Every kind of balloon on a lighthouse page

// ═══ Postext Cookbook · Nº 145 · Every kind of balloon on a lighthouse page ═════════
// https://postext.dev/en/cookbook/balloon-kinds
// Code: MIT · Text: original (CC BY 4.0) · Pictures: generated with diffusion models
// Fonts: Comic Neue, Bangers and the faces of five editions (OFL) · Needs postext ≥ 1.21.0
//
// One comic page that uses every kind of balloon the engine draws, with a letterer's style
// sheet in front of it. Each line of the script names its speaker and, when it is not plain
// speech, its kind; the shape, the tail and the type follow from the balloon style.
import {
  buildDocument, renderPageToCanvas, clearMeasurementCache, registerResourceImage,
  loadVerticalAlternates,
} from 'https://esm.sh/postext';
import { renderToPdf, decompressWoff2 } from 'https://esm.sh/postext-pdf';

const LANG = 'en'; // @lang: the sample's language: 'en' | 'es' | 'ca' | 'zh' | 'ar' | 'ja' | 'pt'
const RECIPE = 'balloon-kinds';

// ─── 1 · Design ─────────────────────────────────────────────────────────────
// #region palette: a storm at night, and the yellow of the captions
const palette = {
  ink: '#18202b', // panel borders, lettering and text: a blue-black
  accent: '#c2412d', // sound effects and the style sheet's labels
  caption: '#f3e3a8', // narration boxes
  inner: '#e4e8ee', // the inner voice: a cold grey-blue
  muted: '#5c6672', // folios and the imprint
  paper: '#fdfbf6',
};
const col = (id) => ({ hex: palette[id], model: 'hex', paletteId: id });
const colorPalette = [
  ...Object.entries(palette).map(([id, hex]) => ({ id, name: id, value: { hex, model: 'hex' } })),
  { id: 'main-color', name: 'accent (defaults)', value: { hex: palette.accent, model: 'hex' } },
];
// #endregion

// #region editions: six editions, each lettered in faces for its script
// The engine's default lettering and sound-effect faces, but for Chinese two ZCOOL faces drawn
// for cartoons. content.<lang>.md holds the words under the same speaker ids.
const [LETTERING, SFX] = t({
  en: ['Comic Neue', 'Bangers'], es: ['Comic Neue', 'Bangers'], ca: ['Comic Neue', 'Bangers'],
  ja: ['Zen Antique', 'Dela Gothic One'], zh: ['ZCOOL KuaiLe', 'ZCOOL QingKe HuangYou'],
  ar: ['Playpen Sans Arabic', 'Lalezar'], pt: ['Comic Neue', 'Bangers'],
});
// #endregion

// #region answer: one balloon style per kind, and a cast that gives the skipper his radio
// A script line is `speaker{kind}: text`. The kinds are balloon styles: the engine ships
// speech, thought, whisper, shout, radio, caption, inner, note and sfx, and a style of the
// same id here changes only what it names. `caption`, `note` and `sfx` are reserved speakers.
const balloonStyles = [
  { id: 'speech', stroke: col('ink') }, // an oval, a curved tail to the mouth
  { id: 'thought', stroke: col('ink') }, // a cloud, bubbles to the head
  { id: 'whisper', stroke: col('ink') }, // a dashed outline, 0.9 × the type
  { id: 'shout', stroke: col('ink'), burstPoints: 16 }, // a burst, bold, 1.15 × the type
  { id: 'radio', stroke: col('ink') }, // a zig-zag outline and tail: a voice through a set
  { id: 'caption', fill: col('caption'), stroke: col('ink') }, // narration, butted to a corner
  { id: 'inner', fill: col('inner'), stroke: col('ink') }, // no tail, italic where it can be
  { id: 'note', fill: col('paper'), stroke: col('ink') }, // the editor's note, 0.8 × the type
  { id: 'sfx', fontFamily: SFX, color: col('accent'), haloColor: col('paper') }, // no balloon
];
const comics = {
  gutter: { horizontal: mm(4), vertical: mm(3) },
  panel: { borderWidth: pt(1), borderColor: col('ink'), background: col('paper') },
  lettering: { fontFamily: LETTERING, fontSize: pt(7.5), color: col('ink'), inset: mm(1) },
  balloonStyles,
  // A speaker's own style: every `skipper:` line comes through the radio unless it says not.
  cast: [{ id: 'skipper', balloonStyle: 'radio', name: t({ en: 'The skipper', es: 'El patrón',
    ca: 'El patró', zh: '船长', ar: 'الربّان', ja: '船長', pt: 'O capitão' }) }],
  runningHeads: true, // a comic page has no running head unless asked: here, its folio
};
// #endregion

const LABEL = { fontFamily: LETTERING, fontSize: pt(7.5), color: col('muted') };
const footer = { elements: [{ kind: 'text', id: 'folio', content: '{pageNumber}', ...LABEL,
  align: 'center', placement: { anchor: { to: 'page', edge: 'bottom' },
    offset: { x: mm(0), y: mm(-8) } } }] };

const config = () => ({ // a factory: the engine caches resolved configs per object
  locale: t({ en: 'en-us', es: 'es', ca: 'ca', ja: 'ja', zh: 'zh-Hans', ar: 'ar',
    pt: 'pt-BR' }),
  colorPalette, comics,
  // The trim of an American comic book, 6⅝ × 10³⁄₁₆ in; the type area is the panel frame.
  page: { sizePreset: 'custom', width: mm(168), height: mm(259), dpi: 150,
    backgroundColor: col('paper'),
    margins: { top: mm(14), bottom: mm(18), left: mm(13), right: mm(11), mirror: true } },
  layout: { layoutType: 'single' },
  // The style sheet is set in the lettering face of the edition.
  bodyText: { fontFamily: LETTERING, fontSize: pt(9.5), lineHeight: pt(13.5), color: col('ink'),
    boldColor: col('ink'), italicColor: col('ink'), referenceColor: col('ink'),
    textAlign: 'left', firstLineIndent: pt(0), paragraphSpacing: true,
    hyphenation: { enabled: false } },
  headings: { fontFamily: SFX, color: col('accent'), fontWeight: 400,
    levels: [
      // Restated: any headings object drops the H1 break (gotcha: headings-drop-h1-break).
      { level: 1, fontSize: pt(34), lineHeight: pt(38), breakBefore: { enabled: true,
        parity: 'any' }, marginTop: mm(18), marginBottom: pt(13.5) },
      { level: 2, fontFamily: LETTERING, fontSize: pt(9.5), fontWeight: 700,
        color: col('accent'), marginTop: pt(13.5), marginBottom: pt(0) },
    ] },
  unorderedLists: { bulletChar: '–', color: col('accent'), fontWeight: 400,
    marginTop: pt(0), marginBottom: pt(0) },
  // The script's markup on the style sheet: a chip in the caption yellow.
  chipStyles: [{ id: 'code', background: col('caption'), color: col('ink'), borderWidth: pt(0),
    borderRadius: pt(1.5), fontFamily: LETTERING, fontSize: em(0.9), paddingX: em(0.3),
    paddingY: em(0.1) }],
  paragraphStyles: [{ id: 'imprint', fontSize: pt(7.5), lineHeight: pt(10), color: col('muted'),
    marginTop: pt(27) }],
  header: { elements: [] }, footer,
});

// ─── 2 · Content ────────────────────────────────────────────────────────────
const markdown = String.raw`# Lettering style sheet
Markdown sample · 47 lines · content.en.md

## The Porthcove Light · issue 3 · page 7

One line of the script is one balloon: the speaker, the kind in braces when it is not plain speech, a colon, the words. The shapes below are the ones on page 2.

