Remove processes cache

Cargo.toml

@@ -9,6 +9,7 @@ crate-type = ["lib", "cdylib"]
 
 [dependencies]
 anyhow = "1.0"
+async-trait = "0.1"
 serde = { version = "1.0.188", features = ["derive"] }
 serde_json = "1.0"
 wasm-bindgen = "0.2.91"
@@ -19,6 +20,9 @@ tsify = { git = "https://github.com/Sosthene00/tsify", branch = "next" }
 # sdk_common = { path = "../sdk_common" }
 sdk_common = { git = "https://git.4nkweb.com/4nk/sdk_common.git", branch = "dev" }
 serde-wasm-bindgen = "0.6.5"
+wasm-bindgen-futures = "0.4"
+futures = "0.3"
+web-sys = { version = "0.3", features = ["Window"] }
 
 [dev-dependencies]
 wasm-bindgen-test = "0.3"

src/api.rs

@@ -21,10 +21,10 @@ use anyhow::Error as AnyhowError;
 use anyhow::Result as AnyhowResult;
 use sdk_common::aes_gcm::aead::{Aead, Payload};
 use sdk_common::crypto::{
-    decrypt_with_key, encrypt_with_key, generate_key, AeadCore, Aes256Gcm, AnkSharedSecretHash, KeyInit, AAD
+    decrypt_with_key, encrypt_with_key, generate_key, verify_merkle_proof, AeadCore, Aes256Gcm, AnkSharedSecretHash, KeyInit, AAD
 };
-use sdk_common::process::{check_tx_for_process_updates, lock_processes, Process, ProcessState};
-use sdk_common::serialization::{OutPointMemberMap, OutPointProcessMap, ciborium_deserialize as common_deserialize};
+use sdk_common::process::{Process, ProcessState};
+use sdk_common::serialization::{OutPointMemberMap, OutPointProcessMap};
 use sdk_common::signature::{AnkHash, AnkMessageHash, AnkValidationNoHash, AnkValidationYesHash, Proof};
 use sdk_common::sp_client::bitcoin::blockdata::fee_rate;
 use sdk_common::sp_client::bitcoin::consensus::{deserialize, serialize};
@@ -65,7 +65,7 @@ use sdk_common::network::{
     NewTxMessage,
 };
 use sdk_common::pcd::{
-    FileBlob, Member, Pcd, PcdCommitments, RoleDefinition, Roles, ValidationRule
+    DataType, FileBlob, Member, Pcd, PcdCommitments, RoleDefinition, Roles, ValidationRule, PCD_VERSION, PcdSerializable
 };
 use sdk_common::prd::{AnkPrdHash, Prd, PrdType};
 use sdk_common::silentpayments::{create_transaction as internal_create_transaction, sign_transaction as internal_sign_tx, TsUnsignedTransaction};
@@ -73,7 +73,7 @@ use sdk_common::sp_client::{FeeRate, OutputSpendStatus, OwnedOutput, Recipient,
 use sdk_common::secrets::SecretsStore;
 
 use crate::user::{lock_local_device, set_new_device, LOCAL_DEVICE};
-use crate::wallet::{generate_sp_wallet, lock_freezed_utxos};
+use crate::wallet::{generate_sp_wallet, lock_freezed_utxos, scan_blocks};
 
 const EMPTYSTATEID: &str = "0000000000000000000000000000000000000000000000000000000000000000";
 
@@ -253,7 +253,6 @@ pub fn get_address() -> ApiResult<String> {
         .get_sp_client()
         .get_receiving_address()
         .to_string();
-    debug!("{}", address);
     Ok(address)
 }
 
@@ -266,8 +265,8 @@ pub fn get_member() -> ApiResult<Member> {
 }
 
 #[wasm_bindgen]
-pub fn restore_device(device_str: String) -> ApiResult<()> {
-    let device: Device = serde_json::from_str(&device_str)?;
+pub fn restore_device(device: JsValue) -> ApiResult<()> {
+    let device: Device = serde_wasm_bindgen::from_value(device)?;
 
     let mut local_device = lock_local_device()?;
 
@@ -347,65 +346,6 @@ pub fn dump_wallet() -> ApiResult<String> {
     Ok(serde_json::to_string(device.get_sp_client()).unwrap())
 }
 
