<?php

/**
 * Alternative Calendar Widget
 * Differences to the default one:
 *  + CSS friendly output
 *  + Navigate trough months via Ajax
 *  + One-letter abbreviaton option
 *
 * @since 1.0
 *
 * @todo Add custom post type option
 */
 
 
unregister_widget('WP_Widget_Calendar'); 
register_widget('atom_widget_calendar'); 
 
class atom_widget_calendar extends WP_Widget{

  function atom_widget_calendar(){
    $widget_ops = array('classname' => 'calendar', 'description' => _a("A calendar of your site's posts"));
    $this->WP_Widget('atom-calendar', _a("Calendar"), $widget_ops);

    atom_add('ajax_requests', array(&$this, 'ajax'));

    // include in jQuery(document).ready()
    atom_add('jquery_init', array(&$this, 'js'));
  }

  function js(){
    // we need to process all instances because this function gets to run only once
    $widget_settings = atom_get_options($this->option_name);

    foreach((array)$widget_settings as $instance => $options):

      // identify instance
      $id = "{$this->id_base}-{$instance}";
      $block_id = "instance-{$id}";

      if (isset($options['ajax']) && $options['ajax'] && is_active_widget(false, $id, $this->id_base)): ?>

      $("#<?php echo $block_id; ?>").delegate("a.control", "click", function(){
        var reqdate = $(this).attr('rel').split(/-/g);
        $.ajax({
          type: "GET",
          url: "<?php echo home_url('/'); //echo atom_get_current_page_url(); ?>",
          context: this,
          data: { id: "<?php echo $block_id; ?>",
                  initial: <?php echo intval($options['initial']); ?>,
                  reqmonth: reqdate[0],
                  reqyear: reqdate[1],
                  _ajax_nonce: "<?php atom_nonce('get_calendar'); ?>",
                  atom: "get_calendar" },
          dataType: 'json',
          beforeSend: function() { $(this).addClass("loading"); },
          complete: function() { $(this).removeClass("loading"); },
          success: function(response){
            if(response.output != '') $("#<?php echo $block_id; ?> .calendar-block").html(response.output);
          }
        });
        return false;

      });

      <?php endif;
    endforeach;
  }

  function ajax(){
    if(atom_ajax_request('get_calendar')):
      atom_ajax_header('get_calendar', 'application/json');
      $output = $this->get_calendar((bool)$_GET['initial'], intval($_GET['reqmonth']), intval($_GET['reqyear']));
      echo json_encode(array('output' => $output));
      exit();
    endif;
  }

  /* same as the wp function, with small changes */
  function get_calendar($initial = true, $req_m = NULL, $req_y = NULL) {
    global $wpdb, $m, $monthnum, $year, $wp_locale, $posts;

    $post_type = 'post'; // @todo: custom post types -- need get_day_link()

    // ajax?
    if($req_m) $monthnum = $req_m;
    if($req_y) $year = $req_y;

    $cache = array();
    $key = md5($m.$monthnum.$year);
    if ($cache = wp_cache_get('atom_get_calendar', 'calendar'))
      if (is_array($cache) && isset($cache[$key]))
        return apply_filters('atom_get_calendar', $cache[$key]);

    if (!is_array($cache)) $cache = array();

    // Quick check. If we have no posts at all, abort!
    if (!$posts):
      $gotsome = $wpdb->get_var("SELECT 1 as test FROM {$wpdb->posts} WHERE post_type = '{$post_type}' AND post_status = 'publish' LIMIT 1");
      if (!$gotsome):
        $cache[ $key ] = '';
        wp_cache_set('atom_get_calendar', $cache, 'calendar');
        return;
      endif;
    endif;

    if (isset($_GET['w'])) $w = ''.intval($_GET['w']);

    // week_begins = 0 stands for Sunday
    $week_begins = intval(atom_get_options('start_of_week'));

    // Let's figure out when we are
    if (!empty($monthnum) && !empty($year)){
      $thismonth = ''.zeroise(intval($monthnum), 2);
      $thisyear = ''.intval($year);
    } elseif (!empty($w)) {
      // We need to get the month from MySQL
      $thisyear = ''.intval(substr($m, 0, 4));
      $d = (($w - 1) * 7) + 6; //it seems MySQL's weeks disagree with PHP's
      $thismonth = $wpdb->get_var("SELECT DATE_FORMAT((DATE_ADD('${thisyear}0101', INTERVAL {$d} DAY)), '%m')");
    } elseif (!empty($m)){
      $thisyear = ''.intval(substr($m, 0, 4));
      if (strlen($m) < 6) $thismonth = '01'; else $thismonth = ''.zeroise(intval(substr($m, 4, 2)), 2);
    } else {
      $thisyear = gmdate('Y', current_time('timestamp'));
      $thismonth = gmdate('m', current_time('timestamp'));
    }

