function HandScorer() {

    function score(hand) {
        var matches = {},
            handByNumber = matchingNumbers(hand),
            handBySuit = matchingSuits(hand);

        scorers.forEach(function (scorer) {
            scorer(hand, handByNumber, handBySuit, matches);
        });

        return matches;
    }

    var matchingNumbers = matcherBuilder(function (card) {
        return card.number()
    });
    var matchingSuits = matcherBuilder(function (card) {
        return card.suit()
    });

    var fourOfAKind = nOfNumber(4, 'four of a kind');
    var threeOfAKind = nOfNumber(3, '3 of a kind');
    var twoOfAKind = nOfNumber(2, '2 of a kind');
    var onePair = nOfNumber(2, '2 of a kind');

    var fullHouse = function (hand, handByNumber, handByType, matches) {
        if (matches['three of a kind'].length && matches['three of a kind'].length) {
            matches['full house'] = {
                'three of a kind': matches['three of a kind'],
                'two of a kind': matches['two of a kind']
            }
        }
    };

    var straight = function (hand, handByNumber, handByType, matches) {
        var sequential = [];
        var previous;
        Object.keys(handByNumber).map(function (number) {
            return parseInt(number)
        }).sort()
            .forEach(function (number) {
                if (previous && (previous + 1) == number) {
                    sequential.push(number)
                } else {
                    sequential = [number]
                }
                previous = number;
            });
        return matches['straight'] = sequential;
    };

    var flush = function (hand, handByNumber, handBySuit, matches) {
        return matches['flush'] = Object.keys(handBySuit).reduce(function (matching, card) {
            if (handBySuit[card] == 5) {
                matching.push(card)
            }
        }, [])
    };

    function nOfNumber(n, name) {
        return function (hand, handByNumber, handByType, matches) {
            matches[name] = Object.keys(handByNumber).reduce(function (matching, card) {
                if (handByNumber[card] == n) {
                    matching.push(card)
                }
            }, [])
        }
    }

    function matcherBuilder(criteriaResolver) {
        return function (hand) {
            return hand
                .map(criteriaResolver)
                .reduce(function (matches, card) {
                    matches[card] = (matches[card] || 0) + 1;
                    return matches;
                }, {});
        }
    }

    var scorers = [fourOfAKind, threeOfAKind, twoOfAKind, onePair, fullHouse, straight, flush];

    return {score: score}
}

HandScorer.types = {
    ROYAL_FLUSH: 'royal flush',
    STRAIGHT_FLUSH: 'straight flush',
    FOUR: 'four of  a kind',
    FULL_HOUSE: 'full house',
    FLUSH: 'flush',
    STRAIGHT: 'straight',
    THREE: 'three of a kind',
    TWO: 'two of a kind',
    ONE: 'one of a kind',
    HIGH: 'high card'
};