zc2 0.0.25

//! VPN-join: connect zc to the zakuro WireGuard mesh.
//!
//! Public surface used by the rest of zc:
//!   - `connect(Preference) -> Result<ConnectionInfo, NetError>`
//!   - `status() -> Result<Option<ConnectionInfo>, NetError>`
//!   - `disconnect() -> Result<(), NetError>`
//!   - `run_cli(&[String])` — handler for `zc vpn …`
//!
//! Backends (native wg-quick / Docker sidecar) live behind the `Connector`
//! trait so each is testable in isolation.

#![allow(dead_code)]

pub mod connector;
pub mod docker;
pub mod native;
pub mod profile;
pub mod state;

use connector::{select_connector, Connector, Preference};
use serde::{Deserialize, Serialize};
use std::sync::atomic::{AtomicBool, Ordering};

/// Verbose diagnostics toggle for `zc vpn` (`--verbose`/`-v`). When on, the mesh
/// steps print backend selection, wg-quick output, and `wg show` so a failed
/// connect can be diagnosed without guessing.
static VERBOSE: AtomicBool = AtomicBool::new(false);
pub fn set_verbose(v: bool) {
    VERBOSE.store(v, Ordering::Relaxed);
}
pub fn verbose() -> bool {
    VERBOSE.load(Ordering::Relaxed)
}
/// Print a `[vpn]` diagnostic line to stderr, but only in verbose mode.
pub fn vlog(msg: &str) {
    if verbose() {
        eprintln!("  [vpn] {msg}");
    }
}

/// Which transport carried the tunnel.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum Backend {
    Native,
    Docker,
}

impl Backend {
    pub fn label(&self) -> &'static str {
        match self {
            Backend::Native => "native",
            Backend::Docker => "docker",
        }
    }
}

/// Liveness of a single mesh peer, as seen from this node.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PeerStatus {
    pub ip: String,
    pub last_handshake_secs: Option<u64>,
    pub reachable: bool,
}

/// The result of a successful connect / the current link state.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ConnectionInfo {
    pub backend: Backend,
    pub address: String, // e.g. "10.13.13.6/24"
    pub link: String,    // iface name (native) or container name (docker)
    pub peers: Vec<PeerStatus>,
    pub host_routable: bool,
    #[serde(default)]
    pub proxy: Option<String>, // "127.0.0.1:18888" when backend=Docker exposes a CONNECT proxy
}

/// How zc reaches the mesh subnet.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum MeshAccess {
    Host,
    Proxy(String), // host:port of the sidecar's HTTP CONNECT proxy
}

/// Errors surfaced by the vpn module.
#[derive(Debug)]
pub enum NetError {
    NoApiKey,
    Fetch(String),
    NoBackend,
    Backend(String),
    Profile(String),
}

impl std::fmt::Display for NetError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            NetError::NoApiKey => write!(f, "p2p requires ZAKURO_API_KEY (set it and retry)"),
            NetError::Fetch(e) => write!(f, "failed to fetch WireGuard profile: {}", e),
            NetError::NoBackend => {
                let hint = if cfg!(target_os = "macos") {
                    "install WireGuard (`brew install wireguard-tools wireguard-go`) then re-run with `sudo`, or start Docker Desktop"
                } else {
                    "install WireGuard (`sudo apt install wireguard-tools`) and run as root, or install Docker"
                };
                write!(f, "no usable backend: {hint}")
            }
            NetError::Backend(e) => write!(f, "tunnel backend error: {}", e),
            NetError::Profile(e) => write!(f, "invalid WireGuard profile: {}", e),
        }
    }
}

impl std::error::Error for NetError {}

/// Which access mode a live connection provides.
fn access_of(info: &ConnectionInfo) -> Result<MeshAccess, NetError> {
    match (&info.proxy, info.host_routable) {
        (_, true) => Ok(MeshAccess::Host),
        (Some(p), false) => Ok(MeshAccess::Proxy(p.clone())),
        (None, false) => Err(NetError::Backend(
            "tunnel up but host cannot route and no proxy available".into(),
        )),
    }
}

