microsoft-webui-cli 0.0.23

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.

mod metafile;
mod streaming_api;

use actix_web::{web, App, HttpRequest, HttpResponse, HttpServer};
use anyhow::{Context, Result};
use clap::Args;
use expand_tilde::expand_tilde;
use mime_guess::from_path;
use serde_json::Value;
use std::collections::{HashMap, HashSet};
use std::fs;
use std::io::ErrorKind;
use std::net::{Ipv4Addr, SocketAddrV4, TcpListener};
use std::path::PathBuf;
use std::sync::{Arc, Mutex};
use std::time::Duration;
use tokio_stream::StreamExt;
use webui::streaming::StreamingWriter;
use webui::{Diagnostic, Protocol, WebUIHandler};
use webui_dev_server::{spawn_watcher, sse_handler, LiveReload, WatchConfig};
use webui_handler::plugin::fast_v2::FastV2HydrationPlugin;
use webui_handler::plugin::fast_v3::FastV3HydrationPlugin;
use webui_handler::plugin::webui::WebUIHydrationPlugin;
use webui_handler::{encode_safe, RenderOptions, ResponseWriter};
#[cfg(test)]
use webui_protocol::WebUIProtocol;

use super::common::*;
use crate::utils::error::CliError;
use crate::utils::output;
#[cfg(test)]
use metafile::temp_directory as metafile_temp_directory;
use metafile::write_atomic;

#[derive(Args)]
pub struct ServeArgs {
    #[command(flatten)]
    pub app_args: AppArgs,

    /// Port to bind the development server to
    #[arg(long, default_value_t = 3000)]
    pub port: u16,

    /// Path to the JSON state file used for rendering
    #[arg(long)]
    pub state: Option<PathBuf>,

    /// Optional directory to serve static assets from at /*
    #[arg(long)]
    pub servedir: Option<PathBuf>,

    /// Enable file watching + HMR (disabled by default)
    #[arg(long)]
    pub watch: bool,

    /// Port of the user's API server to proxy route requests to. Encoded path
    /// and query bytes are forwarded unchanged, except the entry route: `/` and
    /// `/index.html` both resolve backend state at `/` (query preserved).
    #[arg(long)]
    pub api_port: Option<u16>,

    /// Design token theme: a path to a JSON file or an npm package name
    /// (e.g., `@microsoft/webui-examples-theme`). Resolved from node_modules
    /// when the value doesn't point to a file on disk. Missing unresolved CSS
    /// tokens fail the build.
    #[arg(long)]
    pub theme: Option<String>,

    /// Comma-separated root component tags to emit as static CDN-loadable
    /// assets, matching `webui build --emit-component-assets`. Their templates
    /// and CSS are parsed and validated (theme tokens, HTML) on every build —
    /// even though they are not part of the initial SSR tree — so authoring
    /// errors in lazily loaded components surface in the dev server. The
    /// compiled `<tag>.webui.js` modules are served from memory.
    #[arg(long, value_delimiter = ',', value_name = "TAGS")]
    pub emit_component_assets: Vec<String>,

    /// Write an esbuild-compatible component asset metafile after each successful build
    #[arg(long, value_name = "PATH", requires = "emit_component_assets")]
    pub metafile: Option<PathBuf>,

    /// Base path for sub-path deployment (e.g., `/commerce/`).
    /// Emits a `<base href>` tag and makes asset paths relative so the
    /// app can be served behind a reverse proxy under a sub-path.
    #[arg(long)]
    pub base_path: Option<String>,
}

/// Resolved paths for `webui serve`.
#[derive(Clone)]
struct ServePaths {
    app_dir: PathBuf,
    state_file: Option<PathBuf>,
    serve_dir: Option<PathBuf>,
    metafile: Option<PathBuf>,
}

impl ServePaths {
    fn from_args(args: &ServeArgs) -> Result<Self> {
        let app_input = expand_tilde(&args.app_args.app)
            .with_context(|| format!("Failed to expand app path: {}", args.app_args.app.display()))?
            .into_owned();

        let app_dir = app_input
            .canonicalize()
            .map_err(|_| CliError::AppFolderNotFound {
                path: args.app_args.app.display().to_string(),
            })?;

        let state_file = match &args.state {
            Some(state_path) => {
                let state_input = expand_tilde(state_path)
                    .with_context(|| {
                        format!("Failed to expand state path: {}", state_path.display())
                    })?
                    .into_owned();

                let canonical =
                    state_input
                        .canonicalize()
                        .map_err(|_| CliError::StateFileNotFound {
                            path: state_path.display().to_string(),
                        })?;

                if !canonical.is_file() {
                    return Err(anyhow::anyhow!(
                        "State path must be a file: {}",
                        canonical.display()
                    ));
                }
                Some(canonical)
            }
            None => None,
        };

        let serve_dir = match &args.servedir {
            Some(serve_arg) => {
                let serve_input = expand_tilde(serve_arg)
                    .with_context(|| {
                        format!(
                            "Failed to expand serve directory path: {}",
                            serve_arg.display()
                        )
                    })?
                    .into_owned();

                let canonical =
                    serve_input
                        .canonicalize()
                        .map_err(|_| CliError::ServeDirNotFound {
                            path: serve_arg.display().to_string(),
                        })?;

                if !canonical.is_dir() {
                    return Err(anyhow::anyhow!(
                        "Serve directory path must be a directory: {}",
                        canonical.display()
                    ));
                }

                Some(canonical)
            }
            None => None,
        };

        if !app_dir.is_dir() {
            return Err(anyhow::anyhow!(
                "App path must be a directory: {}",
                app_dir.display()
            ));
        }

        let metafile = args
            .metafile
            .as_deref()
            .map(expand_tilde)
            .transpose()
            .with_context(|| "Failed to expand metafile path")?
            .map(std::borrow::Cow::into_owned)
            .map(|path| {
                if path.is_absolute() {
                    Ok(path)
                } else {
                    std::env::current_dir().map(|current| current.join(path))
                }
            })
            .transpose()?;

        Ok(Self {
            app_dir,
            state_file,
            serve_dir,
            metafile,
        })
    }

    fn watch_paths(&self) -> Vec<PathBuf> {
        let mut paths = vec![self.app_dir.clone()];

        if let Some(state_file) = &self.state_file {
            paths.push(state_file.clone());
        }

        // Note: `serve_dir` (e.g. `./dist`) is intentionally NOT watched.
        // It is the destination for client bundles that other tools
        // (esbuild, pnpm, E2E harness) write to, and re-reading those
        // writes back through HMR causes spurious page reloads while
        // tests are running. The dev server only needs to react to
        // source changes under `app_dir` and to `state_file`.

        paths
    }
}

/// Thread-safe shared state: the rendered HTML for serving.
struct SharedState {
    rendered_html: String,
    css_files: HashMap<String, String>,
    /// In-memory static component assets (`<tag>.webui.js`) emitted by
    /// `--emit-component-assets`, served from memory like generated CSS.
    component_assets: HashMap<String, String>,
    protocol: Option<Arc<Protocol>>,
    state_data: Option<Value>,
    token_css: Option<HashMap<String, String>>,
    rebuild_error: Option<String>,
    /// Entry fragment ID used for rendering (e.g., "index.html").
    entry: String,
}

/// In-memory writer implementing `ResponseWriter` for the handler.
struct MemoryWriter {
    buf: String,
}

impl MemoryWriter {
    fn with_capacity(cap: usize) -> Self {
        Self {
            buf: String::with_capacity(cap),
        }
    }
}

impl ResponseWriter for MemoryWriter {
    fn write(&mut self, content: &str) -> webui_handler::Result<()> {
        self.buf.push_str(content);
        Ok(())
    }

    fn end(&mut self) -> webui_handler::Result<()> {
        Ok(())
    }
}

/// SSE endpoint path. Root-relative so the script works under any
/// `<base href>` and across sub-path deployments.
const HMR_ENDPOINT: &str = "/__webui/livereload";

/// Environment variable that, when set to a non-empty / non-"0" value,
/// suppresses `--watch` mode at runtime. Used by `xtask e2e` so that
/// shared `start:server` package.json scripts (which include `--watch`
/// for dev) don't enable filesystem watching during E2E test runs,
/// where spurious rebuilds reload the page mid-test.
const WATCH_DISABLE_ENV: &str = "WEBUI_NO_WATCH";

fn watch_disabled_by_env() -> bool {
    match std::env::var(WATCH_DISABLE_ENV) {
        Ok(v) => !v.is_empty() && v != "0",
        Err(_) => false,
    }
}

pub fn execute(args: &ServeArgs) -> Result<()> {
    run(args).inspect_err(|err| {
        output::error(err);
        if let Some(cli_err) = err.chain().find_map(|c| c.downcast_ref::<CliError>()) {
            output::hint(cli_err.hint());
        }
        eprintln!();
    })
}

fn run(args: &ServeArgs) -> Result<()> {
    let paths = ServePaths::from_args(args)?;
    // Allow E2E / CI runs to suppress watch mode without editing the
    // package.json `start:server` script that devs share.
    let watch_enabled = args.watch && !watch_disabled_by_env();
    let livereload: Option<LiveReload> = if watch_enabled {
        Some(LiveReload::new(HMR_ENDPOINT))
    } else {
        None
    };

    let token_file = args
        .theme
        .as_deref()
        .map(|theme| load_theme(theme, &paths.app_dir))
        .transpose()?;

    let render_config = RenderConfig {
        app_args: args.app_args.clone(),
        app_dir: paths.app_dir.clone(),
        state_file: paths.state_file.clone(),
        token_file,
        component_asset_roots: args.emit_component_assets.clone(),
        metafile: paths.metafile.clone(),
        base_path: args.base_path.clone(),
    };

    output::header("WebUI Dev Server");
    output::field("App", &paths.app_dir.display());
    match &paths.state_file {
        Some(f) => output::field("State", &f.display()),
        None => output::field("State", &"(none)"),
    }
    match &paths.serve_dir {
        Some(serve_dir) => output::field("ServeDir", &serve_dir.display()),
        None => output::field("ServeDir", &"(disabled)"),
    }
    if let Some(ref theme) = args.theme {
        output::field("Theme", theme);
    } else {
        output::field("Theme", &"(none)");
    }
    output::field("Entry", &args.app_args.entry);
    output::field("Port", &args.port);
    output::field("CSS", &args.app_args.css);
    if !args.emit_component_assets.is_empty() {
        output::field("Component assets", &args.emit_component_assets.join(", "));
    }
    if let Some(ref metafile) = paths.metafile {
        output::field("Metafile", &metafile.display());
    }
    if let Some(api_port) = args.api_port {
        output::field("API Port", &api_port);
    }
    if watch_enabled {
        output::field("HMR", &format!("enabled (SSE {HMR_ENDPOINT})"));
    } else if args.watch {
        output::field("HMR", &"disabled (WEBUI_NO_WATCH)");
    } else {
        output::field("HMR", &"disabled (pass --watch to enable)");
    }
    eprintln!();

    ensure_local_port_available(args.port)?;

    // Initial build + render
    let initial_result = build_and_render(&render_config, livereload.as_ref())?;
    output::success("Initial build and render complete");
    for advisory in &initial_result.warnings {
        output::warning_diagnostic(advisory);
    }

    let state = Arc::new(Mutex::new(SharedState {
        rendered_html: initial_result.html,
        css_files: initial_result.css_files,
        component_assets: initial_result.component_assets,
        protocol: Some(initial_result.protocol),
        state_data: Some(initial_result.state_data),
        token_css: initial_result.token_css,
        rebuild_error: None,
        entry: args.app_args.entry.clone(),
    }));

    // The watcher handle must outlive the server; dropping it stops the
    // background watcher thread. We store it in an `Option` so that the
    // `--watch=false` branch is a no-op.
    let _watcher_handle = if let Some(active_lr) = &livereload {
        let mut watch_paths_list = paths.watch_paths();

