4 files changed, 67 insertions, 3 deletions
diff --git a/libs/nak_ffi/Cargo.lock b/libs/nak_ffi/Cargo.lock
index af0ac00..83d19cc 100644
--- a/libs/nak_ffi/Cargo.lock
+++ b/libs/nak_ffi/Cargo.lock
@@ -1129,7 +1129,7 @@ dependencies = [
 [[package]]
 name = "nak_rust"
 version = "4.4.1"
-source = "git+https://github.com/SulfurNitride/NaK.git?branch=main#ceea41b64e6cafb8375978d7982e2c46fe826047"
+source = "git+https://github.com/SulfurNitride/NaK.git?branch=main#41915b5a095da6bc5b4960eac2c9e55771caa7c4"
 dependencies = [
  "chrono",
  "rand",
diff --git a/libs/nak_ffi/Cargo.toml b/libs/nak_ffi/Cargo.toml
index 000297c..fc667e0 100644
--- a/libs/nak_ffi/Cargo.toml
+++ b/libs/nak_ffi/Cargo.toml
@@ -6,5 +6,5 @@ edition = "2021"
 [lib]
 crate-type = ["cdylib"]
 
-[dependencies]
-nak_rust = { git = "https://github.com/SulfurNitride/NaK.git", branch = "main", default-features = false, features = ["installer"] }
+[dependencies]
+nak_rust = { git = "https://github.com/SulfurNitride/NaK.git", branch = "main", default-features = false, features = ["installer"] }
diff --git a/libs/nak_ffi/include/nak_ffi.h b/libs/nak_ffi/include/nak_ffi.h
index c6010d4..df4d47b 100644
--- a/libs/nak_ffi/include/nak_ffi.h
+++ b/libs/nak_ffi/include/nak_ffi.h
@@ -194,6 +194,18 @@ char *nak_apply_wine_registry_settings(
     uint32_t app_id
 );
 
+/** Apply a game's registry entry with a custom install path.
+ *  Looks up game_name in KNOWN_GAMES and writes registry pointing to install_path.
+ *  Returns NULL on success, or an error message (free with nak_string_free). */
+char *nak_apply_registry_for_game_path(
+    const char *prefix_path,
+    const char *proton_name,
+    const char *proton_path,
+    const char *game_name,
+    const char *install_path,
+    NakLogCallback log_cb
+);
+
 /* ========================================================================
  * Tier 7: Prefix Symlinks
  * ======================================================================== */
diff --git a/libs/nak_ffi/src/lib.rs b/libs/nak_ffi/src/lib.rs
index 0e7b4f3..2e19af7 100644
--- a/libs/nak_ffi/src/lib.rs
+++ b/libs/nak_ffi/src/lib.rs
@@ -659,6 +659,58 @@ pub unsafe extern "C" fn nak_apply_wine_registry_settings(
     }
 }
 
+/// Apply a game's registry entry with a custom install path.
+///
+/// Looks up the game by name in KNOWN_GAMES, writes the registry entry
+/// pointing to `install_path`. Returns null on success, or an error message.
+#[no_mangle]
+pub unsafe extern "C" fn nak_apply_registry_for_game_path(
+    prefix_path: *const c_char,
+    proton_name: *const c_char,
+    proton_path: *const c_char,
+    game_name: *const c_char,
+    install_path: *const c_char,
+    log_cb: NakLogCallback,
+) -> *mut c_char {
+    let prefix = unsafe { from_cstr(prefix_path) };
+    let _proton_name = unsafe { from_cstr(proton_name) };
+    let proton_path_str = unsafe { from_cstr(proton_path) };
+    let game = unsafe { from_cstr(game_name) };
+    let install = unsafe { from_cstr(install_path) };
+
+    let protons = nak_rust::steam::find_steam_protons();
+    let proton = match protons
+        .iter()
+        .find(|p| p.path.to_string_lossy() == proton_path_str)
+    {
+        Some(p) => p.clone(),
+        None => {
+            return to_cstring(&format!(
+                "Proton not found at path: {}",
+                proton_path_str
+            ));
+        }
+    };
+
+    let log_fn = move |msg: String| {
+        if let Some(cb) = log_cb {
+            let c = CString::new(msg).unwrap_or_default();
+            unsafe { cb(c.as_ptr()) };
+        }
+    };
+
+    match nak_rust::installers::apply_registry_for_game_path(
+        Path::new(prefix),
+        &proton,
+        game,
+        Path::new(install),
+        &log_fn,
+    ) {
+        Ok(()) => ptr::null_mut(),
+        Err(e) => to_cstring(&e),
+    }
+}
+
 // ============================================================================
 // Tier 7: Prefix Symlinks
 // ============================================================================