#include "arch/kernel/main.hpp"

#include "arch/boot/multiboot.hpp"
#include "arch/boot/pointers.hpp"
#include "arch/video/vga/text.hpp"

namespace teachos::arch::kernel
{

  auto print_meminfo(multiboot_tag * tag) -> void
  {
    using namespace video::vga;

    uint32_t * pointer = &tag->size;
    uint32_t mem_lower = *(++pointer);
    uint32_t mem_upper = *(++pointer);

    text::write("Lower memory bound: ", text::common_attributes::green_on_black);
    text::write_number(mem_lower, text::common_attributes::green_on_black);
    text::write("Upper memory bound: ", text::common_attributes::green_on_black);
    text::write_number(mem_upper, text::common_attributes::green_on_black);
  }

  auto print_memory_map(multiboot_tag * tag) -> void
  {
    using namespace video::vga;

    uint32_t * pointer = &tag->size;
    uint32_t entry_size = *(++pointer);
    uint32_t entry_version = *(++pointer);
    text::write("Version: ", text::common_attributes::green_on_black);
    text::write_number(entry_version, text::common_attributes::green_on_black);

    auto begin = (struct memory_map_entry *)++pointer;
    auto end = begin + entry_size;
    for (auto itr = begin; itr < end; ++itr)
    {
      text::write("Base Address: ", text::common_attributes::green_on_black);
      text::write_number(itr->base_addr, text::common_attributes::green_on_black);
      text::write("Length: ", text::common_attributes::green_on_black);
      text::write_number(itr->length, text::common_attributes::green_on_black);
      text::write("Type: ", text::common_attributes::green_on_black);
      text::write_number(itr->type, text::common_attributes::green_on_black);
      text::write("Reserved: ", text::common_attributes::green_on_black);
      text::write_number(itr->reserved, text::common_attributes::green_on_black);
    }
  }

  auto main() -> void
  {
    using namespace video::vga;

    text::clear();
    text::cursor(false);
    text::write("TeachOS is starting up...", text::common_attributes::green_on_black);

    auto mip = arch::boot::multiboot_information_pointer;

    // Address of the first multiboot tag
    auto multiboot_tag = (struct multiboot_tag *)((uint8_t *)mip + 8);

    /*
     * Loop over the multiboot2 tags to access the information needed.
     * Tags are defined in the header.
     */
    for (auto tag = multiboot_tag; tag->type != MULTIBOOT_TAG_TYPE_END;
         tag = (struct multiboot_tag *)((uint8_t *)tag + ((tag->size + 7) & ~7)))
    {
      switch (tag->type)
      {
        case MULTIBOOT_TAG_TYPE_BASIC_MEMINFO:
          print_meminfo(tag);
          break;
        case MULTIBOOT_TAG_TYPE_MMAP:
          print_memory_map(tag);
          break;
      }
    }
  }
}  // namespace teachos::arch::kernel