<?php

final class PhutilRemarkupInterpreterBlockRule extends PhutilRemarkupBlockRule {

  /**
   * Second part of the regex to find stuff like:
   *     interpreterName {{{ stuff }}}
   *     interpreterName (options) {{{ stuff }}}
   * You have found the kernel of cowsay and figlet.
   */
  const END_BLOCK_PATTERN   = '/}}}\s*$/';

  /**
   * Constructs the first part of the regex to find stuff like:
   *     interpreterName {{{ stuff }}}
   *     interpreterName (options) {{{ stuff }}}
   * The exact regex is constructed from the available interpreters.
   * @return string First part of interpreters regex
   */
  private function getStartBlockPattern() {
    $interpreters = id(new PhutilClassMapQuery())
      ->setAncestorClass(PhutilRemarkupBlockInterpreter::class)
      ->execute();
    $interpreters_regex = mpull($interpreters, 'getInterpreterName');
    $interpreters_regex = array_map('preg_quote', $interpreters_regex);
    $interpreters_regex = implode('|', $interpreters_regex);
    return "/^($interpreters_regex)\s*(?:\(([^)]+)\)\s*)?{{{/";
  }

  public function getMatchingLineCount(array $lines, $cursor) {
    $num_lines = 0;

    if (preg_match(self::getStartBlockPattern(), $lines[$cursor])) {
      $num_lines++;

      while (isset($lines[$cursor])) {
        if (preg_match(self::END_BLOCK_PATTERN, $lines[$cursor])) {
          break;
        }
        $num_lines++;
        $cursor++;
      }
    }

    return $num_lines;
  }

  public function markupText($text, $children) {
    $lines = explode("\n", $text);
    $first_key = head_key($lines);
    $last_key = last_key($lines);
    while (trim($lines[$last_key]) === '') {
      unset($lines[$last_key]);
      $last_key = last_key($lines);
    }
    $matches = null;

    preg_match(self::getStartBlockPattern(), head($lines), $matches);

    $argv = array();
    if (isset($matches[2])) {
      $argv = id(new PhutilSimpleOptions())->parse($matches[2]);
    }

    $interpreters = id(new PhutilClassMapQuery())
      ->setAncestorClass(PhutilRemarkupBlockInterpreter::class)
      ->execute();

    foreach ($interpreters as $interpreter) {
      $interpreter->setEngine($this->getEngine());
    }

    $lines[$first_key] = preg_replace(
      self::getStartBlockPattern(),
      '',
      $lines[$first_key]);
    $lines[$last_key] = preg_replace(
      self::END_BLOCK_PATTERN,
      '',
      $lines[$last_key]);

    if (trim($lines[$first_key]) === '') {
      unset($lines[$first_key]);
    }
    if (trim($lines[$last_key]) === '') {
      unset($lines[$last_key]);
    }

    $content = implode("\n", $lines);

    $interpreters = mpull($interpreters, null, 'getInterpreterName');

    if (isset($interpreters[$matches[1]])) {
      return $interpreters[$matches[1]]->markupContent($content, $argv);
    }

    $message = pht('No interpreter found: %s', $matches[1]);

    if ($this->getEngine()->isTextMode()) {
      return '('.$message.')';
    }

    return phutil_tag(
      'div',
      array(
        'class' => 'remarkup-interpreter-error',
      ),
      $message);
  }

}