v2.rs

use std::sync::Arc;

use payjoin::persist::SessionPersister;
use payjoin::receive::v2::SessionEvent as ReceiverSessionEvent;
use payjoin::send::v2::SessionEvent as SenderSessionEvent;
use payjoin::HpkePublicKey;
use rusqlite::params;

use super::*;

#[derive(Debug, Clone)]
pub(crate) struct SessionId(i64);

impl core::ops::Deref for SessionId {
    type Target = i64;
    fn deref(&self) -> &Self::Target { &self.0 }
}

impl std::fmt::Display for SessionId {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { write!(f, "{}", self.0) }
}

#[derive(Clone, Debug)]
pub(crate) struct SenderPersister {
    db: Arc<Database>,
    session_id: SessionId,
}

impl SenderPersister {
    pub fn new(
        db: Arc<Database>,
        pj_uri: &str,
        receiver_pubkey: &HpkePublicKey,
    ) -> crate::db::Result<Self> {
        let conn = db.get_connection()?;
        let receiver_pubkey_bytes = receiver_pubkey.to_compressed_bytes();

        let (duplicate_uri, duplicate_rk): (bool, bool) = conn.query_row(
            "SELECT \
                EXISTS(SELECT 1 FROM send_sessions WHERE pj_uri = ?1), \
                EXISTS(SELECT 1 FROM send_sessions WHERE receiver_pubkey = ?2)",
            params![pj_uri, &receiver_pubkey_bytes],
            |row| Ok((row.get(0)?, row.get(1)?)),
        )?;

        if duplicate_uri {
            return Err(Error::DuplicateSendSession(DuplicateKind::Uri));
        }
        if duplicate_rk {
            return Err(Error::DuplicateSendSession(DuplicateKind::ReceiverPubkey));
        }

        // Create a new session in send_sessions and get its ID
        let session_id: i64 = conn.query_row(
            "INSERT INTO send_sessions (pj_uri, receiver_pubkey) VALUES (?1, ?2) RETURNING session_id",
            params![pj_uri, &receiver_pubkey_bytes],
            |row| row.get(0),
        )?;

        Ok(Self { db, session_id: SessionId(session_id) })
    }

    pub fn from_id(db: Arc<Database>, id: SessionId) -> Self { Self { db, session_id: id } }
}
impl SessionPersister for SenderPersister {
    type SessionEvent = SenderSessionEvent;
    type InternalStorageError = crate::db::error::Error;

    fn save_event(
        &self,
        event: SenderSessionEvent,
    ) -> std::result::Result<(), Self::InternalStorageError> {
        let conn = self.db.get_connection()?;
        let event_data = serde_json::to_string(&event).map_err(Error::Serialize)?;

        conn.execute(
            "INSERT INTO send_session_events (session_id, event_data, created_at) VALUES (?1, ?2, ?3)",
            params![*self.session_id, event_data, now()],
        )?;

        Ok(())
    }

    fn load(
        &self,
    ) -> std::result::Result<Box<dyn Iterator<Item = SenderSessionEvent>>, Self::InternalStorageError>
    {
        let conn = self.db.get_connection()?;
        let mut stmt = conn.prepare(
            "SELECT event_data FROM send_session_events WHERE session_id = ?1 ORDER BY id ASC",
        )?;

        let event_rows = stmt.query_map(params![*self.session_id], |row| {
            let event_data: String = row.get(0)?;
            Ok(event_data)
        })?;

        let events: Vec<SenderSessionEvent> = event_rows
            .map(|row| {
                let event_data = row.expect("Failed to read event data from database");
                serde_json::from_str::<SenderSessionEvent>(&event_data)
                    .expect("Database corruption: failed to deserialize session event")
            })
            .collect();

        Ok(Box::new(events.into_iter()))
    }

    fn close(&self) -> std::result::Result<(), Self::InternalStorageError> {
        let conn = self.db.get_connection()?;

        conn.execute(
            "UPDATE send_sessions SET completed_at = ?1 WHERE session_id = ?2",
            params![now(), *self.session_id],
        )?;

        Ok(())
    }
}

#[derive(Clone)]
pub(crate) struct ReceiverPersister {
    db: Arc<Database>,
    session_id: SessionId,
}

impl ReceiverPersister {
    pub fn new(db: Arc<Database>) -> crate::db::Result<Self> {
        let conn = db.get_connection()?;