- **Speech.** :chip[tomas: Make it two.]{style="code"} An oval; the tail stops short of the speaker’s mouth.
- **Joined.** Two :chip[tomas:]{style="code"} lines in a row butt into one outline, with one tail.
- **Thought.** :chip[biscuit{thought}:]{style="code"} A cloud, with bubbles that rise towards the head.
- **Whisper.** :chip[maya{whisper}:]{style="code"} A dashed outline and smaller letters.
- **Shout.** :chip[tomas{shout}:]{style="code"} A burst, in bold, a size up.
- **Radio.** The skipper speaks through the set: the cast gives every :chip[skipper:]{style="code"} line a jagged outline and a zigzag tail.
- **Caption.** :chip[caption:]{style="code"} Narration in a yellow box, butted into a corner.
- **Inner voice.** :chip[maya{inner}:]{style="code"} What she does not say aloud: no tail, a grey box, italics.
- **Editor’s note.** :chip[note:]{style="code"} Small, in the panel’s lower corner.
- **Sound effect.** :chip[sfx{at="16% 28%" rotate=-10}:]{style="code"} No balloon: display letters in red with a white outline, placed and turned by hand.
- **Off-panel.** :chip[tomas{tail=end}:]{style="code"} The speaker is outside the picture; the tail runs to the panel’s edge.
- **Pinned.** :chip[skipper{at="44% 22%"}:]{style="code"} The balloon is centred on that point of the picture, whatever the crop.

:::paragraphs{style="imprint"}
Story and lettering for the Postext Cookbook. Pictures generated with diffusion models. Lettered in Comic Neue and Bangers (SIL OFL).
:::

:::page{split="32 [58 | *] / 34 [42 | *] / * [40 | *]"}
::panel{art=bk-storm}
caption: Ten o’clock. The storm had found the headland.
skipper: Porthcove light, this is the *Gannet*. Engine’s dead. We’re drifting.
tomas: *Gannet*, I hear you. Hold on.
note{at=bottom-end}: The *Gannet* had fished out of Porthcove for forty years. —Ed.
::panel{art=bk-whisper}
maya{whisper}: It’s all right, Biscuit. Grandpa’s done this before.
biscuit{thought}: Has he, though?
::panel{art=bk-shout}
tomas{shout}: *Gannet!* Steer for the light! Keep it on your bow!
::panel{art=bk-sea}
sfx{at="16% 28%" rotate=-10}: KRA-KOOM
skipper{at="44% 22%"}: We see it… we see the light…
tomas{tail=end}: Easy now. Bring her round slow.
::panel{art=bk-window}
maya{inner}: Come on. Come on. Come on.
caption{at=bottom-start}: It took them two hours.
::panel{art=bk-morning}
caption{at=top-start}: Morning.
skipper{speech tail=bottom}: Thank you, keeper! I owe you a crate of mackerel!
tomas: Make it two.
tomas: One’s for the cat.
maya: Biscuit says three.
:::
`; // content.<lang>.md, inlined by the Cookbook

