#include "externals.hh"
#include "opast.hh"
#include <ebcl/Algorithms.hh>

using namespace ebcl;
using namespace opast;


/*= A_Node ===================================================================*/

A_Node::A_Node( const E_Type type ,
		A_Node* const parent ) noexcept
	: type_( type ) , parent_( parent )
{
	assert( ( type == ROOT && !parent ) || ( type != ROOT && parent ) );
}

A_Node::~A_Node( ) { }

T_RootNode& A_Node::root( ) const noexcept
{
	A_Node const* node( this );
	while ( node->parent_ ) {
		node = node->parent_;
	}
	assert( node );
	assert( node->type_ == ROOT );
	return *dynamic_cast< T_RootNode* >(
			const_cast< A_Node* >( node ) );
}

/*----------------------------------------------------------------------------*/

A_Node* opast::ASTVisitorBrowser(
		A_Node& node ,
		const uint32_t child ) noexcept
{
	switch ( node.type( ) ) {

	    // Root node
	    case A_Node::ROOT: {
		auto& n( (T_RootNode&) node );
		if ( child < n.nFunctions( ) ) {
			return &n.function( child );
		}
		break;
	    }

	    // Functions / special blocks
	    case A_Node::DECL_FN: case A_Node::DECL_INIT: case A_Node::DECL_FRAME:
		if ( child == 0 ) {
			auto& n( (A_FuncNode&) node );
			return &n.instructions( );
		}
		break;

	    // Instruction list
	    case A_Node::ILIST: {
		auto& n( (T_InstrListNode&) node );
		if ( child < n.size( ) ) {
			return &n.node( child );
		}
		break;
	    }

	    // Unary operators
	    case A_Node::EXPR_NEG: case A_Node::EXPR_INV:
	    case A_Node::EXPR_NOT: case A_Node::EXPR_SIN:
	    case A_Node::EXPR_COS: case A_Node::EXPR_TAN:
	    case A_Node::EXPR_SQRT: case A_Node::EXPR_EXP:
	    case A_Node::EXPR_LN:
	    {
		auto& n( (T_UnaryOperatorNode&) node );
		if ( child == 0 && n.hasArgument( ) ) {
			return &n.argument( );
		}
		break;
	    }

	    // Binary operators
	    case A_Node::EXPR_ADD: case A_Node::EXPR_SUB:
	    case A_Node::EXPR_MUL: case A_Node::EXPR_DIV:
	    case A_Node::EXPR_POW:
	    case A_Node::EXPR_CMP_EQ: case A_Node::EXPR_CMP_NE:
	    case A_Node::EXPR_CMP_GT: case A_Node::EXPR_CMP_GE:
	    case A_Node::EXPR_CMP_LT: case A_Node::EXPR_CMP_LE:
	    {
		auto& n( (T_BinaryOperatorNode&) node );
		if ( child == 0 && n.hasLeft( ) ) {
			return &n.left( );
		}
		if ( child < 2 && n.hasRight( ) ) {
			return &n.right( );
		}
		break;
	    }

	    // Nodes that do not have children
	    case A_Node::EXPR_ID: case A_Node::EXPR_CONST:
	    case A_Node::EXPR_INPUT:
	    case A_Node::OP_PROGRAM: case A_Node::OP_PIPELINE:
	    case A_Node::OP_INPUT: case A_Node::OP_FULLSCREEN:
	    case A_Node::OP_USE_FRAMEBUFFER: case A_Node::OP_USE_PIPELINE:
	    case A_Node::OP_USE_PROGRAM: case A_Node::OP_USE_TEXTURE:
		break;

	    // Profile instruction
	    case A_Node::OP_PROFILE:
		if ( child == 0 ) {
			return &( ((T_ProfileInstrNode&) node).instructions( ) );
		}
		break;

	    // Call instruction
	    case A_Node::OP_CALL:
	    {
		auto& n( (T_CallInstrNode&) node );
		if ( child < n.arguments( ) ) {
			return &n.argument( child );
		}
		break;
	    }

	    // Conditional instruction
	    case A_Node::OP_COND:
	    {
		auto& n( (T_CondInstrNode&) node );
		auto c = child;
		if ( n.hasExpression( ) ) {
			if ( c == 0 ) {
				return &n.expression( );
			}
			c --;
		}
		if ( !n.cases( ).empty( ) ) {
			if ( c < n.cases( ).size( ) ) {
				return &n.getCase( n.cases( )[ c ] );
			}
			c -= n.cases( ).size( );
		}
		if ( n.hasDefaultCase( ) && c == 0 ) {
			return &n.defaultCase( );
		}
		break;
	    }

	    // Set instruction
	    case A_Node::OP_SET:
		if ( child == 0 ) {
			auto& n( (T_SetInstrNode&) node );
			if ( n.hasExpression( ) ) {
				return &n.expression( );
			}
		}
		break;

	    // Texture instruction
	    case A_Node::OP_TEXTURE:
	    {
		auto& n( (T_TextureInstrNode&) node );
		auto c = child;
		if ( n.hasWidth( ) ) {
			if ( c == 0 ) {
				return &n.width( );
			}
			c --;
		}
		if ( n.hasHeight( ) && c == 0 ) {
			return &n.height( );
		}
		break;
	    }

	    // Viewport instruction
	    case A_Node::OP_VIEWPORT:
	    {
		auto& n( (T_ViewportInstrNode&) node );
		auto c = child;
		for ( int i = 0 ; i < 4 ; i ++ ) {
			T_ViewportInstrNode::E_Parameter p{
				T_ViewportInstrNode::E_Parameter( i ) };
			if ( n.hasParameter( p ) ) {
				if ( c == 0 ) {
					return &n.parameter( p );
				}
				c --;
			}
		}
		break;
	    }

