# -*- coding: utf-8 -*-
import calendar
import tkinter as tk
import tkinter.font as tkFont
from tkinter import ttk

datetime = calendar.datetime.datetime
timedelta = calendar.datetime.timedelta


class Calendar:

    def __init__(s, point=None, position=None):
        # point    提供一个基点，来确定窗口位置
        # position 窗口在点的位置 'ur'-右上, 'ul'-左上, 'll'-左下, 'lr'-右下
        # s.master = tk.Tk()
        s.master = tk.Toplevel()
        s.master.withdraw()
        fwday = calendar.SUNDAY

        year = datetime.now().year
        month = datetime.now().month
        locale = None
        sel_bg = '#ecffc4'
        sel_fg = '#05640e'

        s._date = datetime(year, month, 1)
        s._selection = None  # 设置为未选中日期

        s.G_Frame = ttk.Frame(s.master)

        s._cal = s.__get_calendar(locale, fwday)

        s.__setup_styles()  # 创建自定义样式
        s.__place_widgets()  # pack/grid 小部件
        s.__config_calendar()  # 调整日历列和安装标记
        # 配置画布和正确的绑定，以选择日期。
        s.__setup_selection(sel_bg, sel_fg)

        # 存储项ID，用于稍后插入。
        s._items = [s._calendar.insert('', 'end', values='') for _ in range(6)]

        # 在当前空日历中插入日期
        s._update()

        s.G_Frame.pack(expand=1, fill='both')
        s.master.overrideredirect(1)
        s.master.update_idletasks()
        width, height = s.master.winfo_reqwidth(), s.master.winfo_reqheight()
        if point and position:
            if position == 'ur':
                x, y = point[0], point[1] - height
            elif position == 'lr':
                x, y = point[0], point[1]
            elif position == 'ul':
                x, y = point[0] - width, point[1] - height
            elif position == 'll':
                x, y = point[0] - width, point[1]
        else:
            x, y = (s.master.winfo_screenwidth() - width) / 2, (s.master.winfo_screenheight() - height) / 2
        s.master.geometry('%dx%d+%d+%d' % (width, height, x, y))  # 窗口位置居中
        s.master.after(300, s._main_judge)
        s.master.deiconify()
        s.master.focus_set()
        s.master.wait_window()  # 这里应该使用wait_window挂起窗口，如果使用mainloop,可能会导致主程序很多错误

    def __get_calendar(s, locale, fwday):
        # 实例化适当的日历类
        if locale is None:
            return calendar.TextCalendar(fwday)
        else:
            return calendar.LocaleTextCalendar(fwday, locale)

    def __setitem__(s, item, value):
        if item in ('year', 'month'):
            raise AttributeError("attribute '%s' is not writeable" % item)
        elif item == 'selectbackground':
            s._canvas['background'] = value
        elif item == 'selectforeground':
            s._canvas.itemconfigure(s._canvas.text, item=value)
        else:
            s.G_Frame.__setitem__(s, item, value)

    def __getitem__(s, item):
        if item in ('year', 'month'):
            return getattr(s._date, item)
        elif item == 'selectbackground':
            return s._canvas['background']
        elif item == 'selectforeground':
            return s._canvas.itemcget(s._canvas.text, 'fill')
        else:
            r = ttk.tclobjs_to_py({item: ttk.Frame.__getitem__(s, item)})
            return r[item]

    def __setup_styles(s):
        # 自定义TTK风格
        style = ttk.Style(s.master)
        arrow_layout = lambda dir: (
            [('Button.focus', {'children': [('Button.%sarrow' % dir, None)]})]
        )
        style.layout('L.TButton', arrow_layout('left'))
        style.layout('R.TButton', arrow_layout('right'))

    def __place_widgets(s):
        # 标头框架及其小部件
        Input_judgment_num = s.master.register(s.Input_judgment)  # 需要将函数包装一下，必要的
        hframe = ttk.Frame(s.G_Frame)
        gframe = ttk.Frame(s.G_Frame)
        bframe = ttk.Frame(s.G_Frame)
        hframe.pack(in_=s.G_Frame, side='top', pady=5, anchor='center')
        gframe.pack(in_=s.G_Frame, fill=tk.X, pady=5)
        bframe.pack(in_=s.G_Frame, side='bottom', pady=5)