-#[wasm_bindgen]
-pub fn reset_process_cache() -> ApiResult<()> {
-    let mut cached_processes = lock_processes()?;
-
-    *cached_processes = HashMap::new();
-
-    debug_assert!(cached_processes.is_empty());
-
-    Ok(())
-}
-
-#[wasm_bindgen]
-pub fn dump_process_cache() -> ApiResult<String> {
-    let cached_processes = lock_processes()?;
-
-    let serializable_cache = cached_processes
-        .iter()
-        .map(|(outpoint, process)| {
-            (
-                outpoint.to_string(),
-                serde_json::to_value(&process).unwrap(),
-            )
-        })
-        .collect::<serde_json::Map<String, Value>>();
-
-    let json_string = serde_json::to_string(&serializable_cache)
-        .map_err(|e| ApiError::new(format!("Failed to serialize process cache: {}", e)))?;
-
-    Ok(json_string)
-}
-
-#[wasm_bindgen]
-pub fn set_process_cache(processes: JsValue) -> ApiResult<()> {
-    let parsed_processes: HashMap<OutPoint, Process> = serde_wasm_bindgen::from_value(processes)?;
-
-    let mut cached_processes = lock_processes()?;
-
-    if !cached_processes.is_empty() {
-        // Don't overwrite processes in memory
-        return Err(ApiError::new("Processes cache is not empty".to_owned()));
-    }
-
-    *cached_processes = parsed_processes;
-
-    Ok(())
-}
-
-#[wasm_bindgen]
-pub fn add_to_process_cache(process_id: String, process: String) -> ApiResult<()> {
-    let process_id = OutPoint::from_str(&process_id)?;
-    let process: Process = serde_json::from_str(&process)?;
-
-    let mut cached_processes = lock_processes()?;
-
-    cached_processes.insert(process_id, process);
-
-    Ok(())
-}
-
 #[wasm_bindgen]
 pub fn reset_shared_secrets() -> ApiResult<()> {
     let mut shared_secrets = lock_shared_secrets()?;
@@ -434,10 +374,10 @@ pub fn get_pairing_process_id() -> ApiResult<String> {
 }
 
 #[wasm_bindgen]
-pub fn dump_device() -> ApiResult<String> {
+pub fn dump_device() -> ApiResult<Device> {
     let local_device = lock_local_device()?;
 
-    Ok(serde_json::to_string(&local_device.clone())?)
+    Ok(local_device.clone())
 }
 
 #[wasm_bindgen]
@@ -468,7 +408,6 @@ pub fn reset_device() -> ApiResult<()> {
     *device = Device::default();
 
     reset_shared_secrets()?;
-    reset_process_cache()?;
 
     Ok(())
 }
@@ -480,6 +419,60 @@ pub fn get_txid(transaction: String) -> ApiResult<String> {
     Ok(tx.txid().to_string())
 }
 
+#[wasm_bindgen]
+pub fn get_prevouts(transaction: String) -> ApiResult<Vec<String>> {
+    let tx: Transaction = deserialize(&Vec::from_hex(&transaction)?)?;
+
+    Ok(tx.input.iter().map(|input| input.previous_output.to_string()).collect())
+}
+
+#[wasm_bindgen]
+pub fn get_opreturn(transaction: String) -> ApiResult<String> {
+    let tx: Transaction = deserialize(&Vec::from_hex(&transaction)?)?;
+
+    let op_return_outputs: Vec<_> = tx
+        .output
+        .iter()
+        .filter(|o| o.script_pubkey.is_op_return())
+        .collect();
+    if op_return_outputs.len() != 1 {
+        return Err(ApiError::new(
+            "Transaction must contain exactly one op_return output".to_owned(),
+        ));
+    }
+    let data = &op_return_outputs
+        .into_iter()
+        .next()
+        .unwrap()
+        .script_pubkey
+        .as_bytes()[2..];
+    if data.len() != 32 {
+        return Err(ApiError::new("commited data is not 32B long".to_owned()));
+    }
+
+    Ok(data.to_lower_hex_string())
+}
+
+#[wasm_bindgen]
+pub fn process_commit_new_state(mut process: Process, state_id: String, new_tip: String) -> ApiResult<Process> {
+    let state_id_array: [u8; 32] = Vec::from_hex(&state_id)?.try_into().unwrap();
+    let new_state: ProcessState;
+    if let Ok(commited_state) = process.get_state_for_id(&state_id_array) {
+        new_state = commited_state.clone();
+    } else {
+        new_state = ProcessState {
+            commited_in: process.get_process_tip()?,
+            state_id: state_id_array,
+            ..Default::default()
+        };
+    }
+
+    process.remove_all_concurrent_states()?;
+    process.insert_concurrent_state(new_state)?;
+    process.update_states_tip(OutPoint::from_str(&new_tip)?)?;
+    Ok(process)
+}
+
 fn handle_transaction(
     updated: HashMap<OutPoint, OwnedOutput>,
     tx: &Transaction,
@@ -495,27 +488,12 @@ fn handle_transaction(
         local_member = local_device.to_member();
     }
 
