pub mod service;

use geth_auth::AuthExplanation;
use geth_cas::{LocalCas, hash_path};
use geth_config::{GethConfig, GethPaths, RelayMode};
use geth_control::{
    CasBlob, ControlRequest, ControlResponse, KeychainStatusResponse, NodeIdResponse,
    StatusResponse,
};
use geth_crypto::AgentKey;
use geth_iroh::{EndpointStatus, GethIrohConfig, GethIrohEndpoint, GethRelayMode};
use geth_resource::ResourceDescriptor;
use geth_ssh_identity::{
    SshCertApproval, SshCertKind, SshCertRequest, SshCertRequestStatus, SshCertificateRecord,
    SshRevocationEntry, SshRevocationKind, build_ssh_cert_sign_command, cert_request_id,
    certificate_id, revocation_id, ssh_public_key_fingerprint,
};
use geth_store::{
    Store, StoredResource, StoredSshCertRequest, StoredSshCertificate, StoredSshRevocation,
};
use geth_types::{
    NodeId, ResourceId, ResourceKind, ResourceName, SshCertId, SshCertRequestId, UnixMillis,
};
use std::path::Path;
use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
use tokio::net::{UnixListener, UnixStream};

#[derive(Debug, thiserror::Error)]
pub enum NodeError {
    #[error("config error: {0}")]
    Config(#[from] geth_config::ConfigError),
    #[error("crypto error: {0}")]
    Crypto(#[from] geth_crypto::CryptoError),
    #[error("store error: {0}")]
    Store(#[from] geth_store::StoreError),
    #[error("cas error: {0}")]
    Cas(#[from] geth_cas::CasError),
    #[error("control error: {0}")]
    Control(#[from] geth_control::ControlError),
    #[error("json error: {0}")]
    Json(#[from] serde_json::Error),
    #[error("io error: {0}")]
    Io(#[from] std::io::Error),
    #[error("invalid resource kind: {0}")]
    InvalidResourceKind(String),
    #[error("invalid ssh certificate kind: {0}")]
    InvalidSshCertKind(String),
    #[error("invalid ssh certificate request status: {0}")]
    InvalidSshCertStatus(String),
    #[error("invalid ssh revocation kind: {0}")]
    InvalidSshRevocationKind(String),
    #[error("ssh certificate request not found: {0}")]
    SshCertRequestNotFound(String),
    #[error("ssh certificate request must include at least one principal")]
    MissingSshCertPrincipal,
    #[error("ssh certificate flow error: {0}")]
    SshCertFlow(#[from] geth_ssh_identity::SshCertFlowError),
}

#[derive(Clone, Debug)]
pub struct LocalNode {
    pub paths: GethPaths,
    pub agent_id: String,
    pub node_id: String,
    pub iroh_status: EndpointStatus,
}

pub fn init_node(paths: &GethPaths) -> Result<LocalNode, NodeError> {
    paths.ensure_base_dirs()?;
    if !paths.config_file().exists() {
        std::fs::write(paths.config_file(), GethConfig::default_toml())?;
    }
    let key = AgentKey::load_or_create(&paths.agent_key())?;
    let agent_id = key.agent_id().to_string();
    let node_id = stable_node_id(&agent_id);
    let store = Store::open(&paths.metadata_db())?;
    store.upsert_agent(&agent_id, &key.public_key_hex())?;
    store.upsert_node(&node_id, "local", &agent_id)?;
    store.insert_resource(&StoredResource {
        resource_id: "resource:cas:local".to_owned(),
        kind: ResourceKind::Cas.to_string(),
        name: "local-cas".to_owned(),
        status: "active".to_owned(),
    })?;
    Ok(LocalNode {
        paths: paths.clone(),
        agent_id,
        node_id,
        iroh_status: EndpointStatus::scaffolded(),
    })
}

pub fn open_node(paths: &GethPaths) -> Result<LocalNode, NodeError> {
    init_node(paths)
}

pub async fn run_daemon(paths: GethPaths) -> Result<(), NodeError> {
    let mut node = init_node(&paths)?;
    let _iroh_endpoint = start_daemon_iroh_endpoint(&mut node).await?;
    if Path::new(&paths.socket_path()).exists() {
        std::fs::remove_file(paths.socket_path())?;
    }
    let listener = UnixListener::bind(paths.socket_path())?;
    tracing::info!(socket = %paths.socket_path().display(), "geth daemon listening");

