hashtree_cli/

p2p_common.rs

use std::path::PathBuf;
use std::sync::Arc;

use crate::config::Config;
use crate::socialgraph;
use crate::webrtc::{
    BluetoothConfig, KnownPeerSnapshot, MulticastConfig, PeerClassifier, PeerPool, WebRTCConfig,
    WebRTCState, WifiAwareConfig,
};
use anyhow::{Context, Result};
use hashtree_network::PeerMetadataSnapshot;

const PEER_STATE_FILE: &str = "mesh-peer-state.json";
const PEER_STATE_VERSION: u32 = 1;

#[derive(Debug, serde::Serialize, serde::Deserialize)]
struct PersistedPeerState {
    version: u32,
    #[serde(default)]
    peer_metadata: PeerMetadataSnapshot,
    #[serde(default)]
    known_peers: KnownPeerSnapshot,
}

impl Default for PersistedPeerState {
    fn default() -> Self {
        Self {
            version: PEER_STATE_VERSION,
            peer_metadata: PeerMetadataSnapshot::default(),
            known_peers: KnownPeerSnapshot::default(),
        }
    }
}

fn relay_is_loopback(relay: &str) -> bool {
    relay.contains("://127.0.0.1") || relay.contains("://localhost") || relay.contains("://[::1]")
}

fn bind_address_is_loopback(host: &str) -> bool {
    matches!(host, "127.0.0.1" | "localhost" | "::1" | "[::1]")
}

pub fn infer_loopback_peer_signal_url(bind_address: &str) -> Option<String> {
    let trimmed = bind_address.trim();
    let (host, port) = trimmed.rsplit_once(':')?;
    if port.is_empty() || !port.chars().all(|ch| ch.is_ascii_digit()) {
        return None;
    }
    let host = host.trim_start_matches('[').trim_end_matches(']');
    if !bind_address_is_loopback(host) {
        return None;
    }
    Some(format!("http://127.0.0.1:{port}"))
}

fn peer_state_path(data_dir: &std::path::Path) -> PathBuf {
    data_dir.join(PEER_STATE_FILE)
}

pub async fn load_peer_state(data_dir: &std::path::Path, state: &Arc<WebRTCState>) -> Result<bool> {
    let path = peer_state_path(data_dir);
    let content = match std::fs::read_to_string(&path) {
        Ok(content) => content,
        Err(err) if err.kind() == std::io::ErrorKind::NotFound => return Ok(false),
        Err(err) => return Err(err).with_context(|| format!("read {}", path.display())),
    };
    let persisted: PersistedPeerState = serde_json::from_str(&content)
        .with_context(|| format!("parse persisted peer state {}", path.display()))?;
    if persisted.version != PEER_STATE_VERSION {
        return Ok(false);
    }
    state
        .import_peer_metadata_snapshot(&persisted.peer_metadata)
        .await;
    state
        .import_known_peer_snapshot(&persisted.known_peers)
        .await;
    Ok(true)
}

pub async fn persist_peer_state(
    data_dir: &std::path::Path,
    state: &Arc<WebRTCState>,
) -> Result<()> {
    std::fs::create_dir_all(data_dir)
        .with_context(|| format!("create data dir {}", data_dir.display()))?;
    let path = peer_state_path(data_dir);
    let tmp_path = path.with_extension("json.tmp");
    let persisted = PersistedPeerState {
        version: PEER_STATE_VERSION,
        peer_metadata: state.peer_metadata_snapshot().await,
        known_peers: state.known_peer_snapshot().await,
    };
    let content = serde_json::to_vec_pretty(&persisted).context("encode persisted peer state")?;
    std::fs::write(&tmp_path, content).with_context(|| format!("write {}", tmp_path.display()))?;
    std::fs::rename(&tmp_path, &path)
        .with_context(|| format!("replace persisted peer state {}", path.display()))?;
    Ok(())
}