-    let op_return: Vec<&sdk_common::sp_client::bitcoin::TxOut> = tx
-        .output
-        .iter()
-        .filter(|o| o.script_pubkey.is_op_return())
-        .collect();
-    if op_return.len() != 1 {
-        return Err(AnyhowError::msg(
-            "Transaction must have exactly one op_return output",
-        ));
-    }
-    let commitment =
-        AnkPrdHash::from_slice(&op_return.first().unwrap().script_pubkey.as_bytes()[2..])?;
-
     // Basically a transaction that destroyed utxo is a transaction we sent.
     let utxo_destroyed: HashMap<&OutPoint, &OwnedOutput> = updated
         .iter()
         .filter(|(outpoint, output)| output.spend_status != OutputSpendStatus::Unspent)
         .collect();
 
-    let mut shared_secrets = lock_shared_secrets()?;
-
     // empty utxo_destroyed means we received this transaction
     if utxo_destroyed.is_empty() {
         let shared_point = sp_utils::receiving::calculate_ecdh_shared_secret(
@@ -524,10 +502,12 @@ fn handle_transaction(
         );
         let shared_secret = AnkSharedSecretHash::from_shared_point(shared_point);
 
+        let mut shared_secrets = lock_shared_secrets()?;
+
         // We keep the shared_secret as unconfirmed
         shared_secrets.add_unconfirmed_secret(shared_secret);
 
-        // We also return it
+        // We also return it for permanent storage
         let mut new_secret = SecretsStore::new();
         new_secret.add_unconfirmed_secret(shared_secret);
 
@@ -565,29 +545,6 @@ fn process_transaction(
 ) -> anyhow::Result<ApiReturn> {
     let tx = deserialize::<Transaction>(&Vec::from_hex(&tx_hex)?)?;
 
-    // Before anything, check if this transaction spends the tip of a process we know about
-    match check_tx_for_process_updates(&tx) {
-        Ok(outpoint) => {
-            let processes = lock_processes()?;
-            let process = processes.get(&outpoint).unwrap();
-            let new_state = process.get_latest_commited_state().unwrap();
-            let diffs = if let Ok(diffs) = create_diffs(&lock_local_device()?, process, new_state, members_list) { diffs } else { vec![] };
-            let updated_process = UpdatedProcess {
-                process_id: outpoint,
-                current_process: process.clone(),
-                diffs,
-                ..Default::default()
-            };
-            let api_return = ApiReturn {
-                updated_process: Some(updated_process),
-                ..Default::default()
-            };
-            debug!("Found an update for process {:?}", api_return.updated_process.as_ref().unwrap().process_id);
-            return Ok(api_return);
-        }
-        Err(e) => debug!("Failed to find process update: {}", e)
-    }
-
     let tweak_data = PublicKey::from_str(&tweak_data_hex)?;
 
     let updated: HashMap<OutPoint, OwnedOutput>;
@@ -598,9 +555,12 @@ fn process_transaction(
 
     if updated.len() > 0 {
         return handle_transaction(updated, &tx, tweak_data);
+    } else {
+        log::debug!("Transaction is not ours");
+        return Ok(ApiReturn {
+            ..Default::default()
+        });
     }
-
-    Err(anyhow::Error::msg("Transaction is not our"))
 }
 
 #[wasm_bindgen]
@@ -609,7 +569,7 @@ pub fn parse_new_tx(new_tx_msg: String, block_height: u32, members_list: OutPoin
 
     if let Some(error) = new_tx.error {
         return Err(ApiError::new(format!(
-            "NewTx returned with an error: {}",
+            "NewTx message returned with an error: {}",
             error
         )));
     }
@@ -743,6 +703,7 @@ fn handle_prd(
     prd: Prd,
     secret: AnkSharedSecretHash,
     members_list: &OutPointMemberMap,
+    processes: &OutPointProcessMap
 ) -> AnyhowResult<ApiReturn> {
     debug!("handle_prd: {:#?}", prd);
     // Connect is a bit different here because there's no associated process
@@ -753,13 +714,10 @@ fn handle_prd(
 
     let outpoint = prd.process_id;
 
-    let mut processes = lock_processes()?;
-    let relevant_process = match processes.entry(outpoint) {
-        std::collections::hash_map::Entry::Occupied(entry) => entry.into_mut(),
-        std::collections::hash_map::Entry::Vacant(entry) => {
-            debug!("Creating new process for outpoint: {}", outpoint);
-            entry.insert(Process::new(outpoint))
-        }
+    let mut relevant_process: Process = if let Some(relevant_process) = processes.0.get(&outpoint) {
+        relevant_process.clone()
+    } else {
+        Process::new(outpoint)
     };
 
     match prd.prd_type {
@@ -973,18 +931,19 @@ fn handle_prd(
 fn handle_decrypted_message(
     secret: AnkSharedSecretHash,
     plain: Vec<u8>,
-    members_list: &OutPointMemberMap
+    members_list: &OutPointMemberMap,
+    processes: &OutPointProcessMap
 ) -> anyhow::Result<ApiReturn> {
     let local_address: SilentPaymentAddress = lock_local_device()?.get_address();
     if let Ok(prd) = Prd::extract_from_message(&plain, local_address) {
-        handle_prd(prd, secret, members_list)
+        handle_prd(prd, secret, members_list, processes)
     } else {
         Err(anyhow::Error::msg("Failed to handle decrypted message"))
     }
 }
 
