/* SPDX-FileCopyrightText: 2001-2002 NaN Holding BV. All rights reserved.
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup spseq
 */

#include "DNA_sequence_types.h"
#include "DNA_sound_types.h"

#include "BLI_listbase.h"
#include "BLI_task.h"
#include "BLI_threads.h"

#include "BKE_context.hh"
#include "BKE_global.hh"
#include "BKE_sound.h"

#include "WM_api.hh"
#include "WM_types.hh"

#include "ED_screen.hh"

#include "MEM_guardedalloc.h"

#include "sequencer_intern.hh"

struct PreviewJob {
  ListBase previews;
  ThreadMutex *mutex;
  Scene *scene;
  int total;
  int processed;
  ThreadCondition preview_suspend_cond;
  bool running;
};

struct PreviewJobAudio {
  PreviewJobAudio *next, *prev;
  Main *bmain;
  bSound *sound;
  int lr; /* Sample left or right. */
  int startframe;
  bool waveform; /* Reload sound or waveform. */
};

struct ReadSoundWaveformTask {
  PreviewJob *wm_job;
  PreviewJobAudio *preview_job_audio;
  bool *stop;
};

static void free_preview_job(void *data)
{
  PreviewJob *pj = static_cast<PreviewJob *>(data);

  BLI_mutex_free(pj->mutex);
  BLI_freelistN(&pj->previews);
  MEM_freeN(pj);
}

static void clear_sound_waveform_loading_tag(bSound *sound)
{
  SpinLock *spinlock = static_cast<SpinLock *>(sound->spinlock);
  BLI_spin_lock(spinlock);
  sound->tags &= ~SOUND_TAGS_WAVEFORM_LOADING;
  BLI_spin_unlock(spinlock);
}

static void free_read_sound_waveform_task(TaskPool *__restrict task_pool, void *data)
{
  UNUSED_VARS(task_pool);

  ReadSoundWaveformTask *task = static_cast<ReadSoundWaveformTask *>(data);

  /* The job audio has already been removed from the list, now we just need to free it. */
  MEM_freeN(task->preview_job_audio);

  BLI_mutex_lock(task->wm_job->mutex);
  task->wm_job->processed++;
  BLI_mutex_unlock(task->wm_job->mutex);

  BLI_condition_notify_one(&task->wm_job->preview_suspend_cond);

  MEM_freeN(task);
}

static void execute_read_sound_waveform_task(TaskPool *__restrict task_pool, void *task_data)
{
  ReadSoundWaveformTask *task = static_cast<ReadSoundWaveformTask *>(task_data);

  if (BLI_task_pool_current_canceled(task_pool)) {
    clear_sound_waveform_loading_tag(task->preview_job_audio->sound);
    return;
  }

  PreviewJobAudio *audio_job = task->preview_job_audio;
  BKE_sound_read_waveform(audio_job->bmain, audio_job->sound, task->stop);
}

static void push_preview_job_audio_task(TaskPool *__restrict task_pool,
                                        PreviewJob *pj,
                                        PreviewJobAudio *previewjb,
                                        bool *stop)
{
  ReadSoundWaveformTask *task = MEM_cnew<ReadSoundWaveformTask>("read sound waveform task");
  task->wm_job = pj;
  task->preview_job_audio = previewjb;
  task->stop = stop;

  BLI_task_pool_push(
      task_pool, execute_read_sound_waveform_task, task, true, free_read_sound_waveform_task);
}

/* Only this runs inside thread. */
static void preview_startjob(void *data, wmJobWorkerStatus *worker_status)
{
  TaskPool *task_pool = BLI_task_pool_create(nullptr, TASK_PRIORITY_LOW);
  PreviewJob *pj = static_cast<PreviewJob *>(data);

  while (true) {
    /* Wait until there's either a new audio job to process or one of the previously submitted jobs
     * is done. */
    BLI_mutex_lock(pj->mutex);

    while (BLI_listbase_is_empty(&pj->previews) && pj->processed != pj->total) {

      float current_progress = (pj->total > 0) ? float(pj->processed) / float(pj->total) : 1.0f;

      if (current_progress != worker_status->progress) {
        worker_status->progress = current_progress;
        worker_status->do_update = true;
      }

