import copy
def preprocess(example):

  def _add_adjusted_col_offsets(table):
    """Add adjusted column offsets to take into account multi-column cells."""
    adjusted_table = []
    for row in table:
      real_col_index = 0
      adjusted_row = []
      for cell in row:
        adjusted_cell = copy.deepcopy(cell)
        adjusted_cell["adjusted_col_start"] = real_col_index
        adjusted_cell["adjusted_col_end"] = (
            adjusted_cell["adjusted_col_start"] + adjusted_cell["column_span"])
        real_col_index += adjusted_cell["column_span"]
        adjusted_row.append(adjusted_cell)
      adjusted_table.append(adjusted_row)
    return adjusted_table


  def _get_heuristic_row_headers(adjusted_table, row_index, col_index):
    """Heuristic to find row headers."""
    row_headers = []
    row = adjusted_table[row_index]
    for i in range(0, col_index):
      if row[i]["is_header"]:
        row_headers.append(row[i])
    return row_headers


  def _get_heuristic_col_headers(adjusted_table, row_index, col_index):
    """Heuristic to find column headers."""
    adjusted_cell = adjusted_table[row_index][col_index]
    adjusted_col_start = adjusted_cell["adjusted_col_start"]
    adjusted_col_end = adjusted_cell["adjusted_col_end"]
    col_headers = []
    for r in range(0, row_index):
      row = adjusted_table[r]
      for cell in row:
        if (cell["adjusted_col_start"] < adjusted_col_end and
            cell["adjusted_col_end"] > adjusted_col_start):
          if cell["is_header"]:
            col_headers.append(cell)

    return col_headers


  
  table = example['table']
  cell_indices = example["highlighted_cells"]
  table_str = ""
  if example['table_page_title']:
    table_str += "<page_title> " + example['table_page_title'] + " </page_title> "
  if example['table_section_title']:
    table_str += "<section_title> " + example['table_section_title'] + " </section_title> "

  table_str += "<table> "
  adjusted_table = _add_adjusted_col_offsets(table)
  for r_index, row in enumerate(table):
    row_str = "<row> "
    for c_index, col in enumerate(row):

      row_headers = _get_heuristic_row_headers(adjusted_table, r_index, c_index)
      col_headers = _get_heuristic_col_headers(adjusted_table, r_index, c_index)

      # Distinguish between highlighted and non-highlighted cells.
      if [r_index, c_index] in cell_indices:
        start_cell_marker = "<highlighted_cell> "
        end_cell_marker = "</highlighted_cell> "
      else:
        start_cell_marker = "<c> "
        end_cell_marker = "</c> "

      # The value of the cell.
      item_str = start_cell_marker + col["value"] + " "

      # All the column headers associated with this cell.
      for col_header in col_headers:
        item_str += "<col_header> " + col_header["value"] + " </col_header> "

      # All the row headers associated with this cell.
      for row_header in row_headers:
        item_str += "<row_header> " + row_header["value"] + " </row_header> "

      item_str += end_cell_marker
      row_str += item_str

    row_str += "</row> "
    table_str += row_str

  table_str += "</table>"

  example['linearized_table'] = <s>' + table_str + '\n' + '\n'
  return example