server_server.rs

use crate::{client_server, utils, ConduitResult, Database, Error, PduEvent, Result, Ruma};
use get_devices::v1::UserDevice;
use get_profile_information::v1::ProfileField;
use http::header::{HeaderValue, AUTHORIZATION, HOST};
use log::{error, info, warn};
use rocket::{get, post, put, response::content::Json, State};
use ruma::{
    api::{
        federation::{
            device::get_devices,
            directory::{get_public_rooms, get_public_rooms_filtered},
            discovery::{
                get_server_keys, get_server_version::v1 as get_server_version, ServerSigningKeys,
                VerifyKey,
            },
            event::{get_event, get_missing_events, get_room_state_ids},
            query::get_profile_information,
            transactions::send_transaction_message,
        },
        OutgoingRequest,
    },
    directory::{IncomingFilter, IncomingRoomNetwork},
    serde::to_canonical_value,
    signatures::{CanonicalJsonObject, CanonicalJsonValue, PublicKeyMap},
    EventId, RoomId, RoomVersionId, ServerName, ServerSigningKeyId, UserId,
};
use state_res::{Event, StateMap};
use std::{
    collections::{BTreeMap, BTreeSet},
    convert::{TryFrom, TryInto},
    fmt::Debug,
    net::{IpAddr, SocketAddr},
    sync::Arc,
    time::{Duration, SystemTime},
};

pub async fn send_request<T: OutgoingRequest>(
    globals: &crate::database::globals::Globals,
    destination: Box<ServerName>,
    request: T,
) -> Result<T::IncomingResponse>
where
    T: Debug,
{
    if !globals.allow_federation() {
        return Err(Error::bad_config("Federation is disabled."));
    }

    let maybe_result = globals
        .actual_destination_cache
        .read()
        .unwrap()
        .get(&destination)
        .cloned();

    let (actual_destination, host) = if let Some(result) = maybe_result {
        result
    } else {
        let result = find_actual_destination(globals, &destination).await;
        globals
            .actual_destination_cache
            .write()
            .unwrap()
            .insert(destination.clone(), result.clone());
        result
    };

    let mut http_request = request
        .try_into_http_request(&actual_destination, Some(""))
        .map_err(|e| {
            warn!("Failed to find destination {}: {}", actual_destination, e);
            Error::BadServerResponse("Invalid destination")
        })?;

    let mut request_map = serde_json::Map::new();

    if !http_request.body().is_empty() {
        request_map.insert(
            "content".to_owned(),
            serde_json::from_slice(http_request.body())
                .expect("body is valid json, we just created it"),
        );
    };

    request_map.insert("method".to_owned(), T::METADATA.method.to_string().into());
    request_map.insert(
        "uri".to_owned(),
        http_request
            .uri()
            .path_and_query()
            .expect("all requests have a path")
            .to_string()
            .into(),
    );
    request_map.insert("origin".to_owned(), globals.server_name().as_str().into());
    request_map.insert("destination".to_owned(), destination.as_str().into());

    let mut request_json =
        serde_json::from_value(request_map.into()).expect("valid JSON is valid BTreeMap");

    ruma::signatures::sign_json(
        globals.server_name().as_str(),
        globals.keypair(),
        &mut request_json,
    )
    .expect("our request json is what ruma expects");

    let request_json: serde_json::Map<String, serde_json::Value> =
        serde_json::from_slice(&serde_json::to_vec(&request_json).unwrap()).unwrap();

    let signatures = request_json["signatures"]
        .as_object()
        .unwrap()
        .values()
        .map(|v| {
            v.as_object()
                .unwrap()
                .iter()
                .map(|(k, v)| (k, v.as_str().unwrap()))
        });

    for signature_server in signatures {
        for s in signature_server {
            http_request.headers_mut().insert(
                AUTHORIZATION,
                HeaderValue::from_str(&format!(
                    "X-Matrix origin={},key=\"{}\",sig=\"{}\"",
                    globals.server_name(),
                    s.0,
                    s.1
                ))
                .unwrap(),
            );
        }
    }

    if let Some(host) = host {
        http_request
            .headers_mut()
            .insert(HOST, HeaderValue::from_str(&host).unwrap());
    }

    let mut reqwest_request = reqwest::Request::try_from(http_request)
        .expect("all http requests are valid reqwest requests");

