poem-http-common 0.4.0

use std::marker::PhantomData;

use poem::{
    http::{header, Method, StatusCode},
    Endpoint, Error, Request, Response,
};
use rust_embed::RustEmbed;

/// An endpoint that wraps a single file from a `rust-embed` bundle.
pub struct EmbeddedFileEndpoint<E: RustEmbed + Send + Sync> {
    _embed: PhantomData<E>,
    path: String,
}

impl<E: RustEmbed + Send + Sync> EmbeddedFileEndpoint<E> {
    /// Create a new `EmbeddedFileEndpoint` from a `rust-embed` bundle.
    ///
    /// `path` - relative path within the bundle.
    pub fn new(path: &str) -> Self {
        EmbeddedFileEndpoint {
            _embed: PhantomData,
            path: path.to_owned(),
        }
    }
}

impl<E: RustEmbed + Send + Sync> Endpoint for EmbeddedFileEndpoint<E> {
    type Output = Response;

    async fn call(&self, req: Request) -> Result<Self::Output, Error> {
        if req.method() != Method::GET {
            return Err(StatusCode::METHOD_NOT_ALLOWED.into());
        }

        match E::get(&self.path) {
            Some(content) => {
                let hash = hex::encode(content.metadata.sha256_hash());
                if req
                    .headers()
                    .get(header::IF_NONE_MATCH)
                    .map(|etag| etag.to_str().unwrap_or("000000").eq(&hash))
                    .unwrap_or(false)
                {
                    return Err(StatusCode::NOT_MODIFIED.into());
                }

                // otherwise, return 200 with etag hash
                let body: Vec<u8> = content.data.into();
                let mime = mime_guess::from_path(&self.path).first_or_octet_stream();
                Ok(Response::builder()
                    .header(header::CONTENT_TYPE, mime.as_ref())
                    .header(header::ETAG, hash)
                    .body(body))
            }
            None => Err(StatusCode::NOT_FOUND.into()),
        }
    }
}

/// An endpoint that wraps a `rust-embed` bundle.
pub struct EmbeddedFilesEndpoint<E: RustEmbed + Send + Sync> {
    _embed: PhantomData<E>,
}

impl<E: RustEmbed + Sync + Send> Default for EmbeddedFilesEndpoint<E> {
    #[inline]
    fn default() -> Self {
        Self::new()
    }
}

impl<E: RustEmbed + Send + Sync> EmbeddedFilesEndpoint<E> {
    /// Create a new `EmbeddedFilesEndpoint` from a `rust-embed` bundle.
    pub fn new() -> Self {
        EmbeddedFilesEndpoint { _embed: PhantomData }
    }
}

impl<E: RustEmbed + Send + Sync> Endpoint for EmbeddedFilesEndpoint<E> {
    type Output = Response;

    async fn call(&self, req: Request) -> Result<Self::Output, Error> {
        let path = req.uri().path().trim_start_matches('/');
        let original_path = req.original_uri().path();
        let original_end_with_slash = original_path.ends_with('/');

        use header::LOCATION;

        log::info!("path: {}", path);

        if path.is_empty() && !original_end_with_slash {
            Ok(Response::builder()
                .status(StatusCode::FOUND)
                .header(LOCATION, format!("{}/", original_path))
                .finish())
        } else if original_end_with_slash {
            let path = format!("{}index.html", path);
            EmbeddedFileEndpoint::<E>::new(&path).call(req).await
        } else if E::get(path).is_some() {
            EmbeddedFileEndpoint::<E>::new(path).call(req).await
        } else if E::get(&format!("{}/index.html", path)).is_some() {
            Ok(Response::builder()
                .status(StatusCode::FOUND)
                .header(LOCATION, format!("{}/", original_path))
                .finish())
        } else {
            log::info!("path: {path} not found, fallback to index.html");
            EmbeddedFileEndpoint::<E>::new(&format!("index.html")).call(req).await
        }
    }
}