#include "kernel/filesystem/ext2/ext2_filesystem.hpp"

#include "kernel/devices/block_device_utils.hpp"
#include "kernel/devices/device.hpp"
#include "kernel/filesystem/ext2/ext2_inode.hpp"
#include "kernel/filesystem/ext2/ext2_superblock.hpp"
#include "kernel/filesystem/filesystem.hpp"
#include "kernel/filesystem/inode.hpp"

#include <kstd/memory>

#include <cstddef>
#include <cstdint>
#include <string_view>

namespace filesystem::ext2
{
  namespace
  {
    constexpr size_t SUPERBLOCK_OFFSET = 1024;
    constexpr uint16_t EXT2_MAGIC = 0xEF53;

    // Mode bits
    constexpr uint16_t S_IFMT = 0xF000;
    constexpr uint16_t S_IFREG = 0x8000;
    constexpr uint16_t S_IFDIR = 0x4000;

    auto S_ISREG(uint16_t mode) -> bool
    {
      return (mode & S_IFMT) == S_IFREG;
    }
    auto S_ISDIR(uint16_t mode) -> bool
    {
      return (mode & S_IFMT) == S_IFDIR;
    }

    auto get_block_size(ext2_superblock const & superblock) -> size_t
    {
      return 1024U << superblock.log_block_size;
    }

    auto get_inode_size(ext2_superblock const & superblock) -> size_t
    {
      return superblock.rev_level == 0 ? 128 : superblock.inode_size;
    }
  }  // namespace

  auto ext2_filesystem::mount(kstd::shared_ptr<devices::device> const & device) -> int
  {
    filesystem::mount(device);  // TODO BA-FS26 error handling?
    // TODO BA-FS26 load proper root inode from ext2 metadata
    // m_root_inode = inode{inode_kind::directory};

    // TODO BA-FS26 implement
    m_root_inode = kstd::make_shared<ext2_inode>();
    // devices::block_device_utils::read(device, nullptr, 0, 0);  // TODO BA-FS26 just for testing
    return 0;
  }

  auto ext2_filesystem::lookup(kstd::shared_ptr<inode> const & /*parent*/, std::string_view name)
      -> kstd::shared_ptr<inode>
  {
    // TODO BA-FS26 implement ext2 directory traversal and inode loading
    if (name == "dev")
    {
      // TODO BA-FS26 just for testing
      return nullptr;
    }

    return kstd::make_shared<ext2_inode>();
  }
}  // namespace filesystem::ext2