/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2013 Blender Foundation.
 * All rights reserved.
 *
 * Original Author: Joshua Leung
 * Contributor(s): Sergey Sharybin
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/depsgraph/intern/depsgraph.cc
 *  \ingroup depsgraph
 *
 * Core routines for how the Depsgraph works.
 */

#include "intern/depsgraph.h" /* own include */

#include "MEM_guardedalloc.h"

#include "BLI_utildefines.h"
#include "BLI_console.h"
#include "BLI_hash.h"
#include "BLI_ghash.h"
#include "BLI_listbase.h"

extern "C" {
#include "DNA_action_types.h"
#include "DNA_armature_types.h"
#include "DNA_constraint_types.h"
#include "DNA_key_types.h"
#include "DNA_object_types.h"
#include "DNA_sequence_types.h"

#include "RNA_access.h"

#include "BKE_scene.h"
#include "BKE_constraint.h"
#include "BKE_global.h"
}

#include <algorithm>
#include <cstring>

#include "DEG_depsgraph.h"
#include "DEG_depsgraph_debug.h"

#include "intern/depsgraph_update.h"

#include "intern/eval/deg_eval_copy_on_write.h"

#include "intern/node/deg_node.h"
#include "intern/node/deg_node_component.h"
#include "intern/node/deg_node_factory.h"
#include "intern/node/deg_node_id.h"
#include "intern/node/deg_node_operation.h"
#include "intern/node/deg_node_time.h"

#include "intern/depsgraph_physics.h"

namespace DEG {

/* TODO(sergey): Find a better place for this. */
template <typename T>
static void remove_from_vector(vector<T> *vector, const T& value)
{
	vector->erase(std::remove(vector->begin(), vector->end(), value),
	              vector->end());
}

Depsgraph::Depsgraph(Scene *scene,
                     ViewLayer *view_layer,
                     eEvaluationMode mode)
  : time_source(NULL),
    need_update(true),
    scene(scene),
    view_layer(view_layer),
    mode(mode),
    ctime(BKE_scene_frame_get(scene)),
    scene_cow(NULL),
    is_active(false),
    debug_is_evaluating(false)
{
	BLI_spin_init(&lock);
	id_hash = BLI_ghash_ptr_new("Depsgraph id hash");
	entry_tags = BLI_gset_ptr_new("Depsgraph entry_tags");
	debug_flags = G.debug;
	memset(id_type_updated, 0, sizeof(id_type_updated));
	memset(physics_relations, 0, sizeof(physics_relations));
}

Depsgraph::~Depsgraph()
{
	clear_id_nodes();
	BLI_ghash_free(id_hash, NULL, NULL);
	BLI_gset_free(entry_tags, NULL);
	if (time_source != NULL) {
		OBJECT_GUARDED_DELETE(time_source, TimeSourceNode);
	}
	BLI_spin_end(&lock);
}

