/**

 * \brief

 *   Crawl CCBCMD's registration stuffage.

 *

 * \param $semesters

 *   The array of Semester objects which I should populate.

 * \param $school_crawl_log

 *   The school_crawl_log handle.

 * \return

 *   1 on failure, 0 on success.

 */

function ccbcmd_crawl(array &$semesters, &$school_crawl_log)

{

  $cookies = array();

  /*

   * It seems that http://ccbcmd.edu/schedule/sched.html is what we're

   * meant to start from. That's just a redirect to some other page

   * from which we get a listing of available semesters and choose

   * one.

   */

  $uri = 'http://ccbcmd.edu/schedule/sched.html';

  $semesters_dom = new DOMDocument();

  $semesters_dom->loadHTML(school_crawl_geturi($uri, $cookies, $school_crawl_log, NULL, TRUE, 'ccbcmd_crawl_curlhook'));

  $semesters_select_node = $semesters_dom->getElementById('term_input_id');

  if ($semesters_select_node === NULL)

    {

      school_crawl_logf($school_crawl_log, 0, "Could not get list of available semesters to choose from.");

      return 1;

    }

  $semester_stage_uri = $uri;

  $semesters_form = school_crawl_element_ancestor($semesters_select_node, 'form');

  if ($semesters_form === NULL)

    {

      school_crawl_logf($school_crawl_log, 0, "Unable to find <form /> associated with semester.");

      return 1;

    }

  $semesters_post_save = school_crawl_form($semesters_form);

  foreach ($semesters_select_node->childNodes as $semesters_option_node)

    {

      $semester_text = $semesters_option_node->textContent;

      $semester_value = $semesters_option_node->getAttribute('value');

      if (empty($semester_value))

	/* skip the empty ``None'' semester */

	continue;

      if (stripos($semester_text, 'continuing') !== FALSE)

	/* skip the year-long semesters dedicated to continuing education */

	continue;

      $semester_text_parts = explode(' ', $semester_text);

      $semester_season = $semester_text_parts[0];

      $semester_year = $semester_text_parts[1];

      /* the college has two separate summer sessions, so distinguish between them */

      if (preg_match(';session ([0-9]+);i', $semester_text, $matches))

	$semester_season .= '_' . $matches[1];

      school_crawl_logf($school_crawl_log, 6, "Crawling semester %s:%s -> %s.", $semester_year, $semester_season, trim($semester_text));

      $semester = new Semester($semester_year, strtolower($semester_season));

      school_crawl_logf($school_crawl_log, 8, "Found semester: %s=``%s''=``%s''.",

			$semester_value, $semester->id(), trim($semesters_option_node->textContent));

  /* load stored semester-page URI / form data */

  $semesters_post = $semesters_post_save;

  $uri = $semester_stage_uri;

  $semesters_post[$semesters_select_node->getAttribute('name')] = $semester_value;

  $subjects_dom = new DOMDocument();

  $uri = school_crawl_url($uri, $semesters_form->getAttribute('action'));

  $subjects_dom->loadHTML(school_crawl_geturi($uri, $cookies, $school_crawl_log, $semesters_post, TRUE, 'ccbcmd_crawl_curlhook'));

  $subjects_form_nodelist = $subjects_dom->getElementsByTagName('form');

  if (!$subjects_form_nodelist->length)

    {

      school_crawl_logf($school_crawl_log, 0, "Unable to find <form /> to submit for the subjects-choosing page.");

      return 1;

    }

  $subjects_form_node = $subjects_form_nodelist->item(0);

  $subjects_post = school_crawl_form($subjects_form_node);

  $subjects_select_node = $subjects_dom->getElementById('subj_id');

  foreach ($subjects_select_node->childNodes as $subjects_option_node)

    if (!strcasecmp('all', trim($subjects_option_node->textContent)))

      $subjects_post[$subjects_select_node->getAttribute('name')][] = $subjects_option_node->getAttribute('value');

  $courses_dom = new DOMDocument();

  $uri = school_crawl_url($uri, $subjects_form_node->getAttribute('action'));

  $courses_dom->loadHTML(school_crawl_geturi($uri, $cookies, $school_crawl_log, $subjects_post, TRUE, 'ccbcmd_crawl_curlhook'));

  $courses_xpath = new DOMXPath($courses_dom);

  /* The second row of the table has all of the headers in it */

  $tr_header_nodelist = $courses_xpath->query('//table[@class="datadisplaytable" and position()=1]//tr[position()=2]');

  if (!$tr_header_nodelist->length)

    {

      school_crawl_logf($school_crawl_log, 0, "Unable to find the row of the course/section data table which gives us the mappings of column names onto columns.");

      return 1;

    }

  $tr_header_node = $tr_header_nodelist->item(0);

  $section_offsets = array(

			   'registration_number' => school_crawl_table_resolve_column($tr_header_node, 'CRN'),

			   'section_id' => school_crawl_table_resolve_column($tr_header_node, 'subj/crse/sec'),

			   /* there's a boolean column which says whether or not the course has any prerequisites/corequisites.... */

