// ******************** flopc++ **********************************************
// File: MP_expression.cpp
// $Id$
// Author: Tim Helge Hultberg (thh@mat.ua.pt)
// Copyright (C) 2003 Tim Helge Hultberg
// All Rights Reserved.
//****************************************************************************

#include <sstream>
#include "MP_expression.hpp"
#include "MP_constant.hpp"
#include "MP_boolean.hpp"
#include "MP_constraint.hpp"
#include "MP_set.hpp"
#include "MP_variable.hpp"

namespace flopc {

class Expression_constant : public TerminalExpression {
    friend class MP_expression;

private:
    Expression_constant(const Constant& c) : C(c) {}
    double level() const { 
	return C->evaluate(); 
    }
    double getValue() const {
	return C->evaluate();
    }
    int getColumn() const {
	return -1;
    }
    void generate(const MP_domain& domain,
		  vector<Constant> multiplicators,
		  GenerateFunctor& f,
		  double m) const {
	f.setMultiplicator(multiplicators,m);
	f.setTerminalExpression(this);
	domain.Forall(&f);
    }
    void insertVariables(set<MP_variable*>& v) const {}

    Constant C;
};

class Expression_plus : public Expression_operator {
    friend MP_expression operator+(const MP_expression& e1, const MP_expression& e2);
    friend MP_expression operator+(const MP_expression& e1, const Constant& e2);
    friend MP_expression operator+(const Constant& e1, const MP_expression& e2);	
private:
    Expression_plus(const MP_expression& e1, const MP_expression& e2) : 
	Expression_operator(e1,e2) {}
    double level() const { 
	return left->level()+right->level(); 
    }
    void generate(const MP_domain& domain,
		  vector<Constant> multiplicators,
		  GenerateFunctor& f,
		  double m) const { 
	left->generate(domain, multiplicators,f,m);
	right->generate(domain, multiplicators,f,m);
    }
};

class Expression_minus : public Expression_operator {
    friend MP_expression operator-(const MP_expression& e1, const MP_expression& e2);
    friend MP_expression operator-(const MP_expression& e1, const Constant& e2); 
    friend MP_expression operator-(const Constant& e1, const MP_expression& e2);
private:
    Expression_minus(const MP_expression& e1, const MP_expression& e2) : 
	Expression_operator(e1,e2) {}
    double level() const { 
	return left->level()-right->level(); 
    }
    void generate(const MP_domain& domain,
		  vector<Constant> multiplicators,
		  GenerateFunctor& f,
		  double m) const {
	left->generate(domain, multiplicators,f,m);
	right->generate(domain, multiplicators,f,-m);
    }
};

class Expression_mult : public MP_expression_base {
    friend MP_expression operator*(const Constant& e1, const MP_expression& e2); 
    friend MP_expression operator*(const MP_expression& e1, const Constant& e2);

private:
    Expression_mult(const Constant& e1, const MP_expression& e2) : 
	left(e1), right(e2) {}
    double level() const { 
	return left->evaluate()*right->level(); 
    }
    void generate(const MP_domain& domain,
		  vector<Constant> multiplicators,
		  GenerateFunctor& f,
		  double m) const {
	multiplicators.push_back(left);
	right->generate(domain, multiplicators, f, m);
    }
    void insertVariables(set<MP_variable*>& v) const {
	right->insertVariables(v);
    }
    Constant left;
    MP_expression right;
};

class Expression_sum : public MP_expression_base, public Functor {
    friend MP_expression sum(const MP_domain& d, const MP_expression& e);
private:
    Expression_sum(const MP_domain& d, const MP_expression& e) : 
	D(d), exp(e) {}
    void operator()() const {
	the_sum += exp->level();
    }
    double level() const {
	the_sum = 0;
	D.Forall(this);
	return the_sum;
    } 
    void generate(const MP_domain& domain,
		  vector<Constant> multiplicators,
		  GenerateFunctor& f,
		  double m) const {
	// The order, D*domain (NOT domain*D), is important for efficiency! 
	exp->generate(D*domain, multiplicators, f, m); 
    }
    void insertVariables(set<MP_variable*>& v) const {
	exp->insertVariables(v);
    }

    mutable double the_sum;
    MP_domain D;
    MP_expression exp;
};


MP_expression operator+(const MP_expression& e1, const MP_expression& e2) {
    return new Expression_plus(e1, e2);
}
MP_expression operator+(const MP_expression& e1, const Constant& e2) {
    return new Expression_plus(e1, e2);
}
MP_expression operator+(const Constant& e1, const MP_expression& e2) {
    return new Expression_plus(e1, e2);
}

MP_expression operator-(const MP_expression& e1, 
			const MP_expression& e2) {
    return new Expression_minus(e1, e2);
}
MP_expression operator-(const MP_expression& e1, 
			const Constant& e2) {
    return new Expression_minus(e1, e2);
}
MP_expression operator-(const Constant& e1, 
			const MP_expression& e2) {
    return new Expression_minus(e1, e2);
}

MP_expression operator*(const Constant& e1, const MP_expression& e2) {
    return new Expression_mult(e1, e2);
}
MP_expression operator*(const MP_expression& e1, const Constant& e2) {
	return new Expression_mult(e2, e1);
}

MP_expression sum(const MP_domain& d, const MP_expression& e) {
    return new Expression_sum(d, e);  
}
    
} // End of namespace flopc

using namespace flopc;


MP_expression::MP_expression(const Constant &c) :
    Handle<MP_expression_base*>(new Expression_constant(c)) {} 

MP_expression::MP_expression(const VariableRef &v) : 
    Handle<MP_expression_base*>(const_cast<VariableRef*>(&v)) {} 

int GenerateFunctor::row_number() const {
    return R->row_number();
}

void GenerateFunctor::operator()() const {
    double multiplicator = m_;
    for (unsigned int i=0; i<multiplicators.size(); i++) {
	multiplicator *= multiplicators[i]->evaluate();
    }
    int colNumber = C->getColumn();
    if ( colNumber != outOfBound ) {
	double val = multiplicator*C->getValue();
	if (val != 0) {
	    Coefs.push_back(Coef(colNumber, row_number(), val));
	}
    }
}