dragoon-server 0.1.0

//! SQLite schema, bootstrap, and forward migrations.
//!
//! Mirrors `python/src/remote_executor/server/db.py`. The schema text is
//! identical so a Python-managed database is readable by the Rust server
//! and vice versa — supporting the rolling Python ↔ Rust migration the
//! plan calls for.

use std::path::Path;

use anyhow::{Context, Result};
use rusqlite::Connection;

pub const SCHEMA_VERSION: i64 = 3;

const SCHEMA_SQL: &str = r"
CREATE TABLE IF NOT EXISTS schema_version (
    version INTEGER PRIMARY KEY
);

CREATE TABLE IF NOT EXISTS users (
    id                INTEGER PRIMARY KEY AUTOINCREMENT,
    username          TEXT NOT NULL UNIQUE,
    password_hash     TEXT NOT NULL,
    totp_secret_enc   TEXT NOT NULL,
    recovery_codes_hash TEXT,
    created_at        TEXT NOT NULL,
    revoked_at        TEXT
);

CREATE TABLE IF NOT EXISTS user_pubkeys (
    id           INTEGER PRIMARY KEY AUTOINCREMENT,
    user_id      INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    fingerprint  TEXT NOT NULL,
    alg          TEXT NOT NULL,
    pubkey_blob  BLOB NOT NULL,
    label        TEXT,
    added_at     TEXT NOT NULL,
    revoked_at   TEXT
);
CREATE UNIQUE INDEX IF NOT EXISTS idx_user_pubkeys_fp
    ON user_pubkeys(user_id, fingerprint);

CREATE TABLE IF NOT EXISTS sessions (
    token_hash   TEXT PRIMARY KEY,
    user_id      INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    fingerprint  TEXT NOT NULL,
    created_at   TEXT NOT NULL,
    expires_at   TEXT NOT NULL,
    revoked_at   TEXT
);
CREATE INDEX IF NOT EXISTS idx_sessions_user ON sessions(user_id);

CREATE TABLE IF NOT EXISTS nonces (
    user_id     INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    nonce       TEXT NOT NULL,
    expires_at  TEXT NOT NULL,
    PRIMARY KEY (user_id, nonce)
);
CREATE INDEX IF NOT EXISTS idx_nonces_exp ON nonces(expires_at);

CREATE TABLE IF NOT EXISTS challenges (
    challenge   TEXT PRIMARY KEY,
    expires_at  TEXT NOT NULL,
    used_at     TEXT
);
CREATE INDEX IF NOT EXISTS idx_challenges_exp ON challenges(expires_at);

CREATE TABLE IF NOT EXISTS workers (
    id                       INTEGER PRIMARY KEY AUTOINCREMENT,
    name                     TEXT NOT NULL UNIQUE,
    token_hash               TEXT,
    register_code_hash       TEXT,
    register_code_expires    TEXT,
    last_poll_at             TEXT,
    current_pwd              TEXT,
    current_task_id          TEXT,
    status                   TEXT,
    created_at               TEXT NOT NULL,
    revoked_at               TEXT,
    client_pubkey            BLOB
);

CREATE TABLE IF NOT EXISTS server_signing_key (
    id           INTEGER PRIMARY KEY CHECK (id = 1),
    priv_pem     BLOB NOT NULL,
    pub_blob     BLOB NOT NULL,
    fingerprint  TEXT NOT NULL,
    created_at   TEXT NOT NULL
);

CREATE TABLE IF NOT EXISTS tasks (
    task_id          TEXT PRIMARY KEY,
    worker_name      TEXT NOT NULL,
    submitter        TEXT NOT NULL,
    kind             TEXT NOT NULL,
    payload          TEXT NOT NULL,
    collect_json     TEXT NOT NULL,
    limits_json      TEXT NOT NULL,
    state            TEXT NOT NULL,
    submitted_at     TEXT NOT NULL,
    started_at       TEXT,
    finished_at      TEXT,
    exit_code        INTEGER,
    final_pwd        TEXT,
    error            TEXT,
    fetch_path       TEXT,
    purged           INTEGER NOT NULL DEFAULT 0,
    last_access_at   TEXT,
    cancel_requested INTEGER NOT NULL DEFAULT 0,
    worker_seq       INTEGER NOT NULL DEFAULT 0
);
CREATE INDEX IF NOT EXISTS idx_tasks_worker_state ON tasks(worker_name, state);
CREATE INDEX IF NOT EXISTS idx_tasks_submitted_at ON tasks(submitted_at);
CREATE INDEX IF NOT EXISTS idx_tasks_worker_seq ON tasks(worker_name, worker_seq);

