#include "fs/ext2/inode_table.h"

#include <mammoth/debug.h>

InodeTable::InodeTable(Ext2BlockReader& reader, BlockGroupDescriptor* bgdt)
    : ext2_reader_(reader), bgdt_(bgdt) {
  inode_tables_.Resize(ext2_reader_.NumberOfBlockGroups());
}

glcr::ErrorOr<Inode*> InodeTable::GetInode(uint64_t inode_num) {
  uint64_t inodes_per_group = ext2_reader_.GetSuperblock()->inodes_per_group;
  uint64_t block_group_num = (inode_num - 1) / inodes_per_group;
  ASSIGN_OR_RETURN(Inode * root, GetRootOfInodeTable(block_group_num));
  uint64_t local_index = (inode_num - 1) % inodes_per_group;
  return reinterpret_cast<Inode*>(reinterpret_cast<uint64_t>(root) +
                                  local_index * ext2_reader_.InodeSize());
}

glcr::ErrorOr<Inode*> InodeTable::GetRootOfInodeTable(
    uint64_t block_group_num) {
  if (block_group_num > ext2_reader_.NumberOfBlockGroups()) {
    return glcr::INVALID_ARGUMENT;
  }

  if (!inode_tables_[block_group_num]) {
    ASSIGN_OR_RETURN(
        inode_tables_[block_group_num],
        ext2_reader_.ReadBlocks(bgdt_[block_group_num].inode_table,
                                ext2_reader_.InodeTableBlockSize()));
  }
  return reinterpret_cast<Inode*>(inode_tables_[block_group_num].vaddr());
}