/* Importing and reading a PDF.
 *
 * The interesting parts are not that a canvas appears: it is that the library
 * stays out of the main bundle until a PDF is opened, that the pages come out at
 * the right proportions, and that a document read once survives without the
 * network — the offline promise is the whole reason the bytes are cached. */
import { writeFileSync } from "node:fs";
import { check, createNotebook, launch, report, withFreshUser } from "./lib.mjs";

const PDF_PATH = "/tmp/e2e-test.pdf";

/** A two-page PDF built here, so the suite depends on no fixture file. */
function writeTestPdf() {
  const objs = [
    "<< /Type /Catalog /Pages 2 0 R >>",
    "<< /Type /Pages /Kids [3 0 R 5 0 R] /Count 2 >>",
    "<< /Type /Page /Parent 2 0 R /MediaBox [0 0 595 842] /Contents 4 0 R /Resources << /Font << /F1 7 0 R >> >> >>",
    null, // stream, filled below
    "<< /Type /Page /Parent 2 0 R /MediaBox [0 0 842 595] /Contents 6 0 R /Resources << /Font << /F1 7 0 R >> >> >>",
    null,
    "<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>",
  ];
  const s1 = "BT /F1 24 Tf 72 760 Td (Seite eins Zebrastreifen) Tj ET";
  const s2 = "BT /F1 24 Tf 72 520 Td (Seite zwei Dichtung) Tj ET";
  objs[3] = `<< /Length ${s1.length} >>\nstream\n${s1}\nendstream`;
  objs[5] = `<< /Length ${s2.length} >>\nstream\n${s2}\nendstream`;

  let out = "%PDF-1.4\n";
  const offsets = [];
  objs.forEach((o, i) => {
    offsets.push(out.length);
    out += `${i + 1} 0 obj\n${o}\nendobj\n`;
  });
  const xref = out.length;
  out += `xref\n0 ${objs.length + 1}\n0000000000 65535 f \n`;
  for (const off of offsets) out += `${String(off).padStart(10, "0")} 00000 n \n`;
  out += `trailer\n<< /Size ${objs.length + 1} /Root 1 0 R >>\nstartxref\n${xref}\n%%EOF\n`;
  writeFileSync(PDF_PATH, out, "latin1");
}

const browser = await launch();
let session;
try {
  writeTestPdf();
  session = await withFreshUser(browser, "pdf");
  const p = session.page;

  /* The library must not be in the bundle everyone downloads. */
  const scriptsBefore = await p.evaluate(() =>
    performance.getEntriesByType("resource").map((r) => r.name)
  );
  check(
    !scriptsBefore.some((u) => /pdf[.-]/i.test(u)),
    "pdf.js is not loaded before a PDF is opened",
    scriptsBefore.filter((u) => /pdf/i.test(u)).join(", ") || "none"
  );

  await createNotebook(p, "PDF Buch");

  /* ── import ── */
  const chooser = p.waitForEvent("filechooser");
  await p.getByTitle("Import PDF").click();
  await (await chooser).setFiles(PDF_PATH);
  await p.waitForTimeout(4000);

  check((await p.locator("[data-pdf-page]").count()) > 0, "the document is shown after importing");
  check(
    (await p.locator("[data-pdf-position]").innerText()).includes("/ 2"),
    "both pages are counted",
    await p.locator("[data-pdf-position]").innerText()
  );
  await p.screenshot({ path: "/out/pdf-imported.png" });

  /* ── proportions ── */
  const boxes = await p.$$eval("[data-pdf-page]", (els) =>
    els.map((e) => ({ w: e.offsetWidth, h: e.offsetHeight }))
  );
  check(boxes.length === 2, "both pages are laid out", JSON.stringify(boxes));
  // Page one is A4 portrait (595×842), page two the same turned on its side.
  const ratio1 = boxes[0].h / boxes[0].w;
  const ratio2 = boxes[1].h / boxes[1].w;
  check(Math.abs(ratio1 - 842 / 595) < 0.05, "the portrait page keeps its proportions", ratio1.toFixed(2));
  check(Math.abs(ratio2 - 595 / 842) < 0.05, "the landscape page is not stretched to match", ratio2.toFixed(2));

  /* ── something was actually painted ── */
  const inkedPixels = await p.evaluate(() => {
    const c = document.querySelector("[data-pdf-page] canvas");
    if (!c) return -1;
    const ctx = c.getContext("2d");
    const d = ctx.getImageData(0, 0, c.width, Math.min(c.height, 400)).data;
    let dark = 0;
    for (let i = 0; i < d.length; i += 4) if (d[i] < 200) dark++;
    return dark;
  });
  check(inkedPixels > 50, "the page has actual content drawn on it", `${inkedPixels} dark pixels`);

  const loadedAfter = await p.evaluate(() => performance.getEntriesByType("resource").map((r) => r.name));
  check(
    loadedAfter.some((u) => /pdf.*\.js|pdf\.worker/i.test(u)),
    "pdf.js was fetched only once it was needed"
  );

