/*
 * Copyright 2011-2016 Blender Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef __GRAPH_H__
#define __GRAPH_H__

#include "graph/node.h"
#include "graph/node_type.h"

#include "kernel/kernel_types.h"

#include "util/util_list.h"
#include "util/util_map.h"
#include "util/util_param.h"
#include "util/util_set.h"
#include "util/util_types.h"
#include "util/util_vector.h"

CCL_NAMESPACE_BEGIN

class AttributeRequestSet;
class Scene;
class Shader;
class ShaderInput;
class ShaderOutput;
class ShaderNode;
class ShaderGraph;
class SVMCompiler;
class OSLCompiler;
class OutputNode;
class ConstantFolder;

/* Bump
 *
 * For bump mapping, a node may be evaluated multiple times, using different
 * samples to reconstruct the normal, this indicates the sample position */

enum ShaderBump {
	SHADER_BUMP_NONE,
	SHADER_BUMP_CENTER,
	SHADER_BUMP_DX,
	SHADER_BUMP_DY
};

/* Identifiers for some special node types.
 *
 * The graph needs to identify these in the clean function.
 * Cannot use dynamic_cast, as this is disabled for OSL. */

enum ShaderNodeSpecialType {
	SHADER_SPECIAL_TYPE_NONE,
	SHADER_SPECIAL_TYPE_PROXY,
	SHADER_SPECIAL_TYPE_AUTOCONVERT,
	SHADER_SPECIAL_TYPE_GEOMETRY,
	SHADER_SPECIAL_TYPE_SCRIPT,
	SHADER_SPECIAL_TYPE_IMAGE_SLOT,
	SHADER_SPECIAL_TYPE_CLOSURE,
	SHADER_SPECIAL_TYPE_COMBINE_CLOSURE,
	SHADER_SPECIAL_TYPE_OUTPUT,
	SHADER_SPECIAL_TYPE_BUMP,
};

/* Input
 *
 * Input socket for a shader node. May be linked to an output or not. If not
 * linked, it will either get a fixed default value, or e.g. a texture
 * coordinate. */

class ShaderInput {
public:
	ShaderInput(const SocketType& socket_type_, ShaderNode* parent_)
	: socket_type(socket_type_), parent(parent_), link(NULL), stack_offset(SVM_STACK_INVALID)
	{}

	ustring name() { return socket_type.ui_name; }
	int flags() { return socket_type.flags; }
	SocketType::Type type() { return socket_type.type; }

	void set(float f) { ((Node*)parent)->set(socket_type, f); }
	void set(float3 f) { ((Node*)parent)->set(socket_type, f); }

	const SocketType& socket_type;
	ShaderNode *parent;
	ShaderOutput *link;
	int stack_offset; /* for SVM compiler */
};

/* Output
 *
 * Output socket for a shader node. */

class ShaderOutput {
public:
	ShaderOutput(const SocketType& socket_type_, ShaderNode* parent_)
	: socket_type(socket_type_), parent(parent_), stack_offset(SVM_STACK_INVALID)
	{}

	ustring name() { return socket_type.ui_name; }
	SocketType::Type type() { return socket_type.type; }

	const SocketType& socket_type;
	ShaderNode *parent;
	vector<ShaderInput*> links;
	int stack_offset; /* for SVM compiler */
};

/* Node
 *
 * Shader node in graph, with input and output sockets. This is the virtual
 * base class for all node types. */

class ShaderNode : public Node {
public:
	explicit ShaderNode(const NodeType *type);
	virtual ~ShaderNode();

	void create_inputs_outputs(const NodeType *type);

	ShaderInput *input(const char *name);
	ShaderOutput *output(const char *name);
	ShaderInput *input(ustring name);
	ShaderOutput *output(ustring name);

	virtual ShaderNode *clone() const = 0;
	virtual void attributes(Shader *shader, AttributeRequestSet *attributes);
	virtual void compile(SVMCompiler& compiler) = 0;
	virtual void compile(OSLCompiler& compiler) = 0;

	/* ** Node optimization ** */
	/* Check whether the node can be replaced with single constant. */
	virtual void constant_fold(const ConstantFolder& /*folder*/) {}

	/* Simplify settings used by artists to the ones which are simpler to
	 * evaluate in the kernel but keep the final result unchanged.
	 */
	virtual void simplify_settings(Scene * /*scene*/) {};

	virtual bool has_surface_emission() { return false; }
	virtual bool has_surface_transparent() { return false; }
	virtual bool has_surface_bssrdf() { return false; }
	virtual bool has_bump() { return false; }
	virtual bool has_bssrdf_bump() { return false; }
	virtual bool has_spatial_varying() { return false; }
	virtual bool has_object_dependency() { return false; }
	virtual bool has_integrator_dependency() { return false; }
	virtual bool has_volume_support() { return false; }
	vector<ShaderInput*> inputs;
	vector<ShaderOutput*> outputs;

	int id; /* index in graph node array */
	ShaderBump bump; /* for bump mapping utility */
	
