//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// TypeSubstitution.cc --
//
// Author           : Richard C. Bilson
// Created On       : Mon May 18 07:44:20 2015
// Last Modified By : Rob Schluntz
// Last Modified On : Tue Apr 26 11:15:29 2016
// Update Count     : 3
//

#include "Type.h"
#include "TypeSubstitution.h"

TypeSubstitution::TypeSubstitution() {
}

TypeSubstitution::TypeSubstitution( const TypeSubstitution &other ) {
	initialize( other, *this );
}

TypeSubstitution::~TypeSubstitution() {
	for ( TypeEnvType::iterator i = typeEnv.begin(); i != typeEnv.end(); ++i ) {
		delete( i->second );
	}
	for ( VarEnvType::iterator i = varEnv.begin(); i != varEnv.end(); ++i ) {
		delete( i->second );
	}
}

TypeSubstitution &TypeSubstitution::operator=( const TypeSubstitution &other ) {
	if ( this == &other ) return *this;
	initialize( other, *this );
	return *this;
}

void TypeSubstitution::initialize( const TypeSubstitution &src, TypeSubstitution &dest ) {
	dest.typeEnv.clear();
	dest.varEnv.clear();
	dest.add( src );
}

void TypeSubstitution::add( const TypeSubstitution &other ) {
	for ( TypeEnvType::const_iterator i = other.typeEnv.begin(); i != other.typeEnv.end(); ++i ) {
		typeEnv[ i->first ] = i->second->clone();
	} // for
	for ( VarEnvType::const_iterator i = other.varEnv.begin(); i != other.varEnv.end(); ++i ) {
		varEnv[ i->first ] = i->second->clone();
	} // for
}

void TypeSubstitution::add( std::string formalType, Type *actualType ) {
	TypeEnvType::iterator i = typeEnv.find( formalType );
	if ( i != typeEnv.end() ) {
		delete i->second;
	} // if
	typeEnv[ formalType ] = actualType->clone();
}

void TypeSubstitution::remove( std::string formalType ) {
	TypeEnvType::iterator i = typeEnv.find( formalType );
	if ( i != typeEnv.end() ) {
		delete i->second;
		typeEnv.erase( formalType );
	} // if
}

Type *TypeSubstitution::lookup( std::string formalType ) const {
	TypeEnvType::const_iterator i = typeEnv.find( formalType );
	
	// break on not in substitution set
	if ( i == typeEnv.end() ) return 0;
	
	// attempt to transitively follow TypeInstType links.
	while ( TypeInstType *actualType = dynamic_cast< TypeInstType* >( i->second ) ) {
		const std::string& typeName = actualType->get_name();
		
		// break cycles in the transitive follow
		if ( formalType == typeName ) break;
		
		// Look for the type this maps to, returning previous mapping if none-such
		i = typeEnv.find( typeName );
		if ( i == typeEnv.end() ) return actualType;
	}
	
	// return type from substitution set
	return i->second;
	
#if 0
	if ( i == typeEnv.end() ) {
		return 0;
	} else {
		return i->second;
	} // if
#endif
}

bool TypeSubstitution::empty() const {
	return typeEnv.empty() && varEnv.empty();
}

void TypeSubstitution::normalize() {
	do {
		subCount = 0;
		freeOnly = true;
		for ( TypeEnvType::iterator i = typeEnv.begin(); i != typeEnv.end(); ++i ) {
			i->second = i->second->acceptMutator( *this );
		}
	} while ( subCount );
}

Type * TypeSubstitution::mutate( TypeInstType *inst ) {
	BoundVarsType::const_iterator bound = boundVars.find( inst->get_name() );
	if ( bound != boundVars.end() ) return inst;

	TypeEnvType::const_iterator i = typeEnv.find( inst->get_name() );
	if ( i == typeEnv.end() ) {
		return inst;
	} else {
///	    std::cout << "found " << inst->get_name() << ", replacing with ";
///	    i->second->print( std::cout );
///	    std::cout << std::endl;
		subCount++;
		Type *newtype = i->second->clone();
		newtype->get_qualifiers() += inst->get_qualifiers();
		delete inst;
		return newtype;
	} // if
}

