//! End-to-end tests of the loopback server.
//!
//! The Zagros test syncs the live testnet, so it is ignored by default. Run it with the chain
//! specifications of the relay chain and People:
//!
//! ```sh
//! PEZKUWI_LIGHT_RELAY_SPEC=zagros.json PEZKUWI_LIGHT_PEOPLE_SPEC=people-zagros.json \
//!     cargo test --release -- --ignored --nocapture
//! ```

use pezkuwi_light::{engine::Engine, platform::SystemResolver};
use std::{
    net::TcpStream,
    sync::Arc,
    time::{Duration, Instant},
};
use tungstenite::{stream::MaybeTlsStream, Message, WebSocket};

type Socket = WebSocket<MaybeTlsStream<TcpStream>>;

fn temporary_dir(name: &str) -> std::path::PathBuf {
    let dir = std::env::temp_dir().join(format!("pezkuwi-light-{name}-{}", std::process::id()));
    let _ = std::fs::remove_dir_all(&dir);
    dir
}

fn start(db_dir: std::path::PathBuf) -> Engine {
    // RUST_LOG=... shows smoldot's own timeline when a measurement needs explaining.
    let _ = env_logger::builder().format_timestamp_millis().is_test(true).try_init();
    Engine::start(db_dir, Arc::new(SystemResolver)).unwrap()
}

/// Connects to the loopback server; a read that waits longer than a sync can take fails the test
/// instead of hanging it.
fn connect(url: String) -> Socket {
    let (socket, _) = tungstenite::connect(url).unwrap();
    if let MaybeTlsStream::Plain(stream) = socket.get_ref() {
        stream.set_read_timeout(Some(Duration::from_secs(180))).unwrap();
    }
    socket
}

fn rpc(socket: &mut Socket, id: u64, method: &str, params: serde_json::Value) {
    let request = serde_json::json!({"jsonrpc": "2.0", "id": id, "method": method, "params": params});
    socket.send(Message::Text(request.to_string())).unwrap();
}

fn next_json(socket: &mut Socket) -> serde_json::Value {
    loop {
        if let Message::Text(text) = socket.read().unwrap() {
            return serde_json::from_str(&text).unwrap();
        }
    }
}

fn answer(socket: &mut Socket, id: u64) -> serde_json::Value {
    loop {
        let message = next_json(socket);
        if message["id"] == id {
            return message;
        }
    }
}

/// `Vec<u8>` SCALE encoding: compact length, then the bytes.
fn scale_bytes(bytes: &[u8]) -> String {
    assert!(bytes.len() < 64, "single-byte compact length only");
    format!("0x{:02x}{}", (bytes.len() as u8) << 2, hex::encode(bytes))
}

/// Established TCP connections of this process to anything but the loopback interface (Linux).
fn peer_connections() -> usize {
    let inodes: std::collections::HashSet<String> = std::fs::read_dir("/proc/self/fd")
        .unwrap()
        .filter_map(|fd| std::fs::read_link(fd.ok()?.path()).ok())
        .filter_map(|target| {
            let target = target.to_string_lossy().into_owned();
            Some(target.strip_prefix("socket:[")?.strip_suffix(']')?.to_owned())
        })
        .collect();
    ["/proc/net/tcp", "/proc/net/tcp6"]
        .iter()
        .flat_map(|table| std::fs::read_to_string(table).unwrap_or_default().lines().skip(1).map(str::to_owned).collect::<Vec<_>>())
        .filter(|line| {
            let fields: Vec<&str> = line.split_whitespace().collect();
            let remote = fields[2];
            let loopback = remote.starts_with("0100007F") || remote.starts_with("00000000000000000000000001000000");
            fields[3] == "01" && !loopback && inodes.contains(fields[9])
        })
        .count()
}