        // Create a new session in receive_sessions and get its ID
        let session_id: i64 = conn.query_row(
            "INSERT INTO receive_sessions (session_id) VALUES (NULL) RETURNING session_id",
            [],
            |row| row.get(0),
        )?;

        Ok(Self { db, session_id: SessionId(session_id) })
    }

    pub fn from_id(db: Arc<Database>, id: SessionId) -> Self { Self { db, session_id: id } }
}

impl SessionPersister for ReceiverPersister {
    type SessionEvent = ReceiverSessionEvent;
    type InternalStorageError = crate::db::error::Error;

    fn save_event(
        &self,
        event: ReceiverSessionEvent,
    ) -> std::result::Result<(), Self::InternalStorageError> {
        let conn = self.db.get_connection()?;
        let event_data = serde_json::to_string(&event).map_err(Error::Serialize)?;

        conn.execute(
            "INSERT INTO receive_session_events (session_id, event_data, created_at) VALUES (?1, ?2, ?3)",
            params![*self.session_id, event_data, now()],
        )?;

        Ok(())
    }

    fn load(
        &self,
    ) -> std::result::Result<
        Box<dyn Iterator<Item = ReceiverSessionEvent>>,
        Self::InternalStorageError,
    > {
        let conn = self.db.get_connection()?;
        let mut stmt = conn.prepare(
            "SELECT event_data FROM receive_session_events WHERE session_id = ?1 ORDER BY id ASC",
        )?;

        let event_rows = stmt.query_map(params![*self.session_id], |row| {
            let event_data: String = row.get(0)?;
            Ok(event_data)
        })?;

        let events: Vec<ReceiverSessionEvent> = event_rows
            .map(|row| {
                let event_data = row.expect("Failed to read event data from database");
                serde_json::from_str::<ReceiverSessionEvent>(&event_data)
                    .expect("Database corruption: failed to deserialize session event")
            })
            .collect();

        Ok(Box::new(events.into_iter()))
    }

    fn close(&self) -> std::result::Result<(), Self::InternalStorageError> {
        let conn = self.db.get_connection()?;

        conn.execute(
            "UPDATE receive_sessions SET completed_at = ?1 WHERE session_id = ?2",
            params![now(), *self.session_id],
        )?;

        Ok(())
    }
}

impl Database {
    pub(crate) fn get_recv_session_ids(&self) -> Result<Vec<SessionId>> {
        let conn = self.get_connection()?;
        let mut stmt =
            conn.prepare("SELECT session_id FROM receive_sessions WHERE completed_at IS NULL")?;

        let session_rows = stmt.query_map([], |row| {
            let session_id: i64 = row.get(0)?;
            Ok(SessionId(session_id))
        })?;

        let mut session_ids = Vec::new();
        for session_row in session_rows {
            let session_id = session_row?;
            session_ids.push(session_id);
        }

        Ok(session_ids)
    }

    pub(crate) fn get_send_session_ids(&self) -> Result<Vec<SessionId>> {
        let conn = self.get_connection()?;
        let mut stmt =
            conn.prepare("SELECT session_id FROM send_sessions WHERE completed_at IS NULL")?;

        let session_rows = stmt.query_map([], |row| {
            let session_id: i64 = row.get(0)?;
            Ok(SessionId(session_id))
        })?;

        let mut session_ids = Vec::new();
        for session_row in session_rows {
            let session_id = session_row?;
            session_ids.push(session_id);
        }

        Ok(session_ids)
    }

    pub(crate) fn get_send_session_receiver_pk(
        &self,
        session_id: &SessionId,
    ) -> Result<HpkePublicKey> {
        let conn = self.get_connection()?;
        let mut stmt =
            conn.prepare("SELECT receiver_pubkey FROM send_sessions WHERE session_id = ?1")?;
        let receiver_pubkey: Vec<u8> = stmt.query_row(params![session_id.0], |row| row.get(0))?;
        Ok(HpkePublicKey::from_compressed_bytes(&receiver_pubkey).expect("Valid receiver pubkey"))
    }

    pub(crate) fn get_inactive_send_session_ids(&self) -> Result<Vec<(SessionId, u64)>> {
        let conn = self.get_connection()?;
        let mut stmt = conn.prepare(
            "SELECT session_id, completed_at FROM send_sessions WHERE completed_at IS NOT NULL",
        )?;
        let session_rows = stmt.query_map([], |row| {
            let session_id: i64 = row.get(0)?;
            let completed_at: u64 = row.get(1)?;
            Ok((SessionId(session_id), completed_at))
        })?;

