#!/usr/bin/env python
'''
th2svx - Convert Therion .th files to Survex .svx format

Copyright (C) 2007 David A. Riggs <david.a.riggs@gmail.com>

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, see:

http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
'''

import sys

USAGE = '''
usage: th2svx FILE ...

Convert Therion .th files to Survex .svx format.
'''


def convert_filename(fname):
    '''convert_filename(foo.th) -> foo.svx'''
    return fname[:fname.rindex('.')] + '.svx'


def get_indent(line):
    '''return the indentation whitespace from a line of text'''
    chars = len(line) - len(line.lstrip())
    return line[:chars]


def convert_line(line):
    indent = get_indent(line)
    outline = line.strip()

    # these commands or tokens are different in therion vs. survex
    replacements = ('#', ';'), ('survey', '*begin'), ('endsurvey', '*end'), ('input', '*include'), ('encoding', '; encoding')
    for k,v in replacements:
        if outline.startswith(k):
            outline = v + outline[len(k):]

    # these are identical commands, just need prepended with '*'
    commands = ('calibrate', 'data', 'date', 'equate', 'fix', 'flags', 'team', 'title', 'units')
    for command in commands:
        if outline.startswith(command):
            outline = '*'+outline

    # replace all comment characters, anywhere (dumb op)
    outline = outline.replace('#',';')

    # replace -title option with command (uses newline, must be final op!)
    outline = outline.replace('-title', '\n'+indent+'*title')

    return indent + outline


def th2svx(f):
    '''convert a file from therion .th to survex .svx'''
    infile = open(f)
    outfile = open(convert_filename(f), 'w')
    for line in infile:
        outline = convert_line(line)
        print >> outfile, outline


def main():
    files = sys.argv[1:]
    
    if not files or files[0] == '--help':
        print >> sys.stderr, USAGE
        exit(2)
        
    for f in files:
        th2svx(f)


if __name__ == '__main__':
    main()