	}
	return nullptr;
}


/*= A_FuncNode ===============================================================*/

A_FuncNode::A_FuncNode(
		const bool isInit ,
		T_RootNode* const root ) noexcept
	: A_Node( isInit ? DECL_INIT : DECL_FRAME , root ) ,
		name_( isInit ? "*init*" : "*frame*" ) ,
		instructions_( *this )
{ }

A_FuncNode::A_FuncNode(
		T_String const& name ,
		T_RootNode* const root ) noexcept
	: A_Node( DECL_FN , root ) , name_( name ) ,
		instructions_( *this )
{ }


/*= T_RootNode ===============================================================*/

T_RootNode::T_RootNode( ) noexcept
	: A_Node( ROOT , nullptr ) , functions_(
			[]( T_OwnPtr< A_FuncNode > const& f ) {
				return f->name( );
			} )
{ }

T_RootNode::T_AddFunctionResult T_RootNode::addFunction(
		T_OwnPtr< A_FuncNode >& function ) noexcept
{
	T_String const& fn( function->name( ) );
	auto const* const pf( functions_.get( fn ) );
	if ( !pf ) {
		auto* const rv( function.get( ) );
		functions_.add( std::move( function ) );
		return *rv;
	}

	T_String dfn;
	uint32_t dupCtr( 0 );
	do {
		T_StringBuilder fnsb;
		fnsb << fn << " dup " << dupCtr ++;
		dfn = std::move( fnsb );
	} while ( functions_.contains( dfn ) );

	T_OwnPtr< A_FuncNode > df( NewOwned< T_FuncNode >( dfn , *this ) );
	auto* const rv( df.get( ) );
	functions_.add( std::move( df ) );
	return T_AddFunctionResult{ *rv , (*pf)->location( ) };
}


/*= T_FuncNode ===============================================================*/

T_Optional< T_SRDLocation > T_FuncNode::addArgument(
		T_SRDToken const& token ) noexcept
{
	assert( token.type( ) == E_SRDTokenType::WORD );
	assert( token.hasLocation( ) );

	const auto pnp( argNames_.indexOf( token.stringValue( ) ) );
	if ( pnp != -1 ) {
		return argLocations_[ pnp ];
	}
	argNames_.add( token.stringValue( ) );
	argLocations_.add( token.location( ) );
	return {};
}


/*= T_PipelineInstrNode ======================================================*/

T_Optional< T_SRDLocation > T_PipelineInstrNode::addProgram(
		T_SRDToken const& pidToken ) noexcept
{
	T_String const& name( pidToken.stringValue( ) );
	const auto pIndex( pids_.indexOf( name ) );
	if ( pIndex != -1 ) {
		return pidLocations_[ pIndex ];
	}
	pids_.add( name );
	pidLocations_.add( pidToken.location( ) );
	return {};
}


/*= T_UnaryOperatorNode ======================================================*/

T_UnaryOperatorNode::T_UnaryOperatorNode(
		A_Node& parent ,
		const E_Operator op ) noexcept
	: A_ExpressionNode( ([op]() {
		switch ( op ) {
			case NEG: return EXPR_NEG;
			case INV: return EXPR_INV;
			case NOT: return EXPR_NOT;
			case SIN: return EXPR_SIN;
			case COS: return EXPR_COS;
			case TAN: return EXPR_TAN;
			case SQRT: return EXPR_SQRT;
			case EXP: return EXPR_EXP;
			case LN: return EXPR_LN;
		}
		std::abort( );
	})( ) , parent ) , op_( op )
{ }


/*= T_BinaryOperatorNode =====================================================*/

T_BinaryOperatorNode::T_BinaryOperatorNode(
		A_Node& parent ,
		const E_Operator op ) noexcept
	: A_ExpressionNode( ([op]() {
		switch ( op ) {
			case ADD: return EXPR_ADD;
			case SUB: return EXPR_SUB;
			case MUL: return EXPR_MUL;
			case DIV: return EXPR_DIV;
			case POW: return EXPR_POW;
			case CMP_EQ: return EXPR_CMP_EQ;
			case CMP_NE: return EXPR_CMP_NE;
			case CMP_GT: return EXPR_CMP_GT;
			case CMP_GE: return EXPR_CMP_GE;
			case CMP_LT: return EXPR_CMP_LT;
			case CMP_LE: return EXPR_CMP_LE;
		}
		std::abort( );
	})( ) , parent ) , op_( op )
{ }


/*= T_Parser =================================================================*/

namespace {

struct T_ParserImpl_
{
	enum class E_InstrType {
		CALL ,
		FULLSCREEN ,
		IF ,
		INPUT ,
		PIPELINE ,
		PROFILE ,
		PROGRAM ,
		SET ,
		TEXTURE ,
		USE_FRAMEBUFFER ,
		USE_PIPELINE ,
		USE_PROGRAM ,
		USE_TEXTURE ,
		VIEWPORT ,
	};

	const T_KeyValueTable< T_String , E_InstrType > instrMap{ ([]() {
		T_KeyValueTable< T_String , E_InstrType > temp{ 256 , 64 , 64 };
		const auto add{ [&temp]( char const* name , E_InstrType it ) {
			temp.add( T_String::Pooled( name ) , it );
		} };

