/*
 * @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 DPD
    \brief Enter brief description of file here
*/
#include <cstdio>
#include <cstdlib>
#include "psi4/libqt/qt.h"
#include "dpd.h"
#include "psi4/psi4-dec.h"
namespace psi {

/* dpd_buf4_mat_irrep_wrt(): Writes an entire irrep from disk into a dpd
** four-index buffer using the "rules" specified when the buffer was
** initialized by dpd_buf4_init().
**
** Arguments:
**   dpdbuf4 *Buf: A pointer to the dpdbuf where the data is
**                       stored.
**   int irrep: The irrep number to be written.
**
** The case numbers are the same as those from buf4_mat_irrep_rd().
** Unpacking indices on the write has not been tested, and should be currently
** disabled.
**
** T. Daniel Crawford
** December 1996
**
** Modified for caching.
** TDC
** September 1999
*/

int DPD::buf4_mat_irrep_wrt(dpdbuf4 *Buf, int irrep) {
    int method, filerow, all_buf_irrep;
    int pq, rs;         /* dpdfile row and column indices */
    int p, q, r, s;     /* orbital indices */
    int bufpq, bufrs;   /* Input dpdbuf row and column indices */
    int rowtot, coltot; /* dpdfile row and column dimensions */
    int b_perm_pq, b_perm_rs, b_peq, b_res;
    int f_perm_pq, f_perm_rs, f_peq, f_res;
    int permute;
    double value;
    long int size;

    all_buf_irrep = Buf->file.my_irrep;

    /* Row and column dimensions in the DPD file */
    rowtot = Buf->file.params->rowtot[irrep];
    coltot = Buf->file.params->coltot[irrep ^ all_buf_irrep];
    size = ((long)rowtot) * ((long)coltot);

    /* Index packing information */
    b_perm_pq = Buf->params->perm_pq;
    b_perm_rs = Buf->params->perm_rs;
    f_perm_pq = Buf->file.params->perm_pq;
    f_perm_rs = Buf->file.params->perm_rs;
    b_peq = Buf->params->peq;
    b_res = Buf->params->res;
    f_peq = Buf->file.params->peq;
    f_res = Buf->file.params->res;

    /* Exit if buffer is antisymmetrized */
    if (Buf->anti) {
        printf("\n\tCannot write antisymmetrized buffer\n");
        printf("\tback to original DPD file!\n");
        exit(PSI_RETURN_FAILURE);
    }

    if ((b_perm_pq == f_perm_pq) && (b_perm_rs == f_perm_rs) && (b_peq == f_peq) && (b_res == f_res))
        method = 12;
    else if ((b_perm_pq != f_perm_pq) && (b_perm_rs == f_perm_rs) && (b_res == f_res)) {
        if (f_perm_pq && !b_perm_pq)
            method = 21;
        else if (!f_perm_pq && b_perm_pq)
            method = 23;
        else {
            printf("\n\tInvalid second-level method!\n");
            exit(PSI_RETURN_FAILURE);
        }
    } else if ((b_perm_pq == f_perm_pq) && (b_perm_rs != f_perm_rs) && (b_peq == f_peq)) {
        if (f_perm_rs && !b_perm_rs)
            method = 31;
        else if (!f_perm_rs && b_perm_rs)
            method = 33;
        else {
            printf("\n\tInvalid third-level method!\n");
            exit(PSI_RETURN_FAILURE);
        }
    } else if ((b_perm_pq != f_perm_pq) && (b_perm_rs != f_perm_rs)) {
        if (f_perm_pq && !b_perm_pq) {
            if (f_perm_rs && !b_perm_rs)
                method = 41;
            else if (!f_perm_rs && b_perm_rs)
                method = 42;
        } else if (!f_perm_pq && b_perm_pq) {
            if (f_perm_rs && !b_perm_rs)
                method = 43;
            else if (!f_perm_rs && b_perm_rs)
                method = 45;
        } else {
            printf("\n\tInvalid fourth-level method!\n");
            exit(PSI_RETURN_FAILURE);
        }
    } else {
        printf("\n\tInvalid method in dpd_buf_mat_irrep_rd!\n");
        exit(PSI_RETURN_FAILURE);
    }

    switch (method) {
        case 12: /* No change in pq or rs */

#ifdef DPD_TIMER
            timer_on("buf_wrt_12");
#endif

            if (Buf->file.incore && size) {
                file4_cache_dirty(&(Buf->file));
            }
            /*
          memcpy((void *) &(Buf->file.matrix[irrep][0][0]),
             (const void *) &(Buf->matrix[irrep][0][0]),
             sizeof(double)*rowtot*coltot);
    */
            else {
                Buf->file.matrix[irrep] = Buf->matrix[irrep];
                file4_mat_irrep_wrt(&(Buf->file), irrep);
            }

