#ifndef UCORE_TIMERS_H_
#define UCORE_TIMERS_H_

#include <stddef.h>
#include <sys/queue.h>
#include <sys/time.h>
#include "ucore_rbtree.h"


struct UCTimer;
struct UCTimers;

//timer states
enum {
    //not running
    UC_TIMER_INACTIVE   = 0,
    //running
    UC_TIMER_ACTIVE     = 1,
    //running and pending to be fired in this run of uc_timers_run
    UC_TIMER_PENDING    = 2
};

typedef void (*uc_timer_cb)(struct UCTimers *timers, struct UCTimer *timer);
struct UCTimer {
    //Internal members 
    RBNode rb_node; //the RBNode will hold a data pointer to the
                    //the UCTimer it's a member of. We might get rid of that member, and use CONTAINER_OF
                    //to find the UCTimer from a RBNode
    //
    //absolute time when the timer should be fired
    struct timeval timeout;
    size_t seq; //needed to keep timeout unique
                //as the rbtree can only handle unique values
    unsigned char state;
    TAILQ_ENTRY(UCTimer) ready_entry; //entry in ready_list in UCTimers

    //External members

    //callback function
    uc_timer_cb callback;

    //user data for the callback
    void *cookie_ptr;
    int cookie_int;
    int cookie_int2;
};


struct UCTimers {
    RBTree timers;
    size_t seq; //used to generate unique timers
    TAILQ_HEAD(, UCTimer) ready_list; //pending timers to be fired while inside uc_timers_run
};


void uc_timer_remove(struct UCTimers *timers, struct UCTimer *timer);
void uc_timers_init(struct UCTimers *t);
void uc_timer_add(struct UCTimers *timers, struct UCTimer *timer, int sec, int usec);
void uc_timer_remove(struct UCTimers *timers, struct UCTimer *timer);
int uc_timers_first(const struct UCTimers *timers, struct timeval *first);
size_t uc_timer_count(const struct UCTimers *timers);
int uc_timer_running(const struct UCTimer *timer);
int uc_timers_run(struct UCTimers *timers, const struct timeval *now);

#endif