#ifndef __EV_LOOP__
#define __EV_LOOP__

#include <pthread.h>

#define MAX_PRIORITY_LEVEL 4

typedef struct task_ task_t;
typedef struct event_loop_ event_loop_t;


typedef enum EL_RES_ {
    EL_CONTINUE,
    EL_FINISH
} EL_RES_T;

typedef enum TASK_PRIORITY {
    TASK_PRIORITY_HIGH,
    TASK_PRIORITY_MEDIUM,
    TASK_PRIORITY_LOW,
    TASK_PRIORITY_MAX
}TASK_PRIORITY_T;

typedef  EL_RES_T (*event_cbk)(void*);


struct task_ {

    event_cbk cbk;
    void* arg;
    struct task_* left, * right;
    TASK_PRIORITY_T priority;
};

typedef enum {

    EV_LOOP_IDLE,
    EV_LOOP_BUSY
} EV_LOOP_STATE;

struct event_loop_ {

    /* head to the start of the task array */
    struct task_* task_array_head[MAX_PRIORITY_LEVEL];
    /* Mutex to enforce Mutual exclusion enqueue/Deque
     * Operation in task array. Also used to update event loop
     * attributes in mutual exclusive way
     */
    pthread_mutex_t ev_loop_mutex;
    /* State of event loop */
    EV_LOOP_STATE ev_loop_state;
    /* CV to suspened event loop thread */
    pthread_cond_t ev_loop_cv;
    /*  Event loop thread */
    pthread_t* thread;
    /* Current task which event loop thread is executing.
     * NULL if event loop is resting in peace*/
    struct task_* current_task;
};

void
event_loop_init(event_loop_t* el);

void
event_loop_run(event_loop_t* el);

task_t*
task_create_new_job(event_loop_t* el, event_cbk cbk, void* arg, TASK_PRIORITY_T priority);

void
task_cancel_job(event_loop_t* el, task_t* task);



#endif