pub fn spawn_peer_state_persist_task(
    data_dir: PathBuf,
    state: Arc<WebRTCState>,
) -> tokio::task::JoinHandle<()> {
    tokio::spawn(async move {
        let mut interval = tokio::time::interval(std::time::Duration::from_secs(5));
        loop {
            interval.tick().await;
            if let Err(err) = persist_peer_state(&data_dir, &state).await {
                tracing::debug!("Failed to persist mesh peer state: {err:#}");
            }
        }
    })
}

pub fn peer_router_enabled(config: &Config) -> bool {
    config.server.enable_webrtc
        || (config.server.enable_multicast && config.server.max_multicast_peers > 0)
        || (config.server.enable_wifi_aware && config.server.max_wifi_aware_peers > 0)
        || (config.server.enable_bluetooth && config.server.max_bluetooth_peers > 0)
}

pub fn should_start_stun_server(config: &Config) -> bool {
    config.server.enable_webrtc && config.server.stun_port > 0
}

/// Build default WebRTC config from daemon/app config.
pub fn default_webrtc_config(config: &Config) -> WebRTCConfig {
    let active_relays = config.nostr.active_relays();
    let local_only_relays =
        !active_relays.is_empty() && active_relays.iter().all(|relay| relay_is_loopback(relay));
    let relays = if config.server.enable_webrtc {
        active_relays
    } else {
        Vec::new()
    };
    let stun_servers =
        if !config.server.enable_webrtc || (config.server.enable_multicast && local_only_relays) {
            Vec::new()
        } else {
            WebRTCConfig::default().stun_servers
        };
    let signal_urls = if config.server.peer_signal_urls.is_empty() {
        infer_loopback_peer_signal_url(&config.server.bind_address)
            .into_iter()
            .collect()
    } else {
        config
            .server
            .peer_signal_urls
            .iter()
            .map(|url| url.trim().trim_end_matches('/').to_string())
            .filter(|url| url.starts_with("http://"))
            .collect()
    };

    WebRTCConfig {
        relays,
        signaling_enabled: config.server.enable_webrtc,
        hash_get_enabled: config.server.mode.hash_get_enabled(),
        signal_urls,
        stun_servers,
        multicast: MulticastConfig {
            enabled: config.server.enable_multicast,
            group: config.server.multicast_group.clone(),
            port: config.server.multicast_port,
            max_peers: config.server.max_multicast_peers,
            ..Default::default()
        },
        wifi_aware: WifiAwareConfig {
            enabled: config.server.enable_wifi_aware,
            max_peers: config.server.max_wifi_aware_peers,
            ..Default::default()
        },
        bluetooth: BluetoothConfig {
            enabled: config.server.enable_bluetooth,
            max_peers: config.server.max_bluetooth_peers,
        },
        ..Default::default()
    }
}

/// Build peer classifier used by daemon/runtime startup paths.
pub fn build_peer_classifier(
    data_dir: PathBuf,
    store: Arc<dyn socialgraph::SocialGraphBackend>,
) -> PeerClassifier {
    let contacts_file = data_dir.join("contacts.json");
    Arc::new(move |pubkey_hex: &str| {
        if contacts_file.exists() {
            if let Ok(data) = std::fs::read_to_string(&contacts_file) {
                if let Ok(contacts) = serde_json::from_str::<Vec<String>>(&data) {
                    if contacts.contains(&pubkey_hex.to_string()) {
                        return PeerPool::Follows;
                    }
                }
            }
        }
        if let Ok(pk_bytes) = hex::decode(pubkey_hex) {
            if pk_bytes.len() == 32 {
                let pk: [u8; 32] = pk_bytes.try_into().unwrap();
                if let Some(dist) = socialgraph::get_follow_distance(store.as_ref(), &pk) {
                    if dist <= 2 {
                        return PeerPool::Follows;
                    }
                }
            }
        }
        PeerPool::Other
    })
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn default_webrtc_config_disables_stun_for_loopback_only_multicast() {
        let mut config = Config::default();
        config.server.enable_multicast = true;
        config.server.max_multicast_peers = 4;
        config.nostr.relays = vec!["ws://127.0.0.1:8080/ws".to_string()];

        let webrtc = default_webrtc_config(&config);
        assert!(webrtc.stun_servers.is_empty());
    }

