#pragma once

#include <charconv>
#include <ranges>
#include <regex>

namespace mcc::utils
{

static const std::regex decimalNumberRx{" *[-+]?([0-9]*[.])?[0-9]+([eE][-+]?[0-9]+)? *"};
static const std::regex sexagesimalReprRx{" *[-+]?[0-9]{1,2}:[0-9]{1,2}:([0-9]{0,2}[.])?[0-9]+ *"};

enum class TrimType { TRIM_LEFT, TRIM_RIGHT, TRIM_BOTH };

template <std::ranges::contiguous_range R>
static std::string_view trimSpaces(R&& r, TrimType type = TrimType::TRIM_BOTH)
    requires std::same_as<char, std::remove_cvref_t<std::ranges::range_value_t<R>>>
{
    auto is_space = [](const auto& ch) { return ch == ' '; };

    auto end = std::forward<R>(r).end();

    auto f1 = std::forward<R>(r).begin();

    if (type != TrimType::TRIM_RIGHT) {
        // look for the first non-space symbol
        f1 = std::ranges::find_if_not(std::forward<R>(r), is_space);
        if (f1 == end) {  // all are spaces!
            return std::string_view();
        }
    }

    auto f2 = end;

    if (type != TrimType::TRIM_LEFT) {
        auto f3 = f1;

        do {
            f2 = std::ranges::find_if(++f3, end, is_space);
            if (f2 == end)
                break;
            f3 = std::ranges::find_if_not(f2 + 1, end, is_space);
        } while (f3 != end);
    }

    return std::string_view(f1, f2);
}


template <typename T, std::ranges::contiguous_range R>
std::optional<T> numFromStr(R&& r)
    requires((std::integral<T> || std::floating_point<T>) &&
             std::same_as<char, std::remove_cvref_t<std::ranges::range_value_t<R>>>)
{
    T val;
    const char* end_ptr = &*r.end();

    if constexpr (std::integral<T>) {
        auto cvt_res = std::from_chars(&*r.begin(), &*r.end(), val);
        if (cvt_res.ec != std::errc()) {
            return std::nullopt;
        } else if (cvt_res.ptr != end_ptr) {
            return std::nullopt;
        }
    } else {
#ifdef _LIBCPP_VERSION  // clang's libc++ does not have floating-point overloads for std::from_chars
        std::string s{str.begin(), str.end()};
        size_t pos;

        try {
            if constexpr (std::same_as<T, float>) {
                val = std::stof(s, &pos);
            } else if constexpr (std::same_as<T, double>) {
                val = std::stod(s, &pos);
            } else {
                val = std::stold(s, &pos);
            }
        } catch (...) {
            return std::nullopt;
        }

        if (pos != s.size()) {
            return std::nullopt;
        }
#else
        auto cvt_res = std::from_chars(&*r.begin(), &*r.end(), val);

        if (cvt_res.ec != std::errc()) {
            return std::nullopt;
        } else if (cvt_res.ptr != end_ptr) {
            return std::nullopt;
        }
#endif
    }

    return val;
}

template <std::ranges::contiguous_range R>
static std::optional<double> parsAngleString(R&& r, bool hms = false)
    requires std::same_as<char, std::remove_cvref_t<std::ranges::range_value_t<R>>>
{
    auto str = trimSpaces(std::forward<R>(r));

    bool ok = std::regex_match(str.begin(), str.end(), decimalNumberRx);

    if (ok) {
        return numFromStr<double>(str);
    }

    ok = std::regex_match(str.begin(), str.end(), sexagesimalReprRx);

    if (ok) {
        auto str = trimSpaces(std::forward<R>(r));
        auto parts = std::views::split(str, std::string_view(":"));

        double val;

        double p1 = numFromStr<double>(*parts.begin()).value();
        val = std::abs(p1);
        double dv = 60.0;
        for (auto const& v : parts | std::views::drop(1)) {
            val += numFromStr<double>(v).value() / dv;
            dv *= 60.0;
        }
        // val += numFromStr<double>(parts[1]) / 60.0;
        // val += numFromStr<double>(parts[2]) / 3600.0;
        if (p1 < 0) {
            val = -val;
        }

        if (hms) {
            val *= 15.0;
        }

        return val;
    }


    return std::nullopt;
}

}  // namespace mcc::utils