    *reqwest_request.timeout_mut() = Some(Duration::from_secs(30));

    let url = reqwest_request.url().clone();
    let reqwest_response = globals.reqwest_client().execute(reqwest_request).await;

    // Because reqwest::Response -> http::Response is complicated:
    match reqwest_response {
        Ok(mut reqwest_response) => {
            let status = reqwest_response.status();
            let mut http_response = http::Response::builder().status(status);
            let headers = http_response.headers_mut().unwrap();

            for (k, v) in reqwest_response.headers_mut().drain() {
                if let Some(key) = k {
                    headers.insert(key, v);
                }
            }

            let status = reqwest_response.status();

            let body = reqwest_response
                .bytes()
                .await
                .unwrap_or_else(|e| {
                    warn!("server error {}", e);
                    Vec::new().into()
                }) // TODO: handle timeout
                .into_iter()
                .collect::<Vec<_>>();

            if status != 200 {
                info!(
                    "Server returned bad response {} {}\n{}\n{:?}",
                    destination,
                    status,
                    url,
                    utils::string_from_bytes(&body)
                );
            }

            let response = T::IncomingResponse::try_from(
                http_response
                    .body(body)
                    .expect("reqwest body is valid http body"),
            );
            response.map_err(|_| {
                info!(
                    "Server returned invalid response bytes {}\n{}",
                    destination, url
                );
                Error::BadServerResponse("Server returned bad response.")
            })
        }
        Err(e) => Err(e.into()),
    }
}

fn get_ip_with_port(destination_str: String) -> Option<String> {
    if destination_str.parse::<SocketAddr>().is_ok() {
        Some(destination_str)
    } else if let Ok(ip_addr) = destination_str.parse::<IpAddr>() {
        Some(SocketAddr::new(ip_addr, 8448).to_string())
    } else {
        None
    }
}

fn add_port_to_hostname(destination_str: String) -> String {
    match destination_str.find(':') {
        None => destination_str.to_owned() + ":8448",
        Some(_) => destination_str.to_string(),
    }
}

/// Returns: actual_destination, host header
/// Implemented according to the specification at https://matrix.org/docs/spec/server_server/r0.1.4#resolving-server-names
/// Numbers in comments below refer to bullet points in linked section of specification
async fn find_actual_destination(
    globals: &crate::database::globals::Globals,
    destination: &ServerName,
) -> (String, Option<String>) {
    let mut host = None;

    let destination_str = destination.as_str().to_owned();
    let actual_destination = "https://".to_owned()
        + &match get_ip_with_port(destination_str.clone()) {
            Some(host_port) => {
                // 1: IP literal with provided or default port
                host_port
            }
            None => {
                if destination_str.find(':').is_some() {
                    // 2: Hostname with included port
                    destination_str
                } else {
                    match request_well_known(globals, &destination.as_str()).await {
                        // 3: A .well-known file is available
                        Some(delegated_hostname) => {
                            match get_ip_with_port(delegated_hostname.clone()) {
                                Some(host_and_port) => host_and_port, // 3.1: IP literal in .well-known file
                                None => {
                                    if destination_str.find(':').is_some() {
                                        // 3.2: Hostname with port in .well-known file
                                        destination_str
                                    } else {
                                        match query_srv_record(globals, &delegated_hostname).await {
                                            // 3.3: SRV lookup successful
                                            Some(hostname) => hostname,
                                            // 3.4: No SRV records, just use the hostname from .well-known
                                            None => add_port_to_hostname(delegated_hostname),
                                        }
                                    }
                                }
                            }
                        }
                        // 4: No .well-known or an error occured
                        None => {
                            match query_srv_record(globals, &destination_str).await {
                                // 4: SRV record found
                                Some(hostname) => {
                                    host = Some(destination_str.to_owned());
                                    hostname
                                }
                                // 5: No SRV record found
                                None => add_port_to_hostname(destination_str.to_string()),
                            }
                        }
                    }
                }
            }
        };

