// Copyright (c) 2019-2025 Provable Inc.
// This file is part of the snarkOS library.

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at:

// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#![forbid(unsafe_code)]

#[macro_use]
extern crate tracing;

mod helpers;
// Imports custom `Path` type, to be used instead of `axum`'s.
pub use helpers::*;

mod routes;

mod version;

use snarkos_node_cdn::CdnBlockSync;
use snarkos_node_consensus::Consensus;
use snarkos_node_router::{
    Routing,
    messages::{Message, UnconfirmedTransaction},
};
use snarkos_node_sync::BlockSync;
use snarkvm::{
    console::{program::ProgramID, types::Field},
    ledger::narwhal::Data,
    prelude::{Ledger, Network, cfg_into_iter, store::ConsensusStorage},
};

use anyhow::{Context, Result};
use axum::{
    body::Body,
    extract::{ConnectInfo, DefaultBodyLimit, Query, State},
    http::{Method, Request, StatusCode, header::CONTENT_TYPE},
    middleware,
    response::Response,
    routing::{get, post},
};
use axum_extra::response::ErasedJson;
#[cfg(feature = "locktick")]
use locktick::parking_lot::Mutex;
#[cfg(not(feature = "locktick"))]
use parking_lot::Mutex;
use std::{
    net::SocketAddr,
    sync::{Arc, atomic::AtomicUsize},
};
use tokio::{net::TcpListener, task::JoinHandle};
use tower_governor::{GovernorLayer, governor::GovernorConfigBuilder};
use tower_http::{
    cors::{Any, CorsLayer},
    trace::TraceLayer,
};

/// The default port used for the REST API
pub const DEFAULT_REST_PORT: u16 = 3030;

/// The API version prefixes.
pub const API_VERSION_V1: &str = "v1";
pub const API_VERSION_V2: &str = "v2";

/// A REST API server for the ledger.
#[derive(Clone)]
pub struct Rest<N: Network, C: ConsensusStorage<N>, R: Routing<N>> {
    /// CDN sync (only if node is using the CDN to sync).
    cdn_sync: Option<Arc<CdnBlockSync>>,
    /// The consensus module.
    consensus: Option<Consensus<N>>,
    /// The ledger.
    ledger: Ledger<N, C>,
    /// The node (routing).
    routing: Arc<R>,
    /// The server handles.
    handles: Arc<Mutex<Vec<JoinHandle<()>>>>,
    /// A reference to BlockSync,
    block_sync: Arc<BlockSync<N>>,
    /// The number of ongoing deploy transaction verifications via REST.
    num_verifying_deploys: Arc<AtomicUsize>,
    /// The number of ongoing execute transaction verifications via REST.
    num_verifying_executions: Arc<AtomicUsize>,
    /// The number of ongoing solution verifications via REST.
    num_verifying_solutions: Arc<AtomicUsize>,
}

impl<N: Network, C: 'static + ConsensusStorage<N>, R: Routing<N>> Rest<N, C, R> {
    /// Initializes a new instance of the server.
    pub async fn start(
        rest_ip: SocketAddr,
        rest_rps: u32,
        consensus: Option<Consensus<N>>,
        ledger: Ledger<N, C>,
        routing: Arc<R>,
        cdn_sync: Option<Arc<CdnBlockSync>>,
        block_sync: Arc<BlockSync<N>>,
    ) -> Result<Self> {
        // Initialize the server.
        let mut server = Self {
            consensus,
            ledger,
            routing,
            cdn_sync,
            block_sync,
            handles: Default::default(),
            num_verifying_deploys: Default::default(),
            num_verifying_executions: Default::default(),
            num_verifying_solutions: Default::default(),
        };
        // Spawn the server.
        server.spawn_server(rest_ip, rest_rps).await?;
        // Return the server.
        Ok(server)
    }
}

impl<N: Network, C: ConsensusStorage<N>, R: Routing<N>> Rest<N, C, R> {
    /// Returns the ledger.
    pub const fn ledger(&self) -> &Ledger<N, C> {
        &self.ledger
    }

