/**********************************************************
 * MODULE:    mysql
 * AUTHOR(S): Radim Blazek (radim.blazek@gmail.com)
 * PURPOSE:   MySQL database driver
 * COPYRIGHT: (C) 2001 by the GRASS Development Team
 *            This program is free software under the
 *            GNU General Public License (>=v2).
 *            Read the file COPYING that comes with GRASS
 *            for details.
 **********************************************************/
#include <grass/gis.h>
#include <grass/dbmi.h>
#include <grass/glocale.h>

#include "globals.h"
#include "proto.h"

int db__driver_describe_table(dbString *table_name, dbTable **table)
{
    dbString sql;
    MYSQL_RES *res;

    db_init_string(&sql);

    db_set_string(&sql, "select * from ");
    db_append_string(&sql, db_get_string(table_name));
    db_append_string(&sql, " where 1 = 0");

    if (mysql_query(connection, db_get_string(&sql)) != 0) {
        db_d_append_error("%s\n%s\n%s", _("Unable to describe table:"),
                          db_get_string(&sql), mysql_error(connection));
        db_d_report_error();
        return DB_FAILED;
    }

    res = mysql_store_result(connection);

    if (res == NULL) {
        db_d_append_error("%s\n%s", db_get_string(&sql),
                          mysql_error(connection));
        db_d_report_error();
        return DB_FAILED;
    }

    if (describe_table(res, table, NULL) == DB_FAILED) {
        db_d_append_error(_("Unable to describe table"));
        db_d_report_error();
        mysql_free_result(res);
        return DB_FAILED;
    }

    mysql_free_result(res);

    db_set_table_name(*table, db_get_string(table_name));

    return DB_OK;
}

/* describe table, if c is not NULL cur->cols and cur->ncols is also set */
int describe_table(MYSQL_RES *res, dbTable **table, cursor *c)
{
    int i, ncols, kcols;
    char *name;
    int sqltype, length;
    dbColumn *column;
    MYSQL_FIELD *fields;

    G_debug(3, "describe_table()");

    ncols = mysql_num_fields(res);
    fields = mysql_fetch_fields(res);

    /* Count columns of known type */
    kcols = 0;
    for (i = 0; i < ncols; i++) {
        field_info(&(fields[i]), &sqltype, &length);

        if (sqltype == DB_SQL_TYPE_UNKNOWN)
            continue;

        kcols++; /* known types */
    }

    G_debug(3, "kcols = %d", kcols);

    if (!(*table = db_alloc_table(kcols))) {
        return DB_FAILED;
    }

    if (c) {
        c->ncols = kcols;
        c->cols = (int *)G_malloc(kcols * sizeof(int));
    }

    db_set_table_name(*table, "");
    db_set_table_description(*table, "");

    /* Currently not used in GRASS */
    /*
       db_set_table_delete_priv_granted (*table);
       db_set_table_insert_priv_granted (*table);
       db_set_table_delete_priv_not_granted (*table);
       db_set_table_insert_priv_not_granted (*table);
     */

    kcols = 0;
    for (i = 0; i < ncols; i++) {
        name = fields[i].name;
        field_info(&(fields[i]), &sqltype, &length);

        G_debug(3, "col: %s, kcols %d, sqltype %d", name, kcols, sqltype);

        G_debug(3, "flags = %d", fields[i].flags);

        if (sqltype == DB_SQL_TYPE_UNKNOWN) {
            /* Print warning and continue */
            G_warning(_("MySQL driver: column '%s', type %d "
                        "is not supported"),
                      name, fields[i].type);
            continue;
        }

        if (fields[i].type == MYSQL_TYPE_LONGLONG)
            G_warning(_("column '%s' : type BIGINT is stored as "
                        "integer (4 bytes) some data may be damaged"),
                      name);

        column = db_get_table_column(*table, kcols);

        db_set_column_name(column, name);
        db_set_column_length(column, length);
        db_set_column_host_type(column, (int)fields[i].type);
        db_set_column_sqltype(column, sqltype);

        db_set_column_precision(column, (int)fields[i].decimals);
        db_set_column_scale(column, 0);

        if (!(fields[i].flags & NOT_NULL_FLAG)) {
            db_set_column_null_allowed(column);
        }
        db_set_column_has_undefined_default_value(column);
        db_unset_column_use_default_value(column);

        /* Currently not used in GRASS */
        /*
           db_set_column_select_priv_granted (column);
           db_set_column_update_priv_granted (column);
           db_set_column_update_priv_not_granted (column);
         */

        if (c) {
            c->cols[kcols] = i;
        }

        kcols++;
    }

    return DB_OK;
}

/* Get sqltype for field */
void field_info(MYSQL_FIELD *field, int *sqltype, int *length)
{
    *length = field->length;

    switch (field->type) {
    case MYSQL_TYPE_TINY:
        *sqltype = DB_SQL_TYPE_SMALLINT;
        break;

    case MYSQL_TYPE_SHORT:
    case MYSQL_TYPE_LONG:
    case MYSQL_TYPE_INT24:
    case MYSQL_TYPE_LONGLONG:
        *sqltype = DB_SQL_TYPE_INTEGER;
        break;

    case MYSQL_TYPE_DECIMAL:
#ifdef MYSQL_TYPE_NEWDECIMAL
    case MYSQL_TYPE_NEWDECIMAL:
#endif
        *sqltype = DB_SQL_TYPE_DECIMAL;
        break;

    case MYSQL_TYPE_FLOAT:
        *sqltype = DB_SQL_TYPE_REAL;
        break;

    case MYSQL_TYPE_DOUBLE:
        *sqltype = DB_SQL_TYPE_DOUBLE_PRECISION;
        break;

    case MYSQL_TYPE_TIMESTAMP:
        *sqltype = DB_SQL_TYPE_TIMESTAMP;
        break;

    case MYSQL_TYPE_DATE:
        *sqltype = DB_SQL_TYPE_DATE;
        break;

    case MYSQL_TYPE_TIME:
        *sqltype = DB_SQL_TYPE_TIME;
        break;

    case MYSQL_TYPE_DATETIME:
        /* *sqltype = DB_SQL_TYPE_DATETIME; */
        /* *sqltype |= DB_DATETIME_MASK; */
        *sqltype = DB_SQL_TYPE_TIMESTAMP;
        break;

    case MYSQL_TYPE_YEAR:
        *sqltype = DB_SQL_TYPE_INTEGER;
        break;

    case MYSQL_TYPE_STRING:
    case MYSQL_TYPE_VAR_STRING:
    case MYSQL_TYPE_SET:
    case MYSQL_TYPE_ENUM:
        *sqltype = DB_SQL_TYPE_CHARACTER;
        break;

    case MYSQL_TYPE_BLOB:
        if (field->flags & BINARY_FLAG) {
            *sqltype = DB_SQL_TYPE_UNKNOWN;
        }
        else {
            *sqltype = DB_SQL_TYPE_TEXT;
        }
        break;

    case MYSQL_TYPE_GEOMETRY:
    case MYSQL_TYPE_NULL:
        *sqltype = DB_SQL_TYPE_UNKNOWN;
        break;

    default:
        *sqltype = DB_SQL_TYPE_UNKNOWN;
    }

    return;
}