    loop {
        let (stream, _) = listener.accept().await?;
        let node = node.clone();
        tokio::spawn(async move {
            if let Err(error) = handle_stream(node, stream).await {
                tracing::warn!(%error, "control request failed");
            }
        });
    }
}

pub async fn send_control(
    paths: &GethPaths,
    request: ControlRequest,
) -> Result<ControlResponse, NodeError> {
    let mut stream = UnixStream::connect(paths.socket_path()).await?;
    stream
        .write_all(geth_control::encode_request(&request)?.as_bytes())
        .await?;
    stream.shutdown().await?;
    let mut reader = BufReader::new(stream);
    let mut line = String::new();
    reader.read_line(&mut line).await?;
    Ok(geth_control::decode_response(&line)?)
}

async fn handle_stream(node: LocalNode, stream: UnixStream) -> Result<(), NodeError> {
    let mut reader = BufReader::new(stream);
    let mut line = String::new();
    reader.read_line(&mut line).await?;
    let request = geth_control::decode_request(&line)?;
    let response = match handle_request(&node, request) {
        Ok(response) => response,
        Err(error) => ControlResponse::Error {
            message: error.to_string(),
        },
    };
    let mut stream = reader.into_inner();
    stream
        .write_all(geth_control::encode_response(&response)?.as_bytes())
        .await?;
    Ok(())
}

