#ifndef _RSGEXPRESSION_HPP
#define _RSGEXPRESSION_HPP
/*-------------------------------------------------------------------------
 * drawElements Quality Program Random Shader Generator
 * ----------------------------------------------------
 *
 * Copyright 2014 The Android Open Source Project
 *
 * 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.
 *
 *//*!
 * \file
 * \brief Expressions.
 *
 * Creating expressions:
 *  + Children must be created in in reverse evaluation order.
 *    - Must be tokenized / evaluated taking that order in account.
 *
 * Evaluation:
 *  + Done recursively. (Do we have enough stack?)
 *  + R-values: Nodes must implement getValue() in some way. Value
 *    must be valid after evaluate().
 *  + L-values: Valid writable value access proxy must be returned after
 *    evaluate().
 *//*--------------------------------------------------------------------*/

#include "rsgDefs.hpp"
#include "rsgGeneratorState.hpp"
#include "rsgVariableValue.hpp"
#include "rsgVariable.hpp"
#include "rsgVariableManager.hpp"
#include "rsgExecutionContext.hpp"

namespace rsg
{

// \todo [2011-06-10 pyry] Declare in ShaderParameters?
const float unusedValueWeight = 0.05f;

class Expression
{
public:
	virtual							~Expression			(void);

	// Shader generation API
	virtual Expression*				createNextChild		(GeneratorState& state) = DE_NULL;
	virtual void					tokenize			(GeneratorState& state, TokenStream& str) const	= DE_NULL;

	// Execution API
	virtual void					evaluate			(ExecutionContext& ctx)	= DE_NULL;
	virtual ExecConstValueAccess	getValue			(void) const			= DE_NULL;
	virtual ExecValueAccess			getLValue			(void) const { DE_ASSERT(DE_FALSE); throw Exception("Expression::getLValue(): not L-value node"); }

	static Expression*				createRandom		(GeneratorState& state, ConstValueRangeAccess valueRange);
	static Expression*				createRandomLValue	(GeneratorState& state, ConstValueRangeAccess valueRange);
};

class VariableAccess : public Expression
{
public:
	virtual						~VariableAccess		(void) {}

	Expression*					createNextChild		(GeneratorState& state)							{ DE_UNREF(state); return DE_NULL;						}
	void						tokenize			(GeneratorState& state, TokenStream& str) const	{ DE_UNREF(state); str << Token(m_variable->getName());	}

	void						evaluate			(ExecutionContext& ctx);
	ExecConstValueAccess		getValue			(void) const									{ return m_valueAccess;									}
	ExecValueAccess				getLValue			(void) const									{ return m_valueAccess;									}

protected:
								VariableAccess		(void) : m_variable(DE_NULL) {}

	const Variable*				m_variable;
	ExecValueAccess				m_valueAccess;
};

class VariableRead : public VariableAccess
{
public:
								VariableRead		(GeneratorState& state, ConstValueRangeAccess valueRange);
								VariableRead		(const Variable* variable);
	virtual						~VariableRead		(void) {}

	static float				getWeight			(const GeneratorState& state, ConstValueRangeAccess valueRange);
};

class VariableWrite : public VariableAccess
{
public:
								VariableWrite		(GeneratorState& state, ConstValueRangeAccess valueRange);
	virtual						~VariableWrite		(void) {}

	static float				getWeight			(const GeneratorState& state, ConstValueRangeAccess valueRange);
};

class FloatLiteral : public Expression
{
public:
								FloatLiteral		(GeneratorState& state, ConstValueRangeAccess valueRange);
								FloatLiteral		(float customValue);
	virtual						~FloatLiteral		(void) {}

	Expression*					createNextChild		(GeneratorState& state) { DE_UNREF(state); return DE_NULL; }
	void						tokenize			(GeneratorState& state, TokenStream& str) const;

	static float				getWeight			(const GeneratorState& state, ConstValueRangeAccess valueRange);

	void						evaluate			(ExecutionContext& ctx) { DE_UNREF(ctx); }
	ExecConstValueAccess		getValue			(void) const { return m_value.getValue(VariableType::getScalarType(VariableType::TYPE_FLOAT)); }

private:
	ExecValueStorage			m_value;
};

class IntLiteral : public Expression
{
public:
								IntLiteral			(GeneratorState& state, ConstValueRangeAccess valueRange);
	virtual						~IntLiteral			(void) {}

	Expression*					createNextChild		(GeneratorState& state) { DE_UNREF(state); return DE_NULL; }
	void						tokenize			(GeneratorState& state, TokenStream& str) const;

	static float				getWeight			(const GeneratorState& state, ConstValueRangeAccess valueRange);

	void						evaluate			(ExecutionContext& ctx) { DE_UNREF(ctx); }
	ExecConstValueAccess		getValue			(void) const { return m_value.getValue(VariableType::getScalarType(VariableType::TYPE_INT)); }

private:
	ExecValueStorage			m_value;
};

class BoolLiteral : public Expression
{
public:
								BoolLiteral			(GeneratorState& state, ConstValueRangeAccess valueRange);
								BoolLiteral			(bool customValue);
	virtual						~BoolLiteral		(void) {}

