var _curry2 = require('./internal/_curry2');
var _reduce = require('./internal/_reduce');
var ap = require('./ap');
var curryN = require('./curryN');
var map = require('./map');


/**
 * "lifts" a function to be the specified arity, so that it may "map over" that
 * many lists, Functions or other objects that satisfy the [FantasyLand Apply spec](https://github.com/fantasyland/fantasy-land#apply).
 *
 * @func
 * @memberOf R
 * @since v0.7.0
 * @category Function
 * @sig Number -> (*... -> *) -> ([*]... -> [*])
 * @param {Function} fn The function to lift into higher context
 * @return {Function} The lifted function.
 * @see R.lift, R.ap
 * @example
 *
 *      var madd3 = R.liftN(3, (...args) => R.sum(args));
 *      madd3([1,2,3], [1,2,3], [1]); //=> [3, 4, 5, 4, 5, 6, 5, 6, 7]
 */
module.exports = _curry2(function liftN(arity, fn) {
  var lifted = curryN(arity, fn);
  return curryN(arity, function() {
    return _reduce(ap, map(lifted, arguments[0]), Array.prototype.slice.call(arguments, 1));
  });
});