// #region art: the six pictures: safe area, speakers' anchors and avoid zones
// From the art manifest; fractions of each picture, the same in every language. `skipper` in
// the storm picture is the radio set, the voice's source; in the sea picture, his boat.
const ART = {
  'bk-storm': { width: 1100, height: 733, safeArea: { x: 0.05, y: 0.26, width: 0.52, height: 0.36 },
    anchors: [{ id: 'tomas', x: 0.3, y: 0.44, head: { x: 0.32, y: 0.33 },
      face: { x: 0.26, y: 0.29, width: 0.13, height: 0.21 } },
    { id: 'maya', x: 0.475, y: 0.47, head: { x: 0.48, y: 0.38 },
      face: { x: 0.43, y: 0.35, width: 0.09, height: 0.16 } },
    { id: 'skipper', x: 0.08, y: 0.52 }],
    avoid: [{ x: 0, y: 0.38, width: 0.18, height: 0.28 }],
    alt: t({ en: 'Storm at night in the lamp room: the keeper speaks into the radio microphone '
      + 'while Maya, wrapped in a blanket, listens.',
      es: 'Noche de tormenta en la sala de la linterna: el farero habla por el micrófono de la '
        + 'radio y Maya, envuelta en una manta, escucha.',
      ca: 'Nit de tempesta a la sala de la llanterna: el faroner parla pel micròfon de la ràdio i '
        + 'la Maya, embolicada amb una manta, escolta.',
      zh: '暴风雨之夜的灯室里，守塔人对着收音机的话筒说话，裹着毯子的玛雅在一旁听着。',
      ar: 'ليلة عاصفة في غرفة الفانوس: الحارس يتكلم في ميكروفون المذياع، ومايا الملتفّة ببطانية '
        + 'تصغي.',
      ja: '嵐の夜の灯室。灯台守が無線のマイクに話しかけ、毛布にくるまったマヤが耳をすます。',
      pt: 'Noite de tempestade na sala da lanterna: o faroleiro fala ao microfone do rádio e '
        + 'Maya, enrolada num cobertor, escuta.' }) },
  'bk-whisper': { width: 1152, height: 1152,
    safeArea: { x: 0.36, y: 0.26, width: 0.44, height: 0.48 },
    anchors: [{ id: 'maya', x: 0.53, y: 0.47, head: { x: 0.52, y: 0.33 },
      face: { x: 0.41, y: 0.3, width: 0.19, height: 0.22 } },
    { id: 'biscuit', x: 0.625, y: 0.635, head: { x: 0.66, y: 0.57 },
      face: { x: 0.55, y: 0.5, width: 0.25, height: 0.22 } }],
    avoid: [],
    alt: t({ en: 'Under the desk, Maya whispers behind her hand to the frightened orange cat.',
      es: 'Bajo la mesa, Maya le susurra tapándose la boca al gato naranja asustado.',
      ca: 'Sota la taula, la Maya xiuxiueja tapant-se la boca al gat taronja espantat.',
      zh: '桌子底下，玛雅用手挡着嘴，对受惊的橘猫说悄悄话。',
      ar: 'تحت المكتب تهمس مايا من وراء يدها للقط البرتقالي الخائف.',
      ja: '机の下で、マヤが手で口をかくして、おびえたオレンジ色の猫にささやく。',
      pt: 'Debaixo da mesa, Maya cobre a boca com a mão e sussurra para o gato laranja '
        + 'assustado.' }) },
  'bk-shout': { width: 880, height: 1100, safeArea: { x: 0.22, y: 0.26, width: 0.46, height: 0.42 },
    anchors: [{ id: 'tomas', x: 0.48, y: 0.47, head: { x: 0.42, y: 0.33 },
      face: { x: 0.25, y: 0.28, width: 0.37, height: 0.32 } }],
    avoid: [{ x: 0.53, y: 0.43, width: 0.17, height: 0.27 }],
    alt: t({ en: 'Close-up of the keeper shouting into the microphone, lit from below by the '
      + 'radio dials.',
      es: 'Primer plano del farero gritando al micrófono, iluminado desde abajo por los diales de '
        + 'la radio.',
      ca: 'Primer pla del faroner cridant al micròfon, il·luminat des de baix pels dials de la '
        + 'ràdio.',
      zh: '守塔人对着话筒大喊的特写，收音机的刻度盘从下方照亮他的脸。',
      ar: 'لقطة قريبة للحارس يصرخ في الميكروفون، وأضواء لوحة المذياع تنيره من أسفل.',
      ja: 'マイクに向かって叫ぶ灯台守のアップ。無線機の目盛りの光が下から顔を照らす。',
      pt: 'Close do faroleiro gritando ao microfone, iluminado de baixo pelos mostradores do '
        + 'rádio.' }) },
  'bk-sea': { width: 1200, height: 800, safeArea: { x: 0.1, y: 0.19, width: 0.37, height: 0.57 },
    anchors: [{ id: 'skipper', x: 0.28, y: 0.63 }, { id: 'sfx', x: 0.16, y: 0.36 }],
    avoid: [{ x: 0.13, y: 0.52, width: 0.24, height: 0.23 },
      { x: 0.85, y: 0.19, width: 0.08, height: 0.26 }],
    alt: t({ en: 'A small blue trawler heaves on storm waves at night; lightning on the left, the '
      + 'lighthouse beam on the right.',
      es: 'Un pesquero azul cabecea entre las olas de la tormenta; un rayo a la izquierda, el haz '
        + 'del faro a la derecha.',
      ca: 'Un pesquer blau capcineja entre les onades de la tempesta; un llamp a l’esquerra, el '
        + 'feix del far a la dreta.',
      zh: '夜里，一艘蓝色小渔船在暴风雨的浪头上颠簸；左边是闪电，右边是灯塔的光束。',
      ar: 'قارب صيد أزرق صغير يتقاذفه موج العاصفة ليلًا؛ برق على اليسار وشعاع المنارة على اليمين.',
      ja: '夜の嵐の波にもまれる青い小さな漁船。左に稲妻、右に灯台の光。',
      pt: 'Um pequeno barco pesqueiro azul jogado pelas ondas da tempestade à noite; um raio à '
        + 'esquerda, o facho do farol à direita.' }) },
  'bk-window': { width: 1000, height: 1000,
    safeArea: { x: 0.36, y: 0.27, width: 0.28, height: 0.33 },
    anchors: [{ id: 'maya', x: 0.49, y: 0.41, head: { x: 0.42, y: 0.3 },
      face: { x: 0.41, y: 0.33, width: 0.1, height: 0.13 } }],
    avoid: [{ x: 0.5, y: 0.33, width: 0.1, height: 0.17 },
      { x: 0.83, y: 0.45, width: 0.06, height: 0.08 }],
    alt: t({ en: 'Maya presses her hands and nose to the rainy window, staring out at the storm.',
      es: 'Maya pega las manos y la nariz al cristal mojado y mira la tormenta.',
      ca: 'La Maya enganxa les mans i el nas al vidre mullat i mira la tempesta.',
      zh: '玛雅把双手和鼻子贴在满是雨水的窗户上，望着外面的暴风雨。',
      ar: 'تلصق مايا يديها وأنفها بالزجاج المبلل وتحدّق في العاصفة.',
      ja: 'マヤが雨の窓に両手と鼻を押しつけ、嵐を見つめる。',
      pt: 'Maya cola as mãos e o nariz no vidro molhado e olha a tempestade.' }) },
  'bk-morning': { width: 1000, height: 667,
    safeArea: { x: 0.33, y: 0.06, width: 0.42, height: 0.59 },
    anchors: [{ id: 'tomas', x: 0.565, y: 0.25, head: { x: 0.56, y: 0.15 },
      face: { x: 0.51, y: 0.13, width: 0.1, height: 0.17 } },
    { id: 'maya', x: 0.465, y: 0.29, head: { x: 0.45, y: 0.24 },
      face: { x: 0.41, y: 0.19, width: 0.09, height: 0.14 } },
    { id: 'biscuit', x: 0.685, y: 0.58, head: { x: 0.69, y: 0.55 },
      face: { x: 0.64, y: 0.51, width: 0.09, height: 0.11 } }],
    avoid: [{ x: 0.66, y: 0.08, width: 0.08, height: 0.12 },
      { x: 0.34, y: 0.14, width: 0.06, height: 0.08 }],
    alt: t({ en: 'Next morning on the sunny rocks, Maya, the keeper and the cat wave; the '
      + 'lighthouse stands behind them.',
      es: 'A la mañana siguiente, en las rocas al sol, Maya, el farero y el gato saludan; detrás '
        + 'está el faro.',
      ca: 'L’endemà al matí, a les roques al sol, la Maya, el faroner i el gat saluden; darrere '
        + 'hi ha el far.',
      zh: '第二天早上，阳光照着礁石，玛雅、守塔人和猫在挥手；灯塔立在他们身后。',
      ar: 'في الصباح التالي على الصخور المشمسة يلوّح مايا والحارس والقط، والمنارة خلفهم.',
      ja: '翌朝、日の当たる岩の上でマヤと灯台守と猫が手を振る。後ろに灯台が立つ。',
      pt: 'Na manhã seguinte, nas pedras ao sol, Maya, o faroleiro e o gato acenam; atrás deles '
        + 'está o farol.' }) },
};
// #endregion

// ─── 3 · Fonts ──────────────────────────────────────────────────────────────
// Every face of the six editions; each edition loads the latin files of all of them and the
// Japanese, Chinese or Arabic files of its own two (gotcha: fonts-first).
const FONTS = {
  'Comic Neue': ['400', '400i', '700', '700i'],
  Bangers: ['400'],
  'Zen Antique': ['400'],
  'Dela Gothic One': ['400'],
  'ZCOOL KuaiLe': ['400'],
  'ZCOOL QingKe HuangYou': ['400'],
  'Playpen Sans Arabic': ['400', '700'],
  Lalezar: ['400'],
};

// ─── 4 · Build & show ───────────────────────────────────────────────────────
const faces = { [LETTERING]: FONTS[LETTERING], [SFX]: FONTS[SFX] };
await loadFonts(FONTS, markdown);
await loadCjkFonts(faces, markdown, { vertical: LANG === 'ja' }); // ja balloons are vertical
await loadArabicFonts(faces, markdown);
await loadComicFonts(faces, markdown); // the bold and italic the faces do not ship
const resources = await Promise.all([
  comicPanel('bk-storm', asset('bk-storm.jpg'), ART['bk-storm']),
  comicPanel('bk-whisper', asset('bk-whisper.jpg'), ART['bk-whisper']),
  comicPanel('bk-shout', asset('bk-shout.jpg'), ART['bk-shout']),
  comicPanel('bk-sea', asset('bk-sea.jpg'), ART['bk-sea']),
  comicPanel('bk-window', asset('bk-window.jpg'), ART['bk-window']),
  comicPanel('bk-morning', asset('bk-morning.jpg'), ART['bk-morning']),
]);
const doc = await buildWithFonts(() => buildDocument({ markdown, resources }, config()), markdown);
showBook(doc, { title: t({ en: 'Every kind of balloon on a lighthouse page',
  es: 'Todos los bocadillos en una página del faro',
  pt: 'Todos os tipos de balão numa página do farol' }) });
offerPdf(() => renderToPdf(doc, { fontProvider: comicPdfProvider, resourceBytes: imageBytes }),
  `${RECIPE}.pdf`);

Kit · core, fonts, viewer, pdf, images, cjk, arabic, comics: the same in every recipe · 722 lines
// ─── Kit ── helpers shared by every Cookbook recipe · postext.dev/cookbook ─────

// ─── Kit · core v1 ── the same in every recipe · postext.dev/cookbook
function mm(value) { return { value, unit: 'mm' }; }
function pt(value) { return { value, unit: 'pt' }; }
function em(value) { return { value, unit: 'em' }; }
/** The sample language's string: t({ en: 'Figure', es: 'Figura' }). */
function t(strings) { return strings[LANG] ?? Object.values(strings)[0]; }
/** A file in this recipe's assets folder, served from the Postext repo by jsDelivr. */
function asset(file) { return `https://cdn.jsdelivr.net/gh/drnachio/postext@main/cookbook/${RECIPE}/assets/${file}`; }

// ─── Kit · fonts v2 ── the same in every recipe · postext.dev/cookbook
// Postext measures with the loaded faces and caches the widths: load every face
// before the first build, from Fontsource, the files the PDF embeds too.

