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use itertools::Itertools as _;
use super::{
event::{Deleted, Event, Sent},
Id, Message,
};
use crate::event::{Instant, Sequence};
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct History {
pub message: Message,
pub deleted: Option<Instant>,
}
// State interface
impl History {
pub fn id(&self) -> &Id {
&self.message.id
}
// Snapshot of this message as it was when sent. (Note to the future: it's okay
// if this returns a redacted or modified version of the message. If we
// implement message editing by redacting the original body, then this should
// return the edited message, not the original, even if that's not how it was
// "as sent.")
pub fn as_sent(&self) -> Message {
self.message.clone()
}
pub fn as_of(&self, resume_point: Sequence) -> Option<Message> {
self.events()
.filter(Sequence::up_to(resume_point))
.collect()
}
// Snapshot of this message as of all events recorded in this history.
pub fn as_snapshot(&self) -> Option<Message> {
self.events().collect()
}
}
// Events interface
impl History {
fn sent(&self) -> Event {
Sent {
message: self.message.clone(),
}
.into()
}
fn deleted(&self) -> Option<Event> {
self.deleted.map(|instant| {
Deleted {
instant,
id: self.message.id.clone(),
}
.into()
})
}
pub fn events(&self) -> impl Iterator<Item = Event> {
[self.sent()]
.into_iter()
.merge_by(self.deleted(), Sequence::merge)
}
}
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