use std::{net::SocketAddr, sync::Arc};

use disasmer_core::{
    ArtifactId, DataPlaneObject, DataPlaneScope, Digest, NativeQuicTransport, NodeEndpoint, NodeId,
    ProcessId, ProjectId, RendezvousRequest, TenantId, Transport,
};
use quinn::rustls::{
    pki_types::{CertificateDer, PrivateKeyDer, PrivatePkcs8KeyDer},
    RootCertStore,
};
use quinn::{ClientConfig, Endpoint, ServerConfig};
use serde::{Deserialize, Serialize};
use serde_json::json;

#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
struct QuicTransferRequest {
    scope: DataPlaneScope,
    authorization_digest: Digest,
    requested_bytes: u64,
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
    let payload = b"artifact-bytes-over-rust-native-quic".to_vec();
    let (cert, key) = self_signed_localhost_cert()?;
    let server_endpoint = Endpoint::server(
        ServerConfig::with_single_cert(vec![cert.clone()], key)?,
        "127.0.0.1:0".parse()?,
    )?;
    let server_addr = server_endpoint.local_addr()?;

    let scope = DataPlaneScope {
        tenant: TenantId::from("tenant"),
        project: ProjectId::from("project"),
        process: ProcessId::from("vp-quic"),
        object: DataPlaneObject::Artifact(ArtifactId::from("quic-artifact")),
        authorization_subject: "node-a-to-node-b".to_owned(),
    };
    let transport = NativeQuicTransport;
    let plan = transport.plan_authenticated_direct_bulk_transfer(
        RendezvousRequest {
            scope: scope.clone(),
            source: endpoint("node-a", server_addr),
            destination: endpoint("node-b", "127.0.0.1:0".parse()?),
        },
        true,
        "",
    )?;

    let expected_scope = plan.scope.clone();
    let expected_digest = plan.authorization_digest.clone();
    let expected_payload = payload.clone();
    let server = tokio::spawn(async move {
        let incoming = server_endpoint
            .accept()
            .await
            .ok_or("server endpoint closed before accepting a QUIC connection")?;
        let connection = incoming.await?;
        let (mut send, mut recv) = connection.accept_bi().await?;
        let request_bytes = recv.read_to_end(64 * 1024).await?;
        let request: QuicTransferRequest = serde_json::from_slice(&request_bytes)?;
        if request.scope != expected_scope {
            return Err("QUIC request scope did not match the authorized data-plane scope".into());
        }
        if request.authorization_digest != expected_digest {
            return Err(
                "QUIC request authorization digest did not match the rendezvous plan".into(),
            );
        }
        send.write_all(&expected_payload).await?;
        send.finish()?;
        server_endpoint.wait_idle().await;
        Ok::<usize, Box<dyn std::error::Error + Send + Sync>>(request_bytes.len())
    });

    let mut roots = RootCertStore::empty();
    roots.add(cert)?;
    let client_config = ClientConfig::with_root_certificates(Arc::new(roots))?;
    let mut client_endpoint = Endpoint::client("127.0.0.1:0".parse()?)?;
    client_endpoint.set_default_client_config(client_config);

    let connection = client_endpoint.connect(server_addr, "localhost")?.await?;
    let (mut send, mut recv) = connection.open_bi().await?;
    let request = QuicTransferRequest {
        scope: plan.scope.clone(),
        authorization_digest: plan.authorization_digest.clone(),
        requested_bytes: payload.len() as u64,
    };
    let request_bytes = serde_json::to_vec(&request)?;
    send.write_all(&request_bytes).await?;
    send.finish()?;
    let received = recv.read_to_end(64 * 1024).await?;
    connection.close(0u32.into(), b"done");
    client_endpoint.wait_idle().await;
    let server_received_request_bytes = server.await??;

    if received != payload {
        return Err("QUIC artifact payload did not round trip".into());
    }

    println!(
        "{}",
        json!({
            "kind": "disasmer_quic_smoke",
            "transport": format!("{:?}", transport.kind()),
            "rust_native_quic": true,
            "authenticated_direct_connection": transport.authenticated_direct_connections(),
            "coordinator_assisted_rendezvous": plan.coordinator_assisted_rendezvous,
            "coordinator_bulk_relay_allowed": plan.coordinator_bulk_relay_allowed,
            "source_node": plan.source.node,
            "destination_node": plan.destination.node,
            "scope": plan.scope,
            "request_bytes": request_bytes.len(),
            "server_received_request_bytes": server_received_request_bytes,
            "payload_bytes": received.len(),
            "authorization_digest": plan.authorization_digest,
        })
    );

    Ok(())
}

fn self_signed_localhost_cert() -> Result<
    (CertificateDer<'static>, PrivateKeyDer<'static>),
    Box<dyn std::error::Error + Send + Sync>,
> {
    let cert = rcgen::generate_simple_self_signed(vec!["localhost".to_owned()])?;
    let key = PrivateKeyDer::Pkcs8(PrivatePkcs8KeyDer::from(cert.signing_key.serialize_der()));
    Ok((cert.cert.into(), key))
}

fn endpoint(name: &str, addr: SocketAddr) -> NodeEndpoint {
    NodeEndpoint {
        node: NodeId::from(name),
        advertised_addr: addr.to_string(),
        public_key_fingerprint: Digest::sha256(format!("{name}-public-key")),
    }
}