#ifndef STORM_ADAPTERS_Z3EXPRESSIONADAPTER_H_
#define STORM_ADAPTERS_Z3EXPRESSIONADAPTER_H_

#include <unordered_map>

// Include the headers of Z3 only if it is available.
#ifdef STORM_HAVE_Z3
#include "z3++.h"
#include "z3.h"
#endif

#include "storm-config.h"
#include "src/storage/expressions/Expressions.h"
#include "src/storage/expressions/ExpressionManager.h"
#include "src/utility/macros.h"
#include "src/exceptions/ExpressionEvaluationException.h"
#include "src/exceptions/InvalidTypeException.h"
#include "src/exceptions/NotImplementedException.h"

namespace storm {
    namespace adapters {

#ifdef STORM_HAVE_Z3
        class Z3ExpressionAdapter : public storm::expressions::ExpressionVisitor {
        public:
            /*!
             * Creates an expression adapter that can translate expressions to the format of Z3.
			 *
             * @param manager The manager that can be used to build expressions.
             * @param context A reference to the Z3 context over which to build the expressions. The lifetime of the
             * context needs to be guaranteed as long as the instance of this adapter is used.
             */
            Z3ExpressionAdapter(storm::expressions::ExpressionManager& manager, z3::context& context) : manager(manager), context(context), additionalAssertions(), variableToExpressionMapping() {
                // Here, we need to create the mapping from all variables known to the manager to their z3 counterparts.
                for (auto const& variableTypePair : manager) {
                    z3::expr z3Variable(context);
                    if (variableTypePair.second.isBooleanType()) {
                        z3Variable = context.bool_const(variableTypePair.first.getName().c_str());
                    } else if (variableTypePair.second.isUnboundedIntegralType()) {
                        z3Variable = context.int_const(variableTypePair.first.getName().c_str());
                    } else if (variableTypePair.second.isBoundedIntegralType()) {
                        z3Variable = context.bv_const(variableTypePair.first.getName().c_str(), variableTypePair.second.getWidth());
                    } else if (variableTypePair.second.isRationalType()) {
                        z3Variable = context.real_const(variableTypePair.first.getName().c_str());
                    } else {
                        STORM_LOG_THROW(false, storm::exceptions::InvalidTypeException, "Encountered variable '" << variableTypePair.first.getName() << "' with unknown type while trying to create solver variables.");
                    }
                    variableToExpressionMapping.insert(std::make_pair(variableTypePair.first, z3Variable));
                    declarationToVariableMapping.insert(std::make_pair(z3Variable.decl(), variableTypePair.first));
                }
            }
            
            /*!
             * Translates the given expression to an equivalent expression for Z3.
			 *
             * @param expression The expression to translate.
             * @return An equivalent expression for Z3.
             */
            z3::expr translateExpression(storm::expressions::Expression const& expression) {
                z3::expr result = boost::any_cast<z3::expr>(expression.getBaseExpression().accept(*this));

                for (z3::expr const& assertion : additionalAssertions) {
                    result = result && assertion;
                }
                additionalAssertions.clear();

                return result;
            }
            
            /*!
             * Translates the given variable to an equivalent expression for Z3.
             *
             * @param variable The variable to translate.
             * @return An equivalent expression for Z3.
             */
            z3::expr translateExpression(storm::expressions::Variable const& variable) {
                auto const& variableExpressionPair = variableToExpressionMapping.find(variable);
                STORM_LOG_ASSERT(variableExpressionPair != variableToExpressionMapping.end(), "Unable to find variable.");
                return variableExpressionPair->second;
            }
            
            /*!
             * Finds the counterpart to the given z3 variable declaration.
             *
             * @param z3Declaration The declaration for which to find the equivalent.
             * @return The equivalent counterpart.
             */
            storm::expressions::Variable const& getVariable(z3::func_decl z3Declaration) {
                auto const& declarationVariablePair = declarationToVariableMapping.find(z3Declaration);
                STORM_LOG_ASSERT(declarationVariablePair != declarationToVariableMapping.end(), "Unable to find declaration.");
                return declarationVariablePair->second;
            }
            
