Files
damus/damus/Util/EventCache.swift
2023-03-05 14:50:12 -05:00

93 lines
2.1 KiB
Swift

//
// EventCache.swift
// damus
//
// Created by William Casarin on 2023-02-21.
//
import Combine
import Foundation
import UIKit
class EventCache {
private var events: [String: NostrEvent] = [:]
private var replies = ReplyMap()
private var cancellable: AnyCancellable?
//private var thread_latest: [String: Int64]
init() {
cancellable = NotificationCenter.default.publisher(
for: UIApplication.didReceiveMemoryWarningNotification
).sink { [weak self] _ in
self?.prune()
}
}
func parent_events(event: NostrEvent) -> [NostrEvent] {
var parents: [NostrEvent] = []
var ev = event
while true {
guard let direct_reply = ev.direct_replies(nil).first else {
break
}
guard let next_ev = lookup(direct_reply.ref_id), next_ev != ev else {
break
}
parents.append(next_ev)
ev = next_ev
}
return parents.reversed()
}
func add_replies(ev: NostrEvent) {
for reply in ev.direct_replies(nil) {
replies.add(id: reply.ref_id, reply_id: ev.id)
}
}
func child_events(event: NostrEvent) -> [NostrEvent] {
guard let xs = replies.lookup(event.id) else {
return []
}
let evs: [NostrEvent] = xs.reduce(into: [], { evs, evid in
guard let ev = self.lookup(evid) else {
return
}
evs.append(ev)
}).sorted(by: { $0.created_at < $1.created_at })
return evs
}
func upsert(_ ev: NostrEvent) -> NostrEvent {
if let found = lookup(ev.id) {
return found
}
insert(ev)
return ev
}
func lookup(_ evid: String) -> NostrEvent? {
return events[evid]
}
func insert(_ ev: NostrEvent) {
guard events[ev.id] == nil else {
return
}
events[ev.id] = ev
}
private func prune() {
events = [:]
replies.replies = [:]
}
}