from tkinter import *
from tkinter import ttk
import sys
import subprocess

calendar = subprocess.check_output(["cal", "-m"])
calendar = calendar.decode("utf-8")
calendar = calendar.split("\n")
calendar = [x.split() for x in calendar]

today = subprocess.check_output(["date", "+\"%d\""])
today = today.decode("utf-8")[:-1]
today = today.strip("\"")

month_year = calendar[0]
calendar_fields = [calendar[1], calendar[2], calendar[3], calendar[4], calendar[5], calendar[6]]

root = Tk()
root.geometry("+0+0")
root.attributes("-type", "dialog")

frame = ttk.Frame(root)
frame.grid()

date_label = ttk.Label(frame, text=" ".join(month_year)).grid(row=0, columnspan=7)
prev_month_button = ttk.Button(frame, text="<", command=exit, width=1).grid(row=0, column=0)
next_month_button = ttk.Button(frame, text=">", command=exit, width=1).grid(row=0, column=6)

def get_agenda(date):
    date = "2022-12-" + date
    agenda = subprocess.check_output(["khal", "list", date, date])
    agenda = agenda.decode("utf-8")[:-1]
    agenda = agenda.split("\n")[1]
    return agenda


row_count = 1
column_count = 0
for r in calendar_fields:
    for c in r:
        if c == today:
            label = ttk.Label(frame, text=c, background="green").grid(row=row_count, column=column_count)
        else:
            label = ttk.Label(frame, text=c).grid(row=row_count, column=column_count)
        column_count += 1
    column_count = 0
    row_count += 1

agenda_label = ttk.Label(frame, text=get_agenda(today)).grid(row=row_count+1, columnspan=7)

def exit():
    sys.exit()

root.mainloop()