//! @file vcs_TP.cpp
#include "cantera/equil/vcs_solve.h"
#include "cantera/equil/vcs_VolPhase.h"

namespace Cantera
{
int VCS_SOLVE::vcs_TP(int ipr, int ip1, int maxit, double T_arg, double pres_arg)
{
    /*
     *        Store the temperature and pressure in the private global variables
     */
    m_temperature = T_arg;
    m_pressurePA = pres_arg;
    /*
     *        Evaluate the standard state free energies
     *        at the current temperatures and pressures.
     */
    int iconv = vcs_evalSS_TP(ipr, ip1, m_temperature, pres_arg);

    /*
     *        Prepare the problem data:
     *          ->nondimensionalize the free energies using
     *            the divisor, R * T
     */
    vcs_nondim_TP();
    /*
     * Prep the fe field
     */
    vcs_fePrep_TP();
    /*
     *      Decide whether we need an initial estimate of the solution
     *      If so, go get one. If not, then
     */
    if (m_doEstimateEquil) {
        int retn = vcs_inest_TP();
        if (retn != VCS_SUCCESS) {
            plogf("vcs_inest_TP returned a failure flag\n");
        }
    }
    /*
     *        Solve the problem at a fixed Temperature and Pressure
     * (all information concerning Temperature and Pressure has already
     *  been derived. The free energies are now in dimensionless form.)
     */
    iconv  = vcs_solve_TP(ipr, ip1, maxit);

    /*
     *        Redimensionalize the free energies using
     *        the reverse of vcs_nondim to add back units.
     */
    vcs_redim_TP();
    /*
     *        Return the convergence success flag.
     */
    return iconv;
}

int VCS_SOLVE::vcs_evalSS_TP(int ipr, int ip1, double Temp, double pres)
{
    /*
     *  We need to special case VCS_UNITS_UNITLESS, here.
     *      cpc_ts_GStar_calc() returns units of Kelvin. Also, the temperature
     *      comes into play in calculating the ideal equation of state
     *      contributions, and other equations of state also. Therefore,
     *      we will emulate the VCS_UNITS_KELVIN case, here by changing
     *      the initial Gibbs free energy units to Kelvin before feeding
     *      them to the cpc_ts_GStar_calc() routine. Then, we will revert
     *      them back to unitless at the end of this routine.
     */

    for (size_t iph = 0; iph < m_numPhases; iph++) {
        vcs_VolPhase* vph = m_VolPhaseList[iph];
        vph->setState_TP(m_temperature, m_pressurePA);
        vph->sendToVCS_GStar(&m_SSfeSpecies[0]);
    }

    if (m_VCS_UnitsFormat == VCS_UNITS_UNITLESS) {
        for (size_t i = 0; i < m_numSpeciesTot; ++i) {
            m_SSfeSpecies[i]  /= Temp;
        }
    }
    return VCS_SUCCESS;
}

void  VCS_SOLVE::vcs_fePrep_TP(void)
{
    for (size_t i = 0; i < m_numSpeciesTot; ++i) {
        /*
         *        For single species phases, initialize the chemical
         *        potential with the value of the standard state chemical
         *        potential. This value doesn't change during the calculation
         */
        if (m_SSPhase[i]) {
            m_feSpecies_old[i] = m_SSfeSpecies[i];
            m_feSpecies_new[i] = m_SSfeSpecies[i];
        }
    }
}

}