/** faces = { 'Family Name': ['400', '400i', '700'] }. `text` is the sample:
 *  č ł † α χ also load latin-ext and greek files (kitSubsetsFor). With
 *  `optional`, a face Fontsource does not ship is skipped instead of failing.
 *  Resolves to the number of faces added. */
async function loadFonts(faces, text = '', { optional = false } = {}) {
  kitStatus('Loading fonts…');
  const ranges = {
    latin: 'U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,'
      + 'U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD',
    'latin-ext': 'U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,'
      + 'U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF',
    greek: 'U+0370-03FF',
  };
  const jobs = [];
  let added = 0;
  for (const [family, specs] of Object.entries(faces)) {
    const id = fontsourceId(family);
    const todo = [...new Set(specs)].map((spec) => [parseInt(spec, 10), spec.endsWith('i') ? 'italic' : 'normal'])
      .filter(([weight, style]) => !hasFace(family, weight, style)); // before any await
    const meta = optional || /[^\0-ÿ]/u.test(text) ? await fontsourceMeta(family) : null;
    const subsets = ['latin', ...kitSubsetsFor(text, meta)];
    for (const [weight, style] of todo) {
      if (optional && !(meta?.weights.includes(weight) && meta.styles.includes(style))) continue;
      for (const subset of subsets) {
        const url = `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-${subset}-${weight}-${style}.woff2`;
        const face = new FontFace(family, `url(${url}) format('woff2')`,
          { weight: String(weight), style, unicodeRange: ranges[subset] });
        jobs.push(face.load().then((ready) => { document.fonts.add(ready); added++; }, () => {
          if (subset === 'latin' && !optional) throw new Error(`Fontsource has no ${family} ${weight} ${style}`);
        }));
      }
    }
  }
  await Promise.all(jobs).catch((error) => { kitFail(error); throw error; });
  return added;
}

/** Runs `build` and loads any face the pages use that FONTS missed (a regular
 *  one with a warning), then clears the measurement cache and builds again. */
async function buildWithFonts(build, text = '') {
  const tried = new Set();
  for (let round = 0; round < 3; round++) {
    kitStatus('Laying out…');
    await new Promise(requestAnimationFrame);          // let the status paint first
    const result = await Promise.resolve().then(build).catch((error) => { kitFail(error); throw error; });
    const wanted = { base: {}, variants: {} };
    for (const { font, base } of [result].flat().flatMap(fontStringsOf)) {
      const { family, weight, style } = parseFont(font);
      const key = `${family}|${weight}|${style}`;
      if (tried.has(key) || hasFace(family, weight, style)) continue;
      tried.add(key);
      (wanted[base ? 'base' : 'variants'][family] ??= []).push(`${weight}${style === 'italic' ? 'i' : ''}`);
    }
    if (Object.keys(wanted.base).length) {
      console.warn(`[cookbook] FONTS does not list ${JSON.stringify(wanted.base)}: loading them.`);
    }
    const added = await loadFonts(wanted.base, text) + await loadFonts(wanted.variants, text, { optional: true });
    if (added === 0) return result;
    clearMeasurementCache();
  }
  throw new Error('The fonts did not settle after three builds.');
}

/** Every font string of the layout; `base` marks a block's own face. */
function fontStringsOf(doc) {
  const found = new Map();
  const walk = (node) => {
    if (!node || typeof node !== 'object') return;
    if (Array.isArray(node)) { node.forEach(walk); return; }
    for (const [key, value] of Object.entries(node)) {
      if (typeof value === 'string' && /fontString$/i.test(key)) {
        found.set(value, found.get(value) || key === 'fontString');
      } else if (value && typeof value === 'object') walk(value);
    }
  };
  walk(doc.pages);
  walk(doc.blocks);
  return [...found].map(([font, base]) => ({ font, base }));
}

/** '700 37.5px Open Sans' / 'italic 400 13px "Source Serif 4"' → { family, weight, style }.
 *  A string with no weight ('95.8px Young Serif', from a design text) is 400. */
function parseFont(font) {
  const m = /^(?:(italic|oblique)\s+)?(?:small-caps\s+)?(?:(\d+|bold|normal)\s+)?[\d.]+px\s+(.+)$/.exec(font.trim());
  if (!m) throw new Error(`Unexpected font string: ${font}`);
  const weight = m[2] === 'bold' ? 700 : !m[2] || m[2] === 'normal' ? 400 : Number(m[2]);
  return { family: m[3].replace(/^["']|["']$/g, ''), weight, style: m[1] ? 'italic' : 'normal' };
}

/** A loaded FontFace covers this family, weight and style (fonts.check() would
 *  also say yes for families nobody declared). */
function hasFace(family, weight, style) {
  for (const face of document.fonts) {
    if (face.status !== 'loaded' || face.style !== style) continue;
    if (face.family.replace(/^["']|["']$/g, '') !== family) continue;
    const [low, high = low] = face.weight.split(' ').map(Number);
    if (weight >= low && weight <= high) return true;
  }
  return false;
}

/** The files beyond latin `text` needs that `meta`'s family ships. */
function kitSubsetsFor(text, meta) {
  return [[/[Ā-˿ᴀ-ᶿḀ-ỿ†ℓⱠ-Ɀ꜠-ꟿ]/u, 'latin-ext'], [/[Ͱ-Ͽ]/u, 'greek']]
    .filter(([re, x]) => re.test(text) && meta?.subsets?.includes(x)).map(([, x]) => x);
}

/** Fontsource's id for a family: 'Source Serif 4' → 'source-serif-4'. */
function fontsourceId(family) { return family.toLowerCase().replace(/\s+/g, '-'); }

/** The family's Fontsource metadata (weights, styles, subsets), or null. */
function fontsourceMeta(family) {
  fontsourceMeta.cache ??= new Map();
  const id = fontsourceId(family);
  if (!fontsourceMeta.cache.has(id)) {
    fontsourceMeta.cache.set(id, fetch(`https://api.fontsource.org/v1/fonts/${id}`)
      .then((res) => (res.ok ? res.json() : null), () => null));
  }
  return fontsourceMeta.cache.get(id);
}