 #[wasm_bindgen]
-pub fn parse_cipher(cipher_msg: String, members_list: OutPointMemberMap) -> ApiResult<ApiReturn> {
+pub fn parse_cipher(cipher_msg: String, members_list: OutPointMemberMap, processes: OutPointProcessMap) -> ApiResult<ApiReturn> {
     // Check that the cipher is not empty or too long
     if cipher_msg.is_empty() || cipher_msg.len() > MAX_PRD_PAYLOAD_SIZE {
         return Err(ApiError::new(
@@ -996,7 +955,7 @@ pub fn parse_cipher(cipher_msg: String, members_list: OutPointMemberMap) -> ApiR
 
     let decrypt_res = lock_shared_secrets()?.try_decrypt(&cipher);
     if let Ok((secret, plain)) = decrypt_res {
-        return handle_decrypted_message(secret, plain, &members_list)
+        return handle_decrypted_message(secret, plain, &members_list, &processes)
             .map_err(|e| ApiError::new(format!("Failed to handle decrypted message: {}", e)));
     }
 
@@ -1115,7 +1074,7 @@ pub fn create_transaction(addresses: Vec<String>, fee_rate: u32) -> ApiResult<Ap
     // We mark the utxos in the inputs as spent to prevent accidental double spends
     for input in &unsigned_tx.unsigned_tx.as_ref().unwrap().input {
         if let Some(output) = outputs.get_mut(&input.previous_output) {
-            output.spend_status = OutputSpendStatus::Spent(new_txid.to_string());
+            output.spend_status = OutputSpendStatus::Spent(new_txid.to_byte_array());
         }
     }
 
@@ -1198,15 +1157,6 @@ pub fn create_new_process(
 
     process.insert_concurrent_state(new_state.clone())?;
 
-    {
-        let mut processes = lock_processes()?;
-        // If we already have an entry with this outpoint, something's wrong
-        if processes.contains_key(&process_id) {
-            return Err(ApiError::new("There's already a process for this outpoint".to_owned()));
-        }
-        processes.insert(process_id, process.clone());
-    }
-
     let commit_msg = CommitMessage::new(
         process_id, 
         pcd_commitment, 
@@ -1257,18 +1207,19 @@ pub fn update_process(
         roles.clone()
     )?;
 
-    // We compare the new state with the previous one
-    let last_state_merkle_root = &prev_state.state_id;
+    // TODO duplicate check is broken
+    // // We compare the new state with the previous one
+    // let last_state_merkle_root = &prev_state.state_id;
 
-    if *last_state_merkle_root == new_state.state_id {
-        return Err(ApiError::new("new proposed state is identical to the previous commited state".to_owned()));
-    }
+    // if *last_state_merkle_root == new_state.state_id {
+    //     return Err(ApiError::new("new proposed state is identical to the previous commited state".to_owned()));
+    // }
 
-    // We check that we don't have already a similar concurrent state
-    let concurrent_processes = process.get_latest_concurrent_states()?;
-    if concurrent_processes.iter().any(|p| p.state_id == new_state.state_id) {
-        return Err(ApiError::new("New state already known".to_owned()));
-    }
+    // // We check that we don't have already a similar concurrent state
+    // let concurrent_processes = process.get_latest_concurrent_states()?;
+    // if concurrent_processes.iter().any(|p| p.state_id == new_state.state_id) {
+    //     return Err(ApiError::new("New state already known".to_owned()));
+    // }
 
     let diffs = create_diffs(&lock_local_device()?, &process, &new_state, &members_list)?;
 
@@ -1279,22 +1230,14 @@ pub fn update_process(
     for (field, plain_value) in new_attributes.iter() {
         let hash = new_state.pcd_commitment.get(field).ok_or(anyhow::Error::msg("Missing commitment"))?;
         let key = generate_key(&mut rng);
+        let cipher = encrypt_with_key(&key, plain_value.as_slice())?;
         new_state.keys.insert(field.to_owned(), key);
-        let serialized = serde_json::to_string(plain_value)?;
-        let cipher = encrypt_with_key(&key, serialized.as_bytes())?;
         encrypted_data.insert(hash.to_lower_hex_string(), cipher.to_lower_hex_string());
     }
 
     // Add the new state to the process
     process.insert_concurrent_state(new_state.clone())?;
 
