roro9stack/lib/ui/src/line_editor.h

#pragma once

#include <cstdint>
#include <string>

namespace roro {

// Single-line UTF-8 text editing. The cursor is a byte index always on a character boundary,
// and the text never exceeds maxBytes (protocol fields are limited in bytes, not characters).
class LineEditor {
   public:
    explicit LineEditor(size_t maxBytes) : max_(maxBytes) {}

    void setText(const std::string& text);  // truncates, cursor to end
    const std::string& text() const { return text_; }
    size_t cursor() const { return cursor_; }
    size_t maxBytes() const { return max_; }

    bool insert(uint32_t codePoint);  // false if it would not fit
    void backspace();
    void left();
    void right();
    void home() { cursor_ = 0; }
    void end() { cursor_ = text_.size(); }

   private:
    size_t max_;
    std::string text_;
    size_t cursor_ = 0;
};

}  // namespace roro