naturalSort.insensitive = true;

Vue.filter('naturalOrderBy', function (arr, sortKey, reverse) {
    if (!sortKey) {
        return arr;
    }
    var order = (reverse && reverse < 0) ? -1 : 1;

    return arr.slice().sort(naturalSort.bind(null, sortKey, order));
});

/*
 * Natural Sort algorithm for Javascript - Version 0.8.1 - Released under MIT license
 * Author: Jim Palmer (based on chunking idea from Dave Koelle)
 * https://github.com/overset/javascript-natural-sort
 *
 * Modified for vue.js 1
 */
function naturalSort (sortKey, order, a, b) {
    if (sortKey !== '$key') {
        if (Vue.util.isObject(a) && '$value' in a) a = a.$value;
        if (Vue.util.isObject(b) && '$value' in b) b = b.$value;
    }
    a = Vue.util.isObject(a) ? Vue.parsers.path.getPath(a, sortKey) : a;
    b = Vue.util.isObject(b) ? Vue.parsers.path.getPath(b, sortKey) : b;

    var re = /(^([+\-]?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?(?=\D|\s|$))|^0x[\da-fA-F]+$|\d+)/g,
        sre = /^\s+|\s+$/g,   // trim pre-post whitespace
        snre = /\s+/g,        // normalize all whitespace to single ' ' character
        dre = /(^([\w ]+,?[\w ]+)?[\w ]+,?[\w ]+\d+:\d+(:\d+)?[\w ]?|^\d{1,4}[\/\-]\d{1,4}[\/\-]\d{1,4}|^\w+, \w+ \d+, \d{4})/,
        hre = /^0x[0-9a-f]+$/i,
        ore = /^0/,
        i = function(s) {
            return (naturalSort.insensitive && ('' + s).toLowerCase() || '' + s).replace(sre, '');
        },
        // convert all to strings strip whitespace
        x = i(a),
        y = i(b),
        // chunk/tokenize
        xN = x.replace(re, '\0$1\0').replace(/\0$/,'').replace(/^\0/,'').split('\0'),
        yN = y.replace(re, '\0$1\0').replace(/\0$/,'').replace(/^\0/,'').split('\0'),
        // numeric, hex or date detection
        xD = parseInt(x.match(hre), 16) || (xN.length !== 1 && Date.parse(x)),
        yD = parseInt(y.match(hre), 16) || xD && y.match(dre) && Date.parse(y) || null,
        normChunk = function(s, l) {
            // normalize spaces; find floats not starting with '0', string or 0 if not defined (Clint Priest)
            return (!s.match(ore) || l == 1) && parseFloat(s) || s.replace(snre, ' ').replace(sre, '') || 0;
        },
        oFxNcL, oFyNcL;
    // first try and sort Hex codes or Dates
    if (yD) {
        if (xD < yD) { return -order; }
        else if (xD > yD) { return order; }
    }
    // natural sorting through split numeric strings and default strings
    for(var cLoc = 0, xNl = xN.length, yNl = yN.length, numS = Math.max(xNl, yNl); cLoc < numS; cLoc++) {
        oFxNcL = normChunk(xN[cLoc] || '', xNl);
        oFyNcL = normChunk(yN[cLoc] || '', yNl);
        // handle numeric vs string comparison - number < string - (Kyle Adams)
        if (isNaN(oFxNcL) !== isNaN(oFyNcL)) {
            return isNaN(oFxNcL) ? order : -order;
        }
        // if unicode use locale comparison
        if (/[^\x00-\x80]/.test(oFxNcL + oFyNcL) && oFxNcL.localeCompare) {
            var comp = oFxNcL.localeCompare(oFyNcL);
            var returnVal = comp / Math.abs(comp);
            return (returnVal === 0 ? 0 : (returnVal === 1 ? order : -order));
        }
        if (oFxNcL < oFyNcL) { return -order; }
        else if (oFxNcL > oFyNcL) { return order; }
    }
}