-    {
-        // save the process to wasm memory
-        let mut processes = lock_processes()?;
-        // To keep it simple, assume that db is true and replace what we have in memory
-        processes.insert(process_id, process.clone());
-    }
-
     let updated_process = UpdatedProcess {
         process_id,
         current_process: process,
@@ -1451,7 +1394,8 @@ pub fn create_update_message(
             }
 
             // We shouldn't ever have error here since we already checked above
-            let shared_secret = shared_secrets.get_secret_for_address(sp_address.as_str().try_into()?).unwrap();
+            let shared_secret = shared_secrets.get_secret_for_address(sp_address.as_str().try_into()?)
+                .ok_or(AnyhowError::msg("Failed to retrieve secret".to_owned()))?;
 
             let cipher = encrypt_with_key(shared_secret.as_byte_array(), prd_msg.as_bytes())?;
             ciphers.push(cipher.to_lower_hex_string());
@@ -1709,30 +1653,143 @@ pub fn encode_json(json_data: JsValue) -> ApiResult<Pcd> {
     Ok(res)
 }
 
-#[wasm_bindgen]
-pub fn encode_value(value: JsValue) -> ApiResult<Vec<u8>> {
-    let res = sdk_common::serialization::ciborium_serialize(&serde_wasm_bindgen::from_value(value)?)?;
-    Ok(res)
-}
-
 #[wasm_bindgen]
 pub fn decode_value(value: Vec<u8>) -> ApiResult<JsValue> {
-    if let Ok(deserialized) = sdk_common::serialization::ciborium_deserialize::<FileBlob>(&value) {
-        let u8IntArray = Uint8Array::from(deserialized.data.as_slice());
+    // Try FileBlob first
+    if let Ok(file_blob) = sdk_common::pcd::FileBlob::deserialize_from_pcd(&value) {
+        let u8IntArray = Uint8Array::from(file_blob.data.as_slice());
         let res = Object::new();
-        Reflect::set(&res, &JsValue::from_str("type"), &JsValue::from_str(&deserialized.r#type)); 
-        Reflect::set(&res, &JsValue::from_str("data"), &JsValue::from(u8IntArray));
-        Ok(JsValue::from(res))
-    } else {
-        let res: Value = sdk_common::serialization::ciborium_deserialize(&value)?;
-        return Ok(serde_wasm_bindgen::to_value(&res)?);
+        Reflect::set(&res, &JsValue::from_str("type"), &JsValue::from_str(&file_blob.r#type)).unwrap();
+        Reflect::set(&res, &JsValue::from_str("data"), &JsValue::from(u8IntArray)).unwrap();
+        return Ok(JsValue::from(res));
     }
+    // Try JSON next
+    if let Ok(json) = serde_json::Value::deserialize_from_pcd(&value) {
+        return Ok(serde_wasm_bindgen::to_value(&json)?);
+    }
+    Err(ApiError::new("Invalid or unsupported PCD data".to_owned()))
 }
 
