tauri_plugin_devtools_app/desktop/

mod.rs

#![allow(clippy::items_after_statements, clippy::used_underscore_binding)]

use std::{
    collections::HashMap,
    fmt::Display,
    net::{IpAddr, Ipv4Addr, SocketAddr, TcpListener},
    process::Child,
    sync::{
        atomic::{AtomicBool, Ordering},
        Arc, Mutex,
    },
    time::Duration,
};

use colored::Colorize;
use include_dir::{include_dir, Dir};
use serde::{Deserialize, Serialize, Serializer};
use serialize_to_javascript::{default_template, DefaultTemplate, Template};
use tauri::{
    ipc::CapabilityBuilder, menu::ContextMenu, AppHandle, Emitter, Listener, LogicalSize, Manager,
    RunEvent, Runtime, State, Url, WindowEvent,
};
use tauri::{
    PhysicalPosition, PhysicalSize, Webview, WebviewBuilder, WebviewUrl, Window, WindowBuilder,
};
use tauri_plugin_devtools::{ConnectionInfo, Devtools};

mod devtools_ipc;
mod utils;

static AUTH_DIST: Dir = include_dir!("$CARGO_MANIFEST_DIR/auth-dist");

const STANDALONE_DEVTOOLS_WINDOW_LABEL_PREFIX: &str = "devtools-";
const DEVTOOLS_WEBVIEW_LABEL_PREFIX: &str = "tauri-plugin-devtools-";
const SPLASHSCREEN_LABEL_PREFIX: &str = "devtools-splashscreen-";
const SPLASHSCREEN_ASSETS_URI_SCHEME: &str = "devtools-app";

const RELOAD_MENU_ID: &str = "devtools-app-menu-reload";
#[cfg(any(debug_assertions, feature = "context-menu-inspector"))]
const INSPECT_MENU_ID: &str = "devtools-app-menu-inspect";
const OPEN_DEVTOOLS_MENU_ID: &str = "devtools-app-menu-open-devtools";

const SPLASHSCREEN_TIMEOUT: Duration = Duration::from_secs(2);

const LOCAL_DEV: bool = option_env!("__DEVTOOLS_LOCAL_DEVELOPMENT").is_some();

#[derive(Debug, thiserror::Error)]
pub enum Error {
    #[error(transparent)]
    Tauri(#[from] tauri::Error),
    #[error("failed to read stdout: {0}")]
    ReadStdout(std::io::Error),
    #[error("failed to start devtools")]
    FailedToStartDevtools,
    #[error("IO error: {0}")]
    Io(#[from] std::io::Error),
}

type Result<T> = std::result::Result<T, Error>;

/// Builds the URL (scheme + authority) a registered custom protocol is served from.
type CustomSchemeUrlFn = Box<dyn Fn(&str) -> String + Send + Sync>;

/// URL the runtime serves a custom protocol from, e.g. `{scheme}://localhost` on wry
/// or `http://{scheme}.localhost` on CEF and on Windows.
///
/// `custom_scheme_url` is defined on the `tauri_runtime::RuntimeHandle` supertrait, which tauri does not
/// re-export; a bound on the wrapper trait still brings it into scope.
fn runtime_custom_scheme_url<H: tauri::RuntimeHandle>(handle: &H, scheme: &str) -> String {
    handle.custom_scheme_url(scheme, false)
}

impl Serialize for Error {
    fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_str(self.to_string().as_ref())
    }
}

struct AppProcess {
    server_port: Mutex<u16>,
    child: Child,
    outgoing_message_tx: tokio::sync::mpsc::Sender<devtools_ipc::Message>,
    authenticated: Arc<AtomicBool>,
}

impl AppProcess {
    fn server_port(&self) -> u16 {
        *self.server_port.lock().unwrap()
    }

    fn dashboard_url(&self, connection: &ConnectionInfo) -> Url {
        let host = format!("http://localhost:{}", self.server_port());
        let url = format!("{host}/dash/{}/{}/", connection.host, connection.port);
        url.parse().unwrap()
    }
}

struct DevtoolsApp {
    auth_protocol: String,
    /// Custom scheme URL override, see [`Builder::custom_scheme_url`]. `None` asks the runtime.
    custom_scheme_url: Option<CustomSchemeUrlFn>,
    app_process: Mutex<Option<AppProcess>>,
    children: Mutex<Vec<Child>>,
    // maps a window label to its devtools webview state
    webviews: Mutex<HashMap<String, DevtoolsWebviewState>>,
    // maps a standalone window label to its parent window
    standalone_window_parents: Mutex<HashMap<String, String>>,
}

impl Default for DevtoolsApp {
    fn default() -> Self {
        Self {
            auth_protocol: String::new(),
            custom_scheme_url: None,
            app_process: Mutex::new(None),
            children: Mutex::new(Vec::new()),
            webviews: Mutex::new(HashMap::new()),
            standalone_window_parents: Mutex::new(HashMap::new()),
        }
    }
}

struct DevtoolsWebviewState {
    opened: AtomicBool,
    display_mode: Mutex<DisplayMode>,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Deserialize)]
enum DisplayMode {
    EmbeddedBottom,
    EmbeddedLeft,
    EmbeddedRight,
    Standalone,
}

impl Default for DisplayMode {
    #[cfg(target_os = "linux")]
    fn default() -> Self {
        Self::Standalone
    }