        lbtn = ttk.Button(hframe, style='L.TButton', command=s._prev_month)
        lbtn.grid(in_=hframe, column=0, row=0, padx=12)
        rbtn = ttk.Button(hframe, style='R.TButton', command=s._next_month)
        rbtn.grid(in_=hframe, column=5, row=0, padx=12)

        s.CB_year = ttk.Combobox(hframe, width=5, values=[str(year) for year in
                                                          range(datetime.now().year, datetime.now().year - 11, -1)],
                                 validate='key', validatecommand=(Input_judgment_num, '%P'))
        s.CB_year.current(0)
        s.CB_year.grid(in_=hframe, column=1, row=0)
        s.CB_year.bind('<KeyPress>', lambda event: s._update(event, True))
        s.CB_year.bind("<<ComboboxSelected>>", s._update)
        tk.Label(hframe, text='年', justify='left').grid(in_=hframe, column=2, row=0, padx=(0, 5))

        s.CB_month = ttk.Combobox(hframe, width=3, values=['%02d' % month for month in range(1, 13)], state='readonly')
        s.CB_month.current(datetime.now().month - 1)
        s.CB_month.grid(in_=hframe, column=3, row=0)
        s.CB_month.bind("<<ComboboxSelected>>", s._update)
        tk.Label(hframe, text='月', justify='left').grid(in_=hframe, column=4, row=0)

        # 日历部件
        s._calendar = ttk.Treeview(gframe, show='', selectmode='none', height=7)
        s._calendar.pack(expand=1, fill='both', side='bottom', padx=5)

        ttk.Button(bframe, text="确 定", width=6, command=lambda: s._exit(True)).grid(row=0, column=0, sticky='ns',
                                                                                    padx=20)
        ttk.Button(bframe, text="取 消", width=6, command=s._exit).grid(row=0, column=1, sticky='ne', padx=20)

        tk.Frame(s.G_Frame, bg='#565656').place(x=0, y=0, relx=0, rely=0, relwidth=1, relheigh=2 / 200)
        tk.Frame(s.G_Frame, bg='#565656').place(x=0, y=0, relx=0, rely=198 / 200, relwidth=1, relheigh=2 / 200)
        tk.Frame(s.G_Frame, bg='#565656').place(x=0, y=0, relx=0, rely=0, relwidth=2 / 200, relheigh=1)
        tk.Frame(s.G_Frame, bg='#565656').place(x=0, y=0, relx=198 / 200, rely=0, relwidth=2 / 200, relheigh=1)

    def __config_calendar(s):
        # cols = s._cal.formatweekheader(3).split()
        cols = ['日', '一', '二', '三', '四', '五', '六']
        s._calendar['columns'] = cols
        s._calendar.tag_configure('header', background='grey90')
        s._calendar.insert('', 'end', values=cols, tag='header')
        # 调整其列宽
        font = tkFont.Font()
        maxwidth = max(font.measure(col) for col in cols)
        for col in cols:
            s._calendar.column(col, width=maxwidth, minwidth=maxwidth,
                               anchor='center')

    def __setup_selection(s, sel_bg, sel_fg):
        def __canvas_forget(evt):
            canvas.place_forget()
            s._selection = None

        s._font = tkFont.Font()
        s._canvas = canvas = tk.Canvas(s._calendar, background=sel_bg, borderwidth=0, highlightthickness=0)
        canvas.text = canvas.create_text(0, 0, fill=sel_fg, anchor='w')

        canvas.bind('<Button-1>', __canvas_forget)
        s._calendar.bind('<Configure>', __canvas_forget)
        s._calendar.bind('<Button-1>', s._pressed)

    def _build_calendar(s):
        year, month = s._date.year, s._date.month

        # update header text (Month, YEAR)
        header = s._cal.formatmonthname(year, month, 0)

        # 更新日历显示的日期
        cal = s._cal.monthdayscalendar(year, month)
        for indx, item in enumerate(s._items):
            week = cal[indx] if indx < len(cal) else []
            fmt_week = [('%02d' % day) if day else '' for day in week]
            s._calendar.item(item, values=fmt_week)

    def _show_select(s, text, bbox):
        """为新的选择配置画布。"""
        x, y, width, height = bbox

        textw = s._font.measure(text)

        canvas = s._canvas
        canvas.configure(width=width, height=height)
        canvas.coords(canvas.text, (width - textw) / 2, height / 2 - 1)
        canvas.itemconfigure(canvas.text, text=text)
        canvas.place(in_=s._calendar, x=x, y=y)

