use actix_web::{http::StatusCode, web, App, HttpRequest, HttpResponse, HttpServer, ResponseError};
use base64::{engine::general_purpose::STANDARD, Engine};
use http_signature_normalization_actix::{digest::ring::Sha256, prelude::*};
use std::future::{ready, Ready};
use tracing::info;
use tracing_actix_web::TracingLogger;
use tracing_error::ErrorLayer;
use tracing_subscriber::{layer::SubscriberExt, EnvFilter};

#[derive(Clone, Debug)]
struct MyVerify;

impl SignatureVerify for MyVerify {
    type Error = MyError;
    type Future = Ready<Result<bool, Self::Error>>;

    fn signature_verify(
        &mut self,
        algorithm: Option<Algorithm>,
        key_id: String,
        signature: String,
        signing_string: String,
    ) -> Self::Future {
        match algorithm {
            Some(Algorithm::Hs2019) => (),
            _ => return ready(Err(MyError::Algorithm)),
        };

        if key_id != "my-key-id" {
            return ready(Err(MyError::Key));
        }

        let decoded = match STANDARD.decode(&signature) {
            Ok(decoded) => decoded,
            Err(_) => return ready(Err(MyError::Decode)),
        };

        info!("Signing String\n{}", signing_string);

        ready(Ok(decoded == signing_string.as_bytes()))
    }
}

async fn index(
    _: DigestVerified,
    sig_verified: SignatureVerified,
    req: HttpRequest,
    _body: web::Bytes,
) -> &'static str {
    info!("Verified request for {}", sig_verified.key_id());
    info!("{:?}", req);
    "Eyyyyup"
}

#[actix_rt::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let env_filter = EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("info"));

    let subscriber = tracing_subscriber::Registry::default()
        .with(env_filter)
        .with(ErrorLayer::default())
        .with(tracing_subscriber::fmt::layer());

    tracing::subscriber::set_global_default(subscriber)?;

    let config = Config::new().require_header("accept").require_digest();

    HttpServer::new(move || {
        App::new()
            .wrap(VerifyDigest::new(Sha256::new()).optional())
            .wrap(VerifySignature::new(MyVerify, config.clone()))
            .wrap(TracingLogger::default())
            .route("/", web::post().to(index))
    })
    .bind("127.0.0.1:8010")?
    .run()
    .await?;

    Ok(())
}

#[derive(Debug, thiserror::Error)]
enum MyError {
    #[error("Failed to verify, {0}")]
    Verify(#[from] PrepareVerifyError),

    #[error("Unsupported algorithm")]
    Algorithm,

    #[error("Couldn't decode signature")]
    Decode,

    #[error("Invalid key")]
    Key,
}

impl ResponseError for MyError {
    fn status_code(&self) -> StatusCode {
        StatusCode::BAD_REQUEST
    }

    fn error_response(&self) -> HttpResponse {
        HttpResponse::BadRequest().finish()
    }
}