use super::{
    Body, Id,
    event::{Event, Sent},
};
use crate::{conversation, event::Instant, user};
use serde_with::with_prefix;

#[derive(Clone, Debug, Eq, PartialEq, serde::Serialize)]
pub struct Message {
    #[serde(flatten)]
    pub sent: Instant,
    pub conversation: conversation::Id,
    pub sender: user::Id,
    pub id: Id,
    pub body: Body,
    #[serde(
        flatten,
        with = "prefix_deleted",
        skip_serializing_if = "Option::is_none"
    )]
    pub deleted: Option<Instant>,
}

with_prefix!(prefix_deleted "deleted_");

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

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

impl From<&Sent> for Message {
    fn from(event: &Sent) -> Self {
        event.message.clone()
    }
}

impl From<Sent> for Message {
    fn from(event: Sent) -> Self {
        event.message
    }
}