//
// 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.
//
// TypeEnvironment.cc --
//
// Author           : Richard C. Bilson
// Created On       : Sun May 17 12:19:47 2015
// Last Modified By : Peter A. Buhr
// Last Modified On : Sun May 17 12:23:36 2015
// Update Count     : 3
//

#include <cassert>                     // for assert
#include <algorithm>                   // for copy, set_intersection
#include <iterator>                    // for ostream_iterator, insert_iterator
#include <utility>                     // for pair, move

#include "Common/utility.h"            // for maybeClone
#include "SynTree/Type.h"              // for Type, FunctionType, Type::Fora...
#include "SynTree/TypeSubstitution.h"  // for TypeSubstitution
#include "TypeEnvironment.h"

namespace ResolvExpr {
	void printAssertionSet( const AssertionSet &assertions, std::ostream &os, int indent ) {
		for ( AssertionSet::const_iterator i = assertions.begin(); i != assertions.end(); ++i ) {
			i->first->print( os, indent );
			if ( i->second.isUsed ) {
				os << "(used)";
			} else {
				os << "(not used)";
			} // if
		} // for
	}

	void printOpenVarSet( const OpenVarSet &openVars, std::ostream &os, int indent ) {
		os << std::string( indent, ' ' );
		for ( OpenVarSet::const_iterator i = openVars.begin(); i != openVars.end(); ++i ) {
			os << i->first << "(" << i->second << ") ";
		} // for
	}

	void EqvClass::initialize( const EqvClass &src, EqvClass &dest ) {
		initialize( src, dest, src.type );
	}

	void EqvClass::initialize( const EqvClass &src, EqvClass &dest, const Type *ty ) {
		dest.vars = src.vars;
		dest.type = maybeClone( ty );
		dest.allowWidening = src.allowWidening;
		dest.data = src.data;
	}

	EqvClass::EqvClass() : type( nullptr ), allowWidening( true ) {
	}

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

	EqvClass::EqvClass( const EqvClass &other, const Type *ty ) {
		initialize( other, *this, ty );
	}

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

	EqvClass::~EqvClass() {
		delete type;
	}

	void EqvClass::print( std::ostream &os, Indenter indent ) const {
		os << "( ";
		std::copy( vars.begin(), vars.end(), std::ostream_iterator< std::string >( os, " " ) );
		os << ")";
		if ( type ) {
			os << " -> ";
			type->print( os, indent+1 );
		} // if
		if ( ! allowWidening ) {
			os << " (no widening)";
		} // if
		os << std::endl;
	}

	const EqvClass* TypeEnvironment::lookup( const std::string &var ) const {
		for ( std::list< EqvClass >::const_iterator i = env.begin(); i != env.end(); ++i ) {
			if ( i->vars.find( var ) != i->vars.end() ) {
///       std::cout << var << " is in class ";
///       i->print( std::cout );
				return &*i;
			}
///     std::cout << var << " is not in class ";
///     i->print( std::cout );
		} // for
		return nullptr;
	}

	/// Removes any class from env that intersects eqvClass
	void filterOverlappingClasses( std::list<EqvClass> &env, const EqvClass &eqvClass ) {
		for ( auto i = env.begin(); i != env.end(); ) {
			auto next = i;
			++next;
			std::set<std::string> intersection;
			std::set_intersection( i->vars.begin(), i->vars.end(), eqvClass.vars.begin(), eqvClass.vars.end(), 
				std::inserter( intersection, intersection.begin() ) );
			if ( ! intersection.empty() ) { env.erase( i ); }
			i = next;
		}
	}

	void TypeEnvironment::add( const EqvClass &eqvClass ) {
		filterOverlappingClasses( env, eqvClass );
		env.push_back( eqvClass );
	}

	void TypeEnvironment::add( EqvClass &&eqvClass ) {
		filterOverlappingClasses( env, eqvClass );
		env.push_back( std::move(eqvClass) );
	}

	void TypeEnvironment::add( const Type::ForallList &tyDecls ) {
		for ( Type::ForallList::const_iterator i = tyDecls.begin(); i != tyDecls.end(); ++i ) {
			EqvClass newClass;
			newClass.vars.insert( (*i)->get_name() );
			newClass.data = TypeDecl::Data{ (*i) };
			env.push_back( newClass );
		} // for
	}

	void TypeEnvironment::add( const TypeSubstitution & sub ) {
		EqvClass newClass;
		for ( auto p : sub ) {
			newClass.vars.insert( p.first );
			newClass.type = p.second->clone();
			newClass.allowWidening = false;
			// Minimal assumptions. Not technically correct, but might be good enough, and
			// is the best we can do at the moment since information is lost in the
			// transition to TypeSubstitution
			newClass.data = TypeDecl::Data{ TypeDecl::Dtype, false };
			add( newClass );
		}
	}

