from sys import platform
import calendar
import tkinter as tk
from tkinter import ttk
from tkinter.font import Font
from babel import default_locale
from babel.dates import format_date, parse_date, get_day_names, get_month_names, get_date_format
import re

MAPS = {'winnative': {'focusfill': [('readonly', 'focus', 'SystemHighlight')],
                      'foreground': [('disabled', 'SystemGrayText'),
                                     ('readonly', 'focus', 'SystemHighlightText')],
                      'selectforeground': [('!focus', 'SystemWindowText')],
                      'fieldbackground': [('readonly', 'SystemButtonFace'),
                                          ('disabled', 'SystemButtonFace')],
                      'selectbackground': [('!focus', 'SystemWindow')]},
        'clam': {'foreground': [('readonly', 'focus', '#ffffff')],
                 'fieldbackground': [('readonly', 'focus', '#4a6984'), ('readonly', '#dcdad5')],
                 'background': [('active', '#eeebe7'), ('pressed', '#eeebe7')],
                 'arrowcolor': [('disabled', '#999999')]},
        'alt': {'fieldbackground': [('readonly', '#d9d9d9'),
                                    ('disabled', '#d9d9d9')],
                'arrowcolor': [('disabled', '#a3a3a3')]},
        'default': {'fieldbackground': [('readonly', '#d9d9d9'), ('disabled', '#d9d9d9')],
                    'arrowcolor': [('disabled', '#a3a3a3')]},
        'classic': {'fieldbackground': [('readonly', '#d9d9d9'), ('disabled', '#d9d9d9')]},
        'vista': {'focusfill': [('readonly', 'focus', 'SystemHighlight')],
                  'foreground': [('disabled', 'SystemGrayText'),
                                 ('readonly', 'focus', 'SystemHighlightText')],
                  'selectforeground': [('!focus', 'SystemWindowText')],
                  'selectbackground': [('!focus', 'SystemWindow')]},
        'xpnative': {'focusfill': [('readonly', 'focus', 'SystemHighlight')],
                     'foreground': [('disabled', 'SystemGrayText'),
                                    ('readonly', 'focus', 'SystemHighlightText')],
                     'selectforeground': [('!focus', 'SystemWindowText')],
                     'selectbackground': [('!focus', 'SystemWindow')]}}



class Calendar(ttk.Frame):
    """Calendar widget."""
    date = calendar.datetime.date
    datetime = calendar.datetime.datetime
    timedelta = calendar.datetime.timedelta
    strptime = calendar.datetime.datetime.strptime
    strftime = calendar.datetime.datetime.strftime

    def __init__(self, master=None, **kw):
        curs = kw.pop("cursor", "")
        font = kw.pop("font", "Liberation\\ Sans 9")
        classname = kw.pop('class_', "Calendar")
        name = kw.pop('name', None)
        ttk.Frame.__init__(self, master, class_=classname, cursor=curs, name=name)
        self._style_prefixe = str(self)
        ttk.Frame.configure(self, style='main.%s.TFrame' % self._style_prefixe)

        self._textvariable = kw.pop("textvariable", None)

        self._font = Font(self, font)
        prop = self._font.actual()
        prop["size"] += 1
        self._header_font = Font(self, **prop)

        # state
        state = kw.get('state', 'normal')
        try:
            bd = int(kw.pop('borderwidth', 2))
        except ValueError:
            raise ValueError("expected integer for the 'borderwidth' option.")

        firstweekday = kw.pop('firstweekday', 'monday')
        if firstweekday not in ["monday", "sunday"]:
            raise ValueError("'firstweekday' option should be 'monday' or 'sunday'.")
        self._cal = calendar.TextCalendar((firstweekday == 'sunday') * 6)

        weekenddays = kw.pop("weekenddays", None)
        if not weekenddays:
            l = list(self._cal.iterweekdays())
            weekenddays = [l.index(5) + 1, l.index(6) + 1]  # saturday and sunday
        self._check_weekenddays(weekenddays)

        # --- locale
        locale = kw.pop("locale", default_locale())
        if locale is None:
            locale = 'en'
        self._day_names = get_day_names('abbreviated', locale=locale)
        self._month_names = get_month_names('wide', locale=locale)
        date_pattern = self._get_date_pattern(kw.pop("date_pattern", "short"), locale)

        # --- date
        today = self.date.today()

        if self._textvariable is not None:
            # the variable overrides day, month and year keywords
            try:
                self._sel_date = parse_date(self._textvariable.get(), locale)
                month = self._sel_date.month
                year = self._sel_date.year
            except IndexError:
                self._sel_date = None
                self._textvariable.set('')
                month = kw.pop("month", today.month)
                year = kw.pop('year', today.year)
        else:
            if (("month" in kw) or ("year" in kw)) and ("day" not in kw):
                month = kw.pop("month", today.month)
                year = kw.pop('year', today.year)
                self._sel_date = None  # selected day
            else:
                day = kw.pop('day', today.day)
                month = kw.pop("month", today.month)
                year = kw.pop('year', today.year)
                try:
                    self._sel_date = self.date(year, month, day)  # selected day
                except ValueError:
                    self._sel_date = None

        self._date = self.date(year, month, 1)  # (year, month) displayed by the calendar

        # --- date limits
        maxdate = kw.pop('maxdate', None)
        mindate = kw.pop('mindate', None)
        if maxdate is not None:
            if isinstance(maxdate, self.datetime):
                maxdate = maxdate.date()
            elif not isinstance(maxdate, self.date):
                raise TypeError("expected %s for the 'maxdate' option." % self.date)
        if mindate is not None:
            if isinstance(mindate, self.datetime):
                mindate = mindate.date()
            elif not isinstance(mindate, self.date):
                raise TypeError("expected %s for the 'mindate' option." % self.date)
        if (mindate is not None) and (maxdate is not None) and (mindate > maxdate):
            raise ValueError("mindate should be smaller than maxdate.")

        # --- selectmode
        selectmode = kw.pop("selectmode", "day")
        if selectmode not in ("none", "day"):
            raise ValueError("'selectmode' option should be 'none' or 'day'.")
        # --- show week numbers
        showweeknumbers = kw.pop('showweeknumbers', True)

        # --- style
        self.style = ttk.Style(self)
        active_bg = self.style.lookup('TEntry', 'selectbackground', ('focus',))
        dis_active_bg = self.style.lookup('TEntry', 'selectbackground', ('disabled',))
        dis_bg = self.style.lookup('TLabel', 'background', ('disabled',))
        dis_fg = self.style.lookup('TLabel', 'foreground', ('disabled',))

        # --- properties
        options = ['cursor',
                   'font',
                   'borderwidth',
                   'state',
                   'selectmode',
                   'textvariable',
                   'locale',
                   'date_pattern',
                   'maxdate',
                   'mindate',
                   'showweeknumbers',
                   'showothermonthdays',
                   'firstweekday',
                   'weekenddays',
                   'selectbackground',
                   'selectforeground',
                   'disabledselectbackground',
                   'disabledselectforeground',
                   'normalbackground',
                   'normalforeground',
                   'background',
                   'foreground',
                   'disabledbackground',
                   'disabledforeground',
                   'bordercolor',
                   'othermonthforeground',
                   'othermonthbackground',
                   'othermonthweforeground',
                   'othermonthwebackground',
                   'weekendbackground',
                   'weekendforeground',
                   'headersbackground',
                   'headersforeground',
                   'disableddaybackground',
                   'disableddayforeground']

        keys = list(kw.keys())
        for option in keys:
            if option not in options:
                del(kw[option])

