/**
 * The sheet playground.
 *
 * This is not a mock-up of the print studio: it imports `engine/printlayout.ts`
 * and `engine/paper.ts` verbatim from the Klarbild repository and runs them in
 * your browser. The numbers you see here are the numbers the application
 * computes, and the PDF you download is laid out by the same arithmetic — it is
 * drawn with pdf-lib on this page rather than with sharp on a server, which is
 * why it carries outlines instead of photographs.
 *
 * Nothing is uploaded and there is no server behind this page.
 */

import { layout, cutMarks, effectiveGap, recommendedGap, type PlaceSpec, type SheetSpec, type MarkMode } from '../engine/printlayout';
import { PAPERS, PHOTO_SIZES, labelMm } from '../engine/paper';

/** German writes 29,7 cm where English writes 29.7 cm. Only the separator differs. */
function localiseNumbers(text: string, lang: string): string {
  return lang === 'de' ? text.replace(/(\d),(?=\d)/g, '$1\u2009').replace(/(\d)\.(?=\d)/g, '$1,') : text;
}

const MM_PT = 72 / 25.4;

type State = {
  paperId: string;
  landscape: boolean;
  sizeId: string;
  count: number;
  marks: MarkMode;
  bleedMm: number;
  marginMm: number;
  allowRotate: boolean;
};

const state: State = {
  paperId: 'A4',
  landscape: false,
  sizeId: 'P35x45',
  count: 8,
  marks: 'corner',
  bleedMm: 0,
  marginMm: 5,
  allowRotate: true,
};

/* ------------------------------------------------------------------ helpers */

function paper() {
  const p = PAPERS.find((x) => x.id === state.paperId) ?? PAPERS[2];
  return state.landscape ? { ...p, w: p.h, h: p.w } : p;
}

function size() {
  return PHOTO_SIZES.find((x) => x.id === state.sizeId) ?? PHOTO_SIZES[0];
}

function sheetSpec(): SheetSpec {
  const p = paper();
  return {
    wMm: p.w,
    hMm: p.h,
    marginMm: state.marginMm,
    gapMm: recommendedGap(state.marks, state.bleedMm),
    bleedMm: state.bleedMm,
    center: true,
  };
}

function placeSpec(): PlaceSpec {
  const s = size();
  return { id: 'cell', wMm: s.w, hMm: s.h, count: state.count, allowRotate: state.allowRotate };
}

function compute() {
  const sheet = sheetSpec();
  const result = layout([placeSpec()], sheet);
  return { sheet, result };
}

/* ------------------------------------------------------------------- render */

const NS = 'http://www.w3.org/2000/svg';

function el(name: string, attrs: Record<string, string | number>) {
  const n = document.createElementNS(NS, name);
  for (const [k, v] of Object.entries(attrs)) n.setAttribute(k, String(v));
  return n;
}

function drawSheet(host: SVGSVGElement, pageIndex = 0) {
  const { sheet, result } = compute();
  const page = result.pages[pageIndex];
  host.setAttribute('viewBox', `0 0 ${sheet.wMm} ${sheet.hMm}`);
  host.replaceChildren();

  host.appendChild(el('rect', { x: 0, y: 0, width: sheet.wMm, height: sheet.hMm, fill: '#fff' }));
  // The printer's non-printable margin, as a hairline so you can see what is lost.
  host.appendChild(el('rect', {
    x: sheet.marginMm, y: sheet.marginMm,
    width: Math.max(0, sheet.wMm - 2 * sheet.marginMm),
    height: Math.max(0, sheet.hMm - 2 * sheet.marginMm),
    fill: 'none', stroke: 'var(--line)', 'stroke-width': 0.2, 'stroke-dasharray': '2 2',
  }));

  if (!page) return { sheet, result };

