From 6684449f275d09fc3d571d39e3ebd8b39fa965fb Mon Sep 17 00:00:00 2001
From: Jade Ellis <jade@ellis.link>
Date: Wed, 23 Apr 2025 21:28:46 +0100
Subject: [PATCH] WIP

---
 src/service/rooms/read_receipt/mod.rs | 52 ++++++++++++++++++++-------
 1 file changed, 39 insertions(+), 13 deletions(-)

diff --git a/src/service/rooms/read_receipt/mod.rs b/src/service/rooms/read_receipt/mod.rs
index 69e859c4..01321571 100644
--- a/src/service/rooms/read_receipt/mod.rs
+++ b/src/service/rooms/read_receipt/mod.rs
@@ -1,6 +1,6 @@
 mod data;
 
-use std::{collections::BTreeMap, sync::Arc};
+use std::{collections::{BTreeMap, HashMap}, sync::Arc};
 
 use conduwuit::{
 	Result, debug, err,
@@ -9,12 +9,9 @@ use conduwuit::{
 };
 use futures::{Stream, TryFutureExt, try_join};
 use ruma::{
-	OwnedEventId, OwnedUserId, RoomId, UserId,
 	events::{
-		AnySyncEphemeralRoomEvent, SyncEphemeralRoomEvent,
-		receipt::{ReceiptEvent, ReceiptEventContent, Receipts},
-	},
-	serde::Raw,
+		receipt::{ReceiptEvent, ReceiptEventContent, ReceiptType, Receipts}, AnySyncEphemeralRoomEvent, SyncEphemeralRoomEvent
+	}, serde::Raw, OwnedEventId, OwnedUserId, RoomId, UserId
 };
 
 use self::data::{Data, ReceiptItem};
@@ -47,19 +44,48 @@ impl crate::Service for Service {
 }
 
 impl Service {
-	/// Replaces the previous read receipt.
+	/// Updates the public read receipt (`m.read`) based on the incoming event.
+	/// If the event referenced by the new public receipt is newer than the current
+	/// private read marker (`m.read.private`), the private marker is also updated
+	/// to match the public receipt's position.
 	pub async fn readreceipt_update(
 		&self,
 		user_id: &UserId,
 		room_id: &RoomId,
 		event: &ReceiptEvent,
 	) {
-		self.db.readreceipt_update(user_id, room_id, event).await;
-		self.services
-			.sending
-			.flush_room(room_id)
-			.await
-			.expect("room flush failed");
+		debug!(target: "readreceipt", %room_id, %user_id, "Updating read receipt in database.");
+
+		// 2. Find the maximum PDU count for the m.read event(s) referenced in the new receipt
+		let mut max_new_public_pdu_count: Option<PduCount> = None;
+		for (event_id, receipts) in event.content.0.iter() {
+			// Check if this event_id has an m.read receipt for the target user
+			if let Some(user_receipts) = receipts.get(&ReceiptType::Read) {
+				if user_receipts.contains_key(user_id) {
+					// Try to get the PDU count (timeline position) for this event_id
+					match self.services.timeline.get_pdu_count(event_id).await {
+						Ok(count) => {
+							// Update the maximum count found so far
+							let current_max = max_new_public_pdu_count.unwrap_or(PduCount::Normal(0));
+							max_new_public_pdu_count = Some(current_max.max(count));
+							debug!(target: "readreceipt", %room_id, %user_id, %event_id, count, "Found PDU count for new public receipt event.");
+						}
+						Err(e) => {
+							warn!(
+								target: "readreceipt", %room_id, %user_id, %event_id,
+								"Failed to get PDU count for event ID from new public read receipt: {}",
+								e
+							);
+						}
+					}
+				}
+			}
+		}
+
+		// Flush the sending queue for the room to notify clients
+		if let Err(e) = self.services.sending.flush_room(room_id).await {
+			warn!(target: "readreceipt", %room_id, %user_id, "Failed to flush room after read receipt update: {}", e);
+		}
 	}
 
 	/// Gets the latest private read receipt from the user in the room