/* When a picture is freed, and when it must not be.
 *
 * Removing an image from a note cannot delete the file straight away: the
 * versions from before still show it, and restoring one would find a hole. It
 * goes when the last version holding it is pushed out by newer ones — which is
 * the first moment nothing can ask for it back.
 *
 * Versions expire by count, not by age, so this is testable by simply editing
 * the note enough times. */
import {
  api,
  check,
  createNote,
  createNotebook,
  launch,
  report,
  setTitle,
  typeInEditor,
  withFreshUser,
} from "./lib.mjs";

const PNG =
  "iVBORw0KGgoAAAANSUhEUgAAAAMAAAADCAYAAABWKLW/AAAAFElEQVR42mP8z8BQz0AEYBxVSF+FABJADveWkH6oAAAAAElFTkSuQmCC";

const browser = await launch();
let session;
try {
  session = await withFreshUser(browser, "attlife");
  const p = session.page;
  // Housekeeping is an administrator's to ask for, not the test user's.
  const adminApi = (method, path, body) => api(session.adminPage, method, path, body);
  await createNotebook(p, "Anhang Buch");

  /* Two versions per note, so the picture falls out of history quickly. */
  await p.locator("button").filter({ hasText: "Anhang Buch" }).first().click({ button: "right" });
  await p.waitForTimeout(600);
  await p.getByText("Edit", { exact: true }).click();
  await p.waitForTimeout(600);
  await p.getByLabel("Versions per note").fill("2");
  await p.getByRole("button", { name: /Save|Speichern/ }).click();
  await p.waitForTimeout(1500);

  const notebooks = await api(p, "GET", "/notebooks");
  check(notebooks.body[0].max_versions === 2, "the notebook keeps its own version limit", String(notebooks.body[0].max_versions));

  /* ── a note with a picture ── */
  await p.locator("button").filter({ hasText: "Anhang Buch" }).first().click();
  await p.waitForTimeout(800);
  await createNote(p);
  await setTitle(p, "Mit Bild");
  // Long, so that replacing it later counts as a large deletion. Edits inside
  // five minutes are otherwise folded into one version, and the snapshot holding
  // the picture would never be taken.
  await typeInEditor(p, "Ein ausführlicher Text, der später ersetzt wird. ".repeat(8));
  await p.locator(".ProseMirror").click();
  await p.keyboard.press("Control+End");
  await p.evaluate(async (b64) => {
    const bytes = Uint8Array.from(atob(b64), (c) => c.charCodeAt(0));
    const dt = new DataTransfer();
    dt.items.add(new File([bytes], "dot.png", { type: "image/png" }));
    document
      .querySelector(".ProseMirror")
      .dispatchEvent(new ClipboardEvent("paste", { clipboardData: dt, bubbles: true, cancelable: true }));
  }, PNG);
  await p.waitForTimeout(3500);

  const noteId = (await api(p, "GET", "/notes")).body[0].id;
  const attachmentId = await p.evaluate(() => {
    const img = document.querySelector(".ProseMirror img");
    return img?.getAttribute("data-attachment") || null;
  });
  check(!!attachmentId, "the pasted picture became an attachment", String(attachmentId));

  /* Attachments are content-addressed and served `immutable`, so the browser
   * answers a repeat request from its own cache and would report a deleted file
   * as still present. The cache is right to do that; the question here is what
   * the server holds, so this one asks it directly. */
  const stillThere = async () =>
    (await p.evaluate(async (id) => {
      const r = await fetch(`/api/attachments/${id}`, {
        cache: "no-store",
        headers: { Authorization: "Bearer " + localStorage.getItem("inknote_token") },
      });
      return r.status;
    }, attachmentId)) !== 404;
  check(await stillThere(), "and can be fetched while the note uses it");

  /* ── take it out again ── */
  // Shrinking a note by more than half bypasses the coalescing window, so the
  // state holding the picture is definitely kept as a version.
  await p.locator(".ProseMirror").click();
  await p.keyboard.press("Control+A");
  await p.keyboard.type("Raus.");
  await p.waitForTimeout(2800);

  const body = (await api(p, "GET", `/notes/${noteId}`)).body.content;
  check(!body.includes(attachmentId), "the note no longer refers to it");
  check(
    await stillThere(),
    "but it is kept, because the versions from before still show it — deleting now would leave a hole in the history"
  );

  /** Which of the kept versions still carry the picture. */
  const versionsHolding = async () => {
    const list = (await api(p, "GET", `/notes/${noteId}/versions`)).body;
    const held = await Promise.all(
      list.map(async (v) => {
        const body = (await api(p, "GET", `/notes/${noteId}/versions/${v.id}`)).body.content || "";
        return body.includes(attachmentId) ? v.id : 0;
      })
    );
    return { total: list.length, holding: held.filter(Boolean) };
  };

  const before = await versionsHolding();
  check(
    before.holding.length > 0,
    "a kept version really does still contain the picture — which is why it may not be deleted yet",
    `${before.holding.length} of ${before.total}`
  );

  /* ── push the versions out ── */
  // With a limit of two, a handful of well-separated edits replaces them both.
  /* The churn goes through the API rather than the editor.
   *
   * Typing in the open note races the six-second poller, which can put an
   * earlier body back on screen and produce a version holding the picture again
   * — real behaviour, but noise for this test. What is under test here is the
   * server's bookkeeping: that versions inherit a note's attachments, that the
   * notebook's limit pushes them out, and that freeing follows. Each write grows
   * then shrinks the note, since a large deletion forces a snapshot instead of
   * being folded into the five-minute window.
   */
  const writeBody = async (text) => {
    const doc = { type: "doc", content: [{ type: "paragraph", content: [{ type: "text", text }] }] };
    await api(p, "PUT", `/notes/${noteId}`, { content: JSON.stringify({ v: 2, doc }), attachments: [] });
    await p.waitForTimeout(150);
  };

  let state = before;
  for (let i = 0; i < 8 && state.holding.length > 0; i++) {
    await writeBody(`Fassung ${i + 2}. `.repeat(20));
    await writeBody(`Kurz ${i + 2}.`);
    state = await versionsHolding();
  }

  check(state.total <= 2, "the notebook's limit is what bounds the history", `${state.total} versions`);
  check(
    state.holding.length === 0,
    "editing on eventually pushes every version holding the picture out",
    `${state.holding.length} still hold it`
  );

  /* The sweep runs on a timer in production; asked for directly here, with the
     in-flight grace lowered since nothing is in flight in a finished test. */
  const swept = await adminApi("POST", "/admin/housekeeping", { graceSeconds: 0 });
  check(swept.status === 200, "the sweep can be run on demand", String(swept.status));
  await p.waitForTimeout(1200);
  check(!(await stillThere()), "and the picture is finally released");
} catch (e) {
  check(false, "suite ran to the end", e.message);
} finally {
  await session?.cleanup();
  const code = report();
  await browser.close();
  process.exit(code);
}