        // Also watch local path component sources
        for extra_dir in
            webui_discovery::collect_watch_paths(&args.app_args.components, &paths.app_dir)
        {
            watch_paths_list.push(extra_dir);
        }

        let handle = start_file_watcher(WatcherConfig {
            watch_paths: watch_paths_list,
            projection_manifests: args.app_args.projection_manifests.clone(),
            state: Arc::clone(&state),
            render_config,
            livereload: active_lr.clone(),
            // Seed dedup with warnings already shown above (keyed by the plain
            // diagnostic body), so the first rebuild does not re-print them.
            initial_warnings: initial_result.warnings.iter().map(|d| d.body()).collect(),
        })?;
        output::success("File watcher started");
        Some(handle)
    } else {
        None
    };

    let addr = format!("127.0.0.1:{}", args.port);
    let bind_addr = addr.clone();
    let server_port = args.port;

    output::field("URL", &format!("http://{addr}/"));
    output::finish("Server is running \u{2014} press Ctrl+C to stop");

    let server_context = web::Data::new(ServerContext {
        state,
        livereload: livereload.clone(),
        assets_dir: paths.serve_dir,
        api_port: args.api_port,
        plugin: args.app_args.plugin,
        base_path: args.base_path.clone(),
        // Pool sized for typical concurrent renders × channel capacity.
        // 256 buffers × 5 KiB ≈ 1.25 MiB peak pool memory — bounded.
        chunk_pool: Arc::new(webui::streaming::ChunkPool::new(
            256,
            StreamingWriter::CHUNK_TARGET + 1024,
        )),
    });
    let lr_data = livereload.map(web::Data::new);

    let has_api_proxy = server_context.api_port.is_some();

    actix_web::rt::System::new()
        .block_on(async move {
            HttpServer::new(move || {
                let mut app = App::new()
                    .app_data(server_context.clone())
                    .route("/", web::get().to(handle_index))
                    .route("/index.html", web::get().to(handle_index));

                if let Some(lr) = &lr_data {
                    app = app
                        .app_data(lr.clone())
                        .route(HMR_ENDPOINT, web::get().to(sse_handler));
                }

                if has_api_proxy {
                    app = app.route("/api/{tail:.*}", web::route().to(handle_api_proxy));
                }

                app = app
                    .route(
                        "/_webui/templates",
                        web::get().to(handle_component_templates),
                    )
                    .route("/{tail:.*}", web::get().to(handle_asset))
                    .default_service(web::route().to(handle_not_found));

                app
            })
            .bind(&bind_addr)
            .map_err(|error| map_bind_error(server_port, &bind_addr, error))?
            .run()
            .await
            .map_err(|e| anyhow::anyhow!("{e}"))
        })
        .with_context(|| format!("Failed to start actix-web server on {addr}"))?;

    Ok(())
}

fn ensure_local_port_available(port: u16) -> Result<()> {
    let bind_addr = SocketAddrV4::new(Ipv4Addr::LOCALHOST, port);
    let listener = TcpListener::bind(bind_addr)
        .map_err(|error| map_bind_error(port, &bind_addr.to_string(), error))?;
    drop(listener);
    Ok(())
}

fn map_bind_error(port: u16, bind_addr: &str, error: std::io::Error) -> anyhow::Error {
    if error.kind() == ErrorKind::AddrInUse {
        return CliError::PortInUse { port }.into();
    }

    anyhow::anyhow!("Failed to bind to {bind_addr}: {error}")
}

#[derive(Clone)]
struct RenderConfig {
    app_args: AppArgs,
    app_dir: PathBuf,
    state_file: Option<PathBuf>,
    /// Loaded theme file used to validate and resolve tokens on each build.
    token_file: Option<webui::TokenFile>,
    /// Root component tags emitted as static assets (`--emit-component-assets`).
    /// Parsed and validated on every build so their authoring errors surface in
    /// the dev server, even though they are not part of the initial SSR tree.
    component_asset_roots: Vec<String>,
    /// Atomic metafile destination updated only after a successful build and render.
    metafile: Option<PathBuf>,
    /// Base path for sub-path deployment (e.g., `/commerce/`).
    base_path: Option<String>,
}

/// Result of a build-and-render cycle.
struct BuildRenderResult {
    html: String,
    css_files: HashMap<String, String>,
    /// Static component assets (`<tag>.webui.js`) keyed by filename.
    component_assets: HashMap<String, String>,
    protocol: Arc<Protocol>,
    state_data: Value,
    token_css: Option<HashMap<String, String>>,
    /// Non-fatal build advisories (warning-severity diagnostics) to frame under
    /// the rebuild line.
    warnings: Vec<Diagnostic>,
}

/// Build the protocol from app templates and render with explicit state data.
fn build_and_render(
    config: &RenderConfig,
    livereload: Option<&LiveReload>,
) -> Result<BuildRenderResult> {
    let mut build_options = config.app_args.to_build_options(&config.app_dir);
    build_options.theme = config.token_file.clone();
    // Parse and validate the static-asset roots too, so theme-token / HTML
    // errors in lazily loaded components (which are not in the SSR tree) fail
    // the dev build instead of being silently skipped.
    build_options.component_asset_roots = config.component_asset_roots.clone();
    build_options.metafile = config.metafile.is_some();
    let build_result = webui::build(build_options).with_context(|| "Build failed")?;
    let token_css = match config.token_file.as_ref() {
        Some(token_file) => Some(
            webui_tokens::resolve_tokens(&build_result.protocol.tokens, token_file)
                .with_context(|| "Token resolution failed")?
                .css,
        ),
        None => None,
    };

    let mut state: Value = match &config.state_file {
        Some(path) => {
            let json = fs::read_to_string(path)
                .with_context(|| format!("Failed to read {}", path.display()))?;
            serde_json::from_str(&json)
                .with_context(|| format!("Failed to parse state JSON from {}", path.display()))?
        }
        None => Value::Object(serde_json::Map::new()),
    };

    // Inject resolved token CSS into state
    if let Some(ref token_css) = token_css {
        webui_tokens::inject_token_css(&mut state, token_css);
    }

    // Inject basePath into state so templates can use {{basePath}}.
    // Default to "/" when no --base-path is set — relative CSS paths
    // like "foo.css" need <base href="/"> to resolve correctly on
    // nested routes (e.g., /contacts/123 → /foo.css, not /contacts/foo.css).
    if let Value::Object(ref mut map) = state {
        let bp = config.base_path.as_deref().unwrap_or("/").to_string();
        map.insert("basePath".into(), Value::String(bp));
    }

    let protocol = Arc::new(Protocol::new(build_result.protocol));

    // Render to memory
    let mut writer = MemoryWriter::with_capacity(4096);
    let handler = create_handler(config.app_args.plugin);
    handler.render(
        &protocol,
        &state,
        &RenderOptions::new(&config.app_args.entry, "/"),
        &mut writer,
    )?;

    let html = match livereload {
        Some(lr) => lr.inject(&writer.buf),
        None => writer.buf,
    };

    if let Some(path) = &config.metafile {
        let metafile = build_result.metafile.as_deref().ok_or_else(|| {
            anyhow::anyhow!("component asset metafile was requested but not generated")
        })?;
        write_atomic(path, metafile)?;
    }

    let css_map: HashMap<String, String> = build_result.css_files.into_iter().collect();
    let component_assets: HashMap<String, String> = build_result
        .component_asset_files
        .into_iter()
        .map(|file| (file.name, file.content))
        .collect();

    Ok(BuildRenderResult {
        html,
        css_files: css_map,
        component_assets,
        protocol,
        state_data: state,
        token_css,
        warnings: build_result.warnings,
    })
}

fn watcher_ignore_paths(metafile: Option<&std::path::Path>) -> Vec<PathBuf> {
    let mut ignore = webui_dev_server::default_ignore_paths();
    if let Ok(out_dir) = std::env::current_dir() {
        ignore.push(out_dir.join("dist"));
    }
    if let Some(metafile) = metafile {
        ignore.extend(metafile::watch_ignore_paths(metafile));
    }
    ignore
}

fn create_handler(plugin: Option<Plugin>) -> WebUIHandler {
    match plugin {
        Some(Plugin::Fast | Plugin::FastV2) => {
            WebUIHandler::with_plugin(|| Box::new(FastV2HydrationPlugin::new()))
        }
        Some(Plugin::FastV3) => {
            WebUIHandler::with_plugin(|| Box::new(FastV3HydrationPlugin::new()))
        }
        Some(Plugin::WebUI) => WebUIHandler::with_plugin(|| Box::new(WebUIHydrationPlugin::new())),
        None => WebUIHandler::new(),
    }
}

fn rebuild_error_response(message: &str, livereload: Option<&LiveReload>) -> HttpResponse {
    if let Some(livereload) = livereload {
        let escaped = encode_safe(message);
        let script = livereload.client_script();
        let mut body = String::with_capacity(message.len() + script.len() + 160);
        body.push_str("<!doctype html><html><head><meta charset=\"utf-8\"><title>");
        body.push_str(
            "WebUI rebuild failed</title></head><body><h1>WebUI rebuild failed</h1><pre>",
        );
        body.push_str(&escaped);
        body.push_str("</pre>");
        body.push_str(script);
        body.push_str("</body></html>");
        return HttpResponse::InternalServerError()
            .content_type("text/html; charset=utf-8")
            .body(body);
    }

    let mut body = String::with_capacity(message.len() + 22);
    body.push_str("WebUI rebuild failed\n\n");
    body.push_str(message);
    HttpResponse::InternalServerError()
        .content_type("text/plain; charset=utf-8")
        .body(body)
}

fn rebuild_error_json_response(message: &str) -> HttpResponse {
    let escaped = match serde_json::to_string(message) {
        Ok(value) => value,
        Err(_) => "\"WebUI rebuild failed\"".to_string(),
    };
    let mut body = String::with_capacity(escaped.len() + 11);
    body.push_str("{\"error\":");
    body.push_str(&escaped);
    body.push('}');
    HttpResponse::InternalServerError()
        .content_type("application/json")
        .body(body)
}

// ── Route handlers ──────────────────────────────────────────────────────

struct ServerContext {
    state: Arc<Mutex<SharedState>>,
    livereload: Option<LiveReload>,
    assets_dir: Option<PathBuf>,
    api_port: Option<u16>,
    plugin: Option<Plugin>,
    /// Base path for sub-path deployment.
    base_path: Option<String>,
    /// Shared chunk-buffer pool. One pool per server; recycled across
    /// every streaming render so steady-state RPS does not allocate
    /// fresh chunk buffers per flush.
    chunk_pool: Arc<webui::streaming::ChunkPool>,
}

#[derive(Debug, Clone, PartialEq, Eq)]
struct RequestPaths {
    route_path: String,
    request_path: String,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
enum SpaFallbackKind {
    None,
    Html,
    Json,
}

fn build_request_paths(relative: &str, query: &str) -> RequestPaths {
    let route_path = if relative.is_empty() {
        "/".to_string()
    } else {
        let mut path = String::with_capacity(relative.len() + 1);
        path.push('/');
        path.push_str(relative);
        path
    };

    if query.is_empty() {
        return RequestPaths {
            request_path: route_path.clone(),
            route_path,
        };
    }

    let mut request_path = String::with_capacity(route_path.len() + query.len() + 1);
    request_path.push_str(&route_path);
    request_path.push('?');
    request_path.push_str(query);

    RequestPaths {
        route_path,
        request_path,
    }
}

fn request_paths(req: &HttpRequest) -> RequestPaths {
    let uri = req.uri();
    let route_path = uri.path().to_string();
    let request_path = uri
        .path_and_query()
        .map_or_else(|| route_path.clone(), |value| value.as_str().to_string());
    RequestPaths {
        route_path,
        request_path,
    }
}

/// Fetch state from the user's API server for a given request path, including query parameters.
async fn fetch_api_state(api_port: u16, path: &str) -> Result<Value, String> {
    let client = awc::Client::new();
    let url = format!("http://127.0.0.1:{api_port}{path}");
    let mut resp = client
        .get(&url)
        .insert_header(("Accept", "application/json"))
        .send()
        .await
        .map_err(|e| format!("API proxy error: {e}"))?;
    let body = resp
        .body()
        .await
        .map_err(|e| format!("API body error: {e}"))?;
    let json: Value = serde_json::from_slice(&body).map_err(|e| format!("API JSON error: {e}"))?;
    // Expect { "state": { ... } }, fall back to entire response
    Ok(extract_api_state(json))
}