    #[cfg(not(target_os = "linux"))]
    fn default() -> Self {
        Self::EmbeddedBottom
    }
}

impl Display for DisplayMode {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::EmbeddedBottom => write!(f, "EmbeddedBottom"),
            Self::EmbeddedLeft => write!(f, "EmbeddedLeft"),
            Self::EmbeddedRight => write!(f, "EmbeddedRight"),
            Self::Standalone => write!(f, "Standalone"),
        }
    }
}

/// Native context menu and the webview that last opened it (only one menu is visible at a time).
struct DevtoolsContextMenu<R: Runtime> {
    menu: tauri::menu::Menu<R>,
    source_webview: Mutex<Option<Webview<R>>>,
}

fn port_is_available(addr: Ipv4Addr, port: u16) -> bool {
    TcpListener::bind(SocketAddr::new(IpAddr::V4(addr), port)).is_ok()
}

impl DevtoolsApp {
    /// URL a registered custom protocol is served from, used for the pre-auth devtools UI and the splashscreen.
    fn scheme_url<R: Runtime>(&self, app: &AppHandle<R>, protocol: &str) -> String {
        match &self.custom_scheme_url {
            Some(custom_scheme_url) => custom_scheme_url(protocol),
            None => runtime_custom_scheme_url(app.runtime_handle(), protocol),
        }
    }

    fn auth_login_url<R: Runtime>(&self, app: &AppHandle<R>) -> String {
        self.scheme_url(app, &self.auth_protocol)
    }

    async fn start<R: Runtime>(&self, window: &Window<R>) -> Result<()> {
        let child = utils::spawn_devtools_app()?;

        let authenticated = Arc::new(AtomicBool::new(false));

        let (outgoing_message_tx, outgoing_message_rx) = tokio::sync::mpsc::channel(1);

        let app_process = AppProcess {
            server_port: Mutex::new(0),
            child,
            outgoing_message_tx,
            authenticated: authenticated.clone(),
        };

        self.app_process.lock().unwrap().replace(app_process);

        let (ready_tx, ready_rx) = std::sync::mpsc::channel();
        let (mut got_port, mut got_auth, mut ready) = (false, false, false);
        let window = window.clone();

        devtools_ipc::start(outgoing_message_rx, move |event| match event {
            devtools_ipc::DevtoolsMessage::ServerPort(port) => {
                if let Some(app_process) =
                    &*window.state::<DevtoolsApp>().app_process.lock().unwrap()
                {
                    let mut server_port = app_process.server_port.lock().unwrap();
                    if *server_port == 0 {
                        *server_port = port;
                        window.state::<Devtools>().server_handle.allow_origin(
                            http::HeaderValue::from_str(&format!("http://localhost:{port}"))
                                .unwrap(),
                        );
                    }

                    got_port = true;
                    if !ready {
                        ready = got_port && got_auth;
                        if ready {
                            ready_tx.send(()).unwrap();
                        }
                    }
                }
            }
            devtools_ipc::DevtoolsMessage::Authenticated(auth) => {
                authenticated.store(auth, Ordering::Relaxed);

                if let Some(devtools_webview) = devtools_webview(&window) {
                    if let Some(app_process) =
                        &*window.state::<DevtoolsApp>().app_process.lock().unwrap()
                    {
                        let _ = devtools_webview.window().set_focus();
                        let _ = devtools_webview.navigate(if auth {
                            app_process.dashboard_url(&window.state::<Devtools>().connection)
                        } else {
                            window
                                .state::<DevtoolsApp>()
                                .auth_login_url(window.app_handle())
                                .parse()
                                .unwrap()
                        });
                    }
                }

                got_auth = true;
                if !ready {
                    ready = got_port && got_auth;
                    if ready {
                        ready_tx.send(()).unwrap();
                    }
                }
            }
            devtools_ipc::DevtoolsMessage::AuthError(error) => {
                if let Some(devtools_webview) = devtools_webview(&window) {
                    let _ = devtools_webview.emit("auth-error", &error);
                }
            }
        })
        .await?;

        ready_rx.recv().unwrap();

        Ok(())
    }
}

fn create_devtools_webview<R: Runtime>(
    window: &Window<R>,
    display_mode: DisplayMode,
    label: &str,
    url: WebviewUrl,
    position: PhysicalPosition<u32>,
    size: PhysicalSize<u32>,
) -> Result<Webview<R>> {
    let webview_builder = WebviewBuilder::new(label, url)
        .initialization_script(format!(
            "window.__DEVTOOLS_DISPLAY_MODE__ = '{display_mode}'",
        ))
        .auto_resize();

    let webview = window.add_child(webview_builder, position, size)?;

