// PDF Editor — the page. A full Theseus tab, opened through the "open-tab"
// capability, talking to the add-on's Node half over window.silentmode.
//
// Boot order matters: pdf.js's viewer components are published as a bundle
// that reads its API off globalThis.pdfjsLib rather than importing it, so the
// core has to be imported and parked on the global BEFORE the components
// bundle is pulled in.
//
// Find is deliberately absent from this file. Theseus captures Ctrl+F at the
// app level (main.js's before-input-event handler) and drives Chromium's own
// findInPage over the tab — so the browser's find bar already searches this
// document, with the count and next/previous the user knows from every other
// page. A second find UI inside the tab would be the worse one. What this file
// owes that arrangement is a text layer for every page, drawn or not, which is
// why lib/view.js keeps its own (see the comment there).

import { DocModel } from "./lib/model.js";
import { PageStrip } from "./lib/view.js";
import { Rail } from "./lib/rail.js";
import { Tools } from "./lib/tools.js";
import { SignaturePad } from "./lib/signature.js";
import { buildPdf, unencodableStamps } from "./lib/save.js";
import { boundsOf, clampFont } from "./lib/shape.js";

const $ = (id) => document.getElementById(id);
const sm = window.silentmode || null;

const FLATTEN_DPI = 150;   // raster resolution when rebuilding a redacted page

// ---- boot pdf.js ------------------------------------------------------
let pdfjsLib = null;
async function bootPdfjs() {
  if (pdfjsLib) return pdfjsLib;
  const core = await import("./vendor/pdfjs/pdf.min.mjs");
  core.GlobalWorkerOptions.workerSrc = new URL("./vendor/pdfjs/pdf.worker.min.mjs", import.meta.url).href;
  // pdf_viewer.mjs is built with the core as an external and reads it off the
  // global at module-evaluation time, so this assignment has to happen first.
  globalThis.pdfjsLib = core;
  const viewer = await import("./vendor/pdfjs/web/pdf_viewer.mjs");
  // A module namespace object is frozen, so the components go on a wrapper
  // rather than onto `core` itself.
  pdfjsLib = {
    getDocument: core.getDocument,
    TextLayer: core.TextLayer,
    setLayerDimensions: core.setLayerDimensions,
    AnnotationMode: core.AnnotationMode,
    viewer,
  };
  return pdfjsLib;
}

// ---- session ----------------------------------------------------------
const session = {
  bytes: null,        // Uint8Array, the untouched original
  pdf: null,          // pdf.js PDFDocumentProxy
  model: null,
  strip: null,
  rail: null,
  tools: null,
  scratchId: null,    // set when the document came from the add-on's scratch dir
  name: "document.pdf",
};

// ---- chrome -----------------------------------------------------------
function toast(msg, err) {
  const t = $("toast");
  t.textContent = msg;
  t.classList.toggle("err", !!err);
  t.classList.add("on");
  clearTimeout(toast._t);
  toast._t = setTimeout(() => t.classList.remove("on"), err ? 4200 : 2000);
}
function status(msg, err) {
  const s = $("status");
  s.textContent = msg;
  s.classList.toggle("err", !!err);
}
function setBusy(on, why) {
  document.body.dataset.busy = on ? "1" : "";
  if (on && why) status(why);
}

function paintChrome() {
  const m = session.model;
  $("save").disabled = !m;
  $("undo").disabled = !m || !m.canUndo();
  $("redo").disabled = !m || !m.canRedo();
  const nameEl = $("docname");
  nameEl.textContent = session.name || "No document";
  nameEl.classList.toggle("dirty", !!m && m.isDirty());
  document.body.dataset.empty = m ? "" : "1";
}

function paintPageInfo() {
  const m = session.model, strip = session.strip;
  if (!m || !strip) { $("pageinfo").textContent = ""; return; }
  const vis = m.visible();
  const at = strip.current ? vis.indexOf(strip.current) + 1 : 1;
  const pct = Math.round(strip.scale * 100);
  $("pageinfo").textContent = `Page ${at} of ${vis.length} · ${pct}%`;
}

// ---- modals -----------------------------------------------------------
let modalResolve = null;
function openModal(id) {
  for (const m of document.querySelectorAll(".modal")) m.hidden = true;
  $(id).hidden = false;
  $("scrim").hidden = false;
  return new Promise((res) => { modalResolve = res; });
}
function closeModal(value) {
  $("scrim").hidden = true;
  for (const m of document.querySelectorAll(".modal")) m.hidden = true;
  const r = modalResolve; modalResolve = null;
  r?.(value);
}
$("scrim").addEventListener("pointerdown", (e) => { if (e.target === $("scrim")) closeModal(null); });