        self._properties = {"cursor": curs,
                            "font": font,
                            "borderwidth": bd,
                            "state": state,
                            "locale": locale,
                            "date_pattern": date_pattern,
                            "selectmode": selectmode,
                            'textvariable': self._textvariable,
                            'firstweekday': firstweekday,
                            'weekenddays': weekenddays,
                            'mindate': mindate,
                            'maxdate': maxdate,
                            'showweeknumbers': showweeknumbers,
                            'showothermonthdays': kw.pop('showothermonthdays', True),
                            'selectbackground': active_bg,
                            'selectforeground': 'white',
                            'disabledselectbackground': dis_active_bg,
                            'disabledselectforeground': 'white',
                            'normalbackground': 'white',
                            'normalforeground': 'black',
                            'background': 'gray30',
                            'foreground': 'white',
                            'disabledbackground': 'gray30',
                            'disabledforeground': 'gray70',
                            'bordercolor': 'gray70',
                            'othermonthforeground': 'gray45',
                            'othermonthbackground': 'gray93',
                            'othermonthweforeground': 'gray45',
                            'othermonthwebackground': 'gray75',
                            'weekendbackground': 'gray80',
                            'weekendforeground': 'gray30',
                            'headersbackground': 'gray70',
                            'headersforeground': 'black',
                            'disableddaybackground': dis_bg,
                            'disableddayforeground': dis_fg}
        self._properties.update(kw)

        # --- calevents
        self.calevents = {}  # special events displayed in colors and with tooltips to show content
        self._calevent_dates = {}  # list of event ids for each date
        self._tags = {}  # tags to format event display

        # --- init calendar
        # --- *-- header: month - year
        self._header = ttk.Frame(self, style='main.%s.TFrame' % self._style_prefixe)

        f_month = ttk.Frame(self._header,
                            style='main.%s.TFrame' % self._style_prefixe)
        self._l_month = ttk.Button(f_month,
                                   style='L.%s.TButton' % self._style_prefixe,
                                   command=self._prev_month)
        self._header_month = ttk.Label(f_month, width=10, anchor='center',
                                       style='main.%s.TLabel' % self._style_prefixe, font=self._header_font)
        self._r_month = ttk.Button(f_month,
                                   style='R.%s.TButton' % self._style_prefixe,
                                   command=self._next_month)
        self._l_month.pack(side='left', fill="y")
        self._header_month.pack(side='left', padx=4)
        self._r_month.pack(side='left', fill="y")

        f_year = ttk.Frame(self._header, style='main.%s.TFrame' % self._style_prefixe)
        self._l_year = ttk.Button(f_year, style='L.%s.TButton' % self._style_prefixe,
                                  command=self._prev_year)
        self._header_year = ttk.Label(f_year, width=4, anchor='center',
                                      style='main.%s.TLabel' % self._style_prefixe, font=self._header_font)
        self._r_year = ttk.Button(f_year, style='R.%s.TButton' % self._style_prefixe,
                                  command=self._next_year)
        self._l_year.pack(side='left', fill="y")
        self._header_year.pack(side='left', padx=4)
        self._r_year.pack(side='left', fill="y")

        f_month.pack(side='left', fill='x')
        f_year.pack(side='right')

        # --- *-- calendar
        self._cal_frame = ttk.Frame(self,
                                    style='cal.%s.TFrame' % self._style_prefixe)

        ttk.Label(self._cal_frame,
                  style='headers.%s.TLabel' % self._style_prefixe).grid(row=0,
                                                                        column=0,
                                                                        sticky="eswn")
        # week day names
        self._week_days = []
        for i, day in enumerate(self._cal.iterweekdays()):
            d = self._day_names[day % 7]
            self._cal_frame.columnconfigure(i + 1, weight=1)
            self._week_days.append(ttk.Label(self._cal_frame,
                                             font=self._font,
                                             style='headers.%s.TLabel' % self._style_prefixe,
                                             anchor="center",
                                             text=d, width=4))
            self._week_days[-1].grid(row=0, column=i + 1, sticky="ew", pady=(0, 1))
        self._week_nbs = []  # week numbers
        self._calendar = []  # days
        for i in range(1, 7):
            self._cal_frame.rowconfigure(i, weight=1)
            wlabel = ttk.Label(self._cal_frame, style='headers.%s.TLabel' % self._style_prefixe,
                               font=self._font, padding=2,
                               anchor="e", width=2)
            self._week_nbs.append(wlabel)
            wlabel.grid(row=i, column=0, sticky="esnw", padx=(0, 1))
            if not showweeknumbers:
                wlabel.grid_remove()
            self._calendar.append([])
            for j in range(1, 8):
                label = ttk.Label(self._cal_frame, style='normal.%s.TLabel' % self._style_prefixe,
                                  font=self._font, anchor="center")
                self._calendar[-1].append(label)
                label.grid(row=i, column=j, padx=(0, 1), pady=(0, 1), sticky="nsew")
                if selectmode == "day":
                    label.bind("<1>", self._on_click)

        # --- *-- pack main elements
        self._header.pack(fill="x", padx=2, pady=2)
        self._cal_frame.pack(fill="both", expand=True, padx=bd, pady=bd)

        self.config(state=state)

        # --- bindings
        self.bind('<<ThemeChanged>>', self._setup_style)

        self._setup_style()
        self._display_calendar()
        self._btns_date_range()
        self._check_sel_date()

        if self._textvariable is not None:
            try:
                self._textvariable_trace_id = self._textvariable.trace_add('write', self._textvariable_trace)
            except AttributeError:
                self._textvariable_trace_id = self._textvariable.trace('w', self._textvariable_trace)

    def __getitem__(self, key):
        """Return the resource value for a KEY given as string."""
        try:
            return self._properties[key]
        except KeyError:
            raise AttributeError("Calendar object has no attribute %s." % key)

    def __setitem__(self, key, value):
        if key not in self._properties:
            raise AttributeError("Calendar object has no attribute %s." % key)
        elif key == 'date_pattern':
            date_pattern = self._get_date_pattern(value)
            self._properties[key] = date_pattern
        else:
            if key == "selectmode":
                if value == "none":
                    for week in self._calendar:
                        for day in week:
                            day.unbind("<1>")
                elif value == "day":
                    for week in self._calendar:
                        for day in week:
                            day.bind("<1>", self._on_click)
                else:
                    raise ValueError("'selectmode' option should be 'none' or 'day'.")
            elif key == "locale":
                self._day_names = get_day_names('abbreviated', locale=value)
                self._month_names = get_month_names('wide', locale=value)
                self._properties['date_pattern'] = self._get_date_pattern("short", value)
                for i, l in enumerate(self._week_days):
                    l.configure(text=self._day_names[i])
                self._header_month.configure(text=self._month_names[self._date.month].title())
            elif key == 'textvariable':
                try:
                    if self._textvariable is not None:
                        self._textvariable.trace_remove('write', self._textvariable_trace_id)
                    if value is not None:
                        self._textvariable_trace_id = value.trace_add('write', self._textvariable_trace)
                except AttributeError:
                    if self._textvariable is not None:
                        self._textvariable.trace_vdelete('w', self._textvariable_trace_id)
                    if value is not None:
                        value.trace('w', self._textvariable_trace)
                self._textvariable = value
                value.set(value.get())
            elif key == 'showweeknumbers':
                if value:
                    for wlabel in self._week_nbs:
                        wlabel.grid()
                else:
                    for wlabel in self._week_nbs:
                        wlabel.grid_remove()
            elif key == 'firstweekday':
                if value not in ["monday", "sunday"]:
                    raise ValueError("'firstweekday' option should be 'monday' or 'sunday'.")
                self._cal.firstweekday = (value == 'sunday') * 6
                for label, day in zip(self._week_days, self._cal.iterweekdays()):
                    label.configure(text=self._day_names[day % 7])
            elif key == 'weekenddays':
                self._check_weekenddays(value)
            elif key == 'borderwidth':
                try:
                    bd = int(value)
                    self._cal_frame.pack_configure(padx=bd, pady=bd)
                except ValueError:
                    raise ValueError('expected integer for the borderwidth option.')
            elif key == 'state':
                if value not in ['normal', 'disabled']:
                    raise ValueError("bad state '%s': must be disabled or normal" % value)
                else:
                    state = '!' * (value == 'normal') + 'disabled'
                    self.state((state,))
                    self._header.state((state,))
                    for child in self._header.children.values():
                        child.state((state,))
                    self._header_month.state((state,))
                    self._header_year.state((state,))
                    self._l_year.state((state,))
                    self._r_year.state((state,))
                    self._l_month.state((state,))
                    self._r_month.state((state,))
                    for child in self._cal_frame.children.values():
                        child.state((state,))
            elif key == "maxdate":
                if value is not None:
                    if isinstance(value, self.datetime):
                        value = value.date()
                    elif not isinstance(value, self.date):
                        raise TypeError("expected %s for the 'maxdate' option." % self.date)