    (actual_destination, host)
}

async fn query_srv_record<'a>(
    globals: &crate::database::globals::Globals,
    hostname: &'a str,
) -> Option<String> {
    if let Ok(Some(host_port)) = globals
        .dns_resolver()
        .srv_lookup(format!("_matrix._tcp.{}", hostname))
        .await
        .map(|srv| {
            srv.iter().next().map(|result| {
                format!(
                    "{}:{}",
                    result.target().to_string().trim_end_matches('.'),
                    result.port().to_string()
                )
            })
        })
    {
        Some(host_port)
    } else {
        None
    }
}

pub async fn request_well_known(
    globals: &crate::database::globals::Globals,
    destination: &str,
) -> Option<String> {
    let body: serde_json::Value = serde_json::from_str(
        &globals
            .reqwest_client()
            .get(&format!(
                "https://{}/.well-known/matrix/server",
                destination
            ))
            .send()
            .await
            .ok()?
            .text()
            .await
            .ok()?,
    )
    .ok()?;
    Some(body.get("m.server")?.as_str()?.to_owned())
}

#[cfg_attr(feature = "conduit_bin", get("/_matrix/federation/v1/version"))]
pub fn get_server_version_route(
    db: State<'_, Database>,
) -> ConduitResult<get_server_version::Response> {
    if !db.globals.allow_federation() {
        return Err(Error::bad_config("Federation is disabled."));
    }

    Ok(get_server_version::Response {
        server: Some(get_server_version::Server {
            name: Some("Conduit".to_owned()),
            version: Some(env!("CARGO_PKG_VERSION").to_owned()),
        }),
    }
    .into())
}

#[cfg_attr(feature = "conduit_bin", get("/_matrix/key/v2/server"))]
pub fn get_server_keys_route(db: State<'_, Database>) -> Json<String> {
    if !db.globals.allow_federation() {
        // TODO: Use proper types
        return Json("Federation is disabled.".to_owned());
    }

    let mut verify_keys = BTreeMap::new();
    verify_keys.insert(
        ServerSigningKeyId::try_from(
            format!("ed25519:{}", db.globals.keypair().version()).as_str(),
        )
        .expect("found invalid server signing keys in DB"),
        VerifyKey {
            key: base64::encode_config(db.globals.keypair().public_key(), base64::STANDARD_NO_PAD),
        },
    );
    let mut response = serde_json::from_slice(
        http::Response::try_from(get_server_keys::v2::Response {
            server_key: ServerSigningKeys {
                server_name: db.globals.server_name().to_owned(),
                verify_keys,
                old_verify_keys: BTreeMap::new(),
                signatures: BTreeMap::new(),
                valid_until_ts: SystemTime::now() + Duration::from_secs(60 * 2),
            },
        })
        .unwrap()
        .body(),
    )
    .unwrap();

    ruma::signatures::sign_json(
        db.globals.server_name().as_str(),
        db.globals.keypair(),
        &mut response,
    )
    .unwrap();

    Json(ruma::serde::to_canonical_json_string(&response).expect("JSON is canonical"))
}

#[cfg_attr(feature = "conduit_bin", get("/_matrix/key/v2/server/<_>"))]
pub fn get_server_keys_deprecated_route(db: State<'_, Database>) -> Json<String> {
    get_server_keys_route(db)
}