        let mut session_ids = Vec::new();
        for session_row in session_rows {
            let (session_id, completed_at) = session_row?;
            session_ids.push((session_id, completed_at));
        }
        Ok(session_ids)
    }

    pub(crate) fn get_inactive_recv_session_ids(&self) -> Result<Vec<(SessionId, u64)>> {
        let conn = self.get_connection()?;
        let mut stmt = conn.prepare(
            "SELECT session_id, completed_at FROM receive_sessions WHERE completed_at IS NOT NULL",
        )?;
        let session_rows = stmt.query_map([], |row| {
            let session_id: i64 = row.get(0)?;
            let completed_at: u64 = row.get(1)?;
            Ok((SessionId(session_id), completed_at))
        })?;

        let mut session_ids = Vec::new();
        for session_row in session_rows {
            let (session_id, completed_at) = session_row?;
            session_ids.push((session_id, completed_at));
        }
        Ok(session_ids)
    }
}

#[cfg(all(test, feature = "v2"))]
mod tests {
    use std::sync::Arc;

    use payjoin::HpkeKeyPair;

    use super::*;

    fn create_test_db() -> Arc<Database> {
        // Use an in-memory database for tests
        let manager = r2d2_sqlite::SqliteConnectionManager::memory()
            .with_init(|conn| conn.execute_batch("PRAGMA locking_mode = EXCLUSIVE;"));
        let pool = r2d2::Pool::new(manager).expect("pool creation should succeed");
        let conn = pool.get().expect("connection should succeed");
        Database::init_schema(&conn).expect("schema init should succeed");
        Arc::new(Database(pool))
    }

    fn make_receiver_pubkey() -> payjoin::HpkePublicKey { HpkeKeyPair::gen_keypair().1 }

    // Second call with the same URI (same active session) should return DuplicateSendSession(Uri).
    #[test]
    fn test_duplicate_uri_returns_error() {
        let db = create_test_db();
        let rk1 = make_receiver_pubkey();
        let rk2 = make_receiver_pubkey();
        let uri = "bitcoin:addr1?pj=https://example.com/BBBBBBBB";

        SenderPersister::new(db.clone(), uri, &rk1).expect("first session should succeed");

        let err = SenderPersister::new(db, uri, &rk2).expect_err("duplicate URI should fail");
        assert!(
            matches!(err, Error::DuplicateSendSession(DuplicateKind::Uri)),
            "expected DuplicateSendSession(Uri), got: {err:?}"
        );
    }

    // Same receiver pubkey under a different URI should return DuplicateSendSession(ReceiverPubkey).
    #[test]
    fn test_duplicate_rk_returns_error() {
        let db = create_test_db();
        let rk = make_receiver_pubkey();
        let uri1 = "bitcoin:addr1?pj=https://example.com/CCCCCCCC";
        let uri2 = "bitcoin:addr1?pj=https://example.com/DDDDDDDD";

        SenderPersister::new(db.clone(), uri1, &rk).expect("first session should succeed");

        let err = SenderPersister::new(db, uri2, &rk).expect_err("duplicate RK should fail");
        assert!(
            matches!(err, Error::DuplicateSendSession(DuplicateKind::ReceiverPubkey)),
            "expected DuplicateSendSession(ReceiverPubkey), got: {err:?}"
        );
    }

    // After a session is marked completed, a new session with the same URI must still be rejected
    // to prevent address reuse, HPKE receiver-key reuse
    #[test]
    fn test_completed_session_blocks_reuse() {
        let db = create_test_db();
        let rk1 = make_receiver_pubkey();
        let rk2 = make_receiver_pubkey();
        let uri = "bitcoin:addr1?pj=https://example.com/EEEEEEEE";

        let persister =
            SenderPersister::new(db.clone(), uri, &rk1).expect("first session should succeed");

        // Mark the session as completed
        use payjoin::persist::SessionPersister;
        persister.close().expect("close should succeed");

        // A new session with the same URI must be rejected even after completion
        let err = SenderPersister::new(db, uri, &rk2)
            .expect_err("reuse of a completed session URI must be rejected");
        assert!(
            matches!(err, Error::DuplicateSendSession(DuplicateKind::Uri)),
            "expected DuplicateSendSession(Uri), got: {err:?}"
        );
    }
}