                    mindate = self['mindate']
                    if mindate is not None and mindate > value:
                        self._properties['mindate'] = value
                        self._date = self._date.replace(year=value.year, month=value.month)
                    elif self._date > value:
                        self._date = self._date.replace(year=value.year, month=value.month)
                self._r_month.state(['!disabled'])
                self._r_year.state(['!disabled'])
                self._l_month.state(['!disabled'])
                self._l_year.state(['!disabled'])
            elif key == "mindate":
                if value is not None:
                    if isinstance(value, self.datetime):
                        value = value.date()
                    elif not isinstance(value, self.date):
                        raise TypeError("expected %s for the 'mindate' option." % self.date)
                    maxdate = self['maxdate']
                    if maxdate is not None and maxdate < value:
                        self._properties['maxdate'] = value
                        self._date = self._date.replace(year=value.year, month=value.month)
                    elif self._date < value:
                        self._date = self._date.replace(year=value.year, month=value.month)
                self._r_month.state(['!disabled'])
                self._r_year.state(['!disabled'])
                self._l_month.state(['!disabled'])
                self._l_year.state(['!disabled'])
            elif key == "font":
                font = Font(self, value)
                prop = font.actual()
                self._font.configure(**prop)
                prop["size"] += 1
                self._header_font.configure(**prop)
                size = max(prop["size"], 10)
                self.style.configure('R.%s.TButton' % self._style_prefixe, arrowsize=size)
                self.style.configure('L.%s.TButton' % self._style_prefixe, arrowsize=size)
            elif key == "normalbackground":
                self.style.configure('cal.%s.TFrame' % self._style_prefixe, background=value)
                self.style.configure('normal.%s.TLabel' % self._style_prefixe, background=value)
                self.style.configure('normal_om.%s.TLabel' % self._style_prefixe, background=value)
            elif key == "normalforeground":
                self.style.configure('normal.%s.TLabel' % self._style_prefixe, foreground=value)
            elif key == "bordercolor":
                self.style.configure('cal.%s.TFrame' % self._style_prefixe, background=value)
            elif key == "othermonthforeground":
                self.style.configure('normal_om.%s.TLabel' % self._style_prefixe, foreground=value)
            elif key == "othermonthbackground":
                self.style.configure('normal_om.%s.TLabel' % self._style_prefixe, background=value)
            elif key == "othermonthweforeground":
                self.style.configure('we_om.%s.TLabel' % self._style_prefixe, foreground=value)
            elif key == "othermonthwebackground":
                self.style.configure('we_om.%s.TLabel' % self._style_prefixe, background=value)
            elif key == "selectbackground":
                self.style.configure('sel.%s.TLabel' % self._style_prefixe, background=value)
            elif key == "selectforeground":
                self.style.configure('sel.%s.TLabel' % self._style_prefixe, foreground=value)
            elif key == "disabledselectbackground":
                self.style.map('sel.%s.TLabel' % self._style_prefixe, background=[('disabled', value)])
            elif key == "disabledselectforeground":
                self.style.map('sel.%s.TLabel' % self._style_prefixe, foreground=[('disabled', value)])
            elif key == "disableddaybackground":
                self.style.map('%s.TLabel' % self._style_prefixe, background=[('disabled', value)])
            elif key == "disableddayforeground":
                self.style.map('%s.TLabel' % self._style_prefixe, foreground=[('disabled', value)])
            elif key == "weekendbackground":
                self.style.configure('we.%s.TLabel' % self._style_prefixe, background=value)
                self.style.configure('we_om.%s.TLabel' % self._style_prefixe, background=value)
            elif key == "weekendforeground":
                self.style.configure('we.%s.TLabel' % self._style_prefixe, foreground=value)
            elif key == "headersbackground":
                self.style.configure('headers.%s.TLabel' % self._style_prefixe, background=value)
            elif key == "headersforeground":
                self.style.configure('headers.%s.TLabel' % self._style_prefixe, foreground=value)
            elif key == "background":
                self.style.configure('main.%s.TFrame' % self._style_prefixe, background=value)
                self.style.configure('main.%s.TLabel' % self._style_prefixe, background=value)
                self.style.configure('R.%s.TButton' % self._style_prefixe, background=value,
                                     bordercolor=value,
                                     lightcolor=value, darkcolor=value)
                self.style.configure('L.%s.TButton' % self._style_prefixe, background=value,
                                     bordercolor=value,
                                     lightcolor=value, darkcolor=value)
            elif key == "foreground":
                self.style.configure('R.%s.TButton' % self._style_prefixe, arrowcolor=value)
                self.style.configure('L.%s.TButton' % self._style_prefixe, arrowcolor=value)
                self.style.configure('main.%s.TLabel' % self._style_prefixe, foreground=value)
            elif key == "disabledbackground":
                self.style.map('%s.TButton' % self._style_prefixe,
                               background=[('active', '!disabled', self.style.lookup('TEntry', 'selectbackground', ('focus',))),
                                           ('disabled', value)],)
                self.style.map('main.%s.TFrame' % self._style_prefixe,
                               background=[('disabled', value)])
                self.style.map('main.%s.TLabel' % self._style_prefixe,
                               background=[('disabled', value)])
            elif key == "disabledforeground":
                self.style.map('%s.TButton' % self._style_prefixe,
                               arrowcolor=[('disabled', value)])
                self.style.map('main.%s.TLabel' % self._style_prefixe,
                               foreground=[('disabled', value)])
            elif key == "cursor":
                ttk.Frame.configure(self, cursor=value)
            self._properties[key] = value
            if key in ['showothermonthdays', 'firstweekday', 'weekenddays',
                       'maxdate', 'mindate']:
                self._display_calendar()
                self._check_sel_date()
                self._btns_date_range()

    @staticmethod
    def _check_weekenddays(weekenddays):
        try:
            if len(weekenddays) != 2:
                raise ValueError("weekenddays should be a list of two days.")
            else:
                for d in weekenddays:
                    if d not in range(1, 8):
                        raise ValueError("weekenddays should contain integers between 1 and 7.")
        except TypeError:
            raise TypeError("weekenddays should be a list of two days.")

