Add concurrency caps, the two-pane web UI, AGENTS.md, and plan status

internal/store/queue.go

@@ -0,0 +1,99 @@
+package store
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"time"
+
+	"g.fc.run/misc/byre/internal/api"
+)
+
+type QueuedTurn struct {
+	SessionID string
+	Vendor    api.AgentSessionVendor
+	Actor     string
+	Text      string
+	CreatedAt time.Time
+}
+
+func (s *Store) SessionStarted(ctx context.Context, sessionID string) (bool, error) {
+	started := false
+	err := s.db.QueryRowContext(ctx, `SELECT EXISTS (SELECT 1 FROM events WHERE agent_session_id = ? AND kind = 'user.message')`, sessionID).Scan(&started)
+	return started, err
+}
+
+func (s *Store) CountRunning(ctx context.Context) (map[api.AgentSessionVendor]int, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT vendor, COUNT(*) FROM agent_sessions WHERE state = ? GROUP BY vendor`, string(api.AgentSessionStateRunning))
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	counts := map[api.AgentSessionVendor]int{}
+	for rows.Next() {
+		vendor := ""
+		n := 0
+		err = rows.Scan(&vendor, &n)
+		if err != nil {
+			return nil, err
+		}
+		counts[api.AgentSessionVendor(vendor)] = n
+	}
+	return counts, rows.Err()
+}
+
+func (s *Store) EnqueueTurn(ctx context.Context, q QueuedTurn) error {
+	return s.write(ctx, func(tx *sql.Tx, emit emitFunc) error {
+		_, err := tx.ExecContext(ctx, `INSERT INTO turn_queue (session_id, actor, text, created_at) VALUES (?, ?, ?, ?)`,
+			q.SessionID, q.Actor, q.Text, formatTime(q.CreatedAt))
+		return err
+	})
+}
+
+func (s *Store) QueuedTurns(ctx context.Context) ([]QueuedTurn, error) {
+	rows, err := s.db.QueryContext(ctx, `
+		SELECT q.session_id, s.vendor, q.actor, q.text, q.created_at
+		FROM turn_queue q JOIN agent_sessions s ON s.id = q.session_id
+		ORDER BY q.created_at
+	`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	turns := []QueuedTurn{}
+	for rows.Next() {
+		q := QueuedTurn{}
+		vendor := ""
+		createdAt := ""
+		err = rows.Scan(&q.SessionID, &vendor, &q.Actor, &q.Text, &createdAt)
+		if err != nil {
+			return nil, err
+		}
+		q.Vendor = api.AgentSessionVendor(vendor)
+		q.CreatedAt, err = parseTime(createdAt)
+		if err != nil {
+			return nil, err
+		}
+		turns = append(turns, q)
+	}
+	return turns, rows.Err()
+}
+
+func (s *Store) DeleteQueuedTurn(ctx context.Context, sessionID string) error {
+	return s.write(ctx, func(tx *sql.Tx, emit emitFunc) error {
+		res, err := tx.ExecContext(ctx, `DELETE FROM turn_queue WHERE session_id = ?`, sessionID)
+		if err != nil {
+			return err
+		}
+		n, err := res.RowsAffected()
+		if err != nil {
+			return err
+		}
+		if n == 0 {
+			return errors.Join(ErrNotFound, errors.New("no queued turn for session "+sessionID))
+		}
+		return nil
+	})
+}