/// Resolve state for a request: try API proxy first, then fall back to file state.
async fn resolve_state(context: &ServerContext, request_path: &str) -> Value {
    let (mut state, token_css) = if let Some(api_port) = context.api_port {
        match fetch_api_state(api_port, request_path).await {
            Ok(state) => {
                let token_css = context.state.lock().ok().and_then(|s| s.token_css.clone());
                (state, token_css)
            }
            Err(e) => {
                eprintln!("  {} {e}", console::style("\u{26a0}").yellow());
                match context.state.lock() {
                    Ok(s) => (
                        s.state_data
                            .clone()
                            .unwrap_or_else(|| Value::Object(serde_json::Map::new())),
                        s.token_css.clone(),
                    ),
                    Err(_) => (Value::Object(serde_json::Map::new()), None),
                }
            }
        }
    } else {
        match context.state.lock() {
            Ok(s) => (
                s.state_data
                    .clone()
                    .unwrap_or_else(|| Value::Object(serde_json::Map::new())),
                s.token_css.clone(),
            ),
            Err(_) => (Value::Object(serde_json::Map::new()), None),
        }
    };

    // Inject resolved token CSS into state so signals like
    // /*{{{tokens.light}}}*/ resolve at render time, regardless of
    // whether state came from a static file or the API server.
    if let Some(ref token_css) = token_css {
        webui_tokens::inject_token_css(&mut state, token_css);
    }

    // Inject basePath into state — default "/" for correct CSS resolution.
    if let Value::Object(ref mut map) = state {
        let bp = context.base_path.as_deref().unwrap_or("/").to_string();
        map.insert("basePath".into(), Value::String(bp));
    }

    state
}

/// Render a full HTML page using route matching from `route_path` and state lookup from
/// `request_path`, which may include a query string. Streams chunks via
/// [`StreamingWriter`]; when livereload is active, the dev-mode `<script>`
/// is spliced before `</body>` via `RenderOptions::with_body_inject` —
/// the handler emits it at the parser-synthesized `body_end` signal
/// boundary, with zero scan cost and no risk of false-marker mis-fire
/// on `</body>` literals appearing inside HTML comments / `srcdoc`.
async fn render_page_response(
    context: &web::Data<ServerContext>,
    route_path: &str,
    request_path: &str,
) -> HttpResponse {
    // One lock acquisition for a consistent snapshot of the rebuild status and
    // the protocol/entry it produced. Reading these separately could mix a
    // "no error" check with a protocol from a different rebuild generation.
    let (rebuild_error, protocol, entry) = match context.state.lock() {
        Ok(s) => (s.rebuild_error.clone(), s.protocol.clone(), s.entry.clone()),
        Err(_) => return HttpResponse::InternalServerError().body("Internal Server Error"),
    };

    if let Some(error) = rebuild_error.as_deref() {
        return rebuild_error_response(error, context.livereload.as_ref());
    }

    let Some(proto) = protocol else {
        return HttpResponse::InternalServerError().body("Protocol not available");
    };
    let plugin = context.plugin;
    let livereload_script: Option<Arc<str>> =
        context.livereload.as_ref().map(|lr| lr.client_script_arc());
    let route_params =
        webui_handler::route_handler::collect_nested_route_params(&proto, &entry, route_path);

    let mut state = if let Some(api_port) = context.api_port {
        let client = awc::Client::new();
        let url = format!("http://127.0.0.1:{api_port}{request_path}");
        match client
            .get(&url)
            .insert_header(("Accept", streaming_api::ACCEPT))
            .send()
            .await
        {
            Ok(response) if streaming_api::is_stream(response.headers()) => {
                let status = response.status();
                if !status.is_success() {
                    // The upstream refused before writing a single record, so no
                    // boundary has reached the browser and rule 19's "never
                    // degrade a live stream to buffering" does not apply. Treat
                    // it like any other pre-stream acquisition failure and
                    // render the page from fallback state, rather than handing
                    // the browser a raw upstream error body in place of the app.
                    log_api_state_warning(&format!(
                        "API stream unavailable (HTTP {status}); rendering with fallback state"
                    ));
                    fallback_state(context)
                } else {
                    let backend = response.map(|chunk| chunk.map_err(|error| error.to_string()));
                    let defaults = streaming_state_defaults(context, route_params);
                    return streaming_api::render(
                        backend,
                        streaming_api::RenderConfig {
                            protocol: proto,
                            entry,
                            route_path: route_path.to_owned(),
                            plugin,
                            body_inject: livereload_script,
                            chunk_pool: Arc::clone(&context.chunk_pool),
                        },
                        defaults,
                    )
                    .await;
                }
            }
            Ok(mut response) => match response.body().await {
                Ok(body) => match parse_api_state(&body) {
                    Ok(state) => state,
                    Err(error) => {
                        log_api_state_warning(&error);
                        fallback_state(context)
                    }
                },
                Err(error) => {
                    log_api_state_warning(&format!("API body error: {error}"));
                    fallback_state(context)
                }
            },
            Err(error) => {
                log_api_state_warning(&format!("API proxy error: {error}"));
                fallback_state(context)
            }
        }
    } else {
        fallback_state(context)
    };

    let defaults = streaming_state_defaults(context, route_params);
    defaults.apply(&mut state);
    render_buffered_page(
        streaming_api::RenderConfig {
            protocol: proto,
            entry,
            route_path: route_path.to_owned(),
            plugin,
            body_inject: livereload_script,
            chunk_pool: Arc::clone(&context.chunk_pool),
        },
        state,
    )
}

fn parse_api_state(body: &[u8]) -> Result<Value, String> {
    let json: Value =
        serde_json::from_slice(body).map_err(|error| format!("API JSON error: {error}"))?;
    Ok(extract_api_state(json))
}

fn extract_api_state(mut json: Value) -> Value {
    if let Value::Object(object) = &mut json {
        if let Some(state) = object.remove("state") {
            return state;
        }
    }
    json
}

fn fallback_state(context: &ServerContext) -> Value {
    context
        .state
        .lock()
        .ok()
        .and_then(|state| state.state_data.clone())
        .unwrap_or_else(|| Value::Object(serde_json::Map::new()))
}

fn streaming_state_defaults(
    context: &ServerContext,
    route_params: HashMap<String, String>,
) -> streaming_api::StateDefaults {
    let token_css = context
        .state
        .lock()
        .ok()
        .and_then(|state| state.token_css.clone());
    streaming_api::StateDefaults::new(
        token_css,
        context.base_path.as_deref().unwrap_or("/").to_owned(),
        route_params,
    )
}

fn log_api_state_warning(message: &str) {
    eprintln!("  {} {message}", console::style("\u{26a0}").yellow());
}

fn render_buffered_page(config: streaming_api::RenderConfig, state: Value) -> HttpResponse {
    let route_path_for_log = config.route_path.clone();

    // Bounded channel: backpressure when client is slow, no unbounded
    // memory growth. Capacity is in chunks (≈ 4 KB each).
    let (tx, rx) =
        tokio::sync::mpsc::channel::<bytes::Bytes>(StreamingWriter::DEFAULT_CHANNEL_CAPACITY);
    actix_web::rt::task::spawn_blocking(move || {
        // 30 s flush deadline caps slow-loris DoS: an attacker can pin
        // a render thread for at most 30 s per chunk, then we abort
        // and free the thread.
        // Pool-acquired chunk buffers recycle across requests — steady-
        // state RPS does not allocate fresh chunk Vec per flush.
        let mut writer = StreamingWriter::new_pooled(tx, Arc::clone(&config.chunk_pool))
            .with_flush_timeout(std::time::Duration::from_secs(30));
        // Build RenderOptions with optional body_inject for livereload.
        // The handler emits the inject string at the structural
        // body_end boundary identified by the parser — zero scan cost,
        // no risk of false-marker mis-firing on `</body>` literals
        // appearing inside HTML comments / srcdoc / inline scripts.
        let opts_owner = RenderOptions::new(&config.entry, &config.route_path);
        let opts = match config.body_inject.as_deref() {
            Some(script) => opts_owner.with_body_inject(script),
            None => opts_owner,
        };
        let handler = create_handler(config.plugin);
        if let Err(e) = handler.render(&config.protocol, &state, &opts, &mut writer) {
            // Status 200 + headers are already on the wire — we cannot
            // return an HTTP error. Log the detail so ops sees it;
            // emit a fixed HTML comment so an attacker-controlled
            // error message cannot break out of the comment via `-->`.
            log::error!("render failed for {route_path_for_log}: {e}");
            let _ = ResponseWriter::write(&mut writer, "<!-- webui: render error -->");
            if let Err(flush_error) = ResponseWriter::end(&mut writer) {
                log::debug!("render stream truncated for {route_path_for_log}: {flush_error}");
            }
        }
    });

    // Zero-overhead Stream adapter (no async_stream! coroutine).
    let stream =
        tokio_stream::wrappers::ReceiverStream::new(rx).map(Ok::<bytes::Bytes, actix_web::Error>);
    HttpResponse::Ok()
        .content_type("text/html; charset=utf-8")
        // Streaming responses with attacker-influencable timing should
        // not be cached by intermediaries; the body may be partial on
        // error paths.
        .insert_header(("Cache-Control", "no-store"))
        .streaming(stream)
}

async fn handle_index(req: HttpRequest, context: web::Data<ServerContext>) -> HttpResponse {
    // JSON partial render for client-side navigation
    if wants_json(&req) {
        let paths = build_request_paths("", req.query_string());
        return handle_json_partial(&req, &context, paths).await;
    }

    // With API proxy, render on-the-fly with fresh state
    if context.api_port.is_some() {
        let paths = build_request_paths("", req.query_string());
        return render_page_response(&context, &paths.route_path, &paths.request_path).await;
    }

    // Without API proxy, serve pre-rendered HTML
    let html = match context.state.lock() {
        Ok(s) => {
            if let Some(error) = s.rebuild_error.as_deref() {
                return rebuild_error_response(error, context.livereload.as_ref());
            }
            s.rendered_html.clone()
        }
        Err(_) => return HttpResponse::InternalServerError().body("Internal Server Error"),
    };

    HttpResponse::Ok()
        .content_type("text/html; charset=utf-8")
        .body(html)
}

async fn handle_component_templates(
    req: HttpRequest,
    context: web::Data<ServerContext>,
) -> HttpResponse {
    let qs = req.query_string();
    let mut tags: Vec<&str> = Vec::new();
    let mut inv = String::new();
    for pair in qs.split('&') {
        if let Some((k, v)) = pair.split_once('=') {
            match k {
                "t" => tags.extend(v.split(',')),
                "inv" => inv = v.to_string(),
                _ => {}
            }
        }
    }
    if tags.is_empty() {
        return HttpResponse::BadRequest()
            .content_type("application/json")
            .body(r#"{"error":"missing ?t= parameter"}"#);
    }
    let Ok(state) = context.state.lock() else {
        return HttpResponse::InternalServerError()
            .content_type("application/json")
            .body(r#"{"error":"lock poisoned"}"#);
    };
    if let Some(error) = state.rebuild_error.as_deref() {
        return rebuild_error_json_response(error);
    }
    let Some(ref protocol) = state.protocol else {
        return HttpResponse::InternalServerError()
            .content_type("application/json")
            .body(r#"{"error":"no protocol"}"#);
    };
    let result = match protocol.render_component_templates(&tags, &inv) {
        Ok(v) => v,
        Err(e) => {
            return HttpResponse::InternalServerError()
                .content_type("application/json")
                .body(format!(r#"{{"error":"{}"}}"#, e));
        }
    };
    HttpResponse::Ok()
        .content_type("application/json")
        .json(result)
}

async fn handle_asset(
    req: HttpRequest,
    path: web::Path<String>,
    context: web::Data<ServerContext>,
) -> HttpResponse {
    let relative = path.into_inner();