#[cfg_attr(
    feature = "conduit_bin",
    post("/_matrix/federation/v1/publicRooms", data = "<body>")
)]
pub async fn get_public_rooms_filtered_route(
    db: State<'_, Database>,
    body: Ruma<get_public_rooms_filtered::v1::Request<'_>>,
) -> ConduitResult<get_public_rooms_filtered::v1::Response> {
    if !db.globals.allow_federation() {
        return Err(Error::bad_config("Federation is disabled."));
    }

    let response = client_server::get_public_rooms_filtered_helper(
        &db,
        None,
        body.limit,
        body.since.as_deref(),
        &body.filter,
        &body.room_network,
    )
    .await?
    .0;

    Ok(get_public_rooms_filtered::v1::Response {
        chunk: response
            .chunk
            .into_iter()
            .map(|c| {
                // Convert ruma::api::federation::directory::get_public_rooms::v1::PublicRoomsChunk
                // to ruma::api::client::r0::directory::PublicRoomsChunk
                Ok::<_, Error>(
                    serde_json::from_str(
                        &serde_json::to_string(&c)
                            .expect("PublicRoomsChunk::to_string always works"),
                    )
                    .expect("federation and client-server PublicRoomsChunk are the same type"),
                )
            })
            .filter_map(|r| r.ok())
            .collect(),
        prev_batch: response.prev_batch,
        next_batch: response.next_batch,
        total_room_count_estimate: response.total_room_count_estimate,
    }
    .into())
}

#[cfg_attr(
    feature = "conduit_bin",
    get("/_matrix/federation/v1/publicRooms", data = "<body>")
)]
pub async fn get_public_rooms_route(
    db: State<'_, Database>,
    body: Ruma<get_public_rooms::v1::Request<'_>>,
) -> ConduitResult<get_public_rooms::v1::Response> {
    if !db.globals.allow_federation() {
        return Err(Error::bad_config("Federation is disabled."));
    }

    let response = client_server::get_public_rooms_filtered_helper(
        &db,
        None,
        body.limit,
        body.since.as_deref(),
        &IncomingFilter::default(),
        &IncomingRoomNetwork::Matrix,
    )
    .await?
    .0;

    Ok(get_public_rooms::v1::Response {
        chunk: response
            .chunk
            .into_iter()
            .map(|c| {
                // Convert ruma::api::federation::directory::get_public_rooms::v1::PublicRoomsChunk
                // to ruma::api::client::r0::directory::PublicRoomsChunk
                Ok::<_, Error>(
                    serde_json::from_str(
                        &serde_json::to_string(&c)
                            .expect("PublicRoomsChunk::to_string always works"),
                    )
                    .expect("federation and client-server PublicRoomsChunk are the same type"),
                )
            })
            .filter_map(|r| r.ok())
            .collect(),
        prev_batch: response.prev_batch,
        next_batch: response.next_batch,
        total_room_count_estimate: response.total_room_count_estimate,
    }
    .into())
}

#[derive(Clone, Debug, Ord, PartialOrd, Eq, PartialEq)]
pub enum PrevEvents<T> {
    Sequential(T),
    Fork(Vec<T>),
}

impl<T> IntoIterator for PrevEvents<T> {
    type Item = T;
    type IntoIter = std::vec::IntoIter<Self::Item>;

    fn into_iter(self) -> Self::IntoIter {
        match self {
            Self::Sequential(item) => vec![item].into_iter(),
            Self::Fork(list) => list.into_iter(),
        }
    }
}

impl<T: Clone> PrevEvents<T> {
    pub fn new(id: &[T]) -> Self {
        match id {
            [] => panic!("All events must have previous event"),
            [single_id] => Self::Sequential(single_id.clone()),
            rest => Self::Fork(rest.to_vec()),
        }
    }
}

