/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */

/*
 *  Main authors:
 *     Guido Tack <guido.tack@monash.edu>
 */

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef __MINIZINC_SOLVER_HH__
#define __MINIZINC_SOLVER_HH__

#include <minizinc/exception.hh>
#include <minizinc/flattener.hh>
#include <minizinc/solver_config.hh>
#include <minizinc/solver_instance_base.hh>

#include <iostream>
#include <memory>
#include <string>
#include <vector>

namespace MiniZinc {

class SolverInitialiser {
public:
  SolverInitialiser(void);
};

class SolverFactory;

/// SolverRegistry is a storage for all SolverFactories in linked modules
class SolverRegistry {
public:
  void addSolverFactory(SolverFactory*);
  void removeSolverFactory(SolverFactory*);
  typedef std::vector<SolverFactory*> SFStorage;
  const SFStorage& getSolverFactories() const { return sfstorage; }

private:
  SFStorage sfstorage;
};  // SolverRegistry

/// this function returns the global SolverRegistry object
SolverRegistry* getGlobalSolverRegistry();

/// Representation of flags that can be passed to solvers
class MZNFZNSolverFlag {
public:
  /// The type of the solver flag
  enum FlagType { FT_ARG, FT_NOARG } t;
  /// The name of the solver flag
  std::string n;

protected:
  MZNFZNSolverFlag(const FlagType& t0, const std::string& n0) : t(t0), n(n0) {}

public:
  /// Create flag that has an argument
  static MZNFZNSolverFlag arg(const std::string& n) { return MZNFZNSolverFlag(FT_ARG, n); }
  /// Create flag that has no argument
  static MZNFZNSolverFlag noarg(const std::string& n) { return MZNFZNSolverFlag(FT_NOARG, n); }
  /// Create solver flag from standard flag
  static MZNFZNSolverFlag std(const std::string& n);
  /// Create solver flag from extra flag with name \a n and type \a t
  static MZNFZNSolverFlag extra(const std::string& n, const std::string& t);
};

/// SolverFactory's descendants create, store and destroy SolverInstances
/// A SolverFactory stores all Instances itself and upon module exit,
/// destroys them and de-registers itself from the global SolverRegistry
/// An instance of SolverFactory's descendant can be created directly
/// or by one of the specialized createF_...() functions
class SolverFactory {
protected:
  /// doCreateSI should be implemented to actually allocate a SolverInstance using new()
  virtual SolverInstanceBase* doCreateSI(std::ostream&, SolverInstanceBase::Options* opt) = 0;
  typedef std::vector<std::unique_ptr<SolverInstanceBase>> SIStorage;
  SIStorage sistorage;

protected:
  SolverFactory() { getGlobalSolverRegistry()->addSolverFactory(this); }

public:
  virtual ~SolverFactory() { getGlobalSolverRegistry()->removeSolverFactory(this); }

public:
  /// Create solver-specific options object
  virtual SolverInstanceBase::Options* createOptions(void) = 0;
  /// Function createSI also adds each SI to the local storage
  SolverInstanceBase* createSI(std::ostream& log, SolverInstanceBase::Options* opt);
  /// also providing a manual destroy function.
  /// there is no need to call it upon overall finish - that is taken care of
  void destroySI(SolverInstanceBase* pSI);

public:
  /// Process an item in the command line.
  /// Leaving this now like this because this seems simpler.
  /// We can also pass options internally between modules in this way
  /// and it only needs 1 format
  virtual bool processOption(SolverInstanceBase::Options* opt, int& i,
                             std::vector<std::string>& argv) {
    return false;
  }

  virtual std::string getDescription(SolverInstanceBase::Options* opt = NULL) = 0;
  virtual std::string getVersion(SolverInstanceBase::Options* opt = NULL) = 0;
  virtual std::string getId(void) = 0;
  virtual void printHelp(std::ostream&) {}
};  // SolverFactory

// Class MznSolver coordinates flattening and solving.
class MznSolver {
private:
  SolverInitialiser _solver_init;
  enum OptionStatus { OPTION_OK, OPTION_ERROR, OPTION_FINISH };
  /// Solver configurations
  SolverConfigs solver_configs;
  Constraint* output = nullptr;
  std::vector<BytecodeProc> bs;
  std::vector<std::string> data_files;
  Env in_out_defs;
  SolverInstanceBase* si = 0;
  SolverInstanceBase::Options* si_opt = 0;
  SolverFactory* sf = 0;
  bool is_mzn2fzn = 0;

  std::string executable_name;
  std::string file;
  std::string solver_str;
  std::ostream& os;
  std::ostream& log;
  SolverInstance::Status interpreter_status = SolverInstance::UNKNOWN;
  // Incremental interface
  std::vector<std::pair<Variable*, size_t>> def_stack = {{nullptr, 0}};
  double flatten_time = 0;

public:
  bool output_dict = false;
  Interpreter* interpreter = nullptr;
  Solns2Out s2out;
  // name -> <code, nargs>
  std::unordered_map<std::string, std::pair<int, int>> resolve_call;

  /// global options
  bool flag_verbose = false;
  bool flag_statistics = false;
  bool flag_compiler_verbose = false;
  bool flag_compiler_statistics = false;
  bool flag_is_solns2out = false;
  int flag_overall_time_limit = 0;

public:
  MznSolver(std::vector<std::string> args = {});
  ~MznSolver();

  std::pair<SolverInstance::Status, std::string> run();
  OptionStatus processOptions(std::vector<std::string>& argv);
  SolverFactory* getSF() {
    assert(sf);
    return sf;
  }
  SolverInstanceBase::Options* getSI_OPT() {
    assert(si_opt);
    return si_opt;
  }
  bool get_flag_verbose() { return flag_verbose; /*getFlt()->get_flag_verbose();*/ }
  void printUsage();
  std::string printSolution(SolverInstance::Status);

  void pushToSolver();
  void popFromSolver();
  std::pair<SolverInstance::Status, std::string> solve();

private:
  void addDefinitions();
  Val eval_val(EnvI& env, Expression* e);
  void printHelp(const std::string& selectedSolver = std::string());
  /// Flatten model
  void flatten(const std::string& filename = std::string(),
               const std::string& modelName = std::string("stdin"));
  size_t getNSolvers() { return getGlobalSolverRegistry()->getSolverFactories().size(); }
  /// If building a flattening exe only.
  bool ifMzn2Fzn();
  bool ifSolns2out();
  void addSolverInterface();
  void addSolverInterface(SolverFactory* sf);
  void printStatistics();

  SolverInstance::Status getFltStatus() { return interpreter_status; }
  SolverInstanceBase* getSI() {
    assert(si);
    return si;
  }
  bool get_flag_statistics() { return flag_statistics; }
};

}  // namespace MiniZinc

#endif