    // Check in-memory generated files first (CSS and static component assets,
    // produced by the build). These take precedence over `--servedir` so the
    // dev server always serves the freshly built output.
    if let Ok(s) = context.state.lock() {
        if let Some(css) = s.css_files.get(&relative) {
            return HttpResponse::Ok()
                .content_type("text/css; charset=utf-8")
                .body(css.clone());
        }
        if let Some(asset) = s.component_assets.get(&relative) {
            // Served as a JS module: the framework loads it via dynamic
            // `import()`, which the browser rejects under a non-JS MIME type.
            return HttpResponse::Ok()
                .content_type("text/javascript; charset=utf-8")
                .body(asset.clone());
        }
    }

    let Some(assets_dir) = &context.assets_dir else {
        // No assets dir: let the Accept header decide whether this was a route
        // navigation/partial request or a missing asset fetch.
        return spa_fallback(&req, &context).await;
    };

    let asset_path = assets_dir.join(&relative);

    let canonical = match asset_path.canonicalize() {
        Ok(p) => p,
        Err(_) => {
            // File not found: let the Accept header decide whether this was a
            // route navigation/partial request or a missing asset fetch.
            return spa_fallback(&req, &context).await;
        }
    };

    if !canonical.starts_with(assets_dir) {
        return HttpResponse::Forbidden().body("Forbidden");
    }

    let body = match fs::read(&canonical) {
        Ok(bytes) => bytes,
        Err(_) => return spa_fallback(&req, &context).await,
    };

    let content_type = from_path(&canonical).first_or_octet_stream();

    HttpResponse::Ok()
        .content_type(content_type.as_ref())
        .body(body)
}

fn accept_media_q(params: &str) -> f32 {
    for raw_param in params.split(';') {
        let Some((key, value)) = raw_param.trim().split_once('=') else {
            continue;
        };
        if key.trim().eq_ignore_ascii_case("q") {
            // HTTP qvalues are finite and within 0..=1. Anything outside that
            // range is malformed and falls back to the default of 1.0 so an
            // invalid header cannot force a 404 or skew tie-breaking.
            return value
                .trim()
                .parse::<f32>()
                .ok()
                .filter(|q| (0.0..=1.0).contains(q))
                .unwrap_or(1.0);
        }
    }
    1.0
}

/// Select the SPA fallback response explicitly accepted by the request.
///
/// `q=0` disables that media type, while malformed or out-of-range q values
/// (outside `0..=1`) are treated as absent with the default q of 1.0. When HTML
/// and JSON have the same highest acceptable q value, JSON wins because it is
/// only sent by clients opting into partial render.
fn spa_fallback_kind(req: &HttpRequest) -> SpaFallbackKind {
    let Some(accept) = req.headers().get("accept").and_then(|v| v.to_str().ok()) else {
        return SpaFallbackKind::None;
    };

    let mut html_q = 0.0;
    let mut json_q = 0.0;
    for raw_media in accept.split(',') {
        let (media, params) = raw_media
            .split_once(';')
            .map_or((raw_media, ""), |(value, params)| (value, params));
        let q = accept_media_q(params);
        if q <= 0.0 {
            continue;
        }

        let media = media.trim();
        if media.eq_ignore_ascii_case("text/html")
            || media.eq_ignore_ascii_case("application/xhtml+xml")
        {
            if q > html_q {
                html_q = q;
            }
        } else if media.eq_ignore_ascii_case("application/json") && q > json_q {
            json_q = q;
        }
    }

    if html_q <= 0.0 && json_q <= 0.0 {
        SpaFallbackKind::None
    } else if json_q >= html_q {
        SpaFallbackKind::Json
    } else {
        SpaFallbackKind::Html
    }
}

/// Check if the request explicitly accepts JSON (for partial render).
fn wants_json(req: &HttpRequest) -> bool {
    spa_fallback_kind(req) == SpaFallbackKind::Json
}

/// SPA fallback: serve HTML or JSON partial depending on Accept header.
/// Activates for explicit document navigation or JSON partial requests.
async fn spa_fallback(req: &HttpRequest, context: &web::Data<ServerContext>) -> HttpResponse {
    let kind = spa_fallback_kind(req);
    if kind == SpaFallbackKind::None {
        return HttpResponse::NotFound().body("Not Found");
    }

    // Actix decodes `web::Path` values. Route matching and backend state
    // requests must instead receive the original encoded request target.
    let paths = request_paths(req);

    // JSON partial render: return { state, templates } for client-side navigation.
    if kind == SpaFallbackKind::Json {
        return handle_json_partial(req, context, paths).await;
    }

    render_page_response(context, &paths.route_path, &paths.request_path).await
}

/// Handle a JSON partial render request for client-side navigation.
///
/// Returns `{ state, templates, inventory, path, chain }` where:
/// - `templates` only includes f-templates the client doesn't already have
/// - `inventory` is the updated hex bitmask including the new templates
async fn handle_json_partial(
    req: &HttpRequest,
    context: &web::Data<ServerContext>,
    paths: RequestPaths,
) -> HttpResponse {
    // Clone protocol from shared state (release lock quickly)
    let (protocol, entry) = match context.state.lock() {
        Ok(s) => {
            if let Some(error) = s.rebuild_error.as_deref() {
                return rebuild_error_json_response(error);
            }
            (s.protocol.clone(), s.entry.clone())
        }
        Err(_) => {
            return HttpResponse::InternalServerError().body(r#"{"error":"Internal server error"}"#)
        }
    };

    let mut state_data = resolve_state(context, &paths.request_path).await;

    // Inject route params into state from walking the fragment graph.
    if let Value::Object(ref mut map) = state_data {
        if let Some(proto) = &protocol {
            let nested_params = webui_handler::route_handler::collect_nested_route_params(
                proto,
                &entry,
                &paths.route_path,
            );
            for (k, v) in &nested_params {
                map.insert(k.clone(), Value::String(v.clone()));
            }
        }
    }

    // Get needed component templates via the handler's graph walk + inventory filter
    let client_inv_hex = req
        .headers()
        .get("x-webui-inventory")
        .and_then(|v| v.to_str().ok())
        .unwrap_or_default()
        .to_string();

    // Build the complete partial response (templateStyles, templates, inventory, path, chain)
    let partial = if let Some(proto) = &protocol {
        let state_json = match serde_json::to_string(&state_data) {
            Ok(value) => value,
            Err(error) => {
                return HttpResponse::InternalServerError()
                    .content_type("application/json")
                    .body(format!(
                        r#"{{"error":"state serialization failed: {error}"}}"#
                    ));
            }
        };
        match proto.render_partial(&state_json, &entry, &paths.route_path, &client_inv_hex) {
            Ok(value) => value,
            Err(e) => {
                return HttpResponse::InternalServerError()
                    .content_type("application/json")
                    .body(format!(r#"{{"error":"{}"}}"#, e));
            }
        }
    } else {
        "{}".to_string()
    };

    HttpResponse::Ok()
        .content_type("application/json")
        .body(partial)
}

#[cfg(test)]
fn collect_needed_template_names(
    protocol: &WebUIProtocol,
    entry_fragment_id: &str,
    request_path: &str,
    inventory_hex: &str,
) -> (Vec<String>, String) {
    let protocol = Protocol::new(protocol.clone());
    let json = protocol
        .render_partial("{}", entry_fragment_id, request_path, inventory_hex)
        .unwrap();
    let response: Value = serde_json::from_str(&json).unwrap();
    let names = response["templates"]
        .as_object()
        .map(|templates| templates.keys().cloned().collect())
        .unwrap_or_default();
    let inventory = response["inventory"]
        .as_str()
        .unwrap_or_default()
        .to_string();
    (names, inventory)
}

/// Forward requests under `/api/*` to the user's API server.
async fn handle_api_proxy(
    req: HttpRequest,
    body: web::Bytes,
    context: web::Data<ServerContext>,
) -> HttpResponse {
    let Some(api_port) = context.api_port else {
        return HttpResponse::NotFound().body("Not Found");
    };

    let uri = req.uri();
    let path_and_query = uri
        .path_and_query()
        .map_or(uri.path(), |value| value.as_str());
    const API_URL_PREFIX: &str = "http://127.0.0.1:";
    const MAX_PORT_DIGITS: usize = 5;
    let mut url =
        String::with_capacity(API_URL_PREFIX.len() + MAX_PORT_DIGITS + path_and_query.len());
    url.push_str(API_URL_PREFIX);
    // Write the port digits straight into the reserved capacity instead of
    // allocating a temporary `String` via `to_string()` on the proxy hot path.
    use std::fmt::Write as _;
    let _ = write!(url, "{api_port}");
    url.push_str(path_and_query);

    let client = awc::Client::new();
    let mut proxy_req = client.request(req.method().clone(), &url);

    // Forward content-type header if present
    if let Some(ct) = req.headers().get("content-type") {
        proxy_req = proxy_req.insert_header(("content-type", ct.clone()));
    }

    let result = if body.is_empty() {
        proxy_req.send().await
    } else {
        proxy_req.send_body(body).await
    };

    match result {
        Ok(mut resp) => {
            let status = resp.status();
            match resp.body().await {
                Ok(response_body) => {
                    let mut builder = HttpResponse::build(status);
                    if let Some(ct) = resp.headers().get("content-type") {
                        builder.insert_header(("content-type", ct.clone()));
                    }
                    builder.body(response_body)
                }
                Err(e) => HttpResponse::BadGateway().body(format!("API proxy body error: {e}")),
            }
        }
        Err(e) => HttpResponse::BadGateway().body(format!("API proxy error: {e}")),
    }
}

async fn handle_not_found() -> HttpResponse {
    HttpResponse::NotFound().body("Not Found")
}

// ── File watcher ────────────────────────────────────────────────────────

/// Filesystem-event debounce window. Editors often save in multiple
/// bursts; coalescing into one rebuild per burst feels right.
const WATCH_DEBOUNCE: Duration = Duration::from_millis(50);

/// Configuration for the file watcher.
struct WatcherConfig {
    watch_paths: Vec<PathBuf>,
    projection_manifests: Vec<PathBuf>,
    state: Arc<Mutex<SharedState>>,
    render_config: RenderConfig,
    livereload: LiveReload,
    /// Warnings already printed by the initial build, used to seed rebuild
    /// dedup so they are not re-printed on the next rebuild.
    initial_warnings: Vec<String>,
}

/// Start a debounced filesystem watcher that rebuilds and re-renders
/// when template, data, or asset files change. The returned handle owns
/// the background watcher thread; it must be kept alive for the lifetime
/// of the server.
fn start_file_watcher(config: WatcherConfig) -> Result<webui_dev_server::WatcherHandle> {
    let WatcherConfig {
        watch_paths,
        projection_manifests,
        state,
        render_config,
        livereload,
        initial_warnings,
    } = config;

    // The shared rebuild worker handles tick coalescing, success/error
    // reporting (rolling line + timestamps), and livereload broadcast.
    // The closure here is just the cli-specific render-and-update step.
    //
    // Rebuild advisories are deduplicated: a full-app rebuild fires on every
    // watched change, but a warning is only worth printing when it first
    // appears. `seen` holds the previous rebuild's warning set (seeded with the
    // initial build's), so editing an unrelated file does not re-spam unchanged
    // warnings. A resolved-then-reintroduced warning prints again. Errors are
    // intentionally not deduplicated — a broken build is surfaced every rebuild.
    let lr_for_inject = livereload.clone();
    let mut seen: HashSet<String> = initial_warnings.into_iter().collect();
    let state_for_rebuild = Arc::clone(&state);
    let retry_state = Arc::clone(&state);
    let metafile_ignore = render_config.metafile.clone();
    let tick_tx = webui_dev_server::spawn_rebuild_worker(livereload, move || {
        let warnings =
            rebuild_and_update_state(&render_config, &lr_for_inject, &state_for_rebuild)?;
        Ok(take_new_warnings(&mut seen, warnings))
    });
    let retry_unchanged_when = Arc::new(move || {
        retry_state
            .lock()
            .is_ok_and(|state| state.rebuild_error.is_some())
    });

    let ignore = watcher_ignore_paths(metafile_ignore.as_deref());

    spawn_watcher(
        WatchConfig {
            paths: watch_paths,
            explicit_files: projection_manifests,
            ignore,
            debounce: WATCH_DEBOUNCE,
            retry_unchanged_when: Some(retry_unchanged_when),
        },
        move |paths: Vec<std::path::PathBuf>| {
            // Forward the changed paths so the rebuild line can name the
            // triggering file. If the worker thread has already terminated,
            // ignore send errors.
            let _ = tick_tx.try_send(paths);
        },
    )
}

