import { assertEquals } from "@std/assert";
import { withBerry } from "./testing.ts";

Deno.test("a first snapshot shows as its older entries arrive, and a later one only once it is whole", async () => {
  await withBerry(async ({ server: { deliver } }) => {
    const { watch } = await import("./client.ts");
    deliver({ t: "ready" });
    const topic = "conversation:a";
    const seen: number[][] = [];
    const release = watch<{ entries: { id: number }[] }>(topic, ({ entries }) => {
      seen.push(entries.map((entry) => entry.id));
    });
    const entries = (...ids: number[]) => ids.map((id) => ({ id }));
    deliver({ t: "snapshot", topic, value: { entries: entries(3) }, older: 2 });
    deliver({ t: "older", topic, entries: entries(2) });
    deliver({ t: "older", topic, entries: entries(1) });
    assertEquals(seen, [[3], [2, 3], [1, 2, 3]]);

    // as after a reconnect: the topic is asked for again, and has what it had meanwhile
    deliver({ t: "ready" });
    deliver({ t: "snapshot", topic, value: { entries: entries(4) }, older: 3 });
    deliver({ t: "older", topic, entries: entries(2, 3) });
    assertEquals(seen.length, 3);
    deliver({ t: "older", topic, entries: entries(1) });
    assertEquals(seen.at(-1), [1, 2, 3, 4]);
    assertEquals(seen.length, 4);
    release();
  });
});