/*=============================================================================

  Library: CppMicroServices

  Copyright (c) The CppMicroServices developers. See the COPYRIGHT
  file at the top-level directory of this distribution and at
  https://github.com/CppMicroServices/CppMicroServices/COPYRIGHT .

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

=============================================================================*/

#ifndef CPPMICROSERVICES_ANYMAP_H
#define CPPMICROSERVICES_ANYMAP_H

#include "cppmicroservices/Any.h"

#include <string>
#include <unordered_map>

namespace cppmicroservices {

namespace detail {

struct any_map_cihash
{
  std::size_t operator()(const std::string& key) const;
};

struct any_map_ciequal
{
  bool operator()(const std::string& l, const std::string& r) const;
};
}

/**
 * \ingroup MicroServicesUtils
 *
 * A map data structure which wraps different STL map types.
 *
 * This is a convenience class providing a STL associative container
 * interface for different underlying container types. Supported underlying
 * types are
 * - \c any_map::ordered_any_map (a STL map)
 * - \c any_map::unordered_any_map (a STL unordered map)
 * - \c any_map::unordered_any_cimap (a STL unordered map with case insensitive key comparison)
 *
 * This class provides most of the STL functions for associated containers,
 * including forward iterators. It is typically not instantiated by clients
 * directly, but obtained via framework API calls, returning an \c AnyMap
 * sub-class instance.
 *
 * @see AnyMap
 */
class US_Framework_EXPORT any_map
{

public:
  typedef std::string key_type;
  typedef Any mapped_type;
  typedef std::pair<const key_type, mapped_type> value_type;
  typedef std::size_t size_type;
  typedef std::ptrdiff_t difference_type;
  typedef value_type& reference;
  typedef value_type const& const_reference;
  typedef value_type* pointer;
  typedef value_type const* const_pointer;

  typedef std::map<std::string, Any> ordered_any_map;
  typedef std::unordered_map<std::string, Any> unordered_any_map;
  typedef std::unordered_map<std::string,
                             Any,
                             detail::any_map_cihash,
                             detail::any_map_ciequal>
    unordered_any_cimap;

  enum map_type : uint8_t
  {
    ORDERED_MAP,
    UNORDERED_MAP,
    UNORDERED_MAP_CASEINSENSITIVE_KEYS
  };

private:
  class US_Framework_EXPORT iterator_base
  {
    friend class any_map;

  protected:
    enum iter_type : uint8_t
    {
      NONE,
      ORDERED,
      UNORDERED,
      UNORDERED_CI
    };

    iter_type type;

    iterator_base()
      : type(NONE)
    {}

    iterator_base(iter_type type)
      : type(type)
    {}

  public:
    typedef any_map::value_type value_type;

    typedef std::forward_iterator_tag iterator_category;
    typedef any_map::difference_type difference_type;
  };

public:
  class iter;

  class US_Framework_EXPORT const_iter : public iterator_base
  {
  private:
    typedef ordered_any_map::const_iterator ociter;
    typedef unordered_any_map::const_iterator uociter;
    typedef unordered_any_cimap::const_iterator uocciiter;

  public:
    typedef any_map::const_reference reference;
    typedef any_map::const_pointer pointer;

    typedef const_iter iterator;

    const_iter();
    const_iter(const iterator& it);
    const_iter(const iter& it);
    ~const_iter();

    const_iter(ociter&& it);
    const_iter(uociter&& it, iter_type type);

    reference operator*() const;
    pointer operator->() const;

    iterator& operator++();
    iterator operator++(int);

    bool operator==(const iterator& x) const;
    bool operator!=(const iterator& x) const;

  private:
    ociter const& o_it() const;
    ociter& o_it();
    uociter const& uo_it() const;
    uociter& uo_it();
    uocciiter const& uoci_it() const;
    uocciiter& uoci_it();

    union
    {
      ociter* o;
      uociter* uo;
      uocciiter* uoci;
    } it;
  };

  class US_Framework_EXPORT iter : public iterator_base
  {
  private:
    typedef ordered_any_map::iterator oiter;
    typedef unordered_any_map::iterator uoiter;
    typedef unordered_any_cimap::iterator uociiter;

  public:
    typedef any_map::reference reference;
    typedef any_map::pointer pointer;

    typedef iter iterator;

    iter();
    iter(const iter& it);
    ~iter();

