Implement navigation for photo pages.

controllers/ViewPhoto.php

@@ -22,6 +22,20 @@ class ViewPhoto extends HTMLController
 		if ($exif)
 			$page->setExif($exif);
 
+		// What tag are we browsing?
+		$tag = isset($_GET['in']) ? Tag::fromId($_GET['in']) : null;
+		$id_tag = isset($tag) ? $tag->id_tag : null;
+
+		// Find previous photo in set.
+		$previous_url = $photo->getUrlForPreviousInSet($id_tag);
+		if ($previous_url)
+			$page->setPreviousPhotoUrl($previous_url);
+
+		// ... and the next photo, too.
+		$next_url = $photo->getUrlForNextInSet($id_tag);
+		if ($next_url)
+			$page->setNextPhotoUrl($next_url);
+
 		$this->page->adopt($page);
 		$this->page->setCanonicalUrl($photo->getPageUrl());
 

controllers/ViewPhotoAlbum.php

@@ -79,7 +79,12 @@ class ViewPhotoAlbum extends HTMLController
 		// Load a photo mosaic for the current tag.
 		list($mosaic, $total_count) = $this->getPhotoMosaic($id_tag, $page);
 		if (isset($mosaic))
-			$this->page->adopt(new PhotosIndex($mosaic, Registry::get('user')->isAdmin()));
+		{
+			$index = new PhotosIndex($mosaic, Registry::get('user')->isAdmin());
+			$this->page->adopt($index);
+			if ($id_tag > 1)
+				$index->setUrlSuffix('?in=' . $id_tag);
+		}
 
 		// Make a page index as needed, while we're at it.
 		if ($total_count > self::PER_PAGE)

models/Asset.php

@@ -500,4 +500,70 @@ class Asset
 			WHERE id_asset = {int:id_asset}',
 			$params);
 	}
+
+	public function getUrlForPreviousInSet($id_tag = null)
+	{
+		$row = Registry::get('db')->queryAssoc('
+			SELECT a.*
+			' . (isset($id_tag) ? '
+			FROM assets_tags AS t
+			INNER JOIN assets AS a ON a.id_asset = t.id_asset
+			WHERE t.id_tag = {int:id_tag} AND
+				a.date_captured <= {datetime:date_captured} AND
+				a.id_asset != {int:id_asset}
+			ORDER BY a.date_captured DESC'
+			: '
+			FROM assets AS a
+			WHERE date_captured >= {datetime:date_captured} AND
+				a.id_asset != {int:id_asset}
+			ORDER BY date_captured ASC')
+			 . '
+			LIMIT 1',
+			[
+				'id_asset' => $this->id_asset,
+				'id_tag' => $id_tag,
+				'date_captured' => $this->date_captured,
+			]);
+
+		if ($row)
+		{
+			$obj = self::byRow($row, 'object');
+			return $obj->getPageUrl() . ($id_tag ? '?in=' . $id_tag : '');
+		}
+		else
+			return false;
+	}
+
+	public function getUrlForNextInSet($id_tag = null)
+	{
+		$row = Registry::get('db')->queryAssoc('
+			SELECT a.*
+			' . (isset($id_tag) ? '
+			FROM assets_tags AS t
+			INNER JOIN assets AS a ON a.id_asset = t.id_asset
+			WHERE t.id_tag = {int:id_tag} AND
+				a.date_captured >= {datetime:date_captured} AND
+				a.id_asset != {int:id_asset}
+			ORDER BY a.date_captured ASC'
+			: '
+			FROM assets AS a
+			WHERE date_captured <= {datetime:date_captured} AND
+				a.id_asset != {int:id_asset}
+			ORDER BY date_captured DESC')
+			 . '
+			LIMIT 1',
+			[
+				'id_asset' => $this->id_asset,
+				'id_tag' => $id_tag,
+				'date_captured' => $this->date_captured,
+			]);
+
+		if ($row)
+		{
+			$obj = self::byRow($row, 'object');
+			return $obj->getPageUrl() . ($id_tag ? '?in=' . $id_tag : '');
+		}
+		else
+			return false;
+	}
 }

templates/PhotoPage.php

@@ -10,12 +10,24 @@ class PhotoPage extends SubTemplate
 {
 	private $photo;
 	private $exif;
+	private $previous_photo_url = '';
+	private $next_photo_url = '';
 
 	public function __construct(Image $photo)
 	{
 		$this->photo = $photo;
 	}
 
+	public function setPreviousPhotoUrl($url)
+	{
+		$this->previous_photo_url = $url;
+	}
+
+	public function setNextPhotoUrl($url)
+	{
+		$this->next_photo_url = $url;
+	}
+
 	protected function html_content()
 	{
 		$this->photoNav();
@@ -57,16 +69,16 @@ class PhotoPage extends SubTemplate
 
 	private function photoNav()
 	{
-		if (false) // $previous_post = $this->post->getPreviousPostUrl())
+		if ($this->previous_photo_url)
 			echo '
-				<a href="', $previous_post, '" id="previous_photo"><em>Previous photo</em></a>';
+				<a href="', $this->previous_photo_url, '" id="previous_photo"><em>Previous photo</em></a>';
 		else
 			echo '
 				<span id="previous_photo"><em>Previous photo</em></span>';
 
-		if (false) //$this->post->getNextPostUrl())
+		if ($this->next_photo_url)
 			echo '
-				<a href="', $next_post, '" id="next_photo"><em>Next photo</em></a>';
+				<a href="', $this->next_photo_url, '" id="next_photo"><em>Next photo</em></a>';
 		else
 			echo '
 				<span id="next_photo"><em>Next photo</em></span>';

templates/PhotosIndex.php

@@ -13,6 +13,7 @@ class PhotosIndex extends SubTemplate
 	protected $show_labels;
 	protected $row_limit = 1000;
 	protected $previous_header = '';
+	protected $url_suffix;
 
 	const PANORAMA_WIDTH = 1280;
 	const PANORAMA_HEIGHT = null;
@@ -95,7 +96,7 @@ class PhotosIndex extends SubTemplate
 					<a class="edit" href="', BASEURL, '/editasset/?id=', $image->getId(), '">Edit</a>';
 
 		echo '
-					<a href="', $image->getPageUrl(), '">
+					<a href="', $image->getPageUrl(), $this->url_suffix, '">
 						<img src="', $image->getThumbnailUrl($width, $height, $crop, $fit), '" alt="" title="', $image->getTitle(), '">';
 
 		if ($this->show_labels)
@@ -262,4 +263,9 @@ class PhotosIndex extends SubTemplate
 		echo '
 				</div>';
 	}
+
+	public function setUrlSuffix($suffix)
+	{
+		$this->url_suffix = $suffix;
+	}
 }