#include <kernel/filesystem/open_file_descriptor.hpp>

#include <kernel/filesystem/dentry.hpp>

#include <kstd/memory>
#include <kstd/os/error.hpp>

#include <cstddef>

namespace kernel::filesystem
{
  open_file_descriptor::open_file_descriptor(kstd::shared_ptr<dentry> const & dentry)
      : m_dentry(dentry)
      , m_offset(0)
  {
    if (!dentry)
    {
      kstd::os::panic("[FILESYSTEM] open_file_descriptor constructed with null dentry.");
    }
  }

  auto open_file_descriptor::read(void * buffer, size_t size) -> size_t
  {
    auto read_bytes = m_dentry->get_inode()->read(buffer, m_offset, size);
    m_offset += read_bytes;
    return read_bytes;
  }

  auto open_file_descriptor::write(void const * buffer, size_t size) -> size_t
  {
    auto written_bytes = m_dentry->get_inode()->write(buffer, m_offset, size);
    m_offset += written_bytes;
    return written_bytes;
  }

  auto open_file_descriptor::offset() const -> size_t
  {
    return m_offset;
  }

}  // namespace kernel::filesystem