 #[wasm_bindgen]
 pub fn hash_value(value: JsValue, commited_in: String, label: String) -> ApiResult<String> {
     let outpoint = OutPoint::from_str(&commited_in)?;
-    let encoded_value = sdk_common::serialization::ciborium_serialize(&serde_wasm_bindgen::from_value::<FileBlob>(value)?)?;
+    let encoded_value = if let Ok(file_blob) = serde_wasm_bindgen::from_value::<FileBlob>(value.clone()) {
+        file_blob.serialize_to_pcd()?
+    } else if let Ok(json) = serde_wasm_bindgen::from_value::<Value>(value) {
+        json.serialize_to_pcd()?
+    } else {
+        return Err(ApiError::new("Invalid or unsupported PCD data".to_owned()));
+    };
     let hash = AnkPcdHash::from_pcd_value(encoded_value.as_slice(), label.as_bytes(), &outpoint);
     Ok(hash.as_byte_array().to_lower_hex_string())
 }
+
+#[wasm_bindgen]
+pub async fn scan_blocks_async(n_blocks_to_scan: u32, blindbit_url: String, tip_height: u32, with_cutthrough: bool) -> ApiResult<()> {
+    match scan_blocks(n_blocks_to_scan, &blindbit_url, tip_height, with_cutthrough).await {
+        Ok(()) => Ok(()),
+        Err(e) => Err(ApiError::new(
+            format!("Scan failed: {}", e)
+        ))
+    }
+}
+
+#[derive(Tsify, Serialize, Deserialize)]
+#[tsify(into_wasm_abi, from_wasm_abi)]
+#[allow(non_camel_case_types)]
+pub struct MerkleProofResult {
+    pub proof: String,
+    pub root: String,
+    pub attribute: String,
+    pub attribute_index: usize,
+    pub total_leaves_count: usize,
+}
+
+#[wasm_bindgen]
+/// Generate a merkle proof for a specific attribute in a process state.
+/// 
+/// This function creates a merkle proof that proves the existence of a specific attribute
+/// in a given state of a process. The proof can be used to verify that the attribute
+/// was indeed part of the state without revealing the entire state.
+/// 
+/// # Arguments
+/// * `process_state` - The process state object as a JavaScript value
+/// * `attribute_name` - The name of the attribute to generate a proof for
+/// 
+/// # Returns
+/// A MerkleProofResult object containing:
+/// * `proof` - The merkle proof as a hex string
+/// * `root` - The merkle root (state_id) as a hex string
+/// * `attribute` - The attribute name that was proven
+/// * `attribute_index` - The index of the attribute in the merkle tree
+/// * `total_leaves_count` - The total number of leaves in the merkle tree
+/// 
+/// # Errors
+/// * "Failed to deserialize process state" - If the process state cannot be deserialized from JsValue
+/// * "Attribute not found in state" - If the attribute doesn't exist in the state
+pub fn get_merkle_proof(process_state: JsValue, attribute_name: String) -> ApiResult<MerkleProofResult> {
+    // Deserialize the process state from JsValue
+    let state: ProcessState = serde_wasm_bindgen::from_value(process_state)
+        .map_err(|_| ApiError::new("Failed to deserialize process state".to_owned()))?;
+    
+    // Create merkle tree from the PCD commitments
+    let merkle_tree = state.pcd_commitment.create_merkle_tree()?;
+    
+    // Find the index of the attribute in the commitments
+    let attribute_index = state.pcd_commitment.find_index_of(&attribute_name)
+        .ok_or(ApiError::new("Attribute not found in state".to_owned()))?;
+
+    // Generate the merkle proof for the attribute
+    let proof = merkle_tree.proof(&[attribute_index]);
+    
+    // Convert the proof to a format that can be serialized to JavaScript
+    let proof_bytes = proof.to_bytes();
+    let proof_hex = proof_bytes.to_lower_hex_string();
+    
+    Ok(MerkleProofResult {
+        proof: proof_hex,
+        root: state.state_id.to_lower_hex_string(),
+        attribute: attribute_name,
+        attribute_index: attribute_index,
+        total_leaves_count: merkle_tree.leaves_len(),
+    })
+}
+
+#[wasm_bindgen]
+/// Validate a merkle proof for a specific attribute.
+/// 
+/// This function verifies that a merkle proof is valid and proves the existence
+/// of a specific attribute in a given state. It checks that the proof correctly
+/// leads to the claimed root when combined with the attribute hash.
+/// 
+/// # Arguments
+/// * `proof_result` - a JsValue expected to contain a MerkleProofResult with the proof and metadata
+/// * `hash` - The hash of the attribute data as a hex string (the leaf value)
+/// 
+/// # Returns
+/// A boolean indicating whether the proof is valid
+/// 
+/// # Errors
+/// * "serde_wasm_bindgen deserialization error" - If the proof is not a valid MerkleProofResult
+/// * "Invalid proof format" - If the proof cannot be parsed
+/// * "Invalid hash format" - If the hash is not a valid 32-byte hex string
+/// * "Invalid root format" - If the root is not a valid 32-byte hex string
+pub fn validate_merkle_proof(proof_result: JsValue, hash: String) -> ApiResult<bool> {
+    let proof_result: MerkleProofResult = serde_wasm_bindgen::from_value(proof_result)?;
+    let root_bytes: [u8; 32] = Vec::from_hex(&proof_result.root)?
+        .try_into()
+        .map_err(|_| ApiError::new("Invalid root format".to_owned()))?;
+    
+    let proof_bytes = Vec::from_hex(&proof_result.proof)
+        .map_err(|_| ApiError::new("Invalid proof format".to_owned()))?;
+
+    let index = proof_result.attribute_index;
+    let total_leaves_count = proof_result.total_leaves_count;
+
+    let hash_bytes: [u8; 32] = Vec::from_hex(&hash)?.try_into()
+        .map_err(|_| ApiError::new("Invalid hash format".to_owned()))?;
+    
+    let res = verify_merkle_proof(&proof_bytes, &root_bytes, index, &hash_bytes, total_leaves_count)?;
+    
+    Ok(res)
+}

src/wallet.rs

@@ -1,17 +1,17 @@
 use std::{
-    collections::HashSet,
-    sync::{Mutex, MutexGuard, OnceLock},
+    collections::{HashMap, HashSet}, ops::RangeInclusive, pin::Pin, sync::{atomic::AtomicBool, Arc, Mutex, MutexGuard, OnceLock}, time::Instant
 };
 