#[cfg_attr(
    feature = "conduit_bin",
    put("/_matrix/federation/v1/send/<_>", data = "<body>")
)]
pub async fn send_transaction_message_route<'a>(
    db: State<'a, Database>,
    body: Ruma<send_transaction_message::v1::Request<'_>>,
) -> ConduitResult<send_transaction_message::v1::Response> {
    if !db.globals.allow_federation() {
        return Err(Error::bad_config("Federation is disabled."));
    }

    dbg!(&*body);

    for edu in &body.edus {
        match serde_json::from_str::<send_transaction_message::v1::Edu>(edu.json().get()) {
            Ok(edu) => match edu.edu_type.as_str() {
                "m.typing" => {
                    if let Some(typing) = edu.content.get("typing") {
                        if typing.as_bool().unwrap_or_default() {
                            db.rooms.edus.typing_add(
                                &UserId::try_from(edu.content["user_id"].as_str().unwrap())
                                    .unwrap(),
                                &RoomId::try_from(edu.content["room_id"].as_str().unwrap())
                                    .unwrap(),
                                3000 + utils::millis_since_unix_epoch(),
                                &db.globals,
                            )?;
                        } else {
                            db.rooms.edus.typing_remove(
                                &UserId::try_from(edu.content["user_id"].as_str().unwrap())
                                    .unwrap(),
                                &RoomId::try_from(edu.content["room_id"].as_str().unwrap())
                                    .unwrap(),
                                &db.globals,
                            )?;
                        }
                    }
                }
                "m.presence" => {}
                "m.receipt" => {}
                "m.device_list_update" => {}
                _ => {}
            },
            Err(_err) => {
                continue;
            }
        }
    }

    // TODO: For RoomVersion6 we must check that Raw<..> is canonical do we anywhere?
    // SPEC:
    // Servers MUST strictly enforce the JSON format specified in the appendices.
    // This translates to a 400 M_BAD_JSON error on most endpoints, or discarding of
    // events over federation. For example, the Federation API's /send endpoint would
    // discard the event whereas the Client Server API's /send/{eventType} endpoint
    // would return a M_BAD_JSON error.
    let mut resolved_map = BTreeMap::new();
    for pdu in &body.pdus {
        // 1. Is a valid event, otherwise it is dropped.
        // Ruma/PduEvent/StateEvent satisfies this
        // We do not add the event_id field to the pdu here because of signature and hashes checks
        // TODO: ruma may solve this but our `process_incoming_pdu` needs to return a Result then
        let (event_id, value) = crate::pdu::process_incoming_pdu(pdu);
        // 2. Passes signature checks, otherwise event is dropped.
        // 3. Passes hash checks, otherwise it is redacted before being processed further.
        let server_name = body.body.origin.clone();
        let mut pub_key_map = BTreeMap::new();
        if let Some(sig) = value.get("signatures") {
            match sig {
                CanonicalJsonValue::Object(entity) => {
                    for key in entity.keys() {
                        // TODO: save this in a DB maybe...
                        // fetch the public signing key
                        let res = db
                            .sending
                            .send_federation_request(
                                &db.globals,
                                Box::<ServerName>::try_from(key.to_string()).unwrap(),
                                get_server_keys::v2::Request::new(),
                            )
                            .await?;

                        pub_key_map.insert(
                            res.server_key.server_name.to_string(),
                            res.server_key
                                .verify_keys
                                .into_iter()
                                .map(|(k, v)| (k.to_string(), v.key))
                                .collect(),
                        );
                    }
                }
                _ => {
                    resolved_map.insert(
                        event_id,
                        Err("`signatures` is not a JSON object".to_string()),
                    );
                    continue;
                }
            }
        } else {
            resolved_map.insert(event_id, Err("No field `signatures` in JSON".to_string()));
            continue;
        }

        let mut val = match signature_and_hash_check(&pub_key_map, value) {
            Ok(pdu) => pdu,
            Err(e) => {
                resolved_map.insert(event_id, Err(e));
                continue;
            }
        };