pub fn handle_request(
    node: &LocalNode,
    request: ControlRequest,
) -> Result<ControlResponse, NodeError> {
    let store = Store::open(&node.paths.metadata_db())?;
    match request {
        ControlRequest::Status => Ok(ControlResponse::Status(StatusResponse {
            home: node.paths.home().to_path_buf(),
            socket: node.paths.socket_path(),
            agent_id: node.agent_id.clone(),
            node_id: node.node_id.clone(),
            iroh_enabled: node.iroh_status.enabled,
            endpoint_id: node.iroh_status.endpoint_id.clone(),
            iroh_relay_mode: node.iroh_status.relay_mode.clone(),
            iroh: node.iroh_status.note.clone(),
        })),
        ControlRequest::NodeId => Ok(ControlResponse::NodeId(NodeIdResponse {
            agent_id: node.agent_id.clone(),
            node_id: node.node_id.clone(),
            endpoint_id: node.iroh_status.endpoint_id.clone(),
        })),
        ControlRequest::ResourceList => Ok(ControlResponse::ResourceList {
            resources: store
                .list_resources()?
                .into_iter()
                .map(stored_resource_to_descriptor)
                .collect::<Result<Vec<_>, _>>()?,
        }),
        ControlRequest::ResourceCreate { kind, name } => {
            let kind = kind
                .parse::<ResourceKind>()
                .map_err(|_| NodeError::InvalidResourceKind(kind.clone()))?;
            let id = format!("resource:{}:{}", kind, name);
            let stored = StoredResource {
                resource_id: id,
                kind: kind.to_string(),
                name,
                status: "active".to_owned(),
            };
            store.insert_resource(&stored)?;
            Ok(ControlResponse::ResourceCreated {
                resource: stored_resource_to_descriptor(stored)?,
            })
        }
        ControlRequest::CasAdd { path } => {
            let cas = LocalCas::new(node.paths.cas_dir());
            let info = cas.add_path(&path)?;
            store.record_cas_object(
                info.hash.as_str(),
                info.size_bytes,
                &info.path.to_string_lossy(),
            )?;
            Ok(ControlResponse::CasAdded {
                hash: info.hash,
                size_bytes: info.size_bytes,
            })
        }
        ControlRequest::CasGet { hash, out } => {
            let cas = LocalCas::new(node.paths.cas_dir());
            let size_bytes = cas.get_to_path(&hash, &out)?;
            Ok(ControlResponse::CasGot {
                hash,
                out,
                size_bytes,
            })
        }
        ControlRequest::CasHash { path } => Ok(ControlResponse::CasHash {
            hash: hash_path(&path)?,
        }),
        ControlRequest::CasHas { hash } => {
            let cas = LocalCas::new(node.paths.cas_dir());
            let present = cas.has(&hash)?;
            Ok(ControlResponse::CasHas { hash, present })
        }
        ControlRequest::CasList => {
            let cas = LocalCas::new(node.paths.cas_dir());
            Ok(ControlResponse::CasList {
                blobs: cas
                    .list()?
                    .into_iter()
                    .map(|blob| CasBlob {
                        hash: blob.hash,
                        size_bytes: blob.size_bytes,
                    })
                    .collect(),
            })
        }
        ControlRequest::KeychainStatus => {
            Ok(ControlResponse::KeychainStatus(KeychainStatusResponse {
                initialized: false,
                admin_keys: 0,
                users: 0,
                devices: 0,
                nodes: 1,
            }))
        }
        ControlRequest::AuthExplain {
            subject,
            resource,
            capability,
        } => {
            if store.get_peer_card(&subject)?.is_some() {
                Ok(ControlResponse::AuthExplain(
                    AuthExplanation::discovered_candidate(subject, resource, capability),
                ))
            } else {
                Ok(ControlResponse::AuthExplain(AuthExplanation::stub(
                    subject, resource, capability,
                )))
            }
        }
        ControlRequest::SshCertRequest {
            public_key_path,
            cert_kind,
            principals,
            requested_validity,
            renewal_of,
            reason,
        } => {
            if principals.is_empty() {
                return Err(NodeError::MissingSshCertPrincipal);
            }
            let cert_kind = cert_kind
                .parse::<SshCertKind>()
                .map_err(|_| NodeError::InvalidSshCertKind(cert_kind.clone()))?;
            let public_key = std::fs::read_to_string(&public_key_path)?;
            let created_at = UnixMillis(geth_store::now_ms());
            let request = SshCertRequest {
                id: cert_request_id(
                    &NodeId::new(node.node_id.clone()),
                    &public_key,
                    &principals,
                    created_at,
                ),
                requester_node: NodeId::new(node.node_id.clone()),
                public_key_fingerprint: ssh_public_key_fingerprint(&public_key),
                public_key,
                cert_kind,
                principals,
                requested_validity,
                renewal_of: renewal_of.map(SshCertId::new),
                reason,
                status: SshCertRequestStatus::Pending,
                created_at,
            };
            store.insert_ssh_cert_request(&stored_from_ssh_cert_request(&request))?;
            Ok(ControlResponse::SshCertRequested { request })
        }
        ControlRequest::SshCertRequests => Ok(ControlResponse::SshCertRequests {
            requests: store
                .list_ssh_cert_requests()?
                .into_iter()
                .map(ssh_cert_request_from_stored)
                .collect::<Result<Vec<_>, _>>()?,
        }),
        ControlRequest::SshCertApprove {
            request_id,
            ca_key_path,
            valid_for,
            serial,
            out,
        } => {
            let stored = store
                .get_ssh_cert_request(&request_id)?
                .ok_or_else(|| NodeError::SshCertRequestNotFound(request_id.clone()))?;
            let mut request = ssh_cert_request_from_stored(stored)?;
            request.status = SshCertRequestStatus::Approved;
            store.update_ssh_cert_request_status(request.id.as_str(), request.status.as_str())?;
            let public_key_path = out.clone().unwrap_or_else(|| {
                node.paths
                    .home()
                    .join("ssh-cert-requests")
                    .join(format!("{}.pub", request.id))
            });
            if let Some(parent) = public_key_path.parent() {
                std::fs::create_dir_all(parent)?;
            }
            std::fs::write(&public_key_path, &request.public_key)?;
            let valid_for = valid_for
                .or_else(|| request.requested_validity.clone())
                .unwrap_or_else(|| "+52w".to_owned());
            let signing_command = build_ssh_cert_sign_command(
                &request,
                &ca_key_path,
                &public_key_path,
                &valid_for,
                serial,
            )?;
            let approval = SshCertApproval {
                request_id: request.id,
                approved_by_node: NodeId::new(node.node_id.clone()),
                ca_key_path: ca_key_path.display().to_string(),
                key_id: request_id,
                valid_for,
                serial,
                output_path: Some(expected_openssh_cert_path(&public_key_path)),
                signing_command,
                note: "request approved; run the signing command on the CA/YubiKey machine, then import the resulting -cert.pub file".to_owned(),
            };
            Ok(ControlResponse::SshCertApproved { approval })
        }
        ControlRequest::SshCertImport {
            request_id,
            cert_path,
        } => {
            let certificate = std::fs::read_to_string(&cert_path)?;
            let record = SshCertificateRecord {
                id: certificate_id(&certificate),
                request_id: SshCertRequestId::new(request_id.clone()),
                certificate_fingerprint: ssh_public_key_fingerprint(&certificate),
                certificate,
                imported_at: UnixMillis(geth_store::now_ms()),
            };
            store.insert_ssh_certificate(&stored_from_ssh_certificate(&record))?;
            store.update_ssh_cert_request_status(
                &request_id,
                SshCertRequestStatus::Signed.as_str(),
            )?;
            Ok(ControlResponse::SshCertImported {
                certificate: record,
            })
        }
        ControlRequest::SshCertList => Ok(ControlResponse::SshCertList {
            requests: store
                .list_ssh_cert_requests()?
                .into_iter()
                .map(ssh_cert_request_from_stored)
                .collect::<Result<Vec<_>, _>>()?,
            certificates: store
                .list_ssh_certificates()?
                .into_iter()
                .map(ssh_certificate_from_stored)
                .collect(),
        }),
        ControlRequest::SshRevocationAdd {
            kind,
            target,
            reason,
        } => {
            let kind = kind
                .parse::<SshRevocationKind>()
                .map_err(|_| NodeError::InvalidSshRevocationKind(kind.clone()))?;
            let created_at = UnixMillis(geth_store::now_ms());
            let revocation = SshRevocationEntry {
                id: revocation_id(&kind, &target, created_at),
                kind,
                target,
                reason,
                created_at,
                published: true,
            };
            store.insert_ssh_revocation(&stored_from_ssh_revocation(&revocation))?;
            Ok(ControlResponse::SshRevocationAdded { revocation })
        }
        ControlRequest::SshRevocationList => Ok(ControlResponse::SshRevocationList {
            revocations: store
                .list_ssh_revocations()?
                .into_iter()
                .map(ssh_revocation_from_stored)
                .collect::<Result<Vec<_>, _>>()?,
        }),
        ControlRequest::SshRevocationExport { out } => {
            let revocations = store
                .list_ssh_revocations()?
                .into_iter()
                .map(ssh_revocation_from_stored)
                .collect::<Result<Vec<_>, _>>()?;
            if let Some(parent) = out.parent() {
                std::fs::create_dir_all(parent)?;
            }
            let mut body = String::new();
            for revocation in &revocations {
                body.push_str(&serde_json::to_string(revocation)?);
                body.push('\n');
            }
            std::fs::write(&out, body)?;
            Ok(ControlResponse::SshRevocationExported {
                out,
                count: revocations.len(),
            })
        }
        ControlRequest::ModuleStub { module, command } => {
            Ok(ControlResponse::NotImplemented { module, command })
        }
    }
}

