use chrono::{DateTime, Local, Utc};
use colored::Colorize;
use core::cmp::PartialEq;

pub trait IsStation {
  fn name(&self) -> &str;
  fn scheduled_arrival(&self) -> Option<&DateTime<Utc>>;
  fn real_arrival(&self) -> Option<&DateTime<Utc>>;
  fn ds100(&self) -> Option<&str>;

  fn to_fancy_string(&self) -> String {
    // travelynx literally sends this entire precise date in case of an
    // unknown time instead of, like, a null
    let epoch = "1970-01-01T00:00:00Z".parse::<DateTime<Local>>().unwrap();
    format!(
      "{} {} – {} ({})",
      self
        .real_arrival()
        .map(|t| if t.eq(&epoch) {
          "unknown ".to_owned()
        } else { // chrono's API for timezones is expressive, but reads like c++ …
          <DateTime<Local>>::from(*t).time().format("%T").to_string()
        })
        .unwrap_or("<format error>".to_string())
        .blue(),
      {
        let delay = match (self.real_arrival(), self.scheduled_arrival()) {
          (Some(a), Some(s)) => (a.time() - s.time()).num_minutes(),
          _ => 0
        };
        let text = format!("({:+})", delay);
        if delay > 0 {
          text.red()
        } else {
          text.green()
        }
      },
      self.ds100().unwrap_or("??").red(),
      self.name()
    )
  }
}