From 6aff4bb9ecadcf6c135e75958c8002a3c202d7df Mon Sep 17 00:00:00 2001
From: rustaceanrob <rob.netzke@gmail.com>
Date: Wed, 14 Jan 2026 11:47:49 +0000
Subject: [PATCH] Add `FilterType` enum

Enables futurue experimentation by adding new filter variants that can
be passed through the builder. Currently set to the only supported
filter, basic.
---
 src/builder.rs     |  8 +++++++-
 src/chain/chain.rs | 12 ++++++++----
 src/lib.rs         | 19 +++++++++++++++++++
 src/node.rs        |  2 ++
 4 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/src/builder.rs b/src/builder.rs
index ee894cf6..f1fab3f2 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -6,8 +6,8 @@ use bitcoin::Network;
 use super::{client::Client, node::Node};
 use crate::chain::ChainState;
 use crate::network::ConnectionType;
-use crate::Config;
 use crate::TrustedPeer;
+use crate::{Config, FilterType};
 
 const MIN_PEERS: u8 = 1;
 const MAX_PEERS: u8 = 15;
@@ -132,6 +132,12 @@ impl Builder {
         self
     }
 
+    /// Request a specific compact sketch type.
+    pub fn filter_type(mut self, filter_type: FilterType) -> Self {
+        self.config.filter_type = filter_type;
+        self
+    }
+
     /// Consume the node builder and receive a [`Node`] and [`Client`].
     pub fn build(mut self) -> (Node, Client) {
         Node::new(self.network, core::mem::take(&mut self.config))
diff --git a/src/chain/chain.rs b/src/chain/chain.rs
index c523e04a..7e1247b1 100644
--- a/src/chain/chain.rs
+++ b/src/chain/chain.rs
@@ -14,10 +14,9 @@ use super::{
     CFHeaderBatch, CFHeaderChanges, ChainState, Filter, FilterCheck, FilterHeaderRequest,
     FilterRequest, FilterRequestState, HeaderValidationExt, HeightMonitor, PeerId,
 };
-use crate::IndexedFilter;
 use crate::{chain::BlockHeaderChanges, messages::Event, Dialog, Info, Progress};
+use crate::{FilterType, IndexedFilter};
 
-const FILTER_BASIC: u8 = 0x00;
 const CF_HEADER_BATCH_SIZE: u32 = 1_999;
 const FILTER_BATCH_SIZE: u32 = 999;
 
@@ -28,6 +27,7 @@ pub(crate) struct Chain {
     network: Network,
     heights: Arc<Mutex<HeightMonitor>>,
     dialog: Arc<Dialog>,
+    filter_type: FilterType,
 }
 
 impl Chain {
@@ -37,6 +37,7 @@ impl Chain {
         dialog: Arc<Dialog>,
         height_monitor: Arc<Mutex<HeightMonitor>>,
         quorum_required: u8,
+        filter_type: FilterType,
     ) -> Self {
         let header_chain = match chain_state {
             ChainState::Snapshot(headers) => {
@@ -60,6 +61,7 @@ impl Chain {
             network,
             heights: height_monitor,
             dialog,
+            filter_type,
         }
     }
 
@@ -295,7 +297,7 @@ impl Chain {
             stop_hash,
         });
         GetCFHeaders {
-            filter_type: FILTER_BASIC,
+            filter_type: self.filter_type.into(),
             start_height: last_unchecked_cfheader,
             stop_hash,
         }
@@ -372,7 +374,7 @@ impl Chain {
             start_height: last_unchecked_filter,
         });
         GetCFilters {
-            filter_type: FILTER_BASIC,
+            filter_type: self.filter_type.into(),
             start_height: last_unchecked_filter,
             stop_hash,
         }
@@ -437,6 +439,7 @@ mod tests {
     use tokio::sync::Mutex;
 
     use crate::chain::ChainState;
+    use crate::FilterType;
     use crate::{
         chain::checkpoints::HeaderCheckpoint,
         messages::{Event, Info, Warning},
@@ -459,6 +462,7 @@ mod tests {
             Arc::new(Dialog::new(info_tx, warn_tx, event_tx)),
             height_monitor,
             peers,
+            FilterType::Basic,
         )
     }
 
diff --git a/src/lib.rs b/src/lib.rs
index ce205b8a..2e670f15 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -110,6 +110,23 @@ impl IndexedBlock {
     }
 }
 
+/// The type of filter to make a request for.
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord)]
+#[non_exhaustive]
+pub enum FilterType {
+    #[default]
+    /// A golomb coded compact sketch based on siphash. Contains all spendable script types.
+    Basic,
+}
+
+impl From<FilterType> for u8 {
+    fn from(value: FilterType) -> Self {
+        match value {
+            FilterType::Basic => 0x00,
+        }
+    }
+}
+
 /// A compact block filter with associated height.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IndexedFilter {
@@ -334,6 +351,7 @@ struct Config {
     chain_state: Option<ChainState>,
     connection_type: ConnectionType,
     peer_timeout_config: PeerTimeoutConfig,
+    filter_type: FilterType,
 }
 
 impl Default for Config {
@@ -345,6 +363,7 @@ impl Default for Config {
             chain_state: Default::default(),
             connection_type: Default::default(),
             peer_timeout_config: PeerTimeoutConfig::default(),
+            filter_type: FilterType::default(),
         }
     }
 }
diff --git a/src/node.rs b/src/node.rs
index 89286e76..62cef75c 100644
--- a/src/node.rs
+++ b/src/node.rs
@@ -74,6 +74,7 @@ impl Node {
             chain_state,
             connection_type,
             peer_timeout_config,
+            filter_type,
         } = config;
         // Set up a communication channel between the node and client
         let (info_tx, info_rx) = mpsc::channel::<Info>(32);
@@ -107,6 +108,7 @@ impl Node {
             Arc::clone(&dialog),
             height_monitor,
             required_peers,
+            filter_type,
         );
         (
             Self {