[chore] much improved paging package (#2182)

internal/paging/order.go

@@ -0,0 +1,55 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package paging
+
+// Order represents the order an input
+// page should be sorted and paged in.
+//
+// NOTE: this does not effect the order of returned
+// API results, which must always be in descending
+// order. This behaviour is confusing, but we adopt
+// it to stay inline with Mastodon API expectations.
+type Order int
+
+const (
+	_default Order = iota
+	OrderDescending
+	OrderAscending
+)
+
+// Ascending returns whether this Order is ascending.
+func (i Order) Ascending() bool {
+	return i == OrderAscending
+}
+
+// Descending returns whether this Order is descending.
+func (i Order) Descending() bool {
+	return i == OrderDescending
+}
+
+// String returns a string representation of Order.
+func (i Order) String() string {
+	switch i {
+	case OrderDescending:
+		return "Descending"
+	case OrderAscending:
+		return "Ascending"
+	default:
+		return "not-specified"
+	}
+}