/// Return the colorized display bodies for warnings in `current` that were not
/// in `seen`, then replace `seen` with the current warning set (keyed by each
/// diagnostic's plain `body()`).
///
/// Dedupes dev-server rebuild advisories: a warning prints only when it first
/// appears (or reappears after being resolved), so editing an unrelated file —
/// which still triggers a full-app rebuild — does not re-spam unchanged
/// warnings. The returned strings are the per-line-colorized multi-line bodies
/// the reporter prints under a `⚠ build warning:` marker.
fn take_new_warnings(seen: &mut HashSet<String>, current: Vec<Diagnostic>) -> Vec<String> {
    let mut new_displays = Vec::new();
    let mut current_keys = HashSet::with_capacity(current.len());
    for diag in &current {
        let key = diag.body();
        if !seen.contains(&key) {
            new_displays.push(crate::utils::output::styled_diagnostic_body(diag));
        }
        current_keys.insert(key);
    }
    *seen = current_keys;
    new_displays
}

fn rebuild_and_update_state(
    render_config: &RenderConfig,
    livereload: &LiveReload,
    state: &Arc<Mutex<SharedState>>,
) -> Result<Vec<Diagnostic>, webui_dev_server::RebuildError> {
    match build_and_render(render_config, Some(livereload)) {
        Ok(result) => match state.lock() {
            Ok(mut s) => {
                s.rendered_html = result.html;
                s.css_files = result.css_files;
                s.component_assets = result.component_assets;
                s.protocol = Some(result.protocol);
                s.state_data = Some(result.state_data);
                s.token_css = result.token_css;
                s.rebuild_error = None;
                // The rebuild worker prints these under the "rebuilt" line.
                Ok(result.warnings)
            }
            Err(_) => Err(webui_dev_server::RebuildError::plain(
                "shared state mutex poisoned".to_owned(),
            )),
        },
        Err(err) => {
            let (display, message) = crate::utils::output::build_error_renderings(&err);
            if let Ok(mut s) = state.lock() {
                s.rebuild_error = Some(message.clone());
            }
            Err(webui_dev_server::RebuildError::new(display, message))
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use actix_web::body::to_bytes;
    use actix_web::http::StatusCode;
    use actix_web::test as actix_test;
    use std::sync::atomic::{AtomicUsize, Ordering};
    use tempfile::TempDir;
    use webui_protocol::{FragmentList, WebUIFragment, WebUIProtocol, WebUiFragmentRoute};

    fn create_app_dir(files: &[(&str, &str)]) -> TempDir {
        let dir = TempDir::new().unwrap();
        for (name, content) in files {
            let path = dir.path().join(name);
            if let Some(parent) = path.parent() {
                fs::create_dir_all(parent).unwrap();
            }
            fs::write(&path, content).unwrap();
        }
        dir
    }

    fn test_server_context(api_port: u16) -> web::Data<ServerContext> {
        web::Data::new(ServerContext {
            state: Arc::new(Mutex::new(SharedState {
                rendered_html: "<html><body>ok</body></html>".to_string(),
                css_files: HashMap::new(),
                component_assets: HashMap::new(),
                protocol: None,
                state_data: None,
                token_css: None,
                rebuild_error: None,
                entry: "index.html".to_string(),
            })),
            livereload: None,
            assets_dir: None,
            api_port: Some(api_port),
            plugin: None,
            base_path: None,
            chunk_pool: Arc::new(webui::streaming::ChunkPool::new(
                4,
                StreamingWriter::CHUNK_TARGET + 1024,
            )),
        })
    }

    fn test_route_context(protocol: Arc<Protocol>) -> web::Data<ServerContext> {
        web::Data::new(ServerContext {
            state: Arc::new(Mutex::new(SharedState {
                rendered_html: "<html><body>ok</body></html>".to_string(),
                css_files: HashMap::new(),
                component_assets: HashMap::new(),
                protocol: Some(protocol),
                state_data: Some(Value::Object(serde_json::Map::new())),
                token_css: None,
                rebuild_error: None,
                entry: "index.html".to_string(),
            })),
            livereload: None,
            assets_dir: None,
            api_port: None,
            plugin: None,
            base_path: None,
            chunk_pool: Arc::new(webui::streaming::ChunkPool::new(
                4,
                StreamingWriter::CHUNK_TARGET + 1024,
            )),
        })
    }

    fn dotted_route_protocol() -> Arc<Protocol> {
        let mut fragments = HashMap::new();
        fragments.insert(
            "index.html".to_string(),
            FragmentList {
                fragments: vec![WebUIFragment::route_from(WebUiFragmentRoute {
                    path: "/docs/:version".to_string(),
                    fragment_id: "docs-page".to_string(),
                    exact: true,
                    keep_alive: false,
                    ..Default::default()
                })],
            },
        );
        fragments.insert(
            "docs-page".to_string(),
            FragmentList {
                fragments: vec![WebUIFragment::raw("<main>docs</main>")],
            },
        );
        Arc::new(Protocol::new(WebUIProtocol::with_tokens(
            fragments,
            Vec::new(),
        )))
    }

    fn start_request_target_server() -> (u16, actix_web::dev::ServerHandle, Arc<Mutex<Vec<String>>>)
    {
        let request_targets = Arc::new(Mutex::new(Vec::new()));
        let server_targets = Arc::clone(&request_targets);
        let listener = TcpListener::bind((Ipv4Addr::LOCALHOST, 0)).unwrap();
        let port = listener.local_addr().unwrap().port();
        let server = HttpServer::new(move || {
            let request_targets = Arc::clone(&server_targets);
            App::new().default_service(web::to(move |req: HttpRequest| {
                let request_targets = Arc::clone(&request_targets);
                async move {
                    let request_target = req.uri().path_and_query().map_or_else(
                        || req.path().to_string(),
                        |value| value.as_str().to_string(),
                    );
                    request_targets.lock().unwrap().push(request_target.clone());
                    HttpResponse::Ok().json(serde_json::json!({
                        "state": { "requestTarget": request_target }
                    }))
                }
            }))
        })
        .listen(listener)
        .unwrap()
        .run();
        let handle = server.handle();
        actix_web::rt::spawn(server);
        (port, handle, request_targets)
    }

    #[test]
    fn test_take_new_warnings_suppresses_repeats_and_surfaces_changes() {
        // `take_new_warnings` dedupes on each diagnostic's plain `body()` and
        // returns the styled display bodies for the newly-appeared warnings.
        fn warn(token: &str) -> Diagnostic {
            Diagnostic::warning(format!("unthemed CSS token --{token}"))
        }
        let key = |token: &str| warn(token).body();

        // Seed with the initial build's warning (mirrors run(), keyed by body()).
        let mut seen: HashSet<String> = [key("colr-brand")].into_iter().collect();

        // Unrelated rebuild: same warning set → nothing new to print.
        assert!(take_new_warnings(&mut seen, vec![warn("colr-brand")]).is_empty());

        // A new warning appears → only the new one is surfaced.
        let new = take_new_warnings(&mut seen, vec![warn("colr-brand"), warn("colr-accent")]);
        assert_eq!(new.len(), 1);
        assert!(new[0].contains("--colr-accent"), "display: {}", new[0]);

        // Both persist → silent.
        assert!(
            take_new_warnings(&mut seen, vec![warn("colr-brand"), warn("colr-accent")]).is_empty()
        );

        // `colr-brand` resolved (only accent remains) → still silent (resolutions
        // aren't re-announced), but `seen` now drops it.
        assert!(take_new_warnings(&mut seen, vec![warn("colr-accent")]).is_empty());

        // `colr-brand` reintroduced → surfaced again because it left the set.
        let reintroduced =
            take_new_warnings(&mut seen, vec![warn("colr-brand"), warn("colr-accent")]);
        assert_eq!(reintroduced.len(), 1);
        assert!(
            reintroduced[0].contains("--colr-brand"),
            "display: {}",
            reintroduced[0]
        );
    }

    #[test]
    fn test_build_and_render_simple() {
        let app = create_app_dir(&[("index.html", "<h1>Hello</h1>"), ("state.json", "{}")]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: Some(app.path().join("state.json")),
            token_file: None,
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };
        let hmr = LiveReload::new(HMR_ENDPOINT);
        let BuildRenderResult { html, .. } = build_and_render(&config, Some(&hmr)).unwrap();
        assert!(html.contains("<h1>Hello</h1>"));
    }

    #[test]
    fn test_build_and_render_with_state() {
        let app = create_app_dir(&[
            ("index.html", "<p>{{name}}</p>"),
            ("state.json", r#"{"name":"WebUI"}"#),
        ]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: Some(app.path().join("state.json")),
            token_file: None,
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };
        let hmr = LiveReload::new(HMR_ENDPOINT);
        let BuildRenderResult { html, .. } = build_and_render(&config, Some(&hmr)).unwrap();
        assert!(html.contains("<p>WebUI</p>"));
    }

    #[test]
    fn test_build_and_render_selects_fast_plugin_versions() {
        let app = create_app_dir(&[
            (
                "index.html",
                "<html><head></head><body><my-card></my-card></body></html>",
            ),
            ("my-card.html", "<span>{{name}}</span>"),
            ("state.json", r#"{"name":"Alice"}"#),
        ]);

        let render = |plugin| {
            let config = RenderConfig {
                app_args: AppArgs {
                    app: app.path().to_path_buf(),
                    entry: "index.html".to_string(),
                    css: CssStrategy::Link,
                    dom: DomStrategy::Shadow,
                    plugin,
                    components: Vec::new(),
                    projection_manifests: Vec::new(),
                    asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                    css_public_base: None,
                    legal_comments: LegalComments::Inline,
                },
                app_dir: app.path().to_path_buf(),
                state_file: Some(app.path().join("state.json")),
                token_file: None,
                component_asset_roots: Vec::new(),
                metafile: None,
                base_path: None,
            };
            build_and_render(&config, None).unwrap().html
        };

        let fast = render(Some(Plugin::Fast));
        assert!(fast.contains("<!--fe-b$$start$$0$$name$$fe-b-->"));
        assert!(!fast.contains("<!--fe:b-->"));
        assert!(fast.contains("id=\"webui-data\""));
        assert!(!fast.contains("window.__webui"));
        assert!(!fast.contains(r#""templates""#));
        assert!(!fast.contains("templateFns"));

        let fast_v2 = render(Some(Plugin::FastV2));
        assert!(fast_v2.contains("<!--fe-b$$start$$0$$name$$fe-b-->"));
        assert!(!fast_v2.contains("<!--fe:b-->"));
        assert!(fast_v2.contains("id=\"webui-data\""));
        assert!(!fast_v2.contains("window.__webui"));
        assert!(!fast_v2.contains(r#""templates""#));
        assert!(!fast_v2.contains("templateFns"));

        let fast_v3 = render(Some(Plugin::FastV3));
        assert!(fast_v3.contains("<!--fe:b-->"));
        assert!(!fast_v3.contains("<!--fe-b$$start$$"));
        assert!(fast_v3.contains("id=\"webui-data\""));
        assert!(!fast_v3.contains("window.__webui"));
        assert!(!fast_v3.contains(r#""templates""#));
        assert!(!fast_v3.contains("templateFns"));
    }

    #[test]
    fn test_build_and_render_without_watch_has_no_hmr_script() {
        let app = create_app_dir(&[("index.html", "<h1>Hello</h1>"), ("state.json", "{}")]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: Some(app.path().join("state.json")),
            token_file: None,
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };
        let BuildRenderResult { html, .. } = build_and_render(&config, None).unwrap();
        assert!(!html.contains(HMR_ENDPOINT));
        assert!(!html.contains("EventSource"));
    }

    #[test]
    fn test_ensure_local_port_available_reports_port_in_use() {
        let listener = TcpListener::bind((Ipv4Addr::LOCALHOST, 0)).unwrap();
        let port = listener.local_addr().unwrap().port();

        let error = ensure_local_port_available(port).unwrap_err();

        assert!(
            format!("{error:#}").contains(&format!("Port {port} on 127.0.0.1 is already in use"))
        );
        drop(listener);
    }

