--- lineage.module	2008-09-05 02:15:48.000000000 -0500
+++ lineage-new.module	2009-10-25 08:13:20.000000000 -0500
@@ -14,23 +14,149 @@ function lineage_taxonomy($op, $type, $a
       break;
     case 'insert':
     case 'update':
-      lineage_update_term($array);
+      // Skip if we are on the admin reordering pages; 
+      // it will happen be triggered by our submit handler after processing.
+      $arg = arg();
+      if (arg() != array('admin','content','taxonomy',$array['vid'])) {
+        lineage_update_term($array);
+      }
       break;
   }
 }
 
+/** 
+ * Implements hook_form_taxonomy_overview_terms_alter().
+ */
+function lineage_form_taxonomy_overview_terms_alter(&$form,&$form_state) {
+  // Override submit handler.
+  $form['#submit'] = array('lineage_taxonomy_overview_terms_submit');
+}
+
+/**
+ * Submit handler for taxonomy_overview_terms (the admin term reordering form).
+ * Overrides handling so that we can update lineages after the new term 
+ * weights are processed.
+ * This function is mostly a clone of taxonomy_overview_terms_submit, with
+ * the addition of lineage_update_all calls in the appropriate places.
+ */
+function lineage_taxonomy_overview_terms_submit(&$form,&$form_state) {
+  if ($form_state['clicked_button']['#value'] == t('Reset to alphabetical')) {
+    // Execute the reset action.
+    if ($form_state['values']['reset_alphabetical'] === TRUE) {
+      taxonomy_vocabulary_confirm_reset_alphabetical_submit($form, $form_state);
+      lineage_update_all($form_state['values']['vid']);
+      return;
+    }
+    // Rebuild the form to confirm the reset action.
+    $form_state['rebuild'] = TRUE;
+    $form_state['confirm_reset_alphabetical'] = TRUE;
+    return;
+  }
+
+  $order = array_flip(array_keys($form['#post'])); // Get the $_POST order.
+  $form_state['values'] = array_merge($order, $form_state['values']); // Update our original form with the new order.
+
+  $vocabulary = $form['#vocabulary'];
+  $hierarchy = 0; // Update the current hierarchy type as we go.
+
+  $changed_terms = array();
+  $tree = taxonomy_get_tree($vocabulary['vid']);
+
+  if (empty($tree)) {
+    return;
+  }
+
+  // Build a list of all terms that need to be updated on previous pages.
+  $weight = 0;
+  $term = (array)$tree[0];
+  while ($term['tid'] != $form['#first_tid']) {
+    if ($term['parents'][0] == 0 && $term['weight'] != $weight) {
+      $term['parent'] = $term['parents'][0];
+      $term['weight'] = $weight;
+      $changed_terms[$term['tid']] = $term;
+    }
+    $weight++;
+    $hierarchy = $term['parents'][0] != 0 ? 1 : $hierarchy;
+    $term = (array)$tree[$weight];
+  }
+
+  // Renumber the current page weights and assign any new parents.
+  $level_weights = array();
+  foreach ($form_state['values'] as $tid => $values) {
+    if (isset($form[$tid]['#term'])) {
+      $term = $form[$tid]['#term'];
+      // Give terms at the root level a weight in sequence with terms on previous pages.
+      if ($values['parent'] == 0 && $term['weight'] != $weight) {
+        $term['weight'] = $weight;
+        $changed_terms[$term['tid']] = $term;
+      }
+      // Terms not at the root level can safely start from 0 because they're all on this page.
+      elseif ($values['parent'] > 0) {
+        $level_weights[$values['parent']] = isset($level_weights[$values['parent']]) ? $level_weights[$values['parent']] + 1 : 0;
+        if ($level_weights[$values['parent']] != $term['weight']) {
+          $term['weight'] = $level_weights[$values['parent']];
+          $changed_terms[$term['tid']] = $term;
+        }
+      }
+      // Update any changed parents.
+      if ($values['parent'] != $term['parent']) {
+        $term['parent'] = $values['parent'];
+        $changed_terms[$term['tid']] = $term;
+      }
+      $hierarchy = $term['parent'] != 0 ? 1 : $hierarchy;
+      $weight++;
+    }
+  }
+
+  // Build a list of all terms that need to be updated on following pages.
+  for ($weight; $weight < count($tree); $weight++) {
+    $term = (array)$tree[$weight];
+    if ($term['parents'][0] == 0 && $term['weight'] != $weight) {
+      $term['parent'] = $term['parents'][0];
+      $term['weight'] = $weight;
+      $changed_terms[$term['tid']] = $term;
+    }
+    $hierarchy = $term['parents'][0] != 0 ? 1 : $hierarchy;
+  }
+
+  // Save all updated terms.
+  foreach ($changed_terms as $term) {
+    taxonomy_save_term($term);
+  }
+
+  // Update the vocabulary hierarchy to flat or single hierarchy.
+  if ($vocabulary['hierarchy'] != $hierarchy) {
+    $vocabulary['hierarchy'] = $hierarchy;
+    taxonomy_save_vocabulary($vocabulary);
+  }
+
+  lineage_update_all($vocabulary['vid']);
+}
+
 function lineage_enable() {
   drupal_set_message(t("Updated @number taxonomy records.", array('@number' => lineage_update_all())));
 }
 
-function lineage_update_all() {
-  $count = 0;
+/**
+ * Updates all lineage records.
+ * @param $vid=false If passed, limit to records for only one vocabulary.
+ * @return $count The number of records updated.
+ */
+function lineage_update_all($vid=false) {
+  // If we are only updating one vocabulary, select only those terms.
+  $base_q = "SELECT td.tid, td.name, td.weight, td.vid FROM {term_data} td LEFT JOIN {term_hierarchy} th ON th.tid = td.tid WHERE th.parent = 0";
 
-  $result = db_query("SELECT td.tid, td.name, td.weight FROM {term_data} td LEFT JOIN {term_hierarchy} th ON th.tid = td.tid WHERE th.parent = 0");
-  while ($term = db_fetch_object($result)) {
-    $count += lineage_update_term($term);
+  if ($vid) {
+    $result = db_query($base_q." AND td.vid = '%d'",$vid);
+  }
+  else {
+    $result = db_query($base_q);
   }
 
+  $count = 0;
+  while ($term = db_fetch_object($result)) {
+    $count += lineage_update_term($term,true);
+  }
   return $count;
 }