/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright 2021 Blender Foundation. All rights reserved. */

/** \file
 * \ingroup sequencer
 */

#include "SEQ_sequencer.h"
#include "sequencer.h"

#include "DNA_listBase.h"
#include "DNA_scene_types.h"
#include "DNA_sequence_types.h"

#include "SEQ_iterator.h"

#include "BLI_ghash.h"
#include "BLI_listbase.h"
#include "BLI_string.h"
#include "BLI_sys_types.h"
#include "BLI_threads.h"
#include <string.h>

#include "MEM_guardedalloc.h"

static ThreadMutex lookup_lock = BLI_MUTEX_INITIALIZER;

typedef struct SequenceLookup {
  GHash *seq_by_name;
  GHash *meta_by_seq;
  GHash *effects_by_seq;
  eSequenceLookupTag tag;
} SequenceLookup;

static void seq_sequence_lookup_init(struct SequenceLookup *lookup)
{
  lookup->seq_by_name = BLI_ghash_str_new(__func__);
  lookup->meta_by_seq = BLI_ghash_ptr_new(__func__);
  lookup->effects_by_seq = BLI_ghash_ptr_new(__func__);
  lookup->tag |= SEQ_LOOKUP_TAG_INVALID;
}

static void seq_sequence_lookup_append_effect(Sequence *input,
                                              Sequence *effect,
                                              struct SequenceLookup *lookup)
{
  if (input == NULL) {
    return;
  }

  SeqCollection *effects = BLI_ghash_lookup(lookup->effects_by_seq, input);
  if (effects == NULL) {
    effects = SEQ_collection_create(__func__);
    BLI_ghash_insert(lookup->effects_by_seq, input, effects);
  }

  SEQ_collection_append_strip(effect, effects);
}

static void seq_sequence_lookup_build_effect(Sequence *seq, struct SequenceLookup *lookup)
{
  if ((seq->type & SEQ_TYPE_EFFECT) == 0) {
    return;
  }

  seq_sequence_lookup_append_effect(seq->seq1, seq, lookup);
  seq_sequence_lookup_append_effect(seq->seq2, seq, lookup);
}

static void seq_sequence_lookup_build_from_seqbase(Sequence *parent_meta,
                                                   const ListBase *seqbase,
                                                   struct SequenceLookup *lookup)
{
  LISTBASE_FOREACH (Sequence *, seq, seqbase) {
    BLI_ghash_insert(lookup->seq_by_name, seq->name + 2, seq);
    BLI_ghash_insert(lookup->meta_by_seq, seq, parent_meta);
    seq_sequence_lookup_build_effect(seq, lookup);

    if (seq->type == SEQ_TYPE_META) {
      seq_sequence_lookup_build_from_seqbase(seq, &seq->seqbase, lookup);
    }
  }
}

static void seq_sequence_lookup_build(const struct Scene *scene, struct SequenceLookup *lookup)
{
  Editing *ed = SEQ_editing_get(scene);
  seq_sequence_lookup_build_from_seqbase(NULL, &ed->seqbase, lookup);
  lookup->tag &= ~SEQ_LOOKUP_TAG_INVALID;
}

static SequenceLookup *seq_sequence_lookup_new(void)
{
  SequenceLookup *lookup = MEM_callocN(sizeof(SequenceLookup), __func__);
  seq_sequence_lookup_init(lookup);
  return lookup;
}

static void seq_sequence_lookup_free(struct SequenceLookup **lookup)
{
  if (*lookup == NULL) {
    return;
  }

  BLI_ghash_free((*lookup)->seq_by_name, NULL, NULL);
  BLI_ghash_free((*lookup)->meta_by_seq, NULL, NULL);
  BLI_ghash_free((*lookup)->effects_by_seq, NULL, SEQ_collection_free_void_p);
  (*lookup)->seq_by_name = NULL;
  (*lookup)->meta_by_seq = NULL;
  (*lookup)->effects_by_seq = NULL;
  MEM_freeN(*lookup);
  *lookup = NULL;
}

static void seq_sequence_lookup_rebuild(const struct Scene *scene, struct SequenceLookup **lookup)
{
  seq_sequence_lookup_free(lookup);
  *lookup = seq_sequence_lookup_new();
  seq_sequence_lookup_build(scene, *lookup);
}

static bool seq_sequence_lookup_is_valid(const struct SequenceLookup *lookup)
{
  return (lookup->tag & SEQ_LOOKUP_TAG_INVALID) == 0;
}

static void seq_sequence_lookup_update_if_needed(const struct Scene *scene,
                                                 struct SequenceLookup **lookup)
{
  if (!scene->ed) {
    return;
  }
  if (*lookup && seq_sequence_lookup_is_valid(*lookup)) {
    return;
  }

  seq_sequence_lookup_rebuild(scene, lookup);
}

void SEQ_sequence_lookup_free(const Scene *scene)
{
  BLI_assert(scene->ed);
  BLI_mutex_lock(&lookup_lock);
  SequenceLookup *lookup = scene->ed->runtime.sequence_lookup;
  seq_sequence_lookup_free(&lookup);
  BLI_mutex_unlock(&lookup_lock);
}

Sequence *SEQ_sequence_lookup_seq_by_name(const Scene *scene, const char *key)
{
  BLI_assert(scene->ed);
  BLI_mutex_lock(&lookup_lock);
  seq_sequence_lookup_update_if_needed(scene, &scene->ed->runtime.sequence_lookup);
  SequenceLookup *lookup = scene->ed->runtime.sequence_lookup;
  Sequence *seq = BLI_ghash_lookup(lookup->seq_by_name, key);
  BLI_mutex_unlock(&lookup_lock);
  return seq;
}

Sequence *seq_sequence_lookup_meta_by_seq(const Scene *scene, const Sequence *key)
{
  BLI_assert(scene->ed);
  BLI_mutex_lock(&lookup_lock);
  seq_sequence_lookup_update_if_needed(scene, &scene->ed->runtime.sequence_lookup);
  SequenceLookup *lookup = scene->ed->runtime.sequence_lookup;
  Sequence *seq = BLI_ghash_lookup(lookup->meta_by_seq, key);
  BLI_mutex_unlock(&lookup_lock);
  return seq;
}

SeqCollection *seq_sequence_lookup_effects_by_seq(const Scene *scene, const Sequence *key)
{
  BLI_assert(scene->ed);
  BLI_mutex_lock(&lookup_lock);
  seq_sequence_lookup_update_if_needed(scene, &scene->ed->runtime.sequence_lookup);
  SequenceLookup *lookup = scene->ed->runtime.sequence_lookup;
  SeqCollection *effects = BLI_ghash_lookup(lookup->effects_by_seq, key);
  BLI_mutex_unlock(&lookup_lock);
  return effects;
}

void SEQ_sequence_lookup_tag(const Scene *scene, eSequenceLookupTag tag)
{
  if (!scene->ed) {
    return;
  }

  BLI_mutex_lock(&lookup_lock);
  SequenceLookup *lookup = scene->ed->runtime.sequence_lookup;
  if (lookup != NULL) {
    lookup->tag |= tag;
  }
  BLI_mutex_unlock(&lookup_lock);
}