    #[test]
    fn test_build_and_render_missing_state_file() {
        let app = create_app_dir(&[("index.html", "<h1>No State</h1>")]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: Some(app.path().join("state.json")),
            token_file: None,
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };
        let hmr = LiveReload::new(HMR_ENDPOINT);
        let result = build_and_render(&config, Some(&hmr));
        assert!(result.is_err());
    }

    #[test]
    fn test_build_and_render_no_state_file() {
        let app = create_app_dir(&[("index.html", "<h1>Hello</h1>")]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: None,
            token_file: None,
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };
        let result = build_and_render(&config, None).unwrap();
        assert!(result.html.contains("<h1>Hello</h1>"));
    }

    #[test]
    fn test_build_and_render_missing_template() {
        let app = create_app_dir(&[("state.json", "{}")]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: Some(app.path().join("state.json")),
            token_file: None,
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };
        let hmr = LiveReload::new(HMR_ENDPOINT);
        let result = build_and_render(&config, Some(&hmr));
        assert!(result.is_err());
    }

    #[test]
    fn test_build_request_paths_preserves_query_string() {
        assert_eq!(
            build_request_paths("search", "q=shirt&sort=price-desc"),
            RequestPaths {
                route_path: "/search".to_string(),
                request_path: "/search?q=shirt&sort=price-desc".to_string(),
            }
        );
    }

    #[test]
    fn test_build_request_paths_handles_root_query() {
        assert_eq!(
            build_request_paths("", "q=shirt"),
            RequestPaths {
                route_path: "/".to_string(),
                request_path: "/?q=shirt".to_string(),
            }
        );
    }

    #[test]
    fn test_collect_needed_template_names_returns_active_route_payloads() {
        let mut fragments = HashMap::new();
        fragments.insert(
            "index.html".to_string(),
            FragmentList {
                fragments: vec![WebUIFragment::component("mp-app")],
            },
        );
        fragments.insert(
            "mp-app".to_string(),
            FragmentList {
                fragments: vec![
                    WebUIFragment::component("mp-category-nav"),
                    WebUIFragment::route_from(WebUiFragmentRoute {
                        path: "/search/:category".to_string(),
                        fragment_id: "mp-page-search".to_string(),
                        exact: true,
                        keep_alive: false,
                        ..Default::default()
                    }),
                    WebUIFragment::route_from(WebUiFragmentRoute {
                        path: "/product/:handle".to_string(),
                        fragment_id: "mp-page-product".to_string(),
                        exact: true,
                        keep_alive: false,
                        ..Default::default()
                    }),
                ],
            },
        );
        fragments.insert(
            "mp-category-nav".to_string(),
            FragmentList {
                fragments: vec![WebUIFragment::raw("<nav></nav>")],
            },
        );
        fragments.insert(
            "mp-page-search".to_string(),
            FragmentList {
                fragments: vec![WebUIFragment::component("mp-product-grid")],
            },
        );
        fragments.insert(
            "mp-product-grid".to_string(),
            FragmentList {
                fragments: vec![WebUIFragment::raw("<div></div>")],
            },
        );
        fragments.insert(
            "mp-page-product".to_string(),
            FragmentList {
                fragments: vec![WebUIFragment::component("mp-product-detail")],
            },
        );
        fragments.insert(
            "mp-product-detail".to_string(),
            FragmentList {
                fragments: vec![WebUIFragment::raw("<article></article>")],
            },
        );

        let mut protocol = WebUIProtocol::with_tokens(fragments, Vec::new());
        protocol
            .components
            .entry("mp-page-search".to_string())
            .or_default()
            .template = "<f-template id=search></f-template>".to_string();
        protocol
            .components
            .entry("mp-page-product".to_string())
            .or_default()
            .template = "<f-template id=product></f-template>".to_string();
        let (needed, inventory) =
            collect_needed_template_names(&protocol, "index.html", "/search/shirts", "");

        assert_eq!(needed, vec!["mp-page-search".to_string()]);
        assert!(!needed.contains(&"mp-page-product".to_string()));
        assert!(!inventory.is_empty());
    }

    #[actix_web::test]
    async fn test_fetch_api_state_preserves_query_string() {
        let listener = std::net::TcpListener::bind(("127.0.0.1", 0)).unwrap();
        let port = listener.local_addr().unwrap().port();

        let server = HttpServer::new(|| {
            App::new().route(
                "/search",
                web::get().to(|query: web::Query<HashMap<String, String>>| async move {
                    HttpResponse::Ok().json(serde_json::json!({
                        "state": {
                            "query": query.get("q").cloned().unwrap_or_default(),
                            "sort": query.get("sort").cloned().unwrap_or_default(),
                        }
                    }))
                }),
            )
        })
        .listen(listener)
        .unwrap()
        .run();

        let handle = server.handle();
        actix_web::rt::spawn(server);

        let state = fetch_api_state(port, "/search?q=shirt&sort=price-desc")
            .await
            .unwrap();

        assert_eq!(state["query"], "shirt");
        assert_eq!(state["sort"], "price-desc");

        handle.stop(true).await;
    }

    #[actix_web::test]
    async fn test_route_state_fetch_preserves_encoded_request_target() {
        let request_targets = [
            "/projects/WebUI%20Fidelity%20Fixture?filter=space%20value",
            "/reviews/WebUI/ceo%2Fbranch?filter=slash%2Fvalue",
            "/discount/100%25?filter=percent%25value",
            "/city/Montr%C3%A9al?filter=unicode%C3%A9",
        ];
        let (port, handle, captured_targets) = start_request_target_server();
        let app = actix_test::init_service(
            App::new()
                .app_data(test_server_context(port))
                .route("/{tail:.*}", web::get().to(handle_asset)),
        )
        .await;

        for request_target in request_targets {
            let response = actix_test::call_service(
                &app,
                actix_test::TestRequest::get()
                    .uri(request_target)
                    .insert_header(("accept", "application/json"))
                    .to_request(),
            )
            .await;
            assert_eq!(response.status(), StatusCode::OK);
        }

        let expected: Vec<String> = request_targets
            .iter()
            .map(|target| (*target).to_string())
            .collect();
        assert_eq!(*captured_targets.lock().unwrap(), expected);
        handle.stop(true).await;
    }

    fn start_stream_status_server(status: StatusCode) -> (u16, actix_web::dev::ServerHandle) {
        let listener = TcpListener::bind((Ipv4Addr::LOCALHOST, 0)).unwrap();
        let port = listener.local_addr().unwrap().port();
        let server = HttpServer::new(move || {
            App::new().default_service(web::to(move || async move {
                HttpResponse::build(status)
                    .content_type("application/x-webui-stream")
                    .body("streaming render capacity is temporarily exhausted")
            }))
        })
        .listen(listener)
        .unwrap()
        .run();
        let handle = server.handle();
        actix_web::rt::spawn(server);
        (port, handle)
    }

    fn streaming_fallback_context(api_port: u16) -> web::Data<ServerContext> {
        let mut fragments = HashMap::new();
        fragments.insert(
            "index.html".to_string(),
            FragmentList {
                fragments: vec![WebUIFragment::raw(
                    "<html><body><main>fallback rendered</main></body></html>",
                )],
            },
        );
        let protocol = Arc::new(Protocol::new(WebUIProtocol::with_tokens(
            fragments,
            Vec::new(),
        )));
        web::Data::new(ServerContext {
            state: Arc::new(Mutex::new(SharedState {
                rendered_html: String::new(),
                css_files: HashMap::new(),
                component_assets: HashMap::new(),
                protocol: Some(protocol),
                state_data: Some(Value::Object(serde_json::Map::new())),
                token_css: None,
                rebuild_error: None,
                entry: "index.html".to_string(),
            })),
            livereload: None,
            assets_dir: None,
            api_port: Some(api_port),
            plugin: None,
            base_path: None,
            chunk_pool: Arc::new(webui::streaming::ChunkPool::new(
                4,
                StreamingWriter::CHUNK_TARGET + 1024,
            )),
        })
    }

    /// A streaming API that refuses the request never produced a stream, so the
    /// dev server must degrade to a buffered render exactly like it does for a
    /// connection error — not hand the browser a raw upstream error body.
    #[actix_web::test]
    async fn test_streaming_api_error_status_degrades_to_a_rendered_page() {
        for status in [
            StatusCode::SERVICE_UNAVAILABLE,
            StatusCode::INTERNAL_SERVER_ERROR,
            StatusCode::BAD_GATEWAY,
        ] {
            let (port, handle) = start_stream_status_server(status);
            let context = streaming_fallback_context(port);

            let response = render_page_response(&context, "/", "/").await;

            assert_eq!(
                response.status(),
                StatusCode::OK,
                "upstream {status} must not surface as the page status",
            );
            let body = to_bytes(response.into_body()).await.unwrap();
            let body = String::from_utf8_lossy(&body);
            assert!(
                body.contains("fallback rendered"),
                "upstream {status} must still render the page, got: {body}",
            );
            handle.stop(true).await;
        }
    }

    fn fallback_kind_for_accept(accept: &str) -> SpaFallbackKind {
        let req = actix_test::TestRequest::default()
            .insert_header(("accept", accept))
            .to_http_request();
        spa_fallback_kind(&req)
    }

    #[test]
    fn test_spa_fallback_kind_honors_q_weights() {
        let cases = [
            ("application/json;q=0", SpaFallbackKind::None),
            ("text/html;q=0", SpaFallbackKind::None),
            (
                "text/html;q=0.8, application/json;q=0.9",
                SpaFallbackKind::Json,
            ),
            (
                "text/html;q=0.9, application/json;q=0.8",
                SpaFallbackKind::Html,
            ),
            ("text/html;q=1, application/json;q=1", SpaFallbackKind::Json),
            ("application/json", SpaFallbackKind::Json),
            (
                "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
                SpaFallbackKind::Html,
            ),
            ("APPLICATION/JSON ; Q=0.5", SpaFallbackKind::Json),
            ("application/json;q=not-a-number", SpaFallbackKind::Json),
            // Out-of-range q is malformed and falls back to the default 1.0, so
            // it neither wins tie-breaking nor disables the media type.
            ("text/html;q=2, application/json;q=1", SpaFallbackKind::Json),
            ("text/html;q=-1", SpaFallbackKind::Html),
        ];

        for (accept, expected) in cases {
            assert_eq!(fallback_kind_for_accept(accept), expected, "{accept}");
        }
    }

    #[actix_web::test]
    async fn test_spa_fallback_allows_encoded_dot_route_parameter() {
        let request_target = "/discount/100%2E5?filter=x";
        let (port, handle, captured_targets) = start_request_target_server();
        let app = actix_test::init_service(
            App::new()
                .app_data(test_server_context(port))
                .route("/{tail:.*}", web::get().to(handle_asset)),
        )
        .await;

        let response = actix_test::call_service(
            &app,
            actix_test::TestRequest::get()
                .uri(request_target)
                .insert_header(("accept", "application/json"))
                .to_request(),
        )
        .await;
        assert_eq!(response.status(), StatusCode::OK);

        let captured = match captured_targets.lock() {
            Ok(targets) => targets.clone(),
            Err(error) => panic!("captured targets mutex poisoned: {error}"),
        };
        assert_eq!(captured, vec![request_target.to_string()]);
        handle.stop(true).await;
    }