    /// Returns the handles.
    pub const fn handles(&self) -> &Arc<Mutex<Vec<JoinHandle<()>>>> {
        &self.handles
    }
}

impl<N: Network, C: ConsensusStorage<N>, R: Routing<N>> Rest<N, C, R> {
    fn build_routes(&self, rest_rps: u32) -> axum::Router {
        let cors = CorsLayer::new()
            .allow_origin(Any)
            .allow_methods([Method::GET, Method::POST, Method::OPTIONS])
            .allow_headers([CONTENT_TYPE]);

        // Prepare the rate limiting setup.
        let governor_config = Box::new(
            GovernorConfigBuilder::default()
                .per_nanosecond((1_000_000_000 / rest_rps) as u64)
                .burst_size(rest_rps)
                .error_handler(|error| {
                    // Properly return a 429 Too Many Requests error
                    let error_message = error.to_string();
                    let mut response = Response::new(error_message.clone().into());
                    *response.status_mut() = StatusCode::INTERNAL_SERVER_ERROR;
                    if error_message.contains("Too Many Requests") {
                        *response.status_mut() = StatusCode::TOO_MANY_REQUESTS;
                    }
                    response
                })
                .finish()
                .expect("Couldn't set up rate limiting for the REST server!"),
        );

        let routes = axum::Router::new()

            // All the endpoints before the call to `route_layer` are protected with JWT auth.
            .route("/node/address", get(Self::get_node_address))
            .route("/program/{id}/mapping/{name}", get(Self::get_mapping_values))
            .route("/db_backup", post(Self::db_backup))
            .route_layer(middleware::from_fn(auth_middleware))

             // Get ../consensus_version
            .route("/consensus_version", get(Self::get_consensus_version))

            // GET ../block/..
            .route("/block/height/latest", get(Self::get_block_height_latest))
            .route("/block/hash/latest", get(Self::get_block_hash_latest))
            .route("/block/latest", get(Self::get_block_latest))
            .route("/block/{height_or_hash}", get(Self::get_block))
            // The path param here is actually only the height, but the name must match the route
            // above, otherwise there'll be a conflict at runtime.
            .route("/block/{height_or_hash}/header", get(Self::get_block_header))
            .route("/block/{height_or_hash}/transactions", get(Self::get_block_transactions))

            // GET and POST ../transaction/..
            .route("/transaction/{id}", get(Self::get_transaction))
            .route("/transaction/confirmed/{id}", get(Self::get_confirmed_transaction))
            .route("/transaction/unconfirmed/{id}", get(Self::get_unconfirmed_transaction))
            .route("/transaction/broadcast", post(Self::transaction_broadcast))

            // POST ../solution/broadcast
            .route("/solution/broadcast", post(Self::solution_broadcast))

            // GET ../find/..
            .route("/find/blockHash/{tx_id}", get(Self::find_block_hash))
            .route("/find/blockHeight/{state_root}", get(Self::find_block_height_from_state_root))
            .route("/find/transactionID/deployment/{program_id}", get(Self::find_latest_transaction_id_from_program_id))
            .route("/find/transactionID/deployment/{program_id}/{edition}", get(Self::find_transaction_id_from_program_id_and_edition))
            .route("/find/transactionID/{transition_id}", get(Self::find_transaction_id_from_transition_id))
            .route("/find/transitionID/{input_or_output_id}", get(Self::find_transition_id))

            // GET ../peers/..
            .route("/peers/count", get(Self::get_peers_count))
            .route("/peers/all", get(Self::get_peers_all))
            .route("/peers/all/metrics", get(Self::get_peers_all_metrics))

            // GET ../program/..
            .route("/program/{id}", get(Self::get_program))
            .route("/program/{id}/latest_edition", get(Self::get_latest_program_edition))
            .route("/program/{id}/{edition}", get(Self::get_program_for_edition))
            .route("/program/{id}/mappings", get(Self::get_mapping_names))
            .route("/program/{id}/mapping/{name}/{key}", get(Self::get_mapping_value))

