diff --git a/src/patch/patch.rs b/src/patch/patch.rs
index 52dd7d2..4a43477 100644
--- a/src/patch/patch.rs
+++ b/src/patch/patch.rs
@@ -18,6 +18,7 @@ use crate::common::serverstate::{RecvServerPacket, SendServerPacket, ServerState
 pub enum PatchError {
     NetworkError(NetworkError),
     IOError(std::io::Error),
+    NoSuchClient(ClientId),
 }
 
 impl From<NetworkError> for PatchError {
@@ -135,11 +136,11 @@ impl SendServerPacket for SendPatchPacket {
     }
 }
 
-
 pub struct PatchServerState {
     patch_file_tree: PatchFileTree,
     patch_file_lookup: HashMap<u32, PatchFile>,
     patch_file_info: Vec<FileInfoReply>,
+    client_file_info: HashMap<ClientId, Vec<FileInfoReply>>,
     patch_motd: String,
 }
 
@@ -149,6 +150,7 @@ impl PatchServerState {
             patch_file_tree,
             patch_file_lookup,
             patch_file_info: Vec::new(),
+            client_file_info: HashMap::new(),
             patch_motd,
         }
     }
@@ -160,10 +162,11 @@ impl ServerState for PatchServerState {
     type RecvPacket = RecvPatchPacket;
     type PacketError = PatchError;
 
-    async fn on_connect(&mut self, _id: ClientId) -> Result<Vec<OnConnect<Self::SendPacket>>, PatchError> {
+    async fn on_connect(&mut self, id: ClientId) -> Result<Vec<OnConnect<Self::SendPacket>>, PatchError> {
         let mut rng = rand::thread_rng();
         let key_in: u32 = rng.gen();
         let key_out: u32 = rng.gen();
+        self.client_file_info.insert(id, Vec::new());
 
         Ok(vec![OnConnect::Packet(SendPatchPacket::PatchWelcome(PatchWelcome::new(key_out, key_in))),
              OnConnect::Cipher((Box::new(PSOPCCipher::new(key_in)), Box::new(PSOPCCipher::new(key_out))))
@@ -183,26 +186,39 @@ impl ServerState for PatchServerState {
                 Box::new(p.into_iter().map(move |pkt| (id, pkt)))
             },
             RecvPatchPacket::FileInfoReply(pkt) => {
-                self.patch_file_info.push(pkt.clone());
+                self.client_file_info.get_mut(&id).ok_or(PatchError::NoSuchClient(id))?.push(pkt.clone()); // it should be impossible to error here under normal conditions?
+                // self.patch_file_info.push(pkt.clone());
+                // println!("PatchServerState.patch_file_info: {:?}", self.patch_file_info);
                 Box::new(None.into_iter().map(move |pkt| (id, pkt)))
             },
             RecvPatchPacket::FileInfoListEnd(_pkt) => {
-                let need_update = self.patch_file_info.iter()
-                    .filter(|file_info| does_file_need_updating(file_info, &self.patch_file_lookup))
-                    .collect::<Vec<_>>();
-
-                let total_size = need_update.iter().fold(0, |a, file_info| a + file_info.size);
+                // let need_update = self.patch_file_info.iter()
+                //     .filter(|file_info| does_file_need_updating(file_info, &self.patch_file_lookup))
+                //     .collect::<Vec<_>>();
+                println!("patch server hashmap: {:?}", self.patch_file_lookup);
+                let need_update = self.client_file_info.get(&id)
+                    .ok_or(PatchError::NoSuchClient(id))?
+                    .iter()
+                    .filter(|client_file_info| does_file_need_updating(client_file_info, &self.patch_file_lookup))
+                    .collect::<Vec<_>>(); // collecting list of `client_file_info`s. need to map these to the patch_files and collect those
+                println!("ClientId({}) needs these files to be updated: {:?}", id, need_update);
+                // we have the file ids that need to be updated
+                let total_size = need_update.iter()
+                                            .filter_map(|client_file| self.patch_file_lookup.get(&client_file.id)) // TODO: dont unwrap?
+                                            .fold(0, |a, file_info| a + file_info.size);
                 let total_files = need_update.len() as u32;
-
+                println!("client {} needs {} bytes of updates across {} files", id, total_size, total_files);
                 let p = vec![SendPatchPacket::FilesToPatchMetadata(FilesToPatchMetadata::new(total_size, total_files)),
                              SendPatchPacket::PatchStartList(PatchStartList {})
                 ];
-                Box::new(p.into_iter().chain(SendFileIterator::new(self)).map(move |pkt| (id, pkt)))
+                println!("p: {:?}", p);
+                Box::new(p.into_iter().chain(SendFileIterator::new(self, need_update)).map(move |pkt| (id, pkt)))
             }
         })
     }
 
-    async fn on_disconnect(&mut self, _id: ClientId) -> Result<Vec<(ClientId, SendPatchPacket)>, PatchError> {
+    async fn on_disconnect(&mut self, id: ClientId) -> Result<Vec<(ClientId, SendPatchPacket)>, PatchError> {
+        self.client_file_info.remove(&id);
         Ok(Vec::new())
     }
 }
@@ -279,9 +295,10 @@ fn get_checksum_and_size(path: &Path) -> Result<(u32, u32), PatchError> {
     Ok((crc.sum32(), size as u32))
 }
 
-fn does_file_need_updating(file_info: &FileInfoReply, patch_file_lookup: &HashMap<u32, PatchFile>) -> bool {
-    let patch_file = patch_file_lookup.get(&file_info.id).unwrap();
-    patch_file.checksum != file_info.checksum || patch_file.size != file_info.size
+fn does_file_need_updating(client_file_info: &FileInfoReply, patch_file_lookup: &HashMap<u32, PatchFile>) -> bool {
+    let patch_file = patch_file_lookup.get(&client_file_info.id).unwrap();
+    println!("checking if client_file {:?} and patch_file {:?} need to be updated", client_file_info, patch_file);
+    patch_file.checksum != client_file_info.checksum || patch_file.size != client_file_info.size
 }
 
 
@@ -294,9 +311,13 @@ struct SendFileIterator {
 }
 
 impl SendFileIterator {
-    fn new(state: &PatchServerState) -> SendFileIterator {
-        let file_ids_to_update = state.patch_file_info.iter()
-            .filter(|file_info| does_file_need_updating(file_info, &state.patch_file_lookup))
+    fn new(state: &PatchServerState, client_file_info: Vec<&FileInfoReply>) -> SendFileIterator {
+        // let file_ids_to_update = state.patch_file_info.iter()
+        //     .filter(|file_info| does_file_need_updating(file_info, &state.patch_file_lookup))
+        //     .map(|k| k.id)
+        //     .collect::<HashSet<_>>();
+
+        let file_ids_to_update = client_file_info.iter()
             .map(|k| k.id)
             .collect::<HashSet<_>>();