""" TeXcheck.py -- rough syntax checking on Python style LaTeX documents.

   Written by Raymond D. Hettinger <python at rcn.com>
   Copyright (c) 2003 Python Software Foundation.  All rights reserved.

Designed to catch common markup errors including:
* Unbalanced or mismatched parenthesis, brackets, and braces.
* Unbalanced of mismatched \begin and \end blocks.
* Misspelled or invalid LaTeX commands.
* Use of forward slashes instead of backslashes for commands.
* Table line size mismatches (only \lineii used in a tableii).

Command line usage:
    python texcheck.py [-h] [-k keyword] foobar.tex

Options:
    -m          Munge parenthesis and brackets. [0,n) would normally mismatch.
    -k keyword: Keyword is a valid LaTeX command. Do not include the backslash.
    -d:         Delimiter check only (useful for non-LaTeX files).
    -h:         Help
    -s lineno:  Start at lineno (useful for skipping complex sections).
    -v:         Verbose.  Shows current delimiter and unclosed delimiters.
"""

import re
import sets
import sys
import getopt
from itertools import izip, count, islice

cmdstr = r"""
    \section \module \declaremodule \modulesynopsis \moduleauthor
    \sectionauthor \versionadded \code \class \method \begin
    \optional \var \ref \end \subsection \lineiii \hline \label
    \indexii \textrm \ldots \keyword \stindex \index \item \note
    \withsubitem \ttindex \footnote \citetitle \samp \opindex
    \noindent \exception \strong \dfn \ctype \obindex \character
    \indexiii \function \bifuncindex \refmodule \refbimodindex
    \subsubsection \nodename \member \chapter \emph \ASCII \UNIX
    \regexp \program \production \token \productioncont \term
    \grammartoken \lineii \seemodule \file \EOF \documentclass
    \usepackage \title \input \maketitle \ifhtml \fi \url \Cpp
    \tableofcontents \kbd \programopt \envvar \refstmodindex
    \cfunction \constant \NULL \moreargs \cfuncline \cdata
    \textasciicircum \n \ABC \setindexsubitem \versionchanged
    \deprecated \seetext \newcommand \POSIX \pep \warning \rfc
    \verbatiminput \methodline \textgreater \seetitle \lineiv
    \funclineni \ulink \manpage \funcline \dataline \unspecified
    \textbackslash \mimetype \mailheader \seepep \textunderscore
    \longprogramopt \infinity \plusminus \shortversion \version
    \refmodindex \seerfc \makeindex \makemodindex \renewcommand
    \indexname \appendix \protect \indexiv \mbox \textasciitilde
    \platform \seeurl \leftmargin \labelwidth \localmoduletable
    \LaTeX \copyright \memberline \backslash \pi \centerline
    \caption \vspace \textwidth \menuselection \textless
    \makevar \csimplemacro \menuselection \bfcode \sub \release
    \email \kwindex \refexmodindex \filenq \e \menuselection
    \exindex \linev \newsgroup \verbatim \setshortversion
"""

def matchclose(c_lineno, c_symbol, openers, pairmap):
    "Verify that closing delimiter matches most recent opening delimiter"
    try:
        o_lineno, o_symbol = openers.pop()
    except IndexError:
        msg = "Delimiter mismatch.  On line %d, encountered closing '%s' without corresponding open" % (c_lineno, c_symbol)
        raise Exception, msg
    if o_symbol in pairmap.get(c_symbol, [c_symbol]): return
    msg = "Opener '%s' on line %d was not closed before encountering '%s' on line %d" % (o_symbol, o_lineno, c_symbol, c_lineno)
    raise Exception, msg

def checkit(source, opts, morecmds=[]):
    """Check the LaTeX formatting in a sequence of lines.

    Opts is a mapping of options to option values if any:
        -m          munge parenthesis and brackets
        -d          delimiters only checking
        -v          verbose listing of delimiters
        -s lineno:  linenumber to start scan (default is 1).