            // GET ../sync/..
            // Note: keeping ../sync_status for compatibility
            .route("/sync_status", get(Self::get_sync_status))
            .route("/sync/status", get(Self::get_sync_status))
            .route("/sync/peers", get(Self::get_sync_peers))
            .route("/sync/requests", get(Self::get_sync_requests_summary))
            .route("/sync/requests/list", get(Self::get_sync_requests_list))

            // GET misc endpoints.
            .route("/version", get(Self::get_version))
            .route("/blocks", get(Self::get_blocks))
            .route("/height/{hash}", get(Self::get_height))
            .route("/memoryPool/transmissions", get(Self::get_memory_pool_transmissions))
            .route("/memoryPool/solutions", get(Self::get_memory_pool_solutions))
            .route("/memoryPool/transactions", get(Self::get_memory_pool_transactions))
            .route("/statePath/{commitment}", get(Self::get_state_path_for_commitment))
            .route("/statePaths", get(Self::get_state_paths_for_commitments))
            .route("/stateRoot/latest", get(Self::get_state_root_latest))
            .route("/stateRoot/{height}", get(Self::get_state_root))
            .route("/committee/latest", get(Self::get_committee_latest))
            .route("/committee/{height}", get(Self::get_committee))
            .route("/delegators/{validator}", get(Self::get_delegators_for_validator));

        // If the node is a validator and `telemetry` features is enabled, enable the additional endpoint.
        #[cfg(feature = "telemetry")]
        let routes = match self.consensus {
            Some(_) => routes.route("/validators/participation", get(Self::get_validator_participation_scores)),
            None => routes,
        };

        // If the `history` feature is enabled, enable the additional endpoint.
        #[cfg(feature = "history")]
        let routes = routes.route("/block/{blockHeight}/history/{mapping}", get(Self::get_history));

        routes
            // Pass in `Rest` to make things convenient.
            .with_state(self.clone())
            // Enable tower-http tracing.
            .layer(TraceLayer::new_for_http())
            // Custom logging.
            .layer(middleware::map_request(log_middleware))
            // Enable CORS.
            .layer(cors)
            // Cap the request body size at 512KiB.
            .layer(DefaultBodyLimit::max(512 * 1024))
            .layer(GovernorLayer {
                config: governor_config.into(),
            })
    }

    async fn spawn_server(&mut self, rest_ip: SocketAddr, rest_rps: u32) -> Result<()> {
        // Log the REST rate limit per IP.
        debug!("REST rate limit per IP - {rest_rps} RPS");

        // Add the v1 API as default and under "/v1".
        let default_router = axum::Router::new().nest(
            &format!("/{}", N::SHORT_NAME),
            self.build_routes(rest_rps).layer(middleware::map_response(v1_error_middleware)),
        );
        let v1_router = axum::Router::new().nest(
            &format!("/{API_VERSION_V1}/{}", N::SHORT_NAME),
            self.build_routes(rest_rps).layer(middleware::map_response(v1_error_middleware)),
        );

        // Add the v2 API under "/v2".
        let v2_router =
            axum::Router::new().nest(&format!("/{API_VERSION_V2}/{}", N::SHORT_NAME), self.build_routes(rest_rps));

        // Combine all routes.
        let router = default_router.merge(v1_router).merge(v2_router);

        let rest_listener =
            TcpListener::bind(rest_ip).await.with_context(|| "Failed to bind TCP port for REST endpoints")?;

        let handle = tokio::spawn(async move {
            axum::serve(rest_listener, router.into_make_service_with_connect_info::<SocketAddr>())
                .await
                .expect("couldn't start rest server");
        });

        self.handles.lock().push(handle);
        Ok(())
    }
}

/// Creates a log message for every HTTP request.
async fn log_middleware(ConnectInfo(addr): ConnectInfo<SocketAddr>, request: Request<Body>) -> Request<Body> {
    info!("Received '{} {}' from '{addr}'", request.method(), request.uri());
    request
}

