feat(amm): decode_config in amm_client_ffi (reads token/twap program ids from AMM config)

programs/amm/client-ffi/amm_client_ffi.h

@@ -46,6 +46,16 @@ typedef struct FfiPoolView {
   bool ok;
 } FfiPoolView;
 
+/**
+ * C-ABI mirror of `pool::ConfigView`.
+ */
+typedef struct FfiConfigView {
+  uint32_t token_program_id[8];
+  uint32_t twap_oracle_program_id[8];
+  uint8_t authority[32];
+  bool ok;
+} FfiConfigView;
+
 /**
  * Builds the RISC0 instruction words for a `SwapExactInput`. `amount_in` and
  * `min_out` are little-endian encoded `u128` values (`[u8; 16]`). The
@@ -132,4 +142,14 @@ void amm_client_current_tick_pda(const ProgramId *twap,
  */
 bool amm_client_decode_pool(const uint8_t *bytes, uintptr_t len, struct FfiPoolView *out);
 
+/**
+ * Decodes an `AmmConfig` account's raw bytes into `out`. Returns `false` on
+ * decode failure, leaving `out` unwritten.
+ *
+ * # Safety
+ * `bytes` must be valid for reads of `len` bytes, and `out` must be a
+ * valid, non-null pointer to writable memory for a `FfiConfigView`.
+ */
+bool amm_client_decode_config(const uint8_t *bytes, uintptr_t len, struct FfiConfigView *out);
+
 #endif  /* AMM_CLIENT_FFI_H */

programs/amm/client-ffi/src/lib.rs

@@ -45,6 +45,15 @@ pub struct FfiPoolView {
     pub ok: bool,
 }
 
+/// C-ABI mirror of `pool::ConfigView`.
+#[repr(C)]
+pub struct FfiConfigView {
+    pub token_program_id: [u32; 8],
+    pub twap_oracle_program_id: [u32; 8],
+    pub authority: [u8; 32],
+    pub ok: bool,
+}
+
 /// # Safety
 /// `p` must be a valid, non-null pointer to a readable `[u8; 32]`.
 unsafe fn acc(p: *const [u8; 32]) -> AccountId {
@@ -201,3 +210,30 @@ pub unsafe extern "C" fn amm_client_decode_pool(
         Err(_) => false,
     }
 }
+
+/// Decodes an `AmmConfig` account's raw bytes into `out`. Returns `false` on
+/// decode failure, leaving `out` unwritten.
+///
+/// # Safety
+/// `bytes` must be valid for reads of `len` bytes, and `out` must be a
+/// valid, non-null pointer to writable memory for a `FfiConfigView`.
+#[no_mangle]
+pub unsafe extern "C" fn amm_client_decode_config(
+    bytes: *const u8,
+    len: usize,
+    out: *mut FfiConfigView,
+) -> bool {
+    let b = core::slice::from_raw_parts(bytes, len);
+    match pool::decode_config(b) {
+        Ok(v) => {
+            *out = FfiConfigView {
+                token_program_id: v.token_program_id,
+                twap_oracle_program_id: v.twap_oracle_program_id,
+                authority: v.authority,
+                ok: true,
+            };
+            true
+        }
+        Err(_) => false,
+    }
+}

programs/amm/client-ffi/src/pool.rs

@@ -2,7 +2,7 @@
 //! can read reserves / fees / vault ids without depending on `amm_core`
 //! directly.
 
-use amm_core::PoolDefinition;
+use amm_core::{AmmConfig, PoolDefinition};
 
 pub struct PoolView {
     pub def_a: [u8; 32],
@@ -31,9 +31,25 @@ pub fn decode_pool(bytes: &[u8]) -> Result<PoolView, String> {
     })
 }
 
+pub struct ConfigView {
+    pub token_program_id: [u32; 8],
+    pub twap_oracle_program_id: [u32; 8],
+    pub authority: [u8; 32],
+}
+
+pub fn decode_config(bytes: &[u8]) -> Result<ConfigView, String> {
+    let c: AmmConfig = borsh::from_slice(bytes).map_err(|e| format!("{e:?}"))?;
+    Ok(ConfigView {
+        token_program_id: c.token_program_id,
+        twap_oracle_program_id: c.twap_oracle_program_id,
+        authority: c.authority.into_value(),
+    })
+}
+
 #[cfg(test)]
 mod tests {
     use amm_core::PoolDefinition;
+    use nssa_core::account::AccountId;
 
     use super::*;
 
@@ -44,4 +60,18 @@ mod tests {
         let v = decode_pool(&bytes).unwrap();
         assert_eq!(v.reserve_a, 0);
     }
+
+    #[test]
+    fn decode_config_roundtrip() {
+        let c = AmmConfig {
+            token_program_id: [7u32; 8],
+            twap_oracle_program_id: [9u32; 8],
+            authority: AccountId::new([0u8; 32]),
+        };
+        let bytes = borsh::to_vec(&c).unwrap();
+        let v = decode_config(&bytes).unwrap();
+        assert_eq!(v.token_program_id, [7u32; 8]);
+        assert_eq!(v.twap_oracle_program_id, [9u32; 8]);
+        assert_eq!(v.authority, [0u8; 32]);
+    }
 }