/*
 * @BEGIN LICENSE
 *
 * Psi4: an open-source quantum chemistry software package
 *
 * Copyright (c) 2007-2019 The Psi4 Developers.
 *
 * The copyrights for code used from other parties are included in
 * the corresponding files.
 *
 * This file is part of Psi4.
 *
 * Psi4 is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, version 3.
 *
 * Psi4 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with Psi4; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * @END LICENSE
 */

/*! \file
    \ingroup CCDENSITY
    \brief Enter brief description of file here
*/
#include <cstdio>
#include "psi4/libdpd/dpd.h"
#include "MOInfo.h"
#include "Params.h"
#include "Frozen.h"
#define EXTERN
#include "globals.h"

namespace psi {
namespace ccdensity {

/* FOLD_RHF(): Fold the RHF Fock matrix contributions to the energy
** (or energy derivative) into the two-particle density matrix.  Here
** we are trying to convert from an energy expression of the form:
**
** E = sum_pq Dpq fpq + 1/4 sum_pqrs Gpqrs <pq||rs>
**
** to the form:
**
** E = sum_pq Dpq hpq + 1/4 sum_pqrs Gpqrs <pq||rs>
**
** We do this by shifting some one-particle density matrix components
** into appropriate two-particle density matrix components:
**
** G'pmrm = Dpr + 4 * Gpmrm
**
** One problem is that we need to make sure the resulting density,
** G'pqrs, is still antisymmetric to permutation of p and q or r and
** s.  So, for example, for the Gimkm component we compute:
**
** G'pmrm = Dpr + Gpmrm
** G'mprm = Dpr - Gmprm
** G'pmmr = Dpr - Gpmmr
** G'mpmr = Dpr + Gmpmr
** */

void fold_RHF(struct RHO_Params rho_params) {
    int h, nirreps;
    int i, j, k, l, m, a, b;
    int I, J, K, L, M, A, B;
    int IM, JM, MI, MJ, MK, ML, MA, MB;
    int Gi, Gj, Gk, Gl, Gm, Ga, Gb;
    int *occpi, *virtpi;
    int *occ_off, *vir_off;
    int *occ_sym, *vir_sym;
    int *openpi;
    dpdfile2 D, D1, D2, F;
    dpdbuf4 G, Aints, E, C, DInts, FInts, BInts, G1, G2;
    double one_energy = 0.0, two_energy = 0.0, total_two_energy = 0.0;
    double test_energy = 0.0, tmp;
    double this_energy;

    nirreps = moinfo.nirreps;
    occpi = moinfo.occpi;
    virtpi = moinfo.virtpi;
    occ_off = moinfo.occ_off;
    vir_off = moinfo.vir_off;
    occ_sym = moinfo.occ_sym;
    vir_sym = moinfo.vir_sym;
    openpi = moinfo.openpi;

    if (!params.aobasis && params.debug_) {
        outfile->Printf("\n\tEnergies re-computed from Fock-adjusted CC density:\n");
        outfile->Printf("\t---------------------------------------------------\n");

        global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 0, 0, rho_params.DIJ_lbl);
        global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 0, 0, "h(i,j)");
        this_energy = 2.0 * global_dpd_->file2_dot(&D, &F);
        global_dpd_->file2_close(&F);
        global_dpd_->file2_close(&D);
        one_energy += this_energy;

        global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 1, 1, rho_params.DAB_lbl);
        global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 1, 1, "h(a,b)");
        this_energy = 2.0 * global_dpd_->file2_dot(&D, &F);
        global_dpd_->file2_close(&F);
        global_dpd_->file2_close(&D);
        one_energy += this_energy;

        global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 0, 1, rho_params.DIA_lbl);
        global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 0, 1, "h(i,a)");
        this_energy = 2.0 * global_dpd_->file2_dot(&D, &F);
        global_dpd_->file2_close(&F);
        global_dpd_->file2_close(&D);
        one_energy += this_energy;

        global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 0, 1, rho_params.DAI_lbl);
        global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 0, 1, "h(i,a)");
        this_energy = 2.0 * global_dpd_->file2_dot(&D, &F);
        global_dpd_->file2_close(&F);
        global_dpd_->file2_close(&D);
        one_energy += this_energy;

        outfile->Printf("\tOne-electron energy        = %20.15f\n", one_energy);
    }

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 0, 0, rho_params.DIJ_lbl);
    global_dpd_->file2_mat_init(&D);
    global_dpd_->file2_mat_rd(&D);

