//! WASM bindings for relicario.
//!
//! The bridge exposes an opaque `SessionHandle` API: the master key is held
//! entirely in WASM linear memory, wrapped in `Zeroizing<[u8; 32]>`, and
//! looked up per call via a u32 handle. JS cannot read key bytes.

mod session;

use wasm_bindgen::prelude::*;

use relicario_core::{derive_master_key, imgsecret, KdfParams};

/// Handle type returned from `unlock`. Backed by a `u32`; opaque to JS.
#[wasm_bindgen]
pub struct SessionHandle(u32);

#[wasm_bindgen]
impl SessionHandle {
    #[wasm_bindgen(getter)]
    pub fn value(&self) -> u32 { self.0 }
}

#[wasm_bindgen]
pub fn unlock(
    passphrase: &str,
    image_bytes: &[u8],
    salt: &[u8],
    params_json: &str,
) -> Result<SessionHandle, JsError> {
    let params: KdfParams = serde_json::from_str(params_json)
        .map_err(|e| JsError::new(&format!("params: {e}")))?;
    let image_secret = imgsecret::extract(image_bytes)
        .map_err(|e| JsError::new(&e.to_string()))?;
    let salt_arr: &[u8; 32] = salt.try_into()
        .map_err(|_| JsError::new("salt must be exactly 32 bytes"))?;
    let master_key = derive_master_key(passphrase.as_bytes(), &image_secret, salt_arr, &params)
        .map_err(|e| JsError::new(&e.to_string()))?;
    let handle = session::insert(master_key);
    Ok(SessionHandle(handle))
}

#[wasm_bindgen]
pub fn lock(handle: &SessionHandle) -> bool {
    session::remove(handle.0)
}

// Subsequent wasm_bindgen fns added in Tasks 19-21.

use serde_wasm_bindgen::Serializer;
use relicario_core::{
    decrypt_item, decrypt_manifest, decrypt_settings,
    encrypt_item, encrypt_manifest, encrypt_settings,
    Item, Manifest, VaultSettings,
};

fn need_key(handle: &SessionHandle) -> Result<(), JsError> {
    if session::with(handle.0, |_| ()).is_some() { Ok(()) }
    else { Err(JsError::new("invalid or locked session handle")) }
}

fn js_value_for<T: serde::Serialize>(v: &T) -> Result<JsValue, JsError> {
    let ser = Serializer::new().serialize_maps_as_objects(true);
    v.serialize(&ser).map_err(|e| JsError::new(&e.to_string()))
}

#[wasm_bindgen]
pub fn manifest_decrypt(handle: &SessionHandle, encrypted: &[u8]) -> Result<JsValue, JsError> {
    need_key(handle)?;
    let out = session::with(handle.0, |k| decrypt_manifest(encrypted, k))
        .unwrap()
        .map_err(|e| JsError::new(&e.to_string()))?;
    js_value_for(&out)
}

#[wasm_bindgen]
pub fn manifest_encrypt(handle: &SessionHandle, manifest_json: &str) -> Result<Vec<u8>, JsError> {
    need_key(handle)?;
    let m: Manifest = serde_json::from_str(manifest_json)
        .map_err(|e| JsError::new(&format!("manifest json: {e}")))?;
    session::with(handle.0, |k| encrypt_manifest(&m, k))
        .unwrap()
        .map_err(|e| JsError::new(&e.to_string()))
}

#[wasm_bindgen]
pub fn item_decrypt(handle: &SessionHandle, encrypted: &[u8]) -> Result<JsValue, JsError> {
    need_key(handle)?;
    let out = session::with(handle.0, |k| decrypt_item(encrypted, k))
        .unwrap()
        .map_err(|e| JsError::new(&e.to_string()))?;
    js_value_for(&out)
}

#[wasm_bindgen]
pub fn item_encrypt(handle: &SessionHandle, item_json: &str) -> Result<Vec<u8>, JsError> {
    need_key(handle)?;
    let item: Item = serde_json::from_str(item_json)
        .map_err(|e| JsError::new(&format!("item json: {e}")))?;
    session::with(handle.0, |k| encrypt_item(&item, k))
        .unwrap()
        .map_err(|e| JsError::new(&e.to_string()))
}

#[wasm_bindgen]
pub fn settings_decrypt(handle: &SessionHandle, encrypted: &[u8]) -> Result<JsValue, JsError> {
    need_key(handle)?;
    let out = session::with(handle.0, |k| decrypt_settings(encrypted, k))
        .unwrap()
        .map_err(|e| JsError::new(&e.to_string()))?;
    js_value_for(&out)
}

#[wasm_bindgen]
pub fn settings_encrypt(handle: &SessionHandle, settings_json: &str) -> Result<Vec<u8>, JsError> {
    need_key(handle)?;
    let s: VaultSettings = serde_json::from_str(settings_json)
        .map_err(|e| JsError::new(&format!("settings json: {e}")))?;
    session::with(handle.0, |k| encrypt_settings(&s, k))
        .unwrap()
        .map_err(|e| JsError::new(&e.to_string()))
}

// ── Task 20: attachment / generator / imgsecret / ID / TOTP bridges ─────────

use relicario_core::{decrypt_attachment, encrypt_attachment, FieldId, ItemId};

#[wasm_bindgen]
pub struct EncryptedAttachment {
    aid: String,
    bytes: Vec<u8>,
}

#[wasm_bindgen]
impl EncryptedAttachment {
    #[wasm_bindgen(getter)] pub fn aid(&self) -> String { self.aid.clone() }
    #[wasm_bindgen(getter)] pub fn bytes(&self) -> Vec<u8> { self.bytes.clone() }
}

