// Bridge API — thin wrappers that delegate to ccc_rust providers.
//
// No cryptographic logic here; only type conversions and registry lookups.

use ccc_crypto_core::{KemProvider, ProviderRegistry};
use ccc_crypto_wolfssl::WolfSslProvider;

use crate::api::dto::*;

/// Trace-level bridge logging. Visible only when `RUST_LOG=trace` (or
/// equivalent) is set; compiled out in release builds when the `log` crate's
/// `release_max_level_off` feature is enabled.
macro_rules! dbg_bridge {
    ($($arg:tt)*) => {
        log::trace!("[ccc-bridge] {}", format!($($arg)*));
    };
}

// ── Helpers ──────────────────────────────────────────────────────────────────

/// Default provider name used when the caller doesn't specify one.
const DEFAULT_PROVIDER: &str = "wolfssl";

/// Get the default provider from the registry or return an error.
fn default_provider(
) -> Result<std::sync::Arc<dyn ccc_crypto_core::provider::CryptoProvider>, CccCryptoError> {
    ProviderRegistry::global()
        .get(DEFAULT_PROVIDER)
        .ok_or_else(|| {
            CccCryptoError::InternalError(format!(
                "provider '{DEFAULT_PROVIDER}' not registered — call ccc_init() first"
            ))
        })
}

/// A lazily-initialised KemProvider instance.
///
/// `KemProvider` is not part of the `CryptoProvider` supertrait, so we keep
/// a standalone `WolfSslProvider` for KEM operations.
fn kem_provider() -> &'static WolfSslProvider {
    use std::sync::OnceLock;
    static KEM: OnceLock<WolfSslProvider> = OnceLock::new();
    KEM.get_or_init(WolfSslProvider::new)
}

// ── Init ─────────────────────────────────────────────────────────────────────

/// Initialise the CCC cryptographic subsystem.
///
/// Registers the wolfSSL provider in the global registry.
/// Safe to call multiple times (idempotent).
pub fn ccc_init() {
    dbg_bridge!("ccc_init: enter");
    flutter_rust_bridge::setup_default_user_utils();
    if !ProviderRegistry::global().contains(DEFAULT_PROVIDER) {
        ccc_crypto_wolfssl::init();
    }
    dbg_bridge!("ccc_init: exit");
}

// ── Provider info ────────────────────────────────────────────────────────────

/// List all registered provider names.
#[flutter_rust_bridge::frb(sync)]
pub fn ccc_list_providers() -> Vec<String> {
    dbg_bridge!("ccc_list_providers");
    ProviderRegistry::global().list()
}

/// Return the capabilities of the default provider.
pub fn ccc_capabilities() -> Result<CccCapabilities, CccCryptoError> {
    dbg_bridge!("ccc_capabilities");
    let provider = default_provider()?;
    Ok(CccCapabilities::from(provider.capabilities()))
}

// ── AEAD ─────────────────────────────────────────────────────────────────────

/// Encrypt with an AEAD algorithm.
///
/// Returns ciphertext‖tag.
pub fn ccc_aead_encrypt(
    algorithm: CccAeadAlgorithm,
    key: Vec<u8>,
    nonce: Vec<u8>,
    plaintext: Vec<u8>,
    aad: Vec<u8>,
) -> Result<Vec<u8>, CccCryptoError> {
    dbg_bridge!("ccc_aead_encrypt: pt_len={}", plaintext.len());
    let provider = default_provider()?;
    Ok(provider.encrypt_aead(algorithm.to_core(), &key, &nonce, &plaintext, &aad)?)
}

/// Decrypt with an AEAD algorithm.
///
/// Expects ciphertext‖tag as `ciphertext`.
pub fn ccc_aead_decrypt(
    algorithm: CccAeadAlgorithm,
    key: Vec<u8>,
    nonce: Vec<u8>,
    ciphertext: Vec<u8>,
    aad: Vec<u8>,
) -> Result<Vec<u8>, CccCryptoError> {
    dbg_bridge!("ccc_aead_decrypt: ct_len={}", ciphertext.len());
    let provider = default_provider()?;
    Ok(provider.decrypt_aead(algorithm.to_core(), &key, &nonce, &ciphertext, &aad)?)
}