#[test]
fn a_path_without_the_token_is_refused() {
    let engine = start(temporary_dir("refused"));
    let base = engine.base_url();
    let (_, token) = base.rsplit_once('/').unwrap();
    let wrong = format!("{}{}", &token[..token.len() - 1], if token.ends_with('0') { '1' } else { '0' });
    let port = base.split(':').nth(2).unwrap().split('/').next().unwrap();

    for url in [
        format!("ws://127.0.0.1:{port}/{wrong}/relay"),
        format!("ws://127.0.0.1:{port}/relay"),
        // The token is right but no chain is registered under the key.
        format!("{base}/relay"),
    ] {
        match tungstenite::connect(&url) {
            Err(tungstenite::Error::Http(response)) => assert_eq!(response.status(), 404, "{url}"),
            other => panic!("{url} was not refused: {:?}", other.map(|_| ())),
        }
    }
}

#[test]
#[ignore = "syncs the live Zagros testnet; needs PEZKUWI_LIGHT_RELAY_SPEC and PEZKUWI_LIGHT_PEOPLE_SPEC"]
fn resolves_kurd_names_on_zagros_people() {
    let relay = std::fs::read_to_string(std::env::var("PEZKUWI_LIGHT_RELAY_SPEC").unwrap()).unwrap();
    let people = std::fs::read_to_string(std::env::var("PEZKUWI_LIGHT_PEOPLE_SPEC").unwrap()).unwrap();
    let db_dir = temporary_dir("zagros");
    let started = Instant::now();

    let engine = start(db_dir.clone());
    engine.add_chain("relay", &relay, None).unwrap();
    engine.add_chain("people", &people, Some("relay")).unwrap();
    assert!(engine.add_chain("people", &people, Some("relay")).is_err());

    let mut socket = connect(format!("{}/people", engine.base_url()));
    rpc(&mut socket, 1, "chain_subscribeFinalizedHeads", serde_json::json!([]));
    loop {
        if next_json(&mut socket).pointer("/params/result/number").is_some() {
            break;
        }
    }
    println!("first verified People head after {:.1}s", started.elapsed().as_secs_f64());
    let synced_at = std::time::SystemTime::now();

    // Registered on Zagros People by the Meclis grant of 2026-10-31: Governance-owned, active,
    // official. The full node answers the same bytes.
    rpc(&mut socket, 2, "state_call", serde_json::json!(["NavnisanApi_resolve", scale_bytes(b"dks.kurd")]));
    let resolved = answer(&mut socket, 2)["result"].as_str().unwrap().to_owned();
    assert!(
        resolved.starts_with("0x0195c0de27b9a054a3a68cf2bb26abf99071ad46c2485295bb4120185a811a042f"),
        "{resolved}"
    );

    rpc(&mut socket, 3, "state_call", serde_json::json!(["NavnisanApi_resolve", scale_bytes(b"yok-boyle-bir-ad.kurd")]));
    assert_eq!(answer(&mut socket, 3)["result"], "0x00");

    // A second connection to the same chain shares the sync and answers at once.
    let mut second = connect(format!("{}/people", engine.base_url()));
    let asked = Instant::now();
    rpc(&mut second, 4, "state_call", serde_json::json!(["NavnisanApi_resolve", scale_bytes(b"dks.kurd")]));
    assert_eq!(answer(&mut second, 4)["result"].as_str().unwrap(), resolved);
    println!("second connection answered in {:.2}s", asked.elapsed().as_secs_f64());

    // The finalized state is saved for the next start: a save made after the first verified
    // head, from which a new client resumes.
    let deadline = Instant::now() + Duration::from_secs(150);
    for file in ["relay.db", "people.db"] {
        let path = db_dir.join(file);
        while std::fs::metadata(&path).and_then(|m| m.modified()).map_or(true, |at| at < synced_at) {
            assert!(Instant::now() < deadline, "{file} was not saved after the sync");
            std::thread::sleep(Duration::from_millis(500));
        }
        println!("{file}: {} bytes", std::fs::metadata(&path).unwrap().len());
    }

    let restarted = Instant::now();
    let warm = start(db_dir);
    warm.add_chain("relay", &relay, None).unwrap();
    warm.add_chain("people", &people, Some("relay")).unwrap();
    let mut socket = connect(format!("{}/people", warm.base_url()));
    rpc(&mut socket, 5, "state_call", serde_json::json!(["NavnisanApi_resolve", scale_bytes(b"dks.kurd")]));
    assert_eq!(answer(&mut socket, 5)["result"].as_str().unwrap(), resolved);
    println!("warm start resolved after {:.1}s", restarted.elapsed().as_secs_f64());
}