    Ok(webview)
}

fn app_webview_bounds(
    window_size: PhysicalSize<u32>,
    devtools_webview_size: PhysicalSize<u32>,
    mode: DisplayMode,
) -> (PhysicalSize<u32>, PhysicalPosition<u32>) {
    match mode {
        DisplayMode::EmbeddedBottom => (
            PhysicalSize::new(
                window_size.width,
                window_size.height - devtools_webview_size.height,
            ),
            PhysicalPosition::new(0, 0),
        ),
        DisplayMode::EmbeddedLeft => (
            PhysicalSize::new(
                window_size.width - devtools_webview_size.width,
                window_size.height,
            ),
            PhysicalPosition::new(devtools_webview_size.width, 0),
        ),
        DisplayMode::EmbeddedRight => (
            PhysicalSize::new(
                window_size.width - devtools_webview_size.width,
                window_size.height,
            ),
            PhysicalPosition::new(0, 0),
        ),
        DisplayMode::Standalone => unimplemented!(),
    }
}

fn devtools_webview_bounds(
    app_webview_size: PhysicalSize<u32>,
    mode: DisplayMode,
) -> (PhysicalSize<u32>, PhysicalPosition<u32>) {
    match mode {
        DisplayMode::EmbeddedBottom => {
            let height = app_webview_size.height / 3;
            let size = PhysicalSize::new(app_webview_size.width, height);
            let position = PhysicalPosition::new(0, app_webview_size.height - height);
            (size, position)
        }
        DisplayMode::EmbeddedLeft => {
            let width = app_webview_size.width / 3;
            let size = PhysicalSize::new(width, app_webview_size.height);
            let position = PhysicalPosition::new(0, 0);
            (size, position)
        }
        DisplayMode::EmbeddedRight => {
            let width = app_webview_size.width / 3;
            let size = PhysicalSize::new(width, app_webview_size.height);
            let position = PhysicalPosition::new(app_webview_size.width - width, 0);
            (size, position)
        }
        DisplayMode::Standalone => unimplemented!(),
    }
}

fn app_webview<R: Runtime>(window: &Window<R>) -> Option<Webview<R>> {
    window.webviews().into_iter().find(|w| {
        !w.label().starts_with(DEVTOOLS_WEBVIEW_LABEL_PREFIX)
            && !w.label().starts_with(SPLASHSCREEN_LABEL_PREFIX)
    })
}

fn devtools_webview<R: Runtime>(window: &Window<R>) -> Option<Webview<R>> {
    window
        .webviews()
        .into_iter()
        .find(|w| w.label().starts_with(DEVTOOLS_WEBVIEW_LABEL_PREFIX))
}

fn create_standalone_window<R: Runtime, M: Manager<R>>(
    manager: &M,
    window_size: LogicalSize<f64>,
    visible: bool,
) -> tauri::Result<Window<R>> {
    WindowBuilder::new(
        manager,
        format!(
            "{STANDALONE_DEVTOOLS_WINDOW_LABEL_PREFIX}{}",
            rand::random::<usize>()
        ),
    )
    .inner_size(window_size.width, window_size.height)
    .title("CrabNebula DevTools Desktop")
    .visible(visible)
    .build()
}

// initialize the devtools webview for the first time on the given window
#[allow(clippy::too_many_arguments)]
fn initialize_devtools_webview<R: Runtime>(
    // the window that requested the webview to be created
    parent_window: &Window<R>,
    // the window where we should inject the webview
    devtools_window: &Window<R>,
    // the application webview if we found one
    app_webview: Option<&Webview<R>>,
    // splashscreen if we're using one (when the devtools is already ready, we do not use it)
    splashscreen: Option<Webview<R>>,
    app_process: &AppProcess,
    display_mode: DisplayMode,
    // where we should inject the webview
    position: PhysicalPosition<u32>,
    // webview size
    size: PhysicalSize<u32>,
) -> Result<()> {
    let devtools_app = parent_window.state::<DevtoolsApp>();
    let login_url = devtools_app.auth_login_url(parent_window.app_handle());

    let dashboard_url = app_process.dashboard_url(&parent_window.state::<Devtools>().connection);
    let dashboard_capability_remote = format!(
        "{}://{}:{}/**",
        dashboard_url.scheme(),
        dashboard_url.host_str().unwrap(),
        dashboard_url.port().unwrap(),
    );

    let devtools_url = if app_process.authenticated.load(Ordering::Relaxed) {
        dashboard_url
    } else {
        login_url.parse().unwrap()
    };

    // adds the permissions required by the devtools frontend
    parent_window.add_capability(
        CapabilityBuilder::new("devtools-app-plugin-runtime")
            .window("*")
            .webview(format!("{DEVTOOLS_WEBVIEW_LABEL_PREFIX}*"))
            .remote(dashboard_capability_remote)
            .remote(login_url)
            .permission("core:event:default")
            .permission("devtools-app:default"),
    )?;

    // on embedded mode we should resize the app webview
    if display_mode != DisplayMode::Standalone {
        if let Some(w) = &app_webview {
            let window_size = parent_window.inner_size()?;
            let (app_webview_size, app_webview_position) =
                app_webview_bounds(window_size, size, display_mode);
            w.set_size(app_webview_size)?;
            w.set_position(app_webview_position)?;
        }
    }

    inject_devtools_webview(
        devtools_window,
        display_mode,
        devtools_url,
        splashscreen,
        position,
        size,
        app_process,
    )?;

