  Very-high-energy (VHE; $\geq 10$ GeV) photons are expected from the nearest
and brightest Gamma-ray bursts (GRBs). VHE photons, at energies higher than 300
GeV, were recently reported by the MAGIC collaboration for this burst.
Immediately, GRB 190114C was followed up by a massive observational campaign
covering a large fraction of the electromagnetic spectrum. In this paper, we
obtain the LAT light curve of GRB 190114C and show that it exhibits similar
features to other bright LAT-detected bursts; the first high-energy photon
($\geq$ 100 MeV) is delayed with the onset of the prompt phase and the flux
light curve exhibits a long-lived emission (lasting much longer than the prompt
phase) and a short-lasting bright peak (located at the beginning of long-lived
emission). Analyzing the multi-wavelength observations, we show that the
short-lasting LAT and GBM bright peaks are consistent with the synchrotron
self-Compton reverse-shock model and the long-lived observations with the
standard synchrotron forward-shock model that evolves from a stratified
stellar-wind like medium to a uniform ISM-like medium. Given the best-fit
values, a bright optical flash produced by synchrotron reverse-shock emission
is expected. From our analysis we infer that the high-energy photons are
produced in the deceleration phase of the outflow and some additional processes
to synchrotron in the forward shocks should be considered to properly describe
the LAT photons with energies beyond the synchrotron limit. Moreover, we claim
that an outflow endowed with magnetic fields could describe the polarization
and properties exhibited in the light curve of GRB 190114C.