/* Query Conditions from RNA ----------------------- */

static bool pointer_to_component_node_criteria(
        const PointerRNA *ptr,
        const PropertyRNA *prop,
        RNAPointerSource /*source*/,
        ID **id,
        NodeType *type,
        const char **component_name,
        OperationCode *operation_code,
        const char **operation_name,
        int *operation_name_tag)
{
	if (ptr->type == NULL) {
		return false;
	}
	/* Set default values for returns. */
	*id = (ID *)ptr->id.data;
	*component_name = "";
	*operation_code = OperationCode::OPERATION;
	*operation_name = "";
	*operation_name_tag = -1;
	/* Handling of commonly known scenarios. */
	if (ptr->type == &RNA_PoseBone) {
		bPoseChannel *pchan = (bPoseChannel *)ptr->data;
		if (prop != NULL && RNA_property_is_idprop(prop)) {
			*type = NodeType::PARAMETERS;
			*operation_code = OperationCode::ID_PROPERTY;
			*operation_name = RNA_property_identifier((PropertyRNA *)prop);
			*operation_name_tag = -1;
		}
		else {
			/* Bone - generally, we just want the bone component. */
			*type = NodeType::BONE;
			*component_name = pchan->name;
			/* But B-Bone properties should connect to the actual operation. */
			if (!ELEM(NULL, pchan->bone, prop) && pchan->bone->segments > 1 &&
			    STRPREFIX(RNA_property_identifier(prop), "bbone_"))
			{
				*operation_code = OperationCode::BONE_SEGMENTS;
			}
		}
		return true;
	}
	else if (ptr->type == &RNA_Bone) {
		Bone *bone = (Bone *)ptr->data;
		/* armature-level bone, but it ends up going to bone component anyway */
		// NOTE: the ID in this case will end up being bArmature.
		*type = NodeType::BONE;
		*component_name = bone->name;
		return true;
	}
	else if (RNA_struct_is_a(ptr->type, &RNA_Constraint)) {
		Object *object = (Object *)ptr->id.data;
		bConstraint *con = (bConstraint *)ptr->data;
		/* Check whether is object or bone constraint. */
		/* NOTE: Currently none of the area can address transform of an object
		 * at a given constraint, but for rigging one might use constraint
		 * influence to be used to drive some corrective shape keys or so. */
		if (BLI_findindex(&object->constraints, con) != -1) {
			*type = NodeType::TRANSFORM;
			*operation_code = OperationCode::TRANSFORM_LOCAL;
			return true;
		}
		else if (object->pose != NULL) {
			LISTBASE_FOREACH(bPoseChannel *, pchan, &object->pose->chanbase) {
				if (BLI_findindex(&pchan->constraints, con) != -1) {
					*type = NodeType::BONE;
					*operation_code = OperationCode::BONE_LOCAL;
					*component_name = pchan->name;
					return true;
				}
			}
		}
	}
	else if (ELEM(ptr->type, &RNA_ConstraintTarget, &RNA_ConstraintTargetBone)) {
		Object *object = (Object *)ptr->id.data;
		bConstraintTarget *tgt = (bConstraintTarget *)ptr->data;
		/* Check whether is object or bone constraint. */
		bPoseChannel *pchan = NULL;
		bConstraint *con = BKE_constraint_find_from_target(object, tgt, &pchan);
		if (con != NULL) {
			if (pchan != NULL) {
				*type = NodeType::BONE;
				*operation_code = OperationCode::BONE_LOCAL;
				*component_name = pchan->name;
			}
			else {
				*type = NodeType::TRANSFORM;
				*operation_code = OperationCode::TRANSFORM_LOCAL;
			}
			return true;
		}
	}
	else if (RNA_struct_is_a(ptr->type, &RNA_Modifier)) {
		*type = NodeType::GEOMETRY;
		return true;
	}
	else if (ptr->type == &RNA_Object) {
		/* Transforms props? */
		if (prop != NULL) {
			const char *prop_identifier = RNA_property_identifier((PropertyRNA *)prop);
			/* TODO(sergey): How to optimize this? */
			if (strstr(prop_identifier, "location") ||
			    strstr(prop_identifier, "rotation") ||
			    strstr(prop_identifier, "scale") ||
			    strstr(prop_identifier, "matrix_"))
			{
				*type = NodeType::TRANSFORM;
				return true;
			}
			else if (strstr(prop_identifier, "data")) {
				/* We access object.data, most likely a geometry.
				 * Might be a bone tho. */
				*type = NodeType::GEOMETRY;
				return true;
			}
		}
	}
	else if (ptr->type == &RNA_ShapeKey) {
		KeyBlock *key_block = (KeyBlock *)ptr->data;
		*id = (ID *)ptr->id.data;
		*type = NodeType::PARAMETERS;
		*operation_code = OperationCode::PARAMETERS_EVAL;
		*operation_name = key_block->name;
		return true;
	}
	else if (ptr->type == &RNA_Key) {
		*id = (ID *)ptr->id.data;
		*type = NodeType::GEOMETRY;
		return true;
	}
	else if (RNA_struct_is_a(ptr->type, &RNA_Sequence)) {
		Sequence *seq = (Sequence *)ptr->data;
		/* Sequencer strip */
		*type = NodeType::SEQUENCER;
		*component_name = seq->name;
		return true;
	}
	else if (RNA_struct_is_a(ptr->type, &RNA_NodeSocket)) {
		*type = NodeType::SHADING;
		return true;
	}
	else if (RNA_struct_is_a(ptr->type, &RNA_ShaderNode)) {
		*type = NodeType::SHADING;
		return true;
	}
	else if (ELEM(ptr->type, &RNA_Curve, &RNA_TextCurve)) {
		*id = (ID *)ptr->id.data;
		*type = NodeType::GEOMETRY;
		return true;
	}
	if (prop != NULL) {
		/* All unknown data effectively falls under "parameter evaluation". */
		if (RNA_property_is_idprop(prop)) {
			*type = NodeType::PARAMETERS;
			*operation_code = OperationCode::ID_PROPERTY;
			*operation_name = RNA_property_identifier((PropertyRNA *)prop);
			*operation_name_tag = -1;
		}
		else {
			*type = NodeType::PARAMETERS;
			*operation_code = OperationCode::PARAMETERS_EVAL;
			*operation_name = "";
			*operation_name_tag = -1;
		}
		return true;
	}
	return false;
}