        // Now that we have checked the signature and hashes we can add the eventID and convert
        // to our PduEvent type
        val.insert(
            "event_id".to_owned(),
            to_canonical_value(&event_id).expect("EventId is a valid CanonicalJsonValue"),
        );
        let pdu = serde_json::from_value::<PduEvent>(
            serde_json::to_value(val).expect("CanonicalJsonObj is a valid JsonValue"),
        )
        .expect("Pdu is valid Canonical JSON Map");

        // If we have no idea about this room skip the PDU
        if !db.rooms.exists(&pdu.room_id)? {
            resolved_map.insert(event_id, Err("Room is unknown to this server".into()));
            continue;
        }

        let event = Arc::new(pdu.clone());
        dbg!(&*event);
        // Fetch any unknown prev_events or retrieve them from the DB
        let previous =
            match fetch_events(&db, server_name.clone(), &pub_key_map, &pdu.prev_events).await {
                Ok(mut evs) if evs.len() == 1 => Some(Arc::new(evs.remove(0))),
                _ => None,
            };

        // 4. Passes authorization rules based on the event's auth events, otherwise it is rejected.
        // Recursively gather all auth events checking that the previous auth events are valid.
        let auth_events: Vec<PduEvent> =
            match fetch_check_auth_events(&db, server_name.clone(), &pub_key_map, &pdu.prev_events)
                .await
            {
                Ok(events) => events,
                Err(_) => {
                    resolved_map.insert(
                        pdu.event_id,
                        Err("Failed to recursively gather auth events".into()),
                    );
                    continue;
                }
            };

        let mut event_map: state_res::EventMap<Arc<PduEvent>> = auth_events
            .iter()
            .map(|v| (v.event_id().clone(), Arc::new(v.clone())))
            .collect();

        // Check that the event passes auth based on the auth_events
        let is_authed = state_res::event_auth::auth_check(
            &RoomVersionId::Version6,
            &event,
            previous.clone(),
            &pdu.auth_events
                .iter()
                .map(|id| {
                    event_map
                        .get(id)
                        .map(|pdu| ((pdu.kind(), pdu.state_key()), pdu.clone()))
                        .ok_or_else(|| {
                            Error::Conflict(
                                "Auth event not found, event failed recursive auth checks.",
                            )
                        })
                })
                .collect::<Result<BTreeMap<_, _>>>()?,
            None, // TODO: third party invite
        )
        .map_err(|_e| Error::Conflict("Auth check failed"))?;
        if !is_authed {
            resolved_map.insert(
                pdu.event_id,
                Err("Event has failed auth check with auth events".into()),
            );
            continue;
        }
        // End of step 4.

        // Step 5. event passes auth based on state at the event
        let (state_at_event, incoming_auth_events): (StateMap<Arc<PduEvent>>, Vec<Arc<PduEvent>>) =
            match db
                .sending
                .send_federation_request(
                    &db.globals,
                    server_name.clone(),
                    get_room_state_ids::v1::Request {
                        room_id: pdu.room_id(),
                        event_id: pdu.event_id(),
                    },
                )
                .await
            {
                Ok(res) => {
                    let state =
                        fetch_events(&db, server_name.clone(), &pub_key_map, &res.pdu_ids).await?;
                    // Sanity check: there are no conflicting events in the state we received
                    let mut seen = BTreeSet::new();
                    for ev in &state {
                        // If the key is already present
                        if !seen.insert((&ev.kind, &ev.state_key)) {
                            todo!("Server sent us an invalid state")
                        }
                    }

                    let state = state
                        .into_iter()
                        .map(|pdu| ((pdu.kind.clone(), pdu.state_key.clone()), Arc::new(pdu)))
                        .collect();

                    (
                        state,
                        fetch_events(&db, server_name.clone(), &pub_key_map, &res.auth_chain_ids)
                            .await?
                            .into_iter()
                            .map(Arc::new)
                            .collect(),
                    )
                }
                Err(_) => {
                    resolved_map.insert(
                        event.event_id().clone(),
                        Err("Fetching state for event failed".into()),
                    );
                    continue;
                }
            };

        if !state_res::event_auth::auth_check(
            &RoomVersionId::Version6,
            &event,
            previous.clone(),
            &state_at_event,
            None, // TODO: third party invite
        )
        .map_err(|_e| Error::Conflict("Auth check failed"))?
        {
            // Event failed auth with state_at
            resolved_map.insert(
                pdu.event_id,
                Err("Event has failed auth check with state at the event".into()),
            );
            continue;
        }
        // End of step 5.