  /* ── drawing on a page ── */
  const inkOnPage = (n) =>
    p.evaluate((page) => {
      const c = document.querySelector(`[data-pdf-ink="${page}"]`);
      if (!c) return -1;
      const d = c.getContext("2d").getImageData(0, 0, c.width, c.height).data;
      let painted = 0;
      for (let i = 3; i < d.length; i += 4) if (d[i] > 40) painted++;
      return painted;
    }, n);

  /** Draws a line across the page in fractions of its box, then waits for the save. */
  const drawOn = async (pageNo, x1, y1, x2, y2) => {
    const box = await p.locator(`[data-pdf-page="${pageNo}"]`).boundingBox();
    await p.mouse.move(box.x + box.width * x1, box.y + box.height * y1);
    await p.mouse.down();
    await p.mouse.move(box.x + box.width * x2, box.y + box.height * y2, { steps: 14 });
    await p.mouse.up();
    await p.waitForTimeout(1600);
  };

  check((await inkOnPage(1)) === 0, "no ink before anything is drawn");
  await p.locator("[data-pdf-mode]").click();
  check((await p.locator('[data-pdf-mode="draw"]').count()) === 1, "drawing mode can be switched on");

  await drawOn(1, 0.2, 0.25, 0.7, 0.3);
  const inkedFirst = await inkOnPage(1);
  check(inkedFirst > 100, "the stroke appears on the page", `${inkedFirst} painted pixels`);
  check((await inkOnPage(2)) === 0, "and only on the page it was drawn on");
  await p.screenshot({ path: "/out/pdf-drawn.png" });

  /* Where the stroke sits relative to the page, so zoom can be compared against it. */
  const inkBounds = (n) =>
    p.evaluate((page) => {
      const c = document.querySelector(`[data-pdf-ink="${page}"]`);
      const d = c.getContext("2d").getImageData(0, 0, c.width, c.height).data;
      let minX = 1e9, maxX = -1, minY = 1e9, maxY = -1;
      for (let i = 3, px = 0; i < d.length; i += 4, px++) {
        if (d[i] <= 40) continue;
        const x = px % c.width, y = (px / c.width) | 0;
        if (x < minX) minX = x;
        if (x > maxX) maxX = x;
        if (y < minY) minY = y;
        if (y > maxY) maxY = y;
      }
      // As fractions of the canvas, so they can be compared across zoom levels.
      return { x: minX / c.width, y: minY / c.height, w: (maxX - minX) / c.width, h: (maxY - minY) / c.height };
    }, n);

  const before = await inkBounds(1);
  await p.getByTitle("Größer").click();
  await p.waitForTimeout(2500);
  const after = await inkBounds(1);
  const drift = Math.max(Math.abs(before.x - after.x), Math.abs(before.y - after.y), Math.abs(before.w - after.w));
  check(drift < 0.02, "the stroke stays on the same spot when zoomed", `drift ${drift.toFixed(3)}`);
  await p.getByTitle("Kleiner").click();
  await p.waitForTimeout(1500);

  /* ── hiding it ── */
  await p.locator("[data-pdf-hide-ink]").click();
  await p.waitForTimeout(600);
  check((await inkOnPage(1)) >= 0, "hiding the drawing leaves the document readable");
  const hiddenOpacity = await p.locator('[data-pdf-ink="1"]').evaluate((c) => getComputedStyle(c).opacity);
  check(hiddenOpacity === "0", "the ink layer is hidden, not erased", hiddenOpacity);
  await p.locator("[data-pdf-hide-ink]").click();
  await p.waitForTimeout(600);

  /* ── it survives ── */
  await p.reload({ waitUntil: "networkidle" });
  await p.waitForTimeout(2500);
  await p.locator("button").filter({ hasText: "PDF Buch" }).first().click();
  await p.waitForTimeout(1200);
  await p.locator("[data-note-row]").first().click();
  await p.waitForTimeout(4500);
  const afterReload = await inkOnPage(1);
  check(afterReload > 100, "the stroke survived a reload", `${afterReload} painted pixels`);

  /* ── it must not be undone by the background poller ── */
  await p.waitForTimeout(9000);
  check((await inkOnPage(1)) > 100, "and is still there after the sync poller has run");

  /* ── it stays readable offline ── */
  // A reload lands on the dashboard, which has no note list; the notebook has
  // to be opened first before a row exists to click.
  const reopen = async () => {
    await p.locator("button").filter({ hasText: "PDF Buch" }).first().click();
    await p.waitForTimeout(1200);
    await p.locator("[data-note-row]").first().click();
    await p.waitForTimeout(4000);
  };

  await p.reload({ waitUntil: "networkidle" });
  await p.waitForTimeout(2500);
  await reopen();
  check((await p.locator("[data-pdf-page]").count()) > 0, "the document reopens after a reload");

  await p.context().setOffline(true);
  await p.reload({ waitUntil: "domcontentloaded" });
  await p.waitForTimeout(3000);
  await reopen();
  check(
    (await p.locator("[data-pdf-page]").count()) > 0,
    "and still opens with the network switched off"
  );
  await p.screenshot({ path: "/out/pdf-offline.png" });
  await p.context().setOffline(false);
} catch (e) {
  check(false, "suite ran to the end", e.message);
} finally {
  await session?.cleanup();
  const code = report();
  await browser.close();
  process.exit(code);
}