/*
 * @project      The CERN Tape Archive (CTA)
 * @copyright    Copyright © 2021-2022 CERN
 * @license      This program is free software, distributed under the terms of the GNU General Public
 *               Licence version 3 (GPL Version 3), copied verbatim in the file "COPYING". You can
 *               redistribute it and/or modify it under the terms of the GPL Version 3, or (at your
 *               option) any later version.
 *
 *               This program 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.
 *
 *               In applying this licence, CERN does not waive the privileges and immunities
 *               granted to it by virtue of its status as an Intergovernmental Organization or
 *               submit itself to any jurisdiction.
 */

#include <iostream>
#include <regex>

#include "DbToSQLiteStatementTransformer.hpp"
#include "common/utils/Regex.hpp"
#include "common/utils/utils.hpp"


namespace cta::catalogue {

/*****************************************************/
/* CreateGlobalTempTableToSQLiteStatementTransformer */
/*****************************************************/
CreateGlobalTempTableToSQLiteStatementTransformer::CreateGlobalTempTableToSQLiteStatementTransformer(const std::string &statement):DbToSQLiteStatementTransformer(statement){}

std::string CreateGlobalTempTableToSQLiteStatementTransformer::transform(){
  utils::searchAndReplace(m_statement,"GLOBAL TEMPORARY","TEMPORARY");
  utils::searchAndReplace(m_statement,"ON COMMIT DELETE ROWS;",";");
  return m_statement;
}
/*****************************************************/
/* CreateGlobalTempTableToSQLiteStatementTransformer */
/*****************************************************/

/*****************************/
/* IndexStatementTransformer */
/*****************************/
IndexStatementTransformer::IndexStatementTransformer(const std::string& statement):DbToSQLiteStatementTransformer(statement){}

std::string IndexStatementTransformer::transform(){
  utils::searchAndReplace(m_statement,"UNIQUE "," ");
  // This is a bit crude, but it will work so long as we don't have indexes with multiple nested functions...
  std::regex lowerRegex("LOWER\\(([^\\)]*)\\)");
  m_statement = std::regex_replace(m_statement, lowerRegex, "\\1", std::regex_constants::format_sed);
  return m_statement;
}
/*****************************/
/* IndexStatementTransformer */
/*****************************/

/**********************************/
/* DeleteStatementTransformer     */
/**********************************/
DeleteStatementTransformer::DeleteStatementTransformer(const std::string& statement):DbToSQLiteStatementTransformer(statement){}

std::string DeleteStatementTransformer::transform(){
  return "";
}
/**********************************/
/* DeleteStatementTransformer     */
/**********************************/

/*****************************************************/
/* DbToSQLiteStatementTransformerFactory             */
/*****************************************************/
std::unique_ptr<DbToSQLiteStatementTransformer> DbToSQLiteStatementTransformerFactory::create(const std::string &statement){
  StatementType stmtType = statementToStatementType(statement);
  std::unique_ptr<DbToSQLiteStatementTransformer> ret;
  switch(stmtType){
    case StatementType::CREATE_GLOBAL_TEMPORARY_TABLE:
      ret.reset(new CreateGlobalTempTableToSQLiteStatementTransformer(statement));
      break;
    case StatementType::CREATE_INDEX:
      ret.reset(new IndexStatementTransformer(statement));
      break;
    case StatementType::CREATE_SEQUENCE://CREATE SEQUENCE is not SQLite compatible, we delete this statement
    case StatementType::SKIP:
      ret.reset(new DeleteStatementTransformer(statement));
      break;
    default:
      //CREATE TABLE, INSERT INTO CTA_VERSION, OTHERS
      //If the statement does not need modification, we return it as it is
      ret.reset(new DbToSQLiteStatementTransformer(statement));
      break;
  }
  return ret;
}

const std::map<std::string,DbToSQLiteStatementTransformerFactory::StatementType> DbToSQLiteStatementTransformerFactory::regexToStatementMap = DbToSQLiteStatementTransformerFactory::initializeRegexToStatementMap();

DbToSQLiteStatementTransformerFactory::StatementType DbToSQLiteStatementTransformerFactory::statementToStatementType(const std::string &statement){
  for(auto &kv: regexToStatementMap){
    utils::Regex regexToTest(kv.first);
    if(regexToTest.exec(statement).size() != 0){
      return kv.second;
    }
  }
  return StatementType::SKIP;
}

std::map<std::string,DbToSQLiteStatementTransformerFactory::StatementType> DbToSQLiteStatementTransformerFactory::initializeRegexToStatementMap()
{
  std::map<std::string,StatementType> ret;
  ret["CREATE TABLE ([a-zA-Z_]+)"] = StatementType::CREATE_TABLE;
  ret["CREATE (UNIQUE )?INDEX ([a-zA-Z_]+)"] = StatementType::CREATE_INDEX;
  ret["CREATE GLOBAL TEMPORARY TABLE ([a-zA-Z_]+)"] = StatementType::CREATE_GLOBAL_TEMPORARY_TABLE;
  ret["CREATE SEQUENCE ([a-zA-Z_]+)"] = StatementType::CREATE_SEQUENCE;
  ret["INSERT INTO CTA_CATALOGUE([a-zA-Z_]+)"] = StatementType::INSERT_INTO_CTA_VERSION;
  ret["INSERT INTO ([a-zA-Z_]+)"] = StatementType::SKIP;
  return ret;
}
/*****************************************************/
/* DbToSQLiteStatementTransformerFactory             */
/*****************************************************/

} // namespace cta::catalogue