var test = require('../util/test')(__filename);

var curry = require('../../packages/function-curry');

test('converts n-ary function to a sequence of nested unary functions', function(t) {

t.plan(13);

function addThree(x, y, z) {

return x + y + z;

}

var curryAddThree = curry(addThree);

t.equal(typeof curryAddThree(3), 'function');

t.equal(typeof curryAddThree(3, 2), 'function');

t.equal(typeof curryAddThree(3, 2, 5), 'number');

t.equal(typeof curryAddThree(3)(5)(4), 'number');

t.equal(curryAddThree(3, 2, 5), 10);

t.equal(curryAddThree(3)(5)(4), 12);

var addTwoTo2 = curry(addThree)(2);

t.equal(typeof addTwoTo2(3), 'function');

t.equal(typeof addTwoTo2(3)(6), 'number');

t.equal(typeof addTwoTo2(3, 6), 'number');

t.equal(addTwoTo2(5)(8), 15);

t.equal(addTwoTo2(13, 21), 36);

t.equal(curry(addThree)(34)(55)(89), 178);

function converter(ratio, input) {

return (input * ratio).toFixed(1);

}

var curriedConverter = curry(converter);

var milesToKm = curriedConverter(1.62);

t.equal(milesToKm(35), '56.7');

t.end();

});

test('supports arity override argument', function(t) {

t.plan(5);

function add(/* infinite number args */) {

var args = [].slice.call(arguments);

return args.reduce(function(sum, n) {

return sum + n;

}, 0);

}

var curryAdd4 = curry(add, 4);

t.equal(typeof curryAdd4(3), 'function');

t.equal(typeof curryAdd4(3)(1, 4), 'function');

t.equal(typeof curryAdd4(3)(1, 4)(2), 'number');

t.equal(curryAdd4(5)(8)(2)(7), 22);

t.equal(curryAdd4(5)(8, 4)(7), 24);

t.end();

});

test('accepts arguments exceeding arity', function(t) {

t.plan(2);

function add(/* infinite number args */) {

var args = [].slice.call(arguments);

return args.reduce(function(sum, n) {

return sum + n;

}, 0);

}

var curryAdd4 = curry(add, 4);

t.equal(typeof curryAdd4(3)(1, 4)(2, 5), 'number');

t.equal(curryAdd4(3)(1, 4)(2, 5), 15);

t.end();

});

test('does not bind supplied arguments', function(t) {

t.plan(3);

function converter(ratio, input) {

return (input * ratio).toFixed(1);

}

var milesToKm = curry(converter, 1.62);

t.equal(typeof milesToKm(35), 'function');

t.equal(milesToKm(1.62)(10), '16.2');

t.equal(milesToKm(1.62, 10), '16.2');

t.end();

});

test('still returns a function for zero-arity functions', function(t) {

t.plan(2);

function nothing() {}

t.equal(typeof curry(nothing), 'function');

t.equal(typeof curry(nothing, 1, 2, 3), 'function');

});

test('executes in the correct context', function(t) {

t.plan(2);

function converter(ratio, input) {

return (input * ratio).toFixed(this.dps);

}

var milesToKm = curry(converter)(1.62);

t.equal(milesToKm.call({dps: 0}, 35), '57');

t.equal(milesToKm.call({dps: 2}, 35), '56.70');

t.end();

});