#include "src/solver/GlpkLpSolver.h"

#ifdef STORM_HAVE_GLPK

#include <iostream>

#include "src/exceptions/InvalidStateException.h"
#include "src/settings/Settings.h"

#include "log4cplus/logger.h"
#include "log4cplus/loggingmacros.h"

extern log4cplus::Logger logger;

namespace storm {
    namespace solver {
        GlpkLpSolver::GlpkLpSolver(std::string const& name, ModelSense const& modelSense) : LpSolver(modelSense), lp(nullptr), nextVariableIndex(1), nextConstraintIndex(1), isOptimal(false), rowIndices(), columnIndices(), coefficientValues() {
            // Create the LP problem for glpk.
            lp = glp_create_prob();
            
            // Set its name and model sense.
            glp_set_prob_name(lp, name.c_str());
            this->setModelSense(modelSense);
            
            // Because glpk uses 1-based indexing (wtf!?), we need to put dummy elements into the matrix vectors.
            rowIndices.push_back(0);
            columnIndices.push_back(0);
            coefficientValues.push_back(0);
        }
        
        GlpkLpSolver::GlpkLpSolver(std::string const& name) : GlpkLpSolver(name, MINIMIZE) {
            // Intentionally left empty.
        }
        
        GlpkLpSolver::~GlpkLpSolver() {
            glp_delete_prob(this->lp);
            glp_free_env();
        }
        
        uint_fast64_t GlpkLpSolver::createContinuousVariable(std::string const& name, VariableType const& variableType, double lowerBound, double upperBound, double objectiveFunctionCoefficient) {
            glp_add_cols(this->lp, 1);
            glp_set_col_name(this->lp, nextVariableIndex, name.c_str());
            switch (variableType) {
                case LpSolver::BOUNDED:
                    glp_set_col_bnds(lp, nextVariableIndex, GLP_DB, lowerBound, upperBound);
                    break;
                case LpSolver::UNBOUNDED:
                    glp_set_col_bnds(lp, nextVariableIndex, GLP_FR, 0, 0);
                    break;
                case LpSolver::UPPER_BOUND:
                    glp_set_col_bnds(lp, nextVariableIndex, GLP_UP, 0, upperBound);
                    break;
                case LpSolver::LOWER_BOUND:
                    glp_set_col_bnds(lp, nextVariableIndex, GLP_LO, lowerBound, 0);
                    break;
            }
            glp_set_col_kind(this->lp, nextVariableIndex, GLP_CV);
            glp_set_obj_coef(this->lp, nextVariableIndex, objectiveFunctionCoefficient);
            ++nextVariableIndex;
            
            this->isOptimal = false;
            
            return nextVariableIndex - 1;
        }
        
        uint_fast64_t GlpkLpSolver::createIntegerVariable(std::string const& name, VariableType const& variableType, double lowerBound, double upperBound, double objectiveFunctionCoefficient) {
            uint_fast64_t index = this->createContinuousVariable(name, variableType, lowerBound, upperBound, objectiveFunctionCoefficient);
            glp_set_col_kind(this->lp, index, GLP_IV);
            return index;
        }
        
        uint_fast64_t GlpkLpSolver::createBinaryVariable(std::string const& name, double objectiveFunctionCoefficient) {
            uint_fast64_t index = this->createContinuousVariable(name, UNBOUNDED, 0, 1, objectiveFunctionCoefficient);
            glp_set_col_kind(this->lp, index, GLP_BV);
            return index;
        }
        
        void GlpkLpSolver::addConstraint(std::string const& name, std::vector<uint_fast64_t> const& variables, std::vector<double> const& coefficients, BoundType const& boundType, double rightHandSideValue) {
            if (variables.size() != coefficients.size()) {
                LOG4CPLUS_ERROR(logger, "Sizes of variable indices vector and coefficients vector do not match.");
                throw storm::exceptions::InvalidStateException() << "Sizes of variable indices vector and coefficients vector do not match.";
            }

            // Add the row that will represent this constraint.
            glp_add_rows(this->lp, 1);
            glp_set_row_name(this->lp, nextConstraintIndex, name.c_str());
            
