kopuz 0.8.0

//! In-app anonymous PoToken minter (issue #349).
//!
//! Stands up a hidden `wry` WebView at the music.youtube.com origin (same-origin
//! so BgUtils' WAA `fetch` isn't CORS-blocked), injects BgUtils, and mints
//! content pots on demand — feeding `server::ytmusic::botguard`'s channel. No
//! external binary, no yt-dlp. Desktop (Linux/macOS/Windows): only the webview
//! attach differs per platform (GTK vbox vs raw NSView/HWND); the mint channel
//! is drained from the event-loop tick on the main thread, so there's no
//! platform-specific async runtime.
//!
//! Proven standalone in /tmp/yt-wry-minter. Tricks: same-origin page for the
//! WAA fetch, `trustedTypes.createPolicy` to `new Function` the BotGuard VM
//! past YouTube's CSP, and capturing `BG` at document-start before the page
//! clobbers `window.module`.

use std::cell::{Cell, RefCell};
use std::collections::HashMap;
use std::rc::Rc;
use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};

use dioxus::desktop::tao::dpi::{LogicalPosition, LogicalSize};
use dioxus::desktop::tao::event_loop::EventLoopWindowTarget;
use dioxus::desktop::tao::window::{Window, WindowBuilder};
use dioxus::desktop::wry::{WebView, WebViewBuilder};
use server::ytmusic::botguard::{self, MintRequest};
use tokio::sync::mpsc;

#[cfg(target_os = "linux")]
use dioxus::desktop::tao::platform::unix::WindowExtUnix;
#[cfg(target_os = "linux")]
use dioxus::desktop::wry::WebViewBuilderExtUnix;

const BGUTILS: &str = include_str!("bgutils.js");
const UA: &str = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) \
                  Chrome/131.0.0.0 Safari/537.36";

static REQ_ID: AtomicU64 = AtomicU64::new(1);
/// Set by the app when an anonymous YouTube Music server is active; the
/// event-loop handler then installs the minter on the next tick.
static WANT: AtomicBool = AtomicBool::new(false);

/// Called from the app (anon YT Music selected) to request the minter.
pub fn request() {
    WANT.store(true, Ordering::Relaxed);
}

type Pending = Rc<RefCell<HashMap<u64, tokio::sync::oneshot::Sender<Result<String, String>>>>>;

/// The live minter, kept on the main thread for the app's lifetime.
struct Minter {
    _window: Window,
    webview: WebView,
    pending: Pending,
    rx: mpsc::UnboundedReceiver<MintRequest>,
}

thread_local! {
    static INSTALLED: Cell<bool> = const { Cell::new(false) };
    static STATE: RefCell<Option<Minter>> = const { RefCell::new(None) };
}

fn init_script() -> String {
    // `PoToken.generate` does the whole BotGuard dance — VM load, snapshot, and
    // the GenerateIT WAA round-trip (jnn-pa) — on *every* call (~1 s). The
    // integrity token it negotiates is reusable for `estimatedTtlSecs` (hours)
    // and content pots are minted from it locally. So we split: negotiate the
    // integrity token + WebPoMinter once (and refresh near expiry), then per
    // track only `mintAsWebsafeString(videoId)` runs — sub-ms, no network.
    format!(
        r#"
window.module = {{ exports: {{}} }}; window.exports = window.module.exports;
// Chromium (WebView2) enforces Trusted Types on `new Function`/`eval`; the
// BotGuard VM does unwrapped `new Function(...)` internally, so a permissive
// `default` policy is needed to let those through. WebKit (Linux/macOS) ignores
// this (no enforcement). Best-effort: a pre-existing default policy throws.
try {{
  if (window.trustedTypes && window.trustedTypes.createPolicy) {{
    window.trustedTypes.createPolicy('default', {{
      createHTML: function(s) {{ return s; }},
      createScript: function(s) {{ return s; }},
      createScriptURL: function(s) {{ return s; }}
    }});
  }}
}} catch (e) {{}}
{BGUTILS}
window.__KOPUZ_BGX = (window.module && window.module.exports) || null;
window.__kopuzMinter = null;
window.__kopuzMinterExp = 0;
window.__kopuzMinting = null;
// Diagnostic side-channel (no reqId): forwards minter progress/errors to the
// Rust side so a broken minter is debuggable from logs (issue: BotGuard VM
// throwing "Function@[native code]" on some webview setups).
window.__kopuzDiag = function(m) {{ try {{ window.ipc.postMessage(JSON.stringify({{diag: '' + m}})); }} catch(e) {{}} }};