-use anyhow::Error;
+use anyhow::{bail, Result, Error};
+use futures::Stream;
 use rand::Rng;
-use sdk_common::sp_client::{
-    bitcoin::{secp256k1::SecretKey, Network, OutPoint},
-    silentpayments::SilentPaymentAddress,
-    SpClient, SpendKey,
-};
+use sdk_common::{log, sp_client::{
+    bitcoin::{absolute::Height, hashes::{sha256, Hash}, secp256k1::{PublicKey, SecretKey}, Amount, BlockHash, Network, OutPoint}, silentpayments::SilentPaymentAddress, BlindbitBackend, BlockData, FilterData, OutputSpendStatus, OwnedOutput, SpClient, SpScanner, SpendKey, SpentIndexData, Updater, UtxoData
+}, updates::StateUpdater};
 
-use crate::MutexExt;
+use sdk_common::sp_client::ChainBackendWasm;
+
+use crate::{user::lock_local_device, MutexExt};
 
 pub static FREEZED_UTXOS: OnceLock<Mutex<HashSet<OutPoint>>> = OnceLock::new();
 
@@ -29,3 +29,273 @@ pub fn generate_sp_wallet(network: Network) -> anyhow::Result<SpClient> {
         network,
     )
 }
+
+pub struct WasmSpScanner<'a> {
+    updater: Box<dyn Updater + Sync>,
+    backend: BlindbitBackend,
+    client: SpClient,
+    keep_scanning: &'a AtomicBool,
+    owned_outpoints: HashSet<OutPoint>,
+}
+
+impl<'a> WasmSpScanner<'a> {
+    pub fn new(
+        client: SpClient,
+        updater: Box<dyn Updater + Sync>,
+        backend: BlindbitBackend,
+        owned_outpoints: HashSet<OutPoint>,
+        keep_scanning: &'a AtomicBool,
+    ) -> Self {
+        Self {
+            client,
+            updater,
+            backend,
+            owned_outpoints,
+            keep_scanning,
+        }
+    }
+
+    pub async fn scan_blocks(
+        &mut self,
+        start: Height,
+        end: Height,
+        dust_limit: Amount,
+        with_cutthrough: bool,
+    ) -> Result<()> {
+        if start > end {
+            bail!("bigger start than end: {} > {}", start, end);
+        }
+
+        log::info!("start: {} end: {}", start, end);
+        let start_time: Instant = Instant::now();
+
+        // get block data stream
+        let range = start.to_consensus_u32()..=end.to_consensus_u32();
+        let block_data_stream = self.backend.get_block_data_for_range(range, dust_limit, with_cutthrough);
+
+        // process blocks using block data stream
+        self.process_blocks(start, end, block_data_stream).await?;
+
+        // time elapsed for the scan
+        log::info!(
+            "Blindbit scan complete in {} seconds",
+            start_time.elapsed().as_secs()
+        );
+
+        Ok(())
+    }
+
+    async fn process_blocks(
+        &mut self,
+        start: Height,
+        end: Height,
+        block_data_stream: Pin<Box<dyn Stream<Item = Result<BlockData>>>>,
+    ) -> Result<()> {
+        use sdk_common::sp_client::futures::StreamExt;
+        use std::time::{Duration, Instant};
+
+        let mut update_time = Instant::now();
+        let mut stream = block_data_stream;
+
+        while let Some(blockdata) = stream.next().await {
+            let blockdata = blockdata?;
+            let blkheight = blockdata.blkheight;
+            let blkhash = blockdata.blkhash;
+
+            // stop scanning and return if interrupted
+            if self.should_interrupt() {
+                self.save_state()?;
+                return Ok(());
+            }
+
+            let mut save_to_storage = false;
+
+            // always save on last block or after 30 seconds since last save
+            if blkheight == end || update_time.elapsed() > Duration::from_secs(30) {
+                save_to_storage = true;
+            }
+
+            let (found_outputs, found_inputs) = self.process_block(blockdata).await?;
+
+            if !found_outputs.is_empty() {
+                save_to_storage = true;
+                self.record_outputs(blkheight, blkhash, found_outputs)?;
+            }
+
+            if !found_inputs.is_empty() {
+                save_to_storage = true;
+                self.record_inputs(blkheight, blkhash, found_inputs)?;
+            }
+
+            // tell the updater we scanned this block
+            self.record_progress(start, blkheight, end)?;
+
+            if save_to_storage {
+                self.save_state()?;
+                update_time = Instant::now();
+            }
+        }
+
+        Ok(())
+    }
+
+    async fn process_block(
+        &mut self,
+        blockdata: BlockData,
+    ) -> Result<(HashMap<OutPoint, OwnedOutput>, HashSet<OutPoint>)> {
+        let BlockData {
+            blkheight,
+            tweaks,
+            new_utxo_filter,
+            spent_filter,
+            ..
+        } = blockdata;
+
+        let outs = self