/// True when the tunnel has a recent WireGuard handshake with the mesh server —
/// the authoritative "am I on the mesh" signal. The wg server exposes no TCP
/// service on its mesh IP, so a port probe is meaningless; the handshake is not.
/// Runs `wg show <iface> latest-handshakes` on the host (native) or inside the
/// sidecar (docker), retrying to give a just-started tunnel time to handshake.
fn mesh_handshake_ok(info: &ConnectionInfo) -> bool {
    use std::time::{Duration, SystemTime, UNIX_EPOCH};
    let now = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map(|d| d.as_secs())
        .unwrap_or(0);
    for attempt in 0..5 {
        if attempt > 0 {
            std::thread::sleep(Duration::from_millis(1200));
        }
        let out = match info.backend {
            Backend::Native => std::process::Command::new("wg")
                .args(["show", "zakuro0", "latest-handshakes"])
                .output()
                .ok(),
            Backend::Docker => std::process::Command::new("docker")
                .args([
                    "exec",
                    &info.link,
                    "wg",
                    "show",
                    "zakuro0",
                    "latest-handshakes",
                ])
                .output()
                .ok(),
        };
        let text = match out {
            Some(o) if o.status.success() => String::from_utf8_lossy(&o.stdout).into_owned(),
            _ => continue,
        };
        // any peer with a handshake in the last 5 min counts as reachable
        let fresh = text
            .lines()
            .filter_map(|l| l.split_whitespace().nth(1))
            .filter_map(|s| s.parse::<u64>().ok())
            .any(|hs| hs > 0 && now.saturating_sub(hs) < 300);
        if fresh {
            return true;
        }
    }
    false
}

/// Testable core of `ensure`: the verify + connect functions are injected.
fn ensure_with(
    verify_fn: &dyn Fn(&ConnectionInfo) -> bool,
    connect_fn: &dyn Fn() -> Result<ConnectionInfo, NetError>,
    saved: Option<&ConnectionInfo>,
) -> Result<MeshAccess, NetError> {
    // 1./2. reuse a live path (host or container proxy) if it still verifies.
    if let Some(s) = saved {
        if verify_fn(s) {
            return access_of(s);
        }
    }
    // 3. bring it up, then 4. verify — no silent success.
    let info = connect_fn()?;
    if !verify_fn(&info) {
        return Err(NetError::Backend(
            "mesh probe failed — tunnel is up but no handshake with the mesh server".into(),
        ));
    }
    access_of(&info)
}

/// Verified mesh access: reuse a live path or bring the tunnel up, then verify
/// via the WireGuard handshake.
pub fn ensure(pref: Preference) -> Result<MeshAccess, NetError> {
    let saved = status()?; // None if stale/not running
    ensure_with(&mesh_handshake_ok, &|| connect(pref), saved.as_ref())
}

/// True for addresses inside the WireGuard mesh subnet 10.13.13.0/24.
pub fn is_mesh_ip(host: &str) -> bool {
    let p: Vec<&str> = host.split('.').collect();
    p.len() == 4 && p[0] == "10" && p[1] == "13" && p[2] == "13" && p[3].parse::<u8>().is_ok()
}

/// The sidecar CONNECT proxy address ("host:port") from saved state, if any.
/// Callers building their own `ureq::Agent` use this to route mesh traffic.
pub fn mesh_proxy_addr() -> Option<String> {
    state::load().and_then(|s| s.proxy)
}

/// The sidecar CONNECT proxy as a `ureq::Proxy`, for callers that assemble
/// their own agent config: `cfg.proxy(vpn::mesh_proxy())`. `None` when the
/// host routes into the mesh itself (native or hostnet docker) or when no
/// tunnel is recorded — a plain agent is then exactly right.
pub fn mesh_proxy() -> Option<ureq::Proxy> {
    mesh_proxy_addr().and_then(|p| ureq::Proxy::new(&format!("http://{}", p)).ok())
}