// ---- loading ----------------------------------------------------------
async function loadBytes(bytes, name, scratchId = null) {
  if (session.pdf) await teardown();
  // pdf.js TRANSFERS the buffer it is given to its worker, which detaches our
  // view of it — and pdf-lib needs those same bytes at save time. Keep the
  // original and hand the worker a copy.
  session.bytes = bytes;
  session.name = name;
  session.scratchId = scratchId;
  setBusy(true, "Opening…");
  const lib = await bootPdfjs();
  const task = lib.getDocument({
    data: bytes.slice(),
    standardFontDataUrl: "vendor/pdfjs/standard_fonts/",
    wasmUrl: "vendor/pdfjs/wasm/",
    iccUrl: "vendor/pdfjs/iccs/",
    // XFA forms render best-effort. pdf-lib cannot write XFA back, so a
    // dynamic XFA form is view-and-print only here; see the warning below.
    enableXfa: true,
    enableScripting: false,
    isEvalSupported: false,
  });
  let pdf;
  try { pdf = await task.promise; }
  catch (e) {
    setBusy(false);
    status(`Could not open ${name}: ${e?.message || e}`, true);
    toast(`Could not open that PDF: ${e?.message || e}`, true);
    return false;
  }
  session.pdf = pdf;

  const pageInfo = [];
  for (let i = 1; i <= pdf.numPages; i++) {
    const p = await pdf.getPage(i);
    const vp = p.getViewport({ scale: 1, rotation: 0 });
    pageInfo.push({ width: vp.width, height: vp.height, rotate: p.rotate });
  }
  session.model = new DocModel({ name, pageCount: pdf.numPages, pageInfo });

  const eventBus = new lib.viewer.EventBus();
  const linkService = new lib.viewer.PDFLinkService({
    eventBus, externalLinkTarget: lib.viewer.LinkTarget.BLANK,
  });
  const layerProperties = {
    annotationEditorUIManager: null,
    annotationStorage: pdf.annotationStorage,
    downloadManager: null,
    enableScripting: false,
    fieldObjectsPromise: pdf.getFieldObjects().catch(() => null),
    findController: null,
    hasJSActionsPromise: pdf.hasJSActions().catch(() => false),
    linkService,
  };

  session.strip = new PageStrip({
    container: $("viewerContainer"), viewer: $("viewer"),
    pdfjsLib: lib, pdf, model: session.model, eventBus, layerProperties,
  });
  await session.strip.build();

  // A shim is all PDFLinkService needs to make a PDF's own table-of-contents
  // links jump to the right page.
  linkService.setViewer(linkShim(session.strip, session.model));
  linkService.setDocument(pdf, null);

  session.rail = new Rail({
    list: $("rail-list"), countEl: $("rail-count"),
    model: session.model, strip: session.strip,
    host: { rotate: onRotate, toggleDelete: onToggleDelete, reorder: onReorder },
  });
  session.rail.build();

  session.tools = new Tools({
    strip: session.strip, model: session.model,
    host: {
      toast,
      onChange: () => { paintChrome(); },
      selectTool,
      onSelectionChange: paintSelectionBar,
      editText: onTextModal,
      openSignaturePad: onSignaturePad,
      signature: () => savedSignature,
    },
  });
  session.tools.setTool("select");

  session.strip.onCurrentChange((uid) => { session.rail.markCurrent(uid); paintPageInfo(); });
  session.model.onChange(() => { paintChrome(); });

  setBusy(false);
  const forms = await countFields(pdf);
  const notes = [`${pdf.numPages} page${pdf.numPages === 1 ? "" : "s"}`];
  if (forms.fields) notes.push(`${forms.fields} form field${forms.fields === 1 ? "" : "s"}`);
  if (forms.xfa) notes.push("XFA form — fields can be filled here but cannot be saved back");
  status(notes.join(" · "), !!forms.xfa);
  paintChrome();
  paintPageInfo();
  return true;
}

async function countFields(pdf) {
  let fields = 0, xfa = false;
  try {
    const fo = await pdf.getFieldObjects();
    if (fo) for (const v of fo.values()) fields += v.length;
  } catch {}
  try { xfa = !!(await pdf.getMetadata())?.info?.IsXFAPresent; } catch {}
  return { fields, xfa };
}

