#!/usr/bin/env python3

import requests
import os
from bs4 import BeautifulSoup
from datetime import datetime, timedelta
import locale
import pytz
from icalendar import Calendar, Event




def zic2ics():
    locale.setlocale(locale.LC_TIME,'it_IT.UTF-8')
    os.makedirs('history', exist_ok=True)

    cal = Calendar()
    cal.add('prodid', '-//Agenda di zic.it//')
    cal.add('version', '2.0')

    page = requests.get("https://zic.it/agenda/")
    soup = BeautifulSoup(page.content, "html.parser")

    agenda = soup.find("div", class_="entry-content clearfix")
    entries = agenda.find_all("p", style=None)

    for entry in entries:
        try:
            lnk = entry.find('a', href=True)['href']

            spe = entry.get_text(strip=True, separator='\n').splitlines()
            tit = spe[0].strip()
            dat = datetime.strptime(spe[2], "%A %d %B %Y - %H:%M").replace(tzinfo=pytz.timezone('Europe/Rome'))
            
            det = spe[3][2:-2].split(";")
            dov = det[0].strip()
            chi = det[1].strip() if 1 < len(det) else ""
            # print(" ~ ".join([tit, str(dat), dov, chi]))

            uid = "|".join([dat.strftime("%Y%m%d"), tit, dov])

            event = Event()
            event.add('summary', tit)
            event.add('dtstart', dat)
            event.add('description', chi)
            event.add('location', dov)
            event.add('url', lnk)
            event.add('uid', uid)
            cal.add_component(event)
    
        except:
            pass
    
    ical = cal.to_ical()

    try:
        with open('zic.ics', 'rb') as f:
            ical_last = f.read()
    except:
        ical_last = ""

    if ical != ical_last:

        try:
            with open('zic_all.ics', 'rb') as f:
                cal_all = Calendar.from_ical(f.read())
        except:
            cal_all = Calendar()
        ical_all = icalmerge(cal_all, cal).to_ical()

        with open('zic.ics', 'wb') as f:
            f.write(ical)

        with open('zic_all.ics', 'wb') as f:
            f.write(ical_all)

        with open(os.path.join('history','zic_%s.ics' % datetime.now().strftime("%Y%m%d%H%M%S")), 'wb') as f:
            f.write(ical)

        with open(os.path.join('history','zic_%s.html' % datetime.now().strftime("%Y%m%d%H%M%S")), 'wb') as f:
            f.write(page.content)






def icalmerge(calold, calnew, delete = False, tolerance = 15):

    cal = Calendar()
    cal.add('prodid', calnew.get('prodid').to_ical().decode('utf-8'))
    cal.add('version', calnew.get('version').to_ical().decode('utf-8'))


    #Add a computed UID if missing
    for e in calold.walk('VEVENT'):
        if e.get('UID') is None:
            uid = "|".join([e.decoded('dtstart').strftime("%Y%m%d"), e.get('Summary').to_ical().decode('utf-8'), e.get('Location').to_ical().decode('utf-8')])
            e.add('uid', uid)

    for e in calnew.walk('VEVENT'):
        if e.get('UID') is None:
            uid = "|".join([e.decoded('dtstart').strftime("%Y%m%d"), e.get('Summary').to_ical().decode('utf-8'), e.get('Location').to_ical().decode('utf-8')])
            e.add('uid', uid)

    calold_uids = [e.get('UID').to_ical().decode('utf-8') for e in calold.walk('VEVENT')]
    calnew_uids = [e.get('UID').to_ical().decode('utf-8') for e in calnew.walk('VEVENT')]

    imported_uids = []
    for e in calold.walk('VEVENT'):
        uid = e.get('UID').to_ical().decode('utf-8')

        if uid not in calnew_uids:
            if e.decoded('dtstart') < datetime.now(pytz.UTC) + timedelta(minutes = tolerance):
                print("Past      \"%s\"" % uid)
                cal.add_component(e)
            else:
                if delete:
                    print("Deleted   \"%s\"" % uid)
                else:
                    print("Cancelled \"%s\"" % uid)
                    e.add('status', 'CANCELLED')
                    cal.add_component(e)

    for e in calnew.walk('VEVENT'):
        uid = e.get('UID').to_ical().decode('utf-8')
        if uid not in calold_uids:
            print("Added     \"%s\"" % uid)
            cal.add_component(e)
        else:
            # print("Updated   \"%s\"" % uid)
            cal.add_component(e)

    return(cal)




        
if __name__ == "__main__":
    os.chdir(os.path.dirname(__file__))
    zic2ics()