<?php

/*
 * Copyright 2012 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @group phriction
 */
final class PhrictionDiffController
  extends PhrictionController {

  private $id;

  public function willProcessRequest(array $data) {
    $this->id = $data['id'];
  }

  public function processRequest() {

    $request = $this->getRequest();
    $user = $request->getUser();

    $document = id(new PhrictionDocument())->load($this->id);
    if (!$document) {
      return new Aphront404Response();
    }

    $current = id(new PhrictionContent())->load($document->getContentID());

    $l = $request->getInt('l');
    $r = $request->getInt('r');

    $ref = $request->getStr('ref');
    if ($ref) {
      list($l, $r) = explode(',', $ref);
    }

    $content = id(new PhrictionContent())->loadAllWhere(
      'documentID = %d AND version IN (%Ld)',
      $document->getID(),
      array($l, $r));
    $content = mpull($content, null, 'getVersion');

    $content_l = idx($content, $l, null);
    $content_r = idx($content, $r, null);

    if (!$content_l || !$content_r) {
      return new Aphront404Response();
    }

    $text_l = $content_l->getContent();
    $text_r = $content_r->getContent();

    $text_l = wordwrap($text_l, 80);
    $text_r = wordwrap($text_r, 80);


    $engine = new PhabricatorDifferenceEngine();
    $changeset = $engine->generateChangesetFromFileContent($text_l, $text_r);

    $changeset->setOldProperties(
      array(
        'Title'   => $content_l->getTitle(),
      ));
    $changeset->setNewProperties(
      array(
        'Title'   => $content_r->getTitle(),
      ));

    $whitespace_mode = DifferentialChangesetParser::WHITESPACE_SHOW_ALL;

    $parser = new DifferentialChangesetParser();
    $parser->setChangeset($changeset);
    $parser->setRenderingReference("{$l},{$r}");
    $parser->setWhitespaceMode($whitespace_mode);

    $spec = $request->getStr('range');
    list($range_s, $range_e, $mask) =
      DifferentialChangesetParser::parseRangeSpecification($spec);
    $output = $parser->render($range_s, $range_e, $mask);

    if ($request->isAjax()) {
      return id(new AphrontAjaxResponse())->setContent(
        array(
          'changeset' => $output,
        ));
    }

    require_celerity_resource('differential-changeset-view-css');
    require_celerity_resource('syntax-highlighting-css');
    require_celerity_resource('phriction-document-css');

    Javelin::initBehavior('differential-show-more', array(
      'uri'         => '/phriction/diff/'.$document->getID().'/',
      'whitespace'  => $whitespace_mode,
    ));

    $slug = $document->getSlug();

    $revert_l = $this->renderRevertButton($content_l, $current);
    $revert_r = $this->renderRevertButton($content_r, $current);

    $crumbs = new AphrontCrumbsView();
    $crumbs->setCrumbs(
      array(
        'Phriction',
        phutil_render_tag(
          'a',
          array(
            'href' => PhrictionDocument::getSlugURI($slug),
          ),
          phutil_escape_html($current->getTitle())),
        phutil_render_tag(
          'a',
          array(
            'href' => '/phriction/history/'.$document->getSlug().'/',
          ),
          'History'),
        phutil_escape_html("Changes Between Version {$l} and Version {$r}"),
      ));

    $comparison_table = $this->renderComparisonTable(
      array(
        $content_r,
        $content_l,
      ));

    $navigation_table = null;
    if ($l + 1 == $r) {
      $nav_l = ($l > 1);
      $nav_r = ($r != $current->getVersion());

      $uri = $request->getRequestURI();

      if ($nav_l) {
        $link_l = phutil_render_tag(
          'a',
          array(
            'href' => $uri->alter('l', $l - 1)->alter('r', $r - 1),
          ),
          "\xC2\xAB Previous Change");
      } else {
        $link_l = 'Original Change';
      }

      $link_r = null;
      if ($nav_r) {
        $link_r = phutil_render_tag(
          'a',
          array(
            'href' => $uri->alter('l', $l + 1)->alter('r', $r + 1),
          ),
          "Next Change \xC2\xBB");
      } else {
        $link_r = 'Most Recent Change';
      }

      $navigation_table =
        '<table class="phriction-history-nav-table">
          <tr>
            <td class="nav-prev">'.$link_l.'</td>
            <td class="nav-next">'.$link_r.'</td>
          </tr>
        </table>';
    }


    $output =
      '<div class="phriction-document-history-diff">'.
        $comparison_table->render().
        '<br />'.
        '<br />'.
        $navigation_table.
        '<table class="phriction-revert-table">'.
          '<tr><td>'.$revert_l.'</td><td>'.$revert_r.'</td>'.
        '</table>'.
        $output.
      '</div>';

    return $this->buildStandardPageResponse(
      array(
        $crumbs,
        $output,
      ),
      array(
        'title'     => 'Document History',
      ));
  }

  private function renderRevertButton(
    PhrictionContent $content,
    PhrictionContent $current) {

    $document_id = $content->getDocumentID();
    $version = $content->getVersion();

    if ($content->getChangeType() == PhrictionChangeType::CHANGE_DELETE) {
      // Don't show an edit/revert button for changes which deleted the content
      // since it's silly.
      return null;
    }

    if ($content->getID() == $current->getID()) {
      return phutil_render_tag(
        'a',
        array(
          'href'  => '/phriction/edit/'.$document_id.'/',
          'class' => 'button',
        ),
        'Edit Current Version');
    }


    return phutil_render_tag(
      'a',
      array(
        'href'  => '/phriction/edit/'.$document_id.'/?revert='.$version,
        'class' => 'button',
      ),
      'Revert to Version '.phutil_escape_html($version).'...');
  }

  private function renderComparisonTable(array $content) {

    $user = $this->getRequest()->getUser();

    $phids = mpull($content, 'getAuthorPHID');
    $handles = id(new PhabricatorObjectHandleData($phids))->loadHandles();

    $rows = array();
    foreach ($content as $c) {
      $rows[] = array(
        phabricator_date($c->getDateCreated(), $user),
        phabricator_time($c->getDateCreated(), $user),
        phutil_escape_html('Version '.$c->getVersion()),
        $handles[$c->getAuthorPHID()]->renderLink(),
        phutil_escape_html($c->getDescription()),
      );
    }


    $table = new AphrontTableView($rows);
    $table->setHeaders(
      array(
        'Date',
        'Time',
        'Version',
        'Author',
        'Description',
      ));
    $table->setColumnClasses(
      array(
        '',
        'right',
        'pri',
        '',
        'wide',
      ));

    return $table;
  }

}