Add cover art database

Co-authored-by: Job Curtis <job.curtis@gmail.com>
Co-authored-by: Alex Cabal <alex@standardebooks.org>

lib/ArtworkTag.php

@@ -0,0 +1,66 @@
+<?
+
+class ArtworkTag extends Tag{
+	// *******
+	// GETTERS
+	// *******
+
+	/**
+	 * @return string
+	 */
+	protected function GetUrl(): string{
+		if($this->_Url === null){
+			$this->_Url = '/artworks?query=' . Formatter::MakeUrlSafe($this->Name);
+		}
+
+		return $this->_Url;
+	}
+
+	// *******
+	// METHODS
+	// *******
+	protected function Validate(): void{
+		$error = new Exceptions\ValidationException();
+
+		if($this->Name === null || strlen($this->Name) === 0){
+			$error->Add(new Exceptions\InvalidArtworkTagException());
+		}
+
+		if($this->Url === null || strlen($this->Url) === 0){
+			$error->Add(new Exceptions\InvalidArtworkTagException());
+		}
+
+		if($error->HasExceptions){
+			throw $error;
+		}
+	}
+
+	public function Create(): void{
+		$this->Validate();
+
+		Db::Query('
+			INSERT into Tags (Name)
+			values (?)
+		', [$this->Name]);
+		$this->TagId = Db::GetLastInsertedId();
+	}
+
+	/**
+	 * @throws \Exceptions\ValidationException
+	 */
+	public static function GetOrCreate(ArtworkTag $artworkTag): ArtworkTag{
+		$result = Db::Query('
+				SELECT *
+				from Tags
+				where Name = ?
+			', [$artworkTag->Name], 'ArtworkTag');
+
+		if(isset($result[0])){
+			return $result[0];
+		}
+		else{
+			$artworkTag->Create();
+			return $artworkTag;
+		}
+	}
+}