/* -*- 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_ASTSTRING_HH__
#define __MINIZINC_ASTSTRING_HH__

#include <minizinc/gc.hh>

#include <cstring>
#include <functional>
#include <iostream>
#include <string>

namespace MiniZinc {

class ASTStringO;

/**
 * \brief Handler for ASTStringO objects
 */
class ASTString {
protected:
  /// String
  ASTStringO* _s;

public:
  /// Default constructor
  ASTString(void) : _s(NULL) {}
  /// Constructor
  ASTString(ASTStringO* s) : _s(s) {}
  /// Constructor
  ASTString(const std::string& s);
  /// Copy constructor
  ASTString(const ASTString& s);
  /// Assignment operator
  ASTString& operator=(const ASTString& s);

  /// Size of the string
  unsigned int size(void) const;
  /// Underlying C string object
  const char* c_str(void) const;
  /// Conversion to STL string
  std::string str(void) const;
  /// Underlying string implementation
  ASTStringO* aststr(void) const { return _s; }

  /// Return if string is equal to \a s
  bool operator==(const ASTString& s) const;
  /// Return if string is not equal to \a s
  bool operator!=(const ASTString& s) const;

  /// Return if string is equal to \a s
  bool operator==(const std::string& s) const;
  /// Return if string is not equal to \a s
  bool operator!=(const std::string& s) const;

  /// Return if string ends with \a s
  bool endsWith(const std::string& s) const;

  /// Return if string begins with \a s
  bool beginsWith(const std::string& s) const;

  /// Compute hash value of string
  size_t hash(void) const;

  /// Mark string during garbage collection
  void mark(void) const;
};

/// Hash map from strings to \a T
template <typename T>
struct ASTStringMap {
  /// The map type specialised for ASTString
  typedef std::unordered_map<ASTString, T> t;
};

/**
 * \brief Print integer set \a s
 * \relates Gecode::IntSet
 */
template <class Char, class Traits>
std::basic_ostream<Char, Traits>& operator<<(std::basic_ostream<Char, Traits>& os,
                                             const ASTString& s) {
  return s.size() == 0 ? os : (os << s.c_str());
}

}  // namespace MiniZinc

namespace std {
template <>
struct hash<MiniZinc::ASTString> {
public:
  size_t operator()(const MiniZinc::ASTString& s) const;
};
}  // namespace std

namespace std {
template <>
struct equal_to<MiniZinc::ASTString> {
public:
  bool operator()(const MiniZinc::ASTString& s0, const MiniZinc::ASTString& s1) const;
};
}  // namespace std

namespace MiniZinc {

/**
 * \brief Garbage collected string
 */
class ASTStringO : public ASTChunk {
protected:
  /// Constructor
  ASTStringO(const std::string& s);

public:
  /// Allocate and initialise as \a s
  static ASTStringO* a(const std::string& s);
  /// Return underlying C-style string
  const char* c_str(void) const { return _data + sizeof(size_t); }
  /// Conversion to STL string
  std::string str(void) const { return std::string(c_str()); }
  /// Return size of string
  unsigned int size(void) const {
    return static_cast<unsigned int>(_size) - static_cast<unsigned int>(sizeof(size_t)) - 1;
  }
  /// Access character at position \a i
  char operator[](unsigned int i) {
    assert(i < size());
    return _data[sizeof(size_t) + i];
  }
  /// Return hash value of string
  size_t hash(void) const { return reinterpret_cast<const size_t*>(_data)[0]; }
  /// Mark for garbage collection
  void mark(void) const { _gc_mark = 1; }
};

inline ASTString::ASTString(const std::string& s) : _s(ASTStringO::a(s)) {}
inline ASTString::ASTString(const ASTString& s) : _s(s._s) {}
inline ASTString& ASTString::operator=(const ASTString& s) {
  _s = s._s;
  return *this;
}
inline unsigned int ASTString::size(void) const { return _s ? _s->size() : 0; }
inline const char* ASTString::c_str(void) const { return _s ? _s->c_str() : NULL; }
inline std::string ASTString::str(void) const { return _s ? _s->str() : std::string(""); }
inline void ASTString::mark(void) const {
  if (_s) _s->mark();
}

inline bool ASTString::operator==(const ASTString& s) const {
  return size() == s.size() && (size() == 0 || strncmp(_s->c_str(), s._s->c_str(), size()) == 0);
}
inline bool ASTString::operator!=(const ASTString& s) const { return !(*this == s); }
inline bool ASTString::operator==(const std::string& s) const {
  return size() == s.size() && (size() == 0 || strncmp(_s->c_str(), s.c_str(), size()) == 0);
}
inline bool ASTString::operator!=(const std::string& s) const { return !(*this == s); }
inline bool ASTString::endsWith(const std::string& s) const {
  return size() >= s.size() &&
         (size() == 0 || strncmp(_s->c_str() + size() - s.size(), s.c_str(), s.size()) == 0);
}
inline bool ASTString::beginsWith(const std::string& s) const {
  return size() >= s.size() && (size() == 0 || strncmp(_s->c_str(), s.c_str(), s.size()) == 0);
}

inline size_t ASTString::hash(void) const { return _s ? _s->hash() : 0; }

}  // namespace MiniZinc

namespace std {
inline size_t hash<MiniZinc::ASTString>::operator()(const MiniZinc::ASTString& s) const {
  return s.hash();
}
}  // namespace std

namespace std {
inline bool equal_to<MiniZinc::ASTString>::operator()(const MiniZinc::ASTString& s0,
                                                      const MiniZinc::ASTString& s1) const {
  return s0 == s1;
}
}  // namespace std

#endif