knox/internal/db/gossip.go

package db

import (
	"database/sql"
	"fmt"
)

// GossipObservation is the serializable wire form of an observation exchanged
// between nodes. It carries the locator (NodeID, HCL) so the receiver can
// idempotently INSERT OR IGNORE on the unique index.
type GossipObservation struct {
	NodeID          string
	HCL             int64
	Fingerprint     string
	SourceID        string
	SourcePath      string
	Project         string
	ContentType     string
	Title           string
	Summary         string
	CollectedAt     string
	CreatedAt       string
	LineStart       int
	LineEnd         int
	Confidence      float64
	IngesterVersion string
	Trigger         string
	Provenance      string
}

// PushObservations inserts gossip rows idempotently. Rows whose (node_id, hcl)
// already exist are ignored (a node's HCL is locally monotonic, so a given
// locator is immutable). Returns the number newly inserted.
func (k *KnoxDB) PushObservations(rows []GossipObservation) (int, error) {
	tx, err := k.db.Begin()
	if err != nil {
		return 0, err
	}
	defer tx.Rollback()

	inserted := 0
	for _, o := range rows {
		res, err := tx.Exec(
			`INSERT OR IGNORE INTO observations
			 (fingerprint, source_id, source_path, project, content_type, title, summary,
			  collected_at, created_at, line_start, line_end, confidence, ingester_version, trigger, provenance,
			  node_id, hcl)
			 VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
			o.Fingerprint, o.SourceID, o.SourcePath, o.Project, o.ContentType, o.Title, o.Summary,
			o.CollectedAt, o.CreatedAt, o.LineStart, o.LineEnd, o.Confidence, o.IngesterVersion, o.Trigger, o.Provenance,
			o.NodeID, o.HCL,
		)
		if err != nil {
			return inserted, fmt.Errorf("push observation: %w", err)
		}
		if n, _ := res.RowsAffected(); n > 0 {
			inserted++
		}
	}
	return inserted, tx.Commit()
}

// ObservationsAfter returns gossip rows for one node after a given HCL cursor,
// in HCL order. after <= 0 means "everything" (initial handshake).
func (k *KnoxDB) ObservationsAfter(nodeID string, after int64, limit int) ([]GossipObservation, error) {
	if limit <= 0 {
		limit = 500
	}
	query := `SELECT node_id, hcl, fingerprint, source_id, COALESCE(source_path,''), COALESCE(project,''),
	                 COALESCE(content_type,''), COALESCE(title,''), COALESCE(summary,''),
	                 COALESCE(collected_at,''), COALESCE(created_at,''),
	                 COALESCE(line_start,0), COALESCE(line_end,0), COALESCE(confidence,0.5),
	                 COALESCE(ingester_version,''), COALESCE(trigger,''), COALESCE(provenance,'{}')
	          FROM observations WHERE node_id=?`
	args := []any{nodeID}
	if after > 0 {
		query += ` AND hcl > ?`
		args = append(args, after)
	}
	query += ` ORDER BY hcl ASC LIMIT ?`
	args = append(args, limit)

	rows, err := k.db.Query(query, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var out []GossipObservation
	for rows.Next() {
		var o GossipObservation
		if err := rows.Scan(&o.NodeID, &o.HCL, &o.Fingerprint, &o.SourceID, &o.SourcePath,
			&o.Project, &o.ContentType, &o.Title, &o.Summary, &o.CollectedAt, &o.CreatedAt,
			&o.LineStart, &o.LineEnd, &o.Confidence, &o.IngesterVersion, &o.Trigger, &o.Provenance); err != nil {
			return nil, err
		}
		out = append(out, o)
	}
	return out, rows.Err()
}

// KnowledgeVector returns node_id → max HCL held locally. It is the anti-entropy
// summary exchanged at handshake.
func (k *KnoxDB) KnowledgeVector() (map[string]int64, error) {
	rows, err := k.db.Query(`SELECT node_id, MAX(hcl) FROM observations WHERE node_id<>'' AND hcl IS NOT NULL GROUP BY node_id`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	kv := make(map[string]int64)
	for rows.Next() {
		var nid string
		var hcl int64
		if err := rows.Scan(&nid, &hcl); err != nil {
			return nil, err
		}
		kv[nid] = hcl
	}
	return kv, rows.Err()
}

// ObservePairs returns all observations from other nodes (for consume/echo
// suppression checks).
func (k *KnoxDB) ObserveForeign(nodeID string) (int, error) {
	var n int
	err := k.db.QueryRow(`SELECT COUNT(*) FROM observations WHERE node_id<>? AND node_id<>''`, nodeID).Scan(&n)
	return n, err
}

// UpsertPeer records a peer's last-handshake metadata.
func (k *KnoxDB) UpsertPeer(peerID, addr, name string, maxHCL int64) error {
	_, err := k.db.Exec(
		`INSERT INTO peers (peer_id, addr, name, last_handshake, cursor) VALUES (?, ?, ?, datetime('now'), ?)
		 ON CONFLICT(peer_id) DO UPDATE SET
		   addr=?, name=?,
		   last_handshake=datetime('now'),
		   cursor=?`,
		peerID, addr, name, maxHCL, addr, name, maxHCL,
	)
	return err
}

// ListPeers returns known peers ordered by first-seen.
func (k *KnoxDB) ListPeers() ([]Peer, error) {
	rows, err := k.db.Query(`SELECT peer_id, COALESCE(addr,''), COALESCE(name,''), COALESCE(last_handshake,''), COALESCE(cursor,0), COALESCE(created_at,'') FROM peers ORDER BY created_at`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var peers []Peer
	for rows.Next() {
		var p Peer
		if err := rows.Scan(&p.PeerID, &p.Addr, &p.Name, &p.LastHandshake, &p.Cursor, &p.CreatedAt); err != nil {
			return nil, err
		}
		peers = append(peers, p)
	}
	return peers, rows.Err()
}

// GetPeerByAddr finds a peer whose address matches (statically configured).
func (k *KnoxDB) GetPeerByAddr(addr string) (*Peer, error) {
	row := k.db.QueryRow(`SELECT peer_id, COALESCE(addr,''), COALESCE(name,''), COALESCE(last_handshake,''), COALESCE(cursor,0), COALESCE(created_at,'') FROM peers WHERE addr=?`, addr)
	p := &Peer{}
	err := row.Scan(&p.PeerID, &p.Addr, &p.Name, &p.LastHandshake, &p.Cursor, &p.CreatedAt)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	return p, err
}

// Peer models a row in the peers table.
type Peer struct {
	PeerID        string
	Addr          string
	Name          string
	LastHandshake string
	Cursor        int64
	CreatedAt     string
}