		add( "call" , E_InstrType::CALL );
		add( "fullscreen" , E_InstrType::FULLSCREEN );
		add( "if" , E_InstrType::IF );
		add( "input" , E_InstrType::INPUT );
		add( "pipeline" , E_InstrType::PIPELINE );
		add( "profiling" , E_InstrType::PROFILE );
		add( "program" , E_InstrType::PROGRAM );
		add( "set" , E_InstrType::SET );
		add( "texture" , E_InstrType::TEXTURE );
		add( "use-framebuffer" , E_InstrType::USE_FRAMEBUFFER );
		add( "use-pipeline" , E_InstrType::USE_PIPELINE );
		add( "use-program" , E_InstrType::USE_PROGRAM );
		add( "use-texture" , E_InstrType::USE_TEXTURE );
		add( "viewport" , E_InstrType::VIEWPORT );

		return temp;
	})( ) };

	const T_KeyValueTable< T_String , T_UnaryOperatorNode::E_Operator > unaryOpMap{ ([]() {
		T_KeyValueTable< T_String , T_UnaryOperatorNode::E_Operator > temp{ 64 , 32 , 32 };
		const auto add{ [&temp]( char const* name ,
				const T_UnaryOperatorNode::E_Operator it ) {
			temp.add( T_String::Pooled( name ) , it );
		} };

		add( "neg" , T_UnaryOperatorNode::NEG );
		add( "inv" , T_UnaryOperatorNode::INV );
		add( "not" , T_UnaryOperatorNode::NOT );
		add( "sin" , T_UnaryOperatorNode::SIN );
		add( "cos" , T_UnaryOperatorNode::COS );
		add( "tan" , T_UnaryOperatorNode::TAN );
		add( "sqrt" , T_UnaryOperatorNode::SQRT );
		add( "exp" , T_UnaryOperatorNode::EXP );
		add( "ln" , T_UnaryOperatorNode::LN );

		return temp;
	})( ) };

	const T_KeyValueTable< T_String , E_TexType > texTypeMap{ ([]() {
		T_KeyValueTable< T_String , E_TexType > temp{ 64 , 16 , 16 };
		const auto add{ [&temp]( char const* name ,
				const E_TexType it ) {
			temp.add( T_String::Pooled( name ) , it );
		} };

		add( "rgba-nu8" , E_TexType::RGBA8 );
		add( "rgba-f16" , E_TexType::RGBA16F );
		add( "rgb-nu8" , E_TexType::RGB8 );
		add( "rgb-f16" , E_TexType::RGB16F );
		add( "r-nu8" , E_TexType::R8 );
		add( "r-f16" , E_TexType::R16F );

		return temp;
	})( ) };

	const T_KeyValueTable< T_String , T_BinaryOperatorNode::E_Operator > binOpMap{ ([]() {
		T_KeyValueTable< T_String , T_BinaryOperatorNode::E_Operator > temp{ 64 , 32 , 32 };
		const auto add{ [&temp]( char const* name ,
				const T_BinaryOperatorNode::E_Operator it ) {
			temp.add( T_String::Pooled( name ) , it );
		} };

		add( "add" , T_BinaryOperatorNode::ADD );
		add( "sub" , T_BinaryOperatorNode::SUB );
		add( "mul" , T_BinaryOperatorNode::MUL );
		add( "div" , T_BinaryOperatorNode::DIV );
		add( "pow" , T_BinaryOperatorNode::POW );
		add( "cmp-eq" , T_BinaryOperatorNode::CMP_EQ );
		add( "cmp-ne" , T_BinaryOperatorNode::CMP_NE );
		add( "cmp-gt" , T_BinaryOperatorNode::CMP_GT );
		add( "cmp-ge" , T_BinaryOperatorNode::CMP_GE );
		add( "cmp-lt" , T_BinaryOperatorNode::CMP_LT );
		add( "cmp-le" , T_BinaryOperatorNode::CMP_LE );

		return temp;
	})( ) };

	// ---------------------------------------------------------------------

	T_OwnPtr< T_RootNode >& root;
	T_Array< T_SRDError >& errors;
	T_Visitor< A_Node > visitor{ opast::ASTVisitorBrowser };
	T_MultiArray< uint32_t > calls;
	T_Visitor< uint32_t , uint32_t > callGraphVisitor{
			[this]( uint32_t v , uint32_t child ) -> T_Optional< uint32_t > {
				const uint32_t nc( calls.sizeOf( v ) );
				if ( child < nc ) {
					return calls.get( v , child );
				}
				return {};
			} };

	T_ParserImpl_( T_Array< T_SRDError >* errors ,
			T_OwnPtr< T_RootNode >* root ) noexcept;

	// ---------------------------------------------------------------------

	void parseTopLevel( T_SRDList const& list ) noexcept;
	void parseFunction( T_SRDList const& funcList ) noexcept;
	void parseFunctionArguments(
			T_FuncNode& function ,
			T_SRDToken const& argsToken ) noexcept;

	// ---------------------------------------------------------------------

	void parseInstructions(
			T_InstrListNode& instructions ,
			T_SRDList const& input ,
			uint32_t start ) noexcept;
	P_InstrListNode parseBlock(
			A_Node& parent ,
			T_SRDToken const& block ) noexcept;

	// ---------------------------------------------------------------------

#define M_DPARSER_( NAME ) \
	void parse##NAME##Instruction( \
			T_InstrListNode& instructions , \
			T_SRDList const& input ) noexcept

	M_DPARSER_( Call );
	M_DPARSER_( If );
	M_DPARSER_( Input );
	M_DPARSER_( Pipeline );
	M_DPARSER_( Profile );
	M_DPARSER_( Program );
	M_DPARSER_( Set );
	M_DPARSER_( Texture );
	M_DPARSER_( UseFramebuffer );
	M_DPARSER_( UsePipeline );
	M_DPARSER_( UseProgram );
	void parseUseCommon(
			T_InstrListNode& instructions ,
			T_SRDList const& input ,
			T_UseInstrNode::E_Type type ) noexcept;
	M_DPARSER_( UseTexture );
	M_DPARSER_( Viewport );