    def _textvariable_trace(self, *args):
        """Connect StringVar value with selected date."""
        if self._properties.get("selectmode") == "day":
            date = self._textvariable.get()
            if not date:
                self._remove_selection()
                self._sel_date = None
            else:
                try:
                    self._sel_date = self.parse_date(date)
                except Exception:
                    if self._sel_date is None:
                        self._textvariable.set('')
                    else:
                        self._textvariable.set(self.format_date(self._sel_date))
                    raise ValueError("%r is not a valid date." % date)
                else:
                    self._date = self._sel_date.replace(day=1)
                    try:
                        self._display_calendar()
                        self._display_selection()
                    except:
                        pass

    def _setup_style(self, event=None):
        """Configure style."""
        self.style.layout('L.%s.TButton' % self._style_prefixe,
                          [('Button.focus',
                            {'children': [('Button.leftarrow', None)]})])
        self.style.layout('R.%s.TButton' % self._style_prefixe,
                          [('Button.focus',
                            {'children': [('Button.rightarrow', None)]})])
        active_bg = self.style.lookup('TEntry', 'selectbackground', ('focus',))

        sel_bg = self._properties.get('selectbackground')
        sel_fg = self._properties.get('selectforeground')
        dis_sel_bg = self._properties.get('disabledselectbackground')
        dis_sel_fg = self._properties.get('disabledselectforeground')
        dis_day_bg = self._properties.get('disableddaybackground')
        dis_day_fg = self._properties.get('disableddayforeground')
        cal_bg = self._properties.get('normalbackground')
        cal_fg = self._properties.get('normalforeground')
        hd_bg = self._properties.get("headersbackground")
        hd_fg = self._properties.get("headersforeground")
        bg = self._properties.get('background')
        fg = self._properties.get('foreground')
        dis_bg = self._properties.get('disabledbackground')
        dis_fg = self._properties.get('disabledforeground')
        bc = self._properties.get('bordercolor')
        om_fg = self._properties.get('othermonthforeground')
        om_bg = self._properties.get('othermonthbackground')
        omwe_fg = self._properties.get('othermonthweforeground')
        omwe_bg = self._properties.get('othermonthwebackground')
        we_bg = self._properties.get('weekendbackground')
        we_fg = self._properties.get('weekendforeground')

        self.style.configure('main.%s.TFrame' % self._style_prefixe, background=bg)
        self.style.configure('cal.%s.TFrame' % self._style_prefixe, background=bc)
        self.style.configure('main.%s.TLabel' % self._style_prefixe, background=bg, foreground=fg)
        self.style.configure('headers.%s.TLabel' % self._style_prefixe, background=hd_bg,
                             foreground=hd_fg)
        self.style.configure('normal.%s.TLabel' % self._style_prefixe, background=cal_bg,
                             foreground=cal_fg)
        self.style.configure('normal_om.%s.TLabel' % self._style_prefixe, background=om_bg,
                             foreground=om_fg)
        self.style.configure('we_om.%s.TLabel' % self._style_prefixe, background=omwe_bg,
                             foreground=omwe_fg)
        self.style.configure('sel.%s.TLabel' % self._style_prefixe, background=sel_bg,
                             foreground=sel_fg)
        self.style.configure('we.%s.TLabel' % self._style_prefixe, background=we_bg,
                             foreground=we_fg)
        size = max(self._header_font.actual()["size"], 10)
        self.style.configure('%s.TButton' % self._style_prefixe, background=bg,
                             arrowcolor=fg, arrowsize=size, bordercolor=bg,
                             relief="flat", lightcolor=bg, darkcolor=bg)

        self.style.map('%s.TButton' % self._style_prefixe,
                       background=[('active', '!disabled', active_bg), ('disabled', dis_bg)],
                       bordercolor=[('active', active_bg)],
                       relief=[('active', 'flat')],
                       arrowcolor=[('disabled', dis_fg)],
                       darkcolor=[('active', active_bg)],
                       lightcolor=[('active', active_bg)])
        self.style.map('main.%s.TFrame' % self._style_prefixe,
                       background=[('disabled', dis_bg)])
        self.style.map('main.%s.TLabel' % self._style_prefixe,
                       background=[('disabled', dis_bg)],
                       foreground=[('disabled', dis_fg)])
        self.style.map('sel.%s.TLabel' % self._style_prefixe,
                       background=[('disabled', dis_sel_bg)],
                       foreground=[('disabled', dis_sel_fg)])
        self.style.map(self._style_prefixe + '.TLabel',
                       background=[('disabled', dis_day_bg)],
                       foreground=[('disabled', dis_day_fg)])

    # --- display
    def _display_calendar(self):
        """Display the days of the current month (the one in self._date)."""
        year, month = self._date.year, self._date.month

        # update header text (Month, Year)
        header = self._month_names[month]
        self._header_month.configure(text=header.title())
        self._header_year.configure(text=str(year))

        # update calendar shown dates
        if self['showothermonthdays']:
            self._display_days_with_othermonthdays()
        else:
            self._display_days_without_othermonthdays()

        self._display_selection()
        maxdate = self['maxdate']
        mindate = self['mindate']

        if maxdate is not None:
            mi, mj = self._get_day_coords(maxdate)
            if mi is not None:
                for j in range(mj + 1, 7):
                    self._calendar[mi][j].state(['disabled'])
                for i in range(mi + 1, 6):
                    for j in range(7):
                        self._calendar[i][j].state(['disabled'])

        if mindate is not None:
            mi, mj = self._get_day_coords(mindate)
            if mi is not None:
                for j in range(mj):
                    self._calendar[mi][j].state(['disabled'])
                for i in range(mi):
                    for j in range(7):
                        self._calendar[i][j].state(['disabled'])

    def _display_days_without_othermonthdays(self):
        year, month = self._date.year, self._date.month

        cal = self._cal.monthdays2calendar(year, month)
        while len(cal) < 6:
            cal.append([(0, i) for i in range(7)])

        week_days = {i: 'normal.%s.TLabel' % self._style_prefixe for i in range(7)}  # style names depending on the type of day
        week_days[self['weekenddays'][0] - 1] = 'we.%s.TLabel' % self._style_prefixe
        week_days[self['weekenddays'][1] - 1] = 'we.%s.TLabel' % self._style_prefixe
        _, week_nb, d = self._date.isocalendar()
        if d == 7 and self['firstweekday'] == 'sunday':
            week_nb += 1
        modulo = max(week_nb, 52)
        for i_week in range(6):
            if i_week == 0 or cal[i_week][0][0]:
                self._week_nbs[i_week].configure(text=str((week_nb + i_week - 1) % modulo + 1))
            else:
                self._week_nbs[i_week].configure(text='')
            for i_day in range(7):
                day_number, week_day = cal[i_week][i_day]
                style = week_days[i_day]
                label = self._calendar[i_week][i_day]
                label.state(['!disabled'])
                if day_number:
                    txt = str(day_number)
                    label.configure(text=txt, style=style)
                    date = self.date(year, month, day_number)
                    if date in self._calevent_dates:
                        ev_ids = self._calevent_dates[date]
                        i = len(ev_ids) - 1
                        while i >= 0 and not self.calevents[ev_ids[i]]['tags']:
                            i -= 1
                        if i >= 0:
                            tag = self.calevents[ev_ids[i]]['tags'][-1]
                            label.configure(style='tag_%s.%s.TLabel' % (tag, self._style_prefixe))
                        text = '\n'.join(['➢ {}'.format(self.calevents[ev]['text']) for ev in ev_ids])
                else:
                    label.configure(text='', style=style)

    def _display_days_with_othermonthdays(self):
        year, month = self._date.year, self._date.month

        cal = self._cal.monthdatescalendar(year, month)

        next_m = month + 1
        y = year
        if next_m == 13:
            next_m = 1
            y += 1
        if len(cal) < 6:
            if cal[-1][-1].month == month:
                i = 0
            else:
                i = 1
            cal.append(self._cal.monthdatescalendar(y, next_m)[i])
            if len(cal) < 6:
                cal.append(self._cal.monthdatescalendar(y, next_m)[i + 1])