/// Ask the hub for the mesh's shared peer key and store it locally so a
/// broker started here (`zc share`, `zc broker`) can act as a full peer.
/// Best-effort: an older hub without `/api/broker/config/mesh` (404) or a
/// missing key is not an error — the tunnel is up either way, the broker
/// just stays a client of the mesh rather than a peer.
pub fn sync_mesh_peer_key() {
    crate::credentials::load_into_env();
    let Ok(api_key) = std::env::var("ZAKURO_API_KEY") else {
        return;
    };
    if api_key.trim().is_empty() {
        return;
    }
    let api_url = crate::credentials::default_api_url();
    let endpoint = format!("{}/api/broker/config/mesh", api_url.trim_end_matches('/'));
    let resp = match ureq::get(&endpoint)
        .config()
        .timeout_global(Some(std::time::Duration::from_secs(10)))
        .http_status_as_error(false)
        .build()
        .header("X-Broker-Api-Key", &api_key)
        .call()
    {
        Ok(r) => r,
        Err(e) => {
            vlog(&format!("mesh peer key: request failed ({e})"));
            return;
        }
    };
    let status = resp.status().as_u16();
    if status != 200 {
        vlog(&format!(
            "mesh peer key: hub answered HTTP {status}; not stored"
        ));
        return;
    }
    let Ok(text) = resp.into_body().read_to_string() else {
        return;
    };
    let key = serde_json::from_str::<serde_json::Value>(&text)
        .ok()
        .and_then(|v| {
            v.get("peer_key")
                .and_then(|k| k.as_str())
                .map(str::to_string)
        })
        .filter(|k| !k.trim().is_empty());
    match key {
        Some(k) => match crate::credentials::save_mesh_peer_key(&k) {
            Ok(()) => vlog("mesh peer key stored"),
            Err(e) => eprintln!("  ⚠ could not store the mesh peer key: {e}"),
        },
        None => vlog("mesh peer key: hub response carried no peer_key"),
    }
}

/// HTTP agent for mesh-bound requests: routed through the sidecar CONNECT
/// proxy when the saved connection has one, plain otherwise.
pub fn mesh_agent(timeout: std::time::Duration) -> ureq::Agent {
    let mut cfg = ureq::Agent::config_builder()
        .timeout_connect(Some(timeout))
        .timeout_global(Some(timeout));
    if let Some(saved) = state::load() {
        if let Some(p) = saved.proxy {
            if let Ok(proxy) = ureq::Proxy::new(&format!("http://{}", p)) {
                cfg = cfg.proxy(Some(proxy));
            }
        }
    }
    ureq::Agent::new_with_config(cfg.build())
}

/// Connect to the mesh using the given backend preference.
pub fn connect(pref: Preference) -> Result<ConnectionInfo, NetError> {
    // Idempotent: if a live connection is already recorded, refresh + return it.
    // The peer key is synced on THIS path too: a machine that connected before
    // the hub served the key (or before this build) would otherwise never get
    // it, and its broker would sit on the mesh unable to peer.
    if let Some(existing) = status()? {
        sync_mesh_peer_key();
        return Ok(existing);
    }
    let profile = profile::fetch_wg_profile()?;
    let connector = select_connector(pref)?;
    let info = connector.connect(&profile)?;
    // Same credential, same moment: a machine that can join the tunnel should
    // also be able to run a broker that peers on it.
    sync_mesh_peer_key();
    Ok(info)
}

/// Current connection (None if not connected).
pub fn status() -> Result<Option<ConnectionInfo>, NetError> {
    if let Some(saved) = state::load() {
        let c = select_for_backend(saved.backend);
        if let Ok(Some(info)) = c.status() {
            return Ok(Some(info));
        }
        return Ok(None);
    }
    // No state file. A live tunnel may still exist (the file was deleted, or a
    // different HOME/ZAKURO_STATE_DIR wrote it): adopt it from the backend —
    // the docker helper rebuilds its info from container labels — instead of
    // reporting "not connected" and letting `connect` tear a working tunnel
    // down to build the same one again.
    if let Ok(Some(info)) = docker::DockerConnector.status() {
        return Ok(Some(info));
    }
    if let Ok(Some(info)) = native::NativeConnector.status() {
        return Ok(Some(info));
    }
    Ok(None)
}

