import { chromium, type Browser } from "playwright";

import { chromium, type Browser, type Page } from "playwright";

import { afterAll, beforeAll, describe, expect, it } from "vitest";

import {

canRunPlaywrightChromium,

throw new Error(`Timed out waiting for ${count} ${method} requests`);

}

async function chatThreadDistanceFromBottom(page: Page): Promise<number> {

return page.locator(".chat-thread").evaluate((element) => {

const thread = element as HTMLElement;

return Math.round(thread.scrollHeight - thread.scrollTop - thread.clientHeight);

});

}

function chatSessionListResponse() {

return {

count: 2,

}

});

it("scrolls a delayed pending send into view before the ACK resolves", async () => {

const context = await browser.newContext({

locale: "en-US",

serviceWorkers: "block",

viewport: { height: 900, width: 1280 },

});

const page = await context.newPage();

const baseTs = Date.now() - 100_000;

const historyMessages = Array.from({ length: 50 }, (_, index) => ({

content: [

{

text: `History message ${index}\n${"extra transcript line\n".repeat(4)}`,

type: "text",

},

],

role: index % 2 === 0 ? "assistant" : "user",

timestamp: baseTs + index,

}));

const gateway = await installMockGateway(page, { historyMessages });

try {

await page.goto(`${server.baseUrl}chat`);

await page.getByText("History message 49").waitFor({ timeout: 10_000 });

await expect

.poll(() => chatThreadDistanceFromBottom(page), { timeout: 10_000 })

.toBeLessThanOrEqual(4);

await page.locator(".chat-thread").evaluate((element) => {

(element as HTMLElement).scrollTop = 0;

});

await expect

.poll(() => chatThreadDistanceFromBottom(page), { timeout: 10_000 })

.toBeGreaterThan(200);

await gateway.deferNext("chat.send");

const prompt = `pending send should scroll before ack\n${"visible now\n".repeat(6)}`;

await page.locator(".agent-chat__composer-combobox textarea").fill(prompt);

await page.getByRole("button", { name: "Send message" }).click();

const sendRequest = await gateway.waitForRequest("chat.send");

const params = requireRecord(sendRequest.params);

const runId = requireString(params.idempotencyKey, "chat send idempotency key");

await page.locator(".chat-thread").getByText("pending send should scroll").waitFor({

timeout: 10_000,

});

await expect

.poll(() => chatThreadDistanceFromBottom(page), { timeout: 10_000 })

.toBeLessThanOrEqual(4);

await gateway.resolveDeferred("chat.send", { runId, status: "started" });

} finally {

await context.close();

}

});

it("keeps rejected pre-ACK sends visible and restores the draft", async () => {

const context = await browser.newContext({

locale: "en-US",