CREATE TABLE IF NOT EXISTS controller_messages (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    user_id       INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    kind          TEXT NOT NULL,
    task_id       TEXT,
    worker_name   TEXT,
    error         TEXT,
    payload_json  TEXT NOT NULL,
    created_at    TEXT NOT NULL,
    read_at       TEXT
);
CREATE INDEX IF NOT EXISTS idx_msgs_user ON controller_messages(user_id, id);
CREATE INDEX IF NOT EXISTS idx_msgs_unread
    ON controller_messages(user_id, read_at) WHERE read_at IS NULL;

CREATE TABLE IF NOT EXISTS artifacts (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    task_id     TEXT NOT NULL REFERENCES tasks(task_id) ON DELETE CASCADE,
    path        TEXT NOT NULL,
    size        INTEGER NOT NULL,
    sha256      TEXT NOT NULL,
    blob_path   TEXT NOT NULL
);
CREATE INDEX IF NOT EXISTS idx_artifacts_task ON artifacts(task_id);

CREATE TABLE IF NOT EXISTS audit_log (
    id              INTEGER PRIMARY KEY AUTOINCREMENT,
    ts              TEXT NOT NULL,
    actor           TEXT,
    action          TEXT NOT NULL,
    target          TEXT,
    key_fingerprint TEXT,
    metadata_json   TEXT
);
CREATE INDEX IF NOT EXISTS idx_audit_ts ON audit_log(ts);
";

/// Open a SQLite connection at `path`, set WAL + foreign-keys + relaxed
/// fsync (matching the Python `connect()`), and return it. Schema is NOT
/// applied — call [`bootstrap`] afterwards.
pub fn connect(path: impl AsRef<Path>) -> Result<Connection> {
    let conn = Connection::open(path.as_ref())
        .with_context(|| format!("opening sqlite at {}", path.as_ref().display()))?;
    conn.pragma_update(None, "journal_mode", "WAL")?;
    conn.pragma_update(None, "foreign_keys", "ON")?;
    conn.pragma_update(None, "synchronous", "NORMAL")?;
    Ok(conn)
}

/// Open an in-memory SQLite for tests.
pub fn connect_in_memory() -> Result<Connection> {
    let conn = Connection::open_in_memory()?;
    conn.pragma_update(None, "foreign_keys", "ON")?;
    Ok(conn)
}

/// Apply the schema (CREATE TABLE/INDEX IF NOT EXISTS) and run forward
/// migrations from older versions. Idempotent on a v3 database.
///
/// Order matters: when an older schema is detected we run the column
/// additions FIRST so that the v3 SCHEMA_SQL — which references the new
/// columns in `CREATE INDEX` statements — can be applied as a no-op
/// idempotent layer afterwards.
pub fn bootstrap(conn: &Connection) -> Result<()> {
    // Always make sure the version table exists so we can read the cursor
    // before deciding what else to apply.
    conn.execute_batch(
        "CREATE TABLE IF NOT EXISTS schema_version (version INTEGER PRIMARY KEY)",
    )?;
    let mut current: i64 = conn
        .query_row("SELECT version FROM schema_version", [], |r| r.get(0))
        .unwrap_or(0);