// ─── Kit · viewer v1 ── the same in every recipe · postext.dev/cookbook
/** The pages as spreads on a dark desk, page 1 alone, then verso | recto,
 *  each painted when it scrolls near. */
function showPages(docs, { title, width = 460 } = {}) {
  const root = viewer(title);
  const pages = [docs].flat().flatMap((doc) =>
    doc.pages.map((page) => ({ doc, page, n: (doc.pageIndexOffset ?? 0) + page.index })));
  const spreads = [];
  let verso = null;
  for (const p of pages) {
    if (p.n % 2 === 1) { if (verso) spreads.push([verso, null]); verso = p; }
    else { spreads.push([verso, p]); verso = null; }
  }
  if (verso) spreads.push([verso, null]);
  const density = Math.min(window.devicePixelRatio || 1, 2);
  showPages.painter?.disconnect();
  const painter = new IntersectionObserver((entries) => {
    for (const { isIntersecting, target } of entries) {
      if (!isIntersecting) continue;
      painter.unobserve(target);
      const { doc, page } = target.postext;
      renderPageToCanvas(page, doc, target, { scale: (width * density) / page.width });
    }
  }, { rootMargin: '800px' });
  showPages.painter = painter;
  root.replaceChildren(...spreads.map((pair) => {
    const spread = document.createElement('div');
    spread.className = 'pt-spread';
    for (const p of pair) {
      const figure = document.createElement('figure');
      if (p) {
        const label = p.page.pageLabel || String(p.n + 1);
        const canvas = document.createElement('canvas');
        canvas.postext = p;
        canvas.style.aspectRatio = `${p.page.width} / ${p.page.height}`;
        canvas.setAttribute('role', 'img');
        canvas.setAttribute('aria-label', `Page ${label}`);
        const folio = document.createElement('figcaption');
        folio.textContent = label;
        figure.append(canvas, folio);
        painter.observe(canvas);
      } else figure.className = 'pt-blank';
      spread.append(figure);
    }
    return spread;
  }));
  kitStatus(`${pages.length} ${pages.length === 1 ? 'page' : 'pages'}`);
  document.documentElement.dataset.postext = 'ready';
  return pages.length;
}

/** The desk, the bar and the error reporting, created once. */
function viewer(title) {
  if (!document.getElementById('pt-kit')) {
    document.head.insertAdjacentHTML('beforeend', `<style id="pt-kit">
      :root { color-scheme: dark; }
      body { margin: 0; background: #0e1014; color: #b9bcc4; font: 13px/1.45 system-ui, sans-serif; }
      #pt-bar { position: sticky; top: 0; z-index: 1; display: flex; flex-wrap: wrap; align-items: center;
        gap: 6px 16px; padding: 10px 16px; background: rgb(14 16 20 / .92); backdrop-filter: blur(6px);
        border-bottom: 1px solid #23262d; }
      #pt-bar strong { color: #f4f1ea; font-weight: 600; }
      #pt-actions { display: flex; gap: 12px; margin-left: auto; }
      #pt-actions a, #pt-actions button { color: #d8a21a; font: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
      #pages { display: grid; justify-items: center; gap: 48px; padding: 32px 16px 72px; }
      .pt-spread { display: flex; }
      .pt-spread figure { margin: 0; width: min(460px, 44vw); }
      .pt-spread canvas { display: block; width: 100%; background: #fff;
        box-shadow: 0 1px 2px rgb(0 0 0 / .5), 0 22px 44px -16px rgb(0 0 0 / .8); }
      .pt-spread figure:first-child canvas { box-shadow: inset -14px 0 14px -14px rgb(0 0 0 / .18), 0 1px 2px rgb(0 0 0 / .5), 0 22px 44px -16px rgb(0 0 0 / .8); }
      .pt-spread figcaption { margin-top: 10px; text-align: center; font: 600 10px/1 system-ui, sans-serif;
        letter-spacing: .18em; text-transform: uppercase; color: #6c7079; }
      .pt-blank { visibility: hidden; }
      @media (max-width: 760px) {
        .pt-spread { flex-direction: column; gap: 32px; }
        .pt-spread figure { width: min(460px, 92vw); }
        .pt-blank { display: none; }
      }
    </style>`);
    document.body.insertAdjacentHTML('afterbegin',
      '<header id="pt-bar"><strong id="pt-title"></strong><span id="pt-status" role="status"></span><span id="pt-actions"></span></header>');
    document.getElementById('pt-title').textContent = document.title || 'Postext';
    addEventListener('error', (event) => kitFail(event.error ?? event.message));
    addEventListener('unhandledrejection', (event) => kitFail(event.reason));
  }
  if (title) document.getElementById('pt-title').textContent = title;
  return document.getElementById('pages')
    ?? document.body.appendChild(Object.assign(document.createElement('main'), { id: 'pages' }));
}

function kitStatus(text) {
  viewer();
  document.getElementById('pt-status').textContent = text;
}

function kitFail(error) {
  document.documentElement.dataset.postext = 'error';
  kitStatus(`Error: ${error?.message ?? error}`);
}

// ─── Kit · pdf v2 ── the same in every recipe that exports a PDF
/** The Fontsource files the screen used, as TrueType: the nearest weight the
 *  family ships, upright if it has no italic; latin, then what the face's
 *  letters need (kitSubsetsFor). */
async function fontsourceProvider(family, weight, style, request) {
  const id = fontsourceId(family);
  const meta = await fontsourceMeta(family);
  const weights = meta?.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && meta && !meta.styles.includes('italic') ? 'normal' : style;
  const text = String.fromCodePoint(...(request?.codePoints ?? []));
  const more = kitSubsetsFor(text, meta);
  const files = await Promise.all(['latin', ...more].map(async (subset) => {
    const res = await fetch(`https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-${subset}-${w}-${s}.woff2`);
    if (!res.ok) throw new Error(`Fontsource has no ${family} ${w} ${s} ${subset}`);
    return decompressWoff2(new Uint8Array(await res.arrayBuffer()));
  }));
  return files.length === 1 ? files[0] : files;
}

/** A "Build the PDF" button; then "Open the PDF" (a new tab: CodePen's frame
 *  shows no PDFs) and a download link. */
function offerPdf(makePdf, filename) {
  viewer();
  const button = Object.assign(document.createElement('button'), { type: 'button', textContent: 'Build the PDF' });
  button.dataset.postextPdf = filename;
  button.addEventListener('click', async () => {
    button.disabled = true;
    button.textContent = 'Building the PDF…';
    try {
      const bytes = await makePdf();
      const url = URL.createObjectURL(new Blob([bytes], { type: 'application/pdf' }));
      const size = `${Math.max(1, Math.round(bytes.length / 1024))} KB`;
      button.replaceWith(
        Object.assign(document.createElement('a'), { href: url, target: '_blank', rel: 'noopener', textContent: 'Open the PDF ↗' }),
        Object.assign(document.createElement('a'), { href: url, download: filename, textContent: `Download ${filename} · ${size}` }));
    } catch (error) {
      button.disabled = false;
      button.textContent = 'Build the PDF';
      kitFail(error);
    }
  });
  document.getElementById('pt-actions').append(button);
}

// ─── Kit · images v1 ── recipes with pictures · postext.dev/cookbook
/** Registers a photo or PNG for the canvas and keeps its bytes for the PDF.
 *  fetch → ImageBitmap never taints the canvas (a plain cross-origin <img> would). */
async function loadImage(fileId, url) {
  const res = await fetch(url);
  if (!res.ok) throw new Error(`Image not found (${res.status}): ${url}`);
  const bytes = new Uint8Array(await res.arrayBuffer());
  registerResourceImage(fileId, await createImageBitmap(new Blob([bytes])));
  (loadImage.bytes ??= new Map()).set(fileId, bytes);
}

/** Registers SVG markup (drawn in code, or fetched) as a vector image. */
async function loadSvg(fileId, svg) {
  const img = new Image();
  img.src = `data:image/svg+xml;charset=utf-8,${encodeURIComponent(svg)}`;
  await img.decode();
  registerResourceImage(fileId, img);
  (loadImage.bytes ??= new Map()).set(fileId, new TextEncoder().encode(svg));
}

/** renderToPdf({ resourceBytes: imageBytes }) */
function imageBytes(fileId) { return loadImage.bytes?.get(fileId); }

/** renderToHtml({ resourceImageUrl: imageUrl }) */
function imageUrl(fileId) {
  const bytes = imageBytes(fileId);
  if (!bytes) return undefined;
  imageUrl.urls ??= new Map();
  if (!imageUrl.urls.has(fileId)) {
    const type = /\.svg$/i.test(fileId) ? 'image/svg+xml' : /\.png$/i.test(fileId) ? 'image/png' : 'image/jpeg';
    imageUrl.urls.set(fileId, URL.createObjectURL(new Blob([bytes], { type })));
  }
  return imageUrl.urls.get(fileId);
}

// ─── Kit · cjk v1 ── Chinese, Japanese and Korean books · postext.dev/cookbook
// Fontsource ships a CJK family as about a hundred files per weight, each
// declared in its stylesheet with the unicode-range it covers. The screen
// loads the files the sample touches; the PDF gets the same files for the
// characters its pages set in each face, and embeds each as a subset.
// A book bound on the right (vertical text) is shown with its spreads
// mirrored: page 1 alone on the left of the spine, then [3 | 2].