/// Replaces a specification's boot nodes.
fn with_boot_nodes(spec: &str, boot_nodes: &[&str]) -> String {
    let mut spec: serde_json::Value = serde_json::from_str(spec).unwrap();
    spec["bootNodes"] = serde_json::json!(boot_nodes);
    spec.to_string()
}

#[test]
#[ignore = "syncs the live Zagros testnet; needs PEZKUWI_LIGHT_RELAY_SPEC and PEZKUWI_LIGHT_PEOPLE_SPEC"]
fn syncs_zagros_over_secure_websockets_only() {
    // The `/wss` boot nodes of 2026-10-31: nginx on 443 in front of each node's WebSocket port.
    let relay = with_boot_nodes(
        &std::fs::read_to_string(std::env::var("PEZKUWI_LIGHT_RELAY_SPEC").unwrap()).unwrap(),
        &[
            "/dns/zagros-bootnode-0.pezkuwichain.io/tcp/443/wss/p2p/12D3KooWHKMr39ubvsigZXdVJzr7nnMp5YTzMywKuTzPDo3Xf1tZ",
            "/dns/zagros-bootnode-1.pezkuwichain.io/tcp/443/wss/p2p/12D3KooWH6tzPuoFeyf8n6gNmus9Q3CdEGEVUvbduUnPTqJcLRLC",
        ],
    );
    let people = with_boot_nodes(
        &std::fs::read_to_string(std::env::var("PEZKUWI_LIGHT_PEOPLE_SPEC").unwrap()).unwrap(),
        &["/dns/zagros-people-bootnode.pezkuwichain.io/tcp/443/wss/p2p/12D3KooWLnDS5p5bvMzfco2BR4arKRbtpqoZwRvLKgCdzgVpuEQG"],
    );
    let started = Instant::now();
    let engine = start(temporary_dir("wss"));
    // Peers found through the DHT advertise plain TCP too; none of them may be used.
    engine.set_secure_only(true);
    engine.add_chain("relay", &relay, None).unwrap();
    engine.add_chain("people", &people, Some("relay")).unwrap();

    let mut socket = connect(format!("{}/people", engine.base_url()));
    rpc(&mut socket, 1, "state_call", serde_json::json!(["NavnisanApi_resolve", scale_bytes(b"dks.kurd")]));
    let resolved = answer(&mut socket, 1)["result"].as_str().unwrap().to_owned();
    assert!(
        resolved.starts_with("0x0195c0de27b9a054a3a68cf2bb26abf99071ad46c2485295bb4120185a811a042f"),
        "{resolved}"
    );
    println!("resolved over wss only after {:.1}s", started.elapsed().as_secs_f64());
}

/// Measures a start from a saved database in a process of its own, as an app launch is. The first
/// run with an empty `PEZKUWI_LIGHT_DB_DIR` syncs and waits for a save; later runs resume from it.
#[test]
#[ignore = "syncs the live Zagros testnet; needs PEZKUWI_LIGHT_RELAY_SPEC, PEZKUWI_LIGHT_PEOPLE_SPEC and PEZKUWI_LIGHT_DB_DIR"]
fn resolves_after_a_start_from_the_saved_database() {
    let relay = std::fs::read_to_string(std::env::var("PEZKUWI_LIGHT_RELAY_SPEC").unwrap()).unwrap();
    let people = std::fs::read_to_string(std::env::var("PEZKUWI_LIGHT_PEOPLE_SPEC").unwrap()).unwrap();
    let db_dir = std::path::PathBuf::from(std::env::var("PEZKUWI_LIGHT_DB_DIR").unwrap());
    let warm = db_dir.join("people.db").exists();
    let started = Instant::now();

