#!/usr/bin/env python

# Combines two map spreadsheets A0->B and A1->C to A->B, with A0 overwriting A1

import csv

import maps

    try: _prog_name, map_1_path = sys.argv

    except ValueError:

        raise SystemExit('Usage: '+sys.argv[0]+' <map_0 map_1 [| '+sys.argv[0]

            +' map_2]... >union_map')

    map_ = {}

    def add_map(reader):

        for row in reader:

                try: new = map_[row[0]]

                except KeyError: new = row

                else: new = maps.merge_mappings(new, row)

                map_[row[0]] = new

    # Get map 1

    stream = open(map_1_path, 'rb')

    reader = csv.reader(stream)

    map_1_cols = reader.next()

    add_map(reader)

    stream.close()

    # Add map 0 to map 1, overwriting existing entries

    reader = csv.reader(sys.stdin)

    map_0_cols = reader.next()

    add_map(reader)

    # Write combined map

    writer = csv.writer(sys.stdout)

    for row in map_.itervalues(): writer.writerow(row)

main()