#undef M_DPARSER_

	// ---------------------------------------------------------------------

	P_ExpressionNode parseExpression(
			A_Node& parent ,
			T_SRDToken const& token ) noexcept;
	P_ExpressionNode parseOperation(
			A_Node& parent ,
			T_SRDList const& opList ) noexcept;
	P_ExpressionNode parseBinOp(
			A_Node& parent ,
			T_SRDList const& opList ,
			T_BinaryOperatorNode::E_Operator op ) noexcept;
	P_ExpressionNode parseUnaryOp(
			A_Node& parent ,
			T_SRDList const& opList ,
			T_UnaryOperatorNode::E_Operator op ) noexcept;
};

/*----------------------------------------------------------------------------*/

inline T_ParserImpl_::T_ParserImpl_(
		T_Array< T_SRDError >* const errors ,
		T_OwnPtr< T_RootNode >* const root ) noexcept
	: root( *root ) , errors( *errors )
{ }

/*----------------------------------------------------------------------------*/

void T_ParserImpl_::parseTopLevel(
		T_SRDList const& input ) noexcept
{
	for ( auto const& t : input ) {
		if ( t.type( ) == E_SRDTokenType::LIST && t.list( ).size( ) > 0 ) {
			parseFunction( t.list( ) );
		} else {
			errors.addNew( "function, init or frame list expected" ,
					t.location( ) );
		}
	}
	if ( !errors.empty( ) ) {
		return;
	}

	const T_SRDLocation missingErrLoc( ([&input]() {
		if ( input.size( ) != 0 ) {
			return T_SRDLocation( input[ 0 ].location( ).source( ) , 1 , 1 );
		}
		return T_SRDLocation{};
	})( ));
	if ( !root->hasInit( ) ) {
		errors.addNew( "no initialisation block" , missingErrLoc );
	}
	if ( !root->hasFrame( ) ) {
		errors.addNew( "no initialisation block" , missingErrLoc );
	}
	if ( !errors.empty( ) ) {
		return;
	}

	calls.clear( );
	uint32_t cfi;
	for ( cfi = 0 ; cfi < root->nFunctions( ) ; cfi ++ ) {
		calls.next( );
		visitor.visit( root->function( cfi ) , [&]( A_Node& node , bool exit ) -> bool {
			if ( exit || dynamic_cast< A_ExpressionNode* >( &node ) ) {
				return false;
			}
			if ( node.type( ) != A_Node::OP_CALL ) {
				return true;
			}

			auto& call( (T_CallInstrNode&) node );
			const auto callee( root->functionIndex( call.id( ) ) );
			if ( callee >= 0 ) {
				if ( !calls.contains( cfi , callee ) ) {
					calls.add( (uint32_t) callee );
				}

				// Check argument count while we're at it
				auto& fn( (T_FuncNode&) root->function( callee ) );
				if ( fn.arguments( ) != call.arguments( ) ) {
					T_StringBuilder sb;
					sb << "function expects " << fn.arguments( )
						<< " argument" << ( fn.arguments( ) == 1 ? "" : "s" )
						<< ", " << call.arguments( )
						<< " argument" << ( call.arguments( ) == 1 ? "" : "s" )
						<< " provided";
					errors.addNew( std::move( sb ) , call.location( ) );
				}
			} else {
				errors.addNew( "unknown function" , call.idLocation( ) );
			}
			return false;
		} );
	}
	if ( !errors.empty( ) ) {
		return;
	}

	T_InstrRestriction callInfo[ calls.size( ) ];
	callGraphVisitor.visit( root->functionIndex( "*init*" ) ,
		[&]( uint32_t id , const bool exit ) -> bool {
			if ( exit || callInfo[ id ] & E_InstrRestriction::INIT ) {
				return false;
			}
			callInfo[ id ] |= E_InstrRestriction::INIT;
			return true;
		} );
	callGraphVisitor.visit( root->functionIndex( "*frame*" ) ,
		[&]( uint32_t id , const bool exit ) -> bool {
			if ( exit || callInfo[ id ] & E_InstrRestriction::FRAME ) {
				return false;
			}
			callInfo[ id ] |= E_InstrRestriction::FRAME;
			return true;
		} );
	for ( auto i = 0u ; i < root->nFunctions( ) ; i ++ ) {
		visitor.visit( root->function( i ) ,
			[&]( A_Node& node , bool exit ) {
				if ( exit ) {
					return false;
				}
				auto const* instr( dynamic_cast< A_InstructionNode const* >( &node ) );
				if ( instr && ( instr->restriction( ) & callInfo[ i ] ) ) {
					T_StringBuilder sb;
					sb << "instruction not allowed in "
						<< ( ( instr->restriction( ) & E_InstrRestriction::INIT )
							? "initialisation" : "frame function" );
					errors.addNew( std::move( sb ) , instr->location( ) );
				}
				return true;
			} );
	}
}

void T_ParserImpl_::parseFunction(
		T_SRDList const& funcList ) noexcept
{
	assert( funcList.size( ) != 0 );

	auto const& fw( funcList[ 0 ] );
	if ( fw.type( ) != E_SRDTokenType::WORD
			|| ( fw.stringValue( ) != "init" && fw.stringValue( ) != "frame"
				&& fw.stringValue( ) != "fn" ) ) {
		errors.addNew( "init, frame or fn expected" , fw.location( ) );
		return;
	}