// ── KDF ──────────────────────────────────────────────────────────────────────

/// Derive key material using a KDF.
pub fn ccc_kdf_derive(
    algorithm: CccKdfAlgorithm,
    ikm: Vec<u8>,
    salt: Vec<u8>,
    info: Vec<u8>,
    length: u32,
) -> Result<Vec<u8>, CccCryptoError> {
    dbg_bridge!("ccc_kdf_derive: length={}", length);
    let provider = default_provider()?;
    let derived = provider.derive_key(
        algorithm.to_core(),
        &ikm,
        &salt,
        &info,
        length as usize,
    )?;
    // Move out of Zeroizing wrapper — FRB will copy to Dart.
    Ok(derived.to_vec())
}

// ── MAC ──────────────────────────────────────────────────────────────────────

/// Compute a MAC tag.
pub fn ccc_mac_compute(
    algorithm: CccMacAlgorithm,
    key: Vec<u8>,
    data: Vec<u8>,
) -> Result<Vec<u8>, CccCryptoError> {
    dbg_bridge!("ccc_mac_compute: data_len={}", data.len());
    let provider = default_provider()?;
    Ok(provider.compute_mac(algorithm.to_core(), &key, &data)?)
}

/// Verify a MAC tag. Returns `true` if valid.
pub fn ccc_mac_verify(
    algorithm: CccMacAlgorithm,
    key: Vec<u8>,
    data: Vec<u8>,
    mac: Vec<u8>,
) -> Result<bool, CccCryptoError> {
    dbg_bridge!("ccc_mac_verify: data_len={}", data.len());
    let provider = default_provider()?;
    Ok(provider.verify_mac(algorithm.to_core(), &key, &data, &mac)?)
}

// ── Hash ─────────────────────────────────────────────────────────────────────

/// Compute a cryptographic hash.
pub fn ccc_hash(
    algorithm: CccHashAlgorithm,
    data: Vec<u8>,
) -> Result<Vec<u8>, CccCryptoError> {
    dbg_bridge!("ccc_hash: data_len={}", data.len());
    let provider = default_provider()?;
    Ok(provider.hash(algorithm.to_core(), &data)?)
}

// ── KEM ──────────────────────────────────────────────────────────────────────

/// Generate a KEM key pair.
pub fn ccc_kem_generate_keypair(
    algorithm: CccKemAlgorithm,
) -> Result<CccKemKeyPair, CccCryptoError> {
    dbg_bridge!("ccc_kem_generate_keypair");
    let kp = kem_provider().generate_keypair(algorithm.to_core())?;
    Ok(CccKemKeyPair::from(kp))
}

/// KEM encapsulation — produce ciphertext + shared secret from a public key.
pub fn ccc_kem_encapsulate(
    algorithm: CccKemAlgorithm,
    public_key: Vec<u8>,
) -> Result<CccKemEncapResult, CccCryptoError> {
    dbg_bridge!("ccc_kem_encapsulate");
    let result = kem_provider().encapsulate(algorithm.to_core(), &public_key)?;
    Ok(CccKemEncapResult::from(result))
}

/// KEM decapsulation — recover shared secret from ciphertext + private key.
pub fn ccc_kem_decapsulate(
    algorithm: CccKemAlgorithm,
    private_key: Vec<u8>,
    ciphertext: Vec<u8>,
) -> Result<Vec<u8>, CccCryptoError> {
    dbg_bridge!("ccc_kem_decapsulate");
    let ss = kem_provider().decapsulate(algorithm.to_core(), &private_key, &ciphertext)?;
    Ok(ss.to_vec())
}

// ── Self-test ────────────────────────────────────────────────────────────────

/// Run the provider self-test and return a structured report.
pub fn ccc_self_test() -> Result<CccSelfTestReport, CccCryptoError> {
    dbg_bridge!("ccc_self_test");
    let provider = default_provider()?;
    Ok(CccSelfTestReport::from(provider.self_test()))
}