1 files changed, 44 insertions, 0 deletions
diff --git a/packages/backend/src/misc/id/aidx.ts b/packages/backend/src/misc/id/aidx.ts
new file mode 100644
index 0000000000..5b031ea4c0
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+++ b/packages/backend/src/misc/id/aidx.ts
@@ -0,0 +1,44 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and other misskey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+// AIDX
+// 長さ8の[2000年1月1日からの経過ミリ秒をbase36でエンコードしたもの] + 長さ4の[個体ID] + 長さ4の[カウンタ]
+// (c) mei23
+// https://misskey.m544.net/notes/71899acdcc9859ec5708ac24
+
+import { customAlphabet } from 'nanoid';
+
+export const aidxRegExp = /^[0-9a-z]{16}$/;
+
+const TIME2000 = 946684800000;
+const TIME_LENGTH = 8;
+const NODE_LENGTH = 4;
+const NOISE_LENGTH = 4;
+
+const nodeId = customAlphabet('0123456789abcdefghijklmnopqrstuvwxyz', NODE_LENGTH)();
+let counter = 0;
+
+function getTime(time: number): string {
+	time = time - TIME2000;
+	if (time < 0) time = 0;
+
+	return time.toString(36).padStart(TIME_LENGTH, '0').slice(-TIME_LENGTH);
+}
+
+function getNoise(): string {
+	return counter.toString(36).padStart(NOISE_LENGTH, '0').slice(-NOISE_LENGTH);
+}
+
+export function genAidx(date: Date): string {
+	const t = date.getTime();
+	if (isNaN(t)) throw new Error('Failed to create AIDX: Invalid Date');
+	counter++;
+	return getTime(t) + nodeId + getNoise();
+}
+
+export function parseAidx(id: string): { date: Date; } {
+	const time = parseInt(id.slice(0, TIME_LENGTH), 36) + TIME2000;
+	return { date: new Date(time) };
+}