package registry

import "os"

// ArtifactHosts discovers candidates; it supplies no installation authority.
// Include orphan and inactive timers. Due-time filtering would hide obligations.
func (r *Registry) ArtifactHosts() ([]string, error) {
	if r.remote != nil {
		out, err := r.remote.call(nil, remoteRequest{Method: "ArtifactHosts"}, nil)
		return out.Hosts, err
	}
	rows, err := r.sql.Query(`SELECT host FROM routes UNION SELECT host FROM timers ORDER BY host LIMIT 8193`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var hosts []string
	for rows.Next() {
		var host string
		if err := rows.Scan(&host); err != nil {
			return nil, err
		}
		if len(hosts) == 8192 {
			return nil, os.ErrPermission
		}
		hosts = append(hosts, host)
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	return hosts, nil
}