import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
import { render, screen } from "@testing-library/react";
import type { ReactNode } from "react";
import { describe, expect, it } from "vitest";

import { ThreadView } from "../components/thread/ThreadView";
import { I18nProvider } from "../i18n";
import { ThemeProvider } from "../lib/theme";
import type { MessageEnvelope } from "../lib/types";

function msg(id: string, minutes: number, unread = false): MessageEnvelope {
  return {
    id,
    account_id: "acc",
    mailbox_id: "mb",
    thread_id: "t",
    subject: "Subject",
    from_addr: [{ name: `Sender ${id}`, email: `${id}@x.com` }],
    to_addr: [],
    cc_addr: [],
    bcc_addr: [],
    date: new Date(2026, 0, 1, 12, minutes).toISOString(),
    flags: unread ? [] : ["\\Seen"],
    is_unread: unread,
    is_starred: false,
    has_attachments: false,
    has_remote_images: false,
    images_allowed: false,
    size_bytes: 1024,
    snippet: `snippet ${id}`,
    also_in_account_ids: [],
  };
}

// ASC input always (SPEC §9.4): oldest first.
const MESSAGES = [msg("a", 0), msg("b", 1), msg("c", 2)];

function wrap(children: ReactNode) {
  const qc = new QueryClient({ defaultOptions: { queries: { retry: false } } });
  return (
    <I18nProvider>
      <ThemeProvider>
        <QueryClientProvider client={qc}>{children}</QueryClientProvider>
      </ThemeProvider>
    </I18nProvider>
  );
}

function renderThread(order: "asc" | "desc") {
  return render(wrap(<ThreadView subject="Subject" messages={MESSAGES} order={order} />));
}

function messageOrder(): string[] {
  return screen.getAllByTestId("message").map((el) => el.getAttribute("data-message-id")!);
}

describe("ThreadView direction-agnostic layout (SPEC §9.4)", () => {
  it("renders oldest-first when order=asc", () => {
    renderThread("asc");
    expect(messageOrder()).toEqual(["a", "b", "c"]);
  });

  it("renders newest-first when order=desc", () => {
    renderThread("desc");
    expect(messageOrder()).toEqual(["c", "b", "a"]);
  });

  it("attaches the composer directly after the newest message in both orders", () => {
    // asc: newest 'c' is last -> composer at the very bottom
    const asc = renderThread("asc");
    const ascNodes = Array.from(
      asc.container.querySelectorAll('[data-testid="message"],[data-testid="composer-anchor"]'),
    );
    const ascComposerIdx = ascNodes.findIndex(
      (n) => n.getAttribute("data-testid") === "composer-anchor",
    );
    const ascNewestIdx = ascNodes.findIndex((n) => n.getAttribute("data-message-id") === "c");
    expect(ascComposerIdx).toBe(ascNewestIdx + 1);
    expect(ascComposerIdx).toBe(ascNodes.length - 1); // bottom

    // desc: newest 'c' is first -> composer right after it (top), above older
    const desc = renderThread("desc");
    const descNodes = Array.from(
      desc.container.querySelectorAll('[data-testid="message"],[data-testid="composer-anchor"]'),
    );
    const descComposerIdx = descNodes.findIndex(
      (n) => n.getAttribute("data-testid") === "composer-anchor",
    );
    const descNewestIdx = descNodes.findIndex((n) => n.getAttribute("data-message-id") === "c");
    expect(descComposerIdx).toBe(descNewestIdx + 1);
    expect(descNewestIdx).toBe(0); // newest at top
  });

  it("keeps unread messages expanded but read (non-newest) ones collapsed", () => {
    const messages = [msg("a", 0), msg("b", 1, true), msg("c", 2)];
    const { container } = render(wrap(<ThreadView subject="Subject" messages={messages} order="asc" />));
    // An expanded message renders a MessageBody (iframe/loading/error); collapsed does not.
    const aNode = container.querySelector('[data-message-id="a"]') as HTMLElement;
    const bNode = container.querySelector('[data-message-id="b"]') as HTMLElement;
    const hasBody = (el: HTMLElement) =>
      el.querySelector("iframe") !== null ||
      /Loading thread|Couldn't load/i.test(el.textContent ?? "");
    expect(hasBody(aNode)).toBe(false); // read, not newest -> collapsed
    expect(hasBody(bNode)).toBe(true); // unread -> expanded
    expect(container).toBeTruthy();
  });
});