    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 0, 0, 0, 0, 0, "GIjKl");
    for (h = 0; h < nirreps; h++) {
        global_dpd_->buf4_mat_irrep_init(&G, h);
        global_dpd_->buf4_mat_irrep_rd(&G, h);

        for (Gm = 0; Gm < nirreps; Gm++) {
            Gi = Gj = h ^ Gm;

            for (i = 0; i < occpi[Gi]; i++) {
                I = occ_off[Gi] + i;
                for (j = 0; j < occpi[Gj]; j++) {
                    J = occ_off[Gj] + j;
                    for (m = 0; m < occpi[Gm]; m++) {
                        M = occ_off[Gm] + m;

                        IM = G.params->rowidx[I][M];
                        JM = G.params->colidx[J][M];
                        MI = G.params->rowidx[M][I];
                        MJ = G.params->colidx[M][J];

                        G.matrix[h][IM][JM] += D.matrix[Gi][i][j];
                        G.matrix[h][MI][MJ] += D.matrix[Gi][i][j];
                    }
                }
            }
        }

        global_dpd_->buf4_mat_irrep_wrt(&G, h);
        global_dpd_->buf4_mat_irrep_close(&G, h);
    }

    if (params.debug_ && !params.aobasis) {
        /* Generate spin-adapted Gijkl just for the energy calculation */
        global_dpd_->buf4_scmcopy(&G, PSIF_CC_GAMMA, "2 Gijkl - Gijlk", 2);
        global_dpd_->buf4_sort_axpy(&G, PSIF_CC_GAMMA, pqsr, 0, 0, "2 Gijkl - Gijlk", -1);
        global_dpd_->buf4_close(&G);

        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 0, 0, 0, 0, 0, "2 Gijkl - Gijlk");
        global_dpd_->buf4_init(&Aints, PSIF_CC_AINTS, 0, 0, 0, 0, 0, 0, "A <ij|kl>");
        two_energy += global_dpd_->buf4_dot(&Aints, &G);
        global_dpd_->buf4_close(&Aints);
        total_two_energy += two_energy;
        outfile->Printf("\tIJKL energy                = %20.15f\n", two_energy);
    }
    global_dpd_->buf4_close(&G);

    global_dpd_->file2_mat_close(&D);
    global_dpd_->file2_close(&D);

    global_dpd_->file2_init(&D1, PSIF_CC_OEI, 0, 0, 1, rho_params.DIA_lbl);
    global_dpd_->file2_mat_init(&D1);
    global_dpd_->file2_mat_rd(&D1);
    global_dpd_->file2_init(&D2, PSIF_CC_OEI, 0, 0, 1, rho_params.DAI_lbl);
    global_dpd_->file2_mat_init(&D2);
    global_dpd_->file2_mat_rd(&D2);

    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 0, 10, 0, 10, 0, "GIjKa");
    for (h = 0; h < nirreps; h++) {
        global_dpd_->buf4_mat_irrep_init(&G, h);
        global_dpd_->buf4_mat_irrep_rd(&G, h);

        for (Gm = 0; Gm < nirreps; Gm++) {
            Gi = Ga = h ^ Gm;

            for (i = 0; i < (occpi[Gi] - openpi[Gi]); i++) {
                I = occ_off[Gi] + i;
                for (a = 0; a < virtpi[Ga]; a++) {
                    A = vir_off[Ga] + a;
                    for (m = 0; m < occpi[Gm]; m++) {
                        M = occ_off[Gm] + m;

                        MI = G.params->rowidx[M][I];
                        MA = G.params->colidx[M][A];

                        G.matrix[h][MI][MA] += 0.5 * (D1.matrix[Gi][i][a] + D2.matrix[Gi][i][a]);
                    }
                }
            }
        }

        global_dpd_->buf4_mat_irrep_wrt(&G, h);
        global_dpd_->buf4_mat_irrep_close(&G, h);
    }

    if (params.debug_ && !params.aobasis) {
        /* Generate spin-adapted Gijka just for the energy calculation */
        global_dpd_->buf4_scmcopy(&G, PSIF_CC_GAMMA, "2 Gijka - Gjika", 2);
        global_dpd_->buf4_sort_axpy(&G, PSIF_CC_GAMMA, qprs, 0, 10, "2 Gijka - Gjika", -1);
        global_dpd_->buf4_close(&G);