/** The files of a Fontsource face, read from its stylesheet: { url, range,
 *  ranges }, the last declared first (the order the browser tries them in). */
function cjkSlices(family, weight, style) {
  cjkSlices.cache ??= new Map();
  const id = fontsourceId(family);
  const css = `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/${weight}${style === 'italic' ? '-italic' : ''}.css`;
  if (!cjkSlices.cache.has(css)) {
    cjkSlices.cache.set(css, fetch(css)
      .then((res) => {
        if (!res.ok) throw new Error(`Fontsource has no ${family} ${weight} ${style} (${res.status})`);
        return res.text();
      })
      .then((text) => [...text.matchAll(/@font-face\s*{([^}]*)}/g)].map(([, rule]) => {
        const range = /unicode-range:\s*([^;]+);/.exec(rule)?.[1].trim() ?? 'U+0-10FFFF';
        const ranges = range.split(',').map((part) => {
          const [lo, hi = lo] = part.trim().slice(2).split('-');
          return [parseInt(lo, 16), parseInt(hi, 16)];
        });
        return { url: new URL(/url\(([^)]+?\.woff2)\)/.exec(rule)[1], css).href, range, ranges };
      }).reverse()));
  }
  return cjkSlices.cache.get(css);
}

/** The file of `slices` that holds code point `cp`, if any. */
function cjkSliceFor(slices, cp) {
  return slices.find((slice) => slice.ranges.some(([lo, hi]) => cp >= lo && cp <= hi));
}

/** Whether Fontsource serves `family` as a Chinese, Japanese or Korean
 *  family (its subsets name the script). Fails when the API does not
 *  answer: a CJK face taken for a Latin one would paint in a system face. */
async function isCjkFamily(family) {
  const meta = await fontsourceMeta(family);
  if (!meta) throw new Error(`api.fontsource.org did not describe ${family}: reload to try again`);
  return !!meta.subsets?.some((subset) => /^(chinese|japanese|korean)/.test(subset));
}

/** faces = { 'Noto Serif TC': ['400', '700'] }, as for loadFonts: the
 *  whole FONTS object may be passed, its other families are left to
 *  loadFonts. Adds one FontFace per file of each CJK face with its
 *  unicodeRange, then loads the files `text` touches. `text` is what the
 *  faces set: the sample for the text face; a book in several voices calls
 *  it once per voice (loadCjkFonts({ 'LXGW WenKai TC': ['400'] }, quotes)),
 *  so the heading and quotation faces fetch and check only their own
 *  characters. Fails when a character of `text` is in no file of a face.
 *  List every weight the pages use: a weight left to buildWithFonts gets
 *  the latin file only. With { vertical: true } it also loads each
 *  family's vertical forms (brackets, quotes, pause marks) for the canvas,
 *  which needs loadVerticalAlternates imported from postext. Resolves to
 *  the number of files loaded. */
async function loadCjkFonts(faces, text, { vertical = false } = {}) {
  kitStatus('Loading fonts…');
  let loaded = 0;
  try {
    if (vertical && typeof loadVerticalAlternates !== 'function') {
      throw new Error('loadCjkFonts(…, { vertical: true }) needs loadVerticalAlternates imported from postext');
    }
    for (const [family, specs] of Object.entries(faces)) {
      if (!(await isCjkFamily(family))) continue;
      const twin = [];
      for (const spec of new Set(specs)) {
        const weight = parseInt(spec, 10);
        const style = spec.endsWith('i') ? 'italic' : 'normal';
        const slices = await cjkSlices(family, weight, style);
        const missing = [...new Set(text)].filter((ch) => /\S/.test(ch) && !cjkSliceFor(slices, ch.codePointAt(0)));
        if (missing.length) {
          throw new Error(`${family} ${spec} has no file for ${missing.slice(0, 12).join(' ')}: `
            + `give each face the text it sets (loadCjkFonts({ '${family}': ['${spec}'] }, text))`);
        }
        for (const slice of slices) {
          document.fonts.add(new FontFace(family, `url(${slice.url}) format('woff2')`,
            { weight: String(weight), style, unicodeRange: slice.range }));
          twin.push({ source: slice.url, weight: String(weight), style, unicodeRange: slice.range });
        }
        const font = `${style === 'italic' ? 'italic ' : ''}${weight} 16px "${family}"`;
        loaded += (await document.fonts.load(font, text)).length;
        if (!document.fonts.check(font, text)) throw new Error(`${family} ${spec} did not load for the sample`);
      }
      // The same files under a twin name with the `vert` feature on: the
      // canvas paints the punctuation of vertical lines with it.
      if (vertical && twin.length) await loadVerticalAlternates(family, twin);
    }
  } catch (error) {
    kitFail(error);
    throw error;
  }
  return loaded;
}

/** The PDF font provider for recipes with CJK faces: a family whose
 *  Fontsource subsets are Chinese, Japanese or Korean gets the files that
 *  hold the characters its pages set (`request.codePoints`); any other
 *  family gets the latin file fontsourceProvider fetches (the "pdf" block)
 *  and, when the face sets letters only latin-ext has, that file too. */
async function cjkPdfProvider(family, weight, style, request) {
  if (!(await isCjkFamily(family))) return cjkLatinPdfFiles(family, weight, style, request);
  const meta = await fontsourceMeta(family);
  const weights = meta.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && !meta.styles.includes('italic') ? 'normal' : style;
  const slices = await cjkSlices(family, w, s);
  const picked = new Set();
  for (const cp of request?.codePoints ?? []) {
    const slice = cjkSliceFor(slices, cp);
    if (slice) picked.add(slice);
  }
  if (!picked.size) picked.add(slices[0]);
  return Promise.all(slices.filter((slice) => picked.has(slice)).map(async (slice) => {
    const res = await fetch(slice.url);
    if (!res.ok) throw new Error(`Fontsource file ${slice.url} (${res.status})`);
    return decompressWoff2(new Uint8Array(await res.arrayBuffer()));
  }));
}

