package lectio.cal;

import java.io.Serializable;
import java.util.Date;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
import org.joda.time.DateTimeConstants;
import org.joda.time.LocalDate;

/**
 * Represents a Liturgical year in the Church of Sweden tradition.<br> 
 * 
 * Note that calendar year and liturgical year doesn't align. The liturgical 
 * year starts first Sunday of Advent the previous calendar year. <br>
 * The year used in this class is the year of the Easter Sunday of this liturgical year.
 * I.e. the liturgical year 2013 starts 2012-12-02.<br>
 * 
 * Inspiration from http://www.lysator.liu.se/alma/alma.cgi 
 * 
 * http://www.svenskakyrkan.se/tcrot/kyrkoordningen/filer/KO-kap-28.pdf
 * 
 * @author marvi
 */
public class LiturgicalYear implements Serializable {

    /**
     * The year this liturgical years Easter Sunday occurs. 
     */
    private final int year;
    private LocalDate easterDay;
    private int readingCycle;
    private SortedMap<LocalDate, Day> daysOfYear = new TreeMap<LocalDate, Day>();
    private final String[] swedishCounting = new String[] {"Första", "Andra", "Tredje", "Fjärde", "Femte",
            "Sjätte", "Sjunde", "Åttonde", "Nionde", "Tionde", "Elfte", "Tolfte", "Trettonde",
            "Fjortonde", "Femtonde", "Sextonde", "Sjuttonde", "Artonde", "Nittonde", "Tjugonde",
            "Tjugoförsta", "Tjugoandra", "Tjugotredje", "Tjugofjärde", "Tjugofemte", "Tjugosjätte",
            "Tjugosjunde"};

    /**
     * 
     * @param year The year to use. 
     */
    public LiturgicalYear(int year) {
        this.year = year;
        this.readingCycle = this.getReadingCycle();
        easterDay = CalculateEaster.forYear(year);
        populateDaysOfYear();
    }

    /**
     * Default constructor. Uses current year.
     */
    public LiturgicalYear() {
        this.year = new LocalDate(new Date()).getYear();
        easterDay = CalculateEaster.forYear(year);
        populateDaysOfYear();
    }

    /**
     * @return the year
     */
    public int getYear() {
        return year;
    }

    /**
     * 
     * @return the reading cycle for this liturgical year (1-3) 
     */
    public final int getReadingCycle() {
        return getReadingCycle(year);
    }

    public final int getEasterSeries() {
        return getEasterSeries(year);
    }

    public static int getReadingCycle(int year) {
        if (year < 1986) {
            return 0;
        } else if (year < 2003) {
            return (year - 1986) % 3 + 1;
        }
        return (year - 2003) % 3 + 1;        
    }

    public static int getEasterSeries(int year) {
        if (year < 2004) {
            return 0;
        }
        return (year - 2002) % 4 + 1;
    }

    
    /**
     * Maps the holidays to actual dates for this year. 
     */
    private void populateDaysOfYear() {

        // Fixed days
        daysOfYear.put(new LocalDate(year - 1, 12, 24), new Day("Julnatten", new LocalDate(year - 1, 12, 24), readingCycle));
        daysOfYear.put(new LocalDate(year - 1, 12, 25), new Day("Juldagen", new LocalDate(year - 1, 12, 25), readingCycle));
        daysOfYear.put(new LocalDate(year - 1, 12, 26), new Day("Annandag jul", new LocalDate(year - 1, 12, 26), readingCycle));
        daysOfYear.put(new LocalDate(year - 1, 12, 31), new Day("Nyårsafton", new LocalDate(year - 1, 12, 31), readingCycle));
        daysOfYear.put(new LocalDate(year, 1, 1), new Day("Nyårsdagen", new LocalDate(year, 1, 1), readingCycle));
        daysOfYear.put(new LocalDate(year, 1, 5), new Day("Trettondagsafton", new LocalDate(year, 1, 5), readingCycle));
        daysOfYear.put(new LocalDate(year, 1, 6), new Day("Trettondedag jul", new LocalDate(year, 1, 6), readingCycle));

