/*!
   \file db/driver/postgres/listdb.c

   \brief DBMI - Low Level PostgreSQL database driver - list tables

   This program is free software under the GNU General Public License
   (>=v2). Read the file COPYING that comes with GRASS for details.

   \author Radim Blazek
 */
#include <stdlib.h>
#include <string.h>
#include <grass/dbmi.h>
#include <grass/glocale.h>
#include "globals.h"
#include "proto.h"

int db__driver_list_tables(dbString **tlist, int *tcount, int system)
{
    int i, j, nrows, trows, vrows, ncols, tablecol, tschemacol, viewcol,
        vschemacol;
    dbString *list;
    PGresult *rest, *resv;
    char buf[DB_SQL_MAX];

    *tlist = NULL;
    *tcount = 0;

    /* Get table names */
    snprintf(buf, sizeof(buf),
             "SELECT * FROM pg_tables WHERE schemaname %s "
             " ('pg_catalog', 'information_schema') ORDER BY tablename",
             system ? "IN" : "NOT IN");
    G_debug(2, "SQL: %s", buf);

    rest = PQexec(pg_conn, buf);
    if (!rest || PQresultStatus(rest) != PGRES_TUPLES_OK) {
        db_d_append_error("%s\n%s", _("Unable to select table names."),
                          PQerrorMessage(pg_conn));
        db_d_report_error();
        PQclear(rest);
        return DB_FAILED;
    }

    /* Find table and schema col */
    ncols = PQnfields(rest);
    tschemacol = -1;
    for (i = 0; i < ncols; i++) {
        if (strcmp(PQfname(rest, i), "tablename") == 0)
            tablecol = i;

        if (strcmp(PQfname(rest, i), "schemaname") == 0)
            tschemacol = i;
    }

    /* Get view names */
    snprintf(buf, sizeof(buf),
             "SELECT * FROM pg_views WHERE schemaname %s "
             " ('pg_catalog', 'information_schema') ORDER BY viewname",
             system ? "IN" : "NOT IN");
    G_debug(2, "SQL: %s", buf);

    resv = PQexec(pg_conn, buf);
    if (!resv || PQresultStatus(resv) != PGRES_TUPLES_OK) {
        db_d_append_error("%s\n%s", _("Unable to select view names."),
                          PQerrorMessage(pg_conn));
        db_d_report_error();
        PQclear(resv);
        return DB_FAILED;
    }

    /* Find viewname and schema col */
    ncols = PQnfields(resv);
    vschemacol = -1;
    for (i = 0; i < ncols; i++) {
        if (strcmp(PQfname(resv, i), "viewname") == 0)
            viewcol = i;

        if (strcmp(PQfname(resv, i), "schemaname") == 0)
            vschemacol = i;
    }

    trows = PQntuples(rest);
    vrows = PQntuples(resv);
    nrows = trows + vrows;

    list = db_alloc_string_array(nrows);

    if (list == NULL) {
        db_d_append_error(_("Out of memory"));
        db_d_report_error();
        return DB_FAILED;
    }

    for (i = 0; i < trows; i++) {
        if (tschemacol >= 0) {
            snprintf(buf, sizeof(buf), "%s.%s",
                     (char *)PQgetvalue(rest, i, tschemacol),
                     (char *)PQgetvalue(rest, i, tablecol));
        }
        else {
            snprintf(buf, sizeof(buf), "%s",
                     (char *)PQgetvalue(rest, i, tablecol));
        }
        db_set_string(&list[i], buf);
    }

    PQclear(rest);

    for (j = 0; j < vrows; j++) {
        if (vschemacol >= 0) {
            snprintf(buf, sizeof(buf), "%s.%s",
                     (char *)PQgetvalue(resv, j, vschemacol),
                     (char *)PQgetvalue(resv, j, viewcol));
        }
        else {
            snprintf(buf, sizeof(buf), "%s",
                     (char *)PQgetvalue(resv, j, viewcol));
        }
        db_set_string(&list[i], buf);
        i++;
    }

    PQclear(resv);

    *tlist = list;
    *tcount = nrows;
    return DB_OK;
}
