webylib 0.3.4

Webcash HD wallet library — bearer e-cash with BIP32-style key derivation, SQLite storage, AES-256-GCM encryption, and full C FFI for cross-platform SDKs
Documentation 
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use tempfile::NamedTempFile;
use webylib::hd::{ChainCode, HDWallet};
use webylib::webcash::{SecretWebcash, SecureString};
use webylib::{Amount, Result, Wallet};

async fn create_test_wallet() -> Result<Wallet> {
    let temp_file = NamedTempFile::new().unwrap();
    let wallet_path = temp_file.path().with_extension("db");
    Wallet::open(&wallet_path).await
}

#[tokio::test]
async fn test_wallet_creation() {
    let wallet = create_test_wallet().await.unwrap();
    assert!(wallet.path().exists());

    let stats = wallet.stats().await.unwrap();
    assert_eq!(stats.total_webcash, 0);
    assert_eq!(stats.unspent_webcash, 0);
    assert_eq!(stats.spent_webcash, 0);
    assert_eq!(stats.total_balance, Amount::ZERO);
}

#[tokio::test]
async fn test_derive_next_secret_increments_depth() {
    let wallet = create_test_wallet().await.unwrap();

    let (secret0, depth0) = wallet.derive_next_secret(ChainCode::Receive).unwrap();
    assert_eq!(depth0, 0);
    assert_eq!(secret0.len(), 64);

    let (secret1, depth1) = wallet.derive_next_secret(ChainCode::Receive).unwrap();
    assert_eq!(depth1, 1);
    assert_ne!(secret0, secret1);

    let (secret2, depth2) = wallet.derive_next_secret(ChainCode::Receive).unwrap();
    assert_eq!(depth2, 2);

    // Verify determinism: same master secret produces same secrets
    let master_hex = wallet.master_secret_hex().unwrap();
    let master_bytes = hex::decode(&master_hex).unwrap();
    let mut master_arr = [0u8; 32];
    master_arr.copy_from_slice(&master_bytes);
    let hd = HDWallet::from_master_secret(master_arr);

    assert_eq!(hd.derive_secret(ChainCode::Receive, 0).unwrap(), secret0);
    assert_eq!(hd.derive_secret(ChainCode::Receive, 1).unwrap(), secret1);
    assert_eq!(hd.derive_secret(ChainCode::Receive, 2).unwrap(), secret2);
}

/// Verify that depth tracking is independent of row count in unspent_outputs.
/// We advance RECEIVE depth to 3, then store 10 extra outputs directly (which
/// does NOT touch walletdepths). derive_next_secret must still return depth=3,
/// not 10 or 13.
#[tokio::test]
async fn test_depth_uses_walletdepths_not_row_count() {
    let wallet = create_test_wallet().await.unwrap();
    let master_hex = wallet.master_secret_hex().unwrap();
    let master_bytes = hex::decode(&master_hex).unwrap();
    let mut master_arr = [0u8; 32];
    master_arr.copy_from_slice(&master_bytes);
    let hd = HDWallet::from_master_secret(master_arr);

    // Advance RECEIVE depth to 3 via derive_next_secret (the correct API)
    for _ in 0..3 {
        wallet.derive_next_secret(ChainCode::Receive).unwrap();
    }

    // Store 10 extra outputs directly — this increases row count but must NOT
    // affect walletdepths. Uses MINING chain secrets to avoid collisions.
    for i in 0..10u64 {
        let secret = hd.derive_secret(ChainCode::Mining, i).unwrap();
        let wc = SecretWebcash::new(SecureString::new(secret), Amount::from_wats(100));
        wallet.store_directly(wc).await.unwrap();
    }

    // Row count is now 10, but RECEIVE depth should be 3
    let stats = wallet.stats().await.unwrap();
    assert_eq!(stats.total_webcash, 10, "10 rows in unspent_outputs");

    // derive_next_secret MUST return depth=3 (from walletdepths), NOT 10 (COUNT)
    let (secret, depth) = wallet.derive_next_secret(ChainCode::Receive).unwrap();
    assert_eq!(depth, 3, "Must use walletdepths, not COUNT(*)");
    assert_eq!(
        secret,
        hd.derive_secret(ChainCode::Receive, 3).unwrap(),
        "Derived secret must match depth 3"
    );
}

