final public static function create()

in src/ColoredUnifiedDiff.php [69:143]

• 65 lines of code
• 13 McCabe index (conditional complexity)

  final public static function create(
    string $a,
    string $b,
    int $context = 3,
  ): TOut {
    $diff = StringDiff::lines($a, $b)->getUnifiedDiff($context);

    $out = vec[];
    $lines = Str\split($diff, "\n");
    while (!C\is_empty($lines)) {
      $line = C\firstx($lines);
      $lines = Vec\drop($lines, 1);

      if ($line === '') {
        invariant(C\is_empty($lines), 'Blank line was not last line');
        break;
      }
      if ($line[0] === '@') {
        $out[] = static::colorHeaderLine($line);
        continue;
      }
      if ($line[0] === ' ') {
        $out[] = static::colorKeepLine($line);
        continue;
      }
      if ($line[0] === '+') {
        $out[] = static::colorInsertLine($line);
        continue;
      }
      if ($line[0] === '-') {
        $next = C\first($lines);
        if (
          $next !== null && $next !== '' && $next[0] === '+'
          // Levenshtein function throws for strings with length > 255
          // Don't need intra word diffs for long lines
          && Str\length($line) < 256 && Str\length($next) < 256
          // -2 to deal with the prefix
          /* HH_FIXME[4107] using directly because this is open source */
          /* HH_FIXME[2049] using directly because this is open source */
          && \levenshtein($line, $next) - 2 <= (0.5 * (Str\length($line) - 2))
        ) {
          // Drop the prefix
          $line = Str\slice($line, 1);
          $next = Str\slice($next, 1);
          $lines = Vec\drop($lines, 1);

          $words_line = vec(\preg_split(
            '/([^a-zA-Z0-9_]+)/',
            $line,
            -1,
            \PREG_SPLIT_DELIM_CAPTURE,
          ));
          $words_next = vec(\preg_split(
            '/([^a-zA-Z0-9_]+)/',
            $next,
            -1,
            \PREG_SPLIT_DELIM_CAPTURE,
          ));
          $intraline = (new StringDiff($words_line, $words_next))->getDiff();
          $out[] = $intraline
            |> Vec\filter($$, $op ==> !$op->isInsertOp())
            |> static::colorDeleteLineWithIntralineEdits($$);
          $out[] = $intraline
            |> Vec\filter($$, $op ==> !$op->isDeleteOp())
            |> static::colorInsertLineWithIntralineEdits($$);
          continue;
        }
        $out[] = static::colorDeleteLine($line);
        continue;
      }
      invariant_violation('unhandled line prefix: %s', $line[0]);
    }

    return static::join($out);
  }