#! /usr/bin/python3
# Last edited on 2026-01-22 11:44:54 by stolfi

# Library function that reads the star property table of the SPS.
# To be imported by python programs.

from process_funcs import basic_line_loop
import re, sys
from sys import stderr as err

def read_table(fname):
  # Reads the contents of the star property from file {fname}. 
  # 
  # Blank lines and #-comments in file {fname} are ignored.
  #
  # There should be a line starting with "PAGE " that is the header
  # for the table, and one staring with "---" that is the dashes
  # for that header.
  #
  # The other lines must have the format "{fnum} | S{nn} | {props}"
  # where {fnum} is a page's f-number, "S{nn}" is the code of a star
  # from that page (where {nn} is the star number {snum} as two digits,
  # starting from "01") and {props} is the star properties, in any
  # format.
  # 
  # Returns strings {hdr1,hdr2} and dict {tbl}, where {tbl[fnum][snum-1] is
  # the table line for "S{snum}" from the page whose f-number is
  # {fnum}, and {hdr1,hdr2} are the table header and dash line. 
  # 
  # For now, the description of a star is a single string, unparsed.
  
  tbl = dict()
  fnum_cur = None
  last_snum = None
  hdr1 = None
  hdr2 = None
  
  def process_line(nread, line):
    nonlocal tbl, fnum_cur, last_snum, hdr1, hdr2
    line = line.strip()
    if re.match(r"^[ \011]*([#]|$)", line): return
    if re.match(r"PAGE ", line):
      hdr1 = line; return
    if re.match(r"[-][-][-]", line):
      hdr2 = line; return
    m = re.fullmatch(r"(f[0-9a-z]+)[ ]*[|][ ]*(S[0-9][0-9])[ ]*[|][ ](.*)", line)
    if m == None:
      err.write(f"{fname}:{nread}: ** invalid line format\n  [[{line}]]\n")
      sys.exit(1)
    fnum, Snn, props = m.group(1,2,3)
    if fnum != fnum_cur:
      if fnum in tbl:
        err.write(f"{fname}:{nread}: ** repeated page = {fnum}\n  [[{line}]]\n")
        sys.exit(1)
      tbl[fnum] = []
      fnum_cur = fnum
      last_snum = 0
    snum = int(Snn[1:])
    if snum != last_snum + 1:
      err.write(f"{fname}:{nread}: ** unexpected star number = {Snn}\n  [[{line}]]\n")
      sys.exit(1)
    tbl[fnum].append(line)
    last_snum = snum
    return
    # ....................................................................
    
  rd = open(fname, "r")
  nread = basic_line_loop(rd, process_line)
  if len(tbl) == 0:
    err.write(f"{fname}:{nread}: ** no entries in table file {fname}\n [[{line}]]\n")
    sys.exit(1)
  rd.close()
  return hdr1, hdr2, tbl
  # ----------------------------------------------------------------------