/// Fetch this node's WireGuard profile and render it as wg-quick conf text.
/// Lets a host hand the conf to an isolated VPN container (`zc vpn conf`)
/// without bringing up an interface itself.
pub fn conf() -> Result<String, NetError> {
    profile::fetch_wg_profile()?.to_conf()
}

/// Disconnect whichever backend is active.
pub fn disconnect() -> Result<(), NetError> {
    if let Some(saved) = state::load() {
        select_for_backend(saved.backend).disconnect()?;
    } else {
        // Best-effort: tear down both, ignore errors.
        let _ = docker::DockerConnector.disconnect();
        let _ = native::NativeConnector.disconnect();
    }
    Ok(())
}

fn select_for_backend(b: Backend) -> Box<dyn connector::Connector> {
    match b {
        Backend::Native => Box::new(native::NativeConnector),
        Backend::Docker => Box::new(docker::DockerConnector),
    }
}

fn parse_pref(args: &[String]) -> Preference {
    if args.iter().any(|a| a == "--native") {
        Preference::Native
    } else if args.iter().any(|a| a == "--docker") {
        Preference::Docker
    } else {
        Preference::Auto
    }
}

/// Render a one-line human summary of a connection.
fn render(info: &ConnectionInfo) -> String {
    let reachable = info.peers.iter().filter(|p| p.reachable).count();
    let access = match &info.proxy {
        Some(p) if !info.host_routable => format!("proxy {}", p),
        _ => "host".to_string(),
    };
    format!(
        "connected to zakuro mesh — {} · {} · {} peer(s), {} reachable · access: {}",
        info.address,
        info.backend.label(),
        info.peers.len(),
        reachable,
        access,
    )
}

/// CLI entry point for `zc vpn …`. `args` is everything after `vpn`.
pub fn run_cli(args: &[String]) {
    use colored::Colorize;
    set_verbose(args.iter().any(|a| a == "--verbose" || a == "-v"));
    let sub = args.first().map(|s| s.as_str()).unwrap_or("status");
    match sub {
        "connect" | "up" => match connect(parse_pref(args)) {
            Ok(info) => println!("  {} {}", "✓".green(), render(&info)),
            Err(e) => {
                eprintln!("  {} {}", "✗".red(), e);
                std::process::exit(1);
            }
        },
        "ensure" => match ensure(parse_pref(args)) {
            Ok(MeshAccess::Host) => {
                println!("  {} mesh verified via host tunnel", "✓".green())
            }
            Ok(MeshAccess::Proxy(p)) => {
                println!("  {} mesh verified via container proxy {}", "✓".green(), p)
            }
            Err(e) => {
                eprintln!("  {} {}", "✗".red(), e);
                std::process::exit(1);
            }
        },
        "disconnect" | "down" => match disconnect() {
            Ok(()) => println!("  {} disconnected from zakuro mesh", "✓".green()),
            Err(e) => {
                eprintln!("  {} {}", "✗".red(), e);
                std::process::exit(1);
            }
        },
        "status" => match status() {
            Ok(Some(info)) => println!("  {}", render(&info)),
            Ok(None) => println!("  not connected (local mode)"),
            Err(e) => {
                eprintln!("  {} {}", "✗".red(), e);
                std::process::exit(1);
            }
        },
        "conf" => match conf() {
            Ok(text) => print!("{}", text),
            Err(e) => {
                eprintln!("  {} {}", "✗".red(), e);
                std::process::exit(1);
            }
        },
        other => {
            eprintln!(
                "usage: zc vpn [connect [--native|--docker] | ensure | disconnect | status | conf] (got '{}')",
                other
            );
            std::process::exit(1);
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::vpn::connector::Preference;