window.__kopuzEnsureMinter = function(quiet) {{
  var now = Date.now();
  if (window.__kopuzMinter && now < window.__kopuzMinterExp) return Promise.resolve(window.__kopuzMinter);
  if (window.__kopuzMinting) return window.__kopuzMinting;
  window.__kopuzMinting = (async function() {{
    var step = 'capture_bg';
    try {{
    var X = window.__KOPUZ_BGX;
    if (!X || !X.BG) throw new Error('BgUtils BG not captured (page structure changed?)');
    var BG = X.BG;
    var bgConfig = {{
      fetch: function(u, o) {{ return fetch(u, o); }},
      globalObj: window, identifier: '', requestKey: "O43z0dpjhgX20SCx4KAo"
    }};
    step = 'challenge_create';
    var ch = await BG.Challenge.create(bgConfig);
    if (!ch) throw new Error('null challenge');
    step = 'run_interpreter';
    var js = ch.interpreterJavascript && ch.interpreterJavascript.privateDoNotAccessOrElseSafeScriptWrappedValue;
    if (js) {{
      var src = js;
      if (window.trustedTypes && window.trustedTypes.createPolicy) {{
        var pol = window.trustedTypes.createPolicy('kopuz-bg', {{ createScript: function(s){{ return s; }} }});
        src = pol.createScript(js);
      }}
      new Function(src)();
    }}
    step = 'botguard_create';
    var botguard = await BG.BotGuardClient.create({{ program: ch.program, globalName: ch.globalName, globalObj: window }});
    step = 'snapshot';
    var sig = [];
    var botguardResponse = await botguard.snapshot({{ webPoSignalOutput: sig }});
    step = 'generate_it';
    var itUrl = X.buildURL('GenerateIT', bgConfig.useYouTubeAPI);
    var itResp = await bgConfig.fetch(itUrl, {{
      method: 'POST', headers: X.getHeaders(),
      body: JSON.stringify([bgConfig.requestKey, botguardResponse])
    }});
    var it = await itResp.json();
    step = 'webpominter_create';
    var itData = {{ integrityToken: it[0], estimatedTtlSecs: it[1], mintRefreshThreshold: it[2], websafeFallbackToken: it[3] }};
    var minter = await BG.WebPoMinter.create(itData, sig);
    var ttl = (itData.estimatedTtlSecs > 0) ? itData.estimatedTtlSecs : 21600;
    window.__kopuzMinter = minter;
    window.__kopuzMinterExp = Date.now() + Math.floor(ttl * 0.8) * 1000;
    window.__kopuzDiag('integrity token negotiated (ttl=' + ttl + 's)');
    return minter;
    }} catch (e) {{
      var label = quiet ? 'ensureMinter warmup failed (will retry)' : 'ensureMinter FAILED';
      window.__kopuzDiag(label + ' at step=' + step + ' :: ' + ((e && e.stack) ? e.stack : ('' + e)));
      throw e;
    }}
  }})();
  window.__kopuzMinting.then(function() {{ window.__kopuzMinting = null; }},
    function() {{ window.__kopuzMinting = null; window.__kopuzMinter = null; window.__kopuzMinterExp = 0; }});
  return window.__kopuzMinting;
}};

window.__kopuzMint = async function(videoId, reqId) {{
  function send(o) {{ o.id = reqId; try {{ window.ipc.postMessage(JSON.stringify(o)); }} catch(e) {{}} }}
  var phase = 'ensure_minter';
  try {{
    var minter = await window.__kopuzEnsureMinter();
    phase = 'mint';
    var pot = await minter.mintAsWebsafeString(videoId);
    send({{pot: (pot || '') + ''}});
  }} catch (e) {{
    window.__kopuzMinter = null; window.__kopuzMinterExp = 0;
    var stk = (e && e.stack) ? e.stack : ('' + e);
    window.__kopuzDiag('mint FAILED in phase=' + phase + ' :: ' + stk);
    send({{err: 'phase=' + phase + ': ' + stk}});
  }}
}};

// One-shot environment snapshot: whether BgUtils captured BG, Trusted-Types
// presence, the automation flag, and the UA — the usual culprits when the
// BotGuard VM behaves differently across webview builds.
setTimeout(function() {{
  var x = window.__KOPUZ_BGX;
  window.__kopuzDiag('env: bgx=' + !!x + ' BG=' + !!(x && x.BG) + ' trustedTypes=' + !!(window.trustedTypes) + ' webdriver=' + navigator.webdriver + ' ua=' + navigator.userAgent);
}}, 2000);

// Pre-warm the integrity token as soon as the origin is live, so even the
// first track doesn't pay the negotiation. Best-effort, backs off, then stops.
(function warm(n) {{
  if (!window.__KOPUZ_BGX || !window.__KOPUZ_BGX.BG) {{ if (n > 0) setTimeout(function() {{ warm(n - 1); }}, 500); return; }}
  // quiet while retries remain: the first snapshot right after page load is
  // flaky, and a self-healing attempt shouldn't read as a failure. The LAST
  // attempt (and every on-demand mint) reports loudly.
  window.__kopuzEnsureMinter(n > 0).catch(function() {{ if (n > 0) setTimeout(function() {{ warm(n - 1); }}, 2000); }});
}})(20);
"#
    )
}