Expression * TypeSubstitution::mutate( NameExpr *nameExpr ) {
	VarEnvType::const_iterator i = varEnv.find( nameExpr->get_name() );
	if ( i == varEnv.end() ) {
		return nameExpr;
	} else {
		subCount++;
		delete nameExpr;
		return i->second->clone();
	} // if
}

template< typename TypeClass >
Type *TypeSubstitution::handleType( TypeClass *type ) {
	BoundVarsType oldBoundVars( boundVars );
	// bind type variables from forall-qualifiers
	if ( freeOnly ) {
		for ( std::list< TypeDecl* >::const_iterator tyvar = type->get_forall().begin(); tyvar != type->get_forall().end(); ++tyvar ) {
			boundVars.insert( (*tyvar )->get_name() );
		} // for
	} // if
	Type *ret = Mutator::mutate( type );
	boundVars = oldBoundVars;
	return ret;
}

template< typename TypeClass >
Type *TypeSubstitution::handleAggregateType( TypeClass *type ) {
	BoundVarsType oldBoundVars( boundVars );
	// bind type variables from forall-qualifiers
	if ( freeOnly ) {
		for ( std::list< TypeDecl* >::const_iterator tyvar = type->get_forall().begin(); tyvar != type->get_forall().end(); ++tyvar ) {
			boundVars.insert( (*tyvar )->get_name() );
		} // for
	} // if
	// bind type variables from generic type instantiations
	std::list< TypeDecl* > *baseParameters = type->get_baseParameters();
	if ( baseParameters && ! type->get_parameters().empty() ) {
		for ( std::list< TypeDecl* >::const_iterator tyvar = baseParameters->begin(); tyvar != baseParameters->end(); ++tyvar ) {
			boundVars.insert( (*tyvar)->get_name() );
		} // for
	} // if
	Type *ret = Mutator::mutate( type );
	boundVars = oldBoundVars;
	return ret;
}

Type * TypeSubstitution::mutate( VoidType *basicType ) {
	return handleType( basicType );
}

Type * TypeSubstitution::mutate( BasicType *basicType ) {
	return handleType( basicType );
}

Type * TypeSubstitution::mutate( PointerType *pointerType ) {
	return handleType( pointerType );
}

Type * TypeSubstitution::mutate( ArrayType *arrayType ) {
	return handleType( arrayType );
}

Type * TypeSubstitution::mutate( FunctionType *functionType ) {
	return handleType( functionType );
}

Type * TypeSubstitution::mutate( StructInstType *aggregateUseType ) {
	return handleAggregateType( aggregateUseType );
}

Type * TypeSubstitution::mutate( UnionInstType *aggregateUseType ) {
	return handleAggregateType( aggregateUseType );
}

Type * TypeSubstitution::mutate( EnumInstType *aggregateUseType ) {
	return handleType( aggregateUseType );
}

Type * TypeSubstitution::mutate( TraitInstType *aggregateUseType ) {
	return handleType( aggregateUseType );
}

Type * TypeSubstitution::mutate( TupleType *tupleType ) {
	return handleType( tupleType );
}

Type * TypeSubstitution::mutate( VarArgsType *varArgsType ) {
	return handleType( varArgsType );
}

void TypeSubstitution::print( std::ostream &os, int indent ) const {
	os << std::string( indent, ' ' ) << "Types:" << std::endl;
	for ( TypeEnvType::const_iterator i = typeEnv.begin(); i != typeEnv.end(); ++i ) {
		os << std::string( indent+2, ' ' ) << i->first << " -> ";
		i->second->print( os, indent+4 );
		os << std::endl;
	} // for
	os << std::string( indent, ' ' ) << "Non-types:" << std::endl;
	for ( VarEnvType::const_iterator i = varEnv.begin(); i != varEnv.end(); ++i ) {
		os << std::string( indent+2, ' ' ) << i->first << " -> ";
		i->second->print( os, indent+4 );
		os << std::endl;
	} // for
}

std::ostream & operator<<( std::ostream & out, const TypeSubstitution & sub ) {
	sub.print( out );
	return out;
}


// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //