#!/bin/env python3
import datetime
from tkinter import Tk, CENTER, Label, font
import click
import typing as t

DELTA_SECONDS = "+%Ss"
DELTA_MINUTES = "+%Mm"
DELTA_HOURS = "+%Hh"
TIME_TODAY = "%H:%M"
DATETIME_FORMAT = [
    "%Y-%m-%d",
    "%Y-%m-%dT%H:%M:%S",
    "%Y-%m-%d %H:%M:%S",
    "%Y-%m-%d %H:%M",
    TIME_TODAY,
    DELTA_HOURS,
    DELTA_MINUTES,
    DELTA_SECONDS,
]
FONT = "Liberation Sans"


class DateTime(click.DateTime):
    def _try_to_convert_date(self, value: t.Any, format: str) -> t.Optional[datetime]:
        try:
            if value[0] == "+":
                if format == DELTA_SECONDS and value[-1] == "s":
                    return datetime.datetime.now() + datetime.timedelta(
                        seconds=int(value[1:-1])
                    )
                if format == DELTA_MINUTES and value[-1] == "m":
                    return datetime.datetime.now() + datetime.timedelta(
                        minutes=int(value[1:-1])
                    )
                if format == DELTA_HOURS and value[-1] == "h":
                    return datetime.datetime.now() + datetime.timedelta(
                        hours=int(value[1:-1])
                    )
            if format == TIME_TODAY:
                return datetime.datetime.combine(
                    datetime.datetime.now().date(),
                    datetime.datetime.strptime(value, format).time(),
                )
            return datetime.datetime.strptime(value, format)
        except ValueError:
            return None


class Timer:
    def __init__(self, end_date):
        self.end_date = end_date
        self.update()

    def update(self):
        self.delta = self.end_date - datetime.datetime.now()

    def calc_delta(self):
        days, remainder = divmod(self.delta.total_seconds(), 60 * 60 * 24)
        hours, remainder = divmod(remainder, 3600)
        minutes, seconds = divmod(remainder, 60)
        return int(days), int(hours), int(minutes), int(seconds)

    @classmethod
    def get_format(cls, days, hours, minutes, seconds):
        if days == 0:
            if hours == 0:
                if minutes == 0:
                    return "{seconds:02d}"
                return "{minutes:02d}:{seconds:02d}"
            return "{hours:02d}:{minutes:02d}:{seconds:02d}"
        return "{days:02d}:{hours:02d}:{minutes:02d}:{seconds:02d}"

    def __str__(self):
        days, hours, minutes, seconds = self.calc_delta()
        return self.get_format(days, hours, minutes, seconds).format(
            days=days, hours=hours, minutes=minutes, seconds=seconds
        )


current_size = {
    "format": Timer.get_format(9, 9, 9, 9),
    "height": 800,
    "width": 800,
}


def start_app(end_date):
    timer = Timer(end_date)
    root = Tk()
    root.geometry("300x100+200+200")
    root.configure(background="#000")
    font_instance = font.Font(font=(FONT, -100))
    timer_label = Label(root, text="", font=font_instance, fg="#fff", bg="#000")
    timer_label.pack()
    timer_label.place(relx=0.5, rely=0.5, anchor=CENTER)
    fixed_font_instance = font.Font(font=(FONT, -100))

    def resize(_):
        global current_size
        try:
            next_size = {
                "format": timer.get_format(
                    *(99 if x else 0 for x in timer.calc_delta())
                ),
                "height": root.winfo_height(),
                "width": root.winfo_width(),
            }
            if current_size != next_size:
                next_font_height = int(
                    min(
                        root.winfo_height(),
                        (
                            root.winfo_width()
                            / fixed_font_instance.measure(next_size["format"])
                        )
                        * 250,
                    )
                )
                font_instance.config(size=next_font_height)
                timer_label.configure(font=font_instance)
                current_size = next_size
        except ZeroDivisionError:
            pass

    def update():
        timer.update()
        if timer.delta.total_seconds() <= 0:
            timer_label.configure(text="Now")
            timer_label.config(fg="red")
        else:
            timer_label.configure(text=str(timer))
        root.after(1000 - datetime.datetime.now().microsecond // 1000, update)

    root.bind("<Configure>", resize)
    root.bind("<Escape>", lambda x: root.destroy())
    root.after(1, update)
    root.mainloop()


@click.command()
@click.argument("end_date", type=DateTime(formats=DATETIME_FORMAT))
def main(end_date):
    start_app(end_date)


if __name__ == "__main__":
    main()