	T_String const& ftw( fw.stringValue( ) );
	T_OwnPtr< A_FuncNode > fn;
	if ( ftw == "fn" ) {
		if ( funcList.size( ) < 3 ) {
			errors.addNew( "function name and arguments expected" ,
					fw.location( ) );
			return;
		}
		if ( funcList[ 1 ].type( ) != E_SRDTokenType::WORD ) {
			errors.addNew( "function name expected" , funcList[ 1 ].location( ) );
			return;
		}

		fn = NewOwned< T_FuncNode >( funcList[ 1 ].stringValue( ) , *root );
		parseFunctionArguments( dynamic_cast< T_FuncNode& >( *fn ) ,
				funcList[ 2 ] );
	} else {
		fn = NewOwned< T_SpecialFuncNode >( ftw == "init" , *root );
	}
	fn->location( ) = fw.location( );

	const auto af( root->addFunction( fn ) );
	if ( af.dupLocation ) {
		T_StringBuilder esb( "duplicate " );
		switch ( fn->type( ) ) {
			case A_Node::DECL_FN:
				esb << "function '" << fn->name( ) << "'";
				break;
			case A_Node::DECL_INIT:
				esb << "initialisation function";
				break;
			case A_Node::DECL_FRAME:
				esb << "frame function";
				break;
			default: std::abort( );
		}
		esb << "; previous declaration: " << *af.dupLocation;
		errors.addNew( std::move( esb ) , fw.location( ) );
	}

	parseInstructions( af.function.instructions( ) , funcList , ftw == "fn" ? 3 : 1 );
}

void T_ParserImpl_::parseFunctionArguments(
		T_FuncNode& function ,
		T_SRDToken const& argsToken ) noexcept
{
	if ( argsToken.type( ) != E_SRDTokenType::LIST ) {
		errors.addNew( "arguments list expected" , argsToken.location( ) );
		return;
	}
	for ( auto const& token : argsToken.list( ) ) {
		if ( token.type( ) != E_SRDTokenType::WORD ) {
			errors.addNew( "argument name expected" , token.location( ) );
			continue;
		}

		const auto rv( function.addArgument( token ) );
		if ( rv ) {
			T_StringBuilder esb;
			esb << "duplicate argument '" << token.stringValue( )
				<< "'; previous declaration: " << *rv;
			errors.addNew( std::move( esb ) , token.location( ) );
		}
	}
}

/*----------------------------------------------------------------------------*/

void T_ParserImpl_::parseInstructions(
		T_InstrListNode& instructions ,
		T_SRDList const& input ,
		const uint32_t start ) noexcept
{
	for ( auto iter( input.begin( ) + start ) ; iter.valid( ) ; iter ++ ) {
		T_SRDToken const& itok( *iter );
		if ( itok.type( ) != E_SRDTokenType::LIST ) {
			errors.addNew( "instruction expected" , itok.location( ) );
			continue;
		}

		T_SRDList const& ilist( itok.list( ) );
		if ( ilist.empty( ) ) {
			errors.addNew( "instruction expected" , itok.location( ) );
			continue;
		}

		T_SRDToken const& iname( ilist[ 0 ] );
		if ( iname.type( ) != E_SRDTokenType::WORD ) {
			errors.addNew( "instruction name expected" , iname.location( ) );
			continue;
		}

		T_String const& iword( iname.stringValue( ) );
		if ( !instrMap.contains( iword ) ) {
			errors.addNew( "unknown instruction" , iname.location( ) );
			continue;
		}

#define M_CASE_( NAME , FNAME ) case E_InstrType::NAME: parse##FNAME##Instruction( instructions , ilist ); break
		switch ( *instrMap.get( iword ) ) {
			M_CASE_( CALL , Call );
			M_CASE_( IF , If );
			M_CASE_( INPUT , Input );
			M_CASE_( PIPELINE , Pipeline );
			M_CASE_( PROFILE , Profile );
			M_CASE_( PROGRAM , Program );
			M_CASE_( SET , Set );
			M_CASE_( TEXTURE , Texture );
			M_CASE_( USE_FRAMEBUFFER , UseFramebuffer );
			M_CASE_( USE_PIPELINE , UsePipeline );
			M_CASE_( USE_PROGRAM , UseProgram );
			M_CASE_( USE_TEXTURE , UseTexture );
			M_CASE_( VIEWPORT , Viewport );

		    case E_InstrType::FULLSCREEN:
			instructions.add< T_FullscreenInstrNode >( ).location( ) = iname.location( );
			break;
		}
#undef M_CASE_
	}
}

P_InstrListNode T_ParserImpl_::parseBlock(
		A_Node& parent ,
		T_SRDToken const& block ) noexcept
{
	if ( block.type( ) != E_SRDTokenType::LIST ) {
		errors.addNew( "block expected" , block.location( ) );
		return {};
	}

	P_InstrListNode rv{ NewOwned< T_InstrListNode >( parent ) };
	rv->location( ) = block.location( );
	parseInstructions( *rv , block.list( ) , 0 );
	return rv;
}

/*----------------------------------------------------------------------------*/

#define M_INSTR_( NAME ) \
	void T_ParserImpl_::parse##NAME##Instruction( \
			T_InstrListNode& instructions , \
			T_SRDList const& input ) noexcept

M_INSTR_( Call )
{
	if ( input.size( ) == 1 || input[ 1 ].type( ) != E_SRDTokenType::WORD ) {
		errors.addNew( "function identifier expected" ,
				input[ input.size( ) == 1 ? 0 : 1 ].location( ) );
		return;
	}

	auto& instr{ instructions.add< T_CallInstrNode >( input[ 1 ] ) };
	instr.location( ) = input[ 0 ].location( );
	for ( auto it = input.begin( ) + 2 ; it.valid( ) ; ++it ) {
		instr.addArgument( parseExpression( instr , *it ) );
	}
}

