#pragma once



#include <algorithm>
#include <string>
#include <vector>


#include "../common/adc_traits.h"
#include "../common/adc_utils.h"

namespace adc
{

namespace utils {


template<typename ByteStorageT, typename T, typename... Ts>
void convertToBytes(ByteStorageT &res, const T &v, const Ts &...vs)
{
    if constexpr (std::is_array_v<std::remove_cvref_t<T>>) { // to handle with trailing '\0' in plain char array
        convertToBytes(res, std::string_view(v), vs...);
    } else {
        if constexpr (traits::adc_input_char_range<T>) {
            std::ranges::copy(v, std::back_inserter(res));
        } else if constexpr (std::convertible_to<T, ByteStorageT>) {
            convertToBytes(res, static_cast<ByteStorageT>(v), vs...);
        } else if constexpr (traits::formattable<T>) {
            std::format_to(std::back_inserter(res), "{}", v);
        } else {
            static_assert(false, "UNSUPPORTED TYPE!!!");
        }
    }

    if constexpr (sizeof...(Ts)) {
        convertToBytes(res, vs...);
    }
}


} // namespace utils


namespace traits {

template<typename T>
concept adc_netmessage_c = requires(const T t) { // const methods
    { t.empty() } -> std::convertible_to<bool>;
    { t.bytes() } -> adc_output_char_range;
    { t.byteView() } -> adc_range_of_view_char_range;
};

} // namespace traits


/*
    Trivial message interface:
        byte storage: just a char-range
*/
template<traits::adc_output_char_range ByteStorageT = std::string, traits::adc_char_view ByteViewT = std::string_view>
class AdcNetMessageTrivialInterface
{
public:

    virtual ~AdcNetMessageTrivialInterface() = default;

    bool empty() const { return std::ranges::distance(_bytes.begin(), _bytes.end()) == 0; }

    // get a copy of message bytes
    template<traits::adc_output_char_range R>
    R bytes() const
    {
        R r;
        std::ranges::copy(_bytes, std::back_inserter(r));

        return r;
    }


    virtual ByteStorageT bytes() const
    {
        //
        return bytes<ByteStorageT>();
    }

    // get a view of message bytes
    template<traits::adc_range_of_view_char_range R>
    R bytesView() const
    {
        R r;

        r.emplace_back(_bytes.begin(), _bytes.end());

        return r;
    }

    std::vector<ByteViewT> bytesView() const
    {
        //
        return bytesView<std::vector<ByteViewT>>();
    }

protected:
    ByteStorageT _bytes;

    AdcNetMessageTrivialInterface() = default;
};



/*
    interface for more complex messages:
        byte storage: std::vector of char-range (sequence of buffers)
*/
template<traits::adc_output_char_range ByteStorageT = std::string, traits::adc_char_view ByteViewT = std::string_view>
class AdcNetMessageSeqInterface
{
public:
    virtual ~AdcNetMessageSeqInterface() = default;

    bool empty() const
    {
        if (_bytes.empty()) {
            return true;
        }

        bool emp = true;
        for (const auto &el : _bytes) {
            if (std::ranges::distance(el.begin(), el.end())) {
                emp = false;
                break;
            }
        }

        return emp;
    }

    // get a copy of message bytes
    template<traits::adc_output_char_range R>
    R bytes() const
    {
        R r;

        for (size_t i = 0; i < _bytes.size(); ++i) {
            std::ranges::for_each(storageViewByIndex(i),
                                  [&r](const auto &el) { std::ranges::copy(el, std::back_inserter(r)); });
        }

        return r;
    }


    virtual ByteStorageT bytes() const
    {
        //
        return bytes<ByteStorageT>();
    }

    // get a view of message bytes
    template<traits::adc_range_of_view_char_range R>
    R bytesView() const
    {
        R r;


        for (size_t i = 0; i < _bytes.size(); ++i) {
            std::ranges::for_each(storageViewByIndex(i), [&r](const auto &el) { r.emplace_back(el.begin(), el.end()); });
        }

        return r;
    }

    std::vector<ByteViewT> bytesView() const
    {
        //
        return bytesView<std::vector<ByteViewT>>();
    }

protected:
    std::vector<ByteStorageT> _bytes;


    AdcNetMessageSeqInterface() = default;

    // return a sequence of storage element view and possible additional
    // byte views (e.g. elements delimiter)
    virtual std::vector<ByteViewT> storageViewByIndex(size_t) const = 0;
};