            // Determine the type of the constraint and add it properly.
            bool isUpperBound = boundType == LESS || boundType == LESS_EQUAL;
            bool isStrict = boundType == LESS || boundType == GREATER;
            switch (boundType) {
                case LESS:
                    glp_set_row_bnds(this->lp, nextConstraintIndex, GLP_UP, 0, rightHandSideValue - storm::settings::Settings::getInstance()->getOptionByLongName("precision").getArgument(0).getValueAsDouble());
                    break;
                case LESS_EQUAL:
                    glp_set_row_bnds(this->lp, nextConstraintIndex, GLP_UP, 0, rightHandSideValue);
                    break;
                case GREATER:
                    glp_set_row_bnds(this->lp, nextConstraintIndex, GLP_LO, rightHandSideValue + storm::settings::Settings::getInstance()->getOptionByLongName("precision").getArgument(0).getValueAsDouble(), 0);
                    break;
                case GREATER_EQUAL:
                    glp_set_row_bnds(this->lp, nextConstraintIndex, GLP_LO, rightHandSideValue, 0);
                    break;
                case EQUAL:
                    glp_set_row_bnds(this->lp, nextConstraintIndex, GLP_FX, rightHandSideValue, rightHandSideValue);
                    break;
            }
            
            // Record the variables and coefficients in the coefficient matrix.
            rowIndices.insert(rowIndices.end(), variables.size(), nextConstraintIndex);
            columnIndices.insert(columnIndices.end(), variables.begin(), variables.end());
            coefficientValues.insert(coefficientValues.end(), coefficients.begin(), coefficients.end());
            
            ++nextConstraintIndex;
            this->isOptimal = false;
        }
        
        void GlpkLpSolver::setModelSense(ModelSense const& newModelSense) {
            glp_set_obj_dir(this->lp, newModelSense == MINIMIZE ? GLP_MIN : GLP_MAX);
            this->isOptimal = false;
        }
        
        void GlpkLpSolver::optimize() const {
            glp_load_matrix(this->lp, rowIndices.size() - 1, rowIndices.data(), columnIndices.data(), coefficientValues.data());
            int error = glp_simplex(this->lp, nullptr);
            
            if (error != 0) {
                LOG4CPLUS_ERROR(logger, "Unable to optimize glpk model (" << error << ").");
                throw storm::exceptions::InvalidStateException() << "Unable to optimize glpk model (" << error << ").";
            }
            
            this->isOptimal = true;
        }
        
        int_fast64_t GlpkLpSolver::getIntegerValue(uint_fast64_t variableIndex) const {
            double value = glp_get_col_prim(this->lp, static_cast<int>(variableIndex));
            
            if (std::abs(value - static_cast<int>(value)) <= storm::settings::Settings::getInstance()->getOptionByLongName("precision").getArgument(0).getValueAsDouble()) {
                // Nothing to do in this case.
            } else if (std::abs(value) > storm::settings::Settings::getInstance()->getOptionByLongName("precision").getArgument(0).getValueAsDouble()) {
                LOG4CPLUS_ERROR(logger, "Illegal value for integer variable in glpk solution (" << value << ").");
                throw storm::exceptions::InvalidStateException() << "Illegal value for integer variable in glpk solution (" << value << ").";
            }
            
            return static_cast<int_fast64_t>(value);
        }
        
        bool GlpkLpSolver::getBinaryValue(uint_fast64_t variableIndex) const {
            double value = glp_get_col_prim(this->lp, static_cast<int>(variableIndex));

            if (std::abs(value - 1) <= storm::settings::Settings::getInstance()->getOptionByLongName("precision").getArgument(0).getValueAsDouble()) {
                // Nothing to do in this case.
            } else if (std::abs(value) > storm::settings::Settings::getInstance()->getOptionByLongName("precision").getArgument(0).getValueAsDouble()) {
                LOG4CPLUS_ERROR(logger, "Illegal value for binary variable in Gurobi solution (" << value << ").");
                throw storm::exceptions::InvalidStateException() << "Illegal value for binary variable in Gurobi solution (" << value << ").";
            }
            
            return static_cast<bool>(value);
        }
        
        double GlpkLpSolver::getContinuousValue(uint_fast64_t variableIndex) const {
            return glp_get_col_prim(this->lp, static_cast<int>(variableIndex));
        }
        
        void GlpkLpSolver::writeModelToFile(std::string const& filename) const {
            glp_load_matrix(this->lp, rowIndices.size() - 1, rowIndices.data(), columnIndices.data(), coefficientValues.data());
            glp_write_lp(this->lp, 0, filename.c_str());
        }
    }
}

#endif