function used to prepare task for ruining in new thread
 *
 * userdata: user specified data pointer
 */
bool wrdp_thread_pool_move_task_to_thread(wrdp_thpool *pool,
    void (*run_task)(wrdp_thpool_task *task, void *userdata),
    void (*stop_task)(wrdp_thpool_task *current_task, void *userdata),
    uint32_t thread_id,
    void (*task_init_cb)(wrdp_thpool_task *task, void *userdata),
    wrdp_thpool_task *current_task, void *userdata);

/*
 * it is possible to send message with "void *user_data" to specified thread,
 * or to pool main thread
 * NOTE: custom message handler function must also be set during pool creation
 */

bool wrdp_thpool_send_msg_to_thread(
    wrdp_thpool *pool, uint32_t thread_id, void *user_data);

bool wrdp_thpool_send_msg_to_pool(wrdp_thpool *pool, void *user_data);

/*
 * Destroy runing task.
 * Custom destroy is function ptr "void(*callable)(wrdp_thpool_task* task)".
 */

void wrdp_thread_pool_destroy_task(
    wrdp_thpool_task *task, void (*on_task_destroy)(wrdp_thpool_task *task));