function linkShim(strip, model) {
  return {
    get pagesCount() { return model.visible().length; },
    get currentPageNumber() { return Math.max(1, model.visible().indexOf(strip.current) + 1); },
    set currentPageNumber(n) { const uid = model.visible()[n - 1]; if (uid) strip.scrollTo(uid); },
    get currentScaleValue() { return strip.scaleMode; },
    set currentScaleValue(v) { strip.setScaleMode(Number.isFinite(+v) ? +v : v); },
    get currentScale() { return strip.scale; },
    get isInPresentationMode() { return false; },
    scrollPageIntoView({ pageNumber }) {
      // pageNumber is a SOURCE page number; map it through our order so a link
      // still lands on the right page after a reorder.
      const uid = model.order.find((u) => model.page(u).src === pageNumber - 1);
      if (uid && !model.page(uid).deleted) strip.scrollTo(uid);
    },
    get pageViewsReady() { return true; },
    getPageView(i) { const uid = model.visible()[i]; return uid ? strip.views.get(uid)?.pv : null; },
  };
}

async function teardown() {
  // Tools first: it is the one holding listeners on the container, and a stale
  // one would go on handling clicks against a strip that no longer exists.
  try { session.tools?.destroy(); } catch {}
  try { session.strip?.destroy(); } catch {}
  try { session.rail?.destroy(); } catch {}
  try { await session.pdf?.destroy(); } catch {}
  session.pdf = null; session.model = null; session.strip = null;
  session.rail = null; session.tools = null;
  $("viewer").textContent = "";
}

// ---- open paths -------------------------------------------------------
async function openFile(file) {
  if (!file) return;
  const looksPdf = /\.pdf$/i.test(file.name) || file.type === "application/pdf";
  if (!looksPdf) { toast(`${file.name} is not a PDF`, true); return; }
  if (!(await confirmDiscard())) return;
  const buf = new Uint8Array(await file.arrayBuffer());
  if (buf.subarray(0, 5).every((b, i) => b === "%PDF-".charCodeAt(i)) === false) {
    toast("That file does not start with a PDF header", true);
    return;
  }
  await loadBytes(buf, file.name);
}

$("file-input").addEventListener("change", (e) => {
  const f = e.target.files?.[0];
  e.target.value = "";
  openFile(f);
});
const pick = () => $("file-input").click();
$("open").addEventListener("click", pick);
$("open2").addEventListener("click", pick);

// Drag and drop anywhere in the tab.
for (const type of ["dragenter", "dragover"]) {
  window.addEventListener(type, (e) => {
    if (![...(e.dataTransfer?.types || [])].includes("Files")) return;
    e.preventDefault();
    e.dataTransfer.dropEffect = "copy";
    document.body.dataset.dragover = "1";
  });
}
window.addEventListener("dragleave", (e) => {
  if (e.relatedTarget) return;      // still inside the window
  document.body.dataset.dragover = "";
});
window.addEventListener("drop", (e) => {
  if (![...(e.dataTransfer?.types || [])].includes("Files")) return;
  e.preventDefault();
  document.body.dataset.dragover = "";
  openFile(e.dataTransfer.files?.[0]);
});

// ---- page operations --------------------------------------------------
async function onRotate(uid) {
  session.model.rotatePage(uid, 90);
  session.strip.layout();
  await session.strip.redraw(uid);
  session.rail.refresh(uid);
  paintChrome();
}
function onToggleDelete(uid) {
  const was = session.model.page(uid).deleted;
  const ok = session.model.setDeleted(uid, !was);
  if (!ok && !was) { toast("A PDF needs at least one page", true); return; }
  session.strip.layout();
  session.rail.build();
  paintChrome();
  paintPageInfo();
}
function onReorder(uid, beforeUid) {
  session.model.reorder(uid, beforeUid);
  session.strip.layout();
  session.rail.build();
  paintChrome();
  paintPageInfo();
}
$("restore-pages").addEventListener("click", () => {
  session.model.restoreAllPages();
  session.strip.layout();
  session.rail.build();
  paintChrome();
});

// ---- toolbar ----------------------------------------------------------
let redactAcknowledged = false;
let flattenRedactions = true;