    $unixmonth = mktime(0, 0 , 0, $thismonth, 1, $thisyear);

    // Get the next and previous month and year with at least one post
    $previous = $wpdb->get_row("SELECT DISTINCT MONTH(post_date) AS month, YEAR(post_date) AS year
                                FROM {$wpdb->posts}
                                WHERE post_date < '{$thisyear}-{$thismonth}-01'
                                AND post_type = '{$post_type}' AND post_status = 'publish'
                                ORDER BY post_date DESC
                                LIMIT 1");
    $next = $wpdb->get_row("SELECT	DISTINCT MONTH(post_date) AS month, YEAR(post_date) AS year
                            FROM {$wpdb->posts}
                            WHERE post_date > '{$thisyear}-{$thismonth}-01'
                            AND MONTH(post_date) != MONTH('{$thisyear}-{$thismonth}-01')
                            AND post_type = '{$post_type}' AND post_status = 'publish'
                            ORDER BY post_date ASC
                            LIMIT 1");

    /* translators: Calendar caption: 1: month name, 2: 4-digit year */
    $calendar_caption = _x('%1$s %2$s', 'calendar caption');

    $calendar_output = '<div class="top">';
    $calendar_output .= '<h4>'.sprintf($calendar_caption, $wp_locale->get_month($thismonth), date('Y', $unixmonth)).'</h4>';

    if ($previous):
      $calendar_output .= "\n\t\t<a class=\"prev control\" rel=\"{$previous->month}-{$previous->year}\" href=\"".get_month_link($previous->year, $previous->month)."\" title=\"".sprintf(_a('View posts for %1$s %2$s'), $wp_locale->get_month($previous->month), date('Y', mktime(0, 0 , 0, $previous->month, 1, $previous->year)))."\">&laquo; ".$wp_locale->get_month_abbrev($wp_locale->get_month($previous->month))."</a>";
    endif;

    if ($next):
      $calendar_output .= "\n\t\t<a class=\"next control\" rel=\"{$next->month}-{$next->year}\" href=\"".get_month_link($next->year, $next->month)."\" title=\"".esc_attr(sprintf(_a('View posts for %1$s %2$s'), $wp_locale->get_month($next->month), date('Y', mktime(0, 0 , 0, $next->month, 1, $next->year))))."\">".$wp_locale->get_month_abbrev($wp_locale->get_month($next->month))." &raquo;</a>";
    endif;

    $calendar_output .= '</div>';

    $calendar_output .= '<table class="calendar" summary="'._a('Calendar').'"><thead><tr>';

    $myweek = array();
    for ($wdcount=0; $wdcount<=6; $wdcount++)
      $myweek[] = $wp_locale->get_weekday(($wdcount+$week_begins)%7);

    foreach ($myweek as $wd):
      $day_name = (true == $initial) ? $wp_locale->get_weekday_initial($wd) : $wp_locale->get_weekday_abbrev($wd);
      $wd = esc_attr($wd);
      $calendar_output .= "\n\t\t<th scope=\"col\" title=\"{$wd}\">{$day_name}</th>";
    endforeach;

    $calendar_output .= '</tr></thead> <tbody><tr>';

    // Get days with posts
    $dayswithposts = $wpdb->get_results("SELECT DISTINCT DAYOFMONTH(post_date)
                                         FROM {$wpdb->posts} WHERE MONTH(post_date) = '{$thismonth}'
                                         AND YEAR(post_date) = '$thisyear'
                                         AND post_type = '{$post_type}' AND post_status = 'publish'
                                         AND post_date < '".current_time('mysql').'\'', ARRAY_N);
    if ($dayswithposts)
      foreach ((array) $dayswithposts as $daywith) $daywithpost[] = $daywith[0];
    else $daywithpost = array();

    if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== false || stripos($_SERVER['HTTP_USER_AGENT'], 'camino') !== false || stripos($_SERVER['HTTP_USER_AGENT'], 'safari') !== false)
      $ak_title_separator = "\n";
    else
      $ak_title_separator = ', ';