        week_days = {i: 'normal' for i in range(7)}  # style names depending on the type of day
        week_days[self['weekenddays'][0] - 1] = 'we'
        week_days[self['weekenddays'][1] - 1] = 'we'
        prev_m = (month - 2) % 12 + 1
        months = {month: '.%s.TLabel' % self._style_prefixe,
                  next_m: '_om.%s.TLabel' % self._style_prefixe,
                  prev_m: '_om.%s.TLabel' % self._style_prefixe}

        week_nb = cal[0][1].isocalendar()[1]
        modulo = max(week_nb, 52)
        for i_week in range(6):
            self._week_nbs[i_week].configure(text=str((week_nb + i_week - 1) % modulo + 1))
            for i_day in range(7):
                style = week_days[i_day] + months[cal[i_week][i_day].month]
                label = self._calendar[i_week][i_day]
                label.state(['!disabled'])
                txt = str(cal[i_week][i_day].day)
                label.configure(text=txt, style=style)
                if cal[i_week][i_day] in self._calevent_dates:
                    date = cal[i_week][i_day]
                    ev_ids = self._calevent_dates[date]
                    i = len(ev_ids) - 1
                    while i >= 0 and not self.calevents[ev_ids[i]]['tags']:
                        i -= 1
                    if i >= 0:
                        tag = self.calevents[ev_ids[i]]['tags'][-1]
                        label.configure(style='tag_%s.%s.TLabel' % (tag, self._style_prefixe))
                    text = '\n'.join(['➢ {}'.format(self.calevents[ev]['text']) for ev in ev_ids])

    def _get_day_coords(self, date):
        y1, y2 = date.year, self._date.year
        m1, m2 = date.month, self._date.month
        if y1 == y2 or (y1 - y2 == 1 and m1 == 1 and m2 == 12) or (y2 - y1 == 1 and m2 == 1 and m1 == 12):
            _, w, d = date.isocalendar()
            _, wn, dn = self._date.isocalendar()
            if self['firstweekday'] == 'sunday':
                d %= 7
                if d == 0:
                    w += 1
                if dn == 7:
                    wn += 1
            else:
                d -= 1
            w -= wn
            w %= max(52, wn)
            if 0 <= w < 6:
                return w, d
            else:
                return None, None
        else:
            return None, None

    def _display_selection(self):
        """Highlight selected day."""
        if self._sel_date is not None:
            w, d = self._get_day_coords(self._sel_date)
            if w is not None:
                label = self._calendar[w][d]
                if label.cget('text'):
                    label.configure(style='sel.%s.TLabel' % self._style_prefixe)

    def _reset_day(self, date):
        """Restore usual week day colors."""
        month = date.month
        w, d = self._get_day_coords(date)
        if w is not None:
            week_end = [0, 6] if self['firstweekday'] == 'sunday' else [5, 6]
            if month == date.month:
                if d in week_end:
                    self._calendar[w][d].configure(style='we.%s.TLabel' % self._style_prefixe)
                else:
                    self._calendar[w][d].configure(style='normal.%s.TLabel' % self._style_prefixe)
            else:
                if d in week_end:
                    self._calendar[w][d].configure(style='we_om.%s.TLabel' % self._style_prefixe)

                else:
                    self._calendar[w][d].configure(style='normal_om.%s.TLabel' % self._style_prefixe)

    def _remove_selection(self):
        """Remove highlight of selected day."""
        if self._sel_date is not None:
            if self._sel_date in self._calevent_dates:
                self._show_event(self._sel_date)
            else:
                w, d = self._get_day_coords(self._sel_date)
                if w is not None:
                    week_end = [0, 6] if self['firstweekday'] == 'sunday' else [5, 6]
                    if self._sel_date.month == self._date.month:
                        if d in week_end:
                            self._calendar[w][d].configure(style='we.%s.TLabel' % self._style_prefixe)
                        else:
                            self._calendar[w][d].configure(style='normal.%s.TLabel' % self._style_prefixe)
                    else:
                        if d in week_end:
                            self._calendar[w][d].configure(style='we_om.%s.TLabel' % self._style_prefixe)
                        else:
                            self._calendar[w][d].configure(style='normal_om.%s.TLabel' % self._style_prefixe)

    def _show_event(self, date):
        """Display events on date if visible."""
        w, d = self._get_day_coords(date)
        if w is not None:
            label = self._calendar[w][d]
            if not label.cget('text'):
                # this is an other month's day and showothermonth is False
                return
            ev_ids = self._calevent_dates[date]
            i = len(ev_ids) - 1
            while i >= 0 and not self.calevents[ev_ids[i]]['tags']:
                i -= 1
            if i >= 0:
                tag = self.calevents[ev_ids[i]]['tags'][-1]
                label.configure(style='tag_%s.%s.TLabel' % (tag, self._style_prefixe))

    def check_date_range(self, date):
        """
        Ensure that date is in the allowed date range.

            date : datetime.date or datetime.datetime

        Return date if date is in the allowed date range, return the closest
        bound otherwise.
        """
        maxdate = self['maxdate']
        mindate = self['mindate']
        if maxdate is not None and date > maxdate:
            return maxdate
        elif mindate is not None and date < mindate:
            return mindate
        else:
            return date

    def _check_sel_date(self):

        if self._sel_date is not None:
            maxdate = self['maxdate']
            mindate = self['mindate']
            if maxdate is not None and self._sel_date > maxdate:
                self._sel_date = maxdate
                self._display_selection()
            elif mindate is not None and self._sel_date < mindate:
                self._sel_date = mindate
                self._display_selection()

    def _btns_date_range(self):
        """Disable/enable buttons depending on allowed date range."""
        maxdate = self['maxdate']
        mindate = self['mindate']

        if maxdate is not None:
            max_year, max_month = maxdate.year, maxdate.month
            if self._date > maxdate:
                self._date = self._date.replace(year=max_year, month=max_month)
                self._display_calendar()

            dy = max_year - self._date.year
            if dy == 0:
                self._r_year.state(['disabled'])
                if self._date.month == max_month:
                    self._r_month.state(['disabled'])
                else:
                    self._r_month.state(['!disabled'])
            elif dy == 1:
                if self._date.month > max_month:
                    self._r_year.state(['disabled'])
                else:
                    self._r_year.state(['!disabled'])
                    self._r_month.state(['!disabled'])
            else:  # dy > 1
                self._r_year.state(['!disabled'])
                self._r_month.state(['!disabled'])

        if mindate is not None:
            min_year, min_month = mindate.year, mindate.month
            if self._date < mindate:
                self._date = self._date.replace(year=min_year, month=min_month)
                self._display_calendar()

            dy = self._date.year - min_year
            if dy == 0:
                self._l_year.state(['disabled'])
                if self._date.month == min_month:
                    self._l_month.state(['disabled'])
                else:
                    self._l_month.state(['!disabled'])
            elif dy == 1:
                if self._date.month >= min_month:
                    self._l_year.state(['!disabled'])
                    self._l_month.state(['!disabled'])
                else:
                    self._l_year.state(['disabled'])
            else:  # dy > 1
                self._l_year.state(['!disabled'])
                self._l_month.state(['!disabled'])

    # --- callbacks
    def _next_month(self):
        """Display the next month."""
        year, month = self._date.year, self._date.month
        self._date = self._date + \
            self.timedelta(days=calendar.monthrange(year, month)[1])
        self._display_calendar()
        self.event_generate('<<CalendarMonthChanged>>')
        self._btns_date_range()

    def _prev_month(self):
        """Display the previous month."""
        self._date = self._date - self.timedelta(days=1)
        self._date = self._date.replace(day=1)
        self._display_calendar()
        self.event_generate('<<CalendarMonthChanged>>')
        self._btns_date_range()

    def _next_year(self):
        """Display the next year."""
        year = self._date.year
        self._date = self._date.replace(year=year + 1)
        self._display_calendar()
        self.event_generate('<<CalendarMonthChanged>>')
        self._btns_date_range()

    def _prev_year(self):
        """Display the previous year."""
        year = self._date.year
        self._date = self._date.replace(year=year - 1)
        self._display_calendar()
        self.event_generate('<<CalendarMonthChanged>>')
        self._btns_date_range()