    Morecmds is a sequence of LaTeX commands (without backslashes) that
    are to be considered valid in the scan.
    """

    texcmd = re.compile(r'\\[A-Za-z]+')
    falsetexcmd = re.compile(r'\/([A-Za-z]+)') # Mismarked with forward slash

    validcmds = sets.Set(cmdstr.split())
    for cmd in morecmds:
        validcmds.add('\\' + cmd)

    if '-m' in opts:
        pairmap = {']':'[(', ')':'(['}      # Munged openers
    else:
        pairmap = {']':'[', ')':'('}        # Normal opener for a given closer
    openpunct = sets.Set('([')  # Set of valid openers

    delimiters = re.compile(r'\\(begin|end){([_a-zA-Z]+)}|([()\[\]])')
    braces = re.compile(r'({)|(})')

    openers = []                            # Stack of pending open delimiters
    bracestack = []                         # Stack of pending open braces

    tablestart = re.compile(r'\\begin{(?:long)?table([iv]+)}')
    tableline = re.compile(r'\\line([iv]+){')
    tableend = re.compile(r'\\end{(?:long)?table([iv]+)}')
    tablelevel = ''
    tablestartline = 0

    startline = int(opts.get('-s', '1'))
    lineno = 0

    for lineno, line in izip(count(startline), islice(source, startline-1, None)):
        line = line.rstrip()

        if '/' in line and '-d' not in opts:
            # Warn whenever forward slashes encountered with a LaTeX command
            for cmd in falsetexcmd.findall(line):
                if '\\' + cmd in validcmds:
                    print 'Warning, forward slash used on line %d with cmd: /%s' % (lineno, cmd)

        if '-d' not in opts:
            # Validate commands
            nc = line.find(r'\newcommand')
            if nc != -1:
                start = line.find('{', nc)
                end = line.find('}', start)
                validcmds.add(line[start+1:end])
            for cmd in texcmd.findall(line):
                if cmd not in validcmds:
                    print r'Warning, unknown tex cmd on line %d: \%s' % (lineno, cmd)

        # Check balancing of open/close parenthesis and brackets
        for begend, name, punct in delimiters.findall(line):
            if '-v' in opts:
                print lineno, '|', begend, name, punct,
            if begend == 'begin' and '-d' not in opts:
                openers.append((lineno, name))
            elif punct in openpunct:
                openers.append((lineno, punct))
            elif begend == 'end' and '-d' not in opts:
                matchclose(lineno, name, openers, pairmap)
            elif punct in pairmap:
                matchclose(lineno, punct, openers, pairmap)
            if '-v' in opts:
                print '   --> ', openers

        # Balance opening and closing braces
        for open, close in braces.findall(line):
            if open == '{':
                bracestack.append(lineno)
            if close == '}':
                try:
                    bracestack.pop()
                except IndexError:
                    print r'Warning, unmatched } on line %s.' % (lineno,)
            if '-v' in opts:
                print '   --> ', bracestack

        # Check table levels (make sure lineii only inside tableii)
        m = tablestart.search(line)
        if m:
            tablelevel = m.group(1)
            tablestartline = lineno
        m = tableline.search(line)
        if m and m.group(1) != tablelevel:
            print r'Warning, \line%s on line %d does not match \table%s on line %d' % (m.group(1), lineno, tablelevel, tablestartline)
        if tableend.search(line):
            tablelevel = ''

    lastline = lineno
    for lineno, symbol in openers:
        print "Unmatched open delimiter '%s' on line %d" % (symbol, lineno)
    for lineno in bracestack:
        print "Unmatched { on line %d" % (lineno,)
    print 'Done checking %d lines.' % (lastline,)
    return 0

def main(args=None):
    if args is None:
        args = sys.argv[1:]
    optitems, arglist = getopt.getopt(args, "k:mdhs:v")
    opts = dict(optitems)
    if '-h' in opts or args==[]:
        print __doc__
        return 0

    if len(arglist) < 1:
        print 'Please specify a file to be checked'
        return 1

    morecmds = [v for k,v in optitems if k=='-k']

    try:
        f = open(arglist[0])
    except IOError:
        print 'Cannot open file %s.' % arglist[0]
        return 2

    return(checkit(f, opts, morecmds))

if __name__ == '__main__':
    sys.exit(main())