/* Convenience wrapper to find node given just pointer + property. */
Node *Depsgraph::find_node_from_pointer(const PointerRNA *ptr,
                                        const PropertyRNA *prop,
                                        RNAPointerSource source) const
{
	ID *id;
	NodeType node_type;
	const char *component_name, *operation_name;
	OperationCode operation_code;
	int operation_name_tag;
	if (pointer_to_component_node_criteria(
	                 ptr, prop, source,
	                 &id, &node_type, &component_name,
	                 &operation_code, &operation_name, &operation_name_tag))
	{
		IDNode *id_node = find_id_node(id);
		if (id_node == NULL) {
			return NULL;
		}
		ComponentNode *comp_node =
		        id_node->find_component(node_type, component_name);
		if (comp_node == NULL) {
			return NULL;
		}
		if (operation_code == OperationCode::OPERATION) {
			return comp_node;
		}
		return comp_node->find_operation(operation_code,
		                                 operation_name,
		                                 operation_name_tag);
	}
	return NULL;
}

/* Node Management ---------------------------- */

TimeSourceNode *Depsgraph::add_time_source()
{
	if (time_source == NULL) {
		DepsNodeFactory *factory = type_get_factory(NodeType::TIMESOURCE);
		time_source = (TimeSourceNode *)factory->create_node(NULL, "", "Time Source");
	}
	return time_source;
}

TimeSourceNode *Depsgraph::find_time_source() const
{
	return time_source;
}

IDNode *Depsgraph::find_id_node(const ID *id) const
{
	return reinterpret_cast<IDNode *>(BLI_ghash_lookup(id_hash, id));
}

IDNode *Depsgraph::add_id_node(ID *id, ID *id_cow_hint)
{
	BLI_assert((id->tag & LIB_TAG_COPIED_ON_WRITE) == 0);
	IDNode *id_node = find_id_node(id);
	if (!id_node) {
		DepsNodeFactory *factory = type_get_factory(NodeType::ID_REF);
		id_node = (IDNode *)factory->create_node(id, "", id->name);
		id_node->init_copy_on_write(id_cow_hint);
		/* Register node in ID hash.
		 *
		 * NOTE: We address ID nodes by the original ID pointer they are
		 * referencing to. */
		BLI_ghash_insert(id_hash, id, id_node);
		id_nodes.push_back(id_node);
	}
	return id_node;
}

void Depsgraph::clear_id_nodes_conditional(const std::function <bool (ID_Type id_type)>& filter)
{
	for (IDNode *id_node : id_nodes) {
		if (id_node->id_cow == NULL) {
			/* This means builder "stole" ownership of the copy-on-written
			 * datablock for her own dirty needs. */
			continue;
		}
		if (!deg_copy_on_write_is_expanded(id_node->id_cow)) {
			continue;
		}
		const ID_Type id_type = GS(id_node->id_cow->name);
		if (filter(id_type)) {
			id_node->destroy();
		}
	}
}

void Depsgraph::clear_id_nodes()
{
	/* Free memory used by ID nodes. */

	/* Stupid workaround to ensure we free IDs in a proper order. */
	clear_id_nodes_conditional([](ID_Type id_type) { return id_type == ID_SCE; });
	clear_id_nodes_conditional([](ID_Type id_type) { return id_type != ID_PA; });

	for (IDNode *id_node : id_nodes) {
		OBJECT_GUARDED_DELETE(id_node, IDNode);
	}
	/* Clear containers. */
	BLI_ghash_clear(id_hash, NULL, NULL);
	id_nodes.clear();
	/* Clear physics relation caches. */
	clear_physics_relations(this);
}

/* Add new relation between two nodes */
Relation *Depsgraph::add_new_relation(Node *from, Node *to,
                                      const char *description,
                                      int flags)
{
	Relation *rel = NULL;
	if (flags & RELATION_CHECK_BEFORE_ADD) {
		rel = check_nodes_connected(from, to, description);
	}
	if (rel != NULL) {
		rel->flag |= flags;
		return rel;
	}

#ifndef NDEBUG
	if (from->type == NodeType::OPERATION &&
	    to->type == NodeType::OPERATION)
	{
		OperationNode *operation_from = static_cast<OperationNode *>(from);
		OperationNode *operation_to = static_cast<OperationNode *>(to);
		BLI_assert(operation_to->owner->type != NodeType::COPY_ON_WRITE ||
		           operation_from->owner->type == NodeType::COPY_ON_WRITE);
	}
#endif

	/* Create new relation, and add it to the graph. */
	rel = OBJECT_GUARDED_NEW(Relation, from, to, description);
	rel->flag |= flags;
	return rel;
}

Relation *Depsgraph::check_nodes_connected(const Node *from,
                                           const Node *to,
                                           const char *description)
{
	for (Relation *rel : from->outlinks) {
		BLI_assert(rel->from == from);
		if (rel->to != to) {
			continue;
		}
		if (description != NULL && !STREQ(rel->name, description)) {
			continue;
		}
		return rel;
	}
	return NULL;
}