    let engine = start(db_dir.clone());
    engine.add_chain("relay", &relay, None).unwrap();
    engine.add_chain("people", &people, Some("relay")).unwrap();
    let mut socket = connect(format!("{}/people", engine.base_url()));
    rpc(&mut socket, 1, "state_call", serde_json::json!(["NavnisanApi_resolve", scale_bytes(b"dks.kurd")]));
    let resolved = answer(&mut socket, 1)["result"].as_str().unwrap().to_owned();
    assert!(
        resolved.starts_with("0x0195c0de27b9a054a3a68cf2bb26abf99071ad46c2485295bb4120185a811a042f"),
        "{resolved}"
    );
    println!(
        "{} start resolved after {:.1}s",
        if warm { "warm" } else { "cold" },
        started.elapsed().as_secs_f64()
    );

    if !warm {
        let synced_at = std::time::SystemTime::now();
        let deadline = Instant::now() + Duration::from_secs(150);
        for file in ["relay.db", "people.db"] {
            let path = db_dir.join(file);
            while std::fs::metadata(&path).and_then(|m| m.modified()).map_or(true, |at| at < synced_at) {
                assert!(Instant::now() < deadline, "{file} was not saved after the sync");
                std::thread::sleep(Duration::from_millis(500));
            }
        }
    }
}

#[test]
#[ignore = "connects to the live Zagros testnet; needs PEZKUWI_LIGHT_RELAY_SPEC and PEZKUWI_LIGHT_PEOPLE_SPEC"]
fn a_removed_chain_stops_and_can_be_registered_again() {
    use pezkuwi_light::engine::Error;
    use std::sync::atomic::{AtomicBool, Ordering};

    // A panic on an executor thread would not fail the test by itself.
    static PANICKED: AtomicBool = AtomicBool::new(false);
    let default_hook = std::panic::take_hook();
    std::panic::set_hook(Box::new(move |info| {
        PANICKED.store(true, Ordering::SeqCst);
        default_hook(info);
    }));

    let relay = std::fs::read_to_string(std::env::var("PEZKUWI_LIGHT_RELAY_SPEC").unwrap()).unwrap();
    let people = std::fs::read_to_string(std::env::var("PEZKUWI_LIGHT_PEOPLE_SPEC").unwrap()).unwrap();
    let engine = start(temporary_dir("remove"));
    engine.add_chain("relay", &relay, None).unwrap();
    engine.add_chain("people", &people, Some("relay")).unwrap();
    let deadline = Instant::now() + Duration::from_secs(90);
    while peer_connections() == 0 {
        assert!(Instant::now() < deadline, "no peer connection was opened");
        std::thread::sleep(Duration::from_millis(500));
    }

    assert!(matches!(engine.remove_chain("relay"), Err(Error::RelayChainInUse(_))));
    engine.remove_chain("people").unwrap();
    engine.remove_chain("relay").unwrap();

    // Removing every chain alone left smoldot's network service, and its peer connections, open.
    // Connection attempts already under way finish first: about 20 s on Zagros.
    let deadline = Instant::now() + Duration::from_secs(60);
    while peer_connections() > 0 {
        assert!(Instant::now() < deadline, "peer connections outlived every chain");
        std::thread::sleep(Duration::from_secs(1));
    }
    assert!(matches!(engine.remove_chain("relay"), Err(Error::NotRegistered(_))));

    match tungstenite::connect(format!("{}/relay", engine.base_url())) {
        Err(tungstenite::Error::Http(response)) => assert_eq!(response.status(), 404),
        other => panic!("a removed chain was served: {:?}", other.map(|_| ())),
    }

    // Past the first database save of the removed chains, which must not reach smoldot.
    std::thread::sleep(Duration::from_secs(25));
    assert!(!PANICKED.load(Ordering::SeqCst), "a removed chain's database save panicked");

    engine.add_chain("relay", &relay, None).unwrap();
    let mut socket = connect(format!("{}/relay", engine.base_url()));
    rpc(&mut socket, 1, "chainSpec_v1_chainName", serde_json::json!([]));
    assert!(answer(&mut socket, 1)["result"].is_string());
}