  We propose a single-photon router using a single atom with an inversion
center coupled to quantum multichannels made of coupled-resonator waveguides.
We show that the spontaneous emission of the atom can direct single photons
from one quantum channel into another. The on-demand classical field perfectly
switches-off the single-photon routing due to the quantum interference in the
atomic amplitudes of optical transitions. Total reflections in the incident
channel are due to the photonic bound state in the continuum. Two virtual
channels, named as scatter-free and controllable channels, are found, which are
coherent superpositions of quantum channels. Any incident photon in the
scatter-free channel is totally transmitted. The propagating states of the
controllable channel are orthogonal to those of the scatter-free channel.
Single photons in the controllable channel can be perfectly reflected or
transmitted by the atom.
