'use strict';

Object.defineProperty(exports, "__esModule", {
    value: true
});

var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

function copyWith(obj, key, value) {
    var result = typeof key === 'number' ? [].concat(_toConsumableArray(obj)) : _extends({}, obj);
    result[key] = value;
    return result;
}

var cowValueModel = exports.cowValueModel = function cowValueModel(key) {
    var keys = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : key.split('.');

    function setField() {
        var x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
        var index = arguments[1];
        var val = arguments[2];

        if (index >= keys.length) return val;
        var key = keys[index],
            value = x[key],
            modified = setField(value, index + 1, val);
        return value === modified ? x : copyWith(x, key, modified);
    }

    var GET_SENTINEL = {};

    return function (obj) {
        var val = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : GET_SENTINEL;
        return val === GET_SENTINEL ? keys.reduce(function () {
            var x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
            var key = arguments[1];
            return x[key];
        }, obj) : setField(obj, 0, val);
    };
};