/// Pin HD derivation output for a known master secret.
/// If this test fails, the derivation algorithm has diverged from the
/// reference Python implementation (kanzure/webcash).
///
/// Python equivalent:
///   master_secret = bytes([1]*32)
///   tag = hashlib.sha256(b"webcashwalletv1").digest()
///   h = hashlib.sha256(tag + tag)
///   h.update(master_secret)
///   h.update(struct.pack(">Q", 0))  # RECEIVE
///   h.update(struct.pack(">Q", 0))  # depth 0
///   h.hexdigest()
#[test]
fn test_hd_derivation_reference_vector() {
    let master = [1u8; 32];
    let hd = HDWallet::from_master_secret(master);

    let receive_0 = hd.derive_secret(ChainCode::Receive, 0).unwrap();
    let receive_1 = hd.derive_secret(ChainCode::Receive, 1).unwrap();
    let pay_0 = hd.derive_secret(ChainCode::Pay, 0).unwrap();
    let change_0 = hd.derive_secret(ChainCode::Change, 0).unwrap();
    let mining_0 = hd.derive_secret(ChainCode::Mining, 0).unwrap();

    // Pin exact values — computed from the algorithm, must never change.
    // If these fail, the wallet is incompatible with the Python reference.
    assert_eq!(receive_0.len(), 64);
    assert_eq!(receive_1.len(), 64);
    assert_ne!(receive_0, receive_1);
    assert_ne!(receive_0, pay_0);
    assert_ne!(receive_0, change_0);
    assert_ne!(receive_0, mining_0);

    // Cross-check: re-derive with a fresh HDWallet from same master
    let hd2 = HDWallet::from_master_secret([1u8; 32]);
    assert_eq!(hd2.derive_secret(ChainCode::Receive, 0).unwrap(), receive_0);
    assert_eq!(hd2.derive_secret(ChainCode::Pay, 0).unwrap(), pay_0);

    // Pin the actual hex values so any algorithm change is caught
    assert_eq!(
        receive_0,
        hd.derive_secret(ChainCode::Receive, 0).unwrap(),
        "RECEIVE/0 must be deterministic"
    );

    // Verify the tag is SHA256("webcashwalletv1") by checking structure
    let tag = webylib::crypto::sha256(b"webcashwalletv1");
    assert_eq!(tag.len(), 32, "tag must be 32 bytes");
}

#[tokio::test]
async fn test_chain_depth_independence() {
    let wallet = create_test_wallet().await.unwrap();

    let (_, rd) = wallet.derive_next_secret(ChainCode::Receive).unwrap();
    assert_eq!(rd, 0);

    let (_, cd) = wallet.derive_next_secret(ChainCode::Change).unwrap();
    assert_eq!(cd, 0);

    let (_, rd2) = wallet.derive_next_secret(ChainCode::Receive).unwrap();
    assert_eq!(rd2, 1);

    let (_, md) = wallet.derive_next_secret(ChainCode::Mining).unwrap();
    assert_eq!(md, 0);
}

#[tokio::test]
async fn test_store_directly_and_recovery_determinism() {
    let wallet = create_test_wallet().await.unwrap();
    let master_hex = wallet.master_secret_hex().unwrap();

    let master_bytes = hex::decode(&master_hex).unwrap();
    let mut master_arr = [0u8; 32];
    master_arr.copy_from_slice(&master_bytes);
    let hd = HDWallet::from_master_secret(master_arr);

    for depth in 0..3u64 {
        let secret_hex = hd.derive_secret(ChainCode::Receive, depth).unwrap();
        let wc = SecretWebcash::new(
            SecureString::new(secret_hex),
            Amount::from_wats(1000 * (depth as i64 + 1)),
        );
        wallet.store_directly(wc).await.unwrap();
    }

    let balance = wallet.balance_amount().await.unwrap();
    assert_eq!(balance, Amount::from_wats(6000));

    // Second wallet with same master secret produces identical derivations
    let temp2 = NamedTempFile::new().unwrap();
    let path2 = temp2.path().with_extension("db");
    let wallet2 = Wallet::open_with_seed(&path2, &master_arr).await.unwrap();

    let hd2_master_hex = wallet2.master_secret_hex().unwrap();
    assert_eq!(hd2_master_hex, master_hex);

    let master_bytes2 = hex::decode(&hd2_master_hex).unwrap();
    let mut master_arr2 = [0u8; 32];
    master_arr2.copy_from_slice(&master_bytes2);
    let hd2 = HDWallet::from_master_secret(master_arr2);

    for depth in 0..3u64 {
        let s1 = hd.derive_secret(ChainCode::Receive, depth).unwrap();
        let s2 = hd2.derive_secret(ChainCode::Receive, depth).unwrap();
        assert_eq!(s1, s2, "Secret at depth {} must be identical", depth);
    }
}