			storm::expressions::Expression translateExpression(z3::expr const& expr) {
				if (expr.is_app()) {
					switch (expr.decl().decl_kind()) {
						case Z3_OP_TRUE:
							return manager.boolean(true);
						case Z3_OP_FALSE:
							return manager.boolean(false);
						case Z3_OP_EQ:
							return this->translateExpression(expr.arg(0)) == this->translateExpression(expr.arg(1));
						case Z3_OP_ITE:
							return this->translateExpression(expr.arg(0)).ite(this->translateExpression(expr.arg(1)), this->translateExpression(expr.arg(2)));
						case Z3_OP_AND: {
							unsigned args = expr.num_args();
							STORM_LOG_THROW(args != 0, storm::exceptions::ExpressionEvaluationException, "Failed to convert Z3 expression. 0-ary AND is assumed to be an error.");
							if (args == 1) {
								return this->translateExpression(expr.arg(0));
							} else {
								storm::expressions::Expression retVal = this->translateExpression(expr.arg(0));
								for (unsigned i = 1; i < args; i++) {
									retVal = retVal && this->translateExpression(expr.arg(i));
								}
								return retVal;
							}
						}
						case Z3_OP_OR: {
							unsigned args = expr.num_args();
							STORM_LOG_THROW(args != 0, storm::exceptions::ExpressionEvaluationException, "Failed to convert Z3 expression. 0-ary OR is assumed to be an error.");
							if (args == 1) {
								return this->translateExpression(expr.arg(0));
							} else {
								storm::expressions::Expression retVal = this->translateExpression(expr.arg(0));
								for (unsigned i = 1; i < args; i++) {
									retVal = retVal || this->translateExpression(expr.arg(i));
								}
								return retVal;
							}
						}
						case Z3_OP_IFF:
							return this->translateExpression(expr.arg(0)).iff(this->translateExpression(expr.arg(1)));
						case Z3_OP_XOR:
							return this->translateExpression(expr.arg(0)) ^ this->translateExpression(expr.arg(1));
						case Z3_OP_NOT:
							return !this->translateExpression(expr.arg(0));
						case Z3_OP_IMPLIES:
							return this->translateExpression(expr.arg(0)).implies(this->translateExpression(expr.arg(1)));
						case Z3_OP_LE:
							return this->translateExpression(expr.arg(0)) <= this->translateExpression(expr.arg(1));
						case Z3_OP_GE:
							return this->translateExpression(expr.arg(0)) >= this->translateExpression(expr.arg(1));
						case Z3_OP_LT:
							return this->translateExpression(expr.arg(0)) < this->translateExpression(expr.arg(1));
						case Z3_OP_GT:
							return this->translateExpression(expr.arg(0)) > this->translateExpression(expr.arg(1));
						case Z3_OP_ADD:
							return this->translateExpression(expr.arg(0)) + this->translateExpression(expr.arg(1));
						case Z3_OP_SUB:
							return this->translateExpression(expr.arg(0)) - this->translateExpression(expr.arg(1));
						case Z3_OP_UMINUS:
							return -this->translateExpression(expr.arg(0));
						case Z3_OP_MUL:
							return this->translateExpression(expr.arg(0)) * this->translateExpression(expr.arg(1));
						case Z3_OP_DIV:
							return this->translateExpression(expr.arg(0)) / this->translateExpression(expr.arg(1));
						case Z3_OP_IDIV:
							return this->translateExpression(expr.arg(0)) / this->translateExpression(expr.arg(1));
						case Z3_OP_ANUM:
							// Arithmetic numeral.
							if (expr.is_int() && expr.is_const()) {
								long long value;
								if (Z3_get_numeral_int64(expr.ctx(), expr, &value)) {
									return manager.integer(value);
								} else {
									STORM_LOG_THROW(false, storm::exceptions::ExpressionEvaluationException, "Failed to convert Z3 expression. Expression is constant integer and value does not fit into 64-bit integer.");
								}
							} else if (expr.is_real() && expr.is_const()) {
								long long num;
								long long den;
								if (Z3_get_numeral_rational_int64(expr.ctx(), expr, &num, &den)) {
									return manager.rational(static_cast<double>(num) / static_cast<double>(den));
								} else {
									STORM_LOG_THROW(false, storm::exceptions::ExpressionEvaluationException, "Failed to convert Z3 expression. Expression is constant real and value does not fit into a fraction with 64-bit integer numerator and denominator.");
								}
							}
						case Z3_OP_UNINTERPRETED:
							// Currently, we only support uninterpreted constant functions.
							STORM_LOG_THROW(expr.is_const(), storm::exceptions::ExpressionEvaluationException, "Failed to convert Z3 expression. Encountered non-constant uninterpreted function.");
                            return manager.getVariable(expr.decl().name().str()).getExpression();
						default:
							STORM_LOG_THROW(false, storm::exceptions::ExpressionEvaluationException, "Failed to convert Z3 expression. Encountered unhandled Z3_decl_kind " << expr.decl().kind() <<".");
							break;
					}
				} else {
					STORM_LOG_THROW(false, storm::exceptions::ExpressionEvaluationException, "Failed to convert Z3 expression. Encountered unknown expression type.");
				}
			}