        // Söndagen efter jul infaller inte varje år.
        LocalDate sej = nextWeekdayOfType(DateTimeConstants.SUNDAY, new LocalDate((year - 1), 12, 26));
        if (sej.isBefore(new LocalDate(year, 1, 1))) {
            daysOfYear.put(sej, new Day("Söndagen efter jul", sej, readingCycle));
        }

        // "Söndagen efter nyår" infaller inte varje år. 
        if (sundayAfterNewYear() != null) {
            daysOfYear.put(sundayAfterNewYear(), new Day("Söndagen efter nyår", sundayAfterNewYear(), readingCycle));
        }

        // Kyndelsmässodagen (flyttas tillbaka en vecka om den infaller på fastlagssöndagen
        LocalDate kynd = nextWeekdayOfType(DateTimeConstants.SUNDAY, new LocalDate(year, 2, 1));
        if (kynd.equals(easterDay.minusDays(49))) {
            kynd = kynd.minusDays(7);
        }
        daysOfYear.put(kynd, new Day("Kyndelsmässodagen", kynd, readingCycle));

        // Söndagar efter trettondedagen
        int add = 0;
        int i = 0;
        while (i < 8) {
            LocalDate d = firstAfterEpifania().plusDays(add);
            if (!d.isEqual(kynd) && d.isBefore(easterDay.minusDays(63))) {
                String prefix = swedishCounting[i];
                daysOfYear.put(d, new Day(prefix + " söndagen efter trettondedagen", d, readingCycle));
            } else if (d.isEqual(easterDay.minusDays(63))
                    || d.isAfter(easterDay.minusDays(63))) {
                i = 8;
            }
            add = add + 7;
            i++;
        }

