#include "arch/video/vga/text.hpp"

#include "arch/boot/pointers.hpp"
#include "arch/video/vga/io.hpp"
#include "memory/asm_pointer.hpp"

#include <algorithm>
#include <string_view>
#include <utility>

namespace teachos::arch::video::vga::text
{

  namespace
  {
    auto constexpr default_text_buffer_address = 0xb8000;

    extern "C" std::pair<char, attribute> * vga_buffer_pointer;
    auto constinit text_buffer = teachos::memory::asm_pointer{vga_buffer_pointer};

    auto write(char code_point, attribute attribute) -> void
    {
      auto & p = *text_buffer;
      (*p++) = std::pair{code_point, attribute};
    };
  }  // namespace

  auto clear(attribute attribute) -> void
  {
    *text_buffer = reinterpret_cast<decltype(text_buffer)::pointer>(default_text_buffer_address);
    std::ranges::fill_n(*text_buffer, 2000, std::pair{' ', attribute});
  }

  auto cursor(bool enabled) -> void
  {
    auto cursor_disable_byte = std::byte{!enabled} << 5;

    crtc::address_port::write(crtc::registers::cursor_start);
    crtc::data_port::write(vga::crtc::data_port::read() | cursor_disable_byte);
  }

  auto write(std::string_view code_points, attribute attribute) -> void
  {
    std::ranges::for_each(code_points, [&](auto code_point) { write(code_point, attribute); });
  }

}  // namespace teachos::arch::video::vga::text