<?php

declare(strict_types=1);

/** 
 * @author Robert Strutts <Robert@TryingToScale.com>
 * @copyright Copyright (c) 2022, Robert Strutts.
 * @license MIT
 */

namespace tts\database;

final class dummy_data {

  private $pdo;
  private $random_engine;
 
  public function __construct($pdo) {
    $this->pdo = $pdo;
    $this->random_engine = new \tts\random_engine();
  }

  /*
   * Helper for add_dummy_data and get_dummy_data.
   * Purpose: To return ONE ROW of junk/dummy data from input data.
   * @param array $data
   * @retval array of random dummy data AKA one row worth of it.
   */

  private function use_dummy_data(array $data): array {
    $ret = [];
    foreach ($data as $field => $array_values) {
      $array_count = \bs_tts\common::get_count($array_values);
      if ($array_count) {
        $ret[$field] = $array_values[$this->random_engine->get_int(0, $array_count - 1)];
      }
    }
    return $ret;
  }

  /**
   * Inserts Dummy Data to DB
   * @param int $num_rows to add/make
   * @param array $data sample data EX: array('fname'=>array('bob','kim','lisa', ect...), ...)
   * @retval bool true
   */
  public function add_dummy_data(string $table, int $num_rows, array $data): bool {
    for ($i = 0; $i < $num_rows; $i++) {
      $bind_data = $this->use_dummy_data($data);
      $fields = [];
      foreach ($data as $field => $array_values) {
        $fields[] = $field;
      }
      
      $sql = "INSERT INTO `{$table}` "
          . "(" . implode(", ", $fields) . ") "
          . "VALUES (:" . implode(", :", $fields) . ");";
      
      $bind = [];
      foreach ($fields as $field) {
        $bind[":$field"] = $bind_data[$field];
      }
      unset($bind_data);
      unset($fields);

      $pdo_stmt = $this->pdo->prepare($sql);
      $exec = $pdo_stmt->execute($bind);
      unset($bind);
    }
    return true;
  }

  /**
   * Make an array of fields for a fake row of dummy data out of input data.
   * @param int $num_rows to make
   * @param array $data sample data
   * @retval array of rows with dummy data in it.
   */
  public function get_dummy_data(int $num_rows, array $data): array {
    if ($num_rows > 100) {
        throw new \LengthException("Generating too much dummy data via \$num_rows!");
    }
    $ret = [];
    for ($i = 0; $i < $num_rows; $i++) {
      $ret[] = $this->use_dummy_data($data);
    }
    return $ret;
  }
  
  public function get_dummy_data_generator(
      int $num_rows, 
      array $data
  ): \Generator {
    for ($i = 0; $i < $num_rows; $i++) {
      yield $this->use_dummy_data($data);
    }
  }  
  

}