    #[test]
    fn default_webrtc_config_keeps_stun_for_non_loopback_relays() {
        let mut config = Config::default();
        config.server.enable_multicast = true;
        config.server.max_multicast_peers = 4;
        config.nostr.relays = vec!["wss://relay.example".to_string()];

        let webrtc = default_webrtc_config(&config);
        assert!(!webrtc.stun_servers.is_empty());
    }

    #[test]
    fn default_webrtc_config_maps_bluetooth_limits() {
        let mut config = Config::default();
        config.server.enable_bluetooth = true;
        config.server.max_bluetooth_peers = 3;

        let webrtc = default_webrtc_config(&config);
        assert!(webrtc.signaling_enabled);
        assert!(webrtc.bluetooth.enabled);
        assert_eq!(webrtc.bluetooth.max_peers, 3);
    }

    #[test]
    fn default_webrtc_config_maps_wifi_aware_limits() {
        let mut config = Config::default();
        config.server.enable_wifi_aware = true;
        config.server.max_wifi_aware_peers = 4;

        let webrtc = default_webrtc_config(&config);
        assert!(webrtc.signaling_enabled);
        assert!(webrtc.wifi_aware.enabled);
        assert_eq!(webrtc.wifi_aware.max_peers, 4);
    }

    #[test]
    fn default_webrtc_config_uses_loopback_bind_address_for_webrtc_signaling() {
        let mut config = Config::default();
        config.server.bind_address = "127.0.0.1:18080".to_string();

        let webrtc = default_webrtc_config(&config);
        assert_eq!(
            webrtc.signal_urls,
            vec!["http://127.0.0.1:18080".to_string()]
        );
    }

    #[test]
    fn default_webrtc_config_prefers_explicit_peer_signal_urls() {
        let mut config = Config::default();
        config.server.bind_address = "127.0.0.1:18080".to_string();
        config.server.peer_signal_urls = vec![
            "http://peer.example:18080/".to_string(),
            "https://peer.example/".to_string(),
        ];

        let webrtc = default_webrtc_config(&config);
        assert_eq!(
            webrtc.signal_urls,
            vec!["http://peer.example:18080".to_string()]
        );
    }

    #[test]
    fn default_webrtc_config_strips_relays_and_stun_when_webrtc_disabled() {
        let mut config = Config::default();
        config.server.enable_webrtc = false;
        config.server.enable_bluetooth = true;
        config.server.max_bluetooth_peers = 2;
        config.server.stun_port = 3478;
        config.nostr.relays = vec!["wss://relay.example".to_string()];

        let webrtc = default_webrtc_config(&config);
        assert!(!webrtc.signaling_enabled);
        assert!(webrtc.relays.is_empty());
        assert!(webrtc.stun_servers.is_empty());
    }

    #[test]
    fn stun_server_only_starts_when_webrtc_is_enabled() {
        let mut config = Config::default();
        config.server.stun_port = 3478;

        assert!(should_start_stun_server(&config));

        config.server.enable_webrtc = false;
        assert!(!should_start_stun_server(&config));
    }

    #[test]
    fn peer_router_enabled_for_wifi_aware_only() {
        let mut config = Config::default();
        config.server.enable_webrtc = false;
        config.server.enable_multicast = false;
        config.server.max_multicast_peers = 0;
        config.server.enable_bluetooth = false;
        config.server.max_bluetooth_peers = 0;
        config.server.enable_wifi_aware = true;
        config.server.max_wifi_aware_peers = 2;

        assert!(peer_router_enabled(&config));

        config.server.max_wifi_aware_peers = 0;
        assert!(!peer_router_enabled(&config));
    }
}