/*
 * ***** 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): None Yet
 *
 * ***** END GPL LICENSE BLOCK *****
 */

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

#include "intern/eval/deg_eval_flush.h"

// TODO(sergey): Use some sort of wrapper.
#include <deque>

#include "BLI_utildefines.h"
#include "BLI_task.h"
#include "BLI_ghash.h"

extern "C" {
#include "DNA_object_types.h"
} /* extern "C" */

#include "DEG_depsgraph.h"

#include "intern/nodes/deg_node.h"
#include "intern/nodes/deg_node_component.h"
#include "intern/nodes/deg_node_id.h"
#include "intern/nodes/deg_node_operation.h"

#include "intern/depsgraph_intern.h"
#include "util/deg_util_foreach.h"

namespace DEG {

enum {
	ID_STATE_NONE     = 0,
	ID_STATE_MODIFIED = 1,
};

enum {
	COMPONENT_STATE_NONE      = 0,
	COMPONENT_STATE_SCHEDULED = 1,
	COMPONENT_STATE_DONE      = 2,
};

typedef std::deque<OperationDepsNode *> FlushQueue;

namespace {

// TODO(sergey): De-duplicate with depsgraph_tag,cc
void lib_id_recalc_tag(Main *bmain, ID *id)
{
	id->recalc |= ID_RECALC;
	DEG_id_type_tag(bmain, GS(id->name));
}

void lib_id_recalc_data_tag(Main *bmain, ID *id)
{
	id->recalc |= ID_RECALC_DATA;
	DEG_id_type_tag(bmain, GS(id->name));
}

void flush_init_operation_node_func(void *data_v,
                                    int i,
                                    const ParallelRangeTLS * /*tls*/)
{
	Depsgraph *graph = (Depsgraph *)data_v;
	OperationDepsNode *node = graph->operations[i];
	node->scheduled = false;
}

void flush_init_id_node_func(void *data_v,
                             int i,
                             const ParallelRangeTLS * /*tls*/)
{
	Depsgraph *graph = (Depsgraph *)data_v;
	IDDepsNode *id_node = graph->id_nodes[i];
	id_node->done = ID_STATE_NONE;
	GHASH_FOREACH_BEGIN(ComponentDepsNode *, comp_node, id_node->components)
		comp_node->done = COMPONENT_STATE_NONE;
	GHASH_FOREACH_END();
}

BLI_INLINE void flush_prepare(Depsgraph *graph)
{
	{
		const int num_operations = graph->operations.size();
		ParallelRangeSettings settings;
		BLI_parallel_range_settings_defaults(&settings);
		settings.use_threading = (num_operations > 256);
		BLI_task_parallel_range(0, num_operations,
		                        graph,
		                        flush_init_operation_node_func,
		                        &settings);
	}
	{
		const int num_id_nodes = graph->id_nodes.size();
		ParallelRangeSettings settings;
		BLI_parallel_range_settings_defaults(&settings);
		settings.use_threading = (num_id_nodes > 256);
		BLI_task_parallel_range(0, num_id_nodes,
		                        graph,
		                        flush_init_id_node_func,
		                        &settings);
	}
}

BLI_INLINE void flush_schedule_entrypoints(Depsgraph *graph, FlushQueue *queue)
{
	GSET_FOREACH_BEGIN(OperationDepsNode *, op_node, graph->entry_tags)
	{
		queue->push_back(op_node);
		op_node->scheduled = true;
	}
	GSET_FOREACH_END();
}

BLI_INLINE void flush_handle_id_node(IDDepsNode *id_node)
{
	id_node->done = ID_STATE_MODIFIED;
}

/* TODO(sergey): We can reduce number of arguments here. */
BLI_INLINE void flush_handle_component_node(Depsgraph * /*graph*/,
                                            IDDepsNode *id_node,
                                            ComponentDepsNode *comp_node,
                                            FlushQueue *queue)
{
	/* We only handle component once. */
	if (comp_node->done == COMPONENT_STATE_DONE) {
		return;
	}
	comp_node->done = COMPONENT_STATE_DONE;
	/* Tag all required operations in component for update.  */
	foreach (OperationDepsNode *op, comp_node->operations) {
		op->flag |= DEPSOP_FLAG_NEEDS_UPDATE;
	}
	if (GS(id_node->id->name) == ID_OB) {
		Object *object = (Object *)id_node->id;
		/* This code is used to preserve those areas which does
		 * direct object update,
		 *
		 * Plus it ensures visibility changes and relations and
		 * layers visibility update has proper flags to work with.
		 */
		switch (comp_node->type) {
			case DEG_NODE_TYPE_UNDEFINED:
			case DEG_NODE_TYPE_OPERATION:
			case DEG_NODE_TYPE_TIMESOURCE:
			case DEG_NODE_TYPE_ID_REF:
			case DEG_NODE_TYPE_SEQUENCER:
			case NUM_DEG_NODE_TYPES:
				/* Ignore, does not translate to object component. */
				BLI_assert(!"This should never happen!");
				break;
			case DEG_NODE_TYPE_ANIMATION:
				object->recalc |= OB_RECALC_TIME;
				break;
			case DEG_NODE_TYPE_TRANSFORM:
				object->recalc |= OB_RECALC_OB;
				break;
			case DEG_NODE_TYPE_GEOMETRY:
			case DEG_NODE_TYPE_EVAL_POSE:
			case DEG_NODE_TYPE_BONE:
			case DEG_NODE_TYPE_EVAL_PARTICLES:
			case DEG_NODE_TYPE_SHADING:
			case DEG_NODE_TYPE_CACHE:
			case DEG_NODE_TYPE_PROXY:
				object->recalc |= OB_RECALC_DATA;
				break;
			case DEG_NODE_TYPE_PARAMETERS:
				break;
		}
	}
	/* When some target changes bone, we might need to re-run the
	 * whole IK solver, otherwise result might be unpredictable.
	 */
	if (comp_node->type == DEG_NODE_TYPE_BONE) {
		ComponentDepsNode *pose_comp =
		        id_node->find_component(DEG_NODE_TYPE_EVAL_POSE);
		BLI_assert(pose_comp != NULL);
		if (pose_comp->done == COMPONENT_STATE_NONE) {
			queue->push_front(pose_comp->get_entry_operation());
			pose_comp->done = COMPONENT_STATE_SCHEDULED;
		}
	}
}