    def _pressed(s, evt=None, item=None, column=None, widget=None):
        """在日历的某个地方点击。"""
        if not item:
            x, y, widget = evt.x, evt.y, evt.widget
            item = widget.identify_row(y)
            column = widget.identify_column(x)

        if not column or not item in s._items:
            # 在工作日行中单击或仅在列外单击。
            return

        item_values = widget.item(item)['values']
        if not len(item_values):  # 这个月的行是空的。
            return

        text = item_values[int(column[1]) - 1]
        if not text:  # 日期为空
            return

        bbox = widget.bbox(item, column)
        if not bbox:  # 日历尚不可见
            s.master.after(20, lambda: s._pressed(item=item, column=column, widget=widget))
            return

        # 更新，然后显示选择
        text = '%02d' % text
        s._selection = (text, item, column)
        s._show_select(text, bbox)

    def _prev_month(s):
        """更新日历以显示前一个月。"""
        s._canvas.place_forget()
        s._selection = None

        s._date = s._date - timedelta(days=1)
        s._date = datetime(s._date.year, s._date.month, 1)
        s.CB_year.set(s._date.year)
        s.CB_month.set(s._date.month)
        s._update()

    def _next_month(s):
        """更新日历以显示下一个月。"""
        s._canvas.place_forget()
        s._selection = None

        year, month = s._date.year, s._date.month
        s._date = s._date + timedelta(
            days=calendar.monthrange(year, month)[1] + 1)
        s._date = datetime(s._date.year, s._date.month, 1)
        s.CB_year.set(s._date.year)
        s.CB_month.set(s._date.month)
        s._update()

    def _update(s, event=None, key=None):
        """刷新界面"""
        if key and event.keysym != 'Return': return
        year = int(s.CB_year.get())
        month = int(s.CB_month.get())
        if year == 0 or year > 9999: return
        s._canvas.place_forget()
        s._date = datetime(year, month, 1)
        s._build_calendar()  # 重建日历

        if year == datetime.now().year and month == datetime.now().month:
            day = datetime.now().day
            for _item, day_list in enumerate(s._cal.monthdayscalendar(year, month)):
                if day in day_list:
                    item = 'I00' + str(_item + 2)
                    column = '#' + str(day_list.index(day) + 1)
                    s.master.after(100, lambda: s._pressed(item=item, column=column, widget=s._calendar))

    def _exit(s, confirm=False):
        """退出窗口"""
        if not confirm: s._selection = None
        s.master.destroy()

    def _main_judge(s):
        """判断窗口是否在最顶层"""
        try:
            # s.master 为 TK 窗口
            # if not s.master.focus_displayof(): s._exit()
            # else: s.master.after(10, s._main_judge)

            # s.master 为 toplevel 窗口
            if s.master.focus_displayof() == None or 'toplevel' not in str(s.master.focus_displayof()):
                s._exit()
            else:
                s.master.after(10, s._main_judge)
        except:
            s.master.after(10, s._main_judge)

        # s.master.tk_focusFollowsMouse() # 焦点跟随鼠标

    def selection(s):
        """返回表示当前选定日期的日期时间。"""
        if not s._selection: return None

        year, month = s._date.year, s._date.month
        return str(datetime(year, month, int(s._selection[0])))[:10]

    def Input_judgment(s, content):
        """输入判断"""
        # 如果不加上==""的话，就会发现删不完。总会剩下一个数字
        if content.isdigit() or content == "":
            return True
        else:
            return False


if __name__ == '__main__':
    root = tk.Tk()

    width, height = root.winfo_reqwidth() + 50, 50  # 窗口大小
    x, y = (root.winfo_screenwidth() - width) / 2, (root.winfo_screenheight() - height) / 2
    root.geometry('%dx%d+%d+%d' % (width, height, x, y))  # 窗口位置居中

    date_str = tk.StringVar()
    date = ttk.Entry(root, textvariable=date_str)
    date.place(x=0, y=0, relx=5 / 20, rely=1 / 6, relwidth=14 / 20, relheigh=2 / 3)

    # Calendar((x, y), 'ur').selection() 获取日期，x,y为点坐标
    date_str_gain = lambda: [
        date_str.set(date)
        for date in [Calendar((x, y), 'ur').selection()]
        if date]
    tk.Button(root, text='日期:', command=date_str_gain).place(x=0, y=0, relx=1 / 20, rely=1 / 6, relwidth=4 / 20,
                                                             relheigh=2 / 3)
    root.mainloop()