/**
 * Arm a tool and sync the toolbar. Tools calls this itself after placing a
 * stamp, so the button highlight and the armed tool cannot drift apart.
 */
function selectTool(t) {
  for (const o of document.querySelectorAll(".tool")) o.classList.toggle("active", o.dataset.tool === t);
  session.tools?.setTool(t);
  status(TOOL_HINTS[t] || "");
}

for (const b of document.querySelectorAll(".tool[data-tool]")) {
  b.addEventListener("click", async () => {
    const t = b.dataset.tool;
    if (t === "redact" && !redactAcknowledged) {
      const ok = await openModal("modal-redact");
      if (!ok) return;
      redactAcknowledged = true;
      flattenRedactions = $("redact-flatten").checked;
      try { await sm?.storage?.set("redactAcknowledged", true); } catch {}
    }
    selectTool(t);
  });
}
$("redact-ok").addEventListener("click", () => closeModal(true));
$("redact-cancel").addEventListener("click", () => closeModal(null));

const TOOL_HINTS = {
  select: "Click a mark to select it. Drag to move, drag a handle to resize, double-click text to edit.",
  highlight: "Drag across text to highlight it.",
  underline: "Drag across text to underline it.",
  strikeout: "Drag across text to strike it through.",
  pen: "Drag to draw.",
  rect: "Drag to draw a rectangle.",
  ellipse: "Drag to draw an ellipse.",
  line: "Drag to draw a line.",
  arrow: "Drag from tail to head.",
  text: "Click where the text should start.",
  signature: "Click to place your signature.",
  redact: "Drag a box over what has to go. Redacted pages are rebuilt as images on save.",
};

for (const s of document.querySelectorAll(".swatch")) {
  s.addEventListener("click", () => {
    for (const o of document.querySelectorAll(".swatch")) o.classList.toggle("active", o === s);
    session.tools?.setColor(s.dataset.color);
  });
}
const fillBtn = $("toggle-fill");
if (fillBtn) fillBtn.addEventListener("click", () => {
  const on = !fillBtn.classList.contains("active");
  fillBtn.classList.toggle("active", on);
  session.tools?.setFill(on);
});

for (const w of document.querySelectorAll(".width")) {
  w.addEventListener("click", () => {
    for (const o of document.querySelectorAll(".width")) o.classList.toggle("active", o === w);
    session.tools?.setWidth(parseFloat(w.dataset.width));
  });
}

$("undo").addEventListener("click", () => { session.model?.undo(); afterHistory(); });
$("redo").addEventListener("click", () => { session.model?.redo(); afterHistory(); });
function afterHistory() {
  if (!session.model) return;
  session.strip.layout();
  session.rail.build();
  // Through select() rather than by assignment, so the selection bar hears
  // about it and does not hang over a mark that undo just removed.
  session.tools.select(null);
  paintChrome();
  paintPageInfo();
}

$("zoom").addEventListener("change", (e) => {
  const v = e.target.value;
  session.strip?.setScaleMode(/^[\d.]+$/.test(v) ? parseFloat(v) : v);
  paintPageInfo();
  positionSelectionBar();
});
$("zoom-in").addEventListener("click", () => { session.strip?.stepScale(1); syncZoomSelect(); });
$("zoom-out").addEventListener("click", () => { session.strip?.stepScale(-1); syncZoomSelect(); });
function syncZoomSelect() {
  positionSelectionBar();
  if (!session.strip) return;
  const exact = String(session.strip.scale);
  const opt = [...$("zoom").options].find((o) => o.value === exact);
  $("zoom").value = opt ? exact : $("zoom").value;
  paintPageInfo();
}
$("toggle-rail").addEventListener("click", () => {
  const off = document.body.dataset.rail === "off";
  document.body.dataset.rail = off ? "" : "off";
  if (off) session.rail?.build();
  session.strip?.computeScale();
  session.strip?.layout();
  paintPageInfo();
});

let resizeT = null;
window.addEventListener("resize", () => {
  clearTimeout(resizeT);
  resizeT = setTimeout(() => {
    if (!session.strip) return;
    if (typeof session.strip.scaleMode === "string") { session.strip.computeScale(); session.strip.layout(); }
    paintPageInfo();
    positionSelectionBar();
  }, 140);
});

// ---- selection bar ----------------------------------------------------
//
// A floating strip pinned to whatever is selected, carrying the actions that
// only make sense for that mark: edit and type controls for text, fill for a
// shape, and duplicate/delete for anything. Position is fixed rather than
// parented into the page, so it is never clipped by a page edge and never has
// to be re-homed when the selection moves to another page.
//
// It exists because Delete-on-the-keyboard was the only way to remove a mark,
// which is undiscoverable: nothing on screen said a selected mark could go.