	Expression*					createNextChild		(GeneratorState& state) { DE_UNREF(state); return DE_NULL; }
	void						tokenize			(GeneratorState& state, TokenStream& str) const;

	static float				getWeight			(const GeneratorState& state, ConstValueRangeAccess valueRange);

	void						evaluate			(ExecutionContext& ctx) { DE_UNREF(ctx); }
	ExecConstValueAccess		getValue			(void) const { return m_value.getValue(VariableType::getScalarType(VariableType::TYPE_BOOL)); }

private:
	ExecValueStorage			m_value;
};

class ConstructorOp : public Expression
{
public:
								ConstructorOp		(GeneratorState& state, ConstValueRangeAccess valueRange);
	virtual						~ConstructorOp		(void);

	Expression*					createNextChild		(GeneratorState& state);
	void						tokenize			(GeneratorState& state, TokenStream& str) const;

	static float				getWeight			(const GeneratorState& state, ConstValueRangeAccess valueRange);

	void						evaluate			(ExecutionContext& ctx);
	ExecConstValueAccess		getValue			(void) const { return m_value.getValue(m_valueRange.getType()); }

private:
	ValueRange					m_valueRange;
	ExecValueStorage			m_value;

	std::vector<ValueRange>		m_inputValueRanges;
	std::vector<Expression*>	m_inputExpressions;
};

class AssignOp : public Expression
{
public:
								AssignOp			(GeneratorState& state, ConstValueRangeAccess valueRange);
	virtual						~AssignOp			(void);

	Expression*					createNextChild		(GeneratorState& state);
	void						tokenize			(GeneratorState& state, TokenStream& str) const;

	static float				getWeight			(const GeneratorState& state, ConstValueRangeAccess valueRange);

	// \todo [2011-02-28 pyry] LValue variant of AssignOp
//	static float				getLValueWeight		(const GeneratorState& state, ConstValueRangeAccess valueRange);

	void						evaluate			(ExecutionContext& ctx);
	ExecConstValueAccess		getValue			(void) const { return m_value.getValue(m_valueRange.getType()); }

private:
	ValueRange					m_valueRange;
	ExecValueStorage			m_value;

	Expression*					m_lvalueExpr;
	Expression*					m_rvalueExpr;
};

class ParenOp : public Expression
{
public:
								ParenOp				(GeneratorState& state, ConstValueRangeAccess valueRange);
	virtual						~ParenOp			(void);

	Expression*					createNextChild		(GeneratorState& state);
	void						tokenize			(GeneratorState& state, TokenStream& str) const;

	void						setChild			(Expression* expression);
	static float				getWeight			(const GeneratorState& state, ConstValueRangeAccess valueRange);

	void						evaluate			(ExecutionContext& execCtx)		{ m_child->evaluate(execCtx);	}
	ExecConstValueAccess		getValue			(void) const					{ return m_child->getValue();	}

private:
	ValueRange					m_valueRange;
	Expression*					m_child;
};

class SwizzleOp : public Expression
{
public:
								SwizzleOp			(GeneratorState& state, ConstValueRangeAccess valueRange);
	virtual						~SwizzleOp			(void);

	Expression*					createNextChild		(GeneratorState& state);
	void						tokenize			(GeneratorState& state, TokenStream& str) const;

	static float				getWeight			(const GeneratorState& state, ConstValueRangeAccess valueRange);

	void						evaluate			(ExecutionContext& execCtx);
	ExecConstValueAccess		getValue			(void) const					{ return m_value.getValue(m_outValueRange.getType()); }

private:
	ValueRange					m_outValueRange;
	int							m_numInputElements;
	deUint8						m_swizzle[4];
	Expression*					m_child;
	ExecValueStorage			m_value;
};

class TexLookup : public Expression
{
public:
								TexLookup			(GeneratorState& state, ConstValueRangeAccess valueRange);
	virtual						~TexLookup			(void);

	Expression*					createNextChild		(GeneratorState& state);
	void						tokenize			(GeneratorState& state, TokenStream& str) const;

	static float				getWeight			(const GeneratorState& state, ConstValueRangeAccess valueRange);

	void						evaluate			(ExecutionContext& execCtx);
	ExecConstValueAccess		getValue			(void) const { return m_value.getValue(m_valueType); }

private:
	enum Type
	{
		TYPE_TEXTURE2D,
		TYPE_TEXTURE2D_LOD,
		TYPE_TEXTURE2D_PROJ,
		TYPE_TEXTURE2D_PROJ_LOD,

		TYPE_TEXTURECUBE,
		TYPE_TEXTURECUBE_LOD,

		TYPE_LAST
	};

	Type						m_type;
	const Variable*				m_sampler;
	Expression*					m_coordExpr;
	Expression*					m_lodBiasExpr;
	VariableType				m_valueType;
	ExecValueStorage			m_value;
};

} // rsg

#endif // _RSGEXPRESSION_HPP