        // The event could still be soft failed
        append_state_soft(&db, &pdu)?;

        // Gather the forward extremities and resolve
        let forward_extrems = forward_extremity_ids(&db, &pdu.room_id)?;
        let mut fork_states: Vec<StateMap<Arc<PduEvent>>> = vec![];
        for id in &forward_extrems {
            if let Some(id) = db.rooms.get_pdu_id(id)? {
                let state_hash = db
                    .rooms
                    .pdu_state_hash(&id)?
                    .expect("found pdu with no statehash");
                let state = db
                    .rooms
                    .state_full(&pdu.room_id, &state_hash)?
                    .into_iter()
                    .map(|(k, v)| ((k.0, Some(k.1)), Arc::new(v)))
                    .collect();

                fork_states.push(state);
            } else {
                todo!("we don't know of a pdu that is part of our known forks OOPS")
            }
        }

        // Step 6. event passes auth based on state of all forks and current room state
        let state_at_forks = if fork_states.is_empty() {
            // State is empty
            Default::default()
        } else if fork_states.len() == 1 {
            fork_states[0].clone()
        } else {
            let auth_events = fork_states
                .iter()
                .map(|map| {
                    db.rooms
                        .auth_events_full(
                            pdu.room_id(),
                            &map.values()
                                .map(|pdu| pdu.event_id().clone())
                                .collect::<Vec<_>>(),
                        )
                        .map(|pdus| pdus.into_iter().map(Arc::new).collect::<Vec<_>>())
                })
                .collect::<Result<Vec<_>>>()?;

            // Add everything we will need to event_map
            event_map.extend(
                auth_events
                    .iter()
                    .map(|pdus| pdus.iter().map(|pdu| (pdu.event_id().clone(), pdu.clone())))
                    .flatten(),
            );
            event_map.extend(
                incoming_auth_events
                    .into_iter()
                    .map(|pdu| (pdu.event_id().clone(), pdu)),
            );
            event_map.extend(
                state_at_event
                    .into_iter()
                    .map(|(_, pdu)| (pdu.event_id().clone(), pdu)),
            );

            match state_res::StateResolution::resolve(
                &pdu.room_id,
                &RoomVersionId::Version6,
                &fork_states
                    .into_iter()
                    .map(|map| {
                        map.into_iter()
                            .map(|(k, v)| (k, v.event_id.clone()))
                            .collect::<StateMap<_>>()
                    })
                    .collect::<Vec<_>>(),
                auth_events
                    .into_iter()
                    .map(|pdus| pdus.into_iter().map(|pdu| pdu.event_id().clone()).collect())
                    .collect(),
                &mut event_map,
            ) {
                Ok(res) => res
                    .into_iter()
                    .map(|(k, v)| (k, Arc::new(db.rooms.get_pdu(&v).unwrap().unwrap())))
                    .collect(),
                Err(e) => panic!("{:?}", e),
            }
        };

        if !state_res::event_auth::auth_check(
            &RoomVersionId::Version6,
            &event,
            previous,
            &state_at_forks,
            None,
        )
        .map_err(|_e| Error::Conflict("Auth check failed"))?
        {
            // Soft fail
            resolved_map.insert(
                event.event_id().clone(),
                Err("Event has been soft failed".into()),
            );
        } else {
            append_state(&db, &pdu)?;
            // Event has passed all auth/stateres checks
            resolved_map.insert(event.event_id().clone(), Ok(()));
        }
    }