/* ************************ */
/* Relationships Management */

Relation::Relation(Node *from, Node *to, const char *description)
  : from(from),
    to(to),
    name(description),
    flag(0)
{
	/* Hook it up to the nodes which use it.
	 *
	 * NOTE: We register relation in the nodes which this link connects to here
	 * in constructor but we don't unregister it in the destructor.
	 *
	 * Reasoning:
	 *
	 * - Destructor is currently used on global graph destruction, so there's no
	 *   real need in avoiding dangling pointers, all the memory is to be freed
	 *   anyway.
	 *
	 * - Unregistering relation is not a cheap operation, so better to have it
	 *   as an explicit call if we need this. */
	from->outlinks.push_back(this);
	to->inlinks.push_back(this);
}

Relation::~Relation()
{
	/* Sanity check. */
	BLI_assert(from != NULL && to != NULL);
}

void Relation::unlink()
{
	/* Sanity check. */
	BLI_assert(from != NULL && to != NULL);
	remove_from_vector(&from->outlinks, this);
	remove_from_vector(&to->inlinks, this);
}

/* Low level tagging -------------------------------------- */

/* Tag a specific node as needing updates. */
void Depsgraph::add_entry_tag(OperationNode *node)
{
	/* Sanity check. */
	if (node == NULL) {
		return;
	}
	/* Add to graph-level set of directly modified nodes to start searching
	 * from.
	 * NOTE: this is necessary since we have several thousand nodes to play
	 * with. */
	BLI_gset_insert(entry_tags, node);
}

void Depsgraph::clear_all_nodes()
{
	clear_id_nodes();
	if (time_source != NULL) {
		OBJECT_GUARDED_DELETE(time_source, TimeSourceNode);
		time_source = NULL;
	}
}

ID *Depsgraph::get_cow_id(const ID *id_orig) const
{
	IDNode *id_node = find_id_node(id_orig);
	if (id_node == NULL) {
		/* This function is used from places where we expect ID to be either
		 * already a copy-on-write version or have a corresponding copy-on-write
		 * version.
		 *
		 * We try to enforce that in debug builds, for for release we play a bit
		 * safer game here. */
		if ((id_orig->tag & LIB_TAG_COPIED_ON_WRITE) == 0) {
			/* TODO(sergey): This is nice sanity check to have, but it fails
			 * in following situations:
			 *
			 * - Material has link to texture, which is not needed by new
			 *   shading system and hence can be ignored at construction.
			 * - Object or mesh has material at a slot which is not used (for
			 *   example, object has material slot by materials are set to
			 *   object data). */
			// BLI_assert(!"Request for non-existing copy-on-write ID");
		}
		return (ID *)id_orig;
	}
	return id_node->id_cow;
}

}  // namespace DEG

/* **************** */
/* Public Graph API */

/* Initialize a new Depsgraph */
Depsgraph *DEG_graph_new(Scene *scene,
                         ViewLayer *view_layer,
                         eEvaluationMode mode)
{
	DEG::Depsgraph *deg_depsgraph = OBJECT_GUARDED_NEW(DEG::Depsgraph,
	                                                   scene,
	                                                   view_layer,
	                                                   mode);
	return reinterpret_cast<Depsgraph *>(deg_depsgraph);
}

/* Free graph's contents and graph itself */
void DEG_graph_free(Depsgraph *graph)
{
	using DEG::Depsgraph;
	DEG::Depsgraph *deg_depsgraph = reinterpret_cast<DEG::Depsgraph *>(graph);
	OBJECT_GUARDED_DELETE(deg_depsgraph, Depsgraph);
}

bool DEG_is_active(const struct Depsgraph *depsgraph)
{
	if (depsgraph == NULL) {
		/* Happens for such cases as work object in what_does_obaction(),
		 * and sine render pipeline parts. Shouldn't really be accepting
		 * NULL depsgraph, but is quite hard to get proper one in those
		 * cases. */
		return false;
	}
	const DEG::Depsgraph *deg_graph =
	        reinterpret_cast<const DEG::Depsgraph *>(depsgraph);
	return deg_graph->is_active;
}

void DEG_make_active(struct Depsgraph *depsgraph)
{
	DEG::Depsgraph *deg_graph = reinterpret_cast<DEG::Depsgraph *>(depsgraph);
	deg_graph->is_active = true;
	/* TODO(sergey): Copy data from evaluated state to original. */
}

void DEG_make_inactive(struct Depsgraph *depsgraph)
{
	DEG::Depsgraph *deg_graph = reinterpret_cast<DEG::Depsgraph *>(depsgraph);
	deg_graph->is_active = false;
}