<?php
// $Id: smartqueue.module,v 1.1.2.4 2007-08-16 00:06:04 merlinofchaos Exp $

/**
 * Implementation of hook_nodequeue_info()
 */
function smartqueue_nodequeue_info() {
  return array('smartqueue_taxonomy' => array(
    'title' => t('Taxonomy queue'),
    'description' => t('Each particular grouping of taxonomy terms from the selected vocabularlies have their own unique subqueue. You can place nodes into any of these subqueues based on which terms that node has been tagged with. Using this with large or too many taxonomies may degrade performance.'),
    ));
}

/**
 * Implementation of hook_nodequeue()
 */
function smartqueue_taxonomy_nodequeue_form($queue, &$form) {
  foreach (taxonomy_get_vocabularies() as $vid => $vocabulary) {
    $options[$vid] = $vocabulary->name;
  }
  $form['placeholder']['vocabularies'] = array(
    '#type' => 'checkboxes',
    '#title' => t('Vocabularies'),
    '#description' => t('Select which vocabularies to use; each unique combination of terms from all of these vocabularies will have a subqueue.'),
    '#options' => $options,
  );

  $form['subqueue_title'] = array(
    '#type' => 'textfield',
    '#title' => t('Subqueue title'),
    '#default_value' => $queue->subqueue_title,
    '#size' => 50,
    '#maxlength' => 64,
    '#description' => t('What to display for the subqueue title; use %subqueue to embed the actual subqueue title. This is used to distinguish multiple nodequeues with subqueues from each other, as internal subqueue title is filled automatically.'),
  );
  

  if ($queue->qid) {
    $form['placeholder']['vocabularies']['#disabled'] = TRUE;
    $form['placeholder']['vocabularies']['#default_value'] = explode('-', $queue->reference);
  }
}

/**
 * Implementation of hook_nodequeue()
 */
function smartqueue_taxonomy_nodequeue_form_validate($queue, $form_values, &$form) {
  if (!isset($queue->qid)) {
    $vids = array_keys(array_filter($form_values['vocabularies']));
    if (empty($vids)) {
      form_error($form['placeholder']['vocabularies'], t('You must select at least one vocabulary.'));
    }

    // Convert this to our reference.
    form_set_value($form['reference'], implode('-', $vids));
  }
}


/**
 * Implementation of hook_nodequeue_subqueues()
 */
function smartqueue_taxonomy_nodequeue_subqueues(&$queue, $node) {
  foreach (explode('-', $queue->reference) as $vid) {
    $vids[$vid] = array();
  }

  foreach ($node->taxonomy as $tid => $term) {
    if (isset($vids[$term->vid])) {
      $vids[$term->vid][] = $tid;
    }
  }

  // Forbid NO terms being set, but allow
  // various non-terms to be set.

  $empty = TRUE;
  foreach ($vids as $vid => $tids) {
    if (!empty($tids)) {
      $empty = FALSE;
    }
    $vids[$vid][] = 0;
  }

  if ($empty) {
    return;
  }

  $references = smartqueue_build_string(array_filter($vids));
  // Because of how we built this, the last one will always be all zeros. Lose it.
  array_pop($references);

  // We're returning an array of references for efficiency, but we also have
  // to check to see if the references we've generated exist. If they don't,
  // we have to create them.
  $exists = array();
  $subqueues = nodequeue_load_subqueues_by_reference(array($queue->qid => $references));
  foreach ($subqueues as $subqueue) {
    $exists[$subqueue->reference] = TRUE;
  }

  foreach ($references as $reference) {
    if (empty($exists[$reference])) {
      nodequeue_add_subqueue($queue, smartqueue_taxonomy_nodequeue_subqueue_title($queue, $reference), $reference);
    }
  }
  return $references;
}

/**
 * Build an array of strings that represents all of the possible term
 * combinations
 */
function smartqueue_build_string($arrays) {
  $array = array_shift($arrays);
  $term = '';
  if (empty($arrays))  {
    return $array;
  }

  $substrings = smartqueue_build_string($arrays);
  $strings = array();

  foreach ($array as $term) {
    foreach ($substrings as $string) {
      $strings[] = "$term-$string";
    }
  }

  return $strings;
}

function smartqueue_taxonomy_nodequeue_subqueue_title($queue, $reference) {
  $vids = explode('-', $queue->reference);
  $tids = explode('-', $reference);
  foreach ($vids as $vid) {
    $tid = array_shift($tids);
    // $tid can be 0, specifically meaning this term is unset.
    if ($tid) {
      $terms = smartqueue_taxonomy_get_terms($vid);
      $titles[$tid] = check_plain($terms[$tid]);
    }
  }
  return implode('-', $titles);
}

/**
 * Get a list of terms
 */
function smartqueue_taxonomy_get_terms($vid) {
  static $cache = array();
  if (!isset($cache[$vid])) {
    $cache[$vid] = array();
    $result = db_query("SELECT tid, name FROM {term_data} WHERE vid = %d", $vid);
    while ($term = db_fetch_object($result)) {
      $cache[$vid][$term->tid] = $term->name;
    }
  }
  return $cache[$vid];
}


// TODO:
// Implement hook_taxonomy to delete subqueues when terms are deleted.
// And to update titles when taxonomy terms are changed.
function smartqueue_taxonomy_taxonomy($op, $type, $array = NULL) {
  // Since this is a relatively rare operation, and I'm out of time for this
  // project, I'm leaving this for some enterprising developer who needs this.
}