Refactor entry-to-GReader API format (#4490)

* Refactor entry to GReader API format
Some code was copied in two locations and not completely uniform.
Cleaning of related variables and functions (e.g. better types for entries and categories as objects vs. as IDs).
Usecase: I need to call the same GReader-compatible serialization from an extension

* Fixed some edge cases

* Keep summary instead of content
`summary` and `content` seems to be used interchangeably in the Google Reader API. We have been using `summary` for our client API and  `content` in our export/import, so stick to that.

1 files changed, 129 insertions, 19 deletions

diff --git a/app/Models/Entry.php b/app/Models/Entry.php
index 72e59e38c..e383f9060 100644
--- a/app/Models/Entry.php
+++ b/app/Models/Entry.php
@@ -31,6 +31,7 @@ class FreshRSS_Entry extends Minz_Model {
 	 * @var bool|null
 	 */
 	private $is_read;
+	/** @var bool|null */
 	private $is_favorite;
 
 	/**
@@ -213,17 +214,22 @@ class FreshRSS_Entry extends Minz_Model {
 	public function isFavorite() {
 		return $this->is_favorite;
 	}
-	public function feed($object = false) {
-		if ($object) {
-			if ($this->feed == null) {
-				$feedDAO = FreshRSS_Factory::createFeedDao();
-				$this->feed = $feedDAO->searchById($this->feedId);
-			}
-			return $this->feed;
-		} else {
-			return $this->feedId;
+
+	/**
+	 * @return FreshRSS_Feed|null|false
+	 */
+	public function feed() {
+		if ($this->feed === null) {
+			$feedDAO = FreshRSS_Factory::createFeedDao();
+			$this->feed = $feedDAO->searchById($this->feedId);
 		}
+		return $this->feed;
 	}
+
+	public function feedId(): int {
+		return $this->feedId;
+	}
+
 	public function tags($asString = false) {
 		if ($asString) {
 			return $this->tags == null ? '' : '#' . implode(' #', $this->tags);
@@ -331,18 +337,21 @@ class FreshRSS_Entry extends Minz_Model {
 		$this->is_read = $value === null ? null : (bool)$value;
 	}
 	public function _isFavorite($value) {
-		$this->is_favorite = $value;
+		$this->is_favorite = $value === null ? null : (bool)$value;
 	}
-	public function _feed($value) {
-		if ($value != null) {
-			$this->feed = $value;
-			$this->feedId = $this->feed->id();
-		}
+
+	/** @param FreshRSS_Feed|null $feed */
+	public function _feed($feed) {
+		$this->feed = $feed;
+		$this->feedId = $this->feed == null ? 0 : $this->feed->id();
 	}
-	private function _feedId($value) {
+
+	/** @param int|string $id */
+	private function _feedId($id) {
 		$this->feed = null;
-		$this->feedId = intval($value);
+		$this->feedId = intval($id);
 	}
+
 	public function _tags($value) {
 		$this->hash = '';
 		if (!is_array($value)) {
@@ -558,7 +567,7 @@ class FreshRSS_Entry extends Minz_Model {
 	public function loadCompleteContent(bool $force = false): bool {
 		// Gestion du contenu
 		// Trying to fetch full article content even when feeds do not propose it
-		$feed = $this->feed(true);
+		$feed = $this->feed();
 		if ($feed != null && trim($feed->pathEntries()) != '') {
 			$entryDAO = FreshRSS_Factory::createEntryDao();
 			$entry = $force ? null : $entryDAO->searchByGuid($this->feedId, $this->guid);
@@ -613,9 +622,110 @@ class FreshRSS_Entry extends Minz_Model {
 			'hash' => $this->hash(),
 			'is_read' => $this->isRead(),
 			'is_favorite' => $this->isFavorite(),
-			'id_feed' => $this->feed(),
+			'id_feed' => $this->feedId(),
 			'tags' => $this->tags(true),
 			'attributes' => $this->attributes(),
 		);
 	}
+
+	/**
+	 * Integer format conversion for Google Reader API format
+	 * @param string|int $dec Decimal number
+	 * @return string 64-bit hexa http://code.google.com/p/google-reader-api/wiki/ItemId