/*----------------------------------------------------------------------------*/

M_INSTR_( If )
{
	if ( input.size( ) == 1 ) {
		errors.addNew( "expression and 'then' block expected" ,
				input[ 0 ].location( ) );
		return;
	}

	T_CondInstrNode& cond{ instructions.add< T_CondInstrNode >( ) };
	cond.location( ) = input[ 0 ].location( );
	cond.setExpression( parseExpression( cond , input[ 1 ] ) );

	if ( input.size( ) == 2 ) {
		errors.addNew( "'then' block expected" ,
				input[ 0 ].location( ) );
		return;
	}

	cond.setCase( 1 , parseBlock( cond , input[ 2 ] ) );
	if ( input.size( ) > 3 ) {
		cond.setDefaultCase( parseBlock( cond , input[ 3 ] ) );
		if ( input.size( ) > 4 ) {
			errors.addNew( "too many arguments" , input[ 4 ].location( ) );
		}
	}
}

/*----------------------------------------------------------------------------*/

M_INSTR_( Input )
{
	if ( input.size( ) < 2 || !input[ 1 ].isText( ) ) {
		errors.addNew( "input identifier expected" ,
				input[ input.size( ) < 2 ? 0 : 1 ].location( ) );
		return;
	}
	if ( input.size( ) > 3 ) {
		errors.addNew( "too many arguments" , input[ 3 ].location( ) );
	}
	if ( input.size( ) >= 3 && !input[ 2 ].isNumeric( ) ) {
		errors.addNew( "default value expected" , input[ 2 ].location( ) );
	}

	const bool hasDefault( input.size( ) >= 3 && input[ 2 ].isNumeric( ) );
	auto& instr( ([&]() -> T_InputInstrNode& {
		if ( hasDefault ) {
			return instructions.add< T_InputInstrNode >(
					input[ 1 ] , input[ 2 ] );
		}
		return instructions.add< T_InputInstrNode >( input[ 1 ] );
	})( ) );
	instr.location( ) = input[ 0 ].location( );
}

/*----------------------------------------------------------------------------*/

M_INSTR_( Pipeline )
{
	if ( input.size( ) < 3 ) {
		errors.addNew( "identifier and program identifiers expected" ,
				input[ 0 ].location( ) );
		return;
	}

	const bool validId( input[ 1 ].type( ) == E_SRDTokenType::WORD );
	if ( !validId ) {
		errors.addNew( "pipeline identifier expected" , input[ 1 ].location( ) );
	}

	T_PipelineInstrNode& pipeline{ ([&instructions,&input,validId]( ) -> T_PipelineInstrNode& {
		if ( validId ) {
			return instructions.add< T_PipelineInstrNode >( input[ 0 ] );
		}
		return instructions.add< T_PipelineInstrNode >( );
	})() };
	pipeline.location( ) = input[ 0 ].location( );

	const auto nMax{ std::min( input.size( ) , 8u ) };
	for ( auto i = 2u ; i < nMax ; i ++ ) {
		T_SRDToken const& tok( input[ i ] );
		if ( tok.type( ) != E_SRDTokenType::WORD ) {
			errors.addNew( "program identifier expected" ,
					tok.location( ) );
			continue;
		}
		const auto dup( pipeline.addProgram( tok ) );
		if ( dup ) {
			T_StringBuilder esb;
			esb << "duplicate program identifier; previous use: " << *dup;
			errors.addNew( std::move( esb ) , tok.location( ) );
		}
	}

	if ( input.size( ) > 8 ) {
		errors.addNew( "too many arguments" , input[ 8 ].location( ) );
	}
}

/*----------------------------------------------------------------------------*/

M_INSTR_( Profile )
{
	const bool hasEnough( input.size( ) < 2 );
	if ( hasEnough || !input[ 1 ].isText( ) ) {
		errors.addNew( "profiling section name expected" ,
				hasEnough ? input[ 1 ].location( ) : T_SRDLocation{} );
		if ( !hasEnough ) {
			return;
		}
	}

	const T_String text( input[ 1 ].isText( ) ? input[ 1 ].stringValue( ) : "*invalid*" );
	T_ProfileInstrNode& profile{ instructions.add< T_ProfileInstrNode >( text ) };
	profile.location( ) = input[ 0 ].location( );
	parseInstructions( profile.instructions( ) , input , 2 );
}

/*----------------------------------------------------------------------------*/

M_INSTR_( Program )
{
	bool ok{ true };
	if ( input.size( ) == 1 ) {
		errors.addNew( "identifier and program name required" ,
				input[ 0 ].location( ) );
		return;
	}
	if ( input[ 1 ].type( ) != E_SRDTokenType::WORD ) {
		errors.addNew( "identifier (word) expected" , input[ 1 ].location( ) );
		ok = false;
	}
	if ( input.size( ) == 2 ) {
		errors.addNew( "program name required" , input[ 0 ].location( ) );
		return;
	}
	if ( !input[ 2 ].isText( ) ) {
		errors.addNew( "program name (string or word) expected" ,
				input[ 2 ].location( ) );
		ok = false;
	}

	if ( input.size( ) > 3 ) {
		errors.addNew( "too many arguments" , input[ 3 ].location( ) );
	}
	if ( !ok ) {
		return;
	}

