# -*- coding: utf-8 -*-
#
# Gramps - a GTK+/GNOME based genealogy program
#
# Copyright (C) 2000-2007  Donald N. Allingham
# Copyright (C) 2008-2009  Brian G. Matherly
# Copyright (C) 2009       Rob G. Healey <robhealey1@gmail.com>
# Copyright (C) 2014       Vlada Perić <vlada.peric@gmail.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

#------------------------------------------------------------------------
#
# python modules
#
#------------------------------------------------------------------------
from xml.parsers import expat
import datetime
import math
import os

#------------------------------------------------------------------------
#
# Gramps modules
#
#------------------------------------------------------------------------
from gramps.gen.const import GRAMPS_LOCALE as glocale
_ = glocale.translation.gettext
from gramps.gen.const import PLUGINS_DIR, USER_PLUGINS, DATA_DIR
from gramps.gen.lib.gcalendar import (gregorian_ymd, hebrew_sdn)

#------------------------------------------------------------------------
#
# Support functions
#
#------------------------------------------------------------------------
def g2iso(dow):
    """ Converst Gramps day of week to ISO day of week """
    # Gramps: SUN = 1
    # ISO: MON = 1
    return (dow + 5) % 7 + 1

def easter(year):
    """
    Computes the year/month/day of easter. Based on work by
    J.-M. Oudin (1940) and is reprinted in the "Explanatory Supplement
    to the Astronomical Almanac", ed. P. K.  Seidelmann (1992).  Note:
    Ash Wednesday is 46 days before Easter Sunday.
    """
    c = year // 100
    n = year - 19 * (year // 19)
    k = (c - 17) // 25
    i = c - c // 4 - (c - k) // 3 + 19 * n + 15
    i = i - 30 * (i // 30)
    i = i - (i // 28) * (1 - (i // 28) * (29 // (i + 1)) * ((21 - n) // 11) )
    j = year + year // 4 + i + 2 - c + c // 4
    j = j - 7 * (j // 7)
    l = i - j
    month = 3 + (l + 40) // 44
    day = l + 28 - 31 * (month // 4)
    return "%d/%d/%d" % (year, month, day)

def julian_easter(year):
    """
    Computes the year/month/day of Eastern Orthodox Easter, given in the
    Gregorian calendar. Implements the Jean Meeus algorithm. Valid: 1900-2099.
    """
    a = year % 4
    b = year % 7
    c = year % 19
    d = (19*c + 15) % 30
    e = (2*a + 4*b - d + 34) % 7
    month = int(math.floor((d + e + 114) / 31))
    day = ((d + e + 114) % 31) + 1

    # produced date was in the Julian calendar, add 13 days to it
    day = day + 13

    if month == 3 and day > 31:
        day = day - 31
        month = 4
    elif month == 4 and day > 30:
        day = day - 30
        month = 5

    return "%d/%d/%d" % (year, month, day)

def passover(year):
    """
    Returns the date of Passover in a given Gregorian year.
    """
    heb_year = year + 3760
    heb = hebrew_sdn(heb_year, 8, 15) #Passover, 15 Nissan

    return "%d/%d/%d" % gregorian_ymd(heb)

def hanuka(year):
    """
    Returns the date of first day of Hanuka in a given Gregorian year.
    We can't use passover as an offset, because the year length changes.
    The hebrew year have 6 possible lengths.
    """
    heb_year = year + 3761  #Not 3760, because Hanuka is in Nov/Dec of the previous year
    heb = hebrew_sdn(heb_year, 3, 25) #Hanuka, 25 Kislev

    return "%d/%d/%d" % gregorian_ymd(heb)

def dst(year, area="us"):
    """
    Return Daylight Saving Time start/stop in a given area ("us", "eu").
    US calculation valid 1976-2099; EU 1996-2099
    """
    if area == "us":
        if year > 2006:
            start = "%d/%d/%d" % (year, 3, 14 - (math.floor(1 + year * 5 / 4) % 7)) # March
            stop = "%d/%d/%d" % (year, 11, 7 - (math.floor(1 + year * 5 / 4) % 7)) # November
        else:
            start = "%d/%d/%d" % (year, 4, (2 + 6 * year - math.floor(year / 4)) % 7 + 1) # April
            stop =  "%d/%d/%d" % (year, 10, (31 - (math.floor(year * 5 / 4) + 1) % 7)) # October
    elif area == "eu":
        start = "%d/%d/%d" % (year, 3, (31 - (math.floor(year * 5 / 4) + 4) % 7)) # March
        stop =  "%d/%d/%d" % (year, 10, (31 - (math.floor(year * 5 / 4) + 1) % 7)) # Oct
    return (start, stop)

def dow(y, m, d):
    """ Return the ISO day of week for the given year, month and day. """
    return datetime.date(y, m, d).isoweekday()

def cmp(a, b):
    """
    Replacement for older Python's cmp.
    """
    return (a > b) - (a < b)

