Patch for tickets #1428 and #1760

Create the concept of a Photo_Display_Context.  If the user is browsing a dynamic album (i.e. tags) and chooses to
look at an image in that album.  The display of the image happens correctly, but the 'next' and 'previous' buttons
are no longer consistent.  When one of these is clicked, Gallery  will open the adjacent image in the actuall album,
not the dynamic album.

4 files changed, 110 insertions, 18 deletions

diff --git a/modules/tag/controllers/tag.php b/modules/tag/controllers/tag.php
index 7786daa1..06e2b5ed 100644
--- a/modules/tag/controllers/tag.php
+++ b/modules/tag/controllers/tag.php
@@ -22,7 +22,22 @@ class Tag_Controller extends Controller {
     $tag_id = $function;
     $tag = ORM::factory("tag")->where("id", "=", $tag_id)->find();
     $page_size = module::get_var("gallery", "page_size", 9);
-    $page = (int) Input::instance()->get("page", "1");
+
+    $input = Input::instance();
+    $show = $input->get("show");
+
+    if ($show) {
+      $child = ORM::factory("item", $show);
+      $index = tag::get_position($tag, $child);
+      if ($index) {
+        $page = ceil($index / $page_size);
+        $uri = "tag/$tag_id/" . urlencode($tag->name);
+        url::redirect($uri . ($page == 1 ? "" : "?page=$page"));
+      }
+    } else {
+      $page = (int) $input->get("page", "1");
+    }
+
     $children_count = $tag->items_count();
     $offset = ($page-1) * $page_size;
     $max_pages = max(ceil($children_count / $page_size), 1);
@@ -35,6 +50,11 @@ class Tag_Controller extends Controller {
     }
 
     $root = item::root();
+    $title = t("Tag: %tag_name", array("tag_name" => $tag->name));
+    Display_Context::factory("tag")
+      ->set(array("tag" => $tag))
+      ->save();
+
     $template = new Theme_View("page.html", "collection", "tag");
     $template->set_global(
       array("page" => $page,
diff --git a/modules/tag/helpers/tag.php b/modules/tag/helpers/tag.php
index c21104ee..83a00080 100644
--- a/modules/tag/helpers/tag.php
+++ b/modules/tag/helpers/tag.php
@@ -136,4 +136,23 @@ class tag_Core {
     // extremely rare case.
     db::build()->delete("tags")->where("count", "=", 0)->execute();
   }
+
+  /**
+   * Find the position of the given item in the tag collection.  The resulting
+   * value is 1-indexed, so the first child in the album is at position 1.
+   *
+   * @param Tag_Model  $tag
+   * @param Item_Model $item
+   * @param array      $where an array of arrays, each compatible with ORM::where()
+   */
+  static function get_position($tag, $item, $where=array()) {
+    return ORM::factory("item")
+      ->viewable()
+      ->join("items_tags", "items.id", "items_tags.item_id")
+      ->where("items_tags.tag_id", "=", $tag->id)
+      ->where("items.id", "<=", $item->id)
+      ->merge_where($where)
+      ->order_by("items.id")
+      ->count_all();
+  }
 }
\ No newline at end of file
diff --git a/modules/tag/libraries/Tag_Display_Context.php b/modules/tag/libraries/Tag_Display_Context.php
new file mode 100644
index 00000000..47c79088
--- /dev/null
+++ b/modules/tag/libraries/Tag_Display_Context.php
@@ -0,0 +1,49 @@
+<?php defined("SYSPATH") or die("No direct script access.");
+/**
+ * Gallery - a web based photo album viewer and editor
+ * Copyright (C) 2000-2011 Bharat Mediratta
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+class Tag_Display_Context_Core extends Display_Context {
+  protected function __construct() {
+    parent::__construct("tag");
+  }
+
+  function display_context($item) {
+    $tag = $this->get("tag");
+
+    $where = array(array("type", "!=", "album"));
+
+    $position = tag::get_position($tag, $item, $where);
+    if ($position > 1) {
+      list ($previous_item, $ignore, $next_item) = $tag->items(3, $position - 2, $where);
+    } else {
+      $previous_item = null;
+      list ($next_item) = $tag->items(1, $position, $where);
+    }
+
+    $root = item::root();
+    return array("position" =>$position,
+                 "previous_item" => $previous_item,
+                 "next_item" =>$next_item,
+                 "sibling_count" => $tag->items_count($where),
+                 "breadcrumbs" => array(
+                   Breadcrumb::instance($root->title, $root->url())->set_first(),
+                   Breadcrumb::instance($tag->name, $tag->url("show={$item->id}")),
+                   Breadcrumb::instance($item->title, $item->url())->set_last()));
+  }
+}
diff --git a/modules/tag/models/tag.php b/modules/tag/models/tag.php
index bb79e707..a7150df8 100644
--- a/modules/tag/models/tag.php
+++ b/modules/tag/models/tag.php
@@ -33,35 +33,39 @@ class Tag_Model_Core extends ORM {
    * Return all viewable items associated with this tag.
    * @param integer  $limit  number of rows to limit result to
    * @param integer  $offset offset in result to start returning rows from
-   * @param string   $type   the type of item (album, photo)
+   * @param string   $where   an array of arrays, each compatible with ORM::where()
    * @return ORM_Iterator
    */
-  public function items($limit=null, $offset=null, $type=null) {
-    $model = ORM::factory("item")
+  public function items($limit=null, $offset=null, $where=array()) {
+    if (is_scalar($where)) {
+      // backwards compatibility
+      $where = array(array("items.type", "=", $where));
+    }
+    return ORM::factory("item")
       ->viewable()
       ->join("items_tags", "items.id", "items_tags.item_id")
-      ->where("items_tags.tag_id", "=", $this->id);
-    if ($type) {
-      $model->where("items.type", "=", $type);
-    }
-    return $model->find_all($limit, $offset);
+      ->where("items_tags.tag_id", "=", $this->id)
+      ->merge_where($where)
+      ->order_by("items.id")
+      ->find_all($limit, $offset);
   }
 
   /**
    * Return the count of all viewable items associated with this tag.
-   * @param string   $type   the type of item (album, photo)
+   * @param string   $where   an array of arrays, each compatible with ORM::where()
    * @return integer
    */
-  public function items_count($type=null) {
-    $model = ORM::factory("item")
+  public function items_count($where=array()) {
+    if (is_scalar($where)) {
+      // backwards compatibility
+      $where = array(array("items.type", "=", $where));
+    }
+    return $model = ORM::factory("item")
       ->viewable()
       ->join("items_tags", "items.id", "items_tags.item_id")
-      ->where("items_tags.tag_id", "=", $this->id);
-
-    if ($type) {
-      $model->where("items.type", "=", $type);
-    }
-    return $model->count_all();
+      ->where("items_tags.tag_id", "=", $this->id)
+      ->merge_where($where)
+      ->count_all();
   }
 
   /**