const selbar = $("selbar");

function paintSelectionBar(id) {
  const a = id && session.model ? session.model.annot(id) : null;
  if (!a) { selbar.hidden = true; return; }
  const isText = a.kind === "text";
  const isShape = a.kind === "rect" || a.kind === "ellipse";
  $("sb-edit").hidden = !isText;
  $("sb-textsize").hidden = !isText;
  $("sb-bold").hidden = !isText;
  $("sb-italic").hidden = !isText;
  $("sb-fill").hidden = !isShape;
  if (isText) {
    $("sb-size").textContent = String(Math.round(a.size || 12));
    $("sb-bold").classList.toggle("active", !!a.bold);
    $("sb-italic").classList.toggle("active", !!a.italic);
  }
  if (isShape) $("sb-fill").classList.toggle("active", !!a.fill);
  selbar.hidden = false;
  positionSelectionBar();
}

function positionSelectionBar() {
  const t = session.tools, m = session.model, strip = session.strip;
  const a = t && m ? m.annot(t.selected) : null;
  if (!a || selbar.hidden) return;
  const ov = strip?.overlayFor(a.page);
  const view = strip?.views.get(a.page);
  if (!ov?.viewport || !view) { selbar.hidden = true; return; }
  const b = boundsOf(a);
  const [ax, ay] = ov.toView(b.x, b.y + b.h);
  const [bx, by] = ov.toView(b.x + b.w, b.y);
  const pr = view.pv.div.getBoundingClientRect();
  const left = pr.left + Math.min(ax, bx);
  const right = pr.left + Math.max(ax, bx);
  const top = pr.top + Math.min(ay, by);
  const bottom = pr.top + Math.max(ay, by);

  const box = selbar.getBoundingClientRect();
  const cr = $("viewerContainer").getBoundingClientRect();
  const GAP = 10;
  // Above the mark by preference; below when there is no room up there.
  let y = top - box.height - GAP;
  if (y < cr.top + 4) y = Math.min(bottom + GAP, cr.bottom - box.height - 4);
  let x = (left + right) / 2 - box.width / 2;
  x = Math.min(Math.max(x, cr.left + 4), cr.right - box.width - 4);
  selbar.style.left = `${Math.round(x)}px`;
  selbar.style.top = `${Math.round(y)}px`;
  // A selection scrolled out of the viewport takes its bar with it.
  selbar.classList.toggle("offscreen", bottom < cr.top || top > cr.bottom);
}

// The bar would jitter under the cursor mid-gesture, so it steps aside while
// a drag is in flight and comes back where the mark ended up.
$("viewerContainer").addEventListener("pointerdown", () => { document.body.dataset.dragging = "1"; });
window.addEventListener("pointerup", () => {
  document.body.dataset.dragging = "";
  positionSelectionBar();
});
$("viewerContainer").addEventListener("scroll", () => positionSelectionBar(), { passive: true });

$("sb-edit").addEventListener("click", () => {
  const id = session.tools?.selected;
  if (id) onTextModal(id, null);
});
$("sb-del").addEventListener("click", () => { session.tools?.deleteSelected(); paintChrome(); });
$("sb-dup").addEventListener("click", () => { session.tools?.duplicateSelected(); paintChrome(); });
$("sb-bold").addEventListener("click", () => toggleTextStyle("bold"));
$("sb-italic").addEventListener("click", () => toggleTextStyle("italic"));
$("sb-fill").addEventListener("click", () => {
  const a = session.model?.annot(session.tools?.selected);
  if (a) session.tools.setFill(!a.fill);
});
$("sb-smaller").addEventListener("click", () => stepTextSize(-1));
$("sb-bigger").addEventListener("click", () => stepTextSize(1));

function toggleTextStyle(which) {
  const a = session.model?.annot(session.tools?.selected);
  if (!a || a.kind !== "text") return;
  delete a._w;                      // the glyphs change width; re-measure
  session.tools.patchSelected({ [which]: !a[which] });
}
function stepTextSize(dir) {
  const a = session.model?.annot(session.tools?.selected);
  if (!a || a.kind !== "text") return;
  const steps = [6, 8, 9, 10, 11, 12, 14, 16, 18, 24, 30, 36, 48, 60, 72, 96];
  const at = a.size || 12;
  const next = dir > 0 ? steps.find((v) => v > at + 0.01) : [...steps].reverse().find((v) => v < at - 0.01);
  if (next == null) return;
  delete a._w;
  session.tools.patchSelected({ size: clampFont(next) });
}

