kami
132 lines
3.7 KiB
Go
132 lines
3.7 KiB
Go
package store
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import (
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"context"
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"encoding/binary"
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"fmt"
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"math"
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"sort"
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"time"
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)
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// Note — a recall/preference item. No predicate reads it (facts are for that);
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// query-answering ranks notes by embedding cosine. Score is set by QueryNotes.
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type Note struct {
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ID int64
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Ts time.Time
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Text string
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Source string
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Score float64
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}
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// WriteNote appends a note with its embedding (stored as a little-endian
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// float32 BLOB). Source is provenance (tap:voice, etc.).
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func (s *Store) WriteNote(ctx context.Context, ts time.Time, text string, embedding []float32, source string) (int64, error) {
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res, err := s.db.ExecContext(ctx,
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`INSERT INTO notes (ts, text, embedding, source) VALUES (?,?,?,?)`,
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ts.UnixMilli(), text, floatsToBlob(embedding), source)
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if err != nil {
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return 0, fmt.Errorf("write note: %w", err)
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}
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id, _ := res.LastInsertId()
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return id, nil
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}
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// QueryNotes returns the top-k notes by cosine similarity to embedding, highest
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// first (ties broken newest-first). Fewer than k notes ⇒ returns what exists.
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//
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// ponytail: brute-force O(n) cosine over every note each query. Add sqlite-vec
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// or an ANN index only when note count or latency actually bites — at personal
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// scale (hundreds–thousands) a full scan is sub-millisecond.
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func (s *Store) QueryNotes(ctx context.Context, embedding []float32, k int) ([]Note, error) {
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rows, err := s.db.QueryContext(ctx, `SELECT id, ts, text, embedding, source FROM notes`)
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if err != nil {
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return nil, fmt.Errorf("query notes: %w", err)
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}
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defer rows.Close()
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var out []Note
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for rows.Next() {
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var n Note
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var tsMilli int64
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var blob []byte
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if err := rows.Scan(&n.ID, &tsMilli, &n.Text, &blob, &n.Source); err != nil {
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return nil, err
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}
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n.Ts = time.UnixMilli(tsMilli).UTC()
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n.Score = cosine(embedding, blobToFloats(blob))
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out = append(out, n)
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}
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if err := rows.Err(); err != nil {
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return nil, err
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}
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sort.Slice(out, func(i, j int) bool {
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if out[i].Score != out[j].Score {
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return out[i].Score > out[j].Score
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}
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return out[i].Ts.After(out[j].Ts) // newest breaks ties
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})
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if k > 0 && len(out) > k {
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out = out[:k]
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}
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return out, nil
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}
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// RecentNotes returns the newest n notes, newest first — a browse view (no
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// embedding math; Score stays 0). This is the read surface for /dash: notes
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// captured by voice are otherwise only reachable through semantic query.
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func (s *Store) RecentNotes(ctx context.Context, n int) ([]Note, error) {
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rows, err := s.db.QueryContext(ctx,
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`SELECT id, ts, text, source FROM notes ORDER BY ts DESC LIMIT ?`, n)
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if err != nil {
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return nil, fmt.Errorf("recent notes: %w", err)
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}
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defer rows.Close()
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var out []Note
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for rows.Next() {
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var nt Note
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var tsMilli int64
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if err := rows.Scan(&nt.ID, &tsMilli, &nt.Text, &nt.Source); err != nil {
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return nil, err
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}
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nt.Ts = time.UnixMilli(tsMilli).UTC()
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out = append(out, nt)
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}
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return out, rows.Err()
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}
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// cosine similarity. Embedder vectors are L2-normalized, so this is just the
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// dot product — but normalize defensively in case a caller passes a raw vector.
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func cosine(a, b []float32) float64 {
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if len(a) != len(b) || len(a) == 0 {
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return 0
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}
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var dot, na, nb float64
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for i := range a {
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dot += float64(a[i]) * float64(b[i])
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na += float64(a[i]) * float64(a[i])
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nb += float64(b[i]) * float64(b[i])
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}
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if na == 0 || nb == 0 {
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return 0
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}
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return dot / (math.Sqrt(na) * math.Sqrt(nb))
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}
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func floatsToBlob(v []float32) []byte {
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b := make([]byte, 4*len(v))
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for i, f := range v {
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binary.LittleEndian.PutUint32(b[4*i:], math.Float32bits(f))
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}
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return b
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}
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func blobToFloats(b []byte) []float32 {
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v := make([]float32, len(b)/4)
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for i := range v {
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v[i] = math.Float32frombits(binary.LittleEndian.Uint32(b[4*i:]))
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}
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return v
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}
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