import { assertEquals } from "@std/assert";
import type { ConversationId, ConversationView, EntryId } from "@earendil-works/pi-durable";
import { withDom } from "@berry/util/dom.ts";
import { readWhenVisible } from "./read.ts";
import { Scope } from "./ui.ts";

Deno.test("read receipts follow visible settled views without acknowledging unseen turns", async (t) => {
  await withDom(async (window) => {
    let visibility = "visible";
    Object.defineProperty(document, "visibilityState", {
      configurable: true,
      get: () => visibility,
    });
    const scope = new Scope();
    const sent: number[] = [];
    let acknowledge = (_entryId: number) => Promise.resolve();
    const update = readWhenVisible(scope, (entryId) => {
      sent.push(entryId);
      return acknowledge(entryId);
    });
    const view = (id: number, docs: ConversationView["docs"] = {}): ConversationView => ({
      conversation: { id: 1 as ConversationId },
      entries: [
        { id: (id - 1) as EntryId, conversationId: 1 as ConversationId, kind: "pi.user" },
        { id: id as EntryId, conversationId: 1 as ConversationId, kind: "pi.assistant" },
        { id: (id + 1) as EntryId, conversationId: 1 as ConversationId, kind: "berry.event" },
      ],
      docs,
    });
    const settle = () => window.happyDOM.waitUntilComplete();
    const visible = (state: string) => {
      visibility = state;
      document.dispatchEvent(new window.Event("visibilitychange") as unknown as Event);
    };
    try {
      await t.step("working views and queued follow-ups do not send read receipts", async () => {
        update(view(10, { "pi.live": { run: { taskId: 1, inputs: [] } } }));
        update(view(10, { "pi.inbox": { items: [{ id: 1, mode: "followUp", content: "next" }] } }));
        await settle();
        assertEquals(sent, []);
        update(view(10));
        await settle();
        assertEquals(sent, [10]);
        update(view(10));
        await settle();
        assertEquals(sent, [10]);
      });
      await t.step("hidden turns wait until the tab becomes visible", async () => {
        visible("hidden");
        update(view(20));
        await settle();
        assertEquals(sent, [10]);
        visible("visible");
        await settle();
        assertEquals(sent, [10, 20]);
      });
      await t.step(
        "a late read receipt sends only its captured message, then the newer displayed one",
        async () => {
          const pending = Promise.withResolvers<void>();
          acknowledge = (entryId) => entryId === 30 ? pending.promise : Promise.resolve();
          update(view(30));
          update(view(40));
          assertEquals(sent, [10, 20, 30]);
          pending.resolve();
          await settle();
          assertEquals(sent, [10, 20, 30, 40]);
        },
      );
      await t.step(
        "a newer hidden turn is not acknowledged after the older receipt finishes",
        async () => {
          const pending = Promise.withResolvers<void>();
          acknowledge = () => pending.promise;
          update(view(50));
          visible("hidden");
          update(view(60));
          pending.resolve();
          await settle();
          assertEquals(sent, [10, 20, 30, 40, 50]);
          acknowledge = () => Promise.resolve();
          visible("visible");
          await settle();
          assertEquals(sent, [10, 20, 30, 40, 50, 60]);
        },
      );
      await t.step(
        "returning to an earlier branch cannot move the read watermark backwards",
        async () => {
          update(view(20));
          await settle();
          assertEquals(sent, [10, 20, 30, 40, 50, 60]);
        },
      );
      await t.step(
        "leaving the conversation removes visibility acknowledgements and pending work",
        async () => {
          const pending = Promise.withResolvers<void>();
          acknowledge = () => pending.promise;
          update(view(70));
          visible("hidden");
          update(view(80));
          scope.dispose();
          visible("visible");
          pending.resolve();
          await settle();
          update(view(90));
          assertEquals(sent, [10, 20, 30, 40, 50, 60, 70]);
        },
      );
    } finally {
      scope.dispose();
    }
  });
});