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

using namespace ebcl;
using namespace opast;

namespace {

/*============================================================================*/


void PrintStreamError(
		char const* const prefix ,
		T_String const& name ,
		X_StreamError const& error )
{
	T_StringBuilder sb;
	sb << prefix << " '" << name << "': " << error.what( );
	if ( error.code( ) == E_StreamError::SYSTEM_ERROR ) {
		sb << " (error code " << error.systemError( ) << ")";
	}
	sb << '\n' << '\0';
	fprintf( stderr , "%s" , sb.data( ) );
}

void WriteSRDError(
		T_StringBuilder& sb ,
		T_SRDError const& error )
{
	sb << error.location( ) << " - " << error.error( ) << "\n";
}


/*============================================================================*/
// FIXME TESTING, MOVE THIS LATER

A_Node* OpASTBrowser(
		A_Node& node ,
		const uint32_t child )
{
	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::OP_PROGRAM: case A_Node::OP_PIPELINE:
	    case A_Node::OP_INPUT:
		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;
	    }

	}
	return nullptr;
}


bool checkCalls( T_RootNode& root )
{
	T_Visitor< A_Node > visitor( OpASTBrowser );
	T_Array< T_SRDError > errors;

	T_MultiArray< uint32_t > calls;
	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( ) ) {
		T_StringBuilder sb;
		for ( auto const& err : errors ) {
			WriteSRDError( sb , err );
		}
		sb << "Parser failed\n" << '\0';
		fprintf( stderr , "%s" , sb.data( ) );
		return false;
	}

	T_Visitor< uint32_t , uint32_t > callGraphVisitor(
			[&]( 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_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;
			} );
	}

	if ( !errors.empty( ) ) {
		T_StringBuilder sb;
		for ( auto const& err : errors ) {
			WriteSRDError( sb , err );
		}
		sb << "Parser failed\n" << '\0';
		fprintf( stderr , "%s" , sb.data( ) );
		return false;
	}

	T_StringBuilder sb;
	for ( auto callerId = 0u ; callerId < calls.size( ) ; callerId ++ ) {
		const auto nCallees( calls.sizeOf( callerId ) );
		if ( !nCallees ) {
			continue;
		}
		sb << root.function( callerId ).name( ) << " calls";
		for ( auto i = 0u ; i < nCallees ; i ++ ) {
			auto const& callee( root.function( calls.get( callerId , i ) ) );
			sb << ' ' << callee.name( );

		}
		sb << '\n';
	}
	sb << '\0';
	printf( "%s" , sb.data( ) );

	return true;
}

/*============================================================================*/

} // namespace

int main( int argc , char** argv )
{
	// Open file
	const T_String inputName( argc >= 2 ? argv[ 1 ] : "demo.srd" );
	T_File input( inputName , E_FileMode::READ_ONLY );
	try {
		input.open( );
	} catch ( X_StreamError const& e ) {
		PrintStreamError( "Could not open" , inputName , e );
		return 1;
	}

	// Load SRD data
	T_SRDMemoryTarget srdOut;
	srdOut.clearComments( true ).clearFlushToken( true );
	try {
		T_SRDTextReader srdReader{ srdOut };
		T_FileInputStream fis{ input };
		srdReader.read( inputName , fis );
	} catch ( X_StreamError const& e ) {
		PrintStreamError( "Could not open" , inputName , e );
		return 1;
	} catch ( X_SRDErrors const& e ) {
		T_StringBuilder sb;
		const auto nErrors( e.errors.size( ) );
		for ( auto i = 0u ; i < nErrors ; i ++ ) {
			WriteSRDError( sb , e.errors[ i ] );
		}
		sb << "No parsing happened due to format errors\n" << '\0';
		fprintf( stderr , "%s" , sb.data( ) );
		return 2;
	}

	// Parse the fuck
	T_Parser parser;
	if ( parser.parse( srdOut.list( ) ) ) {
		printf( "Success!\n" );

		auto result( parser.result( ) );
		checkCalls( *result );
		return 0;
	} else {
		T_StringBuilder sb;
		for ( auto const& err : parser.errors( ) ) {
			WriteSRDError( sb , err );
		}
		sb << "Parser failed\n" << '\0';
		fprintf( stderr , "%s" , sb.data( ) );
		return 3;
	}
}