#ifndef STORM_UTILITY_PRISM_H_
#define STORM_UTILITY_PRISM_H_

#include <memory>
#include <boost/algorithm/string.hpp>

#include "src/storage/expressions/ExpressionManager.h"
#include "src/storage/prism/Program.h"
#include "src/utility/OsDetection.h"
#include "src/utility/macros.h"
#include "src/exceptions/InvalidArgumentException.h"

namespace storm {
    namespace utility {
        namespace prism {
            // A structure holding information about a particular choice.
            template<typename ValueType, typename KeyType=uint32_t, typename Compare=std::less<uint32_t>>
            struct Choice {
            public:
                Choice(uint_fast64_t actionIndex = 0, bool createChoiceLabels = false) : distribution(), actionIndex(actionIndex), choiceLabels(nullptr) {
                    if (createChoiceLabels) {
                        choiceLabels = std::shared_ptr<boost::container::flat_set<uint_fast64_t>>(new boost::container::flat_set<uint_fast64_t>());
                    }
                }
                
                Choice(Choice const& other) = default;
                Choice& operator=(Choice const& other) = default;
#ifndef WINDOWS
                Choice(Choice&& other) = default;
                Choice& operator=(Choice&& other) = default;
#endif
                
                /*!
                 * Returns an iterator to the first element of this choice.
                 *
                 * @return An iterator to the first element of this choice.
                 */
                typename std::map<KeyType, ValueType>::iterator begin() {
                    return distribution.begin();
                }
                
                /*!
                 * Returns an iterator to the first element of this choice.
                 *
                 * @return An iterator to the first element of this choice.
                 */
                typename std::map<KeyType, ValueType>::const_iterator begin() const {
                    return distribution.cbegin();
                }
                
                /*!
                 * Returns an iterator that points past the elements of this choice.
                 *
                 * @return An iterator that points past the elements of this choice.
                 */
                typename std::map<KeyType, ValueType>::iterator end() {
                    return distribution.end();
                }
                
                /*!
                 * Returns an iterator that points past the elements of this choice.
                 *
                 * @return An iterator that points past the elements of this choice.
                 */
                typename std::map<KeyType, ValueType>::const_iterator end() const {
                    return distribution.cend();
                }
                
                /*!
                 * Returns an iterator to the element with the given key, if there is one. Otherwise, the iterator points to
                 * distribution.end().
                 *
                 * @param value The value to find.
                 * @return An iterator to the element with the given key, if there is one.
                 */
                typename std::map<KeyType, ValueType>::iterator find(uint_fast64_t value) {
                    return distribution.find(value);
                }
                
                /*!
                 * Inserts the contents of this object to the given output stream.
                 *
                 * @param out The stream in which to insert the contents.
                 */
                friend std::ostream& operator<<(std::ostream& out, Choice<ValueType> const& choice) {
                    out << "<";
                    for (auto const& stateProbabilityPair : choice.distribution) {
                        out << stateProbabilityPair.first << " : " << stateProbabilityPair.second << ", ";
                    }
                    out << ">";
                    return out;
                }
                
                /*!
                 * Adds the given label to the labels associated with this choice.
                 *
                 * @param label The label to associate with this choice.
                 */
                void addChoiceLabel(uint_fast64_t label) {
                    choiceLabels->insert(label);
                }
                
                /*!
                 * Adds the given label set to the labels associated with this choice.
                 *
                 * @param labelSet The label set to associate with this choice.
                 */
                void addChoiceLabels(boost::container::flat_set<uint_fast64_t> const& labelSet) {
                    for (uint_fast64_t label : labelSet) {
                        addChoiceLabel(label);
                    }
                }
                
                /*!
                 * Retrieves the set of labels associated with this choice.
                 *
                 * @return The set of labels associated with this choice.
                 */
                boost::container::flat_set<uint_fast64_t> const& getChoiceLabels() const {
                    return *choiceLabels;
                }
                
                /*!
                 * Retrieves the index of the action of this choice.
                 *
                 * @return The index of the action of this choice.
                 */
                uint_fast64_t getActionIndex() const {
                    return actionIndex;
                }
                