// ---- text stamp -------------------------------------------------------
/**
 * One dialog for both jobs. `id` set means rewrite that mark in place, which
 * is what a double-click on placed text opens; `at` set means place a new one.
 */
async function onTextModal(id, at) {
  const existing = id ? session.model?.annot(id) : null;
  $("modal-text-title").textContent = existing ? "Edit text" : "Text stamp";
  $("text-body").value = existing ? existing.text : "";
  $("text-size").value = String(existing ? existing.size || 12 : 12);
  $("text-bold").classList.toggle("active", !!existing?.bold);
  $("text-italic").classList.toggle("active", !!existing?.italic);
  $("text-warn").hidden = true;
  const p = openModal("modal-text");
  setTimeout(() => { $("text-body").focus(); $("text-body").select(); }, 30);
  const ok = await p;
  if (!ok) return null;
  const props = {
    text: $("text-body").value,
    size: parseFloat($("text-size").value) || 12,
    bold: $("text-bold").classList.contains("active"),
    italic: $("text-italic").classList.contains("active"),
  };
  return existing ? session.tools.updateText(id, props) : session.tools.placeText(at, props);
}
for (const b of [$("text-bold"), $("text-italic")]) {
  b?.addEventListener("click", () => b.classList.toggle("active"));
}
$("text-ok").addEventListener("click", () => closeModal(true));
$("text-cancel").addEventListener("click", () => closeModal(null));
$("text-body").addEventListener("input", () => {
  const n = unencodableStampsIn($("text-body").value);
  const w = $("text-warn");
  w.hidden = n === 0;
  w.classList.add("warn");
  if (n) w.textContent = `${n} character${n === 1 ? "" : "s"} cannot be written with the built-in font and will be saved as "?".`;
});
function unencodableStampsIn(text) {
  // Same WinAnsi test the writer uses, applied live so the user finds out
  // before placing the stamp rather than after saving.
  let n = 0;
  for (const ch of String(text)) {
    const code = ch.codePointAt(0);
    const ok = (code >= 0x20 && code <= 0x7e) || (code >= 0xa0 && code <= 0xff) ||
      [0x2018, 0x2019, 0x201c, 0x201d, 0x2013, 0x2014, 0x2022, 0x20ac, 0x2026, 0x2122].includes(code) ||
      ch === "\n";
    if (!ok) n++;
  }
  return n;
}

// ---- signature --------------------------------------------------------
let savedSignature = null;
let pad = null;
async function onSignaturePad() {
  if (!pad) {
    pad = new SignaturePad($("sign-pad"));
    pad.onChange((has) => { $("sign-ok").disabled = !has; });
  }
  pad.clear();
  const ok = await openModal("modal-sign");
  if (!ok) return null;
  const res = pad.result();
  if (!res) return null;
  savedSignature = res;
  try { await sm?.storage?.set("signature", res); } catch {}
  return res;
}
$("sign-ok").addEventListener("click", () => closeModal(true));
$("sign-cancel").addEventListener("click", () => closeModal(null));
$("sign-clear").addEventListener("click", () => pad?.clear());

// ---- save -------------------------------------------------------------
function defaultSaveName() {
  const base = String(session.name || "document.pdf").replace(/\.pdf$/i, "");
  return `${base}-edited.pdf`;
}

/**
 * Everything the user typed into a form field, keyed by field NAME.
 *
 * Driven from the document's field list rather than from the storage's
 * contents. pdf.js keys its annotation storage by annotation id ("11R"), which
 * means nothing to pdf-lib — pdf-lib addresses fields by name — so the field
 * list is needed for the mapping either way, and iterating it also keeps
 * pdf.js's own editor bookkeeping out of the results for free.
 */
async function harvestFormValues(pdf) {
  const out = [];
  let fields = null;
  try { fields = await pdf.getFieldObjects(); } catch { return out; }
  if (!fields) return out;
  const storage = pdf.annotationStorage;
  for (const [name, objs] of fields) {
    for (const o of objs || []) {
      // `has` distinguishes a field the user touched from one they left alone;
      // writing back every field would rewrite appearances across the whole
      // document for no reason.
      if (!o?.id || !storage.has(o.id)) continue;
      const entry = storage.getRawValue(o.id);
      if (!entry || typeof entry !== "object" || !("value" in entry)) continue;
      out.push({ name, value: entry.value });
      break;   // a field's kids (radio buttons) share one value
    }
  }
  return out;
}

/** Render one page to a PNG at FLATTEN_DPI, unrotated, for the flatten pass. */
async function rasterizePage(uid) {
  const entry = session.strip.views.get(uid);
  const scale = FLATTEN_DPI / 72;
  // rotation 0, so the image lands in the page's own unrotated coordinate
  // space — the page's /Rotate then presents it exactly as before.
  const vp = entry.pdfPage.getViewport({ scale, rotation: 0 });
  const canvas = document.createElement("canvas");
  canvas.width = Math.max(1, Math.ceil(vp.width));
  canvas.height = Math.max(1, Math.ceil(vp.height));
  const ctx = canvas.getContext("2d", { alpha: false });
  ctx.fillStyle = "#ffffff";
  ctx.fillRect(0, 0, canvas.width, canvas.height);
  await entry.pdfPage.render({ canvasContext: ctx, viewport: vp, intent: "print" }).promise;
  const blob = await new Promise((res, rej) =>
    canvas.toBlob((b) => b ? res(b) : rej(new Error("toBlob returned null")), "image/png"));
  return new Uint8Array(await blob.arrayBuffer());
}

