use super::{
    event::{Created, Event, Kind},
    Id,
};

#[derive(Clone, Debug, Eq, PartialEq, serde::Serialize)]
pub struct Channel {
    pub id: Id,
    pub name: String,
}

impl Channel {
    fn apply(state: Option<Self>, event: Event) -> Option<Self> {
        match (state, event.kind) {
            (None, Kind::Created(event)) => Some(event.into()),
            (Some(channel), Kind::Deleted(event)) if channel.id == event.channel => None,
            (state, event) => panic!("invalid channel event {event:#?} for state {state:#?}"),
        }
    }
}

impl FromIterator<Event> for Option<Channel> {
    fn from_iter<I: IntoIterator<Item = Event>>(events: I) -> Self {
        events.into_iter().fold(None, Channel::apply)
    }
}

impl From<&Created> for Channel {
    fn from(event: &Created) -> Self {
        event.channel.clone()
    }
}

impl From<Created> for Channel {
    fn from(event: Created) -> Self {
        event.channel
    }
}