Calculate and return time ago

strings.xml

<resources>
    <string name="time_ago_prefix"></string>
    <string name="time_ago_suffix">trước</string>
    <string name="time_ago_seconds">Vừa xong</string>
    <string name="time_ago_minute">Khoảng 1 phút</string>
    <string name="time_ago_minutes">%d phút</string>
    <string name="time_ago_hour">Khoảng 1 giờ</string>
    <string name="time_ago_hours">Khoảng %d giờ</string>
    <string name="time_ago_day">một ngày</string>
    <string name="time_ago_days">%d ngày</string>
    <string name="time_ago_month">Khoảng 1 tháng</string>
    <string name="time_ago_months">%d tháng</string>
    <string name="time_ago_year">Khoảng 1 năm</string>
    <string name="time_ago_years">%d năm</string>
  </resources>

TimeAgo.java

import java.util.Date;

import android.content.res.Resources;

public class TimeAgo {
    public static String timeAgo(Date date) {
        return timeAgo(date.getTime());
    }

    public static String timeAgo(long millis) {
        long diff = new Date().getTime() - millis;

        Resources r = globalContext.getResources();

        String prefix = r.getString(R.string.time_ago_prefix);
        String suffix = r.getString(R.string.time_ago_suffix);

        double seconds = Math.abs(diff) / 1000;
        double minutes = seconds / 60;
        double hours = minutes / 60;
        double days = hours / 24;
        double years = days / 365;

        String words;

        if (seconds < 45) {
            return r.getString(R.string.time_ago_seconds);
        } else if (seconds < 90) {
            words = r.getString(R.string.time_ago_minute, 1);
        } else if (minutes < 45) {
            words = r.getString(R.string.time_ago_minutes, Math.round(minutes));
        } else if (minutes < 90) {
            words = r.getString(R.string.time_ago_hour, 1);
        } else if (hours < 24) {
            words = r.getString(R.string.time_ago_hours, Math.round(hours));
        } else if (hours < 42) {
            words = r.getString(R.string.time_ago_day, 1);
        } else if (days < 30) {
            words = r.getString(R.string.time_ago_days, Math.round(days));
        } else if (days < 45) {
            words = r.getString(R.string.time_ago_month, 1);
        } else if (days < 365) {
            words = r.getString(R.string.time_ago_months, Math.round(days / 30));
        } else if (years < 1.5) {
            words = r.getString(R.string.time_ago_year, 1);
        } else {
            words = r.getString(R.string.time_ago_years, Math.round(years));
        }

        StringBuilder sb = new StringBuilder();

        if (prefix != null && prefix.length() > 0) {
            sb.append(prefix).append(" ");
        }

        sb.append(words);

        if (suffix != null && suffix.length() > 0) {
            sb.append(" ").append(suffix);
        }

        return sb.toString().trim();
    }
}