#------------------------------------------------------------------------
#
# HolidayTable
#
#------------------------------------------------------------------------
class HolidayTable:
    """
    HolidayTable is a class which provides holidays for various
    countries and years.
    """
    __holiday_files = []
    __countries = []

    def __init__(self):
        """
        Find the holiday files and load the countries if it has not already
        been done.
        """
        if( not HolidayTable.__holiday_files ):
            self.__find_holiday_files()

        if( not HolidayTable.__countries ):
            self.__build_country_list()

        # Initialize the holiday table to be empty
        self.__holidays = {}
        self.__init_table()

    def __find_holiday_files(self):
        """
        Looks in multiple places for holidays.xml files
        It will search for the file in user's plugin directories first,
        then it will search in program's plugins directories.
        """

        holiday_file = 'holidays.xml'

        # Look for holiday files in the user plugins directory and all
        # subdirectories.
        for (dirpath, dirnames, filenames) in os.walk(USER_PLUGINS):
            holiday_full_path = os.path.join(dirpath, holiday_file)
            if os.path.exists(holiday_full_path):
                HolidayTable.__holiday_files.append(holiday_full_path)

        # Look for holiday files in the installation data directory and all
        # subdirectories.
        for (dirpath, dirnames, filenames) in os.walk(DATA_DIR):
            holiday_full_path = os.path.join(dirpath, holiday_file)
            if os.path.exists(holiday_full_path):
                HolidayTable.__holiday_files.append(holiday_full_path)

    def __build_country_list(self):
        """ Generate the list of countries that have holiday information. """
        for holiday_file_path in HolidayTable.__holiday_files:
            parser = _Xml2Obj()
            root_element = parser.parse(holiday_file_path)
            for country_element in root_element.get_children():
                if country_element.get_name() == "country":
                    country_name = country_element.get_attribute("name")
                    if country_name not in HolidayTable.__countries:
                        HolidayTable.__countries.append(_(country_name))

    def __init_table(self):
        """ Initialize the holiday table structure. """
        for month in range(1, 13):
            self.__holidays[month] = {}
            for day in range(1, 32):
                self.__holidays[month][day] = []

    def get_countries(self):
        """
        Get all the country names that holidays are available for.

        @return: nothing
        """
        return HolidayTable.__countries

    def load_holidays(self, year, country):
        """
        Load the holiday table for the specified year and country.
        This must be called before get_holidays().

        @param year: The year for which the holidays should be loaded.
            Example: 2010
        @type year: int
        @param country: The country for which the holidays should be loaded.
            Example: "United States"
        @type country: str
        @return: nothing
        """
        self.__init_table()
        for holiday_file_path in HolidayTable.__holiday_files:
            parser = _Xml2Obj()
            element = parser.parse(holiday_file_path)
            calendar = _Holidays(element, country)
            date = datetime.date(year, 1, 1)
            while date.year == year:
                holidays = calendar.check_date(date)
                for text in holidays:
                    self.__holidays[date.month][date.day].append(_(text))
                date = date.fromordinal(date.toordinal() + 1)

    def get_holidays(self, month, day):
        """
        Get the holidays for the given day of the year.

        @param month: The month for the requested holidays.
            Example: 1
        @type month: int
        @param month: The day for the requested holidays.
            Example: 1
        @type month: int
        @return: An array of strings with holiday names.
        @return type: [str]
        """
        return self.__holidays[month][day]

#------------------------------------------------------------------------
#
# _Element
#
#------------------------------------------------------------------------
class _Element:
    """ A parsed XML element """
    def __init__(self, name, attributes):
        'Element constructor'
        # The element's tag name
        self.__name = name
        # The element's attribute dictionary
        self.__attributes = attributes
        # The element's child element list (sequence)
        self.__children = []

    def add_child(self, element):
        'Add a reference to a child element'
        self.__children.append(element)

    def get_attribute(self, key):
        'Get an attribute value'
        return self.__attributes.get(key)

    def get_attributes(self):
        'Get all the attributes'
        return self.__attributes

    def get_name(self):
        """ Get the name of this element. """
        return self.__name

    def get_children(self):
        """ Get the children elements for this element. """
        return self.__children

#------------------------------------------------------------------------
#
# _Xml2Obj
#
#------------------------------------------------------------------------
class _Xml2Obj:
    """ XML to Object """
    def __init__(self):
        self.root = None
        self.nodeStack = []

    def start_element(self, name, attributes):
        'SAX start element even handler'
        # Instantiate an Element object
        element = _Element(name, attributes)
        # Push element onto the stack and make it a child of parent
        if len(self.nodeStack) > 0:
            parent = self.nodeStack[-1]
            parent.add_child(element)
        else:
            self.root = element
        self.nodeStack.append(element)

    def end_element(self, name):
        'SAX end element event handler'
        self.nodeStack = self.nodeStack[:-1]

    def parse(self, filename):
        'Create a SAX parser and parse filename '
        parser = expat.ParserCreate()
        # SAX event handlers
        parser.StartElementHandler = self.start_element
        parser.EndElementHandler = self.end_element
        # Parse the XML File
        with open(filename, 'rb') as xml_file:
            parser.ParseFile(xml_file)
        return self.root

