  In the disk-corona model, the X-ray spectrum of a stellar-mass black hole in
an X-ray binary is characterized by three components: a thermal component from
a thin and cold accretion disk, a Comptonized component from a hot corona, and
a reflection component produced by illumination of the cold disk by the hot
corona. In this paper, we present ZIJI, which is a model to calculate the X-ray
spectrum of black hole X-ray binaries in the disk-corona model. The accretion
disk is described by the Novikov-Thorne model. The reflection spectrum is
produced by the direct radiation from the corona as well as by the returning
radiation of the thermal and reflection components and is calculated
considering the actual spectrum illuminating the disk. If we turn the corona
off, the reflection spectrum is completely generated by the returning radiation
of the thermal component, as it may happen for some sources in soft spectral
states. The user decides the radial density profile of the accretion disk and
the ionization parameter is calculated self-consistently at any radial
coordinate of the disk from the illuminating X-ray flux and the local electron
density. We show the predictions of ZIJI in different regimes. We discuss
current limitations of our model as well as the next steps to improve it.