fn stored_resource_to_descriptor(stored: StoredResource) -> Result<ResourceDescriptor, NodeError> {
    let kind = stored
        .kind
        .parse::<ResourceKind>()
        .map_err(|_| NodeError::InvalidResourceKind(stored.kind.clone()))?;
    Ok(ResourceDescriptor::local(
        ResourceId::new(stored.resource_id),
        kind,
        ResourceName::new(stored.name),
    ))
}

fn stable_node_id(agent_id: &str) -> String {
    format!("node:{agent_id}")
}

async fn start_daemon_iroh_endpoint(
    node: &mut LocalNode,
) -> Result<Option<GethIrohEndpoint>, NodeError> {
    let node_config = GethConfig::load(&node.paths.config_file())?;
    let relay_mode = node_config.iroh.relay_mode;
    let iroh_relay_mode = config_relay_mode_to_iroh(relay_mode);
    let config = GethIrohConfig::local_with_relay(node.paths.iroh_key(), iroh_relay_mode);
    match geth_iroh::start_endpoint(&config).await {
        Ok(endpoint) => {
            let status = endpoint.status();
            if let Some(endpoint_id) = &status.endpoint_id {
                let store = Store::open(&node.paths.metadata_db())?;
                store.upsert_node_endpoint(endpoint_id, &node.node_id, &node.agent_id, "iroh")?;
            }
            node.iroh_status = status;
            Ok(Some(endpoint))
        }
        Err(error) => {
            node.iroh_status = EndpointStatus {
                enabled: false,
                endpoint_id: None,
                relay_mode: relay_mode.as_str().to_owned(),
                note: format!("Iroh endpoint failed to start: {error}"),
            };
            Ok(None)
        }
    }
}