  page.placements.forEach((pl, i) => {
    const g = el('g', { class: 'cell', style: `--i:${i}` });
    if (sheet.bleedMm) {
      g.appendChild(el('rect', {
        x: pl.x - sheet.bleedMm, y: pl.y - sheet.bleedMm,
        width: pl.w + 2 * sheet.bleedMm, height: pl.h + 2 * sheet.bleedMm,
        fill: 'var(--bleed)',
      }));
    }
    g.appendChild(el('rect', { x: pl.x, y: pl.y, width: pl.w, height: pl.h, fill: 'var(--cellfill)' }));
    // A stand-in for the photograph: a horizon and a disc, so the cell reads as
    // a picture without pretending to be one.
    g.appendChild(el('circle', {
      cx: pl.x + pl.w / 2, cy: pl.y + pl.h * 0.38,
      r: Math.min(pl.w, pl.h) * 0.19, fill: 'var(--cellink)',
    }));
    g.appendChild(el('path', {
      d: `M${pl.x} ${pl.y + pl.h} C ${pl.x + pl.w * 0.12} ${pl.y + pl.h * 0.62}, ${pl.x + pl.w * 0.88} ${pl.y + pl.h * 0.62}, ${pl.x + pl.w} ${pl.y + pl.h} Z`,
      fill: 'var(--cellink)',
    }));
    host.appendChild(g);
  });

  for (const line of cutMarks(page, sheet, { mode: state.marks, lengthMm: 4, offsetMm: 3 })) {
    host.appendChild(el('line', {
      x1: line.x1, y1: line.y1, x2: line.x2, y2: line.y2,
      stroke: 'var(--mark)', 'stroke-width': 0.25,
    }));
  }
  return { sheet, result };
}

/* ---------------------------------------------------------------------- PDF */

async function buildPdf(): Promise<Blob> {
  const { PDFDocument, rgb } = await import('pdf-lib');
  const { sheet, result } = compute();
  const doc = await PDFDocument.create();
  doc.setTitle('Klarbild sheet (demo)');
  doc.setCreator('Klarbild demo — klarbild-demo.heidrich-digital.de');

  for (const page of result.pages) {
    const pg = doc.addPage([sheet.wMm * MM_PT, sheet.hMm * MM_PT]);
    // PDF counts from the bottom left; the layout counts from the top left.
    const flip = (yMm: number, hMm: number) => (sheet.hMm - yMm - hMm) * MM_PT;

    for (const pl of page.placements) {
      if (sheet.bleedMm) {
        pg.drawRectangle({
          x: (pl.x - sheet.bleedMm) * MM_PT,
          y: flip(pl.y - sheet.bleedMm, pl.h + 2 * sheet.bleedMm),
          width: (pl.w + 2 * sheet.bleedMm) * MM_PT,
          height: (pl.h + 2 * sheet.bleedMm) * MM_PT,
          color: rgb(0.925, 0.933, 0.925),
        });
      }
      pg.drawRectangle({
        x: pl.x * MM_PT, y: flip(pl.y, pl.h),
        width: pl.w * MM_PT, height: pl.h * MM_PT,
        borderColor: rgb(0.72, 0.72, 0.70), borderWidth: 0.4,
      });
    }
    for (const line of cutMarks(page, sheet, { mode: state.marks, lengthMm: 4, offsetMm: 3 })) {
      pg.drawLine({
        start: { x: line.x1 * MM_PT, y: (sheet.hMm - line.y1) * MM_PT },
        end: { x: line.x2 * MM_PT, y: (sheet.hMm - line.y2) * MM_PT },
        thickness: 0.25, color: rgb(0.4, 0.4, 0.38),
      });
    }
  }
  return new Blob([await doc.save()], { type: 'application/pdf' });
}

/* ---------------------------------------------------------------------- wire */

interface PgLabels {
  downloadBusy: string;
  noteAllFit: string;
  noteAllFitMulti: string;
  notePartial: string;
  noteNone: string;
}

export function mountPlayground(root: HTMLElement, labels: PgLabels) {
  const lang = document.documentElement.lang || 'en';
  const mm = (w: number, h: number) => localiseNumbers(labelMm(w, h), lang);
  const svg = root.querySelector<SVGSVGElement>('#sheet')!;
  const out = {
    fits: root.querySelector<HTMLElement>('[data-out=fits]')!,
    pages: root.querySelector<HTMLElement>('[data-out=pages]')!,
    cell: root.querySelector<HTMLElement>('[data-out=cell]')!,
    paper: root.querySelector<HTMLElement>('[data-out=paper]')!,
    gap: root.querySelector<HTMLElement>('[data-out=gap]')!,
    note: root.querySelector<HTMLElement>('[data-out=note]')!,
  };