			   'credits' => school_crawl_table_resolve_column($tr_header_node, 'credhrs'),

			   /* there's a column for the number of contact hours, vs. credit hours */

			   'dates' => school_crawl_table_resolve_column($tr_header_node, 'sessiondates'),

			   );

  foreach (array('title', 'days', 'times', 'instructor', 'location') as $column_key)

    $section_offsets[$column_key] = school_crawl_table_resolve_column($tr_header_node, $column_key);

  /* there's also a column for ``session dates'' */

  /* error check and calculate the number of children that a node must have to be  */

  $max_offset = 0;

  foreach ($section_offsets as $name => $value)

    {

      if ($value === FALSE)

	{

	  school_crawl_logf($school_crawl_log, 0, "Unable to find column offset for `%s'.",

		  $name);

	  return 1;

	}

      else

	school_crawl_logf($school_crawl_log, 9, "%s -> %s", $name, $value);

      $max_offset = max($max_offset, $value);

    }

  foreach ($courses_xpath->query('//table[@class="datadisplaytable" and position()=1]//tr') as $tr_node)

    {

      $children = school_crawl_table_rownodes($tr_node);

      if ($children->length < $max_offset)

	/*

	 * Skip this row because it doesn't have all of the columns we

	 * want and thus it can't be a row containing information

	 * about a section.

	 */

	continue;

      if (!strcmp($children->item($section_offsets['section_id'])->tagName, 'th'))

	/*

	 * We've hit one of the <tr/>s filled with <th/>s. Skip this one.

	 */

	continue;

      /*

       * There are some rows with the time set to TBA and with empty

       * section_id columns. Respond to this by skipping empty

       * section_id columns since there's no useful data in these

       * rows. We use strlen() < 3 because trim() doesn't take care of

       *   :-/

       */

      $section_id = trim($children->item($section_offsets['section_id'])->textContent);

      if (strlen($section_id) < 3)

	continue;

      $section_id_parts = Section::parse($section_id);

      $registration_number = $children->item($section_offsets['registration_number'])->textContent;

      $instructor = $children->item($section_offsets['instructor'])->textContent;

      $section_meetings = array();

      {

	$time_range_text = $children->item($section_offsets['times'])->textContent;

	if (strpos($time_range_text, 'TBA') !== FALSE)

	  {

	    /*

	     * Add the section to the autocomplete list, just without

	     * any meeting info (i.e., $section_meetings is still

	     * empty now).

	     */

	    $semester->section_add($section_id_parts['department'], $section_id_parts['course'],

				   new Section($section_id_parts['section'], $section_meetings, $registration_number));

	    continue;

	  }

	if (($dash_pos = strpos($time_range_text, '-')) === FALSE)

	  {

	    school_crawl_logf($school_crawl_log, 0, "Unable to understand course's time range format, cannot find dash: ``%s''.",

		    $time_range_text);

	    return 1;

	  }

	$time_start_text = substr($time_range_text, 0, $dash_pos);

	$time_start = strptime($time_start_text, '%I:%M %p');

	$time_end_text = substr($time_range_text, $dash_pos + 1);

	/*

	 * Make sure that _only_ one date range is specified to ensure

	 * data integrity. I.e., make sure that the college doesn't

	 * suddenly support multiple meeting times without our

	 * anticipating that and then cause us to have invalid

	 * data. ;-). --binki

	 */

	if (strpos($time_end_text, '-') !== FALSE)

	  {

	    school_crawl_logf($school_crawl_log, 0, "College seems to support multiple meeting times per semester which we don't know how to parse (even though slate_permutate itself can handle this situation): ``%s'' time_end_text: ``%s''.",

		    $time_range_text, $time_end_text);

	    return 1;

	  }

	$time_end = strptime($time_end_text, '%I:%M %p');

	if ($time_end === FALSE || $time_start === FALSE)

	  {

	    school_crawl_logf($school_crawl_log, 0, "Error parsing start or end time: start: ``%s'' end: ``%s''.",

		    $time_start_text, $time_end_text);

	    return 1;

	  }

	$days = school_crawl_days_str_format($school_crawl_log, $children->item($section_offsets['days'])->textContent);

	$section_meetings[] = new SectionMeeting($days, school_crawl_time_format($time_start), school_crawl_time_format($time_end),

						 $children->item($section_offsets['location'])->textContent,

						 $instructor);

	/* check if a semester's date range should be increased */

	$section_dates = $children->item($section_offsets['dates'])->textContent;

	if (preg_match(';^([0-9]+)/([0-9]+)-([0-9]+)/([0-9]+)$;', $section_dates, $section_dates_matches))

	  {

	    $semester->time_start_set_test(mktime(0, 0, 0, $section_dates_matches[1], $section_dates_matches[2], $semester->year_get()));

	    $semester->time_end_set_test(  mktime(0, 0, 0, $section_dates_matches[3], $section_dates_matches[4], $semester->year_get()));

	  }

      }

      $semester->section_add($section_id_parts['department'], $section_id_parts['course'],

			     new Section($section_id_parts['section'], $section_meetings, $registration_number));

    }

  $semesters[] = $semester;

    }

  return 0;

}