Day.java

package com.tfltravelalerts.model;

import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import android.content.Context;

import com.google.common.base.Joiner;
import com.tfltravelalerts.R;
import com.tfltravelalerts.TflApplication;

public enum Day {
    MONDAY(Calendar.MONDAY, R.string.day_full_monday, R.string.day_short_monday,
            R.string.day_super_short_monday),

    TUESDAY(Calendar.TUESDAY, R.string.day_full_tuesday, R.string.day_short_tuesday,
            R.string.day_super_short_tuesday),

    WEDNESDAY(Calendar.WEDNESDAY, R.string.day_full_wednesday, R.string.day_short_wednesday,
            R.string.day_super_short_wednesday),

    THURSDAY(Calendar.THURSDAY, R.string.day_full_thursday, R.string.day_short_thursday,
            R.string.day_super_short_thursday),

    FRIDAY(Calendar.FRIDAY, R.string.day_full_friday, R.string.day_short_friday,
            R.string.day_super_short_friday),

    SATURDAY(Calendar.SATURDAY, R.string.day_full_saturday, R.string.day_short_saturday,
            R.string.day_super_short_saturday),

    SUNDAY(Calendar.SUNDAY, R.string.day_full_sunday, R.string.day_short_sunday,
            R.string.day_super_short_sunday);

    private int mNormalNameResId;
    private int mShortNameResId;
    private int mSuperShortNameResId;
    private int mCalendarDay;

    private Day(int calendarDay, int normalNameResId, int shortNameResId, int superShortNameResId) {
        mCalendarDay = calendarDay;
        mNormalNameResId = normalNameResId;
        mShortNameResId = shortNameResId;
        mSuperShortNameResId = superShortNameResId;
    }

    public int getNormalNameResId() {
        return mNormalNameResId;
    }

    public int getShortNameResId() {
        return mShortNameResId;
    }

    public int getSuperShortNameResId() {
        return mSuperShortNameResId;
    }

    public int getCalendarDay() {
        return mCalendarDay;
    }
    
    public static Day[] weekdays() {
        return new Day[] {
                MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY
        };
    }

    public static Day[] weekends() {
        return new Day[] {
                SATURDAY, SUNDAY
        };
    }

    public static Day[] allDays() {
        return values();
    }

    @Override
    public String toString() {
        Context context = TflApplication.getLastInstance();
        return context.getString(getShortNameResId());
    }

    public static String buildShortString(Collection<Day> days) {
        List<Day> sortedDays = new ArrayList<Day>(days);
        Collections.sort(sortedDays);
        return Joiner.on(", ").join(sortedDays);
    }

    /**
     * Calculates the minimum number of days in the week between this and
     * another. A negative number means that the other day is reached quicker if
     * going backwards.
     * 
     * @param another
     * @return
     */
    public int daysBetween(Day another) {
        if (this.ordinal() > another.ordinal()) {
            // do the calculation when this is before another
            return -another.daysBetween(this);
        }
        int delta = another.ordinal() - this.ordinal();
        int complement = Day.values().length - delta;
        return Math.abs(complement) < Math.abs(delta) ? -complement : delta;
    }
}