	ShaderNodeSpecialType special_type;	/* special node type */

	/* ** Selective nodes compilation ** */

	/* TODO(sergey): More explicitly mention in the function names
	 * that those functions are for selective compilation only?
	 */

	/* Nodes are split into several groups, group of level 0 contains
	 * nodes which are most commonly used, further levels are extension
	 * of previous one and includes less commonly used nodes.
	 */
	virtual int get_group() { return NODE_GROUP_LEVEL_0; }

	/* Node feature are used to disable huge nodes inside the group,
	 * so it's possible to disable huge nodes inside of the required
	 * nodes group.
	 */
	virtual int get_feature() { return bump == SHADER_BUMP_NONE ? 0 : NODE_FEATURE_BUMP; }

	/* Get closure ID to which the node compiles into. */
	virtual ClosureType get_closure_type() { return CLOSURE_NONE_ID; }

	/* Check whether settings of the node equals to another one.
	 *
	 * This is mainly used to check whether two nodes can be merged
	 * together. Meaning, runtime stuff like node id and unbound slots
	 * will be ignored for comparison.
	 *
	 * NOTE: If some node can't be de-duplicated for whatever reason it
	 * is to be handled in the subclass.
	 */
	virtual bool equals(const ShaderNode& other);
};


/* Node definition utility macros */

#define SHADER_NODE_CLASS(type) \
	NODE_DECLARE \
	type(); \
	virtual ShaderNode *clone() const { return new type(*this); } \
	virtual void compile(SVMCompiler& compiler); \
	virtual void compile(OSLCompiler& compiler); \

#define SHADER_NODE_NO_CLONE_CLASS(type) \
	NODE_DECLARE \
	type(); \
	virtual void compile(SVMCompiler& compiler); \
	virtual void compile(OSLCompiler& compiler); \

#define SHADER_NODE_BASE_CLASS(type) \
	virtual ShaderNode *clone() const { return new type(*this); } \
	virtual void compile(SVMCompiler& compiler); \
	virtual void compile(OSLCompiler& compiler); \

class ShaderNodeIDComparator
{
public:
	bool operator()(const ShaderNode *n1, const ShaderNode *n2) const
	{
		return n1->id < n2->id;
	}
};

typedef set<ShaderNode*, ShaderNodeIDComparator> ShaderNodeSet;
typedef map<ShaderNode*, ShaderNode*, ShaderNodeIDComparator> ShaderNodeMap;

/* Graph
 *
 * Shader graph of nodes. Also does graph manipulations for default inputs,
 * bump mapping from displacement, and possibly other things in the future. */

class ShaderGraph {
public:
	list<ShaderNode*> nodes;
	size_t num_node_ids;
	bool finalized;
	bool simplified;

	ShaderGraph();
	~ShaderGraph();

	ShaderNode *add(ShaderNode *node);
	OutputNode *output();

	void connect(ShaderOutput *from, ShaderInput *to);
	void disconnect(ShaderOutput *from);
	void disconnect(ShaderInput *to);
	void relink(ShaderNode *node, ShaderOutput *from, ShaderOutput *to);

	void remove_proxy_nodes();
	void simplify(Scene *scene);
	void finalize(Scene *scene,
	              bool do_bump = false,
	              bool do_simplify = false,
	              bool bump_in_object_space = false);

	int get_num_closures();

	void dump_graph(const char *filename);

protected:
	typedef pair<ShaderNode* const, ShaderNode*> NodePair;

	void find_dependencies(ShaderNodeSet& dependencies, ShaderInput *input);
	void clear_nodes();
	void copy_nodes(ShaderNodeSet& nodes, ShaderNodeMap& nnodemap);

	void break_cycles(ShaderNode *node, vector<bool>& visited, vector<bool>& on_stack);
	void bump_from_displacement(bool use_object_space);
	void refine_bump_nodes();
	void default_inputs(bool do_osl);
	void transform_multi_closure(ShaderNode *node, ShaderOutput *weight_out, bool volume);

	/* Graph simplification routines. */
	void clean(Scene *scene);
	void constant_fold();
	void simplify_settings(Scene *scene);
	void deduplicate_nodes();
	void verify_volume_output();
};

CCL_NAMESPACE_END

#endif /* __GRAPH_H__ */