    Ok(())
}

// actually create the devtools webview in the given window
fn inject_devtools_webview<R: Runtime>(
    // the window where we should inject the devtools webview
    window: &Window<R>,
    // the display mode
    display_mode: DisplayMode,
    // URL to load
    url: Url,
    // if there's a splashscreen running, we should load the devtools as initially hidden
    // and close the splashscreen when it is ready
    splashscreen: Option<Webview<R>>,
    // where we should inject the webview
    position: PhysicalPosition<u32>,
    // webview size
    size: PhysicalSize<u32>,
    // application process instance
    app_process: &AppProcess,
) -> Result<()> {
    let devtools_webview = if splashscreen.is_some() {
        // on Linux we use a hidden window to initialize the webview
        // because the webview sizing is buggy with the default method
        #[cfg(target_os = "linux")]
        {
            let hidden_window = create_standalone_window(
                window,
                window.inner_size()?.to_logical(window.scale_factor()?),
                false,
            )?;
            create_devtools_webview(
                &hidden_window,
                display_mode,
                &format!("{DEVTOOLS_WEBVIEW_LABEL_PREFIX}{}", rand::random::<usize>()),
                WebviewUrl::External(url),
                PhysicalPosition::new(0, 0),
                hidden_window.inner_size()?,
            )?
        }
        // use a "hidden webview" to initialize the devtools (a webview with size 0,0)
        #[cfg(not(target_os = "linux"))]
        create_devtools_webview(
            window,
            display_mode,
            &format!("{DEVTOOLS_WEBVIEW_LABEL_PREFIX}{}", rand::random::<usize>()),
            WebviewUrl::External(url),
            PhysicalPosition::new(0, 0),
            PhysicalSize::new(0, 0),
        )?
    } else {
        create_devtools_webview(
            window,
            display_mode,
            &format!("{DEVTOOLS_WEBVIEW_LABEL_PREFIX}{}", rand::random::<usize>()),
            WebviewUrl::External(url),
            position,
            size,
        )?
    };

    let window_ = window.clone();
    devtools_webview.listen("disconnect", move |_event| {
        let _ = hide_embedded_devtools(&window_);
        window_
            .state::<DevtoolsApp>()
            .webviews
            .lock()
            .unwrap()
            .get(window_.label())
            .unwrap()
            .opened
            .store(false, Ordering::Relaxed);
    });

    let listener_tx = app_process.outgoing_message_tx.clone();
    devtools_webview.listen("login", move |_event| {
        let spawn_tx = listener_tx.clone();
        tauri::async_runtime::spawn(async move {
            if let Err(error) = spawn_tx.send(devtools_ipc::Message::Login).await {
                eprintln!("failed sending login message: {error}");
            }
        });
    });

    let close_splashscreen =
        move |splashscreen_label: &str, app_window: &Window<R>, devtools_webview: &Webview<R>| {
            if let Some(splashscreen) = app_window.app_handle().get_webview(splashscreen_label) {
                let _ = splashscreen.close();

                // webview on Linux was initialized on a separate hidden window,
                // so let's reparent and close that window
                #[cfg(target_os = "linux")]
                {
                    let devtools_window = devtools_webview.window();
                    let _ = devtools_webview.reparent(app_window);
                    let _ = devtools_window.close();
                }

                // webview was created with size 0,0 at position 0,0
                // so we must set the actual values now
                #[cfg(not(target_os = "linux"))]
                {
                    let _ = devtools_webview.set_size(size);
                    let _ = devtools_webview.set_position(position);
                }
            }
        };

    if let Some(splashscreen) = splashscreen {
        let window_ = window.clone();
        let splashscreen_label = splashscreen.label().to_string();
        let devtools_webview_ = devtools_webview.clone();
        devtools_webview
            .clone()
            .once("state-changed", move |_event| {
                close_splashscreen(&splashscreen_label, &window_, &devtools_webview_);
            });

        // splashscreen timeout in case some weird error happens in the UI and the state-changed event is not fired
        let window_ = window.clone();
        let splashscreen_label = splashscreen.label().to_string();
        tauri::async_runtime::spawn(async move {
            tokio::time::sleep(SPLASHSCREEN_TIMEOUT).await;
            close_splashscreen(&splashscreen_label, &window_, &devtools_webview);
        });
    }

    Ok(())
}

// returns a bool indicating whether it was restored or not
fn restore_embedded_devtools_webview_if_exists<R: Runtime>(
    window: &Window<R>,
    display_mode: DisplayMode,
) -> Result<bool> {
    if let Some(w) = devtools_webview(window) {
        let app_webview = app_webview(window);
        let app_webview_size = if let Some(w) = &app_webview {
            w.size()?
        } else {
            window.inner_size()?
        };

        let (size, position) = devtools_webview_bounds(app_webview_size, display_mode);
        w.set_size(size)?;
        w.set_position(position)?;

        if display_mode != DisplayMode::Standalone {
            if let Some(w) = &app_webview {
                let window_size = window.inner_size()?;
                let (app_webview_size, app_webview_position) =
                    app_webview_bounds(window_size, size, display_mode);
                w.set_size(app_webview_size)?;
                w.set_position(app_webview_position)?;
            }
        }

        Ok(true)
    } else {
        Ok(false)
    }
}

fn hide_embedded_devtools<R: Runtime>(window: &Window<R>) -> Result<()> {
    for w in window.webviews().into_iter().filter(|w| {
        w.label().starts_with(DEVTOOLS_WEBVIEW_LABEL_PREFIX)
            || w.label().starts_with(SPLASHSCREEN_LABEL_PREFIX)
    }) {
        if let Some(w) = app_webview(window) {
            let size = window.inner_size()?;
            w.set_size(size)?;
            w.set_position(PhysicalPosition::new(0, 0))?;
        }

        if w.label().starts_with(SPLASHSCREEN_LABEL_PREFIX) {
            w.close()?;
        } else {
            w.set_size(PhysicalSize::new(0, 0))?;
        }
    }
    Ok(())
}

