package spool

import (
	"context"
	"errors"

	rvboxv1 "github.com/rvbox/rvbox/gen/go/rvbox/v1"
)

// Telemetry is the bounded durable-spool state exposed as client gauges. It
// contains no command body, output, UUID, or client identity.
type Telemetry struct {
	QueuedCommands uint64
	ChargedBytes   uint64
}

func (store *Store) Telemetry(ctx context.Context) (Telemetry, error) {
	if store == nil {
		return Telemetry{}, errors.New("client spool is unavailable")
	}
	store.mu.Lock()
	defer store.mu.Unlock()
	if store.db == nil {
		return Telemetry{}, errors.New("client spool is closed")
	}
	var result Telemetry
	if err := store.db.QueryRowContext(ctx, `SELECT count(*) FROM commands WHERE terminal = 0 AND phase IN (?, ?)`, uint32(rvboxv1.CommandLifecycle_COMMAND_QUEUED), uint32(rvboxv1.CommandLifecycle_COMMAND_DISPATCHED)).Scan(&result.QueuedCommands); err != nil {
		return Telemetry{}, err
	}
	if err := store.db.QueryRowContext(ctx, `SELECT client_total_charged_bytes FROM spool_counters WHERE singleton = 1`).Scan(&result.ChargedBytes); err != nil {
		return Telemetry{}, err
	}
	return result, nil
}