    #[test]
    fn parse_pref_reads_flags() {
        assert_eq!(parse_pref(&["connect".into()]), Preference::Auto);
        assert_eq!(
            parse_pref(&["connect".into(), "--native".into()]),
            Preference::Native
        );
        assert_eq!(
            parse_pref(&["connect".into(), "--docker".into()]),
            Preference::Docker
        );
    }

    const SAMPLE_PROFILE: &str = r#"{
        "interface": { "private_key": "MKCl4DM7FbX1sFUiFd8VqKzdIGUMwJ28rTgFYezsclc=", "address": "10.13.13.6/24" },
        "peer": { "public_key": "/Lzp+YIUBrNgdABzyR221uhfx2uOWi4m5ZAdgxXzhFs=",
                  "endpoint": "144.202.121.242:51822", "allowed_ips": "10.13.13.0/24",
                  "persistent_keepalive": 25 }
    }"#;

    #[test]
    fn connection_info_proxy_roundtrip_and_default() {
        // old state files (no proxy key) still parse
        let legacy = r#"{"backend":"Docker","address":"10.13.13.6/24","link":"zakuro-wg",
                         "peers":[],"host_routable":false}"#;
        let info: ConnectionInfo = serde_json::from_str(legacy).unwrap();
        assert!(info.proxy.is_none());
        let with = ConnectionInfo {
            proxy: Some("127.0.0.1:18888".into()),
            ..info
        };
        let back: ConnectionInfo =
            serde_json::from_str(&serde_json::to_string(&with).unwrap()).unwrap();
        assert_eq!(back.proxy.as_deref(), Some("127.0.0.1:18888"));
    }

    #[test]
    fn ensure_ladder_reuse_host_reuse_proxy_then_connect() {
        use std::cell::Cell;
        // 1. saved native host connection that still verifies → Host (no connect)
        let native_saved = ConnectionInfo {
            backend: Backend::Native,
            address: "10.13.13.6/24".into(),
            link: "zakuro0".into(),
            peers: vec![],
            host_routable: true,
            proxy: None,
        };
        let r = ensure_with(&|_| true, &|| Err(NetError::NoBackend), Some(&native_saved)).unwrap();
        assert!(matches!(r, MeshAccess::Host));
        // 2. saved docker+proxy connection that still verifies → Proxy (no connect)
        let saved = ConnectionInfo {
            backend: Backend::Docker,
            address: "10.13.13.6/24".into(),
            link: "zakuro-wg".into(),
            peers: vec![],
            host_routable: false,
            proxy: Some("127.0.0.1:18888".into()),
        };
        let r = ensure_with(&|_| true, &|| Err(NetError::NoBackend), Some(&saved)).unwrap();
        assert!(matches!(r, MeshAccess::Proxy(ref p) if p == "127.0.0.1:18888"));
        // 3. saved no longer verifies → connect_fn runs; its result must verify too.
        //    verify keeps failing → Err (no silent success).
        let called = Cell::new(false);
        let err = ensure_with(
            &|_| false,
            &|| {
                called.set(true);
                Ok(saved.clone())
            },
            Some(&saved),
        )
        .unwrap_err();
        assert!(called.get());
        assert!(format!("{err}").contains("mesh probe failed"));
        // 4. fresh connect that verifies → Proxy
        let r = ensure_with(&|_| true, &|| Ok(saved.clone()), None).unwrap();
        assert!(matches!(r, MeshAccess::Proxy(_)));
    }

    #[test]
    fn mesh_ip_detection() {
        assert!(is_mesh_ip("10.13.13.4"));
        assert!(is_mesh_ip("10.13.13.254"));
        assert!(!is_mesh_ip("100.82.173.52")); // wireguard
        assert!(!is_mesh_ip("192.168.0.23"));
        assert!(!is_mesh_ip("10.13.14.4"));
        assert!(!is_mesh_ip("localhost"));
    }

