[Instances] Convert Instance Quest Methods to Repositories (#4012)

* [Instances] Convert Instance Quest Methods to Repositories

# Notes
- Convert `UpdateInstanceTimer()` and `GetInstanceTimerByID()` to repositories.
- Cleanup other instance methods.

* Update questmgr.cpp

common/repositories/instance_list_repository.h

@@ -45,14 +45,41 @@ public:
 
 	// Custom extended repository methods here
 
-	static int UpdateDuration(Database& db, int instance_id, uint32_t new_duration)
+	static int UpdateDuration(Database& db, uint16 instance_id, uint32_t new_duration)
 	{
-		auto results = db.QueryDatabase(fmt::format(
-			"UPDATE {} SET duration = {} WHERE {} = {};",
-			TableName(), new_duration, PrimaryKey(), instance_id
-		));
+		auto results = db.QueryDatabase(
+			fmt::format(
+				"UPDATE `{}` SET `duration` = {} WHERE `{}` = {}",
+				TableName(),
+				new_duration,
+				PrimaryKey(),
+				instance_id
+			)
+		);
 
-		return (results.Success() ? results.RowsAffected() : 0);
+		return results.Success() ? results.RowsAffected() : 0;
+	}
+
+	static uint32 GetRemainingTimeByInstanceID(Database& db, uint16 instance_id)
+	{
+		auto results = db.QueryDatabase(
+			fmt::format(
+				SQL(
+					SELECT ((start_time + duration) - UNIX_TIMESTAMP()) AS `remaining` FROM `{}`
+					WHERE `id` = {}
+				),
+				TableName(),
+				instance_id
+			)
+		);
+
+		if (!results.Success() || !results.RowCount()) {
+			return 0;
+		}
+
+		auto row = results.begin();
+
+		return Strings::ToUnsignedInt(row[0]);
 	}
 };