#!/usr/bin/env python3

## csv_to_ln: Convert a comma separated values file into one parseable by
## LabelNation.
##
## Copyright (C) 2008 The Anonymous Text Crank <anontextcrank@gmail.com>
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## 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, write to the Free Software
## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

import sys
import csv
import re
if sys.hexversion < 0x3000000:
    sys.stderr.write("ERROR: Python 3.0 or higher required, "
                     "see www.python.org.\n")
    sys.exit(1)

from optparse import OptionParser

def explain():
    """An explanation of what this script expects and does."""
    print("""csv_to_ln converts "comma separated value" (csv) files into a format that is
readable by LabelNation.

The csv format is a fairly common text format, and most spreadsheets and
databases can easily export their data to csv format. The format that csv_to_ln
expects is fairly standard:

  0) There is one record per line; each record is a sequence of fields.

  1) Each field is enclosed is a pair of quotation marks ("'s). Two consecutive
  quotation marks escapes to a single quotation mark. See the example below.

  2) Each field is separated from the next field by a single comma
     (NO whitespace between the comma and the next quotation mark).

  3) There is no trailing comma at the end of the line.

The basic idea of csv_to_ln is to convert each record into a series of lines,
adding a line consisting of a delimeter string (settable with the --delimiter
option. The default is "XXX") between records. This is the format of the file
examples/multipage.txt included in the LabelNation tarball. As the labelnation
script is sensitive to leading whitespace, csv_to_ln allows the user to add a
constant number of whitespaces before each field through the --num_spaces
option.

EXAMPLE
-------

Let us suppose that we have the file addresses.csv, which has contents

  "Ernest and Bertrand Muppet","123 Sesame Street","New York, NY 11123"
  "Elvis ""The King"" Presley","222 N. Danny Thomas Boulevard","Memphis, TN 37522"
  "Georgia O'Keefe","The Art Institute of Chicago","111 South Michigan Avenue","Chicago, IL 60603-6404"

We make a call to csv_to_ln:

  prompt$ csv_to_ln --delimiter="#####" --num_spaces=4 --outfile=addresses.txt addresses.csv

Now that the output file has been generated, a typical call to LabelNation
might be something like

  labelnation --infile addresses.txt --line-input --delimiter="#####" --type=avery5167

If it wasn't immediately obvious, it should be now that it is important to use
the same delimiter as was used in csv_to_ln to generate the output file
(addresses.txt). Depending on what you choose as a delimiter, you may need to
escape it with double or single quotes so as not to be interpreted by the
shell.
""")

def main():
    usage = "usage: %prog [options] csv_file"
    parser = OptionParser(usage)
    parser.add_option("-d", "--delimiter", default="XXX", metavar="DELIM",
                      help="Use DELIM to separate records in the output.")
    parser.add_option("-n", "--num_spaces", type="int", default=3, metavar="N",
                      help="Put N spaces before each output line")
    parser.add_option("-o", "--outfile", metavar="OUTFILE",
                      help="Write output to OUTFILE. Default is standard output")
    parser.add_option("-e", "--explain", action="store_true", default=False,
                      help="Print extensive explantion about how this program works.")

    (options, args) = parser.parse_args()

    if options.explain:
        explain()
        parser.print_help()
        sys.exit(0)

    if len(args) != 1:
        parser.error("""You must supply an input filename.

Try csv_to_ln --help or --explain for more information""")
    else:
        csv_file = args[0]
        if not options.outfile:
            f_out = sys.stdout
        else:
            f_out = open(options.outfile, 'w')

    spaces = " " * options.num_spaces
    newline = '\n'
    reader = csv.reader(open(csv_file, "r"))

    for row in reader:
        for line in row:
            f_out.write(spaces + line + newline)
        f_out.write(options.delimiter + newline)

if __name__ == "__main__":
     main()