please make the serve_html function missing here:

#![allow(warnings)]
use base64::encode;
use notify::Watcher;
use std::fs::File;
use std::io::{self, Read, Write};
use std::path::PathBuf;

use clap::Parser;
use pulldown_cmark::{html, Event, Options, Parser as MdParser};
use tokio::sync::{broadcast, RwLock};
use warp::Filter;

use std::sync::Arc;

#[derive(Parser, Debug)]
#[command(author, version, about, long_about = None)]
struct Args {
    #[arg(value_name = "FILE")]
    file: Option<PathBuf>,

    #[arg(short, long)]
    static_mode: bool,
}

#[tokio::main]
async fn main() -> io::Result<()> {
    // Parse command-line arguments
    let args = Args::parse();

    if args.static_mode {
        run_static_mode(&args)?;
    } else {
        run_server_mode(&args).await?;
    }

    Ok(())
}

fn run_static_mode(args: &Args) -> io::Result<()> {
    // Read Markdown content
    let (file_name, markdown_input) = match &args.file {
        Some(file_path) => {
            let mut file = File::open(&file_path).unwrap_or_else(|err| {
                eprintln!("Error opening file {}: {}", file_path.display(), err);
                std::process::exit(1);
            });
            let mut content = String::new();
            file.read_to_string(&mut content)?;
            (
                file_path.file_name().unwrap().to_string_lossy().to_string(),
                content,
            )
        }
        None => {
            // Read from stdin if no file is provided
            let mut content = String::new();
            io::stdin().read_to_string(&mut content)?;
            (String::from("New file"), content)
        }
    };

    let html_output = render_markdown_to_html(&markdown_input);
    let style = read_style_css();
    let fonts = read_fonts();
    let html_content = build_full_html(&file_name, &html_output, &style, &fonts, false);

    // Create a temporary file with .html extension
    let temp_file = tempfile::Builder::new()
        .prefix("markdown_preview_")
        .suffix(".html")
        .rand_bytes(5)
        .tempfile()?;
    let temp_path = temp_file.path().to_string_lossy().to_string();

    // Write HTML content to the temporary file
    let mut file = temp_file.as_file();
    file.write_all(html_content.as_bytes())?;
    file.flush()?;

    // Open the default browser
    #[cfg(target_os = "macos")]
    {
        std::process::Command::new("open")
            .arg(&temp_path)
            .spawn()
            .expect("Failed to open browser");
    }
    #[cfg(target_os = "windows")]
    {
        std::process::Command::new("cmd")
            .args(&["/C", "start", &temp_path])
            .spawn()
            .expect("Failed to open browser");
    }
    #[cfg(target_os = "linux")]
    {
        std::process::Command::new("xdg-open")
            .arg(&temp_path)
            .spawn()
            .expect("Failed to open browser");
    }
    // Keep the program running to prevent the temporary file from being deleted
    println!("Press Enter to exit...");
    let mut input = String::new();
    io::stdin().read_line(&mut input)?;

    Ok(())
}

async fn run_server_mode(args: &Args) -> io::Result<()> {
    let file_path = match &args.file {
        Some(path) => path.clone(),
        None => {
            eprintln!("Error: No input file specified in server mode.");
            std::process::exit(1);
        }
    };

    let file_name = file_path.file_name().unwrap().to_string_lossy().to_string();

    let markdown_input = read_markdown_input(&file_path)?;
    let html_output = render_markdown_to_html(&markdown_input);
    let style = read_style_css();
    let fonts = read_fonts();

    let (tx, rx) = broadcast::channel::<()>(100);
    let app_state = Arc::new(AppState {
        html_content: Arc::new(RwLock::new(html_output)),
        css_content: style,
        fonts,
        file_path: file_path.clone(),
        notifier: tx.clone(),
        file_name,
    });

    // Start the file watcher task
    let app_state_clone = app_state.clone();
    tokio::task::spawn_blocking(move || watch_markdown_file(app_state_clone));

    // Set up the routes
    let state_filter = warp::any().map(move || app_state.clone());

    let html_route = warp::path::end()
        .and(state_filter.clone())
        .and_then(serve_html);

    let sse_route = warp::path("events")
        .and(warp::sse())
        .and(state_filter.clone())
        .and_then(sse_handler);

    println!("Server running at http://localhost:3030/");
    if let Err(e) = warp::serve(html_route.or(sse_route))
        .run(([127, 0, 0, 1], 3030))
        .await
    {
        eprintln!("Server error: {:?}", e);
    }