            virtual boost::any visit(storm::expressions::BinaryBooleanFunctionExpression const& expression) override {
                z3::expr leftResult = boost::any_cast<z3::expr>(expression.getFirstOperand()->accept(*this));
                z3::expr rightResult = boost::any_cast<z3::expr>(expression.getSecondOperand()->accept(*this));
                
                switch(expression.getOperatorType()) {
					case storm::expressions::BinaryBooleanFunctionExpression::OperatorType::And:
                        return leftResult && rightResult;
					case storm::expressions::BinaryBooleanFunctionExpression::OperatorType::Or:
                        return leftResult || rightResult;
					case storm::expressions::BinaryBooleanFunctionExpression::OperatorType::Xor:
						return z3::expr(context, Z3_mk_xor(context, leftResult, rightResult));
					case storm::expressions::BinaryBooleanFunctionExpression::OperatorType::Implies:
						return z3::expr(context, Z3_mk_implies(context, leftResult, rightResult));
					case storm::expressions::BinaryBooleanFunctionExpression::OperatorType::Iff:
						return z3::expr(context, Z3_mk_iff(context, leftResult, rightResult));
                    default:
                        STORM_LOG_THROW(false, storm::exceptions::ExpressionEvaluationException, "Cannot evaluate expression: unknown boolean binary operator '" << static_cast<int>(expression.getOperatorType()) << "' in expression " << expression << ".");
                }
                
            }
            
			virtual boost::any visit(storm::expressions::BinaryNumericalFunctionExpression const& expression) override {
                z3::expr leftResult = boost::any_cast<z3::expr>(expression.getFirstOperand()->accept(*this));
                z3::expr rightResult = boost::any_cast<z3::expr>(expression.getSecondOperand()->accept(*this));
        
                switch(expression.getOperatorType()) {
					case storm::expressions::BinaryNumericalFunctionExpression::OperatorType::Plus:
                        return leftResult + rightResult;
					case storm::expressions::BinaryNumericalFunctionExpression::OperatorType::Minus:
                        return leftResult - rightResult;
					case storm::expressions::BinaryNumericalFunctionExpression::OperatorType::Times:
                        return leftResult * rightResult;
					case storm::expressions::BinaryNumericalFunctionExpression::OperatorType::Divide:
                        return leftResult / rightResult;
					case storm::expressions::BinaryNumericalFunctionExpression::OperatorType::Min:
                        return ite(leftResult <= rightResult, leftResult, rightResult);
					case storm::expressions::BinaryNumericalFunctionExpression::OperatorType::Max:
                        return ite(leftResult >= rightResult, leftResult, rightResult);
                    default:
                        STORM_LOG_THROW(false, storm::exceptions::ExpressionEvaluationException, "Cannot evaluate expression: unknown numerical binary operator '" << static_cast<int>(expression.getOperatorType()) << "' in expression " << expression << ".");
                }
            }
            
			virtual boost::any visit(storm::expressions::BinaryRelationExpression const& expression) override {
                z3::expr leftResult = boost::any_cast<z3::expr>(expression.getFirstOperand()->accept(*this));
                z3::expr rightResult = boost::any_cast<z3::expr>(expression.getSecondOperand()->accept(*this));
    
                switch(expression.getRelationType()) {
					case storm::expressions::BinaryRelationExpression::RelationType::Equal:
                        return leftResult == rightResult;
					case storm::expressions::BinaryRelationExpression::RelationType::NotEqual:
                        return leftResult != rightResult;
					case storm::expressions::BinaryRelationExpression::RelationType::Less:
                        return leftResult < rightResult;
					case storm::expressions::BinaryRelationExpression::RelationType::LessOrEqual:
                        return leftResult <= rightResult;
					case storm::expressions::BinaryRelationExpression::RelationType::Greater:
                        return leftResult > rightResult;
					case storm::expressions::BinaryRelationExpression::RelationType::GreaterOrEqual:
                        return leftResult >= rightResult;
                    default:
                        STORM_LOG_THROW(false, storm::exceptions::ExpressionEvaluationException, "Cannot evaluate expression: unknown boolean binary operator '" << static_cast<int>(expression.getRelationType()) << "' in expression " << expression << ".");
                }    
            }
            