    // Forward migrations: bring an existing pre-v3 database up to v3 BEFORE
    // we apply SCHEMA_SQL. The migrations themselves are pure ALTER TABLE.
    if current == 1 {
        let has_client_pubkey: bool = conn
            .prepare("PRAGMA table_info(workers)")?
            .query_map([], |r| r.get::<_, String>(1))?
            .filter_map(Result::ok)
            .any(|c| c == "client_pubkey");
        if !has_client_pubkey {
            conn.execute("ALTER TABLE workers ADD COLUMN client_pubkey BLOB", [])?;
        }
        current = 2;
    }
    if current == 2 {
        let has_worker_seq: bool = conn
            .prepare("PRAGMA table_info(tasks)")?
            .query_map([], |r| r.get::<_, String>(1))?
            .filter_map(Result::ok)
            .any(|c| c == "worker_seq");
        if !has_worker_seq {
            conn.execute(
                "ALTER TABLE tasks ADD COLUMN worker_seq INTEGER NOT NULL DEFAULT 0",
                [],
            )?;
        }
        current = 3;
    }

    // Now apply the v3 schema. CREATE TABLE IF NOT EXISTS is a no-op on
    // existing tables; CREATE INDEX IF NOT EXISTS references columns that
    // now exist either because the migrations above added them or because
    // the table was just freshly created.
    conn.execute_batch(SCHEMA_SQL)?;

    let stamped: Option<i64> = conn
        .query_row("SELECT version FROM schema_version", [], |r| r.get(0))
        .ok();
    if stamped.is_none() {
        conn.execute(
            "INSERT INTO schema_version (version) VALUES (?)",
            [SCHEMA_VERSION],
        )?;
    } else {
        conn.execute("UPDATE schema_version SET version=?", [SCHEMA_VERSION])?;
    }

    if current != SCHEMA_VERSION && current != 0 {
        anyhow::bail!("unsupported schema version {current}");
    }
    Ok(())
}

/// Read the schema_version row (returns 0 if unset).
pub fn schema_version(conn: &Connection) -> Result<i64> {
    Ok(conn
        .query_row("SELECT version FROM schema_version", [], |r| r.get(0))
        .unwrap_or(0))
}

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

    fn fresh() -> Connection {
        let c = connect_in_memory().unwrap();
        bootstrap(&c).unwrap();
        c
    }

    fn table_names(conn: &Connection) -> Vec<String> {
        conn.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%' ORDER BY name")
            .unwrap()
            .query_map([], |r| r.get::<_, String>(0))
            .unwrap()
            .filter_map(Result::ok)
            .collect()
    }

    #[test]
    fn fresh_bootstrap_creates_all_tables() {
        let c = fresh();
        let tables: std::collections::HashSet<String> = table_names(&c).into_iter().collect();
        for required in &[
            "schema_version",
            "users",
            "user_pubkeys",
            "sessions",
            "nonces",
            "challenges",
            "workers",
            "tasks",
            "artifacts",
            "audit_log",
            "server_signing_key",
            "controller_messages",
        ] {
            assert!(
                tables.contains(*required),
                "expected table {required} after bootstrap"
            );
        }
    }

    #[test]
    fn bootstrap_is_idempotent() {
        let c = fresh();
        bootstrap(&c).unwrap();
        bootstrap(&c).unwrap();
        assert_eq!(schema_version(&c).unwrap(), SCHEMA_VERSION);
    }

    #[test]
    fn schema_version_after_fresh_bootstrap_is_three() {
        let c = fresh();
        assert_eq!(schema_version(&c).unwrap(), 3);
    }

    #[test]
    fn migration_v1_to_v3_adds_columns_and_tables() {
        // Build a minimal v1 schema: no client_pubkey on workers, no
        // worker_seq on tasks, no controller_messages, no server_signing_key.
        let c = connect_in_memory().unwrap();
        c.execute_batch(
            "
            CREATE TABLE schema_version (version INTEGER PRIMARY KEY);
            CREATE TABLE users (id INTEGER PRIMARY KEY, username TEXT NOT NULL UNIQUE,
                password_hash TEXT NOT NULL, totp_secret_enc TEXT NOT NULL, created_at TEXT NOT NULL);
            CREATE TABLE workers (id INTEGER PRIMARY KEY, name TEXT NOT NULL UNIQUE,
                token_hash TEXT, created_at TEXT NOT NULL);
            CREATE TABLE tasks (task_id TEXT PRIMARY KEY, worker_name TEXT NOT NULL,
                submitter TEXT NOT NULL, kind TEXT NOT NULL, payload TEXT NOT NULL,
                collect_json TEXT NOT NULL, limits_json TEXT NOT NULL, state TEXT NOT NULL,
                submitted_at TEXT NOT NULL,
                purged INTEGER NOT NULL DEFAULT 0,
                cancel_requested INTEGER NOT NULL DEFAULT 0);
            INSERT INTO schema_version (version) VALUES (1);
            ",
        )
        .unwrap();

        bootstrap(&c).unwrap();

