//! The browser half of WebAuthn.
//!
//! The browser converts between the base64url wire format and ArrayBuffers itself
//! (`parse*OptionsFromJSON` and `toJSON()`), so this is a thin shim. web-sys has WebAuthn
//! bindings only behind `--cfg web_sys_unstable_apis`.

use wasm_bindgen::prelude::*;

#[wasm_bindgen(inline_js = r#"
export function passkeySupported() {
  return typeof window.PublicKeyCredential === "function"
    && typeof PublicKeyCredential.parseRequestOptionsFromJSON === "function"
    && typeof PublicKeyCredential.parseCreationOptionsFromJSON === "function";
}

export async function passkeyCreate(optionsJson) {
  const publicKey = PublicKeyCredential.parseCreationOptionsFromJSON(JSON.parse(optionsJson).publicKey);
  const cred = await navigator.credentials.create({ publicKey });
  return JSON.stringify(cred.toJSON());
}

export async function passkeyGet(optionsJson) {
  const publicKey = PublicKeyCredential.parseRequestOptionsFromJSON(JSON.parse(optionsJson).publicKey);
  const cred = await navigator.credentials.get({ publicKey });
  const json = cred.toJSON();
  // webauthn-rs wants the key present, and some browsers leave it out.
  if (json.response && !("userHandle" in json.response)) json.response.userHandle = null;
  return JSON.stringify(json);
}
"#)]
extern "C" {
    #[wasm_bindgen(js_name = passkeySupported)]
    pub fn supported() -> bool;

    #[wasm_bindgen(js_name = passkeyCreate, catch)]
    async fn js_create(options: &str) -> Result<JsValue, JsValue>;

    #[wasm_bindgen(js_name = passkeyGet, catch)]
    async fn js_get(options: &str) -> Result<JsValue, JsValue>;
}

pub async fn create(options: &str) -> Result<String, String> {
    js_create(options)
        .await
        .map_err(error_text)
        .map(|v| v.as_string().unwrap_or_default())
}

pub async fn get(options: &str) -> Result<String, String> {
    js_get(options)
        .await
        .map_err(error_text)
        .map(|v| v.as_string().unwrap_or_default())
}

/// The browser reports "cancelled" and "no matching passkey" as the same NotAllowedError.
fn error_text(e: JsValue) -> String {
    match js_sys::Reflect::get(&e, &"name".into())
        .ok()
        .and_then(|v| v.as_string())
    {
        Some(name) if name != "NotAllowedError" => {
            crate::i18n::tr(&format!("The passkey was not used ({name})."))
        }
        _ => crate::i18n::tr("The passkey was not used."),
    }
}