<?php

namespace Tenweb_Manager {

  class MigrationDB extends Migration
  {

      private $password;
      private $iv;


      public function __construct($password,$iv)
      {
          parent::__construct();

          $this->password = $password;
          $this->iv = $iv;

      }

    /**
     * @return bool
     * @throws \Exception
     */
    public function run()
    {
      // get tables
      $tables = $this->get_tables();

      $file_to_save_database_data = self::get_tmp_dir() . "/" . self::MIGRATION_DB_FILE_NAME;
      //open sql file
      if (($db_file = fopen($file_to_save_database_data, "w+")) !== false) {
        // add sql headers
        $sql_header_string = "SET SQL_MODE = \"NO_AUTO_VALUE_ON_ZERO\";" . PHP_EOL . "SET time_zone = \"+00:00\";" . PHP_EOL . "SET foreign_key_checks = 0;" . PHP_EOL;

        $this->add_to_file($db_file, $sql_header_string . PHP_EOL);
        foreach ($tables as $table) {
          // get create table syntax
          if (($create_table = $this->get_create_table_str($table)) !== false) {
            // run drop table if table exists
            $drop_string = "DROP TABLE IF EXISTS `{$table}`";
            $this->add_to_file($db_file, $drop_string . ';' . PHP_EOL);
            // run create table
            $this->add_to_file($db_file, $create_table . ';' . PHP_EOL . PHP_EOL);
            // if table has data, run insert data

            $this->insert_data($table, $db_file);

            /*if ($insert_data) {
              $this->add_to_file($db_file, $insert_data . ';' . PHP_EOL . PHP_EOL);
            }*/
          }
        }

        if(!TENWEB_MIGRATION_DEBUG && function_exists('openssl_encrypt')){
          $this->encrypt_db_file($db_file, $file_to_save_database_data);
        }
        else {
        // after all close file
          fclose($db_file);
        }

        return $file_to_save_database_data;
      } else {
        throw new \Exception("Unable open database sql file");
      }

    }


    /**
     * @param $table_name
     *
     * @return bool|string
     * @throws \Exception
     */
    private function insert_data($table_name, $db_file)
    {
        Helper::store_migration_log('start_insert_data', 'Start insert_data function.');
        // get table rows
        $table_data = $this->wpdb->get_results("SELECT * FROM `{$table_name}`", ARRAY_A);
        $columns = $this->get_table_structure($table_name);
        if (!empty($table_data)) {
            // generate insertion string
            $insert_rows = array();

            $insert_data = "INSERT INTO `{$table_name}` (" . implode(",", $this->get_table_columns($columns)) . ") VALUES ";

            $i = 0;
            $j = 1;
            $current_insert_data = $insert_data;

            foreach ($table_data as $table_row) {

                $insert_values = array();
                foreach ($table_row as $field_name => $field_value) {
                    if (empty($field_value)) {
                        if ($columns[$field_name]["Null"] != "NO") {
                            $insert_values[$field_name] = 'NULL';
                        } else {
                            if (strpos(strtolower($columns[$field_name]["Type"]), "int") !== false || $field_value === '0' ) {
                                $insert_values[$field_name] = '0';
                            } else {
                                $insert_values[$field_name] = "''";
                            }
                        }
                    } else {
                        $insert_values[$field_name] = "'" . addslashes($field_value) . "'";
                    }
                }

                $current_insert_data .= "(" . implode(",", array_values($insert_values)) . "),";

                $i++;

                if ($i == 500) {
                    Helper::store_migration_log('row_limit_' . $j, 'Rows limit reached, adding to file.');
                    $current_insert_data = rtrim($current_insert_data, ",");
                    $this->add_to_file($db_file, $current_insert_data . ';' . PHP_EOL . PHP_EOL);
                    $i = 0;
                    $j++;
                    $current_insert_data = $insert_data;
                }

                //array_push($insert_rows, $insert_values);
            }

            if ($i > 0) {
                Helper::store_migration_log('rows_remain', 'Rows reamain, adding to file.');
                $current_insert_data = rtrim($current_insert_data, ",");
                $this->add_to_file($db_file, $current_insert_data . ';' . PHP_EOL . PHP_EOL);
            }

            /*if (count($table_data) > 0) {
                $insert_data = rtrim($insert_data, ",");
                return $insert_data;
            }*/

            //return false;
        }

        Helper::store_migration_log('end_insert_data', 'End insert_data function.');
    }

    /**
     * @param $table_structure
     *
     * @return array
     */
    private function get_table_columns($table_structure)
    {
      $columns = array_keys($table_structure);
      $columns = array_map(function ($value) {
        return "`" . $value . "`";
      }, $columns);

      return $columns;
    }

    /**
     * @param $table_name
     *
     * @return array
     */
    private function get_table_structure($table_name)
    {
      $table_columns = array();
      $table_structure = $this->wpdb->get_results("DESCRIBE `{$table_name}`", ARRAY_A);

      foreach ($table_structure as $column) {
        $table_columns[$column["Field"]] = $column;
      }

      return $table_columns;
    }

    /**
     * @param $table_name
     *
     * @return mixed
     */
    private function get_create_table_str($table_name)
    {
      // get create table syntax
      $create_table = $this->wpdb->get_row("SHOW CREATE TABLE `{$table_name}`", ARRAY_N);

      return !empty($create_table[1]) ? $create_table[1] : false;
    }

    /**
     * @return array
     */
    private function get_tables()
    {
      Helper::store_migration_log('start_get_tables', 'Start get_tables function.');
      $tables = array();
      $data = $this->wpdb->get_results("SHOW TABLES FROM `{$this->wpdb->dbname}`");
      if (!empty($data)) {
        $key = 'Tables_in_' . $this->wpdb->dbname;
        foreach ($data as $table) {
          if (strpos($table->$key, $this->wpdb->prefix) === 0) {
            array_push($tables, $table->$key);
          }
        }
      }

      Helper::store_migration_log('end_get_tables', 'End get_tables function.');

      return $tables;
    }

    /**
     * @param $file
     * @param $data
     *
     * @throws \Exception
     */
    private function add_to_file($file, $data)
    {
      if (fwrite($file, $data) === false) {
        throw new \Exception("Unable write data to db file");
      }
    }


      private function encrypt_db_file($file, $db_file_path)
      {
          $dest = tempnam(self::get_tmp_dir(),'db');

          $key = $this->password;
          //initialization vector
          $iv = $this->iv;
          fseek($file,0);
          $error = false;
          if ($fpOut = fopen($dest, 'w')) {
                  while (!feof($file)) {
                      $plaintext = fread($file, 16 * 1000);
                      $ciphertext = openssl_encrypt($plaintext, 'AES-256-CBC', $key, null, $iv);
                      //$iv = substr($ciphertext, 0, 16);
                      fwrite($fpOut, $ciphertext);
                  }
              fclose($fpOut);
          } else {
              $error = true;
          }

          unlink($db_file_path);
          rename($dest, $db_file_path);

          return $error ? false : true;
      }
  }
}