#!/usr/bin/env python3

import argparse
import csv
import requests
import os

from io import StringIO

from dotenv import load_dotenv

def get_votes(ids):
    votes = {}
    for id in ids:
        res = requests.get(os.environ['API_VOTE'].format(question_id=id), headers={'Authorization': 'Bearer ' + os.environ['BEARER']})
        if not res.ok:
            print('Could not get votes for id', id)
            continue
        f = StringIO(res.text)
        reader = csv.DictReader(f)
        for row in reader:
            votes.setdefault(row['Delegation'], []).append(row['Option'])
    return list(votes.values())

def get_candidates_from_votes(votes):
    candidates = set()
    for vote in votes:
        for option in vote:
            candidates.add(option)
    return candidates

def determine_winners(people, votes):
    """Single Transferable Vote (https://en.wikipedia.org/wiki/Single_transferable_vote)"""
    elected = []
    elected_set = set()
    candidates = get_candidates_from_votes(votes)
    surplus_votes = {x: 0 for x in candidates}
    quota = len(votes) / people + 1

    print('Votes:', len(votes))
    print('Quota:', quota)
    print('Candidates:', len(candidates))

    def one_round():
        print('-----------')
        print('Start Round')
        print('-----------')
        round_votes = {x: 0 for x in candidates}
        for vote in votes:
            vote_weight = 1
            for option in vote:
                if option in elected_set:
                    vote_weight *= surplus_votes[option]
                if option in candidates and option not in elected_set:
                    round_votes[option] += vote_weight
                    break
        vote_counts = []
        for candidate in candidates:
            if candidate in elected_set:
                continue
            vote_counts.append((round_votes[candidate], candidate))
        vote_counts.sort()
        print('Vote counts:')
        for (count, candidate) in reversed(vote_counts):
            print('  {}: {}'.format(candidate, count))
        if vote_counts[-1][0] >= quota or len(candidates) == people:
            elected.append((vote_counts[-1][1], vote_counts[-1][0]))
            elected_set.add(vote_counts[-1][1])

            surplus = vote_counts[-1][0] - quota
            if surplus > 0:
                surplus_votes[vote_counts[-1][1]] = surplus / vote_counts[-1][0]

            print('Elect', vote_counts[-1][1])
        elif len(candidates) > people:
            candidates.remove(vote_counts[0][1])
            print('Remove', vote_counts[0][1])

    while len(elected_set) < people:
        one_round()

    return elected

def test_votes():
    return [
        ['O'],
        ['O'],
        ['O'],
        ['O'],
        ['P', 'O'],
        ['P', 'O'],
        ['C', 'S'],
        ['C', 'S'],
        ['C', 'S'],
        ['C', 'S'],
        ['C', 'S'],
        ['C', 'S'],
        ['C', 'S'],
        ['C', 'S'],
        ['C', 'H'],
        ['C', 'H'],
        ['C', 'H'],
        ['C', 'H'],
        ['S'],
        ['H'],
    ]

def main():
    load_dotenv('secrets.env')
    parser = argparse.ArgumentParser(description='Determine voted persons from list of votes.')
    parser.add_argument('--test', action='store_true', help='Use test values for the votes')
    parser.add_argument('people', type=int, help='Number of people who need to be voted.')
    parser.add_argument('questions', type=int, nargs='+', help='IDs of the questions.')
    args = parser.parse_args()
    if args.test:
        votes = test_votes()
    else:
        votes = get_votes(args.questions)
    winners = determine_winners(args.people, votes)

    print('-------------')
    print('Final results')
    print('-------------')
    for i, (winner, votes) in enumerate(winners):
        print('{:2} with {:2} votes: {}'.format(i+1, int(votes), winner))

if __name__ == '__main__':
    main()