#[tauri::command]
async fn set_display_mode<R: tauri::Runtime>(
    app: AppHandle<R>,
    window: Window<R>,
    webview: Webview<R>,
    devtools_app: tauri::State<'_, DevtoolsApp>,
    mode: DisplayMode,
) -> Result<()> {
    let devtools_window = if window
        .label()
        .starts_with(STANDALONE_DEVTOOLS_WINDOW_LABEL_PREFIX)
    {
        let parent_label = devtools_app
            .standalone_window_parents
            .lock()
            .unwrap()
            .get(window.label())
            .unwrap()
            .clone();
        if let Some(w) = app.get_window(&parent_label) {
            w
        } else {
            return Ok(());
        }
    } else {
        window.clone()
    };

    if let Some(webviews) = devtools_app
        .webviews
        .lock()
        .unwrap()
        .get(devtools_window.label())
    {
        let current_display_mode = *webviews.display_mode.lock().unwrap();

        if current_display_mode != mode {
            if current_display_mode == DisplayMode::Standalone {
                webview.reparent(&devtools_window)?;
                webview.set_size(PhysicalSize::new(0, 0))?;
                window.close()?;
            } else {
                hide_embedded_devtools(&window)?;
            }

            if mode == DisplayMode::Standalone {
                let standalone_window =
                    create_standalone_window(&app, LogicalSize::new(800., 600.), true)?;

                devtools_app
                    .standalone_window_parents
                    .lock()
                    .unwrap()
                    .insert(
                        standalone_window.label().to_string(),
                        window.label().to_string(),
                    );

                let window_size = standalone_window.inner_size()?;

                webview.reparent(&standalone_window)?;
                webview.set_size(window_size)?;
                webview.set_position(PhysicalPosition::new(0, 0))?;
            } else {
                restore_embedded_devtools_webview_if_exists(&devtools_window, mode)?;
            }

            webview.eval(format!(
            "window.__DEVTOOLS_DISPLAY_MODE__ = '{mode}'; if (window.__ON_DEVTOOLS_DISPLAY_MODE_CHANGE__) {{ window.__ON_DEVTOOLS_DISPLAY_MODE_CHANGE__() }}",
        ))?;

            *webviews.display_mode.lock().unwrap() = mode;
        }
    }

    Ok(())
}

#[allow(clippy::too_many_lines)]
#[tauri::command]
async fn toggle<R: tauri::Runtime>(
    window: Window<R>,
    devtools_app: tauri::State<'_, DevtoolsApp>,
) -> Result<()> {
    // TODO: browser behavior is a little different, when you're on a standalone inspector window
    // and press `ctrl+shift+i` you always get a new window, but that one cannot change its display mode
    if window
        .label()
        .starts_with(STANDALONE_DEVTOOLS_WINDOW_LABEL_PREFIX)
    {
        return Ok(());
    }

    let (opened, display_mode) = {
        let mut webviews = devtools_app.webviews.lock().unwrap();
        if let Some(state) = webviews.get(window.label()) {
            (
                state.opened.load(Ordering::Relaxed),
                *state.display_mode.lock().unwrap(),
            )
        } else {
            let opened = false;
            let display_mode = DisplayMode::default();

            webviews.insert(
                window.label().to_string(),
                DevtoolsWebviewState {
                    opened: AtomicBool::new(opened),
                    display_mode: Mutex::new(display_mode),
                },
            );

            (opened, display_mode)
        }
    };

    let (is_app_running, is_devtools_ready) =
        if let Some(app_process) = &*devtools_app.app_process.lock().unwrap() {
            (
                true,
                !port_is_available(Ipv4Addr::LOCALHOST, app_process.server_port()),
            )
        } else {
            (false, false)
        };

    let app_webview = app_webview(&window);

    let (devtools_window, size, position) = match display_mode {
        DisplayMode::Standalone => {
            let size = PhysicalSize::new(800, 600);
            let window_size = size.to_logical(window.scale_factor()?);
            let standalone_window = create_standalone_window(&window, window_size, true)?;

            window
                .state::<DevtoolsApp>()
                .standalone_window_parents
                .lock()
                .unwrap()
                .insert(
                    standalone_window.label().to_string(),
                    window.label().to_string(),
                );

            (standalone_window, size, PhysicalPosition::new(0, 0))
        }
        mode => {
            let app_webview_size = if let Some(w) = &app_webview {
                w.size()?
            } else {
                window.inner_size()?
            };

            let (size, position) = devtools_webview_bounds(app_webview_size, mode);
            (window.clone(), size, position)
        }
    };

    let splashscreen = if is_devtools_ready {
        None
    } else {
        let splashscreen: Webview<_> = create_devtools_webview(
            &devtools_window,
            display_mode,
            &format!("{SPLASHSCREEN_LABEL_PREFIX}-{}", rand::random::<usize>()),
            WebviewUrl::CustomProtocol(
                devtools_app
                    .scheme_url(window.app_handle(), SPLASHSCREEN_ASSETS_URI_SCHEME)
                    .parse()
                    .unwrap(),
            ),
            position,
            size,
        )?;

