<?php
namespace Xxx\Tests\Support;

/*
 * A stand-in for mysqli. open_db() makes one when the global $db_class
 * names this class. All connections share the static state below, so a
 * test sees the queries of every connection that the code opened.
 *
 * Handlers answer queries: FakeDb::on('/pattern/', $answer), where the
 * answer is a list of rows, TRUE, FALSE (a failed query) or a function
 * that takes ($sql, $params) and returns one of these. The handler added
 * last wins. A query that no handler matches gets no rows (SELECT) or
 * TRUE (anything else).
 */
class FakeDb {
  public static array $log = array();
  public static array $handlers = array();
  public static array $connections = array();
  public static ?string $connectError = NULL;
  // When set, every query is also appended to this file as a JSON line
  public static ?string $logFile = NULL;

  public $connect_error = NULL;
  public $connect_errno = 0;
  public $error = '';
  public bool $closed = FALSE;

  public static function reset(): void {
    self::$log = array();
    self::$handlers = array();
    self::$connections = array();
    self::$connectError = NULL;
    self::$logFile = NULL;
  }

  public static function on(string $pattern, $answer): void {
    self::$handlers[] = array($pattern, $answer);
  }

  // The SQL of every query so far
  public static function queries(): array {
    return array_column(self::$log, 'sql');
  }

  // The queries whose SQL matches $pattern, each as array('sql' => ..., 'params' => ...)
  public static function matching(string $pattern): array {
    return array_values(array_filter(self::$log, function ($entry) use ($pattern) {
      return preg_match($pattern, $entry['sql']);
    }));
  }

  public function __construct(...$args) {
    self::$connections[] = $args;
    if (self::$connectError !== NULL) {
      $this->connect_errno = 1045;
      $this->connect_error = self::$connectError;
    }
  }

  public function real_escape_string($string) {
    return addslashes((string)$string);
  }

  public function execute_query($sql, $params = array()) {
    if (substr_count($sql, '?') !== count($params))
      throw new \LogicException("Placeholder count does not match the parameters: $sql");
    return $this->run($sql, array_values($params));
  }

  public function query($sql) {
    return $this->run($sql, array());
  }

  public function close() {
    $this->closed = TRUE;
    return TRUE;
  }

  private function run(string $sql, array $params) {
    $entry = array('sql' => $sql, 'params' => $params);
    self::$log[] = $entry;
    if (self::$logFile !== NULL)
      file_put_contents(self::$logFile, json_encode($entry) . "\n", FILE_APPEND | LOCK_EX);

    $answer = NULL;
    foreach (array_reverse(self::$handlers) as list($pattern, $handler)) {
      if (preg_match($pattern, $sql)) {
        $answer = is_callable($handler) ? $handler($sql, $params) : $handler;
        break;
      }
    }
    if ($answer === NULL)
      $answer = preg_match('/^\s*SELECT/i', $sql) ? array() : TRUE;
    if ($answer === FALSE) {
      $this->error = 'Fake failure for: ' . $sql;
      return FALSE;
    }
    return is_array($answer) ? new FakeResult($answer) : $answer;
  }
}