use serde_with::with_prefix;

use super::{
    Id,
    event::{Created, Event},
};
use crate::{event::Instant, name::Name};

#[derive(Clone, Debug, Eq, PartialEq, serde::Serialize)]
pub struct Conversation {
    #[serde(flatten)]
    pub created: Instant,
    pub id: Id,
    pub name: Name,
    #[serde(
        flatten,
        with = "prefix_deleted",
        skip_serializing_if = "Option::is_none"
    )]
    pub deleted: Option<Instant>,
}

with_prefix!(prefix_deleted "deleted_");

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

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

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

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