        Some(splashscreen)
    };

    if !is_app_running {
        devtools_app.start(&window).await?;
    }

    if display_mode == DisplayMode::Standalone {
        let app_process_guard = devtools_app.app_process.lock().unwrap();
        let app_process = app_process_guard.as_ref().unwrap();
        initialize_devtools_webview(
            &window,
            &devtools_window,
            app_webview.as_ref(),
            splashscreen,
            app_process,
            display_mode,
            position,
            size,
        )?;
    } else if opened {
        hide_embedded_devtools(&window)?;
    } else if !restore_embedded_devtools_webview_if_exists(&window, display_mode)? {
        let app_process_guard = devtools_app.app_process.lock().unwrap();
        let app_process = app_process_guard.as_ref().unwrap();
        initialize_devtools_webview(
            &window,
            &devtools_window,
            app_webview.as_ref(),
            splashscreen,
            app_process,
            display_mode,
            position,
            size,
        )?;
    }

    devtools_app
        .webviews
        .lock()
        .unwrap()
        .get(window.label())
        .unwrap()
        .opened
        .store(!opened, Ordering::Relaxed);

    Ok(())
}

#[tauri::command]
async fn show_context_menu<R: Runtime>(
    window: Window<R>,
    webview: Webview<R>,
    context_menu: State<'_, DevtoolsContextMenu<R>>,
) -> tauri::Result<()> {
    *context_menu.source_webview.lock().unwrap() = Some(webview);
    context_menu.menu.popup(window)?;
    Ok(())
}

fn setup_desktop_app_dev(devtools_app: &DevtoolsApp) {
    // this crate lives in the `crates/v3` workspace; the desktop app and web client are in the root workspace
    let repo_root = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("../../../..");

    if port_is_available(Ipv4Addr::LOCALHOST, 5173) {
        #[cfg(windows)]
        let mut command = {
            let mut cmd = std::process::Command::new("powershell");
            cmd.arg("pnpm");
            cmd
        };
        #[cfg(not(windows))]
        let mut command = std::process::Command::new("pnpm");
        // web client is not running, let's do it
        devtools_app.children.lock().unwrap().push(
            command
                .arg("dev")
                .current_dir(repo_root.join("clients/web"))
                .spawn()
                .unwrap(),
        );
    }
    // the Tauri v3 example is a standalone workspace, so `-p desktop` must be resolved against the root one
    std::process::Command::new("cargo")
        .args(["build", "-p", "desktop", "--manifest-path"])
        .arg(repo_root.join("Cargo.toml"))
        .spawn()
        .unwrap()
        .wait()
        .unwrap();
}

/// Builder for the devtools-app plugin.
///
/// [`init`] is equivalent to `Builder::new().build()`.
///
/// The [`custom_scheme_url`](Builder::custom_scheme_url) closure receives a registered
/// custom-protocol name (e.g. `isolation-…`) and returns the URL it is served from, which is used
/// for the pre-auth devtools UI and the splashscreen. By default that URL comes from the webview runtime
/// (`{scheme}://localhost` on wry, `http://{scheme}.localhost` on CEF and on Windows), so it only needs
/// to be set for runtimes that serve custom protocols somewhere else than they report.
#[derive(Default)]
pub struct Builder {
    custom_scheme_url: Option<CustomSchemeUrlFn>,
}

impl Builder {
    #[must_use]
    pub fn new() -> Self {
        Self::default()
    }

    /// Overrides the URL custom protocols are served from instead of asking the webview runtime.
    #[must_use]
    pub fn custom_scheme_url<F>(mut self, f: F) -> Self
    where
        F: Fn(&str) -> String + Send + Sync + 'static,
    {
        self.custom_scheme_url = Some(Box::new(f));
        self
    }

    /// Builds the plugin (same as [`init`] when using default options).
    #[allow(clippy::missing_panics_doc)]
    #[must_use]
    pub fn build<R: Runtime>(self) -> tauri::plugin::TauriPlugin<R> {
        let auth_protocol = format!("isolation-{}", uuid::Uuid::new_v4());

        let devtools_app = DevtoolsApp {
            custom_scheme_url: self.custom_scheme_url,
            auth_protocol: auth_protocol.clone(),
            ..Default::default()
        };

        // force desktop app to be built on development
        if LOCAL_DEV {
            setup_desktop_app_dev(&devtools_app);
        }

        let mut printed_link = false;

        #[allow(unused_mut)]
        let mut builder = tauri::plugin::Builder::new("devtools-app")
            .register_uri_scheme_protocol(SPLASHSCREEN_ASSETS_URI_SCHEME, |_app, _request| {
                tauri::http::Response::builder()
                    .header("Content-Type", "text/html")
                    .body(include_bytes!("../../assets/splashscreen.html").to_vec())
                    .unwrap()
            })
            .register_uri_scheme_protocol(&auth_protocol, |_app, request| {
                auth_protocol_handler(&request)
            })
            .setup(|app, _api| {
                app.manage(devtools_app);
                app.add_capability(include_str!("../../capabilities/app.json"))?;

                app.manage(DevtoolsContextMenu {
                    menu: create_context_menu(app)?,
                    source_webview: Mutex::new(None),
                });

