From c004c8593cdbeef9899f04d9a8e090f2ea1747a2 Mon Sep 17 00:00:00 2001
From: Matthew <ramsden@hey.com>
Date: Tue, 7 Jan 2025 18:26:58 -0600
Subject: [PATCH] feat: add get_fee_estimates to EsploraClient

---
 bdk-ffi/src/bdk.udl    | 23 +++++++++++++++++++++++
 bdk-ffi/src/esplora.rs |  6 +++++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/bdk-ffi/src/bdk.udl b/bdk-ffi/src/bdk.udl
index e90e27dc..747b0868 100644
--- a/bdk-ffi/src/bdk.udl
+++ b/bdk-ffi/src/bdk.udl
@@ -1031,23 +1031,46 @@ interface Descriptor {
 // bdk_esplora crate
 // ------------------------------------------------------------------------
 
+/// Wrapper around an esplora_client::BlockingClient which includes an internal in-memory transaction
+/// cache to avoid re-fetching already downloaded transactions.
 interface EsploraClient {
+  /// Creates a new bdk client from a esplora_client::BlockingClient
   constructor(string url);
 
+  /// Scan keychain scripts for transactions against Esplora, returning an update that can be
+  /// applied to the receiving structures.
+  ///
+  /// `request` provides the data required to perform a script-pubkey-based full scan
+  /// (see [`FullScanRequest`]). The full scan for each keychain (`K`) stops after a gap of
+  /// `stop_gap` script pubkeys with no associated transactions. `parallel_requests` specifies
+  /// the maximum number of HTTP requests to make in parallel.
   [Throws=EsploraError]
   Update full_scan(FullScanRequest request, u64 stop_gap, u64 parallel_requests);
 
+  /// Sync a set of scripts, txids, and/or outpoints against Esplora.
+  ///
+  /// `request` provides the data required to perform a script-pubkey-based sync (see
+  /// [`SyncRequest`]). `parallel_requests` specifies the maximum number of HTTP requests to make
+  /// in parallel.
   [Throws=EsploraError]
   Update sync(SyncRequest request, u64 parallel_requests);
 
+  /// Broadcast a [`Transaction`] to Esplora.
   [Throws=EsploraError]
   void broadcast([ByRef] Transaction transaction);
 
+  /// Get a [`Transaction`] option given its [`Txid`].
   [Throws=EsploraError]
   Transaction? get_tx(string txid);
 
+  /// Get the height of the current blockchain tip.
   [Throws=EsploraError]
   u32 get_height();
+
+  /// Get a map where the key is the confirmation target (in number of
+  /// blocks) and the value is the estimated feerate (in sat/vB).
+  [Throws=EsploraError]
+  record<u16, f64> get_fee_estimates();
 };
 
 // ------------------------------------------------------------------------
diff --git a/bdk-ffi/src/esplora.rs b/bdk-ffi/src/esplora.rs
index 52338979..808d96ae 100644
--- a/bdk-ffi/src/esplora.rs
+++ b/bdk-ffi/src/esplora.rs
@@ -14,7 +14,7 @@ use bdk_wallet::chain::spk_client::SyncResponse as BdkSyncResponse;
 use bdk_wallet::KeychainKind;
 use bdk_wallet::Update as BdkUpdate;
 
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, HashMap};
 use std::str::FromStr;
 use std::sync::Arc;
 
@@ -93,4 +93,8 @@ impl EsploraClient {
     pub fn get_height(&self) -> Result<u32, EsploraError> {
         self.0.get_height().map_err(EsploraError::from)
     }
+
+    pub fn get_fee_estimates(&self) -> Result<HashMap<u16, f64>, EsploraError> {
+        self.0.get_fee_estimates().map_err(EsploraError::from)
+    }
 }