    Ok(())
}

fn read_markdown_input(file_path: &PathBuf) -> io::Result<String> {
    let mut file = File::open(&file_path)?;
    let mut content = String::new();
    file.read_to_string(&mut content)?;
    Ok(content)
}

fn render_markdown_to_html(markdown_input: &str) -> String {
    let mut options = Options::empty();
    options.insert(Options::ENABLE_STRIKETHROUGH);
    options.insert(Options::ENABLE_TABLES);
    options.insert(Options::ENABLE_FOOTNOTES);
    options.insert(Options::ENABLE_TASKLISTS);
    options.insert(Options::ENABLE_SMART_PUNCTUATION);

    let parser = MdParser::new_ext(&markdown_input, options);
    let mut html_output = String::new();
    html::push_html(
        &mut html_output,
        parser.map(|event| match event {
            Event::SoftBreak => Event::Html("<br>".into()),
            _ => event,
        }),
    );
    html_output
}

fn read_style_css() -> String {
    let default_css = r#"
        body { font-family: Arial, sans-serif; line-height: 1.6; padding: 20px; max-width: 800px; margin: 0 auto; }
        pre { background-color: #f4f4f4; padding: 10px; border-radius: 5px; }
        code { background-color: #f4f4f4; padding: 2px 4px; border-radius: 3px; }
    "#
    .to_string();

    let mut contents = String::new();

    // Try to open and read the file
    if let Ok(mut file) = File::open("./src/style.css") {
        if let Err(_) = file.read_to_string(&mut contents) {
            // If reading the file fails, use default CSS
            contents = default_css;
        }
    } else {
        // If opening the file fails, use default CSS
        contents = default_css;
    }

    contents
}

struct Fonts {
    font_regular: String,
    font_medium: String,
    font_light: String,
    favicon: String,
}

fn read_fonts() -> Fonts {
    Fonts {
        font_regular: encode(include_bytes!("./fonts/Oswald/Oswald-Regular.ttf")),
        font_medium: encode(include_bytes!("./fonts/Oswald/Oswald-Regular.ttf")),
        font_light: encode(include_bytes!("./fonts/Oswald/Oswald-Light.ttf")),
        favicon: encode(include_bytes!("./favicon.ico")),
    }
}

struct AppState {
    html_content: Arc<RwLock<String>>,
    css_content: String,
    fonts: Fonts,
    file_path: PathBuf,
    notifier: broadcast::Sender<()>,
    file_name: String,
}

fn watch_markdown_file(app_state: Arc<AppState>) {
    use notify::{Config, RecommendedWatcher, RecursiveMode};
    use std::sync::mpsc::channel;

    let (tx, rx) = channel();
    let mut watcher = RecommendedWatcher::new(tx, Config::default()).unwrap();
    watcher.watch(app_state.file_path.as_path(), RecursiveMode::NonRecursive);

    for res in rx {
        match res {
            Err(errr) => println!("{:?}", errr),
            Ok(_) => println!("success!"),
        }
    }
}

async fn sse_handler(app_state: Arc<AppState>) -> Result<impl warp::Reply, warp::Rejection> {
    let mut rx = app_state.notifier.subscribe();

    // Explicitly annotate the stream's item type
    let event_stream = async_stream::stream! {
        while let Ok(_) = rx.recv().await {
            yield Ok::<_, warp::Error>(warp::sse::Event::default().data("reload"));
        }
    };

    // Now warp::sse::reply will accept the stream as a TryStream
    Ok(warp::sse::reply(
        warp::sse::keep_alive().stream(event_stream),
    ))
}

fn build_full_html(
    file_name: &str,
    html_output: &str,
    style: &str,
    fonts: &Fonts,
    enable_reload: bool,
) -> String {
    let reload_script = if enable_reload {
        r#"
        <script>
            var evtSource = new EventSource("/events");
            evtSource.onmessage = function(e) {
                if (e.data === "reload") {
                    location.reload();
                }
            };
        </script>
        "#
    } else {
        ""
    };

    format!(
        r#"
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="icon" href="data:image/x-icon;base64,{}">
    <style>
        @font-face {{
            font-family: 'Oswald';
            src: url(data:font/truetype;charset=utf-8;base64,{}) format('truetype');
            font-weight: 400;
            font-style: normal;
        }}
        @font-face {{
            font-family: 'Oswald';
            src: url(data:font/truetype;charset=utf-8;base64,{}) format('truetype');
            font-weight: 700;
            font-style: normal;
        }}
        @font-face {{
            font-family: 'Oswald';
            src: url(data:font/truetype;charset=utf-8;base64,{}) format('truetype');
            font-weight: 300;
            font-style: normal;
        }}
        {}
    </style>
    <title>
        {}
    </title>
</head>
<body>
    {}
    {}
</body>
</html>
"#,
        fonts.favicon,
        fonts.font_regular,
        fonts.font_medium,
        fonts.font_light,
        style,
        file_name,
        html_output,
        reload_script
    )
}