#include "arch/memory/multiboot/reader.hpp"

#include "arch/boot/pointers.hpp"
#include "arch/exception_handling/assert.hpp"
#include "multiboot2/information.hpp"
// #include "arch/memory/multiboot/elf_symbols_section.hpp"
// #include "arch/memory/multiboot/info.hpp"

#include <algorithm>
#include <ranges>

// namespace teachos::arch::memory::multiboot
// {
//   namespace
//   {
//     template<typename T>
//       requires std::is_pointer<T>::value
//     auto align_to_8_byte_boundary(T ptr, uint32_t size) -> T
//     {
//       return reinterpret_cast<T>(reinterpret_cast<uint8_t *>(ptr) + ((size + 7) & ~7));
//     }

//     auto process_memory_map(memory_map_header * mminfo) -> memory_area_container
//     {
//       auto const expected_entry_size = mminfo->entry_size;
//       auto constexpr actual_entry_size = sizeof(memory_area);
//       exception_handling::assert(expected_entry_size == actual_entry_size,
//                                  "[Multiboot Reader] Unexpected memory area entry size");

//       auto const total_size = mminfo->info.size;
//       auto const total_entries_size = total_size - sizeof(memory_map_header) + actual_entry_size;
//       auto const number_of_entries = total_entries_size / actual_entry_size;

//       auto const begin = memory_area_container::iterator{&mminfo->entries};
//       auto const end = begin + number_of_entries;
//       return memory_area_container{begin, end};
//     }

//     auto process_elf_sections(elf_symbols_section_header * symbol, std::size_t & kernel_start, std::size_t &
//     kernel_end)
//         -> elf_section_header_container
//     {
//       auto const expected_entry_size = symbol->entry_size;
//       auto constexpr actual_entry_size = sizeof(elf_section_header);
//       exception_handling::assert(expected_entry_size == actual_entry_size,
//                                  "[Multiboot Reader] Unexpected elf section header entry size");

//       auto const expected_total_size = symbol->info.size;
//       auto const actual_total_entry_size = actual_entry_size * symbol->number_of_sections;
//       auto constexpr actual_total_section_size = sizeof(elf_symbols_section_header) - sizeof(uint32_t);
//       auto const actual_total_size = actual_total_entry_size + actual_total_section_size;
//       exception_handling::assert(expected_total_size == actual_total_size,
//                                  "[Multiboot Reader] Unexpected elf symbols section header total size");

//       auto const begin = elf_section_header_container::iterator{reinterpret_cast<elf_section_header
//       *>(&symbol->end)}; auto const end = begin + symbol->number_of_sections;
//       exception_handling::assert(begin->is_null(),
//                                  "[Multiboot Reader] Elf symbols section not starting with SHT_NULL section");

//       elf_section_header_container sections{begin, end};

//       auto allocated_sections = sections | std::views::filter([](auto const & section) {
//                                   return section.flags.contains_flags(elf_section_flags::OCCUPIES_MEMORY);
//                                 });

//       auto const elf_section_with_lowest_physical_address = std::ranges::min_element(
//           allocated_sections, [](auto const & a, auto const & b) { return a.physical_address < b.physical_address;
//           });

//       auto const elf_section_with_highest_physical_address =
//           std::ranges::max_element(allocated_sections, [](auto const & a, auto const & b) {
//             auto a_physical_address_end = a.physical_address + a.section_size;
//             auto b_physical_address_end = b.physical_address + b.section_size;
//             return a_physical_address_end < b_physical_address_end;
//           });

//       auto const symbol_table_section_count = std::ranges::count_if(sections, [](auto const & section) {
//         return section.type == elf_section_type::DYNAMIC_SYMBOL_TABLE || section.type ==
//         elf_section_type::SYMBOL_TABLE;
//       });
//       auto const dynamic_section_count = std::ranges::count_if(
//           sections, [](auto const & section) { return section.type == elf_section_type::DYNAMIC; });

//       exception_handling::assert(
//           symbol_table_section_count == 1U,
//           "[Multiboot Reader] ELF Specifications allows only (1) symbol table section, but got more");
//       exception_handling::assert(
//           dynamic_section_count <= 1U,
//           "[Multiboot Reader] ELF Specifications allows only (1) or less dynamic sections, but got more");

//       auto const lowest_elf_section = *elf_section_with_lowest_physical_address;
//       kernel_start = lowest_elf_section.physical_address;

//       auto const highest_elf_section = *elf_section_with_highest_physical_address;
//       kernel_end = highest_elf_section.physical_address + highest_elf_section.section_size;

//       return sections;
//     }
//   }  // namespace

//   auto read_multiboot2() -> memory_information
//   {
//     memory_information mem_info{UINT64_MAX,
//                                 0U,
//                                 elf_section_header_container{},
//                                 boot::multiboot_information_pointer,
//                                 0U,
//                                 memory_area_container{}};

//     auto const multiboot_information_pointer = reinterpret_cast<info_header *>(boot::multiboot_information_pointer);
//     auto const multiboot_tag = &multiboot_information_pointer->tags;
//     mem_info.multiboot_end = mem_info.multiboot_start + multiboot_information_pointer->total_size;

//     for (auto tag = multiboot_tag; tag->type != tag_type::END; tag = align_to_8_byte_boundary(tag, tag->size))
//     {
//       switch (tag->type)
//       {
//         case tag_type::ELF_SECTIONS: {
//           auto const symbol = reinterpret_cast<elf_symbols_section_header *>(tag);
//           mem_info.sections = process_elf_sections(symbol, mem_info.kernel_start, mem_info.kernel_end);
//           break;
//         }
//         case tag_type::MEMORY_MAP: {
//           auto const mminfo = reinterpret_cast<memory_map_header *>(tag);
//           mem_info.areas = process_memory_map(mminfo);
//           break;
//         }
//         default:
//           // All other cases are not important and can be ignored.
//           break;
//       }
//     }
//     return mem_info;
//   }
// }  // namespace teachos::arch::memory::multiboot