    iter(oiter&& it);
    iter(uoiter&& it, iter_type type);

    reference operator*() const;
    pointer operator->() const;

    iterator& operator++();
    iterator operator++(int);

    bool operator==(const iterator& x) const;
    bool operator!=(const iterator& x) const;

  private:
    friend class const_iter;

    oiter const& o_it() const;
    oiter& o_it();
    uoiter const& uo_it() const;
    uoiter& uo_it();
    uociiter const& uoci_it() const;
    uociiter& uoci_it();

    union
    {
      oiter* o;
      uoiter* uo;
      uociiter* uoci;
    } it;
  };

  typedef iter iterator;
  typedef const_iter const_iterator;

  any_map(map_type type);
  any_map(const ordered_any_map& m);
  any_map(const unordered_any_map& m);
  any_map(const unordered_any_cimap& m);

  any_map(const any_map& m);
  any_map& operator=(const any_map& m);

  ~any_map();

  iter begin();
  const_iter begin() const;
  const_iter cbegin() const;
  iter end();
  const_iter end() const;
  const_iter cend() const;

  bool empty() const;
  size_type size() const;
  size_type count(const key_type& key) const;
  void clear();

  mapped_type& at(const key_type& key);
  const mapped_type& at(const key_type& key) const;

  mapped_type& operator[](const key_type& key);
  mapped_type& operator[](key_type&& key);

  std::pair<iterator, bool> insert(const value_type& value);
  const_iterator find(const key_type& key) const;

protected:
  map_type type;

private:
  ordered_any_map const& o_m() const;
  ordered_any_map& o_m();
  unordered_any_map const& uo_m() const;
  unordered_any_map& uo_m();
  unordered_any_cimap const& uoci_m() const;
  unordered_any_cimap& uoci_m();

  union
  {
    ordered_any_map* o;
    unordered_any_map* uo;
    unordered_any_cimap* uoci;
  } map;
};

/**
 * \ingroup MicroServicesUtils
 *
 * A map data structure with support for compound keys.
 *
 * This class adds convenience functions on top of the \c any_map
 * class. The \c any_map is a recursive data structure, and its values can be
 * retrieved via standard map functions or by using a dotted key notation
 * specifying a compound key.
 *
 * @see any_map
 */
class US_Framework_EXPORT AnyMap : public any_map
{
public:
  AnyMap(map_type type);
  AnyMap(const ordered_any_map& m);
  AnyMap(const unordered_any_map& m);
  AnyMap(const unordered_any_cimap& m);

  /**
   * Get the underlying STL container type.
   *
   * @return The STL container type holding the map data.
   */
  map_type GetType() const;

  /**
   * Get a key's value, using a compound key notation.
   *
   * A compound key consists of one or more key names, concatenated with
   * the '.' (dot) character. Each key except the last requires the referenced
   * Any object to be of type \c AnyMap or \c std::vector<Any>. Containers
   * of type \c std::vector<Any> are indexed using 0-based numerical key names.
   *
   * For example, a \c AnyMap object holding data of the following layout
   * \code{.json}
   * {
   *   one: 1,
   *   two: "two",
   *   three: {
   *     a: "anton",
   *     b: [ 3, 8 ]
   *   }
   * }
   * \endcode
   * can be queried using the following notation:
   * \code
   * map.AtCompoundKey("one");       // returns Any(1)
   * map.AtCompoundKey("three.a");   // returns Any(std::string("anton"))
   * map.AtCompoundKey("three.b.1"); // returns Any(8)
   * \endcode
   *
   * @param key The key hierachy to query.
   * @return A reference to the key's value.
   *
   * @throws std::invalid_argument if the \c Any value for a given key is not of type \c AnyMap or \c std::vector<Any>.
   * @throws std::out_of_range if the key is not found or a numerical index would fall out of the range of an \c int type.
   */
  mapped_type& AtCompoundKey(const key_type& key);
  const mapped_type& AtCompoundKey(const key_type& key) const;
};

template<>
US_Framework_EXPORT std::ostream& any_value_to_string(std::ostream& os,
                                                      const AnyMap& m);

template<>
US_Framework_EXPORT std::ostream& any_value_to_json(std::ostream& os,
                                                    const AnyMap& m);
}

#endif // CPPMICROSERVICES_ANYMAP_H