// Generic message class
template <traits::adc_output_char_range ByteStorageT = std::string, traits::adc_char_view ByteViewT = std::string_view>
class AdcGenericNetMessage : public AdcNetMessageTrivialInterface<ByteStorageT, ByteViewT>
{
    using base_t = AdcNetMessageTrivialInterface<ByteStorageT, ByteViewT>;

public:
    using base_t::base_t;
    using base_t::bytes;
    using base_t::bytesView;
    using base_t::empty;


    template<typename T, typename... Ts>
    AdcGenericNetMessage(const T &v, const Ts &...vs) : AdcGenericNetMessage()
    {
        appendBytes(v, vs...);
    }


    template <typename T, typename... Ts>
    void appendBytes(const T& v, const Ts&... vs)
    {
        utils::convertToBytes(this->_bytes, v, vs...);
    }

    template <typename T, typename... Ts>
    void setBytes(const T& v, const Ts&... vs)
    {
        this->_bytes = ByteStorageT();

        appendBytes(v, vs...);
    }


    template <std::input_iterator IT>
    void appendFromBytes(IT begin, IT end)
        requires std::same_as<std::iter_value_t<IT>, char>
    {
        std::copy(begin, end, std::back_inserter(this->_bytes));
    }


    template <std::input_iterator IT>
    void setFromBytes(IT begin, IT end)
        requires std::same_as<std::iter_value_t<IT>, char>
    {
        this->_bytes = ByteStorageT();

        appendFromBytes(begin, end);
    }
};


namespace constants
{
static constexpr char ADC_DEFAULT_TOKEN_DELIMITER[] = " ";
static constexpr char ADC_DEFAULT_KEY_TOKEN_DELIMITER[] = " ";

}  // namespace constants


template <const char* TOKEN_DELIM = constants::ADC_DEFAULT_TOKEN_DELIMITER,
          traits::adc_output_char_range ByteStorageT = std::string,
          traits::adc_char_view ByteViewT = std::string_view>
class AdcTokenNetMessage : public AdcNetMessageSeqInterface<ByteStorageT, ByteViewT>
{
    // AdcNetMessageSeqInterface<ByteStorageT, ByteViewT>::_bytes - tokens
    using base_t = AdcNetMessageSeqInterface<ByteStorageT, ByteViewT>;

public:
    static constexpr std::string_view tokenDelimiter{TOKEN_DELIM};

    using base_t::bytesView;
    using base_t::bytes;
    using base_t::empty;

    AdcTokenNetMessage() = default;

    template <typename T, typename... Ts>
    AdcTokenNetMessage(const T& v, const Ts&... vs) : AdcTokenNetMessage()
    {
        setTokens(v, vs...);
    }

    virtual ~AdcTokenNetMessage() = default;


    template <std::ranges::output_range<ByteStorageT> R>
    R tokens(size_t start = 0, size_t N = std::numeric_limits<size_t>::max()) const
    {
        R r;

        if (empty()) {
            return r;
        }

        std::ranges::copy(this->_bytes | std::views::drop(start) | std::views::take(N), std::back_inserter(r));

        return r;
    }

    std::vector<ByteStorageT> tokens(size_t start = 0, size_t N = std::numeric_limits<size_t>::max()) const
    {
        //
        return tokens<std::vector<ByteStorageT>>(start, N);
    }


    template <typename T, typename... Ts>
    void appendTokens(const T& v, const Ts&... vs)
    {
        if constexpr (traits::adc_input_char_range<T> || traits::formattable<T>) {
            utils::convertToBytes(this->_bytes.emplace_back(), v);
        } else if constexpr (std::ranges::input_range<T>) {
            using el_t = std::ranges::range_value_t<T>;
            static_assert(traits::adc_input_char_range<el_t> || traits::formattable<el_t>,
                          "INVALID TYPE OF INPUT TOKENS!!!");

            if (std::ranges::distance(v.begin(), v.end())) {
                for (const auto& el : v) {
                    utils::convertToBytes(this->_bytes.emplace_back(), el);
                }
            }

        } else {
            static_assert(false, "UNSUPPORTED (CANNOT BE SERIALIZED TO BYTES) TYPE OF INPUT TOKENS!!!");
        }

        if constexpr (sizeof...(Ts)) {
            appendTokens(vs...);
        }
    }


    template <typename T, typename... Ts>
    void setTokens(const T& v, const Ts&... vs)
    {
        this->_bytes.clear();

        appendTokens(v, vs...);
    }


    template <std::input_iterator IT>
    void appendFromBytes(IT begin, IT end)
        requires std::same_as<std::iter_value_t<IT>, char>
    {
        auto it = begin, start_it = begin;

        do {
            it = std::search(start_it, end, tokenDelimiter.begin(), tokenDelimiter.end());
            std::copy(start_it, it, std::back_inserter(this->_bytes.emplace_back()));
            start_it = it;
            std::advance(start_it, tokenDelimiter.size()); // to support not only random-access iterators
        } while (it != end);
    }


    template <std::input_iterator IT>
    void setFromBytes(IT begin, IT end)
        requires std::same_as<std::iter_value_t<IT>, char>
    {
        this->_bytes.clear();

        appendFromBytes(begin, end);
    }

protected:
    virtual std::vector<ByteViewT> storageViewByIndex(size_t idx) const override
    {
        const ByteStorageT &el = this->_bytes[idx];
        std::vector<ByteViewT> vw{{el.begin(), el.end()}};

        auto last_idx = this->_bytes.size() - 1;
        if (idx < last_idx) { // add delimiter
            vw.emplace_back(tokenDelimiter.begin(), tokenDelimiter.end());
        }

        return vw;
    }
};