/** A Latin family set next to the CJK faces: its latin file, then its
 *  latin-ext file when the face sets letters only latin-ext has (ō ū in
 *  Hepburn rōmaji, ǎ in pinyin), the file loadFonts adds on screen for
 *  them. Latin comes first: postext-pdf draws a character from the first
 *  file that has it, as the browser takes a character both files hold from
 *  latin. A face Fontsource ships without latin-ext, or whose file does
 *  not come, gets latin alone, and the PDF names the letters it lacks. */
async function cjkLatinPdfFiles(family, weight, style, request) {
  const meta = await fontsourceMeta(family);
  const beyond = [...(request?.codePoints ?? [])].some(cjkLatinExtOnly);
  if (!beyond || !meta?.subsets?.includes('latin-ext')) return fontsourceProvider(family, weight, style);
  const weights = meta.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && !meta.styles.includes('italic') ? 'normal' : style;
  const id = fontsourceId(family);
  const url = `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-latin-ext-${w}-${s}.woff2`;
  const [latin, ext] = await Promise.all([fontsourceProvider(family, weight, style), fetch(url)
    .then(async (res) => (res.ok ? decompressWoff2(new Uint8Array(await res.arrayBuffer())) : null), () => null)]);
  return ext ? [latin, ext] : latin;
}

/** Whether code point `cp` is in Fontsource's latin-ext file and not in
 *  its latin file: Latin Extended-A and -B, IPA, the spacing modifiers and
 *  Latin Extended Additional (loadFonts's test for latin-ext), less the
 *  few latin holds too (ı Œ œ ʻ ʼ ˆ ˚ ˜). */
function cjkLatinExtOnly(cp) {
  if (!((cp >= 0x100 && cp <= 0x2ff) || (cp >= 0x1e00 && cp <= 0x1eff))) return false;
  return ![0x131, 0x152, 0x153, 0x2bb, 0x2bc, 0x2c6, 0x2da, 0x2dc].includes(cp);
}

/** showPages for a book bound on either edge. A right-bound book (the
 *  document says so: doc.binding is 'right' for page.binding 'right' and
 *  for vertical text) lies on the desk as it opens: page 1 alone on the
 *  left of the spine, then [3 | 2], the spine shade on each page's inner
 *  edge. `binding` ('left' | 'right') overrides the document's. */
function showBook(docs, { binding, ...options } = {}) {
  const count = showPages(docs, options);
  const right = (binding ?? [docs].flat()[0]?.binding) === 'right';
  if (!document.getElementById('pt-kit-cjk')) {
    // The pages keep direction ltr: a canvas draws text in the direction its
    // element inherits, and under rtl each run would end where the engine
    // starts it, its brackets mirrored.
    document.head.insertAdjacentHTML('beforeend', `<style id="pt-kit-cjk">
      .pt-spread[dir="rtl"] canvas { direction: ltr; }
      .pt-spread[dir="rtl"] figure:first-child canvas { box-shadow: inset 14px 0 14px -14px rgb(0 0 0 / .18),
        0 1px 2px rgb(0 0 0 / .5), 0 22px 44px -16px rgb(0 0 0 / .8); }
    </style>`);
  }
  // Each pair stays [verso, recto] in the page; right to left, the verso
  // sits on the right. Phones stack the pages in reading order either way.
  for (const spread of document.querySelectorAll('#pages > .pt-spread')) spread.dir = right ? 'rtl' : 'ltr';
  document.getElementById('pages').dataset.binding = right ? 'right' : 'left';
  return count;
}

// ─── Kit · arabic v1 ── Arabic-script faces · postext.dev/cookbook
// Fontsource ships an Arabic family as one file per subset and weight: the
// `arabic` file holds the letters, the harakat, the Arabic-Indic digits, the
// Arabic punctuation and the presentation forms; `latin` and `latin-ext`
// hold the rest. loadFonts loads the latin files; this block adds the arabic
// file of every Arabic family, for the canvas and for the PDF, which shapes
// the letters with HarfBuzz from the same bytes.

/** The code points of Fontsource's `arabic` subset, as its stylesheets
 *  declare them (the same unicode-range the browser picks the file by). A
 *  function, not a const: the kit is inlined after the recipe's top-level
 *  awaits, and a const read before its line throws, where a function
 *  declaration is hoisted. */
function arabicRange() {
  return 'U+0600-06FF,U+0750-077F,U+0870-088E,U+0890-0891,U+0897-08E1,U+08E3-08FF,'
    + 'U+200C-200E,U+2010-2011,U+204F,U+2E41,U+FB50-FDFF,U+FE70-FE74,U+FE76-FEFC,U+102E0-102FB,'
    + 'U+10E60-10E7E,U+10EC2-10EC4,U+10EFC-10EFF,U+1EE00-1EEFF';
}

/** Whether code point `cp` is in the arabic file. */
function inArabicRange(cp) {
  inArabicRange.ranges ??= arabicRange().split(',').map((part) => {
    const [lo, hi = lo] = part.slice(2).split('-');
    return [parseInt(lo, 16), parseInt(hi, 16)];
  });
  return inArabicRange.ranges.some(([lo, hi]) => cp >= lo && cp <= hi);
}

/** Whether Fontsource serves `family` with an `arabic` subset. Fails when
 *  the API does not answer: an Arabic face taken for a Latin one would set
 *  its letters in a system face. */
async function isArabicFamily(family) {
  const meta = await fontsourceMeta(family);
  if (!meta) throw new Error(`api.fontsource.org did not describe ${family}: reload to try again`);
  return !!meta.subsets?.includes('arabic');
}

/** The arabic file of a face. */
function arabicFileUrl(family, weight, style) {
  const id = fontsourceId(family);
  return `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-arabic-${weight}-${style}.woff2`;
}

/** faces = { Amiri: ['400', '700'] }, as for loadFonts, after it: the whole
 *  FONTS object may be passed, its families without an arabic subset are
 *  left alone. Adds the arabic file of every listed weight of each Arabic
 *  family (the latin files come from loadFonts) and loads it. `text` is
 *  the sample: fails when it holds an Arabic-script character the arabic
 *  file does not cover. List every weight the pages set in Arabic: a weight
 *  left to buildWithFonts gets the latin file only, and its Arabic letters
 *  fall back to a system face. Resolves to the number of files loaded. */
async function loadArabicFonts(faces, text = '') {
  kitStatus('Loading fonts…');
  let loaded = 0;
  try {
    const outside = [...new Set(text)].filter((ch) => /\p{Script=Arabic}/u.test(ch) && !inArabicRange(ch.codePointAt(0)));
    if (outside.length) throw new Error(`Fontsource's arabic files have no ${outside.slice(0, 12).join(' ')}`);
    for (const [family, specs] of Object.entries(faces)) {
      if (!(await isArabicFamily(family))) continue;
      for (const spec of new Set(specs)) {
        const weight = parseInt(spec, 10);
        const style = spec.endsWith('i') ? 'italic' : 'normal';
        const face = new FontFace(family, `url(${arabicFileUrl(family, weight, style)}) format('woff2')`,
          { weight: String(weight), style, unicodeRange: arabicRange() });
        document.fonts.add(await face.load().catch(() => {
          throw new Error(`Fontsource has no arabic file for ${family} ${weight} ${style}`);
        }));
        loaded++;
      }
    }
  } catch (error) {
    kitFail(error);
    throw error;
  }
  return loaded;
}

