sync

packages/opencode/src/id/id.ts

@@ -0,0 +1,74 @@
+import { z } from "zod";
+import { randomBytes } from "crypto";
+
+export namespace Identifier {
+  const prefixes = {
+    session: "ses",
+    message: "msg",
+  } as const;
+
+  export function schema(prefix: keyof typeof prefixes) {
+    return z.string().startsWith(prefixes[prefix]);
+  }
+
+  const LENGTH = 26;
+
+  // State for monotonic ID generation
+  let lastTimestamp = 0;
+  let counter = 0;
+
+  export function ascending(prefix: keyof typeof prefixes, given?: string) {
+    return generateID(prefix, false, given);
+  }
+
+  export function descending(prefix: keyof typeof prefixes, given?: string) {
+    return generateID(prefix, true, given);
+  }
+
+  function generateID(
+    prefix: keyof typeof prefixes,
+    descending: boolean,
+    given?: string,
+  ): string {
+    if (!given) {
+      return generateNewID(prefix, descending);
+    }
+    
+    if (!given.startsWith(prefixes[prefix])) {
+      throw new Error(`ID ${given} does not start with ${prefixes[prefix]}`);
+    }
+    return given;
+  }
+
+  function generateNewID(
+    prefix: keyof typeof prefixes,
+    descending: boolean,
+  ): string {
+    const currentTimestamp = Date.now();
+
+    if (currentTimestamp !== lastTimestamp) {
+      lastTimestamp = currentTimestamp;
+      counter = 0;
+    }
+    counter++;
+
+    let now = BigInt(currentTimestamp) * BigInt(0x1000) + BigInt(counter);
+
+    now = descending ? ~now : now;
+
+    const timeBytes = Buffer.alloc(6);
+    for (let i = 0; i < 6; i++) {
+      timeBytes[i] = Number((now >> BigInt(40 - 8 * i)) & BigInt(0xff));
+    }
+
+    const randLength = (LENGTH - 12) / 2;
+    const random = randomBytes(randLength);
+
+    return (
+      prefixes[prefix] +
+      "_" +
+      timeBytes.toString("hex") +
+      random.toString("hex")
+    );
+  }
+}