<?php

abstract class PhabricatorApplicationTransactionDetailView
  extends AphrontView {
    protected $oldText;
    protected $newText;

    public function setNewText($new_text) {
      $this->newText = $new_text;
      return $this;
    }

    public function setOldText($old_text) {
      $this->oldText = $old_text;
      return $this;
    }

    public function renderForMail() {
      $diff = $this->buildDiff();

      $viewer = $this->getViewer();
      $old_bright = $viewer->getCSSValue('old-bright');
      $new_bright = $viewer->getCSSValue('new-bright');

      $old_styles = array(
        'padding: 0 2px;',
        'color: #333333;',
        "background: {$old_bright};",
      );
      $old_styles = implode(' ', $old_styles);

      $new_styles = array(
        'padding: 0 2px;',
        'color: #333333;',
        "background: {$new_bright};",
      );
      $new_styles = implode(' ', $new_styles);

      $omit_styles = array(
        'padding: 8px 0;',
      );
      $omit_styles = implode(' ', $omit_styles);

      $result = array();
      foreach ($diff->getSummaryParts() as $part) {
        $type = $part['type'];
        $text = $part['text'];
        switch ($type) {
          case '.':
            $result[] = phutil_tag(
              'div',
              array(
                'style' => $omit_styles,
              ),
              pht('...'));
            break;
          case '-':
            $result[] = phutil_tag(
              'span',
              array(
                'style' => $old_styles,
              ),
              $text);
            break;
          case '+':
            $result[] = phutil_tag(
              'span',
              array(
                'style' => $new_styles,
              ),
              $text);
            break;
          case '=':
            $result[] = $text;
            break;
        }
      }

      $styles = array(
        'white-space: pre-wrap;',
        'color: #74777D;',
      );

      // Beyond applying "pre-wrap", convert newlines to "<br />" explicitly
      // to improve behavior in clients like Airmail.
      $result = phutil_escape_html_newlines($result);

      return phutil_tag(
        'div',
        array(
          'style' => implode(' ', $styles),
        ),
        $result);
    }

    public function render() {
      $diff = $this->buildDiff();

      require_celerity_resource('differential-changeset-view-css');

      $result = array();
      foreach ($diff->getParts() as $part) {
        $type = $part['type'];
        $text = $part['text'];
        switch ($type) {
          case '-':
            $result[] = phutil_tag(
              'span',
              array(
                'class' => 'old',
              ),
              $text);
            break;
          case '+':
            $result[] = phutil_tag(
              'span',
              array(
                'class' => 'new',
              ),
              $text);
            break;
          case '=':
            $result[] = $text;
            break;
        }
      }

      $diff_view = phutil_tag(
        'div',
        array(
          'class' => 'prose-diff',
        ),
        $result);

      $old_view = phutil_tag(
        'div',
        array(
          'class' => 'prose-diff',
        ),
        $this->oldText);

      $new_view = phutil_tag(
        'div',
        array(
          'class' => 'prose-diff',
        ),
        $this->newText);

      return id(new PHUITabGroupView())
        ->addTab(
          id(new PHUITabView())
            ->setKey('old')
            ->setName(pht('Old'))
            ->appendChild($old_view))
        ->addTab(
          id(new PHUITabView())
            ->setKey('new')
            ->setName(pht('New'))
            ->appendChild($new_view))
        ->addTab(
          id(new PHUITabView())
            ->setKey('diff')
            ->setName(pht('Diff'))
            ->appendChild($diff_view))
        ->selectTab('diff');
    }

    private function buildDiff() {
      $engine = new PhutilProseDifferenceEngine();
      return $engine->getDiff($this->oldText, $this->newText);
    }
}