	void TypeEnvironment::makeSubstitution( TypeSubstitution &sub ) const {
		for ( std::list< EqvClass >::const_iterator theClass = env.begin(); theClass != env.end(); ++theClass ) {
			for ( std::set< std::string >::const_iterator theVar = theClass->vars.begin(); theVar != theClass->vars.end(); ++theVar ) {
///       std::cerr << "adding " << *theVar;
				if ( theClass->type ) {
///         std::cerr << " bound to ";
///         theClass->type->print( std::cerr );
///         std::cerr << std::endl;
					sub.add( *theVar, theClass->type );
				} else if ( theVar != theClass->vars.begin() ) {
					TypeInstType *newTypeInst = new TypeInstType( Type::Qualifiers(), *theClass->vars.begin(), theClass->data.kind == TypeDecl::Ftype );
///         std::cerr << " bound to variable " << *theClass->vars.begin() << std::endl;
					sub.add( *theVar, newTypeInst );
					delete newTypeInst;
				} // if
			} // for
		} // for
///   std::cerr << "input env is:" << std::endl;
///   print( std::cerr, 8 );
///   std::cerr << "sub is:" << std::endl;
///   sub.print( std::cerr, 8 );
		sub.normalize();
	}

	void TypeEnvironment::print( std::ostream &os, Indenter indent ) const {
		for ( const EqvClass & theClass : env ) {
			theClass.print( os, indent );
		} // for
	}

	std::list< EqvClass >::iterator TypeEnvironment::internal_lookup( const std::string &var ) {
		for ( std::list< EqvClass >::iterator i = env.begin(); i != env.end(); ++i ) {
			if ( i->vars.find( var ) == i->vars.end() ) {
				return i;
			} // if
		} // for
		return env.end();
	}

	void TypeEnvironment::simpleCombine( const TypeEnvironment &second ) {
		env.insert( env.end(), second.env.begin(), second.env.end() );
	}

	void TypeEnvironment::combine( const TypeEnvironment &second, Type *(*combineFunc)( Type*, Type* ) ) {
		TypeEnvironment secondCopy( second );
		for ( std::list< EqvClass >::iterator firstClass = env.begin(); firstClass != env.end(); ++firstClass ) {
			EqvClass &newClass = *firstClass;
			std::set< std::string > newVars;
			for ( std::set< std::string >::const_iterator var = firstClass->vars.begin(); var != firstClass->vars.end(); ++var ) {
				std::list< EqvClass >::iterator secondClass = secondCopy.internal_lookup( *var );
				if ( secondClass != secondCopy.env.end() ) {
					newVars.insert( secondClass->vars.begin(), secondClass->vars.end() );
					if ( secondClass->type ) {
						if ( newClass.type ) {
							Type *newType = combineFunc( newClass.type, secondClass->type );
							delete newClass.type;
							newClass.type = newType;
							newClass.allowWidening = newClass.allowWidening && secondClass->allowWidening;
						} else {
							newClass.type = secondClass->type->clone();
							newClass.allowWidening = secondClass->allowWidening;
						} // if
					} // if
					secondCopy.env.erase( secondClass );
				} // if
			} // for
			newClass.vars.insert( newVars.begin(), newVars.end() );
		} // for
		for ( std::list< EqvClass >::iterator secondClass = secondCopy.env.begin(); secondClass != secondCopy.env.end(); ++secondClass ) {
			env.push_back( *secondClass );
		} // for
	}

	void TypeEnvironment::extractOpenVars( OpenVarSet &openVars ) const {
		for ( std::list< EqvClass >::const_iterator eqvClass = env.begin(); eqvClass != env.end(); ++eqvClass ) {
			for ( std::set< std::string >::const_iterator var = eqvClass->vars.begin(); var != eqvClass->vars.end(); ++var ) {
				openVars[ *var ] = eqvClass->data;
			} // for
		} // for
	}

	void TypeEnvironment::addActual( const TypeEnvironment& actualEnv, OpenVarSet& openVars ) {
		for ( const EqvClass& c : actualEnv ) {
			EqvClass c2 = c;
			c2.allowWidening = false;
			for ( const std::string& var : c2.vars ) {
				openVars[ var ] = c2.data;
			}
			env.push_back( std::move(c2) );
		}
	}

	std::ostream & operator<<( std::ostream & out, const TypeEnvironment & env ) {
		env.print( out );
		return out;
	}
} // namespace ResolvExpr

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