	T_ProgramInstrNode& program{ instructions.add< T_ProgramInstrNode >(
				input[ 1 ] , input[ 2 ] ) };
	program.location( ) = input[ 0 ].location( );
}

/*----------------------------------------------------------------------------*/

M_INSTR_( Set )
{
	bool ok{ true };
	if ( input.size( ) == 1 ) {
		errors.addNew( "identifier and expression required" ,
				input[ 0 ].location( ) );
		return;
	}
	if ( input[ 1 ].type( ) != E_SRDTokenType::WORD ) {
		errors.addNew( "variable identifier expected" , input[ 1 ].location( ) );
		ok = false;
	}
	if ( input.size( ) == 2 ) {
		errors.addNew( "expression required" , input[ 0 ].location( ) );
	}
	if ( input.size( ) > 3 ) {
		errors.addNew( "too many arguments" , input[ 3 ].location( ) );
	}
	if ( !ok ) {
		return;
	}

	T_SetInstrNode& set{ instructions.add< T_SetInstrNode >( input[ 1 ] ) };
	set.location( ) = input[ 0 ].location( );
	if ( input.size( ) > 2 ) {
		auto expr( parseExpression( set , input[ 2 ] ) );
		if ( expr ) {
			set.setExpression( std::move( expr ) );
		}
	}
}

/*----------------------------------------------------------------------------*/

M_INSTR_( Texture )
{
	if ( input.size( ) < 2 || input[ 1 ].type( ) != E_SRDTokenType::WORD ) {
		errors.addNew( "texture identifier expected" ,
				( input.size( ) < 2 ? input[ 0 ] : input[ 1 ] ).location( ) );
		return;
	}
	if ( input.size( ) < 3 || input[ 2 ].type( ) != E_SRDTokenType::WORD ) {
		errors.addNew( "texture type expected" ,
				( input.size( ) < 3 ? input[ 0 ] : input[ 2 ] ).location( ) );
		return;
	}

	auto const* const ttt( texTypeMap.get( input[ 2 ].stringValue( ) ) );
	if ( !ttt ) {
		errors.addNew( "invalid texture type" ,
				( input.size( ) < 3 ? input[ 0 ] : input[ 2 ] ).location( ) );
	}
	const auto tt( ttt ? *ttt : E_TexType::RGB8 );

	auto& instr{ instructions.add< T_TextureInstrNode >( input[ 1 ] , tt ) };
	instr.location( ) = input[ 0 ].location( );
	if ( input.size( ) > 4 ) {
		instr.setWidth( parseExpression( instr , input[ 3 ] ) );
	} else {
		errors.addNew( "width expected" , input[ 0 ].location( ) );
	}
	if ( input.size( ) > 4 ) {
		instr.setHeight( parseExpression( instr , input[ 3 ] ) );
	} else {
		errors.addNew( "height expected" , input[ 0 ].location( ) );
	}
	if ( input.size( ) > 5 ) {
		errors.addNew( "too many arguments" , input[ 5 ].location( ) );
	}
}

/*----------------------------------------------------------------------------*/

M_INSTR_( UseFramebuffer )
{
	parseUseCommon( instructions , input , T_UseInstrNode::FRAMEBUFFER );
}

M_INSTR_( UsePipeline )
{
	parseUseCommon( instructions , input , T_UseInstrNode::PIPELINE );
}

M_INSTR_( UseProgram )
{
	parseUseCommon( instructions , input , T_UseInstrNode::PROGRAM );
}

void T_ParserImpl_::parseUseCommon(
		T_InstrListNode& instructions ,
		T_SRDList const& input ,
		T_UseInstrNode::E_Type type ) noexcept
{
	if ( input.size( ) == 1 || input[ 1 ].type( ) != E_SRDTokenType::WORD ) {
		errors.addNew( "resource identifier expected" ,
				input[ input.size( ) == 1 ? 0 : 1 ].location( ) );
		return;
	}
	if ( input.size( ) > 2 ) {
		errors.addNew( "too many arguments" , input[ 2 ].location( ) );
	}

	auto& instr{ instructions.add< T_UseInstrNode >( type , input[ 1 ] ) };
	instr.location( ) = input[ 0 ].location( );
}

/*----------------------------------------------------------------------------*/

M_INSTR_( UseTexture )
{
	if ( input.size( ) == 1 || !input[ 1 ].isInteger( ) ) {
		errors.addNew( "bank number expected" ,
				input[ input.size( ) == 1 ? 0 : 1 ].location( ) );
		return;
	}
	if ( input[ 1 ].longValue( ) < 0 || input[ 1 ].longValue( ) > UINT32_MAX ) {
		errors.addNew( "invalid bank number" , input[ 1 ].location( ) );
		return;
	}

	if ( input.size( ) == 2 || input[ 2 ].type( ) != E_SRDTokenType::WORD ) {
		errors.addNew( "texture identifier expected" ,
				input[ input.size( ) == 2 ? 0 : 2 ].location( ) );
		return;
	}
	if ( input.size( ) == 3 || input[ 3 ].type( ) != E_SRDTokenType::WORD ) {
		errors.addNew( "sampler identifier expected" ,
				input[ input.size( ) == 3 ? 0 : 3 ].location( ) );
		return;
	}
	if ( input.size( ) > 4 ) {
		errors.addNew( "too many arguments" , input[ 4 ].location( ) );
	}

	auto& instr{ instructions.add< T_UseTextureInstrNode >(
			input[ 1 ] , input[ 2 ] , input[ 3 ] ) };
	instr.location( ) = input[ 0 ].location( );
}

