Get ‘time ago’ from epoch timestamp

For converting an epoch timestamp to show in the format ‘2 min ago’, ‘5 days ago’, etc.

private static final int SECOND_MILLIS = 1000;
private static final int MINUTE_MILLIS = 60 * SECOND_MILLIS;
private static final int HOUR_MILLIS = 60 * MINUTE_MILLIS;
private static final int DAY_MILLIS = 24 * HOUR_MILLIS;

public static String getTimeAgo(long time, Context ctx) {
    if (time < 1000000000000L) {
        // if timestamp given in seconds, convert to millis
        time *= 1000;
    }

    long now = System.currentTimeMillis();
    if (time > now || time <= 0) {
        return null;
    }

    final long diff = now - time;
    if (diff < MINUTE_MILLIS) {
        return "just now";
    } else if (diff < 2 * MINUTE_MILLIS) {
        return "a minute ago";
    } else if (diff < 50 * MINUTE_MILLIS) {
        return diff / MINUTE_MILLIS + " minutes ago";
    } else if (diff < 90 * MINUTE_MILLIS) {
        return "an hour ago";
    } else if (diff < 24 * HOUR_MILLIS) {
        return diff / HOUR_MILLIS + " hours ago";
    } else if (diff < 48 * HOUR_MILLIS) {
        return "yesterday";
    } else {
        return diff / DAY_MILLIS + " days ago";
    }
}

For short format, like ‘1m’, ‘2d’.

public static String getShortTimeAgo(long time, Context ctx) {
    if (time < 1000000000000L) {
        // if timestamp given in seconds, convert to millis
        time *= 1000;
    }

    long now = System.currentTimeMillis();
    if (time > now || time <= 0) {
        return null;
    }

    // TODO: localize
    final long diff = now - time;
    if (diff < MINUTE_MILLIS) {
        return "now";
    } else if (diff < 2 * MINUTE_MILLIS) {
        return "1m";
    } else if (diff < 50 * MINUTE_MILLIS) {
        return diff / MINUTE_MILLIS + "m";
    } else if (diff < 90 * MINUTE_MILLIS) {
        return "1h";
    } else if (diff < 24 * HOUR_MILLIS) {
        return diff / HOUR_MILLIS + "h";
    } else if (diff < 48 * HOUR_MILLIS) {
        return "1d";
    } else {
        return diff / DAY_MILLIS + "d";
    }
}

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