#!/usr/bin/env python

# Transforms a map spreadsheet to use a different root.

# Warning: ch_root is usually *not* an idempotent operation.

import csv

import os.path

import re

import sys

sys.path.append(os.path.dirname(__file__)+"/../lib")

import maps

import opts

def main():

    # Get config from env vars

    env_names = []

    print_usage_ref = [False]

    def on_unset(e): print_usage_ref[0] = True

    configs = [opts.get_env_vars(['in_root', 'out_root'], col, env_names,

        on_unset) for col in ['left', 'right']]

    if print_usage_ref[0]: raise SystemExit(

        'Usage: '+opts.env_usage(env_names)+' '+sys.argv[0]+' <in_map >out_map')

    # Transform map

    reader = csv.reader(sys.stdin)

    writer = csv.writer(sys.stdout)

    cols = reader.next()

    for i in xrange(len(configs)):

        config = configs[i]

        cols[i], config['root'] = maps.col_info(cols[i])[:2]

        if config['root'] != None: cols[i] += ':'+config['out_root']

        else:

            assert config['out_root'] == ''

            config['root'] = ''

        config['in_root_re'] = r'^'+re.escape(config['in_root'])+r'(?=\b|\W|$)'

    writer.writerow(cols)

    for row in reader:

        def sub(i):

            row[i], n = re.subn(configs[i]['in_root_re'], r'',

                configs[i]['root']+row[i])

            return n > 0

        if row[0] != '' and sub(0) and (row[1] == '' or sub(1)):

            writer.writerow(row)

main()