#![allow(unused_variables)]

#[derive(Debug)]
struct CubeSat {
  id: u64,
}

#[derive(Debug)]
struct Mailbox {
  messages: Vec<Message>,
}

#[derive(Debug)]
struct Message {
    to: u64,
    content: String,
}

struct GroundStation {}

impl Mailbox {
    fn post(&mut self, msg: Message) {
        self.messages.push(msg);
    }

    fn deliver(&mut self, recipient: &CubeSat) -> Option<Message> {
        for i in 0..self.messages.len() {
            if self.messages[i].to == recipient.id {
                let msg = self.messages.remove(i);
                return Some(msg);
            }
        }

        None
    }
}

impl GroundStation {
    fn connect(&self, sat_id: u64) -> CubeSat {
        CubeSat {
            id: sat_id, 
        }
    }

    fn send(&self, mailbox: &mut Mailbox, msg: Message) {
        mailbox.post(msg);
    }
}

impl CubeSat {
    fn recv(&self, mailbox: &mut Mailbox) -> Option<Message> {
        mailbox.deliver(&self)
    }
}

fn fetch_sat_ids() -> Vec<u64> {
  vec![1,2,3]
}


fn main() {
  let mut mail = Mailbox { messages: vec![] };

  let base = GroundStation {};

  let sat_ids = fetch_sat_ids();

  for sat_id in sat_ids {
    let sat = base.connect(sat_id);
    let msg = Message { to: sat_id, content: String::from("hello") };
    base.send(&mut mail, msg);
  }

  let sat_ids = fetch_sat_ids();

  for sat_id in sat_ids {
    let sat = base.connect(sat_id);
    
    let msg = sat.recv(&mut mail);
    println!("{:?}: {:?}", sat, msg);
  }
}