    # --- bindings
    def _on_click(self, event):
        """Select the day on which the user clicked."""
        if self._properties['state'] == 'normal':
            label = event.widget
            if "disabled" not in label.state():
                day = label.cget("text")
                style = label.cget("style")
                if style in ['normal_om.%s.TLabel' % self._style_prefixe, 'we_om.%s.TLabel' % self._style_prefixe]:
                    if label in self._calendar[0]:
                        self._prev_month()
                    else:
                        self._next_month()
                if day:
                    day = int(day)
                    year, month = self._date.year, self._date.month
                    self._remove_selection()
                    self._sel_date = self.date(year, month, day)
                    self._display_selection()
                    if self._textvariable is not None:
                        self._textvariable.set(self.format_date(self._sel_date))
                    self.event_generate("<<CalendarSelected>>")

    def _get_date_pattern(self, date_pattern, locale=None):
        """
        Return the babel pattern corresponding to date_pattern.

        If date_pattern is "short", return the pattern correpsonding to the
        locale, else return date_pattern if valid.

        A valid pattern is a sequence of y, m and d
        separated by non letter characters, e.g. yyyy-mm-dd or d/m/yy
        """
        if locale is None:
            locale = self._properties["locale"]
        if date_pattern == "short":
            return get_date_format("short", locale).pattern
        pattern = date_pattern.lower()
        ymd = r"^y+[^a-zA-Z]*m{1,2}[^a-z]*d{1,2}[^mdy]*$"
        mdy = r"^m{1,2}[^a-zA-Z]*d{1,2}[^a-z]*y+[^mdy]*$"
        dmy = r"^d{1,2}[^a-zA-Z]*m{1,2}[^a-z]*y+[^mdy]*$"
        res = ((re.search(ymd, pattern) is not None)
               or (re.search(mdy, pattern) is not None)
               or (re.search(dmy, pattern) is not None))
        if res:
            return pattern.replace('m', 'M')
        raise ValueError("%r is not a valid date pattern" % date_pattern)

    def format_date(self, date=None):
        """Convert date (datetime.date) to a string in the locale."""
        return format_date(date, self._properties['date_pattern'], self._properties['locale'])

    def parse_date(self, date):
        """Parse string date in the locale format and return the corresponding datetime.date."""
        date_format = self._properties['date_pattern'].lower()
        year_idx = date_format.index('y')
        month_idx = date_format.index('m')
        day_idx = date_format.index('d')

        indexes = [(year_idx, 'Y'), (month_idx, 'M'), (day_idx, 'D')]
        indexes.sort()
        indexes = dict([(item[1], idx) for idx, item in enumerate(indexes)])

        numbers = re.findall(r'(\d+)', date)
        year = numbers[indexes['Y']]
        if len(year) == 2:
            year = 2000 + int(year)
        else:
            year = int(year)
        month = int(numbers[indexes['M']])
        day = int(numbers[indexes['D']])
        if month > 12:
            month, day = day, month
        return self.date(year, month, day)

    def see(self, date):
        """
        Display the month in which date is.


            date : datetime.date or datetime.datetime
                date to be made visible
        """
        if isinstance(date, self.datetime):
            date = date.date()
        elif not isinstance(date, self.date):
            raise TypeError("expected %s for the 'date' argument." % self.date)

        self._date = self._date.replace(month=date.month, year=date.year)
        self._display_calendar()
        self._btns_date_range()

    # --- selection handling
    def selection_clear(self):
        """Clear the selection."""
        self._remove_selection()
        self._sel_date = None
        if self._textvariable is not None:
            self._textvariable.set('')

    def selection_get(self):
        """
        Return currently selected date (datetime.date instance).

        Always return None if selectmode == "none".
        """

        if self._properties.get("selectmode") == "day":
            return self._sel_date
        else:
            return None

    def selection_set(self, date):
        """
        Set the selection to date.

            date : datetime.date, datetime.datetime or str
                    date to be made visible. If given as a string, it should be
                    in the format corresponding to the calendar locale.

        Do nothing if selectmode == "none".
        """
        if self._properties.get("selectmode") == "day" and self._properties['state'] == 'normal':
            if date is None:
                self.selection_clear()
            else:
                if isinstance(date, self.datetime):
                    self._sel_date = date.date()
                elif isinstance(date, self.date):
                    self._sel_date = date
                else:
                    try:
                        self._sel_date = self.parse_date(date)
                    except Exception as e:
                        raise ValueError("%r is not a valid date." % date)
                if self['mindate'] is not None and self._sel_date < self['mindate']:
                    self._sel_date = self['mindate']
                elif self['maxdate'] is not None and self._sel_date > self['maxdate']:
                    self._sel_date = self['maxdate']
                if self._textvariable is not None:
                    self._textvariable.set(self.format_date(self._sel_date))

                self._date = self._sel_date.replace(day=1)
                self._display_calendar()
                self._display_selection()
                self._btns_date_range()

    def get_displayed_month(self):
        """Return the currently displayed month in the form of a (month, year) tuple."""
        return self._date.month, self._date.year

    def get_date(self):
        """Return selected date as string."""
        if self._sel_date is not None:
            return self.format_date(self._sel_date)
        else:
            return ""

    # --- events
    def calevent_create(self, date, text, tags=[]):
        """
        Add new event in calendar and return event id.

        Options:

            date : datetime.date or datetime.datetime
                event date

            text : str
                text to put in the tooltip associated to date.

            tags : list
                list of tags to apply to the event. The last tag determines
                the way the event is displayed. If there are several events on
                the same day, the lowest one (on the tooltip list) which has
                tags determines the colors of the day.
        """
        if isinstance(date, Calendar.datetime):
            date = date.date()
        if not isinstance(date, Calendar.date):
            raise TypeError("date option should be a %s instance" % (Calendar.date))
        if self.calevents:
            ev_id = max(self.calevents) + 1
        else:
            ev_id = 0
        if isinstance(tags, str):
            tags_ = [tags]
        else:
            tags_ = list(tags)
        self.calevents[ev_id] = {'date': date, 'text': text, 'tags': tags_}
        for tag in tags_:
            if tag not in self._tags:
                self._tag_initialize(tag)
        if date not in self._calevent_dates:
            self._calevent_dates[date] = [ev_id]
        else:
            self._calevent_dates[date].append(ev_id)
        self._show_event(date)
        return ev_id

    def _calevent_remove(self, ev_id):
        """Remove event ev_id."""
        try:
            date = self.calevents[ev_id]['date']
        except KeyError:
            ValueError("event %s does not exists" % ev_id)
        else:
            del self.calevents[ev_id]
            self._calevent_dates[date].remove(ev_id)
            if not self._calevent_dates[date]:
                del self._calevent_dates[date]
                self._reset_day(date)
            else:
                self._show_event(date)

    def calevent_remove(self, *ev_ids, **kw):
        """
        Remove events from calendar.

        Arguments: event ids to remove or 'all' to remove them all.

        Keyword arguments: tag, date.

            They are taken into account only if no id is given. Remove all events
            with given tag on given date. If only date is given, remove all events
            on date and if only tag is given, remove all events with tag.
        """
        if ev_ids:
            if 'all' in ev_ids:
                ev_ids = self.get_calevents()
            for ev_id in ev_ids:
                self._calevent_remove(ev_id)
        else:
            date = kw.get('date')
            tag = kw.get('tag')
            evs = self.get_calevents(tag=tag, date=date)
            for ev_id in evs:
                self._calevent_remove(ev_id)

    def calevent_cget(self, ev_id, option):
        """Return value of given option for the event ev_id."""
        try:
            ev = self.calevents[ev_id]
        except KeyError:
            raise ValueError("event %s does not exists" % ev_id)
        else:
            try:
                return ev[option]
            except KeyError:
                raise ValueError('unknown option "%s"' % option)

    def calevent_configure(self, ev_id, **kw):
        """
        Configure the event ev_id.

