use icalendar;
use icalendar::{Component, DatePerhapsTime, CalendarDateTime, CalendarComponent};
use chrono::NaiveDate;
use crate::EventsCollection;
use std::fs;

fn cdt_as_date(cdt: &CalendarDateTime) -> NaiveDate {
    match cdt {
        CalendarDateTime::Floating(ndt) => ndt.date(),
        CalendarDateTime::Utc(ud) => ud.naive_local().date(),
        CalendarDateTime::WithTimezone{date_time, tzid: _} => date_time.date(),
    }
}

fn as_date(cal_date: &DatePerhapsTime) -> NaiveDate {
    match cal_date {
        DatePerhapsTime::DateTime(cdt) => cdt_as_date(cdt),
        DatePerhapsTime::Date(nd) => nd.clone()
    }
}

fn create_event(events: &mut EventsCollection, event: &icalendar::Event) {
    events.create(as_date(&event.get_start().unwrap()), as_date(&event.get_end().unwrap()).pred_opt().unwrap(), event.get_summary().unwrap());
}

pub fn load_calendar(calendar_path: &std::path::Path, events: &mut EventsCollection) {
    let mut calendar = icalendar::Calendar::new();
    let contents = fs::read_to_string(calendar_path)
        .expect("Could not read the calendar");
    let res = icalendar::parser::read_calendar(&contents);
    match res {
        Ok(parsed_calendar) => { calendar.extend(parsed_calendar.components); }
        Err(e) => println!("{}", e)
    }

    for cc in calendar.iter() {
        match cc {
            CalendarComponent::Event(event) => create_event(events, event),
            _ => (),
        }
    }

    events.sort();
}