1import absFloor from '../utils/abs-floor';
2var abs = Math.abs;
3
4function sign(x) {
5    return (x > 0) - (x < 0) || +x;
6}
7
8export function toISOString() {
9    // for ISO strings we do not use the normal bubbling rules:
10    //  * milliseconds bubble up until they become hours
11    //  * days do not bubble at all
12    //  * months bubble up until they become years
13    // This is because there is no context-free conversion between hours and days
14    // (think of clock changes)
15    // and also not between days and months (28-31 days per month)
16    if (!this.isValid()) {
17        return this.localeData().invalidDate();
18    }
19
20    var seconds = abs(this._milliseconds) / 1000,
21        days = abs(this._days),
22        months = abs(this._months),
23        minutes,
24        hours,
25        years,
26        s,
27        total = this.asSeconds(),
28        totalSign,
29        ymSign,
30        daysSign,
31        hmsSign;
32
33    if (!total) {
34        // this is the same as C#'s (Noda) and python (isodate)...
35        // but not other JS (goog.date)
36        return 'P0D';
37    }
38
39    // 3600 seconds -> 60 minutes -> 1 hour
40    minutes = absFloor(seconds / 60);
41    hours = absFloor(minutes / 60);
42    seconds %= 60;
43    minutes %= 60;
44
45    // 12 months -> 1 year
46    years = absFloor(months / 12);
47    months %= 12;
48
49    // inspired by https://github.com/dordille/moment-isoduration/blob/master/moment.isoduration.js
50    s = seconds ? seconds.toFixed(3).replace(/\.?0+$/, '') : '';
51
52    totalSign = total < 0 ? '-' : '';
53    ymSign = sign(this._months) !== sign(total) ? '-' : '';
54    daysSign = sign(this._days) !== sign(total) ? '-' : '';
55    hmsSign = sign(this._milliseconds) !== sign(total) ? '-' : '';
56
57    return (
58        totalSign +
59        'P' +
60        (years ? ymSign + years + 'Y' : '') +
61        (months ? ymSign + months + 'M' : '') +
62        (days ? daysSign + days + 'D' : '') +
63        (hours || minutes || seconds ? 'T' : '') +
64        (hours ? hmsSign + hours + 'H' : '') +
65        (minutes ? hmsSign + minutes + 'M' : '') +
66        (seconds ? hmsSign + s + 'S' : '')
67    );
68}