<script>
    /**
     * Week 2 election project sample solution by Jake
     */

    // Class modelling a member of the population who votes in the election.
    class Voter {
        constructor(name, age, vote) {
            this.name = name;
            this.age = age;
            this.vote = vote;
        }

        static validVote(vote) {
            if (vote.length !== 2) return false;
            return true;
        }
    }

    // Class modelling a candidate in the election. Candidates are also voters (they can vote for themselves, or anyone else).
    // However they have some extra properties; the number of votes they receive and the party they belong to.
    class Candidate extends Voter {
        constructor(name, age, party) {
            super(name, age);
            this.name = name;
            this.age = age;
            this.party = party;
            this.numVotes = 0;
        }
    }


    // The class which models the election event. An election consists of a voting population, a list of candidates and a winning candidate.
    // voters should be an object whose keys are candidate IDs, and values are the Candidate objects themselves.
    class Election {
        constructor(voters, candidates) {
            this.voters = voters;
            this.candidates = candidates;
            this.winner = null;
        }

        // After an election has been run, get the winner and store in this.winner.
        // This method is private and shouldn't be accessed outside the class.
        _getWinner() {
            let highestNumVotes = 0;
            let currentCandidate = null;

            Object.keys(this.candidates).forEach(candidateId => {
                let numVotes = this.candidates[candidateId].numVotes;
                if (highestNumVotes < numVotes) {
                    highestNumVotes = numVotes;
                    currentCandidate = this.candidates[candidateId];
                }
            });
            this.winner = currentCandidate;
        }

        // Tally up all the votes from the population of voters stored in this.voters. For each iteration of a voter, a new loop is required
        // to iterate over the votes cast by the voter. For two adjacent votes in the array, the right vote has half the weight of the left.
        runElection() {
            this.voters.forEach(voter => {
                let vote = voter.vote;
                let weight = 1;

                vote.forEach(candidateId => {
                    this.candidates[candidateId].numVotes += weight;
                    weight /= 2;
                });
            });
            this._getWinner();
        }
    }

    // A sample population of a small number of voters, stored as an array
    let votingPopulation = [
        new Voter('Jane Finnegan', 19, [1,3]),
        new Voter('Norman Beracha', 35, [3,4]),
        new Voter('Salome Kadek', 22, [2,1,3]),
        new Voter('Wei Li', 19, [1,2]),
        new Voter('Sam MacKinnon', 59, [1,4])
    ];

    // The election candidates, stored as an object where each object key is the candidate ID, and the object
    // value is the candidate object itself.
    let candidates = {
        1: new Candidate('Tamara Faiza', 46, 'Pizza Party'),
        2: new Candidate('Aylin Duke', 39, 'Foam Party'),
        3: new Candidate('Clay Roderick', 54, 'Flat Earth Party'),
        4: new Candidate('Nour al-Din', 32, 'Pizza Party'),
    };

    let validVoters = votingPopulation.filter(voter => Voter.validVote(voter.vote));

    let election = new Election(validVoters, candidates);

    election.runElection();

    let winner = election.winner;

    console.log(winner.name + " has won with " + winner.numVotes + " votes.");
</script>