<?php

final class PHUITimelineView extends AphrontView {

  private $events = array();
  private $id;
  private $shouldTerminate = false;
  private $shouldAddSpacers = true;
  private $pager;

  public function setID($id) {
    $this->id = $id;
    return $this;
  }

  public function setShouldTerminate($term) {
    $this->shouldTerminate = $term;
    return $this;
  }

  public function setShouldAddSpacers($bool) {
    $this->shouldAddSpacers = $bool;
    return $this;
  }

  public function setPager(AphrontCursorPagerView $pager) {
    $this->pager = $pager;
    return $this;
  }

  public function getPager() {
    return $this->pager;
  }

  public function addEvent(PHUITimelineEventView $event) {
    $this->events[] = $event;
    return $this;
  }

  public function render() {
    if ($this->getPager()) {
      if ($this->id === null) {
        $this->id = celerity_generate_unique_node_id();
      }
      Javelin::initBehavior(
        'phabricator-show-older-transactions',
        array(
          'timelineID' => $this->id,
        ));
    }
    $events = $this->buildEvents();

    return phutil_tag(
      'div',
      array(
        'class' => 'phui-timeline-view',
        'id' => $this->id,
      ),
      $events);
  }

  public function buildEvents() {
    require_celerity_resource('phui-timeline-view-css');

    $spacer = self::renderSpacer();

    $hide = array();
    $show = array();

    foreach ($this->events as $event) {
      if ($event->getHideByDefault()) {
        $hide[] = $event;
      } else {
        $show[] = $event;
      }
    }

    $events = array();
    if ($hide) {
      if ($this->getPager()) {

        $events[] = javelin_tag(
          'div',
          array(
            'sigil' => 'show-older-block',
            'class' => 'phui-timeline-older-transactions-are-hidden',
          ),
          array(
            pht('Older changes are hidden. '),
            ' ',
            javelin_tag(
              'a',
              array(
              'href' => (string) $this->getPager()->getNextPageURI(),
              'mustcapture' => true,
              'sigil' => 'show-older-link',
            ),
            pht('Show older changes.')),
          ));

      } else {

        $hidden = phutil_implode_html($spacer, $hide);
        $count = count($hide);

        $show_id = celerity_generate_unique_node_id();
        $hide_id = celerity_generate_unique_node_id();
        $link_id = celerity_generate_unique_node_id();

        Javelin::initBehavior(
          'phabricator-show-all-transactions',
          array(
            'anchors' => array_filter(mpull($hide, 'getAnchor')),
            'linkID' => $link_id,
            'hideID' => $hide_id,
            'showID' => $show_id,
          ));

        $events[] = phutil_tag(
          'div',
          array(
            'id' => $hide_id,
            'class' => 'phui-timeline-older-transactions-are-hidden',
          ),
          array(
            pht('%s older changes(s) are hidden.', new PhutilNumber($count)),
            ' ',
            javelin_tag(
              'a',
              array(
                'href' => '#',
                'mustcapture' => true,
                'id' => $link_id,
              ),
              pht('Show all changes.')),
          ));

        $events[] = phutil_tag(
          'div',
          array(
            'id' => $show_id,
            'style' => 'display: none',
          ),
          $hidden);
      }
    }

    if ($hide && $show) {
      $events[] = $spacer;
    }

    if ($show) {
      $events[] = phutil_implode_html($spacer, $show);
    }

    if ($events) {
      if ($this->shouldAddSpacers) {
        $events = array($spacer, $events, $spacer);
      }
    } else {
      $events = array($spacer);
    }

    if ($this->shouldTerminate) {
      $events[] = self::renderEnder(true);
    }

    return $events;
  }

  public static function renderSpacer() {
    return phutil_tag(
      'div',
      array(
        'class' => 'phui-timeline-event-view '.
                   'phui-timeline-spacer',
      ),
      '');
  }

  public static function renderEnder() {
    return phutil_tag(
      'div',
      array(
        'class' => 'phui-timeline-event-view '.
                   'the-worlds-end',
      ),
      '');
  }

}