        Keyword options: date, text, tags (see calevent_create options).
        """
        try:
            ev = self.calevents[ev_id]
        except KeyError:
            raise ValueError("event %s does not exists" % ev_id)
        else:
            text = kw.pop('text', None)
            tags = kw.pop('tags', None)
            date = kw.pop('date', None)
            if kw:
                raise KeyError('Invalid keyword option(s) %s, valid options are "text", "tags" and "date".' % (kw.keys(),))
            else:
                if text is not None:
                    ev['text'] = str(text)
                if tags is not None:
                    if isinstance(tags, str):
                        tags_ = [tags]
                    else:
                        tags_ = list(tags)
                    for tag in tags_:
                        if tag not in self._tags:
                            self._tag_initialize(tag)
                    ev['tags'] = tags_
                if date is not None:
                    if isinstance(date, Calendar.datetime):
                        date = date.date()
                    if not isinstance(date, Calendar.date):
                        raise TypeError("date option should be a %s instance" % (Calendar.date))
                    old_date = ev['date']
                    self._calevent_dates[old_date].remove(ev_id)
                    if not self._calevent_dates[old_date]:
                        self._reset_day(old_date)
                    else:
                        self._show_event(old_date)
                    ev['date'] = date
                    if date not in self._calevent_dates:
                        self._calevent_dates[date] = [ev_id]
                    else:
                        self._calevent_dates[date].append(ev_id)
                self._show_event(ev['date'])

    def calevent_raise(self, ev_id, above=None):
        """
        Raise event ev_id in tooltip event list.

            above : str
                put ev_id above given one, if above is None, put it on top
                of tooltip event list.

        The day's colors are determined by the last tag of the lowest event
        which has tags.
        """
        try:
            date = self.calevents[ev_id]['date']
        except KeyError:
            raise ValueError("event %s does not exists" % ev_id)
        else:
            evs = self._calevent_dates[date]
            if above is None:
                evs.remove(ev_id)
                evs.insert(0, ev_id)
            else:
                if above not in evs:
                    raise ValueError("event %s does not exists on %s" % (above, date))
                else:
                    evs.remove(ev_id)
                    index = evs.index(above)
                    evs.insert(index, ev_id)
            self._show_event(date)

    def calevent_lower(self, ev_id, below=None):
        """
        Lower event ev_id in tooltip event list.

            below : str
                put ev_id below given one, if below is None, put it at the
                bottom of tooltip event list.

        The day's colors are determined by the last tag of the lowest event
        which has tags.
        """
        try:
            date = self.calevents[ev_id]['date']
        except KeyError:
            raise ValueError("event %s does not exists" % ev_id)
        else:
            evs = self._calevent_dates[date]
            if below is None:
                evs.remove(ev_id)
                evs.append(ev_id)
            else:
                if below not in evs:
                    raise ValueError("event %s does not exists on %s" % (below, date))
                else:
                    evs.remove(ev_id)
                    index = evs.index(below) + 1
                    evs.insert(index, ev_id)
            self._show_event(date)

    def get_calevents(self, date=None, tag=None):
        """
        Return event ids of events with given tag and on given date.

        If only date is given, return event ids of all events on date.
        If only tag is given, return event ids of all events with tag.
        If both options are None, return all event ids.
        """
        if date is not None:
            if isinstance(date, Calendar.datetime):
                date = date.date()
            if not isinstance(date, Calendar.date):
                raise TypeError("date option should be a %s instance" % (Calendar.date))
            try:
                if tag is not None:
                    return tuple(ev_id for ev_id in self._calevent_dates[date] if tag in self.calevents[ev_id]['tags'])
                else:
                    return tuple(self._calevent_dates[date])
            except KeyError:
                return ()
        elif tag is not None:
            return tuple(ev_id for ev_id, prop in self.calevents.items() if tag in prop['tags'])
        else:
            return tuple(self.calevents.keys())

    def _tag_initialize(self, tag):
        props = dict(foreground='white', background='royal blue')
        self._tags[tag] = props
        self.style.configure('tag_%s.%s.TLabel' % (tag, self._style_prefixe), **props)

    def tag_config(self, tag, **kw):
        """
        Configure tag.

        Keyword options: foreground, background (of the day in the calendar)
        """
        if tag not in self._tags:
            self._tags[tag] = {}
        props = dict(foreground='white', background='royal blue')  # default
        props.update(self._tags[tag])
        props.update(kw)
        self.style.configure('tag_%s.%s.TLabel' % (tag, self._style_prefixe), **props)
        self._tags[tag] = props

    def tag_cget(self, tag, option):
        """Return the value of the tag's option."""
        try:
            prop = self._tags[tag]
        except KeyError:
            raise ValueError('unknow tag "%s"' % tag)
        else:
            try:
                return prop[option]
            except KeyError:
                raise ValueError('unknow option "%s"' % option)

    def tag_names(self):
        """Return tuple of existing tags."""
        return tuple(self._tags.keys())

    def tag_delete(self, tag):
        """
        Delete given tag.

        Delete tag properties and remove tag from all events.
        """
        try:
            del self._tags[tag]
        except KeyError:
            raise ValueError('tag "%s" does not exists' % tag)
        else:
            for props in self.calevents.values():
                if tag in props['tags']:
                    props['tags'].remove(tag)
            self._display_calendar()

    # --- other methods
    def keys(self):
        """Return a list of all resource names of this widget."""
        return list(self._properties.keys())

    def cget(self, key):
        """Return the resource value for a KEY given as string."""
        return self[key]

    def configure(self, cnf={}, **kw):
        """
        Configure resources of a widget.

        The values for resources are specified as keyword
        arguments. To get an overview about
        the allowed keyword arguments call the method :meth:`~Calendar.keys`.
        """
        if not isinstance(cnf, dict):
            raise TypeError("Expected a dictionary or keyword arguments.")
        kwargs = cnf.copy()
        kwargs.update(kw)
        for item, value in kwargs.items():
            self[item] = value

    config = configure


class DateEntry(ttk.Entry):

    entry_kw = {'exportselection': 1,
                'invalidcommand': '',
                'justify': 'left',
                'show': '',
                'cursor': 'xterm',
                'style': '',
                'state': 'normal',
                'takefocus': 'ttk::takefocus',
                'validate': 'none',
                'validatecommand': '',
                'width': 12,
                'xscrollcommand': ''}

    def __init__(self, master=None, **kw):
        # sort keywords between entry options and calendar options
        kw['selectmode'] = 'day'
        entry_kw = {}
        for key in self.entry_kw:
            entry_kw[key] = kw.pop(key, self.entry_kw[key])
        entry_kw['font'] = kw.get('font', None)
        self._cursor = entry_kw['cursor']  # entry cursor
        self._mouse_x, self._mouse_y = 0, 0
        kw['cursor'] = kw.pop('calendar_cursor', None)
        ttk.Entry.__init__(self, master, **entry_kw)
        self._determine_downarrow_name_after_id = ''

        # drop-down calendar
        self._top_cal = tk.Toplevel(self)
        self._top_cal.withdraw()
        if platform == "linux":
            self._top_cal.attributes('-type', 'DROPDOWN_MENU')
        self._top_cal.overrideredirect(True)
        self._calendar = Calendar(self._top_cal, **kw)
        self._calendar.pack()