        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 0, 10, 0, 10, 0, "2 Gijka - Gjika");
        global_dpd_->buf4_init(&E, PSIF_CC_EINTS, 0, 0, 10, 0, 10, 0, "E <ij|ka>");
        /* The factor of 4 here is necessary because Gijka is multiplied by 1/2 in Gijka.cc */
        two_energy = 4 * global_dpd_->buf4_dot(&E, &G);
        global_dpd_->buf4_close(&E);
        total_two_energy += two_energy;
        outfile->Printf("\tIJKA energy                = %20.15f\n", two_energy);
    }
    global_dpd_->buf4_close(&G);

    global_dpd_->file2_mat_close(&D1);
    global_dpd_->file2_close(&D1);
    global_dpd_->file2_mat_close(&D2);
    global_dpd_->file2_close(&D2);

    if (!params.aobasis && params.debug_) {
        /* Generate spin-adapted Gijab jut for energy calculation */
        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 0, 5, 0, 5, 0, "GIjAb");
        global_dpd_->buf4_scmcopy(&G, PSIF_CC_GAMMA, "2 Gijab - Gijba", 2);
        global_dpd_->buf4_sort_axpy(&G, PSIF_CC_GAMMA, pqsr, 0, 5, "2 Gijab - Gijba", -1);
        global_dpd_->buf4_close(&G);
        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 0, 5, 0, 5, 0, "2 Gijab - Gijba");
        global_dpd_->buf4_init(&DInts, PSIF_CC_DINTS, 0, 0, 5, 0, 5, 0, "D <ij|ab>");
        two_energy = 2 * global_dpd_->buf4_dot(&G, &DInts);
        global_dpd_->buf4_close(&G);
        global_dpd_->buf4_close(&DInts);

        total_two_energy += two_energy;
        outfile->Printf("\tIJAB energy                = %20.15f\n", two_energy);
    }

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 1, 1, rho_params.DAB_lbl);
    global_dpd_->file2_mat_init(&D);
    global_dpd_->file2_mat_rd(&D);

    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 10, 10, 10, 10, 0, "GIBJA");
    for (h = 0; h < nirreps; h++) {
        global_dpd_->buf4_mat_irrep_init(&G, h);
        global_dpd_->buf4_mat_irrep_rd(&G, h);

        for (Gm = 0; Gm < nirreps; Gm++) {
            Ga = Gb = h ^ Gm;

            for (b = 0; b < (virtpi[Gb] - openpi[Gb]); b++) {
                B = vir_off[Gb] + b;
                for (a = 0; a < (virtpi[Ga] - openpi[Ga]); a++) {
                    A = vir_off[Ga] + a;
                    for (m = 0; m < occpi[Gm]; m++) {
                        M = occ_off[Gm] + m;

                        MB = G.params->rowidx[M][B];
                        MA = G.params->colidx[M][A];

                        G.matrix[h][MB][MA] += D.matrix[Ga][a][b];
                    }
                }
            }
        }

        global_dpd_->buf4_mat_irrep_wrt(&G, h);
        global_dpd_->buf4_mat_irrep_close(&G, h);
    }

    global_dpd_->buf4_close(&G);
    global_dpd_->file2_mat_close(&D);
    global_dpd_->file2_close(&D);

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 1, 1, rho_params.DAB_lbl);
    global_dpd_->file2_mat_init(&D);
    global_dpd_->file2_mat_rd(&D);

    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 10, 10, 10, 10, 0, "GIbJa");
    for (h = 0; h < nirreps; h++) {
        global_dpd_->buf4_mat_irrep_init(&G, h);
        global_dpd_->buf4_mat_irrep_rd(&G, h);

        for (Gm = 0; Gm < nirreps; Gm++) {
            Ga = Gb = h ^ Gm;

            for (b = 0; b < virtpi[Gb]; b++) {
                B = vir_off[Gb] + b;
                for (a = 0; a < virtpi[Ga]; a++) {
                    A = vir_off[Ga] + a;
                    for (m = 0; m < occpi[Gm]; m++) {
                        M = occ_off[Gm] + m;

                        MB = G.params->rowidx[M][B];
                        MA = G.params->colidx[M][A];

                        G.matrix[h][MB][MA] += D.matrix[Ga][a][b];
                    }
                }
            }
        }

        global_dpd_->buf4_mat_irrep_wrt(&G, h);
        global_dpd_->buf4_mat_irrep_close(&G, h);
    }

    global_dpd_->buf4_close(&G);

    global_dpd_->file2_mat_close(&D);
    global_dpd_->file2_close(&D);

    if (!params.aobasis && params.debug_) {
        two_energy = 0.0;
        global_dpd_->buf4_init(&C, PSIF_CC_CINTS, 0, 10, 10, 10, 10, 0, "C <ia||jb>");
        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 10, 10, 10, 10, 0, "GIBJA");
        two_energy += 2.0 * global_dpd_->buf4_dot(&G, &C);
        global_dpd_->buf4_close(&G);

