#ifndef TIMERQUEUE_H
#define TIMERQUEUE_H

#pragma once

#include "config.h"

#ifdef __cplusplus
extern "C" {
#endif

typedef struct timer_entry timer_entry;
typedef struct timer_queue_s timer_queue_t;

typedef void (*timerqueue_callback)(timer_queue_t *q, timer_entry *timer, int err);

struct timer_entry 
{
	/** 
     * User data to be associated with this entry. 
     * Applications normally will put the instance of object that
     * owns the timer entry in this field.
     */
    void *user_data;

    /** 
     * Arbitrary ID assigned by the user/owner of this entry. 
     * Applications can use this ID to distinguish multiple
     * timer entries that share the same callback and user_data.
     */
    int id;

    /** 
     * Callback to be called when the timer expires. 
     */
    timerqueue_callback cb;

	/**
	 * Internal usage only, user dont use it
	 */
	void *_private[4];
};

/** timer queue implemented by sorted list */
TOOLKIT_API int timer_sortedlist_create(timer_queue_t **p_q);

/** timer queue implemented by heap */
TOOLKIT_API int timer_heap_create(timer_queue_t **p_q);

/** timer queue implemented by wheel */
TOOLKIT_API int timer_wheel_create(int num_wheel, int wheel_time, timer_queue_t **p_q);

/**
 * destroy timer queue
 */
TOOLKIT_API void timer_queue_destroy(timer_queue_t *q);

/**
 * set timer
 * @param delay delay time from now, in milliseconds, zero means due immediately
 */
TOOLKIT_API int timer_queue_schedule(timer_queue_t *q, timer_entry *entry, unsigned int delay);

/**
 * cancel timer
 */
TOOLKIT_API int timer_queue_cancel(timer_queue_t *q, timer_entry *entry, int cancel);

/**
 * get timer count in the heap
 */
TOOLKIT_API int timer_queue_get_count(timer_queue_t *q);

/**
 * poll the timer heap
 * @param next_delay next delay in milliseconds, can be null, if next_delay == -1, no timer in the heap
 * @return the number of triggered timers
 */
TOOLKIT_API int timer_queue_poll(timer_queue_t *q, int *next_delay);

/**
 * poll only one timer in the time heap
 * @param p_entry pointer to the timer which is expired, if not will be NULL
 * @param next_delay next delay in milliseconds, can be null, if next_delay == -1, no timer in the heap
 * @return the number of triggered timers
 */
TOOLKIT_API int timer_queue_poll_one(timer_queue_t *q, timer_entry **p_entry, int *next_delay);

#ifdef __cplusplus
} // extern "C" {
#endif

#endif // TIMERQUEUE_H