/*
  Copyright 2011 Grégory Soutadé

  This file is part of KissCount.

  KissCount is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  KissCount 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 General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with KissCount.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <iostream>
#include <QString>
#include <QMessageBox>
#include <QSqlQuery>
#include <QSqlError>
#include <QVariant>
#include <QSqlRecord>

#include "Database.hpp"

#define ON_ERROR(m)				\
    QMessageBox::critical(0, _("Error"), m);	\
    throw m;

typedef void (*update_func)(QSqlDatabase& _db) ;

#define UPDATE_TABLE(from, to, step) EXECUTE_SQL_UPDATE_WITH_CODE(req, , throw std::string("Error while upgrading from version " from " to version " to ", step " step);, });

static void Version_1_to_2(QSqlDatabase& _db)
{
    QString req ;

    /* Category */
    req = "ALTER TABLE category ADD fix_cost CHAR(1)";

    UPDATE_TABLE("1", "2", "1");

    req = "UPDATE category SET fix_cost='0'";

    UPDATE_TABLE("1", "2", "2");

    req = "UPDATE category SET fix_cost='1' WHERE id IN (";
    req += "SELECT MIN(category.id) FROM category, user WHERE category.user = user.id";
    req += ")";

    UPDATE_TABLE("1", "2", "3");

    /* Account */
    req = "ALTER TABLE account ADD virtual CHAR(1)";

    UPDATE_TABLE("1", "2", "4");

    req = "UPDATE account SET virtual='0'";

    UPDATE_TABLE("1", "2", "5");

    /* Operation */
    req = "ALTER TABLE operation ADD virtual CHAR(1)";

    UPDATE_TABLE("1", "2", "6");

    req = "UPDATE operation SET virtual='0'";

    UPDATE_TABLE("1", "2", "7");    

    /* Import Pattern */
    req = "CREATE TABLE import_pattern(id INTEGER PRIMARY KEY, user REFERENCES user(id), description VARCHAR(255), pattern VARCHAR(255), account REFERENCES account(id), category REFERENCES category(id))";

    UPDATE_TABLE("1", "2", "8");    
}

static update_func updates[] = {
    Version_1_to_2
};

void Database::CheckDatabaseVersion()
{
    QString req ;
    QSqlRecord set ;
    QSqlQuery query(_db);
    long int version;
    int i;

    req = "SELECT db_version FROM kisscount";

    EXECUTE_SQL_QUERY_WITH_CODE(req, , ON_ERROR("Unable to get database version"), {});

    query.next();
    
    set = query.record();

    if (!(version = set.value("db_version").toInt()))
    {
	ON_ERROR("Invalid database version");
    }

    if (version == Database::VERSION) return;

    if (version > Database::VERSION)
    {
	ON_ERROR("Your current version of KissCount is too old and can't load this database. Please upgrade KissCount");	
    }

    version--;

    // Maybe one update is impossible
    for(i=version; i<Database::VERSION-1; i++)
    {
	if (!updates[i])
	{
	    ON_ERROR("The database cannot be upgraded. Please use an older version of KissCount");	
	}
    }

    if (QMessageBox::question(0, "KissCount", "You use an old database model. KissCount will try to upgrade it to the lastest version")
	== QMessageBox::No)
	throw std::string("can't load this database");

    _db.transaction();

    try
    {
	for(i=version; i<Database::VERSION-1; i++)
	{
	    updates[i](_db);
	}
 
	req = "UPDATE kisscount SET db_version='" + QString::number(Database::VERSION) + "'";

	EXECUTE_SQL_UPDATE_WITH_CODE(req, , throw std::string("Unable to set new database version"), {});
    }
    catch (std::string e)
    {
	std::cout << e << std::endl;

	_db.rollback();
	
	throw e;
    }

    _db.commit();

    QMessageBox::information(0, "KissCount", "Database upgrade successful !");
}