/** The PDF font provider for recipes with Arabic faces: a family with an
 *  arabic subset gets its arabic file when its pages set Arabic letters
 *  (`request.codePoints`), then its latin file, and its latin-ext file for
 *  the letters beyond latin (transliteration: ā ḥ ʿ). The arabic file comes
 *  first: it also holds the space and the brackets, so a line of Arabic is
 *  shaped as one run and not cut at every space. Any other family goes to
 *  fontsourceProvider (the "pdf" block). */
async function arabicPdfProvider(family, weight, style, request) {
  if (!(await isArabicFamily(family))) return fontsourceProvider(family, weight, style, request);
  const meta = await fontsourceMeta(family);
  const weights = meta.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && !meta.styles.includes('italic') ? 'normal' : style;
  const wanted = [...(request?.codePoints ?? [])];
  const id = fontsourceId(family);
  const urls = [];
  if (!wanted.length || wanted.some(inArabicRange)) urls.push(arabicFileUrl(family, w, s));
  urls.push(`https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-latin-${w}-${s}.woff2`);
  if (meta.subsets.includes('latin-ext') && wanted.some((cp) => /[Ā-˿Ḁ-ỿ]/u.test(String.fromCodePoint(cp)))) {
    urls.push(`https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-latin-ext-${w}-${s}.woff2`);
  }
  return Promise.all(urls.map(async (url) => {
    const res = await fetch(url);
    if (!res.ok) throw new Error(`Fontsource file ${url} (${res.status})`);
    return decompressWoff2(new Uint8Array(await res.arrayBuffer()));
  }));
}

// ─── Kit · comics v1 ── comic pages · postext.dev/cookbook
// The engine letters a comic in a face per language (defaultComicFont:
// Comic Neue, Zen Antique for Japanese, Noto Sans SC, LXGW WenKai TC,
// Playpen Sans Arabic; defaultComicSfxFont: Bangers, Dela Gothic One,
// ZCOOL KuaiLe, Lalezar) and asks for the bold of a shout or a sound effect
// and the italic of an inner voice. Most of these faces ship one weight and
// no italic: this block declares the file Fontsource does ship for those
// variants, so the canvas measures and paints the letters the PDF embeds
// (the providers snap to the shipped file) and not a bold or a slant the
// browser makes up. It also turns the art manifest into panel resources.

/** faces = { 'Comic Neue': ['400', '700'], Bangers: ['400'] }, as for
 *  loadFonts, after it (and after loadCjkFonts or loadArabicFonts for the
 *  faces of those scripts); the whole FONTS object may be passed. List in
 *  FONTS only what Fontsource ships (Bangers: ['400']): loadFonts fails on
 *  the rest. For each family, the regular, bold, italic and bold italic it
 *  lacks are declared with its nearest file (the regular for the bold, the
 *  upright for the italic) and loaded for `text`. A CJK face needs the cjk
 *  block; an Arabic face setting Arabic, the arabic block. Resolves to the
 *  number of variants added. */
async function loadComicFonts(faces, text = '') {
  kitStatus('Loading fonts…');
  let added = 0;
  try {
    for (const family of Object.keys(faces)) {
      const meta = await fontsourceMeta(family);
      if (!meta) throw new Error(`api.fontsource.org did not describe ${family}: reload to try again`);
      const weights = meta.weights?.length ? meta.weights : [400, 700];
      const styles = meta.styles?.length ? meta.styles : ['normal'];
      for (const [weight, style] of [[400, 'normal'], [700, 'normal'], [400, 'italic'], [700, 'italic']]) {
        if ((weights.includes(weight) && styles.includes(style)) || hasFace(family, weight, style)) continue;
        const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
        const s = style === 'italic' && styles.includes('italic') ? 'italic' : 'normal';
        for (const { url, range } of await comicFaceFiles(family, w, s, meta, text)) {
          document.fonts.add(new FontFace(family, `url(${url}) format('woff2')`,
            { weight: String(weight), style, unicodeRange: range }));
        }
        await document.fonts.load(`${style === 'italic' ? 'italic ' : ''}${weight} 16px "${family}"`, text || 'A');
        added++;
      }
    }
  } catch (error) {
    kitFail(error);
    throw error;
  }
  return added;
}

/** The files of a shipped face ({ url, range }): a CJK face's slices (the
 *  cjk block reads them from its stylesheet), else latin, the latin-ext
 *  and greek files `text` needs, and the arabic file when `text` holds
 *  Arabic. */
async function comicFaceFiles(family, weight, style, meta, text) {
  if (meta.subsets?.some((subset) => /^(chinese|japanese|korean)/.test(subset))) {
    if (typeof cjkSlices !== 'function') throw new Error(`${family} is a CJK face: list the cjk kit block`);
    return (await cjkSlices(family, weight, style)).map(({ url, range }) => ({ url, range }));
  }
  const id = fontsourceId(family);
  const file = (subset) => `https://cdn.jsdelivr.net/npm/@fontsource/${id}@5/files/${id}-${subset}-${weight}-${style}.woff2`;
  const files = ['latin', ...kitSubsetsFor(text, meta)].map((subset) => ({ url: file(subset), range: comicRange(subset) }));
  if (meta.subsets?.includes('arabic') && /\p{Script=Arabic}/u.test(text)) {
    if (typeof arabicRange !== 'function') throw new Error(`${family} sets Arabic: list the arabic kit block`);
    files.unshift({ url: file('arabic'), range: arabicRange() });
  }
  return files;
}

/** The unicode-range loadFonts gives a Fontsource file. A function, not a
 *  const: the kit is inlined after the recipe's top-level awaits. */
function comicRange(subset) {
  return {
    latin: 'U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,'
      + 'U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD',
    'latin-ext': 'U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,'
      + 'U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF',
    greek: 'U+0370-03FF',
  }[subset];
}

/** The PDF font provider of a comic in any script: a CJK face goes to
 *  cjkPdfProvider, an Arabic face to arabicPdfProvider, any other to
 *  fontsourceProvider (the "pdf" block). Each embeds the shipped weight
 *  and style nearest to the one asked for, the file loadComicFonts
 *  declared for the canvas. */
async function comicPdfProvider(family, weight, style, request) {
  const subsets = (await fontsourceMeta(family))?.subsets ?? [];
  if (subsets.some((subset) => /^(chinese|japanese|korean)/.test(subset))) {
    if (typeof cjkPdfProvider !== 'function') throw new Error(`${family} is a CJK face: list the cjk kit block`);
    return cjkPdfProvider(family, weight, style, request);
  }
  if (subsets.includes('arabic') && typeof arabicPdfProvider === 'function') {
    return arabicPdfProvider(family, weight, style, request);
  }
  return fontsourceProvider(family, weight, style, request);
}

/** A panel picture as a resource for art= (and pop=): loads `url`
 *  (write asset('lh-arrive.jpg') in the call, so the lint checks the file)
 *  and declares it with `meta`, its entry in the art manifest:
 *  { width, height, alt, safeArea, anchors, avoid }. The safe area is what
 *  every crop keeps, the anchors the speakers' mouths, heads and faces,
 *  the avoid zones what no balloon covers; all in fractions of the picture,
 *  the same in every language. Without width and height, the picture's own
 *  size. Needs the images block. Resolves to the resource. */
async function comicPanel(id, url, meta = {}) {
  const fileId = decodeURIComponent(url.split('/').pop());
  await loadImage(fileId, url);
  let { width, height } = meta;
  if (!width || !height) {
    const bitmap = await createImageBitmap(new Blob([imageBytes(fileId)]));
    ({ width, height } = bitmap);
    bitmap.close();
  }
  return {
    id, typeId: meta.typeId ?? 'figure', kind: 'bitmap', createdAt: 0, updatedAt: 0,
    bitmap: { fileId, format: /\.png$/i.test(fileId) ? 'png' : 'jpeg', width, height },
    ...(meta.alt && { altText: meta.alt }),
    ...(meta.safeArea && { safeArea: meta.safeArea }),
    ...(meta.anchors?.length && { anchors: meta.anchors }),
    ...(meta.avoid?.length && { avoid: meta.avoid }),
  };
}

// ─── /Kit ───────────────────────────────────────────────────────────────────────