#ifdef DPD_TIMER
            timer_off("buf_wrt_12");
#endif

            break;
        case 21: /* Pack pq; no change in rs */
            /* Prepare the output buffer for the output DPD file */
            file4_mat_irrep_row_init(&(Buf->file), irrep);

            /* Loop over rows in the dpdfile */
            for (pq = 0; pq < rowtot; pq++) {
                p = Buf->file.params->roworb[irrep][pq][0];
                q = Buf->file.params->roworb[irrep][pq][1];
                bufpq = Buf->params->rowidx[p][q];
                filerow = Buf->file.incore ? pq : 0;

                /* Loop over the columns in the dpdbuf */
                for (rs = 0; rs < coltot; rs++) {
                    bufrs = rs;

                    value = Buf->matrix[irrep][bufpq][bufrs];

                    /* Assign the value */
                    Buf->file.matrix[irrep][filerow][rs] = value;
                }

                /* Write out the row */
                file4_mat_irrep_row_wrt(&(Buf->file), irrep, pq);
            }

            /* Close the input buffer */
            file4_mat_irrep_row_close(&(Buf->file), irrep);

            break;
        case 23: /* Unpack pq; no change in rs */
            /* I don't know if I'll ever use this, so I'll avoid it for now */
            printf("\n\tShould you be using method %d?\n", method);
            exit(PSI_RETURN_FAILURE);
            /* Prepare the output buffer for the output DPD file */
            file4_mat_irrep_row_init(&(Buf->file), irrep);

            /* Loop over rows in the dpdfile */
            for (pq = 0; pq < rowtot; pq++) {
                p = Buf->file.params->roworb[irrep][pq][0];
                q = Buf->file.params->roworb[irrep][pq][1];
                bufpq = Buf->params->rowidx[p][q];

                filerow = Buf->file.incore ? pq : 0;

                /* Set the permutation operator's value */
                permute = ((p < q) && (b_perm_pq < 0) ? -1 : 1);

                /* Loop over the columns in the dpdbuf */
                for (rs = 0; rs < coltot; rs++) {
                    bufrs = rs;

                    value = Buf->matrix[irrep][bufpq][bufrs];

                    /* Assign the value */
                    Buf->file.matrix[irrep][filerow][rs] = permute * value;
                }

                /* Write out the row */
                file4_mat_irrep_row_wrt(&(Buf->file), irrep, pq);
            }

            /* Close the input buffer */
            file4_mat_irrep_row_close(&(Buf->file), irrep);

            break;
        case 31: /* No change in pq; pack rs */
            /* Prepare the output buffer for the output DPD file */
            file4_mat_irrep_row_init(&(Buf->file), irrep);

            /* Loop over rows in the dpdbuf/dpdfile */
            for (pq = 0; pq < rowtot; pq++) {
                bufpq = pq;

                filerow = Buf->file.incore ? pq : 0;

                /* Loop over the columns in the dpdfile */
                for (rs = 0; rs < coltot; rs++) {
                    r = Buf->file.params->colorb[irrep ^ all_buf_irrep][rs][0];
                    s = Buf->file.params->colorb[irrep ^ all_buf_irrep][rs][1];
                    bufrs = Buf->params->colidx[r][s];

                    value = Buf->matrix[irrep][bufpq][bufrs];

                    /* Assign the value */
                    Buf->file.matrix[irrep][filerow][rs] = value;
                }

                /* Write out the row */
                file4_mat_irrep_row_wrt(&(Buf->file), irrep, pq);
            }

            /* Close the input buffer */
            file4_mat_irrep_row_close(&(Buf->file), irrep);

            break;
        case 33: /* No change in pq; unpack rs */
            /* I'm not sure if I'll ever need this, so I'm removing it for now */
            printf("\n\tShould you be using method %d?\n", method);
            exit(PSI_RETURN_FAILURE);
            /* Prepare the output buffer for the output DPD file */
            file4_mat_irrep_row_init(&(Buf->file), irrep);