    #[actix_web::test]
    async fn test_spa_fallback_allows_literal_dot_html_route() {
        let app = actix_test::init_service(
            App::new()
                .app_data(test_route_context(dotted_route_protocol()))
                .route("/{tail:.*}", web::get().to(handle_asset)),
        )
        .await;

        let response = actix_test::call_service(
            &app,
            actix_test::TestRequest::get()
                .uri("/docs/v2.1")
                .insert_header(("accept", "text/html,application/xhtml+xml"))
                .to_request(),
        )
        .await;

        assert_eq!(response.status(), StatusCode::OK);
    }

    #[actix_web::test]
    async fn test_spa_fallback_rejects_missing_asset_intent() {
        let app = actix_test::init_service(
            App::new()
                .app_data(test_route_context(dotted_route_protocol()))
                .route("/{tail:.*}", web::get().to(handle_asset)),
        )
        .await;

        let response = actix_test::call_service(
            &app,
            actix_test::TestRequest::get()
                .uri("/missing.js")
                .insert_header(("accept", "text/javascript,*/*;q=0.1"))
                .to_request(),
        )
        .await;
        assert_eq!(response.status(), StatusCode::NOT_FOUND);

        let response = actix_test::call_service(
            &app,
            actix_test::TestRequest::get()
                .uri("/users/john.doe")
                .insert_header(("accept", "*/*"))
                .to_request(),
        )
        .await;
        assert_eq!(response.status(), StatusCode::NOT_FOUND);

        let response = actix_test::call_service(
            &app,
            actix_test::TestRequest::get()
                .uri("/docs/v2.1")
                .to_request(),
        )
        .await;
        assert_eq!(response.status(), StatusCode::NOT_FOUND);
    }

    #[actix_web::test]
    async fn test_api_proxy_preserves_encoded_request_target() {
        let request_targets = [
            "/api/projects/WebUI%20Fidelity%20Fixture?filter=space%20value",
            "/api/reviews/WebUI/ceo%2Fbranch?filter=slash%2Fvalue",
            "/api/discount/100%25?filter=percent%25value",
            "/api/city/Montr%C3%A9al?filter=unicode%C3%A9",
        ];
        let (port, handle, captured_targets) = start_request_target_server();
        let app = actix_test::init_service(
            App::new()
                .app_data(test_server_context(port))
                .route("/api/{tail:.*}", web::route().to(handle_api_proxy)),
        )
        .await;

        for request_target in request_targets {
            let response = actix_test::call_service(
                &app,
                actix_test::TestRequest::get()
                    .uri(request_target)
                    .to_request(),
            )
            .await;
            assert_eq!(response.status(), StatusCode::OK);
        }

        let expected: Vec<String> = request_targets
            .iter()
            .map(|target| (*target).to_string())
            .collect();
        assert_eq!(*captured_targets.lock().unwrap(), expected);
        handle.stop(true).await;
    }

    #[test]
    fn test_hmr_script_is_injected_when_livereload_present() {
        let app = create_app_dir(&[("index.html", "<h1>Hi</h1>"), ("state.json", "{}")]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: Some(app.path().join("state.json")),
            token_file: None,
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };
        let lr = LiveReload::new(HMR_ENDPOINT);
        let BuildRenderResult { html, .. } = build_and_render(&config, Some(&lr)).unwrap();
        // The injected SSE bootstrap should reference the endpoint.
        assert!(html.contains(HMR_ENDPOINT));
        assert!(html.contains("EventSource"));
    }

    #[test]
    fn test_watch_paths_excludes_servedir() {
        // serve_dir is intentionally NOT watched: it is the destination
        // for client bundles written by other tools (esbuild, pnpm,
        // E2E harness). Watching it would cause spurious livereload
        // broadcasts during E2E runs.
        let dir = create_app_dir(&[("state.json", "{}"), ("public/x.css", "")]);
        let paths = ServePaths {
            app_dir: dir.path().to_path_buf(),
            state_file: Some(dir.path().join("state.json")),
            serve_dir: Some(dir.path().join("public")),
            metafile: None,
        };
        let watched = paths.watch_paths();
        assert_eq!(watched.len(), 2);
        assert!(watched.contains(&dir.path().to_path_buf()));
        assert!(watched.contains(&dir.path().join("state.json")));
        assert!(!watched.contains(&dir.path().join("public")));
    }

    #[test]
    fn test_build_and_render_hello_world_example() {
        let manifest_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
        let app_dir = manifest_dir.join("../../examples/app/hello-world/src");
        let config = RenderConfig {
            app_args: AppArgs {
                app: app_dir.clone(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir,
            state_file: Some(manifest_dir.join("../../examples/app/hello-world/data/state.json")),
            token_file: None,
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };
        let lr = LiveReload::new(HMR_ENDPOINT);
        let BuildRenderResult { html, .. } = build_and_render(&config, Some(&lr)).unwrap();
        assert!(html.contains("Hello, WebUI!"));
        assert!(html.contains("Ali"));
        assert!(html.contains("Mohamed Mansour"));
        // HMR script should be injected
        assert!(html.contains(HMR_ENDPOINT));
    }

    #[actix_web::test]
    async fn test_route_precedence_over_asset_catch_all() {
        let livereload = LiveReload::new(HMR_ENDPOINT);
        let lr_endpoint = livereload.endpoint().to_string();
        let context = web::Data::new(ServerContext {
            state: Arc::new(Mutex::new(SharedState {
                rendered_html: "<html><body>ok</body></html>".to_string(),
                css_files: HashMap::new(),
                component_assets: HashMap::new(),
                protocol: None,
                state_data: None,
                token_css: None,
                rebuild_error: None,
                entry: "index.html".to_string(),
            })),
            livereload: Some(livereload.clone()),
            assets_dir: None,
            api_port: None,
            plugin: None,
            base_path: None,
            chunk_pool: Arc::new(webui::streaming::ChunkPool::new(
                4,
                StreamingWriter::CHUNK_TARGET + 1024,
            )),
        });

        let app = actix_test::init_service(
            App::new()
                .app_data(context.clone())
                .app_data(web::Data::new(livereload))
                .route("/", web::get().to(handle_index))
                .route("/index.html", web::get().to(handle_index))
                .route(&lr_endpoint, web::get().to(sse_handler))
                .route("/{tail:.*}", web::get().to(handle_asset))
                .default_service(web::route().to(handle_not_found)),
        )
        .await;

        // SSE endpoint takes precedence over the catch-all asset route.
        let lr_response = actix_test::call_service(
            &app,
            actix_test::TestRequest::get()
                .uri(HMR_ENDPOINT)
                .to_request(),
        )
        .await;
        assert_eq!(lr_response.status(), StatusCode::OK);
        let content_type = lr_response
            .headers()
            .get("content-type")
            .map(|v| v.to_str().unwrap_or("").to_string())
            .unwrap_or_default();
        assert!(
            content_type.starts_with("text/event-stream"),
            "expected SSE content-type, got {content_type:?}"
        );

        let index_response = actix_test::call_service(
            &app,
            actix_test::TestRequest::get()
                .uri("/index.html")
                .to_request(),
        )
        .await;
        assert_eq!(index_response.status(), StatusCode::OK);

        let index_body = actix_test::read_body(index_response).await;
        assert_eq!(
            index_body,
            web::Bytes::from_static(b"<html><body>ok</body></html>")
        );
    }

    #[actix_web::test]
    async fn test_refresh_after_rebuild_error_reports_error_instead_of_stale_html() {
        let livereload = LiveReload::new(HMR_ENDPOINT);
        let context = web::Data::new(ServerContext {
            state: Arc::new(Mutex::new(SharedState {
                rendered_html: "<html><body>stale ok</body></html>".to_string(),
                css_files: HashMap::new(),
                component_assets: HashMap::new(),
                protocol: None,
                state_data: None,
                token_css: None,
                rebuild_error: Some(
                    "missing theme token [missing-theme-token]\n    --token-c".to_string(),
                ),
                entry: "index.html".to_string(),
            })),
            livereload: Some(livereload),
            assets_dir: None,
            api_port: None,
            plugin: None,
            base_path: None,
            chunk_pool: Arc::new(webui::streaming::ChunkPool::new(
                4,
                StreamingWriter::CHUNK_TARGET + 1024,
            )),
        });

        let app = actix_test::init_service(
            App::new()
                .app_data(context)
                .route("/", web::get().to(handle_index)),
        )
        .await;

        let response =
            actix_test::call_service(&app, actix_test::TestRequest::get().uri("/").to_request())
                .await;

        assert_eq!(response.status(), StatusCode::INTERNAL_SERVER_ERROR);
        let body = String::from_utf8(actix_test::read_body(response).await.to_vec()).unwrap();
        assert!(body.contains("missing-theme-token"), "body: {body}");
        assert!(body.contains("--token-c"), "body: {body}");
        assert!(body.contains("EventSource"), "body: {body}");
        assert!(body.contains(HMR_ENDPOINT), "body: {body}");
        assert!(!body.contains("stale ok"), "body: {body}");
    }

    #[actix_web::test]
    async fn test_json_partial_rebuild_error_skips_api_state_fetch() {
        let api_hits = Arc::new(AtomicUsize::new(0));
        let api_hits_for_server = Arc::clone(&api_hits);
        let listener = std::net::TcpListener::bind(("127.0.0.1", 0)).unwrap();
        let port = listener.local_addr().unwrap().port();
        let server = HttpServer::new(move || {
            let api_hits = Arc::clone(&api_hits_for_server);
            App::new().default_service(web::to(move || {
                let api_hits = Arc::clone(&api_hits);
                async move {
                    api_hits.fetch_add(1, Ordering::SeqCst);
                    HttpResponse::Ok()
                        .content_type("application/json")
                        .body(r#"{"state":{"name":"api"}}"#)
                }
            }))
        })
        .listen(listener)
        .unwrap()
        .run();
        let handle = server.handle();
        actix_web::rt::spawn(server);

        let context = web::Data::new(ServerContext {
            state: Arc::new(Mutex::new(SharedState {
                rendered_html: "<html><body>stale ok</body></html>".to_string(),
                css_files: HashMap::new(),
                component_assets: HashMap::new(),
                protocol: None,
                state_data: None,
                token_css: None,
                rebuild_error: Some(
                    "missing theme token [missing-theme-token]\n    --token-c".to_string(),
                ),
                entry: "index.html".to_string(),
            })),
            livereload: None,
            assets_dir: None,
            api_port: Some(port),
            plugin: None,
            base_path: None,
            chunk_pool: Arc::new(webui::streaming::ChunkPool::new(
                4,
                StreamingWriter::CHUNK_TARGET + 1024,
            )),
        });

        let app = actix_test::init_service(
            App::new()
                .app_data(context)
                .route("/", web::get().to(handle_index)),
        )
        .await;
        let response = actix_test::call_service(
            &app,
            actix_test::TestRequest::get()
                .uri("/")
                .insert_header(("accept", "application/json"))
                .to_request(),
        )
        .await;

        assert_eq!(response.status(), StatusCode::INTERNAL_SERVER_ERROR);
        let body = String::from_utf8(actix_test::read_body(response).await.to_vec()).unwrap();
        assert!(body.contains("missing-theme-token"), "body: {body}");
        assert_eq!(api_hits.load(Ordering::SeqCst), 0);
        handle.stop(true).await;
    }

    #[actix_web::test]
    async fn test_html_render_rebuild_error_skips_api_state_fetch() {
        // An HTML (non-JSON) request with an API proxy configured must return
        // the stored rebuild error from the single state snapshot, without
        // reaching out to the API server first.
        let api_hits = Arc::new(AtomicUsize::new(0));
        let api_hits_for_server = Arc::clone(&api_hits);
        let listener = std::net::TcpListener::bind(("127.0.0.1", 0)).unwrap();
        let port = listener.local_addr().unwrap().port();
        let server = HttpServer::new(move || {
            let api_hits = Arc::clone(&api_hits_for_server);
            App::new().default_service(web::to(move || {
                let api_hits = Arc::clone(&api_hits);
                async move {
                    api_hits.fetch_add(1, Ordering::SeqCst);
                    HttpResponse::Ok()
                        .content_type("application/json")
                        .body(r#"{"state":{"name":"api"}}"#)
                }
            }))
        })
        .listen(listener)
        .unwrap()
        .run();
        let handle = server.handle();
        actix_web::rt::spawn(server);

        let context = web::Data::new(ServerContext {
            state: Arc::new(Mutex::new(SharedState {
                rendered_html: "<html><body>stale ok</body></html>".to_string(),
                css_files: HashMap::new(),
                component_assets: HashMap::new(),
                protocol: None,
                state_data: None,
                token_css: None,
                rebuild_error: Some(
                    "missing theme token [missing-theme-token]\n    --token-c".to_string(),
                ),
                entry: "index.html".to_string(),
            })),
            livereload: None,
            assets_dir: None,
            api_port: Some(port),
            plugin: None,
            base_path: None,
            chunk_pool: Arc::new(webui::streaming::ChunkPool::new(
                4,
                StreamingWriter::CHUNK_TARGET + 1024,
            )),
        });

        let app = actix_test::init_service(
            App::new()
                .app_data(context)
                .route("/", web::get().to(handle_index)),
        )
        .await;
        let response =
            actix_test::call_service(&app, actix_test::TestRequest::get().uri("/").to_request())
                .await;

        assert_eq!(response.status(), StatusCode::INTERNAL_SERVER_ERROR);
        let body = String::from_utf8(actix_test::read_body(response).await.to_vec()).unwrap();
        assert!(body.contains("missing-theme-token"), "body: {body}");
        assert!(!body.contains("stale ok"), "body: {body}");
        assert_eq!(api_hits.load(Ordering::SeqCst), 0);
        handle.stop(true).await;
    }

