/*
  * Copyright (c) 2012 Michael Niedermayer <michaelni@gmx.at>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 

 #include <stdatomic.h>
 

 #include "frame_thread_encoder.h"
 
 #include "libavutil/fifo.h"
 #include "libavutil/avassert.h"
 #include "libavutil/imgutils.h"

 #include "libavutil/opt.h"

 #include "libavutil/thread.h"

 #include "avcodec.h"
 #include "internal.h"
 #include "thread.h"
 
 #define MAX_THREADS 64
 #define BUFFER_SIZE (2*MAX_THREADS)
 
 typedef struct{
     void *indata;
     void *outdata;
     int64_t return_code;
     unsigned index;
 } Task;
 
 typedef struct{
     AVCodecContext *parent_avctx;
     pthread_mutex_t buffer_mutex;
 
     AVFifoBuffer *task_fifo;
     pthread_mutex_t task_fifo_mutex;
     pthread_cond_t task_fifo_cond;
 
     Task finished_tasks[BUFFER_SIZE];
     pthread_mutex_t finished_task_mutex;
     pthread_cond_t finished_task_cond;
 
     unsigned task_index;
     unsigned finished_task_index;
 
     pthread_t worker[MAX_THREADS];

     atomic_int exit;

 } ThreadContext;
 
 static void * attribute_align_arg worker(void *v){
     AVCodecContext *avctx = v;
     ThreadContext *c = avctx->internal->frame_thread_encoder;
     AVPacket *pkt = NULL;
 

     while (!atomic_load(&c->exit)) {

         int got_packet, ret;
         AVFrame *frame;
         Task task;
 

         if(!pkt) pkt = av_packet_alloc();

         if(!pkt) continue;
         av_init_packet(pkt);
 
         pthread_mutex_lock(&c->task_fifo_mutex);

         while (av_fifo_size(c->task_fifo) <= 0 || atomic_load(&c->exit)) {
             if (atomic_load(&c->exit)) {

                 pthread_mutex_unlock(&c->task_fifo_mutex);
                 goto end;
             }
             pthread_cond_wait(&c->task_fifo_cond, &c->task_fifo_mutex);
         }
         av_fifo_generic_read(c->task_fifo, &task, sizeof(task), NULL);
         pthread_mutex_unlock(&c->task_fifo_mutex);
         frame = task.indata;
 
         ret = avcodec_encode_video2(avctx, pkt, frame, &got_packet);
         pthread_mutex_lock(&c->buffer_mutex);

         av_frame_unref(frame);

         pthread_mutex_unlock(&c->buffer_mutex);

         av_frame_free(&frame);

         if(got_packet) {

             int ret2 = av_dup_packet(pkt);
             if (ret >= 0 && ret2 < 0)
                 ret = ret2;

         } else {

             pkt->data = NULL;
             pkt->size = 0;

         }

         pthread_mutex_lock(&c->finished_task_mutex);
         c->finished_tasks[task.index].outdata = pkt; pkt = NULL;
         c->finished_tasks[task.index].return_code = ret;
         pthread_cond_signal(&c->finished_task_cond);
         pthread_mutex_unlock(&c->finished_task_mutex);
     }
 end:
     av_free(pkt);
     pthread_mutex_lock(&c->buffer_mutex);
     avcodec_close(avctx);
     pthread_mutex_unlock(&c->buffer_mutex);
     av_freep(&avctx);
     return NULL;
 }
 

 int ff_frame_thread_encoder_init(AVCodecContext *avctx, AVDictionary *options){

     int i=0;
     ThreadContext *c;
 
 
     if(   !(avctx->thread_type & FF_THREAD_FRAME)

        || !(avctx->codec->capabilities & AV_CODEC_CAP_INTRA_ONLY))

         return 0;
 

     if(   !avctx->thread_count
        && avctx->codec_id == AV_CODEC_ID_MJPEG

        && !(avctx->flags & AV_CODEC_FLAG_QSCALE)) {

         av_log(avctx, AV_LOG_DEBUG,
                "Forcing thread count to 1 for MJPEG encoding, use -thread_type slice "
                "or a constant quantizer if you want to use multiple cpu cores\n");
         avctx->thread_count = 1;
     }

     if(   avctx->thread_count > 1
        && avctx->codec_id == AV_CODEC_ID_MJPEG

        && !(avctx->flags & AV_CODEC_FLAG_QSCALE))

         av_log(avctx, AV_LOG_WARNING,
                "MJPEG CBR encoding works badly with frame multi-threading, consider "
                "using -threads 1, -thread_type slice or a constant quantizer.\n");

 
     if (avctx->codec_id == AV_CODEC_ID_HUFFYUV ||
         avctx->codec_id == AV_CODEC_ID_FFVHUFF) {

         int warn = 0;

         int context_model = 0;
         AVDictionaryEntry *con = av_dict_get(options, "context", NULL, AV_DICT_MATCH_CASE);
 
         if (con && con->value)
             context_model = atoi(con->value);
 

         if (avctx->flags & AV_CODEC_FLAG_PASS1)

             warn = 1;

         else if(context_model > 0) {

             AVDictionaryEntry *t = av_dict_get(options, "non_deterministic",
                                                NULL, AV_DICT_MATCH_CASE);
             warn = !t || !t->value || !atoi(t->value) ? 1 : 0;
         }