+            .process_block_outputs(blkheight, tweaks, new_utxo_filter)
+            .await?;
+
+        // after processing outputs, we add the found outputs to our list
+        self.owned_outpoints.extend(outs.keys());
+
+        let ins = self.process_block_inputs(blkheight, spent_filter).await?;
+
+        // after processing inputs, we remove the found inputs
+        self.owned_outpoints.retain(|item| !ins.contains(item));
+
+        Ok((outs, ins))
+    }
+
+    async fn process_block_outputs(
+        &self,
+        blkheight: Height,
+        tweaks: Vec<PublicKey>,
+        new_utxo_filter: FilterData,
+    ) -> Result<HashMap<OutPoint, OwnedOutput>> {
+        // Implementation for processing block outputs
+        // This is a placeholder - you'll need to implement the actual logic
+        Ok(HashMap::new())
+    }
+
+    async fn process_block_inputs(
+        &self,
+        blkheight: Height,
+        spent_filter: FilterData,
+    ) -> Result<HashSet<OutPoint>> {
+        // Implementation for processing block inputs
+        // This is a placeholder - you'll need to implement the actual logic
+        Ok(HashSet::new())
+    }
+
+    fn should_interrupt(&self) -> bool {
+        !self
+            .keep_scanning
+            .load(std::sync::atomic::Ordering::Relaxed)
+    }
+
+    fn save_state(&mut self) -> Result<()> {
+        self.updater.save_to_persistent_storage()
+    }
+
+    fn record_outputs(
+        &mut self,
+        height: Height,
+        block_hash: BlockHash,
+        outputs: HashMap<OutPoint, OwnedOutput>,
+    ) -> Result<()> {
+        self.updater.record_block_outputs(height, block_hash, outputs)
+    }
+
+    fn record_inputs(
+        &mut self,
+        height: Height,
+        block_hash: BlockHash,
+        inputs: HashSet<OutPoint>,
+    ) -> Result<()> {
+        self.updater.record_block_inputs(height, block_hash, inputs)
+    }
+
+    fn record_progress(&mut self, start: Height, current: Height, end: Height) -> Result<()> {
+        self.updater.record_scan_progress(start, current, end)
+    }
+
+    // Override the default get_input_hashes implementation to use owned_outpoints
+    fn get_input_hashes(&self, blkhash: BlockHash) -> Result<HashMap<[u8; 8], OutPoint>> {
+        let mut map: HashMap<[u8; 8], OutPoint> = HashMap::new();
+
+        for outpoint in &self.owned_outpoints {
+            let mut arr = [0u8; 68];
+            arr[..32].copy_from_slice(&outpoint.txid.to_raw_hash().to_byte_array());
+            arr[32..36].copy_from_slice(&outpoint.vout.to_le_bytes());
+            arr[36..].copy_from_slice(&blkhash.to_byte_array());
+            let hash = sha256::Hash::hash(&arr);
+
+            let mut res = [0u8; 8];
+            res.copy_from_slice(&hash[..8]);
+
+            map.insert(res, outpoint.clone());
+        }
+
+        Ok(map)
+    }
+}
+
+pub async fn scan_blocks(mut n_blocks_to_scan: u32, blindbit_url: &str, tip_height: u32, with_cutthrough: bool) -> anyhow::Result<()> {
+    log::info!("Starting a rescan");
+
+    // Get all the data we need upfront, before any async operations
+    let device = lock_local_device()?;
+    let sp_wallet = device.get_sp_wallet();
+    let scan_height = sp_wallet.get_last_scan();
+
+    // 0 means scan to tip
+    if n_blocks_to_scan == 0 {
+        n_blocks_to_scan = tip_height - scan_height;
+    }
+
+    let start = scan_height + 1;
+    let end = if scan_height + n_blocks_to_scan <= tip_height {
+        scan_height + n_blocks_to_scan
+    } else {
+        tip_height
+    };
+
+    if start > end {
+        return Ok(());
+    }
+
+    let updater = StateUpdater::new();
+    let backend = BlindbitBackend::new(blindbit_url.to_string())?;
+
+    let owned_outpoints = sp_wallet.get_unspent_outputs().keys().map(|o| *o).collect();
+
+    let keep_scanning = Arc::new(AtomicBool::new(true));
+
+    log::info!("start: {} end: {}", start, end);
+    let start_time = Instant::now();
+    let mut scanner = WasmSpScanner::new(
+        sp_wallet.get_sp_client().clone(),
+        Box::new(updater),
+        backend,
+        owned_outpoints,
+        &keep_scanning,
+    );
+
+    let dust_limit = Amount::from_sat(0); // We don't really have a dust limit for this use case
+    scanner
+        .scan_blocks(
+            Height::from_consensus(start)?,
+            Height::from_consensus(end)?,
+            dust_limit,
+            with_cutthrough,
+        )
+        .await?;
+
+    // time elapsed for the scan
+    log::info!(
+        "Scan complete in {} seconds",
+        start_time.elapsed().as_secs()
+    );
+
+    Ok(())
+}