#[wasm_bindgen]
pub fn attachment_encrypt(
    handle: &SessionHandle,
    plaintext: &[u8],
    max_bytes: u64,
) -> Result<EncryptedAttachment, JsError> {
    need_key(handle)?;
    let enc = session::with(handle.0, |k| encrypt_attachment(plaintext, k, max_bytes))
        .unwrap()
        .map_err(|e| JsError::new(&e.to_string()))?;
    Ok(EncryptedAttachment { aid: enc.id.as_str().to_owned(), bytes: enc.bytes })
}

#[wasm_bindgen]
pub fn attachment_decrypt(
    handle: &SessionHandle,
    encrypted: &[u8],
) -> Result<Vec<u8>, JsError> {
    need_key(handle)?;
    let plain = session::with(handle.0, |k| decrypt_attachment(encrypted, k))
        .unwrap()
        .map_err(|e| JsError::new(&e.to_string()))?;
    Ok(plain.to_vec())
}

#[wasm_bindgen] pub fn new_item_id() -> String { ItemId::new().as_str().to_owned() }
#[wasm_bindgen] pub fn new_field_id() -> String { FieldId::new().as_str().to_owned() }

use relicario_core::{
    generate_passphrase as core_generate_passphrase,
    generate_password as core_generate_password,
    rate_passphrase as core_rate_passphrase,
    GeneratorRequest,
};

#[wasm_bindgen]
pub fn generate_password(request_json: &str) -> Result<String, JsError> {
    let req: GeneratorRequest = serde_json::from_str(request_json)
        .map_err(|e| JsError::new(&format!("generator request: {e}")))?;
    let out = core_generate_password(&req).map_err(|e| JsError::new(&e.to_string()))?;
    Ok(out.as_str().to_owned())
}

#[wasm_bindgen]
pub fn generate_passphrase(request_json: &str) -> Result<String, JsError> {
    let req: GeneratorRequest = serde_json::from_str(request_json)
        .map_err(|e| JsError::new(&format!("generator request: {e}")))?;
    let out = core_generate_passphrase(&req).map_err(|e| JsError::new(&e.to_string()))?;
    Ok(out.as_str().to_owned())
}

#[wasm_bindgen]
pub fn rate_passphrase(p: &str) -> Result<JsValue, JsError> {
    let est = core_rate_passphrase(p);
    js_value_for(&serde_json::json!({
        "score": est.score,
        "guesses_log10": est.guesses_log10,
    }))
}

#[wasm_bindgen]
pub fn extract_image_secret(image_bytes: &[u8]) -> Result<Vec<u8>, JsError> {
    let s = imgsecret::extract(image_bytes).map_err(|e| JsError::new(&e.to_string()))?;
    Ok(s.to_vec())
}

#[wasm_bindgen]
pub fn embed_image_secret(carrier: &[u8], secret: &[u8]) -> Result<Vec<u8>, JsError> {
    let s: &[u8; 32] = secret.try_into()
        .map_err(|_| JsError::new("secret must be exactly 32 bytes"))?;
    imgsecret::embed(carrier, s).map_err(|e| JsError::new(&e.to_string()))
}

use relicario_core::item_types::{TotpConfig, compute_totp_code};

#[wasm_bindgen]
pub struct TotpCode {
    code: String,
    expires_at: u64,
}

#[wasm_bindgen]
impl TotpCode {
    #[wasm_bindgen(getter)] pub fn code(&self) -> String { self.code.clone() }
    #[wasm_bindgen(getter)] pub fn expires_at(&self) -> u64 { self.expires_at }
}

#[wasm_bindgen]
pub fn totp_compute(
    config_json: &str,
    now_unix_seconds: u64,
) -> Result<TotpCode, JsError> {
    let cfg: TotpConfig = serde_json::from_str(config_json)
        .map_err(|e| JsError::new(&format!("totp config: {e}")))?;
    let code = compute_totp_code(&cfg, now_unix_seconds)
        .map_err(|e| JsError::new(&e.to_string()))?;
    let period = cfg.period_seconds as u64;
    let expires_at = ((now_unix_seconds / period) + 1) * period;
    Ok(TotpCode { code, expires_at })
}

#[cfg(test)]
mod session_tests {
    use super::*;
    use zeroize::Zeroizing;

    #[test]
    fn insert_then_remove_clears_entry() {
        session::clear();
        let h = session::insert(Zeroizing::new([0x11u8; 32]));
        assert_ne!(h, 0);
        assert!(session::remove(h));
        assert!(!session::remove(h));   // second remove false
    }

    #[test]
    fn with_yields_key_only_while_session_lives() {
        session::clear();
        let h = session::insert(Zeroizing::new([0x22u8; 32]));
        let byte = session::with(h, |k| k[0]);
        assert_eq!(byte, Some(0x22));
        session::remove(h);
        let byte = session::with(h, |k| k[0]);
        assert_eq!(byte, None);
    }

    #[test]
    fn manifest_round_trip_via_handle() {
        use relicario_core::{Manifest, decrypt_manifest};
        session::clear();
        let h = session::insert(Zeroizing::new([0x55u8; 32]));
        let handle = SessionHandle(h);
        let key = Zeroizing::new([0x55u8; 32]);
        let empty = Manifest::new();
        let bytes = manifest_encrypt(&handle, &serde_json::to_string(&empty).unwrap()).unwrap();
        assert!(!bytes.is_empty());
        // Decrypt via core directly (avoids js-sys on native).
        let parsed: Manifest = decrypt_manifest(&bytes, &key).unwrap();
        assert_eq!(parsed.items.len(), 0);
        // Random nonces mean two encryptions of the same plaintext differ.
        let bytes2 = manifest_encrypt(&handle, &serde_json::to_string(&empty).unwrap()).unwrap();
        assert_ne!(bytes, bytes2, "nonces must differ");
    }
}