KeyboardModifiers.hpp

// Copyright 2020 Pokitec
// All rights reserved.
 
#pragma once
 
#include "TTauri/Foundation/required.hpp"
#include "TTauri/Foundation/exceptions.hpp"
#include "TTauri/Foundation/strings.hpp"
#include <cstdint>
 
namespace tt {
 
enum class KeyboardModifiers : uint8_t {
    None = 0x00,
    Shift = 0x01,   
    Control = 0x02, 
    Alt = 0x04,     
    Super = 0x08,   
};
 
[[nodiscard]] constexpr KeyboardModifiers operator|(KeyboardModifiers lhs, KeyboardModifiers rhs) noexcept
{
    return static_cast<KeyboardModifiers>(static_cast<uint8_t>(lhs) | static_cast<uint8_t>(rhs));
}
 
constexpr KeyboardModifiers &operator|=(KeyboardModifiers &lhs, KeyboardModifiers rhs) noexcept
{
    lhs = lhs | rhs;
    return lhs;
}
 
[[nodiscard]] constexpr bool operator>=(KeyboardModifiers lhs, KeyboardModifiers rhs) noexcept {
    ttlet lhs_ = static_cast<uint8_t>(lhs);
    ttlet rhs_ = static_cast<uint8_t>(rhs);
    return (lhs_ & rhs_) == rhs_;
}
 
inline KeyboardModifiers to_KeyboardModifiers(std::string_view s)
{
    if (ssize(s) == 0) {
        TTAURI_THROW(parse_error("Empty keyboard modifier"));       
    }
 
    // Remove the canonical trailing '+'.
    ttlet s_lower = to_lower(
        (s.back() == '+') ? s.substr(0, ssize(s) - 1) : s
    );
 
    if (s_lower == "shift") {
        return KeyboardModifiers::Shift;
    } else if (s_lower == "control" || s_lower == "ctrl" || s_lower == "cntr") {
        return KeyboardModifiers::Control;
    } else if (s_lower == "alt" || s_lower == "option" || s_lower == "meta") {
        return KeyboardModifiers::Alt;
    } else if (
        s_lower == "windows" || s_lower == "win" ||
        s_lower == "command" || s_lower == "cmd" ||
        s_lower == "super"
    ) {
        return KeyboardModifiers::Super;
    } else {
        TTAURI_THROW(parse_error("Unknown keyboard modifier '{}'", s));
    }
}
 
inline std::string to_string(KeyboardModifiers modifiers)
{
    auto r = std::string{};
 
    if (modifiers >= KeyboardModifiers::Shift) {
        r += "shift+";
    }
    if (modifiers >= KeyboardModifiers::Control) {
        r += "control+";
    }
    if (modifiers >= KeyboardModifiers::Alt) {
        r += "alt+";
    }
    if (modifiers >= KeyboardModifiers::Super) {
        r += "super+";
    }
 
    return r;
}
 
inline std::ostream &operator<<(std::ostream &lhs, KeyboardModifiers const &rhs)
{
    return lhs << to_string(rhs);
}
 
}
 
namespace std {
 
template<>
struct hash<tt::KeyboardModifiers> {
    [[nodiscard]] size_t operator() (tt::KeyboardModifiers const &rhs) const noexcept {
        return std::hash<uint8_t>{}(static_cast<uint8_t>(rhs));
    }
};
 
}