private static function getExampleBlock()

in src/markdown-extensions/ExampleIncludeBlock.php [77:155]
60 lines of code
5 McCabe index (conditional complexity)

  private static function getExampleBlock(string $file): UnparsedBlocks\Block {
    $code = \file_get_contents($file);

    $start_pos = Str\search($code, self::START_MARKER);
    if ($start_pos is nonnull) {
      // Actual start should be the next line after the marker.
      $start_pos = Str\search($code, "\n", $start_pos) as nonnull;
      $code = Str\slice($code, $start_pos + 1);

      invariant(
        !Str\contains($code, self::START_MARKER),
        '%s contains multiple %s',
        $file,
        self::START_MARKER,
      );

      $end_pos = Str\search($code, self::END_MARKER);
      if ($end_pos is nonnull) {
        $code = Str\slice($code, 0, $end_pos);
        // Actual end should be the end of the previous line before the marker.
        $end_pos = Str\search_last($code, "\n") as nonnull;
        $code = Str\slice($code, 0, $end_pos + 1);
      }
    } else {
      // No explicit start marker, use magic.

      // First, strip initial boilerplate lines (<?hh/namespace/use/empty).
      $code = Regex\replace(
        $code,
        re"/^( *(<\\?hh.*|namespace .+;|use namespace HH\\\\.+;|)\n)+/",
        '',
      );

      // If the remaining code is a single <<__EntryPoint>> function, extract
      // its body.
      $match = Regex\first_match(
        $code,
        re"/^
          \\s*
          <<__EntryPoint>>
          \\s*
          function \\s+ [_a-zA-Z0-9]+\\(\\): \\s* void \\s* { \\n
            (?<body>
              # one or more indented or empty lines
              (\\ \\ .*\\n|\\n)+
            )
          }
          \\s*
        $/x",
      );

      if ($match is nonnull) {
        $code = $match['body'];
      }
    }

    invariant(
      !Str\contains($code, self::END_MARKER),
      '%s contains %s without a matching %s',
      $file,
      self::END_MARKER,
      self::START_MARKER,
    );

    // If all (non-empty) lines are indented (usually happens if we extracted a
    // function body above), find the minimum indentation and unindent by that
    // amount.
    if (!Regex\matches($code, re"/^[^ \n]/m")) {
      $code = Regex\every_match($code, re"/^ +/m")
        |> Keyset\map($$, $match ==> $match[0])
        |> Keyset\sort($$)
        |> C\firstx($$)
        |> Str\replace($code, "\n".$$, "\n");
    }

    $code = Regex\replace($code, re"/ *\\\\init_docs_autoloader\\(\\);\n/", '');

    return new UnparsedBlocks\FencedCodeBlock(Str\trim($code), 'Hack');
  }