    $ak_titles_for_day = array();
    $ak_post_titles = $wpdb->get_results("SELECT ID, post_title, DAYOFMONTH(post_date) as dom
                                          FROM {$wpdb->posts}
                                          WHERE YEAR(post_date) = '{$thisyear}'
                                          AND MONTH(post_date) = '{$thismonth}'
                                          AND post_date < '".current_time('mysql')."'
                                          AND post_type = '{$post_type}' AND post_status = 'publish'");
    if ($ak_post_titles)
      foreach ((array)$ak_post_titles as $ak_post_title):
        $post_title = esc_attr(apply_filters('the_title', $ak_post_title->post_title, $ak_post_title->ID));
        if (empty($ak_titles_for_day["day_{$ak_post_title->dom}"])) $ak_titles_for_day["day_{$ak_post_title->dom}"] = '';
        if (empty($ak_titles_for_day[$ak_post_title->dom])) // first one
          $ak_titles_for_day[$ak_post_title->dom] = $post_title;
        else
          $ak_titles_for_day[$ak_post_title->dom] .= $ak_title_separator.$post_title;
      endforeach;

    // See how much we should pad in the beginning
    $pad = calendar_week_mod(date('w', $unixmonth)-$week_begins);
    if (0 != $pad) $calendar_output .= '<td colspan="'.esc_attr($pad).'" class="pad">&nbsp;</td>';

    $daysinmonth = intval(date('t', $unixmonth));
    for ($day = 1; $day <= $daysinmonth; ++$day):
      if (isset($newrow) && $newrow) $calendar_output .= "\n\t</tr>\n\t<tr>\n\t\t";
      $newrow = false;

      if ($day == gmdate('j', current_time('timestamp')) && $thismonth == gmdate('m', current_time('timestamp')) && $thisyear == gmdate('Y', current_time('timestamp')))
        $calendar_output .= '<td class="today">';
      else
        $calendar_output .= '<td>';

      if (in_array($day, $daywithpost)) // any posts today?
        $calendar_output .= '<a href="'.get_day_link($thisyear, $thismonth, $day)."\" title=\"".esc_attr($ak_titles_for_day[$day])."\">$day</a>";
      else
        $calendar_output .= "<span>{$day}</span>";
      $calendar_output .= '</td>';
      if (6 == calendar_week_mod(date('w', mktime(0, 0 , 0, $thismonth, $day, $thisyear))-$week_begins)) $newrow = true;
    endfor;

    $pad = 7 - calendar_week_mod(date('w', mktime(0, 0 , 0, $thismonth, $day, $thisyear))-$week_begins);
    if ($pad != 0 && $pad != 7)
      $calendar_output .= "\n\t\t".'<td class="pad" colspan="'.esc_attr($pad).'">&nbsp;</td>';

    $calendar_output .= "\n\t</tr>\n\t</tbody>\n\t</table>";

    $cache[$key] = $calendar_output;
    wp_cache_set('atom_get_calendar', $cache, 'calendar');

    return apply_filters('atom_get_calendar', $calendar_output); // no point using get_calendar(), output is different...
  }

  function widget($args, $instance){
    extract($args);
    $instance = wp_parse_args($instance, $this->defaults());

    $initial = isset($instance['initial']) ? $instance['initial'] : false;
    $ajax = isset($instance['ajax']) ? $instance['ajax'] : false;

    echo $before_widget;
    echo '<div class="calendar-block">'.$this->get_calendar($initial).'</div>';
    echo $after_widget;
  }

  function update($new_instance, $old_instance){
    $instance = $old_instance;
    $instance['initial'] = (bool)$new_instance['initial'];
    $instance['ajax'] = (bool)$new_instance['ajax'];
    return wp_parse_args($instance, $this->defaults());
  }

  function defaults(){
    // default settings
    return apply_filters('atom_widget_calendar_defaults', array(
      'title' => _a('Calendar'),
      'initial' => false,
      'ajax' => true,
    ), $this);
  }

  function form($instance){
    $instance = wp_parse_args($instance, $this->defaults());
    ?>
    <div <?php atom_widget_form_class($this); ?>>
    <p>
     <label for="<?php echo $this->get_field_id('ajax'); ?>" <?php if(!atom_get_options('jquery')) echo "class=\"disabled\""; ?>>
     <input <?php if(!atom_get_options('jquery')) echo "disabled=\"disabled\""; ?> type="checkbox" <?php checked($instance['ajax'], true); ?> id="<?php echo $this->get_field_id('ajax'); ?>" name="<?php echo $this->get_field_name('ajax'); ?>" /> <?php _ae('Use AJAX?'); ?></label>

     <br />
     <label for="<?php echo $this->get_field_id('initial'); ?>">
     <input type="checkbox" <?php checked($instance['initial'], true); ?> id="<?php echo $this->get_field_id('initial'); ?>" name="<?php echo $this->get_field_name('initial'); ?>" /> <?php _ae('One-letter day abbreviation?'); ?></label>
    </p>
    </div>
    <?php
  }
}