            /* Loop over rows in the dpdbuf/dpdfile */
            for (pq = 0; pq < rowtot; pq++) {
                bufpq = pq;

                filerow = Buf->file.incore ? pq : 0;

                /* Loop over the columns in the dpdfile */
                for (rs = 0; rs < coltot; rs++) {
                    r = Buf->file.params->colorb[irrep ^ all_buf_irrep][rs][0];
                    s = Buf->file.params->colorb[irrep ^ all_buf_irrep][rs][1];
                    bufrs = Buf->params->colidx[r][s];

                    value = Buf->matrix[irrep][bufpq][bufrs];

                    /* Assign the value */
                    Buf->file.matrix[irrep][filerow][rs] = value;
                }

                /* Write out the row */
                file4_mat_irrep_row_wrt(&(Buf->file), irrep, pq);
            }

            /* Close the input buffer */
            file4_mat_irrep_row_close(&(Buf->file), irrep);

            break;
        case 41: /* Pack pq and rs */
            /* Prepare the output buffer for the output DPD file */
            file4_mat_irrep_row_init(&(Buf->file), irrep);

            /* Loop over rows in the dpdfile */
            for (pq = 0; pq < rowtot; pq++) {
                p = Buf->file.params->roworb[irrep][pq][0];
                q = Buf->file.params->roworb[irrep][pq][1];
                bufpq = Buf->params->rowidx[p][q];

                filerow = Buf->file.incore ? pq : 0;

                /* Loop over the columns in the dpdfile */
                for (rs = 0; rs < coltot; rs++) {
                    r = Buf->file.params->colorb[irrep ^ all_buf_irrep][rs][0];
                    s = Buf->file.params->colorb[irrep ^ all_buf_irrep][rs][1];
                    bufrs = Buf->params->colidx[r][s];

                    value = Buf->matrix[irrep][bufpq][bufrs];

                    /* Assign the value */
                    Buf->file.matrix[irrep][filerow][rs] = value;
                }

                /* Write out the row */
                file4_mat_irrep_row_wrt(&(Buf->file), irrep, pq);
            }

            /* Close the input buffer */
            file4_mat_irrep_row_close(&(Buf->file), irrep);

            break;
        case 42: /* Pack pq; unpack rs */
            printf("\n\tHaven't programmed method 42 yet!\n");
            exit(PSI_RETURN_FAILURE);

            break;
        case 43: /* Unpack pq; pack rs */
            printf("\n\tHaven't programmed method 43 yet!\n");
            exit(PSI_RETURN_FAILURE);

            break;
        case 45: /* Unpack pq and rs */
            /* I'm not sure if I'll ever need this, so I'm removing it for now */
            printf("\n\tShould you be using method %d?\n", method);
            exit(PSI_RETURN_FAILURE);
            /* Prepare the output buffer for the output DPD file */
            file4_mat_irrep_row_init(&(Buf->file), irrep);

            /* Loop over rows in the dpdfile */
            for (pq = 0; pq < rowtot; pq++) {
                p = Buf->file.params->roworb[irrep][pq][0];
                q = Buf->file.params->roworb[irrep][pq][1];
                bufpq = Buf->params->rowidx[p][q];

                filerow = Buf->file.incore ? pq : 0;

                /* Loop over the columns in the dpdfile */
                for (rs = 0; rs < coltot; rs++) {
                    r = Buf->file.params->colorb[irrep ^ all_buf_irrep][rs][0];
                    s = Buf->file.params->colorb[irrep ^ all_buf_irrep][rs][1];
                    bufrs = Buf->params->colidx[r][s];

                    value = Buf->matrix[irrep][bufpq][bufrs];

                    /* Assign the value */
                    Buf->file.matrix[irrep][filerow][rs] = value;
                }

                /* Write out the row */
                file4_mat_irrep_row_wrt(&(Buf->file), irrep, pq);
            }

            /* Close the input buffer */
            file4_mat_irrep_row_close(&(Buf->file), irrep);

            break;
        default: /* Error trapping */
            printf("\n\tInvalid switch case in dpd_buf_mat_irrep_rd!\n");
            exit(PSI_RETURN_FAILURE);
            break;
    }

    return 0;
}

}  // namespace psi
