/**
 * \file index.c
 *
 * \brief Low level SQLite database index functions.
 *
 * 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
 * \author Support for multiple connections by Markus Metz
 *
 * \date 2005-2011
 */

#include <grass/dbmi.h>
#include <grass/glocale.h>
#include "globals.h"
#include "proto.h"

/**
 * \fn int db__driver_create_index (dbIndex *index)
 *
 * \brief Create SQLite database index.
 *
 * \param[in] index index to be created
 * \return int DB_FAILED on error; DB_OK on success
 */

int db__driver_create_index(dbIndex *index)
{
    int i, ncols;
    sqlite3_stmt *statement;
    dbString sql;
    const char *rest;
    int ret;

    G_debug(3, "db__create_index()");

    db_init_string(&sql);

    ncols = db_get_index_number_of_columns(index);

    db_set_string(&sql, "create");
    if (db_test_index_type_unique(index))
        db_append_string(&sql, " unique");

    db_append_string(&sql, " index ");
    db_append_string(&sql, "if not exists ");
    db_append_string(&sql, db_get_index_name(index));
    db_append_string(&sql, " on ");

    db_append_string(&sql, db_get_index_table_name(index));

    db_append_string(&sql, " ( ");

    for (i = 0; i < ncols; i++) {
        if (i > 0)
            db_append_string(&sql, ", ");

        db_append_string(&sql, db_get_index_column_name(index, i));
    }

    db_append_string(&sql, " )");

    G_debug(3, " SQL: %s", db_get_string(&sql));

    /* SQLITE bug?
     * If the database schema has changed, sqlite can prepare a statement,
     * but sqlite can not step, the statement needs to be prepared anew again */
    while (1) {
        ret =
            sqlite3_prepare(sqlite, db_get_string(&sql), -1, &statement, &rest);

        if (ret != SQLITE_OK) {
            db_d_append_error("%s\n%s\n%s", _("Unable to create index:"),
                              db_get_string(&sql),
                              (char *)sqlite3_errmsg(sqlite));
            db_d_report_error();
            sqlite3_finalize(statement);
            db_free_string(&sql);
            return DB_FAILED;
        }

        ret = sqlite3_step(statement);
        /* get real result code */
        ret = sqlite3_reset(statement);

        if (ret == SQLITE_SCHEMA) {
            sqlite3_finalize(statement);
            /* try again */
        }
        else if (ret != SQLITE_OK) {
            db_d_append_error("%s\n%s", _("Error in sqlite3_step():"),
                              (char *)sqlite3_errmsg(sqlite));
            db_d_report_error();
            sqlite3_finalize(statement);
            db_free_string(&sql);
            return DB_FAILED;
        }
        else
            break;
    }

    sqlite3_finalize(statement);
    db_free_string(&sql);

    return DB_OK;
}