			virtual boost::any visit(storm::expressions::BooleanLiteralExpression const& expression) override {
                return context.bool_val(expression.getValue());
            }
            
			virtual boost::any visit(storm::expressions::DoubleLiteralExpression const& expression) override {
                std::stringstream fractionStream;
                fractionStream << expression.getValue();
                return context.real_val(fractionStream.str().c_str());
            }
            
			virtual boost::any visit(storm::expressions::IntegerLiteralExpression const& expression) override {
                return context.int_val(static_cast<int>(expression.getValue()));
            }
            
			virtual boost::any visit(storm::expressions::UnaryBooleanFunctionExpression const& expression) override {
                z3::expr childResult = boost::any_cast<z3::expr>(expression.getOperand()->accept(*this));
                
                switch (expression.getOperatorType()) {
					case storm::expressions::UnaryBooleanFunctionExpression::OperatorType::Not:
                        return !childResult;
                    default:
                        STORM_LOG_THROW(false, storm::exceptions::ExpressionEvaluationException, "Cannot evaluate expression: unknown boolean binary operator '" << static_cast<int>(expression.getOperatorType()) << "' in expression " << expression << ".");
                }    
            }
            
			virtual boost::any visit(storm::expressions::UnaryNumericalFunctionExpression const& expression) override {
                z3::expr childResult = boost::any_cast<z3::expr>(expression.getOperand()->accept(*this));
                
                switch(expression.getOperatorType()) {
					case storm::expressions::UnaryNumericalFunctionExpression::OperatorType::Minus:
                        return 0 - childResult;
					case storm::expressions::UnaryNumericalFunctionExpression::OperatorType::Floor: {
                        storm::expressions::Variable freshAuxiliaryVariable = manager.declareFreshAuxiliaryVariable(manager.getIntegerType());
                        z3::expr floorVariable = context.int_const(freshAuxiliaryVariable.getName().c_str());
						additionalAssertions.push_back(z3::expr(context, Z3_mk_int2real(context, floorVariable)) <= childResult && childResult < (z3::expr(context, Z3_mk_int2real(context, floorVariable)) + 1));
						return floorVariable;
					}
					case storm::expressions::UnaryNumericalFunctionExpression::OperatorType::Ceil:{
                        storm::expressions::Variable freshAuxiliaryVariable = manager.declareFreshAuxiliaryVariable(manager.getIntegerType());
                        z3::expr ceilVariable = context.int_const(freshAuxiliaryVariable.getName().c_str());
						additionalAssertions.push_back(z3::expr(context, Z3_mk_int2real(context, ceilVariable)) - 1 <= childResult && childResult < z3::expr(context, Z3_mk_int2real(context, ceilVariable)));
						return ceilVariable;
					}
                    default: STORM_LOG_THROW(false, storm::exceptions::ExpressionEvaluationException, "Cannot evaluate expression: unknown numerical unary operator '" << static_cast<int>(expression.getOperatorType()) << "'.");
                }
            }

			virtual boost::any visit(storm::expressions::IfThenElseExpression const& expression) override {
                z3::expr conditionResult = boost::any_cast<z3::expr>(expression.getCondition()->accept(*this));
                z3::expr thenResult = boost::any_cast<z3::expr>(expression.getThenExpression()->accept(*this));
                z3::expr elseResult = boost::any_cast<z3::expr>(expression.getElseExpression()->accept(*this));
				return z3::expr(context, Z3_mk_ite(context, conditionResult, thenResult, elseResult));
			}
            
			virtual boost::any visit(storm::expressions::VariableExpression const& expression) override {
                return variableToExpressionMapping.at(expression.getVariable());
            }

        private:
            // The manager that can be used to build expressions.
            storm::expressions::ExpressionManager& manager;

            // The context that is used to translate the expressions.
            z3::context& context;

            // A vector of assertions that need to be kept separate, because they were only implicitly part of an
            // assertion that was added.
			std::vector<z3::expr> additionalAssertions;

            // A mapping from variables to their Z3 equivalent.
            std::unordered_map<storm::expressions::Variable, z3::expr> variableToExpressionMapping;

            // A mapping from z3 declarations to the corresponding variables.
            std::unordered_map<Z3_func_decl, storm::expressions::Variable> declarationToVariableMapping;
        };
#endif
    } // namespace adapters
} // namespace storm

#endif /* STORM_ADAPTERS_Z3EXPRESSIONADAPTER_H_ */