        # locale date parsing / formatting
        self.format_date = self._calendar.format_date
        self.parse_date = self._calendar.parse_date

        # style
        self.style = ttk.Style(self)
        self._setup_style()
        self.configure(style='DateEntry')

        # add validation to Entry so that only dates in the locale's format are accepted
        validatecmd = self.register(self._validate_date)
        self.configure(validate='focusout', validatecommand=validatecmd)

        # initially selected date
        self._date = self._calendar.selection_get()
        if self._date is None:
            today = self._calendar.date.today()
            year = kw.get('year', today.year)
            month = kw.get('month', today.month)
            day = kw.get('day', today.day)
            try:
                self._date = self._calendar.date(year, month, day)
            except ValueError:
                self._date = today
        self._set_text(self.format_date(self._date))

        # --- bindings
        # determine new downarrow button bbox
        self.bind('<Configure>', self._determine_downarrow_name)
        self.bind('<Map>', self._determine_downarrow_name)
        # handle appearence to make the entry behave like a Combobox but with
        # a drop-down calendar instead of a drop-down list
        self.bind('<Leave>', lambda e: self.state(['!active']))
        self.bind('<Motion>', self._on_motion)
        self.bind('<ButtonPress-1>', self._on_b1_press)
        # update entry content when date is selected in the Calendar
        self._calendar.bind('<<CalendarSelected>>', self._select)
        # hide calendar if it looses focus
        self._top_cal.bind('<FocusOut>', self._on_focus_out_cal)

    def __getitem__(self, key):
        return self.cget(key)

    def __setitem__(self, key, value):
        self.configure(**{key: value})

    def _setup_style(self, event=None):
        self.style.layout('DateEntry', self.style.layout('TCombobox'))
        self.update_idletasks()
        conf = self.style.configure('TCombobox')
        if conf:
            self.style.configure('DateEntry', **conf)
        maps = self.style.map('TCombobox')
        if maps:
            try:
                self.style.map('DateEntry', **maps)
            except tk.TclError:
                maps = MAPS.get(self.style.theme_use(), MAPS['default'])
                self.style.map('DateEntry', **maps)
        try:
            self.after_cancel(self._determine_downarrow_name_after_id)
        except ValueError:
            pass
        self._determine_downarrow_name_after_id = self.after(10, self._determine_downarrow_name)

    def _determine_downarrow_name(self, event=None):
        try:
            self.after_cancel(self._determine_downarrow_name_after_id)
        except ValueError:
            pass
        if self.winfo_ismapped():
            self.update_idletasks()
            y = self.winfo_height() // 2
            x = self.winfo_width() - 10
            name = self.identify(x, y)
            if name:
                self._downarrow_name = name
            else:
                self._determine_downarrow_name_after_id = self.after(10, self._determine_downarrow_name)

    def _on_motion(self, event):
        self._mouse_x, self._mouse_y = event.x, event.y
        if 'disabled' not in self.state():
            if self.identify(self._mouse_x, self._mouse_y) == self._downarrow_name:
                self.state(['active'])
                ttk.Entry.configure(self, cursor='arrow')
            else:
                self.state(['!active'])
                ttk.Entry.configure(self, cursor=self._cursor)

    def _on_b1_press(self, event):
        x, y = event.x, event.y
        if (('disabled' not in self.state()) and self.identify(x, y) == self._downarrow_name):
            self.state(['pressed'])
            self.drop_down()

    def _on_focus_out_cal(self, _event):
        if self.focus_get() is not None:
            if self.focus_get() == self:
                if self.identify(self._mouse_x, self._mouse_y) != self._downarrow_name:
                    self._top_cal.withdraw()
                    self.state(['!pressed'])
                elif 'pressed' in self.state():
                    self._top_cal.withdraw()
                    self._top_cal.deiconify()
                    self._top_cal.focus_force()
        else:
            if 'active' in self.state():
                self._top_cal.focus_force()
            else:
                self._top_cal.withdraw()
                self.state(['!pressed'])

    def _validate_date(self):
        try:
            date = self.parse_date(self.get())
            self._date = self._calendar.check_date_range(date)
            if self._date != date:
                self._set_text(self.format_date(self._date))
                return False
            else:
                return True
        except (ValueError, IndexError):
            self._set_text(self.format_date(self._date))
            return False

    def _select(self, event=None):
        date = self._calendar.selection_get()
        if date is not None:
            self._set_text(self.format_date(date))
            self._date = date
            self.event_generate('<<DateEntrySelected>>')
        self._top_cal.withdraw()
        self.state(['!pressed'])
        if 'readonly' not in self.state():
            self.focus_set()

    def _set_text(self, txt):
        if 'readonly' in self.state():
            readonly = True
            self.state(('!readonly',))
        else:
            readonly = False
        self.delete(0, 'end')
        self.insert(0, txt)
        if readonly:
            self.state(('readonly',))

    def destroy(self):
        try:
            self.after_cancel(self._determine_downarrow_name_after_id)
        except ValueError:
            # nothing to cancel
            pass
        ttk.Entry.destroy(self)

    def drop_down(self):
        if self._calendar.winfo_ismapped():
            self._top_cal.withdraw()
        else:
            self._validate_date()
            date = self.parse_date(self.get())
            x = self.winfo_rootx()
            y = self.winfo_rooty() + self.winfo_height()
            if self.winfo_toplevel().attributes('-topmost'):
                self._top_cal.attributes('-topmost', True)
            else:
                self._top_cal.attributes('-topmost', False)
            self._top_cal.geometry('+%i+%i' % (x, y))
            self._top_cal.deiconify()
            self._top_cal.focus_set()
            self._calendar.selection_set(date)

    def state(self, *args):
        if args:
            # change cursor depending on state to mimic Combobox behavior
            states = args[0]
            if 'disabled' in states or 'readonly' in states:
                self.configure(cursor='arrow')
            elif '!disabled' in states or '!readonly' in states:
                self.configure(cursor='xterm')
        return ttk.Entry.state(self, *args)

    def keys(self):
        keys = list(self.entry_kw)
        keys.extend(self._calendar.keys())
        keys.append('calendar_cursor')
        return list(set(keys))

    def cget(self, key):
        if key in self.entry_kw:
            return ttk.Entry.cget(self, key)
        elif key == 'calendar_cursor':
            return self._calendar.cget('cursor')
        else:
            return self._calendar.cget(key)

    def configure(self, cnf={}, **kw):
        if not isinstance(cnf, dict):
            raise TypeError("Expected a dictionary or keyword arguments.")
        kwargs = cnf.copy()
        kwargs.update(kw)

        entry_kw = {}
        keys = list(kwargs.keys())
        for key in keys:
            if key in self.entry_kw:
                entry_kw[key] = kwargs.pop(key)
        font = kwargs.get('font', None)
        if font is not None:
            entry_kw['font'] = font
        self._cursor = str(entry_kw.get('cursor', self._cursor))
        if entry_kw.get('state') == 'readonly' and self._cursor == 'xterm' and 'cursor' not in entry_kw:
            entry_kw['cursor'] = 'arrow'
            self._cursor  = 'arrow'
        ttk.Entry.configure(self, entry_kw)

        kwargs['cursor'] = kwargs.pop('calendar_cursor', None)
        self._calendar.configure(kwargs)
        if 'date_pattern' in kwargs or 'locale' in kwargs:
            self._set_text(self.format_date(self._date))

    config = configure

    def set_date(self, date):
        try:
            txt = self.format_date(date)
        except AssertionError:
            txt = str(date)
            try:
                self.parse_date(txt)
            except Exception:
                raise ValueError("%r is not a valid date." % date)
        self._set_text(txt)
        self._validate_date()

    def get_date(self):
        self._validate_date()
        return self.parse_date(self.get())