async function doSave() {
  const m = session.model;
  if (!m) return;
  $("save-name").value = defaultSaveName();
  const summary = $("save-summary");
  summary.textContent = "";
  const lines = [];
  if (m.annots.length) lines.push([`${m.annots.length} mark${m.annots.length === 1 ? "" : "s"} written into the file`, false]);
  const formValues = await harvestFormValues(session.pdf);
  if (formValues.length) lines.push([`${formValues.length} form field${formValues.length === 1 ? "" : "s"} filled in`, false]);
  if (m.deletedCount()) lines.push([`${m.deletedCount()} page${m.deletedCount() === 1 ? "" : "s"} removed`, false]);
  if (m.pagesChanged() && !m.deletedCount()) lines.push(["pages reordered", false]);
  if (m.rotationsChanged()) lines.push(["page rotation changed", false]);
  const red = m.redactedPages();
  if (red.size) {
    lines.push([flattenRedactions
      ? `${red.size} redacted page${red.size === 1 ? "" : "s"} rebuilt as an image, so the text under the boxes is gone`
      : `${red.size} redacted page${red.size === 1 ? "" : "s"} — the text under the boxes stays extractable`,
      !flattenRedactions]);
  }
  const bad = unencodableStamps(m);
  if (bad) lines.push([`${bad} text stamp${bad === 1 ? "" : "s"} contain characters the built-in font cannot write`, true]);
  if (!lines.length) lines.push(["no changes — this saves a copy of the original", false]);
  for (const [text, warn] of lines) {
    const li = document.createElement("li");
    li.textContent = text;
    if (warn) li.className = "warn";
    summary.append(li);
  }

  const go = await openModal("modal-save");
  if (!go) return;
  let filename = String($("save-name").value || "").trim() || defaultSaveName();
  if (!/\.pdf$/i.test(filename)) filename += ".pdf";

  setBusy(true, "Writing…");
  try {
    const { bytes, report } = await buildPdf({
      originalBytes: session.bytes,
      model: m,
      formValues,
      flatten: flattenRedactions,
      rasterize: rasterizePage,
    });
    const blob = new Blob([bytes], { type: "application/pdf" });
    const url = URL.createObjectURL(blob);
    const a = $("download-link");
    a.href = url;
    a.download = filename;
    a.click();
    setTimeout(() => URL.revokeObjectURL(url), 8000);
    m.markSaved();
    paintChrome();
    const kb = (bytes.length / 1024).toFixed(0);
    status(`Saved ${filename} · ${kb} KB${report.flattened ? ` · ${report.flattened} page(s) rebuilt as images` : ""}`);
    toast(`Saved ${filename} (${kb} KB)`);
    for (const w of report.warn) toast(w, true);
  } catch (e) {
    console.error("save failed:", e);
    status(`Save failed: ${e?.message || e}`, true);
    toast(`Save failed: ${e?.message || e}`, true);
  } finally {
    setBusy(false);
  }
}
$("save").addEventListener("click", doSave);
$("save-go").addEventListener("click", () => closeModal(true));
$("save-cancel").addEventListener("click", () => closeModal(null));

// ---- discard / close --------------------------------------------------
async function confirmDiscard() {
  if (!session.model || !session.model.isDirty()) return true;
  // Deliberately the browser's own confirm(): it is modal against the tab, it
  // cannot be dismissed by a stray click the way the in-page scrim can, and
  // losing an hour of markup to a misplaced click is not a risk worth a
  // prettier dialog.
  return window.confirm("This document has unsaved changes. Discard them?");
}
$("discard").addEventListener("click", async () => {
  if (!(await confirmDiscard())) return;
  if (session.scratchId && sm?.invoke) {
    try { await sm.invoke("release", { id: session.scratchId }); } catch {}
  }
  try { sm?.closeTab?.(); } catch {}
});
// Belt and braces for a tab closed from the tab strip rather than our button.
window.addEventListener("beforeunload", (e) => {
  if (session.model?.isDirty()) { e.preventDefault(); e.returnValue = ""; }
});