/// Converts errors to the old style for the v1 API.
/// The error code will always be 500 and the content a simple string.
async fn v1_error_middleware(response: Response) -> Response {
    // The status code used by all v1 errors
    const V1_STATUS_CODE: StatusCode = StatusCode::INTERNAL_SERVER_ERROR;

    if response.status().is_success() {
        return response;
    }

    // Returns a opaque error instead of panicking.
    let fallback = || {
        let mut response = Response::new(Body::from("Failed to convert error"));
        *response.status_mut() = V1_STATUS_CODE;
        response
    };

    let Ok(bytes) = axum::body::to_bytes(response.into_body(), usize::MAX).await else {
        return fallback();
    };

    // Deserialize REST error so we can convert it to a string
    let Ok(json_err) = serde_json::from_slice::<SerializedRestError>(&bytes) else {
        return fallback();
    };

    let mut message = json_err.message;
    for next in json_err.chain.into_iter() {
        message = format!("{message} — {next}");
    }

    let mut response = Response::new(Body::from(message));

    *response.status_mut() = V1_STATUS_CODE;

    response
}

/// Formats an ID into a truncated identifier (for logging purposes).
pub fn fmt_id(id: impl ToString) -> String {
    let id = id.to_string();
    let mut formatted_id = id.chars().take(16).collect::<String>();
    if id.chars().count() > 16 {
        formatted_id.push_str("..");
    }
    formatted_id
}

#[cfg(test)]
mod tests {
    use super::*;
    use anyhow::anyhow;
    use axum::{
        Router,
        body::Body,
        http::{Request, StatusCode},
        middleware,
        routing::get,
    };
    use tower::ServiceExt; // for `oneshot`

    fn test_app() -> Router {
        let build_routes = || {
            Router::new()
                .route("/not_found", get(|| async { Err::<(), RestError>(RestError::not_found(anyhow!("missing"))) }))
                .route("/bad_request", get(|| async { Err::<(), RestError>(RestError::bad_request(anyhow!("bad"))) }))
                .route(
                    "/service_unavailable",
                    get(|| async { Err::<(), RestError>(RestError::service_unavailable(anyhow!("gone"))) }),
                )
        };
        let router_v1 = build_routes().route_layer(middleware::map_response(v1_error_middleware));
        let router_v2 = Router::new().nest(&format!("/{API_VERSION_V2}"), build_routes());
        router_v1.merge(router_v2)
    }

    #[tokio::test]
    async fn v1_routes_force_internal_server_error() {
        let app = test_app();

        let res = app.clone().oneshot(Request::builder().uri("/not_found").body(Body::empty()).unwrap()).await.unwrap();
        assert_eq!(res.status(), StatusCode::INTERNAL_SERVER_ERROR);

        let res =
            app.clone().oneshot(Request::builder().uri("/bad_request").body(Body::empty()).unwrap()).await.unwrap();
        assert_eq!(res.status(), StatusCode::INTERNAL_SERVER_ERROR);

        let res =
            app.oneshot(Request::builder().uri("/service_unavailable").body(Body::empty()).unwrap()).await.unwrap();
        assert_eq!(res.status(), StatusCode::INTERNAL_SERVER_ERROR);
    }

    #[tokio::test]
    async fn v2_routes_return_specific_errors() {
        let app = test_app();

        let res =
            app.clone().oneshot(Request::builder().uri("/v2/not_found").body(Body::empty()).unwrap()).await.unwrap();
        assert_eq!(res.status(), StatusCode::NOT_FOUND);

        let res =
            app.clone().oneshot(Request::builder().uri("/v2/bad_request").body(Body::empty()).unwrap()).await.unwrap();
        assert_eq!(res.status(), StatusCode::BAD_REQUEST);

        let res =
            app.oneshot(Request::builder().uri("/v2/service_unavailable").body(Body::empty()).unwrap()).await.unwrap();
        assert_eq!(res.status(), StatusCode::SERVICE_UNAVAILABLE);
    }
}
