function Triangle(a,b,c) {

'use strict';

this.sides = [ a, b, c ];

this.kind = function() {

var name = "scalene";

if (this.isIllegal()) {

name = "illegal";

} else if (this.isEquilateral()) {

name = "equilateral";

} else if (this.isIsosceles()) {

name = "isosceles";

}

return name;

};

this.isIllegal = function() {

return this.violatesInequality() || this.hasImpossibleSides();

};

this.violatesInequality = function() {

var a = this.sides[0], b = this.sides[1], c = this.sides[2];

return (a + b <= c) || (a + c <= b) || (b + c <= a);

};

this.hasImpossibleSides = function() {

return this.sides[0] <= 0 || this.sides[1] <= 0 || this.sides[2] <= 0;

};

this.isEquilateral = function() {

return this.uniqueSides().length === 1;

};

this.isIsosceles = function() {

return this.uniqueSides().length === 2;

};

this.uniqueSides = function() {

var sides = this.sides;

var uniques = {};

for (var i = 0; i < sides.length; i++) {

var currentSide = sides[i];

uniques[currentSide] = true;

}

var uniqueSides = [];

for (var uniqueSide in uniques) {

uniqueSides.push(uniqueSide);

}

return uniqueSides;

};

}

module.exports = Triangle;