    #[test]
    fn mesh_agent_uses_connect_proxy_when_state_has_one() {
        use std::io::{Read, Write};
        use std::net::TcpListener;
        // fake peer: replies to any HTTP request
        let peer = TcpListener::bind("127.0.0.1:0").unwrap();
        let peer_port = peer.local_addr().unwrap().port();
        std::thread::spawn(move || {
            for s in peer.incoming().flatten() {
                let mut s = s;
                let mut b = [0u8; 1024];
                let _ = s.read(&mut b);
                let _ = s.write_all(
                    b"HTTP/1.1 200 OK\r\nContent-Length: 2\r\nConnection: close\r\n\r\nok",
                );
            }
        });
        // mini CONNECT proxy: accepts CONNECT, tunnels to the fake peer
        let proxy = TcpListener::bind("127.0.0.1:0").unwrap();
        let proxy_addr = proxy.local_addr().unwrap();
        std::thread::spawn(move || {
            for c in proxy.incoming().flatten() {
                let mut c = c;
                // read the CONNECT request line + headers (loop until CRLFCRLF)
                let mut req = Vec::new();
                let mut b = [0u8; 256];
                loop {
                    match c.read(&mut b) {
                        Ok(0) | Err(_) => break,
                        Ok(n) => {
                            req.extend_from_slice(&b[..n]);
                            if req.windows(4).any(|w| w == b"\r\n\r\n") {
                                break;
                            }
                        }
                    }
                }
                // only a CONNECT to the mesh peer should ever arrive here
                if !String::from_utf8_lossy(&req).starts_with("CONNECT 10.13.13.9:9000") {
                    continue;
                }
                c.write_all(b"HTTP/1.1 200 Connection established\r\n\r\n")
                    .unwrap();
                let mut up = std::net::TcpStream::connect(("127.0.0.1", peer_port)).unwrap();
                let mut c2 = c.try_clone().unwrap();
                let mut up2 = up.try_clone().unwrap();
                std::thread::spawn(move || {
                    let _ = std::io::copy(&mut c2, &mut up);
                });
                let _ = std::io::copy(&mut up2, &mut c);
            }
        });
        // state with proxy → agent must route through it
        let dir = std::env::temp_dir().join(format!("zc-vpn-agent-{}", std::process::id()));
        std::fs::create_dir_all(&dir).unwrap();
        std::env::set_var("ZAKURO_STATE_DIR", &dir);
        state::save(&ConnectionInfo {
            backend: Backend::Docker,
            address: "10.13.13.6/24".into(),
            link: "zakuro-wg".into(),
            peers: vec![],
            host_routable: false,
            proxy: Some(proxy_addr.to_string()),
        })
        .unwrap();
        let agent = mesh_agent(std::time::Duration::from_secs(3));
        let body = agent
            .get("http://10.13.13.9:9000/health")
            .call()
            .unwrap()
            .into_body()
            .read_to_string()
            .unwrap();
        assert_eq!(body, "ok");
        std::env::remove_var("ZAKURO_STATE_DIR");
        let _ = std::fs::remove_dir_all(&dir);
    }

    #[test]
    fn conf_renders_wg_quick_from_profile_file() {
        let dir = std::env::temp_dir().join(format!("zc-vpn-conf-{}", std::process::id()));
        std::fs::create_dir_all(&dir).unwrap();
        let path = dir.join("wg.json");
        std::fs::write(&path, SAMPLE_PROFILE).unwrap();
        // file hatch requires the explicit opt-in (see profile::fetch_wg_profile)
        std::env::set_var("ZAKURO_ALLOW_FILE_PROFILE", "1");
        std::env::set_var("ZAKURO_WG_PROFILE_FILE", &path);

        let conf = super::conf().expect("conf renders");
        assert!(conf.contains("[Interface]"));
        assert!(conf.contains("Address = 10.13.13.6/24"));
        assert!(conf.contains("[Peer]"));
        assert!(conf.contains("Endpoint = 144.202.121.242:51822"));

        std::env::remove_var("ZAKURO_ALLOW_FILE_PROFILE");
        std::env::remove_var("ZAKURO_WG_PROFILE_FILE");
        let _ = std::fs::remove_dir_all(&dir);
    }
}