                /*!
                 * Retrieves the entry in the choice that is associated with the given state and creates one if none exists,
                 * yet.
                 *
                 * @param state The state for which to add the entry.
                 * @return A reference to the entry that is associated with the given state.
                 */
                ValueType& getOrAddEntry(uint_fast64_t state) {
                    auto stateProbabilityPair = distribution.find(state);
                    
                    if (stateProbabilityPair == distribution.end()) {
                        distribution[state] = ValueType();
                    }
                    return distribution.at(state);
                }
                
                /*!
                 * Retrieves the entry in the choice that is associated with the given state and creates one if none exists,
                 * yet.
                 *
                 * @param state The state for which to add the entry.
                 * @return A reference to the entry that is associated with the given state.
                 */
                ValueType const& getOrAddEntry(uint_fast64_t state) const {
                    auto stateProbabilityPair = distribution.find(state);
                    
                    if (stateProbabilityPair == distribution.end()) {
                        distribution[state] = ValueType();
                    }
                    return distribution.at(state);
                }
                
                void addProbability(KeyType state, ValueType value) {
                    distribution[state] += value;
                }
                
            private:
                // The distribution that is associated with the choice.
                std::map<KeyType, ValueType, Compare> distribution;
                
                // The index of the action name.
                uint_fast64_t actionIndex;
                
                // The labels that are associated with this choice.
                std::shared_ptr<boost::container::flat_set<uint_fast64_t>> choiceLabels;
            };
            
            static std::map<storm::expressions::Variable, storm::expressions::Expression> parseConstantDefinitionString(storm::prism::Program const& program, std::string const& constantDefinitionString) {
                std::map<storm::expressions::Variable, storm::expressions::Expression> constantDefinitions;
                std::set<storm::expressions::Variable> definedConstants;
                
                if (!constantDefinitionString.empty()) {
                    // Parse the string that defines the undefined constants of the model and make sure that it contains exactly
                    // one value for each undefined constant of the model.
                    std::vector<std::string> definitions;
                    boost::split(definitions, constantDefinitionString, boost::is_any_of(","));
                    for (auto& definition : definitions) {
                        boost::trim(definition);
                        
                        // Check whether the token could be a legal constant definition.
                        uint_fast64_t positionOfAssignmentOperator = definition.find('=');
                        if (positionOfAssignmentOperator == std::string::npos) {
                            throw storm::exceptions::InvalidArgumentException() << "Illegal constant definition string: syntax error.";
                        }
                        
                        // Now extract the variable name and the value from the string.
                        std::string constantName = definition.substr(0, positionOfAssignmentOperator);
                        boost::trim(constantName);
                        std::string value = definition.substr(positionOfAssignmentOperator + 1);
                        boost::trim(value);
                        
                        // Check whether the constant is a legal undefined constant of the program and if so, of what type it is.
                        if (program.hasConstant(constantName)) {
                            // Get the actual constant and check whether it's in fact undefined.
                            auto const& constant = program.getConstant(constantName);
                            storm::expressions::Variable variable = constant.getExpressionVariable();
                            STORM_LOG_THROW(!constant.isDefined(), storm::exceptions::InvalidArgumentException, "Illegally trying to define already defined constant '" << constantName <<"'.");
                            STORM_LOG_THROW(definedConstants.find(variable) == definedConstants.end(), storm::exceptions::InvalidArgumentException, "Illegally trying to define constant '" << constantName <<"' twice.");
                            definedConstants.insert(variable);
                            
                            if (constant.getType().isBooleanType()) {
                                if (value == "true") {
                                    constantDefinitions[variable] = program.getManager().boolean(true);
                                } else if (value == "false") {
                                    constantDefinitions[variable] = program.getManager().boolean(false);
                                } else {
                                    throw storm::exceptions::InvalidArgumentException() << "Illegal value for boolean constant: " << value << ".";
                                }
                            } else if (constant.getType().isIntegerType()) {
                                int_fast64_t integerValue = std::stoi(value);
                                constantDefinitions[variable] = program.getManager().integer(integerValue);
                            } else if (constant.getType().isRationalType()) {
                                double doubleValue = std::stod(value);
                                constantDefinitions[variable] = program.getManager().rational(doubleValue);
                            }
                        } else {
                            STORM_LOG_THROW(false, storm::exceptions::InvalidArgumentException, "Illegal constant definition string: unknown undefined constant " << constantName << ".");
                        }
                    }
                }
                
                return constantDefinitions;
            }
        } // namespace prism
    } // namespace utility
} // namespace storm

#endif /* STORM_UTILITY_PRISM_H_ */