#ifndef THREADQUEUE_H_
#define THREADQUEUE_H_
/*****************************************************************************
 * This file is part of Kvazaar HEVC encoder.
 *
 * Copyright (C) 2013-2014 Tampere University of Technology and others (see
 * COPYING file).
 *
 * Kvazaar is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * Kvazaar 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 Kvazaar.  If not, see <http://www.gnu.org/licenses/>.
 ****************************************************************************/

#include <pthread.h>
#ifdef _DEBUG
#include <time.h>
#endif

typedef enum {
  THREADQUEUE_JOB_STATE_QUEUED = 0,
  THREADQUEUE_JOB_STATE_RUNNING = 1,
  THREADQUEUE_JOB_STATE_DONE = 2
} threadqueue_job_state;

typedef struct threadqueue_job {
  pthread_mutex_t lock;
  
  threadqueue_job_state state;
  
  unsigned int ndepends; //Number of job on which this job depends
  
  struct threadqueue_job **rdepends; //array of pointer to jobs that depend on this one. They have to exist when the thread finishes, because they cannot be run before.
  unsigned int rdepends_count; //number of rdepends
  unsigned int rdepends_size; //allocated size of rdepends
  
  //Job function and state to use
  void (*fptr)(void *arg);
  void *arg;
  
#ifdef _DEBUG
  const char* debug_description;
  
  int debug_worker_id;
  
  struct timespec debug_clock_enqueue;
  struct timespec debug_clock_start;
  struct timespec debug_clock_stop;
  struct timespec debug_clock_dequeue;
#endif
} threadqueue_job;


  

typedef struct {
  pthread_mutex_t lock;
  pthread_cond_t cond;
  pthread_cond_t cb_cond;
  
  pthread_t *threads;
  int threads_count;
  int threads_running;

  int stop; //=>1: threads should stop asap
  
  threadqueue_job **queue;
  unsigned int queue_count;
  unsigned int queue_size;
  unsigned int queue_waiting;
  
#ifdef _DEBUG
  //Format: pointer <tab> worker id <tab> time enqueued <tab> time started <tab> time stopped <tab> time dequeued <tab> job description
  //For threads, pointer = "" and job description == "thread", time enqueued and time dequeued are equal to "-"
  //For flush, pointer = "" and job description == "FLUSH", time enqueued, time dequeued and time started are equal to "-" 
  //Each time field, except the first one in the line be expressed in a relative way, by prepending the number of seconds by +.
  //Dependencies: pointer -> pointer

  FILE *debug_log;
  
  struct timespec *debug_clock_thread_start;
  struct timespec *debug_clock_thread_end;
#endif
} threadqueue_queue;

//Init a threadqueue
int threadqueue_init(threadqueue_queue * threadqueue, int thread_count);

//Add a job to the queue, and returs a threadqueue_job handle. If wait == 1, one has to run threadqueue_job_unwait_job in order to have it run
threadqueue_job * threadqueue_submit(threadqueue_queue * threadqueue, void (*fptr)(void *arg), void *arg, int wait, const char* debug_description);

int threadqueue_job_unwait_job(threadqueue_queue * threadqueue, threadqueue_job *job);

//Add a dependency between two jobs.
int threadqueue_job_dep_add(threadqueue_job *job, threadqueue_job *depends_on);

//Blocking call until the queue is empty. Previously set threadqueue_job handles should not be used anymore
int threadqueue_flush(threadqueue_queue * threadqueue);

//Free ressources in a threadqueue
int threadqueue_finalize(threadqueue_queue * threadqueue);

#ifdef _DEBUG
int threadqueue_log(threadqueue_queue * threadqueue, const struct timespec *start, const struct timespec *stop, const char* debug_description);

//This macro HAS TO BE at the beginning of a block
#define PERFORMANCE_MEASURE_START() struct timespec start, stop; clock_gettime(CLOCK_MONOTONIC, &start)
#define PERFORMANCE_MEASURE_END(threadqueue, str, ...) do {clock_gettime(CLOCK_MONOTONIC, &stop); {char job_description[256]; sprintf(job_description, (str), __VA_ARGS__); threadqueue_log((threadqueue), &start, &stop, job_description); }} while (0)
#else
#define PERFORMANCE_MEASURE_START() do {} while (0)
#define PERFORMANCE_MEASURE_END(threadqueue, str, ...) do {} while (0)
#endif

/* Constraints: 
 * 
 * - Always first lock threadqueue, than a job inside it
 * - When job A depends on job B, always lock first job B and then job A
 * 
 * */

#endif //THREADQUEUE_H_