    #[test]
    fn test_incremental_rebuild_failure_persists_error_for_refresh() {
        let app = create_app_dir(&[
            ("index.html", "<my-card></my-card>"),
            ("my-card.html", "<div>Card</div>"),
            (
                "my-card.css",
                ":host { --token-a: red; --foo-bar: var(--token-a, var(--token-b, var(--token-c))); }",
            ),
        ]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: None,
            token_file: Some(webui::TokenFile {
                themes: HashMap::from([(
                    "light".to_string(),
                    HashMap::from([("token-b".to_string(), "green".to_string())]),
                )]),
            }),
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };
        let state = Arc::new(Mutex::new(SharedState {
            rendered_html: "<html><body>stale ok</body></html>".to_string(),
            css_files: HashMap::new(),
            component_assets: HashMap::new(),
            protocol: None,
            state_data: None,
            token_css: None,
            rebuild_error: None,
            entry: "index.html".to_string(),
        }));
        let livereload = LiveReload::new(HMR_ENDPOINT);

        let result = rebuild_and_update_state(&config, &livereload, &state);

        assert!(result.is_err(), "missing token should fail rebuild");
        let error = state.lock().unwrap().rebuild_error.clone().unwrap();
        assert!(error.contains("missing-theme-token"), "error: {error}");
        assert!(error.contains("--token-c"), "error: {error}");
        // The error demands the missing `--token-c`, not the locally-defined
        // `--token-a` (which appears in the source snippet only as context).
        assert!(!error.contains("add --token-a"), "error: {error}");

        std::fs::write(
            app.path().join("my-card.css"),
            ":host { --foo-bar: var(--token-b); }",
        )
        .unwrap();
        assert!(
            rebuild_and_update_state(&config, &livereload, &state).is_ok(),
            "a later valid synchronization file must recover the rebuild loop"
        );
        assert!(state.lock().unwrap().rebuild_error.is_none());
    }

    #[test]
    fn test_incremental_rebuild_returns_theme_token_warnings() {
        // A literal-fallback token absent from the theme is a non-fatal
        // advisory; the rebuild succeeds and the worker is handed the warnings
        // to print under the "rebuilt" line.
        let app = create_app_dir(&[
            ("index.html", "<my-card></my-card>"),
            ("my-card.html", "<div>Card</div>"),
            ("my-card.css", ":host { color: var(--colr-brand, #000); }"),
        ]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: None,
            token_file: Some(webui::TokenFile {
                themes: HashMap::from([(
                    "light".to_string(),
                    HashMap::from([("color-brand".to_string(), "#abc".to_string())]),
                )]),
            }),
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };
        let state = Arc::new(Mutex::new(SharedState {
            rendered_html: String::new(),
            css_files: HashMap::new(),
            component_assets: HashMap::new(),
            protocol: None,
            state_data: None,
            token_css: None,
            rebuild_error: None,
            entry: "index.html".to_string(),
        }));
        let livereload = LiveReload::new(HMR_ENDPOINT);

        let warnings = match rebuild_and_update_state(&config, &livereload, &state) {
            Ok(warnings) => warnings,
            Err(_) => panic!("literal-fallback typo must not fail the rebuild"),
        };
        assert_eq!(warnings.len(), 1, "warnings: {warnings:?}");
        assert!(
            warnings[0].body().contains("--colr-brand"),
            "warning: {}",
            warnings[0].body()
        );
        assert!(
            warnings[0].body().contains("did you mean --color-brand?"),
            "warning: {}",
            warnings[0].body()
        );
        assert!(state.lock().unwrap().rebuild_error.is_none());
    }

    #[test]
    fn test_build_and_render_trusts_theme_token_dependencies() {
        // `--brand` is optional because the CSS has a literal fallback. When a
        // theme defines it, serve should inject that value as-is and trust the
        // theme instead of failing on its internal `var(--missing)` reference.
        let app = create_app_dir(&[
            ("index.html", "<my-card></my-card>"),
            ("my-card.html", "<div>Card</div>"),
            ("my-card.css", ":host { color: var(--brand, #000); }"),
        ]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: None,
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: None,
            token_file: Some(webui::TokenFile {
                themes: HashMap::from([(
                    "light".to_string(),
                    HashMap::from([("brand".to_string(), "var(--missing)".to_string())]),
                )]),
            }),
            component_asset_roots: Vec::new(),
            metafile: None,
            base_path: None,
        };

        let result = build_and_render(&config, None).unwrap();
        let token_css = result.token_css.expect("resolved token css");
        assert_eq!(token_css["light"], "--brand: var(--missing);");
        assert!(
            result.warnings.is_empty(),
            "warnings: {:?}",
            result.warnings
        );
    }

    #[test]
    fn test_build_and_render_emits_component_asset_into_memory() {
        // `--emit-component-assets` parity: serve compiles the static asset and
        // keeps it in memory (served like generated CSS), no `--out` needed.
        let app = create_app_dir(&[
            ("index.html", "<app-shell></app-shell>"),
            ("app-shell.html", "<div></div>"),
            ("lazy-panel.html", "<p>{{title}}</p>"),
            ("lazy-panel.css", ":host { color: red; }"),
            ("lazy-panel.ts", "export {};"),
        ]);
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: Some(Plugin::WebUI),
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: None,
            token_file: None,
            component_asset_roots: vec!["lazy-panel".to_string()],
            metafile: None,
            base_path: None,
        };
        let result = build_and_render(&config, None).unwrap();
        let asset = result
            .component_assets
            .get("lazy-panel.webui.js")
            .unwrap_or_else(|| {
                panic!(
                    "expected lazy-panel.webui.js; got {:?}",
                    result.component_assets.keys().collect::<Vec<_>>()
                )
            });
        assert!(asset.contains("webui-component-asset"), "asset: {asset}");
    }

    #[test]
    fn test_successful_rebuild_replaces_metafile_and_failure_preserves_it() {
        let app = create_app_dir(&[
            ("index.html", "<app-shell></app-shell>"),
            ("app-shell.html", "<div></div>"),
            ("lazy-panel.html", "<p>First</p>"),
        ]);
        let metafile = app.path().join("component-assets.meta.json");
        let config = RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: Some(Plugin::WebUI),
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: None,
            token_file: None,
            component_asset_roots: vec!["lazy-panel".to_string()],
            metafile: Some(metafile.clone()),
            base_path: None,
        };

        build_and_render(&config, None).unwrap();
        let first = fs::read_to_string(&metafile).unwrap();
        fs::write(
            app.path().join("lazy-panel.html"),
            "<p>Second and larger</p>",
        )
        .unwrap();
        build_and_render(&config, None).unwrap();
        let second = fs::read_to_string(&metafile).unwrap();
        assert_ne!(first, second);

        fs::write(
            app.path().join("lazy-panel.html"),
            r#"<if condition="ready"><p>Broken</if>"#,
        )
        .unwrap();
        assert!(build_and_render(&config, None).is_err());
        assert_eq!(fs::read_to_string(&metafile).unwrap(), second);
        let ignored = watcher_ignore_paths(Some(&metafile));
        assert!(ignored.contains(&metafile::watch_ignore_paths(&metafile)[1]));
        assert!(!metafile_temp_directory(&metafile).exists());
        assert!(
            fs::read_dir(app.path()).unwrap().all(|entry| !entry
                .unwrap()
                .file_name()
                .to_string_lossy()
                .ends_with(".tmp")),
            "atomic writes must not leave temporary files"
        );
    }

    #[test]
    fn test_component_asset_root_css_token_error_fails_dev_build() {
        // The dev-server blind spot this feature closes: a theme-token error in
        // a lazily loaded component (absent from the SSR tree) must fail the
        // build — but only because it is an `--emit-component-assets` root.
        // Without the root, the component is discovered but never parsed, so
        // its CSS tokens are never validated (the bug). With the root, they are.
        let app = create_app_dir(&[
            ("index.html", "<app-shell></app-shell>"),
            ("app-shell.html", "<div></div>"),
            ("lazy-panel.html", "<p>Panel</p>"),
            ("lazy-panel.css", ":host { color: var(--brand-missing); }"),
        ]);
        let make_config = |roots: Vec<String>| RenderConfig {
            app_args: AppArgs {
                app: app.path().to_path_buf(),
                entry: "index.html".to_string(),
                css: CssStrategy::Link,
                dom: DomStrategy::Shadow,
                plugin: Some(Plugin::WebUI),
                components: Vec::new(),
                projection_manifests: Vec::new(),
                asset_file_name_template: DEFAULT_ASSET_FILE_NAME_TEMPLATE.to_string(),
                css_public_base: None,
                legal_comments: LegalComments::Inline,
            },
            app_dir: app.path().to_path_buf(),
            state_file: None,
            token_file: Some(webui::TokenFile {
                themes: HashMap::from([(
                    "light".to_string(),
                    HashMap::from([("brand-other".to_string(), "#000".to_string())]),
                )]),
            }),
            component_asset_roots: roots,
            metafile: None,
            base_path: None,
        };

        // Not an asset root → lazy-panel is never parsed → build is green.
        assert!(
            build_and_render(&make_config(Vec::new()), None).is_ok(),
            "unreferenced non-root component must not be validated"
        );

        // As an asset root → its missing theme token fails the build.
        let err = build_and_render(&make_config(vec!["lazy-panel".to_string()]), None)
            .err()
            .expect("missing theme token in asset root must fail the build");
        let message = format!("{err:#}");
        assert!(
            message.contains("missing-theme-token"),
            "message: {message}"
        );
        assert!(message.contains("--brand-missing"), "message: {message}");
    }

    #[actix_web::test]
    async fn test_handle_asset_serves_component_asset_from_memory() {
        // In-memory component assets are served with a JS MIME type (the
        // framework loads them via dynamic `import()`), taking precedence over
        // `--servedir`.
        let context = web::Data::new(ServerContext {
            state: Arc::new(Mutex::new(SharedState {
                rendered_html: String::new(),
                css_files: HashMap::new(),
                component_assets: HashMap::from([(
                    "lazy-panel.webui.js".to_string(),
                    "export default {\"type\":\"webui-component-asset\"};".to_string(),
                )]),
                protocol: None,
                state_data: None,
                token_css: None,
                rebuild_error: None,
                entry: "index.html".to_string(),
            })),
            livereload: None,
            assets_dir: None,
            api_port: None,
            plugin: None,
            base_path: None,
            chunk_pool: Arc::new(webui::streaming::ChunkPool::new(
                4,
                StreamingWriter::CHUNK_TARGET + 1024,
            )),
        });

        let app = actix_test::init_service(
            App::new()
                .app_data(context)
                .route("/{tail:.*}", web::get().to(handle_asset)),
        )
        .await;

        let response = actix_test::call_service(
            &app,
            actix_test::TestRequest::get()
                .uri("/lazy-panel.webui.js")
                .to_request(),
        )
        .await;

        assert_eq!(response.status(), StatusCode::OK);
        let content_type = response
            .headers()
            .get("content-type")
            .map(|v| v.to_str().unwrap_or("").to_string())
            .unwrap_or_default();
        assert!(
            content_type.starts_with("text/javascript"),
            "expected JS content-type, got {content_type:?}"
        );
        let body = actix_test::read_body(response).await;
        assert!(
            body.starts_with(b"export default"),
            "unexpected asset body: {body:?}"
        );
    }
}