/// Create the minter WebView once an anon YT Music server is active and register
/// its channel with `botguard`. Called every event-loop tick from
/// `Config::with_custom_event_handler`; no-ops until `request()` is set.
pub fn install_if_wanted<T: 'static>(target: &EventLoopWindowTarget<T>) {
    if !WANT.load(Ordering::Relaxed) {
        return;
    }
    // Only mark installed once setup actually succeeds — otherwise a transient
    // failure on the way down would wedge the minter off for the whole session.
    if INSTALLED.with(|c| c.get()) {
        return;
    }

    // Hidden, undecorated, parked off-screen — the webview runs (JS, fetch)
    // regardless of visibility. On Linux wry attaches to the window's GTK vbox
    // container (the generic raw-handle `build` isn't supported here).
    let window = match WindowBuilder::new()
        .with_title("kopuz pot minter")
        .with_inner_size(LogicalSize::new(1.0, 1.0))
        .with_position(LogicalPosition::new(-32000.0, -32000.0))
        .with_decorations(false)
        .with_visible(false)
        .build(target)
    {
        Ok(w) => w,
        Err(e) => {
            tracing::error!(error = %e, "pot-minter window build failed");
            return;
        }
    };
    let pending: Pending = Rc::new(RefCell::new(HashMap::new()));
    let pending_ipc = pending.clone();

    let builder = WebViewBuilder::new()
        .with_url("https://music.youtube.com/")
        .with_user_agent(UA)
        .with_initialization_script(init_script())
        .with_ipc_handler(move |req| {
            let body = req.into_body();
            let v: serde_json::Value = serde_json::from_str(&body).unwrap_or_default();
            // Diagnostic side-channel (no reqId): which BotGuard step failed +
            // the full JS stack, so a broken minter shows up in logs as more
            // than "Function@[native code]".
            if let Some(diag) = v.get("diag").and_then(|d| d.as_str()) {
                // Real failures at WARN; the negotiation success at INFO so a
                // boot whose first warmup attempt failed (the BotGuard
                // snapshot is flaky right after page load) visibly resolves
                // instead of ending on a scary warning; self-healing warmup
                // retries and env dumps are routine — DEBUG.
                if diag.contains("FAILED") || diag.contains("error") {
                    tracing::warn!(%diag, "pot-minter diagnostic");
                } else if diag.contains("will retry") {
                    tracing::debug!(%diag, "pot-minter diagnostic");
                } else if diag.contains("integrity token negotiated") {
                    tracing::info!(%diag, "pot-minter diagnostic");
                } else {
                    tracing::debug!(%diag, "pot-minter diagnostic");
                }
                return;
            }
            let Some(id) = v.get("id").and_then(|i| i.as_u64()) else {
                return;
            };
            let result = match v.get("pot").and_then(|p| p.as_str()) {
                Some(pot) => Ok(pot.to_string()),
                None => {
                    let err = v
                        .get("err")
                        .and_then(|e| e.as_str())
                        .unwrap_or("mint failed")
                        .to_string();
                    tracing::error!(error = %err, "pot-minter mint error");
                    Err(err)
                }
            };
            if let Some(reply) = pending_ipc.borrow_mut().remove(&id) {
                let _ = reply.send(result);
            }
        });

    // The only platform-specific bit: Linux wry attaches to the window's GTK
    // vbox; macOS/Windows take the raw NSView/HWND via the generic `build`.
    #[cfg(target_os = "linux")]
    let built = match window.default_vbox() {
        Some(vbox) => builder.build_gtk(vbox),
        None => {
            tracing::error!("pot-minter: no GTK vbox on window");
            return;
        }
    };
    #[cfg(not(target_os = "linux"))]
    let built = builder.build(&window);

    let webview = match built {
        Ok(w) => w,
        Err(e) => {
            tracing::error!(error = %e, "pot-minter webview build failed");
            return;
        }
    };

    let (tx, rx) = mpsc::unbounded_channel::<MintRequest>();
    if botguard::set_minter(tx).is_err() {
        tracing::warn!("pot-minter already registered");
    }

    STATE.with(|s| {
        *s.borrow_mut() = Some(Minter {
            _window: window,
            webview,
            pending,
            rx,
        });
    });
    INSTALLED.with(|c| c.set(true));
    tracing::info!("pot-minter installed (anon PoToken minting via webview)");
}

/// Drain queued mint requests and dispatch each to the webview. Called every
/// event-loop tick from the custom event handler — runs on the main thread on
/// all platforms, replacing the old Linux-only glib async drain.
pub fn pump() {
    STATE.with(|s| {
        let mut guard = s.borrow_mut();
        let Some(state) = guard.as_mut() else {
            return;
        };
        while let Ok(req) = state.rx.try_recv() {
            let id = REQ_ID.fetch_add(1, Ordering::Relaxed);
            state.pending.borrow_mut().insert(id, req.reply);
            let vid: String = req
                .video_id
                .chars()
                .filter(|c| c.is_ascii_alphanumeric() || *c == '_' || *c == '-')
                .collect();
            let _ = state.webview.evaluate_script(&format!(
                "window.__kopuzMint && window.__kopuzMint('{vid}', {id})"
            ));
        }
    });
}