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

#define INVASIVE_TRACES

using namespace ebcl;
using namespace ops;
using namespace opast;

namespace {

struct T_CompilerImpl_
{
	T_Visitor< A_Node > astVisitor{ ASTVisitorBrowser };
	T_Set< uint32_t > constants{ UseTag< IndexBacked< > >( ) };

	T_ParserOutput* input;
	P_OpProgram output;

	uint32_t fiVariables , fiFramebuffers ,
		 fiPipelines , fiPrograms ,
		 fiSamplers , fiTextures;

	P_OpProgram compile(
			T_ParserOutput const& input ) noexcept;

    private:
	void gatherConstants( ) noexcept;
	void countAssets( ) noexcept;

	bool compileNode( uint32_t funcIndex ,
			A_Node& node ,
			bool exit ) noexcept;
};


P_OpProgram T_CompilerImpl_::compile(
		T_ParserOutput const& in ) noexcept
{
	input = const_cast< T_ParserOutput* >( &in );
	output = NewOwned< T_OpProgram >( );

	// Gather all constants used in expressions, count resources
	gatherConstants( );
	countAssets( );

	// Get function indices
	// FIXME ideally we should remap functions so that init is always 0
	// and frame is always 1
	output->init = input->root.functionIndex( "*init*" );
	output->frame = input->root.functionIndex( "*frame*" );
#ifdef INVASIVE_TRACES
	printf( "function indices\n\t%d\tinit\n\t%d\tframe\n" ,
			output->init , output->frame );
#endif

	// Compile each function
	uint32_t cfi;
	for ( cfi = 0u ; cfi < input->root.nFunctions( ) ; cfi ++ ) {
		output->ops.next( );
		auto& func( input->root.function( cfi ) );
#ifdef INVASIVE_TRACES
		printf( "compiling function %s\n" ,
				func.name( ).toOSString( ).data( ) );
#endif
		astVisitor.visit( func ,
			[=]( A_Node& node , const bool exit ) -> bool {
				return compileNode( cfi , node , exit );
			} );
	}

	return std::move( output );
}

void T_CompilerImpl_::gatherConstants( ) noexcept
{
	constants.clear( );
	astVisitor.visit( input->root , [&]( A_Node& node , const bool exit ) {
		if ( exit && node.type( ) == A_Node::EXPR_CONST ) {
			T_OpValue value;
			value.f = dynamic_cast< T_ConstantExprNode& >( node ).floatValue( );
			if ( value.f != 0 && value.f != 1 ) {
				constants.add( value.u );
			}
		}
		return true;
	} );

#ifdef INVASIVE_TRACES
	printf( "%d constants\n" , constants.size( ) );
	for ( auto i = 0u ; i < constants.size( ) ; i ++ ) {
		printf( "    %08x" , constants[ i ] );
		if ( i % 4 == 3 ) {
			printf( "\n" );
		}
	}
	if ( constants.size( ) % 4 ) {
		printf( "\n" );
	}
#endif
}

void T_CompilerImpl_::countAssets( ) noexcept
{
	auto const nt{ input->types.size( ) };
	for ( auto i = 0u ; i < nt ; i ++ ) {
		const auto t{ input->types.values( )[ i ] };
		switch ( t ) {
		    case E_DataType::FRAMEBUFFER:
			output->nFramebuffers ++;
			break;
		    case E_DataType::PIPELINE:
			output->nPipelines ++;
			break;
		    case E_DataType::PROGRAM:
			output->nPrograms ++;
			break;
		    case E_DataType::SAMPLER:
			output->nSamplers ++;
			break;
		    case E_DataType::TEXTURE:
			output->nTextures ++;
			break;
		    case E_DataType::VARIABLE:
			output->nVariables ++;
			break;

		    case E_DataType::INPUT:
			assert( !output->inputs.contains(
						input->types.keys( )[ i ] ) );
			output->inputs.add( input->types.keys( )[ i ] );
			break;

		    case E_DataType::BUILTIN:
		    case E_DataType::UNKNOWN:
			break;
		}
	}

	fiVariables = 3 + constants.size( );
	fiFramebuffers = fiVariables + output->nVariables;
	fiPipelines = fiFramebuffers + output->nFramebuffers;
	fiPrograms = fiPipelines + output->nPipelines;
	fiSamplers = fiPrograms + output->nPrograms;
	fiTextures = fiSamplers + output->nSamplers;

#ifdef INVASIVE_TRACES
	printf( "assets\n\t%d framebuffers\n\t%d pipelines\n"
			"\t%d programs\n\t%d samplers\n\t%d textures\n"
			"\t%d variables\n\t%d inputs\n" ,
		output->nFramebuffers , output->nPipelines ,
		output->nPrograms , output->nSamplers ,
		output->nTextures , output->nVariables ,
		output->inputs.size( ) );
	printf( "table ranges\n\t0\t2\tBuilt-ins\n"
			"\t3\t%d\tConstants\n"
			"\t%d\t%d\tVariables\n"
			"\t%d\t%d\tFramebuffers\n"
			"\t%d\t%d\tPipelines\n"
			"\t%d\t%d\tPrograms\n"
			"\t%d\t%d\tSamplers\n"
			"\t%d\t%d\tTextures\n" ,
		fiVariables - 1 , fiVariables , fiFramebuffers - 1 , fiFramebuffers ,
		fiPipelines - 1 , fiPipelines , fiPrograms - 1 , fiPrograms ,
		fiSamplers - 1 , fiSamplers , fiTextures - 1 , fiTextures ,
		fiTextures + output->nTextures - 1 );
#endif
}

bool T_CompilerImpl_::compileNode(
		const uint32_t funcIndex ,
		A_Node& node ,
		const bool exit ) noexcept
{
	return false;
}

}


/*= T_Compiler =================================================================*/

T_Compiler::T_Compiler( ) noexcept
	: A_PrivateImplementation( new T_CompilerImpl_( ) )
{ }

P_OpProgram T_Compiler::compile(
		T_ParserOutput const& input ) noexcept
{
	return p< T_CompilerImpl_ >( ).compile( input );
}