  // Paper and size menus come from the same tables the application uses.
  const paperSel = root.querySelector<HTMLSelectElement>('#paper')!;
  for (const group of [...new Set(PAPERS.map((p) => p.group))]) {
    const og = document.createElement('optgroup');
    og.label = group;
    for (const p of PAPERS.filter((x) => x.group === group)) {
      const o = document.createElement('option');
      o.value = p.id;
      o.textContent = `${p.label} · ${mm(p.w, p.h)}`;
      og.appendChild(o);
    }
    paperSel.appendChild(og);
  }
  paperSel.value = state.paperId;

  const sizeSel = root.querySelector<HTMLSelectElement>('#size')!;
  for (const group of [...new Set(PHOTO_SIZES.map((s) => s.group))]) {
    const og = document.createElement('optgroup');
    og.label = group;
    for (const s of PHOTO_SIZES.filter((x) => x.group === group)) {
      const o = document.createElement('option');
      o.value = s.id;
      o.textContent = s.label;
      og.appendChild(o);
    }
    sizeSel.appendChild(og);
  }
  sizeSel.value = state.sizeId;

  function refresh() {
    const { sheet, result } = drawSheet(svg);
    const s = size();
    const wanted = state.count;
    const placed = result.pages.reduce((n, p) => n + p.placements.length, 0);

    out.fits.textContent = String(placed);
    out.pages.textContent = String(result.pages.length);
    out.cell.textContent = mm(s.w, s.h);
    out.paper.textContent = mm(sheet.wMm, sheet.hMm);
    out.gap.textContent = localiseNumbers(`${effectiveGap(sheet).toFixed(1)} mm`, lang);

    const fill = (t: string) => t
      .replace('{n}', String(wanted))
      .replace('{placed}', String(placed))
      .replace('{pages}', String(result.pages.length))
      .replace('{size}', s.label);

    if (placed === 0) {
      out.note.textContent = fill(labels.noteNone);
      out.note.dataset.tone = 'warn';
    } else if (placed < wanted) {
      out.note.textContent = fill(labels.notePartial);
      out.note.dataset.tone = 'warn';
    } else {
      out.note.textContent = fill(result.pages.length > 1 ? labels.noteAllFitMulti : labels.noteAllFit);
      out.note.dataset.tone = 'ok';
    }
  }

  root.addEventListener('input', (e) => {
    const t = e.target as HTMLInputElement | HTMLSelectElement;
    switch (t.id) {
      case 'paper': state.paperId = t.value; break;
      case 'size': state.sizeId = t.value; break;
      case 'count': state.count = Math.max(1, Math.min(200, Number(t.value) || 1)); break;
      case 'bleed': state.bleedMm = Number(t.value); root.querySelector('[data-val=bleed]')!.textContent = `${state.bleedMm} mm`; break;
      case 'margin': state.marginMm = Number(t.value); root.querySelector('[data-val=margin]')!.textContent = `${state.marginMm} mm`; break;
      default: return;
    }
    refresh();
  });

  root.addEventListener('click', (e) => {
    const b = (e.target as HTMLElement).closest<HTMLButtonElement>('button[data-set]');
    if (!b) return;
    const [key, value] = b.dataset.set!.split(':');
    if (key === 'marks') state.marks = value as MarkMode;
    if (key === 'orientation') state.landscape = value === 'landscape';
    if (key === 'rotate') state.allowRotate = !state.allowRotate;
    for (const sib of root.querySelectorAll<HTMLButtonElement>(`button[data-set^="${key}:"]`)) {
      sib.setAttribute('aria-pressed', String(sib.dataset.set === b.dataset.set));
    }
    if (key === 'rotate') b.setAttribute('aria-pressed', String(state.allowRotate));
    refresh();
  });

  const dl = root.querySelector<HTMLButtonElement>('#download')!;
  dl.addEventListener('click', async () => {
    const label = dl.textContent;
    dl.disabled = true;
    dl.textContent = labels.downloadBusy;
    try {
      const blob = await buildPdf();
      const url = URL.createObjectURL(blob);
      const a = document.createElement('a');
      a.href = url;
      a.download = `klarbild-demo-${state.sizeId}-${state.count}-on-${state.paperId}.pdf`;
      a.click();
      // Revoke late: Safari cancels the download if the URL dies too early.
      setTimeout(() => URL.revokeObjectURL(url), 10_000);
    } finally {
      dl.disabled = false;
      dl.textContent = label;
    }
  });

  refresh();
}