        // workers.client_pubkey must now exist
        let cols: Vec<String> = c
            .prepare("PRAGMA table_info(workers)")
            .unwrap()
            .query_map([], |r| r.get::<_, String>(1))
            .unwrap()
            .filter_map(Result::ok)
            .collect();
        assert!(cols.contains(&"client_pubkey".to_string()));

        // tasks.worker_seq must now exist
        let cols: Vec<String> = c
            .prepare("PRAGMA table_info(tasks)")
            .unwrap()
            .query_map([], |r| r.get::<_, String>(1))
            .unwrap()
            .filter_map(Result::ok)
            .collect();
        assert!(cols.contains(&"worker_seq".to_string()));

        // controller_messages + server_signing_key created
        let tables: std::collections::HashSet<_> = table_names(&c).into_iter().collect();
        assert!(tables.contains("controller_messages"));
        assert!(tables.contains("server_signing_key"));

        assert_eq!(schema_version(&c).unwrap(), 3);
    }

    #[test]
    fn foreign_key_cascade_users_to_pubkeys() {
        let c = fresh();
        c.execute(
            "INSERT INTO users (username, password_hash, totp_secret_enc, created_at)
             VALUES (?, ?, ?, ?)",
            rusqlite::params!["alice", "h", "s", "2026-01-01T00:00:00Z"],
        )
        .unwrap();
        let uid: i64 = c.last_insert_rowid();
        c.execute(
            "INSERT INTO user_pubkeys (user_id, fingerprint, alg, pubkey_blob, added_at)
             VALUES (?, ?, ?, ?, ?)",
            rusqlite::params![uid, "SHA256:fp", "ssh-ed25519", &b"k"[..], "2026-01-01T00:00:00Z"],
        )
        .unwrap();
        c.execute("DELETE FROM users WHERE id=?", [uid]).unwrap();
        let n: i64 = c
            .query_row("SELECT COUNT(*) FROM user_pubkeys", [], |r| r.get(0))
            .unwrap();
        assert_eq!(n, 0, "deleting a user must cascade-delete their pubkeys");
    }

    #[test]
    fn workers_unique_name_constraint() {
        let c = fresh();
        c.execute(
            "INSERT INTO workers (name, created_at) VALUES (?, ?)",
            rusqlite::params!["w1", "2026-01-01T00:00:00Z"],
        )
        .unwrap();
        let dup = c.execute(
            "INSERT INTO workers (name, created_at) VALUES (?, ?)",
            rusqlite::params!["w1", "2026-01-01T00:00:00Z"],
        );
        assert!(dup.is_err(), "duplicate worker name must violate UNIQUE");
    }

    #[test]
    fn nonces_pk_user_nonce() {
        let c = fresh();
        c.execute(
            "INSERT INTO users (username, password_hash, totp_secret_enc, created_at)
             VALUES (?, ?, ?, ?)",
            rusqlite::params!["alice", "h", "s", "2026-01-01T00:00:00Z"],
        )
        .unwrap();
        let uid: i64 = c.last_insert_rowid();
        c.execute(
            "INSERT INTO nonces (user_id, nonce, expires_at) VALUES (?,?,?)",
            rusqlite::params![uid, "abc", "2026-01-01T00:00:00Z"],
        )
        .unwrap();
        let dup = c.execute(
            "INSERT INTO nonces (user_id, nonce, expires_at) VALUES (?,?,?)",
            rusqlite::params![uid, "abc", "2026-01-01T00:00:00Z"],
        );
        assert!(dup.is_err(), "(user_id,nonce) replay must be rejected");
    }
}