// A link inside a PDF must not navigate this tab — that would drop the whole
// editing session on the floor. Hand it to the add-on, which opens a new tab.
$("viewerContainer").addEventListener("click", (e) => {
  const a = e.target?.closest?.("a[href]");
  if (!a) return;
  const href = a.getAttribute("href") || "";
  if (!/^https?:/i.test(href)) return;
  e.preventDefault();
  e.stopPropagation();
  sm?.invoke?.("openExternal", { url: href })
    .catch((err) => toast(`Could not open that link: ${err?.message || err}`, true));
}, true);

// ---- keyboard ---------------------------------------------------------
// Ctrl+F, Ctrl+B and Ctrl +/-/0 never reach this page — Theseus claims them
// app-wide for find, the add-on sidebar and tab zoom. PDF zoom therefore lives
// on bare +/-/0, which is what desktop readers use anyway.
const TOOL_KEYS = {
  v: "select", h: "highlight", u: "underline", k: "strikeout", p: "pen",
  r: "rect", o: "ellipse", l: "line", a: "arrow", t: "text", g: "signature",
};
window.addEventListener("keydown", (e) => {
  // A modal owns the keyboard while it is up: Escape cancels, and Enter
  // commits unless the focus is in the textarea, where it means a newline.
  if (!$("scrim").hidden) {
    if (e.key === "Escape") { closeModal(null); e.preventDefault(); return; }
    if (e.key === "Enter" && e.target?.tagName !== "TEXTAREA" && !e.shiftKey) {
      const go = document.querySelector(".modal:not([hidden]) .btn.primary:not(:disabled)");
      if (go) { go.click(); e.preventDefault(); }
    }
    return;
  }
  const typing = /^(INPUT|TEXTAREA|SELECT)$/.test(e.target?.tagName || "") || e.target?.isContentEditable;
  const meta = e.ctrlKey || e.metaKey;

  if (meta && e.key.toLowerCase() === "s") { e.preventDefault(); doSave(); return; }
  if (meta && e.key.toLowerCase() === "o") { e.preventDefault(); pick(); return; }
  if (meta && e.key.toLowerCase() === "d") {
    e.preventDefault();
    if (session.tools?.duplicateSelected()) paintChrome();
    return;
  }
  if (meta && e.key.toLowerCase() === "z") {
    e.preventDefault();
    if (e.shiftKey) session.model?.redo(); else session.model?.undo();
    afterHistory();
    return;
  }
  if (typing) return;

  if (e.key === "Escape") {
    // Step back one level at a time: drop the selection first, and only then
    // disarm the tool. Doing both at once loses whichever the user meant.
    if (session.tools?.selected) { session.tools.select(null); e.preventDefault(); return; }
    if (session.tools?.tool !== "select") { selectTool("select"); e.preventDefault(); }
    return;
  }
  if (e.key === "Delete" || e.key === "Backspace") {
    if (session.tools?.deleteSelected()) { paintChrome(); e.preventDefault(); }
    return;
  }
  if (e.key === "Enter") {
    const sel = session.tools?.selected;
    const a = sel && session.model?.annot(sel);
    if (a?.kind === "text") { onTextModal(sel, null); e.preventDefault(); }
    return;
  }
  if (e.key === "+" || e.key === "=") { session.strip?.stepScale(1); syncZoomSelect(); e.preventDefault(); return; }
  if (e.key === "-") { session.strip?.stepScale(-1); syncZoomSelect(); e.preventDefault(); return; }
  if (e.key === "0") { $("zoom").value = "page-width"; session.strip?.setScaleMode("page-width"); paintPageInfo(); e.preventDefault(); return; }

  const t = TOOL_KEYS[e.key.toLowerCase()];
  if (t) { document.querySelector(`.tool[data-tool="${t}"]`)?.click(); e.preventDefault(); }
});

// ---- start ------------------------------------------------------------
(async function start() {
  try {
    redactAcknowledged = (await sm?.storage?.get("redactAcknowledged", false)) === true;
    const sig = await sm?.storage?.get("signature", null);
    if (sig && Array.isArray(sig.strokes)) savedSignature = sig;
  } catch {}

  const id = new URLSearchParams(location.search).get("doc");
  if (!id) { status("Drop a PDF here, or use Open."); paintChrome(); return; }
  if (!sm?.invoke) { status("This page has to be opened from the PDF Editor add-on.", true); return; }
  setBusy(true, "Fetching…");
  try {
    const res = await sm.invoke("getBytes", { id });
    const bytes = res.data instanceof Uint8Array ? res.data : new Uint8Array(res.data);
    await loadBytes(bytes, res.name || "document.pdf", id);
  } catch (e) {
    setBusy(false);
    status(`Could not load that document: ${e?.message || e}`, true);
    paintChrome();
  }
})();