/*
 * 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.
 *
 * Copyright 2011-2016 Danny Robson <danny@nerdcruft.net>
 */

#ifndef CRUFT_UTIL_STRING_HPP
#define CRUFT_UTIL_STRING_HPP

#include "debug.hpp"
#include "view.hpp"


namespace util {
    std::string to_utf8 (const wchar_t*);
    std::string to_utf8 (const std::wstring&);
}


bool
strbegins(const char *restrict str,
          const char *restrict prefix);


namespace util {
    template <typename Iterator>
    struct tokeniser {
    public:
        using value_type = typename std::iterator_traits<Iterator>::value_type;
        using range_type = view<Iterator>;

        tokeniser (util::view<Iterator,Iterator> _range, value_type _separator):
            m_range (_range),
            m_separator (_separator)
        { ; }

        tokeniser (const char *_range, char _separator):
            m_range (_range),
            m_separator (_separator)
        { ; }

        struct iterator : public std::iterator<
            std::forward_iterator_tag,
            range_type,
            std::size_t
        > {
        public:
            iterator  operator++ (int)
            {
                iterator res(*this);
                ++*this;
                return res;
            }

            iterator& operator++ (void)&
            {
                auto newend = m_range.cend ();
                if (newend != m_end) {
                    CHECK_EQ (*m_range.cend (), m_separator);
                    newend++;
                }

                m_range = {
                    newend,
                    std::find (newend, m_end, m_separator)
                };

                return *this;
            }

            iterator operator+ (int count)
            {
                auto next = *this;
                std::advance (next, count);
                return next;
            }

            const range_type& operator* (void) const
            {
                return m_range;
            }

            const range_type* operator-> (void) const
            {
                return &m_range;
            }

            bool operator== (const iterator &rhs) const
            {
                return m_range == rhs.m_range && m_separator == rhs.m_separator;
            }

            bool operator!= (const iterator &rhs) const
            {
                return !(*this == rhs);
            }

        private:
            iterator (range_type _range, value_type _separator):
                m_separator (_separator),
                m_range (_range.cbegin (),
                    std::find (_range.cbegin (),
                    _range.cend (),
                    _separator)
                ),
                m_end (_range.cend ())
            { ;  }

            value_type m_separator;
            range_type m_range;
            Iterator m_end;

            friend tokeniser;
        };

        iterator cbegin (void) const { return { m_range, m_separator }; }
        iterator  begin (void) const { return { m_range, m_separator }; }

        iterator cend (void) const { return { { m_range.cend (), m_range.cend () }, m_separator }; }
        iterator  end (void) const { return { { m_range.cend (), m_range.cend () }, m_separator }; }

    private:
        const range_type m_range;
        const value_type m_separator;
    };


    template <typename ContainerT>
    tokeniser (ContainerT&, typename ContainerT::value_type) -> tokeniser<typename ContainerT::iterator>;

    tokeniser (const char*,char) -> tokeniser<const char*>;

    ///////////////////////////////////////////////////////////////////////////
    template <typename CharT, std::size_t LengthV>
    auto
    make_tokeniser (CharT (&data)[LengthV], CharT separator)
    {
        return tokeniser { std::begin (data), std::end (data), separator };
    }
}

#endif // __UTIL_STRING_HPP