#------------------------------------------------------------------------
#
# _Holidays
#
#------------------------------------------------------------------------
class _Holidays:
    """ Class used to read XML holidays to add to calendar. """
    MONTHS = ['jan', 'feb', 'mar', 'apr', 'may', 'jun',
              'jul', 'aug', 'sep', 'oct', 'nov', 'dec']
    DAYS = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun']
    WORKDAY = list(range(5)) # indexes into above
    WEEKEND = (5, 6) # indexes into above
    def __init__(self, elements, country="US"):
        self.debug = 0
        self.elements = elements
        self.country = country
        self.dates = []
        self.initialize()

    def set_country(self, country):
        """ Set the contry of holidays to read """
        self.country = country
        self.dates = []
        self.initialize()

    def initialize(self):
        """ Parse the holiday date XML items """
        for country_set in self.elements.get_children():
            if country_set.get_name() == "country" and \
               _(country_set.get_attribute("name")) == self.country:
                for date in country_set.get_children():
                    if date.get_name() == "date":
                        data = {"value" : "",
                                "name" : "",
                                "offset": "",
                                "type": "",
                                "if": "",
                                } # defaults
                        for attr in date.get_attributes():
                            data[attr] = date.get_attribute(attr)
                        self.dates.append(data)

    def get_daynames(self, year, month, dayname):
        """ Get the items for a particular year/month and day of week """
        if self.debug:
            print("%s's in %d %d..." % (dayname, month, year))

        retval = [0]
        day_of_week = self.DAYS.index(dayname)
        for day in range(1, 32):
            try:
                date = datetime.date(year, month, day)
            except ValueError:
                continue
            if date.weekday() == day_of_week:
                retval.append(day)

        if self.debug:
            print("day_of_week=", day_of_week, "days=", retval)

        return retval

    def check_date(self, date):
        """ Return items that match rules """
        retval = []
        for rule in self.dates:

            if self.debug:
                print("Checking ", rule["name"], "...")

            offset = 0
            if rule["offset"] != "":
                if rule["offset"].isdigit():
                    offset = int(rule["offset"])
                elif rule["offset"][0] in ["-", "+"] and \
                     rule["offset"][1:].isdigit():
                    offset = int(rule["offset"])
                else:
                    # must be a dayname or "workday"
                    offset = rule["offset"]

            if rule["value"].startswith('>'):
                # eval exp -> year/num[/day[/month]]
                y, m, d = date.year, date.month, date.day
                rule["value"] = eval(rule["value"][1:])

            if self.debug:
                print("rule['value']:", rule["value"])
            if rule["value"].count("/") == 3: # year/num/day/month, "3rd wednesday in april"
                y, num, dayname, mon = rule["value"].split("/")
                if y == "*":
                    y = date.year
                else:
                    y = int(y)
                if mon.isdigit():
                    m = int(mon)
                elif mon == "*":
                    m = date.month
                elif mon in self.MONTHS:
                    m = self.MONTHS.index(mon) + 1
                dates_of_dayname = self.get_daynames(y, m, dayname)

                if self.debug:
                    print("num =", num)

                d = dates_of_dayname[int(num)]

            elif rule["value"].count("/") == 2: # year/month/day
                y, m, d = rule["value"].split("/")
                if y == "*":
                    y = date.year
                else:
                    y = int(y)
                if m == "*":
                    m = date.month
                elif m in self.MONTHS:
                    m = self.MONTHS.index(m) + 1
                else:
                    m = int(m)
                if d == "*":
                    d = date.day
                else:
                    d = int(d)
            ndate = datetime.date(y, m, d)

            if self.debug:
                print(ndate, offset, type(offset))

            if isinstance(offset, int):
                if offset != 0:
                    ndate = ndate.fromordinal(ndate.toordinal() + offset)
            elif isinstance(offset, str):
                direction = 1
                if offset[0] == "-":
                    direction = -1
                    offset = offset[1:]
                elif offset[0] == "+":
                    direction = 1
                    offset = offset[1:]

                if offset == "workday":
                    # next workday you come to, including this one
                    day_of_week = self.WORKDAY
                    ordinal = ndate.toordinal()
                    while ndate.fromordinal(ordinal).weekday() not in day_of_week:
                        ordinal += direction
                    ndate = ndate.fromordinal(ordinal)
                elif offset == "weekend":
                    # next weekend you come to, including this one
                    day_of_week = self.WEEKEND
                    ordinal = ndate.toordinal()
                    while ndate.fromordinal(ordinal).weekday() not in day_of_week:
                        ordinal += direction
                    ndate = ndate.fromordinal(ordinal)
                elif offset in self.DAYS:
                    # next tuesday you come to, including this one
                    day_of_week = self.DAYS.index(offset)
                    ordinal = ndate.toordinal()
                    while ndate.fromordinal(ordinal).weekday() != day_of_week:
                        ordinal += direction
                    ndate = ndate.fromordinal(ordinal)

            if self.debug:
                print("ndate:", ndate, "date:", date)

            if ndate == date:
                if rule["if"] != "":
                    if not eval(rule["if"]):
                        continue
                retval.append(rule["name"])

        return retval