         // huffyuv does not support these with multiple frame threads currently

         if (warn) {

             av_log(avctx, AV_LOG_WARNING,
                "Forcing thread count to 1 for huffyuv encoding with first pass or context 1\n");

             avctx->thread_count = 1;
         }
     }
 

     if(!avctx->thread_count) {

         avctx->thread_count = av_cpu_count();

         avctx->thread_count = FFMIN(avctx->thread_count, MAX_THREADS);
     }
 
     if(avctx->thread_count <= 1)
         return 0;
 
     if(avctx->thread_count > MAX_THREADS)
         return AVERROR(EINVAL);
 
     av_assert0(!avctx->internal->frame_thread_encoder);
     c = avctx->internal->frame_thread_encoder = av_mallocz(sizeof(ThreadContext));
     if(!c)
         return AVERROR(ENOMEM);
 
     c->parent_avctx = avctx;
 

     c->task_fifo = av_fifo_alloc_array(BUFFER_SIZE, sizeof(Task));

     if(!c->task_fifo)
         goto fail;
 
     pthread_mutex_init(&c->task_fifo_mutex, NULL);
     pthread_mutex_init(&c->finished_task_mutex, NULL);
     pthread_mutex_init(&c->buffer_mutex, NULL);
     pthread_cond_init(&c->task_fifo_cond, NULL);
     pthread_cond_init(&c->finished_task_cond, NULL);

     atomic_init(&c->exit, 0);

 
     for(i=0; i<avctx->thread_count ; i++){

         AVDictionary *tmp = NULL;

         int ret;

         void *tmpv;

         AVCodecContext *thread_avctx = avcodec_alloc_context3(avctx->codec);
         if(!thread_avctx)
             goto fail;

         tmpv = thread_avctx->priv_data;

         *thread_avctx = *avctx;

         ret = av_opt_copy(thread_avctx, avctx);

         if (ret < 0)
             goto fail;

         thread_avctx->priv_data = tmpv;

         thread_avctx->internal = NULL;

         if (avctx->codec->priv_class) {
             int ret = av_opt_copy(thread_avctx->priv_data, avctx->priv_data);
             if (ret < 0)
                 goto fail;
         } else
             memcpy(thread_avctx->priv_data, avctx->priv_data, avctx->codec->priv_data_size);

         thread_avctx->thread_count = 1;
         thread_avctx->active_thread_type &= ~FF_THREAD_FRAME;
 

         av_dict_copy(&tmp, options, 0);
         av_dict_set(&tmp, "threads", "1", 0);
         if(avcodec_open2(thread_avctx, avctx->codec, &tmp) < 0) {
             av_dict_free(&tmp);

             goto fail;
         }

         av_dict_free(&tmp);

         av_assert0(!thread_avctx->internal->frame_thread_encoder);
         thread_avctx->internal->frame_thread_encoder = c;
         if(pthread_create(&c->worker[i], NULL, worker, thread_avctx)) {
             goto fail;
         }
     }
 
     avctx->active_thread_type = FF_THREAD_FRAME;
 
     return 0;
 fail:
     avctx->thread_count = i;
     av_log(avctx, AV_LOG_ERROR, "ff_frame_thread_encoder_init failed\n");
     ff_frame_thread_encoder_free(avctx);
     return -1;
 }
 
 void ff_frame_thread_encoder_free(AVCodecContext *avctx){
     int i;
     ThreadContext *c= avctx->internal->frame_thread_encoder;
 
     pthread_mutex_lock(&c->task_fifo_mutex);

     atomic_store(&c->exit, 1);

     pthread_cond_broadcast(&c->task_fifo_cond);
     pthread_mutex_unlock(&c->task_fifo_mutex);
 
     for (i=0; i<avctx->thread_count; i++) {
          pthread_join(c->worker[i], NULL);
     }
 
     pthread_mutex_destroy(&c->task_fifo_mutex);
     pthread_mutex_destroy(&c->finished_task_mutex);
     pthread_mutex_destroy(&c->buffer_mutex);
     pthread_cond_destroy(&c->task_fifo_cond);
     pthread_cond_destroy(&c->finished_task_cond);

     av_fifo_freep(&c->task_fifo);

     av_freep(&avctx->internal->frame_thread_encoder);
 }
 
 int ff_thread_video_encode_frame(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *frame, int *got_packet_ptr){
     ThreadContext *c = avctx->internal->frame_thread_encoder;
     Task task;
     int ret;
 
     av_assert1(!*got_packet_ptr);
 
     if(frame){

         AVFrame *new = av_frame_alloc();
         if(!new)
             return AVERROR(ENOMEM);
         ret = av_frame_ref(new, frame);
         if(ret < 0) {
             av_frame_free(&new);
             return ret;

         }
 
         task.index = c->task_index;

         task.indata = (void*)new;

         pthread_mutex_lock(&c->task_fifo_mutex);
         av_fifo_generic_write(c->task_fifo, &task, sizeof(task), NULL);
         pthread_cond_signal(&c->task_fifo_cond);
         pthread_mutex_unlock(&c->task_fifo_mutex);
 
         c->task_index = (c->task_index+1) % BUFFER_SIZE;
     }
 
     pthread_mutex_lock(&c->finished_task_mutex);

     if (c->task_index == c->finished_task_index ||
         (frame && !c->finished_tasks[c->finished_task_index].outdata &&
          (c->task_index - c->finished_task_index) % BUFFER_SIZE <= avctx->thread_count)) {
             pthread_mutex_unlock(&c->finished_task_mutex);
             return 0;
         }
 

     while (!c->finished_tasks[c->finished_task_index].outdata) {
         pthread_cond_wait(&c->finished_task_cond, &c->finished_task_mutex);
     }
     task = c->finished_tasks[c->finished_task_index];
     *pkt = *(AVPacket*)(task.outdata);

     if(pkt->data)
         *got_packet_ptr = 1;

     av_freep(&c->finished_tasks[c->finished_task_index].outdata);

     c->finished_task_index = (c->finished_task_index+1) % BUFFER_SIZE;
     pthread_mutex_unlock(&c->finished_task_mutex);
 
     return task.return_code;
 }