fn config_relay_mode_to_iroh(mode: RelayMode) -> GethRelayMode {
    match mode {
        RelayMode::Disabled => GethRelayMode::Disabled,
        RelayMode::Default => GethRelayMode::Default,
        RelayMode::Staging => GethRelayMode::Staging,
    }
}

fn expected_openssh_cert_path(public_key_path: &Path) -> String {
    let text = public_key_path.display().to_string();
    if let Some(prefix) = text.strip_suffix(".pub") {
        format!("{prefix}-cert.pub")
    } else {
        format!("{text}-cert.pub")
    }
}

fn stored_from_ssh_cert_request(request: &SshCertRequest) -> StoredSshCertRequest {
    StoredSshCertRequest {
        request_id: request.id.to_string(),
        requester_node: request.requester_node.to_string(),
        public_key: request.public_key.clone(),
        public_key_fingerprint: request.public_key_fingerprint.clone(),
        cert_kind: request.cert_kind.to_string(),
        principals: request.principals.clone(),
        requested_validity: request.requested_validity.clone(),
        renewal_of: request.renewal_of.as_ref().map(ToString::to_string),
        reason: request.reason.clone(),
        status: request.status.to_string(),
        created_at_ms: request.created_at.0,
    }
}

fn ssh_cert_request_from_stored(stored: StoredSshCertRequest) -> Result<SshCertRequest, NodeError> {
    let cert_kind = stored
        .cert_kind
        .parse::<SshCertKind>()
        .map_err(|_| NodeError::InvalidSshCertKind(stored.cert_kind.clone()))?;
    let status = stored
        .status
        .parse::<SshCertRequestStatus>()
        .map_err(|_| NodeError::InvalidSshCertStatus(stored.status.clone()))?;
    Ok(SshCertRequest {
        id: SshCertRequestId::new(stored.request_id),
        requester_node: NodeId::new(stored.requester_node),
        public_key: stored.public_key,
        public_key_fingerprint: stored.public_key_fingerprint,
        cert_kind,
        principals: stored.principals,
        requested_validity: stored.requested_validity,
        renewal_of: stored.renewal_of.map(SshCertId::new),
        reason: stored.reason,
        status,
        created_at: UnixMillis(stored.created_at_ms),
    })
}

fn stored_from_ssh_certificate(certificate: &SshCertificateRecord) -> StoredSshCertificate {
    StoredSshCertificate {
        cert_id: certificate.id.to_string(),
        request_id: certificate.request_id.to_string(),
        certificate: certificate.certificate.clone(),
        certificate_fingerprint: certificate.certificate_fingerprint.clone(),
        imported_at_ms: certificate.imported_at.0,
    }
}

fn ssh_certificate_from_stored(stored: StoredSshCertificate) -> SshCertificateRecord {
    SshCertificateRecord {
        id: SshCertId::new(stored.cert_id),
        request_id: SshCertRequestId::new(stored.request_id),
        certificate: stored.certificate,
        certificate_fingerprint: stored.certificate_fingerprint,
        imported_at: UnixMillis(stored.imported_at_ms),
    }
}

fn stored_from_ssh_revocation(revocation: &SshRevocationEntry) -> StoredSshRevocation {
    StoredSshRevocation {
        revocation_id: revocation.id.to_string(),
        kind: revocation.kind.to_string(),
        target: revocation.target.clone(),
        reason: revocation.reason.clone(),
        created_at_ms: revocation.created_at.0,
        published: revocation.published,
    }
}

fn ssh_revocation_from_stored(
    stored: StoredSshRevocation,
) -> Result<SshRevocationEntry, NodeError> {
    let kind = stored
        .kind
        .parse::<SshRevocationKind>()
        .map_err(|_| NodeError::InvalidSshRevocationKind(stored.kind.clone()))?;
    Ok(SshRevocationEntry {
        id: geth_types::SshRevocationId::new(stored.revocation_id),
        kind,
        target: stored.target,
        reason: stored.reason,
        created_at: UnixMillis(stored.created_at_ms),
        published: stored.published,
    })
}