        global_dpd_->buf4_init(&C, PSIF_CC_CINTS, 0, 10, 10, 10, 10, 0, "C <ia|jb>");
        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 10, 10, 10, 10, 0, "GIbJa");
        two_energy += 2.0 * global_dpd_->buf4_dot(&G, &C);
        global_dpd_->buf4_close(&G);

        global_dpd_->buf4_init(&DInts, PSIF_CC_DINTS, 0, 10, 10, 10, 10, 0, "D <ij|ab> (ib,ja)");
        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 10, 10, 10, 10, 0, "GIbjA");
        two_energy -= 2.0 * global_dpd_->buf4_dot(&G, &DInts);
        global_dpd_->buf4_close(&G);
        global_dpd_->buf4_close(&DInts);

        total_two_energy += two_energy;
        outfile->Printf("\tIBJA energy                = %20.15f\n", two_energy);

        /* Generate spin-adapted Gciab just for energy calculation */
        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 11, 5, 11, 5, 0, "GCiAb");
        global_dpd_->buf4_scmcopy(&G, PSIF_CC_GAMMA, "2 Gciab - Gciba", 2);
        global_dpd_->buf4_sort_axpy(&G, PSIF_CC_GAMMA, pqsr, 11, 5, "2 Gciab - Gciba", -1);
        global_dpd_->buf4_close(&G);

        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 11, 5, 11, 5, 0, "2 Gciab - Gciba");
        global_dpd_->buf4_init(&FInts, PSIF_CC_FINTS, 0, 10, 5, 10, 5, 0, "F <ia|bc>");
        global_dpd_->buf4_sort(&FInts, PSIF_CC_FINTS, qpsr, 11, 5, "F <ai|bc>");
        global_dpd_->buf4_close(&FInts);
        global_dpd_->buf4_init(&FInts, PSIF_CC_FINTS, 0, 11, 5, 11, 5, 0, "F <ai|bc>");
        /* The factor of 4 here is necessary because Gciab is multiplied by 1/2 in Gciab.cc */
        two_energy = 4 * global_dpd_->buf4_dot(&FInts, &G);
        global_dpd_->buf4_close(&FInts);
        global_dpd_->buf4_close(&G);
        total_two_energy += two_energy;
        outfile->Printf("\tCIAB energy                = %20.15f\n", two_energy);

        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 5, 5, 5, 5, 0, "GAbCd");

        global_dpd_->buf4_scmcopy(&G, PSIF_CC_GAMMA, "2 Gabcd - Gabdc", 2);
        global_dpd_->buf4_sort_axpy(&G, PSIF_CC_GAMMA, pqsr, 5, 5, "2 Gabcd - Gabdc", -1);
        global_dpd_->buf4_close(&G);

        global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 5, 5, 5, 5, 0, "2 Gabcd - Gabdc");
        global_dpd_->buf4_init(&BInts, PSIF_CC_BINTS, 0, 5, 5, 5, 5, 0, "B <ab|cd>");
        two_energy = global_dpd_->buf4_dot(&BInts, &G);
        global_dpd_->buf4_close(&BInts);
        global_dpd_->buf4_close(&G);
        total_two_energy += two_energy;
        outfile->Printf("\tABCD energy                = %20.15f\n", two_energy);

        outfile->Printf("\tTotal two-electron energy  = %20.15f\n", total_two_energy);
        if (params.ground) {
            // outfile->Printf( "\tCCSD correlation energy    = %20.15f\n",
            //	  one_energy + total_two_energy);
            // outfile->Printf( "\tTotal CCSD energy          = %20.15f\n",
            //	  one_energy + total_two_energy + moinfo.eref);
            outfile->Printf("\t%7s correlation energy = %20.15f\n",
                            params.wfn == "CCSD_T" ? "CCSD(T)" : params.wfn.c_str(), one_energy + total_two_energy);
            outfile->Printf("\tTotal %7s energy       = %20.15f\n",
                            params.wfn == "CCSD_T" ? "CCSD(T)" : params.wfn.c_str(),
                            one_energy + total_two_energy + moinfo.eref);
        } else {
            outfile->Printf("\tTotal EOM CCSD correlation energy        = %20.15f\n", one_energy + total_two_energy);
            outfile->Printf("\tCCSD correlation + EOM excitation energy = %20.15f\n", moinfo.ecc + params.cceom_energy);
            outfile->Printf("\tTotal EOM CCSD energy                    = %20.15f\n",
                            one_energy + total_two_energy + moinfo.eref);
        }
    }
}
}  // namespace ccdensity
}  // namespace psi