    Ok(dbg!(send_transaction_message::v1::Response { pdus: resolved_map }).into())
}

fn signature_and_hash_check(
    pub_key_map: &ruma::signatures::PublicKeyMap,
    value: CanonicalJsonObject,
) -> std::result::Result<CanonicalJsonObject, String> {
    Ok(
        match ruma::signatures::verify_event(pub_key_map, &value, &RoomVersionId::Version6) {
            Ok(ver) => {
                if let ruma::signatures::Verified::Signatures = ver {
                    error!("CONTENT HASH FAILED");
                    match ruma::signatures::redact(&value, &RoomVersionId::Version6) {
                        Ok(obj) => obj,
                        Err(_) => return Err("Redaction failed".to_string()),
                    }
                } else {
                    value
                }
            }
            Err(_e) => {
                return Err("Signature verification failed".to_string());
            }
        },
    )
}

/// The check in `fetch_check_auth_events` is that a complete chain is found for the
/// events `auth_events`. If the chain is found to have missing events it fails.
async fn fetch_check_auth_events(
    db: &Database,
    origin: Box<ServerName>,
    key_map: &PublicKeyMap,
    event_ids: &[EventId],
) -> Result<Vec<PduEvent>> {
    let mut result = BTreeMap::new();
    let mut stack = event_ids.to_vec();

    // DFS for auth event chain
    while !stack.is_empty() {
        let ev_id = stack.pop().unwrap();
        if result.contains_key(&ev_id) {
            continue;
        }

        let ev = match db.rooms.get_pdu(&ev_id)? {
            Some(pdu) => pdu,
            None => match db
                .sending
                .send_federation_request(
                    &db.globals,
                    origin.clone(),
                    get_event::v1::Request { event_id: &ev_id },
                )
                .await
            {
                Ok(res) => {
                    let (event_id, value) = crate::pdu::process_incoming_pdu(&res.pdu);
                    match signature_and_hash_check(key_map, value) {
                        Ok(mut val) => {
                            val.insert(
                                "event_id".to_owned(),
                                to_canonical_value(&event_id)
                                    .expect("EventId is a valid CanonicalJsonValue"),
                            );
                            serde_json::from_value::<PduEvent>(
                                serde_json::to_value(val)
                                    .expect("CanonicalJsonObj is a valid JsonValue"),
                            )
                            .expect("Pdu is valid Canonical JSON Map")
                        }
                        Err(e) => {
                            // TODO: I would assume we just keep going
                            error!("{:?}", e);
                            continue;
                        }
                    }
                }
                Err(_) => return Err(Error::BadServerResponse("Failed to fetch event")),
            },
        };
        stack.extend(ev.auth_events());
        result.insert(ev.event_id().clone(), ev);
    }

    Ok(result.into_iter().map(|(_, v)| v).collect())
}

/// TODO: this needs to add events to the DB in a way that does not
/// effect the state of the room
async fn fetch_events(
    db: &Database,
    origin: Box<ServerName>,
    key_map: &PublicKeyMap,
    events: &[EventId],
) -> Result<Vec<PduEvent>> {
    let mut pdus = vec![];
    for id in events {
        match db.rooms.get_pdu(id)? {
            Some(pdu) => pdus.push(pdu),
            None => match db
                .sending
                .send_federation_request(
                    &db.globals,
                    origin.clone(),
                    get_event::v1::Request { event_id: id },
                )
                .await
            {
                Ok(res) => {
                    let (event_id, value) = crate::pdu::process_incoming_pdu(&res.pdu);
                    match signature_and_hash_check(key_map, value) {
                        Ok(mut val) => {
                            // TODO: add to our DB somehow?
                            val.insert(
                                "event_id".to_owned(),
                                to_canonical_value(&event_id)
                                    .expect("EventId is a valid CanonicalJsonValue"),
                            );
                            let pdu = serde_json::from_value::<PduEvent>(