whatif.py

#!/usr/bin/env python3
#
#####
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#####

# Run alternate voting scenarios: vary the number of seats, remove candidates,
# or do a run-off with only the specified candidates.  Candidate names can
# be specified using either their first name, last name, or full name without
# any spaces (independent of case).  Examples:
#
# Examples:
#   whatif.py ../Meetings/20110712/raw_board_votes.txt 10
#   whatif.py ../Meetings/20110712/raw_board_votes.txt -LawrenceRosen
#   whatif.py ../Meetings/20110712/raw_board_votes.txt 1 kulp noirin geir chris

import sys
if __name__ != '__main__':
    raise Exception('ERROR: not intended to be used as a library.')

import os.path
import re
import pathlib
import json

THIS_SCRIPT = pathlib.Path(__file__).resolve()
THIS_DIR = THIS_SCRIPT.parent

# We're a top-level script. Adjust the import path.
sys.path.append(str(THIS_DIR / 'monitoring'))
import stv_tool


def usage():
    print(f'Usage: {THIS_SCRIPT.name} [-v] RAW_VOTES_FILE [seats] [-]name...')
    sys.exit(1)


def load_votedata(votefile):
    "Accept multiple variants of the vote file. Return NAMES, VOTESTRINGS."

    if votefile.endswith('.json'):
        # Presume this is a v3 json file. (prior ones are useless, it seems)

        jvalue = json.load(open(votefile))
        labelmap, votestrings = stv_tool.load_v3(jvalue)

        # Construct a label-sorted list of names from the labelmap.
        names = [name for _, name in sorted(labelmap.items())]

        return names, votestrings

    # Assume raw_board_votes.txt
    return stv_tool.load_votes(votefile)  # returns names, list of vote-lists


### NOTE: whatif.rb has an expectation of our argument format and
### sequencing. Stick to that for now. ... One day: argparse.


# Get rid of the script name.
_ = sys.argv.pop(0)

if sys.argv and sys.argv[0] == '-v':
    ### would be nice to pass this, but ... nope.
    stv_tool.VERBOSE = True
    sys.argv.pop(0)

# extract required vote file argument, and load votes from it
if not sys.argv or not os.path.exists(sys.argv[0]): usage()
names, votes = load_votedata(sys.argv.pop(0))

# extract optional number of seats argument
if sys.argv and sys.argv[0].isdigit():
    seats = int(sys.argv.pop(0))
else:
    seats = 9

# extract an alias list of first, last, and joined names
alias = {}
for name in names:
    lname = re.sub(r'[^\w ]', '', name.lower())
    alias[lname.replace(' ', '')] = name
    for part in lname.split(' '):
        alias[part] = name

# validate input
for arg in sys.argv:
    if arg.lstrip('-').lower() not in alias:
        sys.stderr.write('invalid selection: %s\n' % arg)
        usage()

if not sys.argv:
    # no changes to the candidates running
    pass
elif sys.argv[0][0] == '-':
    # remove candidates from vote
    for name in sys.argv: names.remove(alias[name.lstrip('-').lower()])
else:
    # only include specified candidates
    # NOTE: order is important, so sort the names for repeatability
    names = [ alias[n.lower()] for n in sorted(sys.argv) ]

# Trim the raw votes based on cmdline params. Eliminate votes that
# are not for one of the allowed names. Do not include voters who
# did not vote for anybody [post-trimming].
trimmed = [ ]
for voteseq in votes:
    newseq = [ v for v in voteseq if v in names ]
    if newseq:
        trimmed.append(newseq)

# run the vote
candidates = stv_tool.run_stv(names, trimmed, seats)
candidates.print_results()
print('Done!')