language.hpp

// Copyright Take Vos 2020-2022.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "../utility/module.hpp"
#include "../i18n/language_tag.hpp"
#include <string>
#include <vector>
#include <functional>
#include <mutex>
#include <format>
 
namespace hi::inline v1 {
 
class language {
public:
    language_tag tag;
    std::function<int(int)> plurality_func;
 
    language(language_tag tag) noexcept;
    language(language const &) = delete;
    language(language &&) = delete;
    language &operator=(language const &) = delete;
    language &operator=(language &&) = delete;
 
    [[nodiscard]] ssize_t plurality(long long n, ssize_t max) const noexcept
    {
        auto r = 0;
        if (plurality_func) {
            r = plurality_func(narrow_cast<int>(n % 1'000'000));
        } else {
            // Use English as fallback.
            r = static_cast<int>(n == 1);
        }
        return std::clamp(narrow_cast<ssize_t>(r), ssize_t{0}, max - 1);
    }
 
    [[nodiscard]] static language *find(language_tag const &tag) noexcept
    {
        hilet lock = std::scoped_lock(_mutex);
 
        hilet i = _languages.find(tag);
        if (i != _languages.end()) {
            return i->second.get();
        } else {
            return nullptr;
        }
    }
 
    [[nodiscard]] static language &find_or_create(language_tag const &tag) noexcept
    {
        hilet lock = std::scoped_lock(_mutex);
 
        auto *r = find(tag);
        if (!r) {
            auto tmp = std::make_unique<language>(tag);
            r = tmp.get();
            _languages[tag] = std::move(tmp);
        }
        return *r;
    }
 
    [[nodiscard]] static std::vector<language *> make_languages(std::vector<language_tag> tags) noexcept
    {
        hilet lock = std::scoped_lock(_mutex);
 
        auto variant_tags = variants(tags);
        auto r = std::vector<language *>{};
        r.reserve(variant_tags.size());
 
        for (hilet &tag: variant_tags) {
            r.push_back(&find_or_create(tag));
        }
 
        return r;
    }
 
private:
    inline static std::atomic<bool> _is_running;
    inline static std::unordered_map<language_tag, std::unique_ptr<language>> _languages;
    inline static std::recursive_mutex _mutex;
};
 
} // namespace hi::inline v1
 
template<typename CharT>
struct std::formatter<std::vector<hi::language *>, CharT> : std::formatter<std::string_view, CharT> {
    auto format(std::vector<hi::language *> const &t, auto &fc)
    {
        auto r = std::string{};
        for (hilet language : t) {
            if (not r.empty()) {
                r += ", ";
            }
            r += language->tag.to_string();
        }
        return std::formatter<std::string_view, CharT>::format(r, fc);
    }
};