        // Jungfru Marie bebådelsedag
        LocalDate jmb = nextWeekdayOfType(DateTimeConstants.SUNDAY, new LocalDate(year, 3, 21));
        if (jmb.isAfter(easterDay.minusDays(8))) {
            jmb = easterDay.minusDays(14);
        }
        daysOfYear.put(jmb, new Day("Jungfru Marie bebådelsedag", jmb, readingCycle));
        //System.out.println(daysOfYear.get(jmb) + " " + easterDay.minusDays(42));
        if (!kynd.isEqual(easterDay.minusDays(63))) {
            daysOfYear.put(easterDay.minusDays(63), new Day("Septuagesima", easterDay.minusDays(63), readingCycle));
        }
        if (!kynd.isEqual(easterDay.minusDays(56))) {
            daysOfYear.put(easterDay.minusDays(56), new Day("Sexagesima", easterDay.minusDays(56), readingCycle));
        }
        daysOfYear.put(easterDay.minusDays(49), new Day("Fastlagssöndagen", easterDay.minusDays(49), readingCycle));
        daysOfYear.put(easterDay.minusDays(46), new Day("Askonsdagen", easterDay.minusDays(46), readingCycle));
        if (!jmb.isEqual(easterDay.minusDays(42))) {
            daysOfYear.put(easterDay.minusDays(42), new Day("Första söndagen i fastan", easterDay.minusDays(42), readingCycle));
        }
        if (!jmb.isEqual(easterDay.minusDays(35))) {
            daysOfYear.put(easterDay.minusDays(35), new Day("Andra söndagen i fastan", easterDay.minusDays(35), readingCycle));
        }
        if (!jmb.isEqual(easterDay.minusDays(28))) {
            daysOfYear.put(easterDay.minusDays(28), new Day("Tredje söndagen i fastan", easterDay.minusDays(28), readingCycle));
        }
        if (!jmb.isEqual(easterDay.minusDays(21))) {
            daysOfYear.put(easterDay.minusDays(21), new Day("Midfastosöndagen", easterDay.minusDays(21), readingCycle));
        }
        if (!jmb.isEqual(easterDay.minusDays(14))) {
            daysOfYear.put(easterDay.minusDays(14), new Day("Femte söndagen i fastan", easterDay.minusDays(14), readingCycle));
        }
        // Utgår från påsken
        daysOfYear.put(easterDay, new Day("Påskdagen", easterDay, readingCycle));
        daysOfYear.put(easterDay.minusDays(1), new Day("Påsknatten", easterDay.minusDays(1), readingCycle));
        daysOfYear.put(easterDay.minusDays(2), new Day("Långfredagen", easterDay.minusDays(2), readingCycle));
        daysOfYear.put(easterDay.minusDays(3), new Day("Skärtorsdagen", easterDay.minusDays(3), readingCycle));
        daysOfYear.put(easterDay.minusDays(4), new Day("Onsdag i Stilla veckan", easterDay.minusDays(4), readingCycle));
        daysOfYear.put(easterDay.minusDays(5), new Day("Tisdag i Stilla veckan", easterDay.minusDays(5), readingCycle));
        daysOfYear.put(easterDay.minusDays(6), new Day("Måndag i Stilla veckan", easterDay.minusDays(6), readingCycle));
        daysOfYear.put(easterDay.minusDays(7), new Day("Palmsöndagen", easterDay.minusDays(7), readingCycle));
        daysOfYear.put(easterDay.plusDays(1), new Day("Annandag påsk", easterDay.plusDays(1), readingCycle));
        daysOfYear.put(easterDay.plusDays(7), new Day("Andra söndagen i påsktiden", easterDay.plusDays(7), readingCycle));
        daysOfYear.put(easterDay.plusDays(14), new Day("Tredje söndagen i påsktiden", easterDay.plusDays(14), readingCycle));
        daysOfYear.put(easterDay.plusDays(21), new Day("Fjärde söndagen i påsktiden", easterDay.plusDays(21), readingCycle));
        daysOfYear.put(easterDay.plusDays(28), new Day("Femte söndagen i påsktiden", easterDay.plusDays(28), readingCycle));
        daysOfYear.put(easterDay.plusDays(35), new Day("Bönsöndagen", easterDay.plusDays(35), readingCycle));
        daysOfYear.put(easterDay.plusDays(39), new Day("Kristi himmelsfärds dag", easterDay.plusDays(39), readingCycle));
        daysOfYear.put(easterDay.plusDays(42), new Day("Söndagen före pingst", easterDay.plusDays(42), readingCycle));
        daysOfYear.put(easterDay.plusDays(49), new Day("Pingstdagen", easterDay.plusDays(49), readingCycle));
        daysOfYear.put(easterDay.plusDays(50), new Day("Annandag pingst", easterDay.plusDays(50), readingCycle));
        daysOfYear.put(easterDay.plusDays(56), new Day("Heliga trefaldighets dag", easterDay.plusDays(56), readingCycle));

        // Midsommardagen
        LocalDate msd = nextWeekdayOfType(DateTimeConstants.SATURDAY, new LocalDate(year, 6, 19));
        daysOfYear.put(msd, new Day("Midsommardagen", msd, readingCycle));


        // Alla helons dag (behövs för att lägga ut trefaldighetstiden)
        LocalDate ahd = nextWeekdayOfType(DateTimeConstants.SATURDAY, new LocalDate(year, 10, 30));
        daysOfYear.put(ahd, new Day("Alla helgons dag", ahd, readingCycle));
        daysOfYear.put(ahd.plusDays(1), new Day("Söndagen efter alla helgons dag", ahd.plusDays(1), readingCycle));

        // Advent och kyrkoårets slut
        LocalDate firstAdv = nextWeekdayOfType(DateTimeConstants.SUNDAY, new LocalDate((year - 1), 11, 26));
        daysOfYear.put(firstAdv, new Day("Första söndagen i advent", firstAdv, readingCycle));
        daysOfYear.put(firstAdv.plusDays(7), new Day("Andra söndagen i advent", firstAdv.plusDays(7), readingCycle));
        daysOfYear.put(firstAdv.plusDays(14), new Day("Tredje söndagen i advent", firstAdv.plusDays(14), readingCycle));
        daysOfYear.put(firstAdv.plusDays(21), new Day("Fjärde söndagen i advent", firstAdv.plusDays(21), readingCycle));