/*----------------------------------------------------------------------------*/

M_INSTR_( Viewport )
{
	auto& instr{ instructions.add< T_ViewportInstrNode >( ) };
	instr.location( ) = input[ 0 ].location( );

	for ( auto i = 1u ; i < 5 ; i ++ ) {
		T_ViewportInstrNode::E_Parameter p{
			T_ViewportInstrNode::E_Parameter( i ) };
		if ( input.size( ) < i ) {
			T_StringBuilder sb;
			sb << "missing ";
			switch ( p ) {
			    case T_ViewportInstrNode::PX: sb << "X"; break;
			    case T_ViewportInstrNode::PY: sb << "Y"; break;
			    case T_ViewportInstrNode::PWIDTH: sb << "width"; break;
			    case T_ViewportInstrNode::PHEIGHT: sb << "height"; break;
			}
			sb << " parameter";
			errors.addNew( std::move( sb ) , input[ 0 ].location( ) );
			return;
		} else {
			instr.setParameter( p , parseExpression( instr , input[ i ] ) );
		}
	}
}

/*----------------------------------------------------------------------------*/

P_ExpressionNode T_ParserImpl_::parseExpression(
		A_Node& parent ,
		T_SRDToken const& token ) noexcept
{
	if ( token.isNumeric( ) ) {
		return NewOwned< T_ConstantExprNode >( parent , token );
	}
	if ( token.type( ) == E_SRDTokenType::WORD || token.type( ) == E_SRDTokenType::VAR ) {
		return NewOwned< T_IdentifierExprNode >( parent , token );
	}

	if ( token.type( ) == E_SRDTokenType::LIST && !token.list( ).empty( ) ) {
		return parseOperation( parent , token.list( ) );
	}

	errors.addNew( "invalid expression" , token.location( ) );
	return {};
}

P_ExpressionNode T_ParserImpl_::parseOperation(
		A_Node& parent ,
		T_SRDList const& opList ) noexcept
{
	T_SRDToken const& opId( opList[ 0 ] );
	if ( opId.type( ) != E_SRDTokenType::WORD ) {
		errors.addNew( "operator expected" , opId.location( ) );
		return {};
	}

	if ( opId.stringValue( ) == "get-input" ) {
		if ( opList.size( ) == 1 || !opList[ 1 ].isText( ) ) {
			errors.addNew( "input identifier expected" ,
					opList[ opList.size( ) == 1 ? 0 : 1 ].location( ) );
			return { };
		}
		if ( opList.size( ) > 2 ) {
			errors.addNew( "too many arguments" , opList[ 2 ].location( ) );
		}
		auto node{ NewOwned< T_InputExprNode >( parent , opList[ 1 ] ) };
		node->location( ) = opList[ 0 ].location( );
		return node;
	}

	if ( binOpMap.contains( opId.stringValue( ) ) ) {
		return parseBinOp( parent , opList ,
				*binOpMap.get( opId.stringValue( ) ) );
	}
	if ( unaryOpMap.contains( opId.stringValue( ) ) ) {
		return parseUnaryOp( parent , opList ,
				*unaryOpMap.get( opId.stringValue( ) ) );
	}

	errors.addNew( "unknown operator" , opId.location( ) );
	return {};
}

P_ExpressionNode T_ParserImpl_::parseBinOp(
		A_Node& parent ,
		T_SRDList const& opList ,
		T_BinaryOperatorNode::E_Operator op ) noexcept
{
	if ( opList.size( ) < 3 ) {
		errors.addNew( "not enough arguments" , opList[ 0 ].location( ) );
	} else if ( opList.size( ) > 3 ) {
		errors.addNew( "too many arguments" , opList[ 3 ].location( ) );
	}

	T_OwnPtr< T_BinaryOperatorNode > opNode{
		NewOwned< T_BinaryOperatorNode >( parent , op ) };
	opNode->location( ) = opList[ 0 ].location( );

	if ( opList.size( ) > 1 ) {
		auto left{ parseExpression( *opNode , opList[ 1 ] ) };
		if ( left ) {
			opNode->setLeft( std::move( left ) );
		}
	}
	if ( opList.size( ) > 2 ) {
		auto right{ parseExpression( *opNode , opList[ 2 ] ) };
		if ( right ) {
			opNode->setRight( std::move( right ) );
		}
	}

	return opNode;
}

P_ExpressionNode T_ParserImpl_::parseUnaryOp(
		A_Node& parent ,
		T_SRDList const& opList ,
		T_UnaryOperatorNode::E_Operator op ) noexcept
{
	if ( opList.size( ) < 2 ) {
		errors.addNew( "not enough arguments" , opList[ 0 ].location( ) );
	} else if ( opList.size( ) > 2 ) {
		errors.addNew( "too many arguments" , opList[ 2 ].location( ) );
	}

	T_OwnPtr< T_UnaryOperatorNode > opNode{
		NewOwned< T_UnaryOperatorNode >( parent , op ) };
	opNode->location( ) = opList[ 0 ].location( );

	if ( opList.size( ) > 1 ) {
		auto argument{ parseExpression( *opNode , opList[ 1 ] ) };
		if ( argument ) {
			opNode->setArgument( std::move( argument ) );
		}
	}

	return opNode;
}

} // namespace

/*----------------------------------------------------------------------------*/

T_Parser::T_Parser( ) noexcept
	: A_PrivateImplementation( new T_ParserImpl_( &errors_ , &rootNode_ ) ) ,
		errors_( 64 ) , rootNode_{}
{}

bool T_Parser::parse(
		T_SRDList const& input ) noexcept
{
	errors_.clear( );
	rootNode_ = NewOwned< T_RootNode >( );
	p< T_ParserImpl_ >( ).parseTopLevel( input );
	return errors_.empty( );
}