+	 */
+	private static function dec2hex($dec): string {
+		return PHP_INT_SIZE < 8 ? // 32-bit ?
+			str_pad(gmp_strval(gmp_init($dec, 10), 16), 16, '0', STR_PAD_LEFT) :
+			str_pad(dechex($dec), 16, '0', STR_PAD_LEFT);
+	}
+
+	/**
+	 * N.B.: To avoid expensive lookups, ensure to set `$entry->_feed($feed)` before calling this function.
+	 * N.B.: You might have to populate `$entry->_tags()` prior to calling this function.
+	 * @param string $mode Set to `'compat'` to use an alternative Unicode representation for problematic HTML special characters not decoded by some clients;
+	 * 	set to `'freshrss'` for using FreshRSS additions for internal use (e.g. export/import).
+	 * @return array<string,mixed> A representation of this entry in a format compatible with Google Reader API
+	 */
+	public function toGReader(string $mode = ''): array {
+
+		$feed = $this->feed();
+		$category = $feed == null ? null : $feed->category();
+
+		$item = [
+			'id' => 'tag:google.com,2005:reader/item/' . self::dec2hex($this->id()),
+			'crawlTimeMsec' => substr($this->dateAdded(true, true), 0, -3),
+			'timestampUsec' => '' . $this->dateAdded(true, true), //EasyRSS & Reeder
+			'published' => $this->date(true),
+			// 'updated' => $this->date(true),
+			'title' => $this->title(),
+			'summary' => ['content' => $this->content()],
+			'canonical' => [
+				['href' => htmlspecialchars_decode($this->link(), ENT_QUOTES)],
+			],
+			'alternate' => [
+				[
+					'href' => htmlspecialchars_decode($this->link(), ENT_QUOTES),
+					'type' => 'text/html',
+				],
+			],
+			'categories' => [
+				'user/-/state/com.google/reading-list',
+			],
+			'origin' => [
+				'streamId' => 'feed/' . $this->feedId,
+			],
+		];
+		if ($mode === 'compat') {
+			$item['title'] = escapeToUnicodeAlternative($this->title(), false);
+		} elseif ($mode === 'freshrss') {
+			$item['guid'] = $this->guid();
+			unset($item['summary']);
+			$item['content'] = ['content' => $this->content()];
+		}
+		if ($category != null && $mode !== 'freshrss') {
+			$item['categories'][] = 'user/-/label/' . htmlspecialchars_decode($category->name(), ENT_QUOTES);
+		}
+		if ($feed != null) {
+			$item['origin']['htmlUrl'] = htmlspecialchars_decode($feed->website());
+			$item['origin']['title'] = $feed->name();	//EasyRSS
+			if ($mode === 'compat') {
+				$item['origin']['title'] = escapeToUnicodeAlternative($feed->name(), true);
+			} elseif ($mode === 'freshrss') {
+				$item['origin']['feedUrl'] = htmlspecialchars_decode($feed->url());
+			}
+		}
+		foreach ($this->enclosures() as $enclosure) {
+			if (!empty($enclosure['url']) && !empty($enclosure['type'])) {
+				$media = [
+						'href' => $enclosure['url'],
+						'type' => $enclosure['type'],
+					];
+				if (!empty($enclosure['length'])) {
+					$media['length'] = intval($enclosure['length']);
+				}
+				$item['enclosure'][] = $media;
+			}
+		}
+		$author = $this->authors(true);
+		$author = trim($author, '; ');
+		if ($author != '') {
+			if ($mode === 'compat') {
+				$item['author'] = escapeToUnicodeAlternative($author, false);
+			} else {
+				$item['author'] = $author;
+			}
+		}
+		if ($this->isRead()) {
+			$item['categories'][] = 'user/-/state/com.google/read';
+		} elseif ($mode === 'freshrss') {
+			$item['categories'][] = 'user/-/state/com.google/unread';
+		}
+		if ($this->isFavorite()) {
+			$item['categories'][] = 'user/-/state/com.google/starred';
+		}
+		foreach ($this->tags() as $tagName) {
+			$item['categories'][] = 'user/-/label/' . htmlspecialchars_decode($tagName, ENT_QUOTES);
+		}
+		return $item;
+	}
 }