        // Kalenderårsadvent (för att räkna ut Domsöndag
        LocalDate calFirstAdv = nextWeekdayOfType(DateTimeConstants.SUNDAY, new LocalDate((year), 11, 26));
        daysOfYear.put(calFirstAdv.minusDays(7), new Day("Domsöndagen", calFirstAdv.minusDays(7), readingCycle));
        daysOfYear.put(calFirstAdv.minusDays(14), new Day("Söndagen före domsöndagen", calFirstAdv.minusDays(7), readingCycle));

        // Trefaldighetssöndagarna
        // Söndagar efter trettondedagen
        LocalDate firstAfterTre = easterDay.plusDays(63);
        add = 0;
        i = 0;
        while (i < 27) {
            LocalDate setre = firstAfterTre.plusDays(add);
            add = add + 7;
            if (setre.isEqual(ahd.plusDays(1))) {
                i++;
                continue;
            }
            if (setre.isAfter(calFirstAdv.minusDays(15))) {
                break;
            }
            String etreName = swedishCounting[i];
            switch (i) {
                case 4:
                    daysOfYear.put(setre, new Day("Apostladagen", setre, readingCycle));
                    break;
                case 6:
                    daysOfYear.put(setre, new Day("Kristi förklarings dag", setre, readingCycle));
                    break;
                default:
                    daysOfYear.put(setre, new Day(etreName + " söndagen efter trefaldighet", setre, readingCycle));
                    break;
            }
            i++;
        }

        // Johannes döparens dag
        daysOfYear.put(msd.plusDays(1), new Day("Den helige Johannes Döparens dag", msd.plusDays(1), readingCycle));

        // Den helige Mikaels dag
        LocalDate hmd = nextWeekdayOfType(DateTimeConstants.SUNDAY, new LocalDate(year, 9, 28));
        daysOfYear.put(hmd, new Day("Den helige Mikaels dag", hmd, readingCycle));

        // Tacksägelsedagen
        LocalDate tsd = nextWeekdayOfType(DateTimeConstants.SUNDAY, new LocalDate(year, 9, 30));
        tsd = nextWeekdayOfType(DateTimeConstants.SUNDAY, tsd);
        daysOfYear.put(tsd, new Day("Tacksägelsedagen", tsd, readingCycle));


    }

    private LocalDate sundayAfterNewYear() {
        LocalDate candidate = nextWeekdayOfType(DateTimeConstants.SUNDAY, new LocalDate(year, 1, 1));
        if (candidate.getDayOfMonth() < 6) {
            return candidate;
        }
        return null;
    }

    private LocalDate firstAfterEpifania() {
        LocalDate ep = new LocalDate(year, 1, 6);
        return nextWeekdayOfType(DateTimeConstants.SUNDAY, ep);
    }

    /**
     * 
     * @param wd The day of week
     * @param date The date to start from
     * @return The next date with this weekday
     */
    protected static LocalDate nextWeekdayOfType(int wd, LocalDate date) {
        if (date.getDayOfWeek() < wd) {
            date = date.withDayOfWeek(wd);
        } else {
            date = date.plusWeeks(1).withDayOfWeek(wd);
        }
        return date;
    }

    /**
     * @return a map with a date as key and the Day as value.
     */
    public Map<LocalDate, Day> getDaysOfYear() {
        return daysOfYear;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("LiturgicalYear{ year=");
        sb.append(year);
        sb.append(" ");
        Set<LocalDate> days = daysOfYear.keySet();
        for (LocalDate ld : days) {
            sb.append(daysOfYear.get(ld).toString());
            sb.append(" \n ");
        }
        sb.append(" }");
        return sb.toString();
    }

}