// special type of tokenized message:
//    the first token is keyword
//    the other - just tokens
// delimiter between keyword and other tokens may differ from token-to-token one
template <const char* KEY_TOKEN_DELIM = constants::ADC_DEFAULT_KEY_TOKEN_DELIMITER,
          const char* TOKEN_DELIM = constants::ADC_DEFAULT_TOKEN_DELIMITER,
          traits::adc_output_char_range ByteStorageT = std::string,
          traits::adc_char_view ByteViewT = std::string_view>
class AdcKeyTokenNetMessage : public AdcTokenNetMessage<TOKEN_DELIM, ByteStorageT, ByteViewT>
{
    using base_t = AdcTokenNetMessage<TOKEN_DELIM, ByteStorageT, ByteViewT>;

public:
    static constexpr std::string_view keytokenDelimiter{KEY_TOKEN_DELIM};

    using base_t::appendTokens;
    using base_t::setTokens;
    using base_t::tokens;
    using base_t::appendFromBytes; // append only tokens not keyword
    using base_t::bytesView;
    using base_t::bytes;
    using base_t::empty;


    AdcKeyTokenNetMessage() = default;


    template<typename KT, typename T, typename... Ts>
    AdcKeyTokenNetMessage(const KT &key, const T &tok, const Ts &...toks)
    {
        utils::convertToBytes(this->_bytes.emplace_back(), key);
        setTokens(tok, toks...);
    }


    virtual ~AdcKeyTokenNetMessage() = default;

    template <traits::adc_output_char_range R>
    R keyBytes() const
    {
        R r;

        if (empty()) {
            return r;
        }

        std::ranges::copy(this->_bytes[0], r);

        return r;
    }


    ByteStorageT keyBytes() const
    {
        if (empty()) {
            return ByteStorageT();
        }

        return this->_bytes[0];
    }


    template <traits::adc_char_view R>
    R keyView() const
    {
        if (empty()) {
            return R();
        }

        return R{this->_bytes[0].begin(), this->_bytes[0].end()};
    }


    ByteViewT keyView() const
    {
        if (empty()) {
            return ByteViewT();
        }

        return ByteViewT{this->_bytes[0].begin(), this->_bytes[0].end()};
    }

    template<std::ranges::output_range<ByteStorageT> R>
    R tokens(size_t start = 0, size_t N = std::numeric_limits<size_t>::max()) const
    {
        // "+1" since the first element is keyword
        return base_t::template tokens<R>(start + 1, N);
    }

    std::vector<ByteStorageT> tokens(size_t start = 0, size_t N = std::numeric_limits<size_t>::max()) const
    {
        //
        return tokens<std::vector<ByteStorageT>>(start, N);
    }


    template<typename KT, typename T, typename... Ts>
    void setKeyTokens(const KT &key, const T &tok, const Ts &...toks)
    {
        this->_bytes.clear();

        utils::convertToBytes(this->_bytes.emplace_back(), key);
        appendTokens(tok, toks...);
    }


    template <typename T, typename... Ts>
    void setTokens(const T& v, const Ts&... vs)
    {
        this->_bytes.resize(1); // the first element is keyword

        appendTokens(v, vs...);
    }


    template<std::input_iterator IT>
    void setFromBytes(IT begin, IT end)
        requires std::same_as<std::iter_value_t<IT>, char>
    {
        this->_bytes.clear();

        auto it = std::search(begin, end, keytokenDelimiter.begin(), keytokenDelimiter.end());

        std::copy(begin, it, std::back_inserter(this->_bytes.emplace_back())); // keyword

        if (it != end) {
            std::advance(it, keytokenDelimiter.size());
            appendFromBytes(it, end); // tokens
        }
    }

protected:

    virtual std::vector<ByteViewT> storageViewByIndex(size_t idx) const override
    {
        if (idx == 0) { // the first element is keyword
            const ByteStorageT &el = this->_bytes[idx];
            std::vector<ByteViewT> vw{{el.begin(), el.end()}};

            if (this->_bytes.size() > 1) { // there are tokens, so add keyword-to-tokens delimiter
                vw.emplace_back(keytokenDelimiter.begin(), keytokenDelimiter.end());
            }

            return vw;
        } else {
            return base_t::storageViewByIndex(idx);
        }
    }
};

}  // namespace adc