/* Schedule children of the given operation node for traversal.
 *
 * One of the children will by-pass the queue and will be returned as a function
 * return value, so it can start being handled right away, without building too
 * much of a queue.
 */
BLI_INLINE OperationDepsNode *flush_schedule_children(
        OperationDepsNode *op_node,
        FlushQueue *queue)
{
	OperationDepsNode *result = NULL;
	foreach (DepsRelation *rel, op_node->outlinks) {
		OperationDepsNode *to_node = (OperationDepsNode *)rel->to;
		if (to_node->scheduled == false) {
			if (result != NULL) {
				queue->push_front(to_node);
			}
			else {
				result = to_node;
			}
			to_node->scheduled = true;
		}
	}
	return result;
}

BLI_INLINE void flush_editors_id_update(Main *bmain,
                                        Depsgraph *graph)
{
	foreach (IDDepsNode *id_node, graph->id_nodes) {
		if (id_node->done != ID_STATE_MODIFIED) {
			continue;
		}
		/* TODO(sergey): Do we need to pass original or evaluated ID here? */
		ID *id = id_node->id;
		deg_editors_id_update(bmain, id);
		lib_id_recalc_tag(bmain, id);
		/* TODO(sergey): For until we've got proper data nodes in the graph. */
		lib_id_recalc_data_tag(bmain, id);
	}
}

}  // namespace

/* Flush updates from tagged nodes outwards until all affected nodes
 * are tagged.
 */
void deg_graph_flush_updates(Main *bmain, Depsgraph *graph)
{
	/* Sanity checks. */
	BLI_assert(bmain != NULL);
	BLI_assert(graph != NULL);
	/* Nothing to update, early out. */
	if (BLI_gset_size(graph->entry_tags) == 0) {
		return;
	}
	/* Reset all flags, get ready for the flush. */
	flush_prepare(graph);
	/* Starting from the tagged "entry" nodes, flush outwards. */
	FlushQueue queue;
	flush_schedule_entrypoints(graph, &queue);
	/* Do actual flush. */
	while (!queue.empty()) {
		OperationDepsNode *op_node = queue.front();
		queue.pop_front();
		while (op_node != NULL) {
			/* Tag operation as required for update. */
			op_node->flag |= DEPSOP_FLAG_NEEDS_UPDATE;
			/* Inform corresponding ID and component nodes about the change. */
			ComponentDepsNode *comp_node = op_node->owner;
			IDDepsNode *id_node = comp_node->owner;
			flush_handle_id_node(id_node);
			flush_handle_component_node(graph,
			                            id_node,
			                            comp_node,
			                            &queue);
			/* Flush to nodes along links. */
			op_node = flush_schedule_children(op_node, &queue);
		}
	}
	/* Inform editors about all changes. */
	flush_editors_id_update(bmain, graph);
}

static void graph_clear_func(void *data_v,
                             int i,
                             const ParallelRangeTLS * /*tls*/)
{
	Depsgraph *graph = (Depsgraph *)data_v;
	OperationDepsNode *node = graph->operations[i];
	/* Clear node's "pending update" settings. */
	node->flag &= ~(DEPSOP_FLAG_DIRECTLY_MODIFIED | DEPSOP_FLAG_NEEDS_UPDATE);
}

/* Clear tags from all operation nodes. */
void deg_graph_clear_tags(Depsgraph *graph)
{
	/* Go over all operation nodes, clearing tags. */
	const int num_operations = graph->operations.size();
	const bool do_threads = num_operations > 256;
	ParallelRangeSettings settings;
	BLI_parallel_range_settings_defaults(&settings);
	settings.use_threading = do_threads;
	BLI_task_parallel_range(0, num_operations,
	                        graph,
	                        graph_clear_func,
	                        &settings);
	/* Clear any entry tags which haven't been flushed. */
	BLI_gset_clear(graph->entry_tags, NULL);
}

}  // namespace DEG