                Ok(())
            })
            .on_window_ready(move |window| {
                if !printed_link {
                    print_link(&window.state::<Devtools>().connection);
                    printed_link = true;
                }
                window.on_menu_event(|window, event| on_menu_event(window, &event));
            })
            .on_event(|app, event| match event {
                RunEvent::Exit => {
                    let devtools = app.state::<DevtoolsApp>();

                    let mut children = std::mem::take(&mut *devtools.children.lock().unwrap());
                    for c in &mut children {
                        kill_child_recursively(c.id());
                        let _ = c.kill();
                    }

                    let _ = devtools.app_process.lock().unwrap().take().map(|mut p| {
                        kill_child_recursively(p.child.id());
                        let _ = p.child.kill();
                    });
                }
                RunEvent::WindowEvent {
                    label,
                    event: WindowEvent::Destroyed,
                    ..
                } => {
                    if let Some(standalone_window) = app
                        .state::<DevtoolsApp>()
                        .standalone_window_parents
                        .lock()
                        .unwrap()
                        .iter()
                        .find(|(_standalone_label, parent_label)| parent_label == &label)
                        .and_then(|(standalone_label, _parent_label)| {
                            app.get_window(standalone_label)
                        })
                    {
                        let _ = standalone_window.close();
                    }
                }
                _ => (),
            });

        #[derive(Template)]
        #[default_template("../../scripts/init.js")]
        struct InitJavascript<'a> {
            os_name: &'a str,
        }

        let js_init_script = InitJavascript {
            os_name: std::env::consts::OS,
        }
        .render_default(&serialize_to_javascript::Options::default())
        .unwrap()
        .into_string();

        builder = builder
            .initialization_script(js_init_script)
            .invoke_handler(tauri::generate_handler![
                toggle,
                set_display_mode,
                show_context_menu
            ]);

        builder.build()
    }
}

/// Initializes the Tauri plugin (same as `Builder::new().build()`).
///
/// For options such as a custom pre-auth login URL, use [`Builder`].
#[allow(clippy::missing_panics_doc)]
#[must_use]
pub fn init<R: Runtime>() -> tauri::plugin::TauriPlugin<R> {
    Builder::new().build()
}

fn create_context_menu<R: Runtime>(app: &AppHandle<R>) -> tauri::Result<tauri::menu::Menu<R>> {
    let reload =
        tauri::menu::MenuItem::with_id(app, RELOAD_MENU_ID, "Reload", true, Option::<&str>::None)?;

    #[cfg(any(debug_assertions, feature = "context-menu-inspector"))]
    let inspect = tauri::menu::MenuItem::with_id(
        app,
        INSPECT_MENU_ID,
        "Inspect",
        true,
        Option::<&str>::None,
    )?;

    let open_devtools = tauri::menu::MenuItem::with_id(
        app,
        OPEN_DEVTOOLS_MENU_ID,
        "Open Devtools",
        true,
        Option::<&str>::None,
    )?;
    let context_menu = tauri::menu::Menu::with_items(
        app,
        &[
            &reload,
            #[cfg(any(debug_assertions, feature = "context-menu-inspector"))]
            &inspect,
            &open_devtools,
        ],
    )?;

    Ok(context_menu)
}

fn auth_protocol_handler(
    request: &tauri::http::Request<Vec<u8>>,
) -> tauri::http::Response<Vec<u8>> {
    // runtimes serve custom protocols on different URLs (`{scheme}://localhost/...` on wry,
    // `http://{scheme}.localhost/...` on CEF), so the asset is resolved from the URI path only
    let path = request.uri().path().trim_start_matches('/');
    let path = if path.is_empty() { "index.html" } else { path };

    match AUTH_DIST.get_file(path).map(include_dir::File::contents) {
        Some(asset) => tauri::http::Response::builder()
            .header(
                "Content-Type",
                tauri::utils::mime_type::MimeType::parse(asset, path),
            )
            .body(asset.to_vec())
            .unwrap(),
        None => tauri::http::Response::builder()
            .status(200)
            .body(Vec::new())
            .unwrap(),
    }
}

fn context_menu_target_webview<R: Runtime>(window: &Window<R>) -> Option<Webview<R>> {
    let stored = {
        let ctx = window.state::<DevtoolsContextMenu<R>>();
        let guard = ctx.source_webview.lock().unwrap();
        (*guard).clone()
    };
    stored.or_else(|| window.webviews().first().cloned())
}

fn on_menu_event<R: Runtime>(window: &Window<R>, event: &tauri::menu::MenuEvent) {
    match event.id().as_ref() {
        RELOAD_MENU_ID => {
            if let Some(webview) = context_menu_target_webview(window) {
                let _ = webview.reload();
            }
        }
        #[cfg(any(debug_assertions, feature = "context-menu-inspector"))]
        INSPECT_MENU_ID => {
            if let Some(webview) = context_menu_target_webview(window) {
                webview.open_devtools();
            }
        }
        OPEN_DEVTOOLS_MENU_ID => {
            let window = window.clone();

            let devtools_app = window.state::<DevtoolsApp>();
            let devtools_window = if window
                .label()
                .starts_with(STANDALONE_DEVTOOLS_WINDOW_LABEL_PREFIX)
            {
                let parent_label = devtools_app
                    .standalone_window_parents
                    .lock()
                    .unwrap()
                    .get(window.label())
                    .unwrap()
                    .clone();
                if let Some(w) = window.get_window(&parent_label) {
                    w
                } else {
                    return;
                }
            } else {
                window
            };

            let is_devtools_open = devtools_window
                .state::<DevtoolsApp>()
                .webviews
                .lock()
                .unwrap()
                .get(devtools_window.label())
                .is_some_and(|w| w.opened.load(Ordering::Relaxed));

            if !is_devtools_open {
                tauri::async_runtime::spawn(async move {
                    toggle(devtools_window.clone(), devtools_window.state()).await
                });
            }
        }
        _ => (),
    }
}