      BLI_condition_wait(&pj->preview_suspend_cond, pj->mutex);
    }

    if (pj->processed == pj->total) {
      pj->running = false;
      BLI_mutex_unlock(pj->mutex);
      break;
    }

    if (worker_status->stop || G.is_break) {
      BLI_task_pool_cancel(task_pool);

      LISTBASE_FOREACH (PreviewJobAudio *, previewjb, &pj->previews) {
        clear_sound_waveform_loading_tag(previewjb->sound);
      }

      BLI_freelistN(&pj->previews);
      pj->processed = 0;
      pj->total = 0;
      pj->running = false;

      BLI_mutex_unlock(pj->mutex);
      break;
    }

    LISTBASE_FOREACH_MUTABLE (PreviewJobAudio *, previewjb, &pj->previews) {
      push_preview_job_audio_task(task_pool, pj, previewjb, &worker_status->stop);

      BLI_remlink(&pj->previews, previewjb);
    }

    BLI_mutex_unlock(pj->mutex);
  }

  BLI_task_pool_work_and_wait(task_pool);
  BLI_task_pool_free(task_pool);
}

static void preview_endjob(void *data)
{
  PreviewJob *pj = static_cast<PreviewJob *>(data);

  WM_main_add_notifier(NC_SCENE | ND_SEQUENCER, pj->scene);
}

void sequencer_preview_add_sound(const bContext *C, Sequence *seq)
{
  wmJob *wm_job;
  PreviewJob *pj;
  ScrArea *area = CTX_wm_area(C);

  wm_job = WM_jobs_get(CTX_wm_manager(C),
                       CTX_wm_window(C),
                       CTX_data_scene(C),
                       "Strip Previews",
                       WM_JOB_PROGRESS,
                       WM_JOB_TYPE_SEQ_BUILD_PREVIEW);

  /* Get the preview job if it exists. */
  pj = static_cast<PreviewJob *>(WM_jobs_customdata_get(wm_job));

  if (pj) {
    BLI_mutex_lock(pj->mutex);

    /* If the job exists but is not running, bail and try again on the next draw call. */
    if (!pj->running) {
      BLI_mutex_unlock(pj->mutex);

      /* Clear the sound loading tag to that it can be reattempted. */
      clear_sound_waveform_loading_tag(seq->sound);
      WM_event_add_notifier(C, NC_SCENE | ND_SPACE_SEQUENCER, CTX_data_scene(C));
      return;
    }
  }
  else { /* There's no existing preview job. */
    pj = MEM_cnew<PreviewJob>("preview rebuild job");

    pj->mutex = BLI_mutex_alloc();
    BLI_condition_init(&pj->preview_suspend_cond);
    pj->scene = CTX_data_scene(C);
    pj->running = true;
    BLI_mutex_lock(pj->mutex);

    WM_jobs_customdata_set(wm_job, pj, free_preview_job);
    WM_jobs_timer(wm_job, 0.1, NC_SCENE | ND_SEQUENCER, NC_SCENE | ND_SEQUENCER);
    WM_jobs_callbacks(wm_job, preview_startjob, nullptr, nullptr, preview_endjob);
  }

  PreviewJobAudio *audiojob = MEM_cnew<PreviewJobAudio>("preview_audio");
  audiojob->bmain = CTX_data_main(C);
  audiojob->sound = seq->sound;

  BLI_addtail(&pj->previews, audiojob);
  pj->total++;
  BLI_mutex_unlock(pj->mutex);

  BLI_condition_notify_one(&pj->preview_suspend_cond);

  if (!WM_jobs_is_running(wm_job)) {
    G.is_break = false;
    WM_jobs_start(CTX_wm_manager(C), wm_job);
  }

  ED_area_tag_redraw(area);
}