"""
trainling_spaces - checker for vxnorm

This file does not expose an explicite VxChecker object declaration to avoid
dependencies handling, you just need to provide:
    ======================= ===============================================
    parse_file()            Parse the source file
    ======================= ===============================================
"""

#---
# Public
#---

def parse_file(checker, mfile, _):
    """ parse the mapped file

    The file is mapped using mmap() and seeked through offset 0 to avoid too
    many I/O operations with classical file primitive.

    @args
    > checker (VxChecker) - current checker instance for this file
    > mfile        (mmap) - mmap instance of the file, seeked at 0
    > pathname      (str) - file pathname

    @return
    > Nothing
    """
    counter = 0
    checker.select_rule('trailing')
    for line in mfile.getlines():
        counter += 1
        line_end = len(line) - 1
        line_end = line_end - (line[line_end] == '\n')
        if line_end <= 0:
            continue
        for i in range(line_end, 0, -1):
            if not line[i].isspace():
                break
        if i != line_end:
            checker.notify(
                f"{counter}:{i+1}",
                f"trailing space at ({i+1} != {line_end})",
            )