// kill all children of a process recursively
// based on https://github.com/tauri-apps/tauri/blob/4973d73a237dc5c60618c1011e202278e7a29b5c/tooling/cli/src/dev.rs#L453
fn kill_child_recursively(process_id: u32) {
    #[cfg(windows)]
    {
        let powershell_path = std::env::var("SYSTEMROOT").map_or_else(
            |_| "powershell.exe".to_string(),
            |p| format!("{p}\\System32\\WindowsPowerShell\\v1.0\\powershell.exe"),
        );
        let _ = std::process::Command::new(powershell_path)
      .arg("-NoProfile")
      .arg("-Command")
      .arg(format!("function Kill-Tree {{ Param([int]$ppid); Get-CimInstance Win32_Process | Where-Object {{ $_.ParentProcessId -eq $ppid }} | ForEach-Object {{ Kill-Tree $_.ProcessId }}; Stop-Process -Id $ppid -ErrorAction SilentlyContinue }}; Kill-Tree {}", process_id))
      .status();
    }
    #[cfg(unix)]
    {
        const KILL_CHILDREN_SCRIPT: &[u8] = include_bytes!("../../scripts/kill-children.sh");

        let mut kill_children_script_path = std::env::temp_dir();
        kill_children_script_path.push("kill-children.sh");

        if !kill_children_script_path.exists() {
            if let Ok(mut file) = std::fs::File::create(&kill_children_script_path) {
                use std::{io::Write, os::unix::fs::PermissionsExt};
                let _ = file.write_all(KILL_CHILDREN_SCRIPT);
                let mut permissions = file.metadata().unwrap().permissions();
                permissions.set_mode(0o770);
                let _ = file.set_permissions(permissions);
            }
        }
        let _ = std::process::Command::new(&kill_children_script_path)
            .arg(process_id.to_string())
            .output();
    }
}

fn print_link(connection: &ConnectionInfo) {
    let url = format!(
        "crabnebula-devtools://dash/{}/{}",
        connection.host, connection.port
    );
    let help_text = format!(
        "Alternatively, press {} or right click to open the embedded devtools",
        if cfg!(target_os = "macos") {
            "Cmd + Shift + M"
        } else {
            "Ctrl + Shift + M"
        }
    );

    println!(
        r"
   {} {}{}
   {}   Desktop: {}
       {help_text}
",
        "Tauri Devtools App".bright_purple(),
        "v".purple(),
        env!("CARGO_PKG_VERSION").purple(),
        "→".bright_purple(),
        url.underline().blue()
    );
}

#[cfg(test)]
mod tests {
    use super::{auth_protocol_handler, DevtoolsApp, SPLASHSCREEN_ASSETS_URI_SCHEME};

    fn content_type(uri: &str) -> String {
        let request = tauri::http::Request::builder()
            .uri(uri)
            .body(Vec::new())
            .unwrap();
        let response = auth_protocol_handler(&request);
        response.headers()["Content-Type"]
            .to_str()
            .unwrap()
            .to_string()
    }

    // `Builder::build` is not exercised here: with `__DEVTOOLS_LOCAL_DEVELOPMENT` set (this repository's
    // `.cargo/config.toml`) it builds and spawns the desktop app, so the state is constructed directly
    #[test]
    fn custom_scheme_urls_default_to_the_runtime_format() {
        let app = tauri::test::mock_app();

        // the mock runtime serves custom protocols from `{scheme}://localhost`
        let devtools_app = DevtoolsApp {
            auth_protocol: "isolation-test".into(),
            ..Default::default()
        };
        assert_eq!(
            devtools_app.scheme_url(app.handle(), SPLASHSCREEN_ASSETS_URI_SCHEME),
            format!("{SPLASHSCREEN_ASSETS_URI_SCHEME}://localhost")
        );
        assert_eq!(
            devtools_app.auth_login_url(app.handle()),
            "isolation-test://localhost"
        );

        let devtools_app = DevtoolsApp {
            custom_scheme_url: Some(Box::new(|scheme| format!("http://{scheme}.localhost"))),
            ..Default::default()
        };
        assert_eq!(
            devtools_app.scheme_url(app.handle(), SPLASHSCREEN_ASSETS_URI_SCHEME),
            format!("http://{SPLASHSCREEN_ASSETS_URI_SCHEME}.localhost")
        );
    }

    #[test]
    fn auth_assets_are_resolved_from_the_uri_path() {
        // wry (`{scheme}://localhost`) and CEF / Windows (`http://{scheme}.localhost`) request URIs
        for uri in [
            "isolation-x://localhost/assets/index.css",
            "http://isolation-x.localhost/assets/index.css",
        ] {
            assert_eq!(content_type(uri), "text/css", "{uri}");
        }
        for uri in [
            "isolation-x://localhost",
            "isolation-x://localhost/",
            "http://isolation-x.localhost/?code=1",
        ] {
            assert!(content_type(uri).starts_with("text/html"), "{uri}");
        }
    }
}