import type { APIRoute } from 'astro';
import { layout, cutMarks, effectiveGap, type PlaceSpec, type SheetSpec, type MarkMode } from '../../../lib/printlayout';
import { renderCell, type CropRel, type SheetCellImage, buildSheetPdf } from '../../../lib/printrender';
import { loadSource, sheetFilename, type PrintSource } from '../../../lib/printsource';
import { paperById, parseSizeMm, labelMm } from '../../../lib/paper';

export const prerender = false;

const MAX_CELLS = 40;       // verschiedene Bilder je Bogen
const MAX_COPIES = 200;     // Exemplare je Bild
const MAX_PAGES = 20;

interface CellIn {
  id: string;
  src: PrintSource;
  crop?: CropRel | null;
  wMm?: number; hMm?: number;
  size?: string;            // Freitext („12x15", „35x45mm") als Alternative zu wMm/hMm
  count?: number;
  allowRotate?: boolean;
  landscape?: boolean;      // Bildformat quer statt hoch
}

const json = (b: unknown, s = 200) =>
  new Response(JSON.stringify(b), { status: s, headers: { 'Content-Type': 'application/json' } });

export const POST: APIRoute = async ({ request, locals }) => {
  if (!locals.user) return new Response('Unauthorized', { status: 401 });
  let body: any;
  try { body = await request.json(); } catch { return json({ error: 'Ungültige Anfrage.' }, 400); }

  try {
    const sheet = readSheet(body);
    const marksMode: MarkMode = ['none', 'corner', 'grid'].includes(body?.marks?.mode) ? body.marks.mode : 'corner';
    const dpi = clamp(Number(body?.dpi) || 300, 72, 1200);
    const wantExt: 'jpg' | 'png' = body?.ext === 'png' ? 'png' : 'jpg';

    const cellsIn: CellIn[] = Array.isArray(body?.cells) ? body.cells.slice(0, MAX_CELLS) : [];
    if (!cellsIn.length) return json({ error: 'Keine Bilder angegeben.' }, 400);

    const specs: PlaceSpec[] = [];
    const resolved: { cell: CellIn; wMm: number; hMm: number }[] = [];
    for (const [i, c] of cellsIn.entries()) {
      const size = cellSize(c);
      if (!size) return json({ error: `Bild ${i + 1}: Maß fehlt oder ist ungültig.` }, 400);
      const id = String(c.id || `c${i}`);
      specs.push({
        id, wMm: size.w, hMm: size.h,
        count: clamp(Math.round(Number(c.count) || 1), 1, MAX_COPIES),
        allowRotate: c.allowRotate !== false,
      });
      resolved.push({ cell: { ...c, id }, wMm: size.w, hMm: size.h });
    }

    const plan = layout(specs, sheet);
    if (!plan.pages.length) {
      return json({ error: 'Nichts platzierbar — Bildmaß größer als die Nutzfläche des Bogens.', unplaced: plan.unplaced }, 422);
    }
    if (plan.pages.length > MAX_PAGES) return json({ error: `Zu viele Bogen (${plan.pages.length}). Bitte Anzahl reduzieren.` }, 422);

    // Für jedes Bild genau einmal rendern — auch bei 24 Exemplaren.
    // Gedrehte Platzierungen brauchen eine eigene Fassung.
    const images: Record<string, SheetCellImage> = {};
    const needRotated = new Set<string>();
    const needPlain = new Set<string>();
    for (const pg of plan.pages) for (const p of pg.placements) (p.rotated ? needRotated : needPlain).add(p.specId);

    for (const r of resolved) {
      const buf = await loadSource(r.cell.src, locals.user as any);
      if (needPlain.has(r.cell.id)) {
        const out = await renderCell(buf, r.cell.crop ?? null, r.wMm, r.hMm, dpi,
          { ext: wantExt, bleedMm: sheet.bleedMm, rotate: false });
        images[r.cell.id] = { bytes: out.buffer, ext: out.ext };
      }
      if (needRotated.has(r.cell.id)) {
        const out = await renderCell(buf, r.cell.crop ?? null, r.wMm, r.hMm, dpi,
          { ext: wantExt, bleedMm: sheet.bleedMm, rotate: true });
        images[`${r.cell.id}::rot`] = { bytes: out.buffer, ext: out.ext };
      }
    }

    // Platzierungen auf die passende Bildfassung umbiegen.
    const pages = plan.pages.map((pg) => ({
      placements: pg.placements.map((p) => ({ ...p, specId: p.rotated ? `${p.specId}::rot` : p.specId })),
    }));

    const marks = plan.pages.map((pg) =>
      cutMarks(pg, sheet, {
        mode: marksMode,
        lengthMm: numOr(body?.marks?.lengthMm, 4, 1, 20),
        offsetMm: body?.marks?.offsetMm != null ? numOr(body.marks.offsetMm, 3, 0, 20) : undefined,
        bleedMm: sheet.bleedMm,
      }));

    const kinds = resolved.map((r) => `${labelMm(r.wMm, r.hMm)}${specs.find((s) => s.id === r.cell.id)!.count > 1 ? ` ×${specs.find((s) => s.id === r.cell.id)!.count}` : ''}`);
    const footer = body?.footer === false ? null
      : `Klarbild · ${labelMm(sheet.wMm, sheet.hMm)} · ${kinds.join(' · ')} · ${dpi} dpi · Druck bei 100 % (nicht „an Seite anpassen")`;

    const bytes = await buildSheetPdf({
      sheet, pages, marksPerPage: marks, images,
      title: String(body?.title || 'Klarbild Druckbogen'),
      footer,
      markWidthPt: numOr(body?.marks?.widthPt, 0.25, 0.1, 2),
    });

    return new Response(Buffer.from(bytes), {
      headers: {
        'Content-Type': 'application/pdf',
        'Content-Disposition': `attachment; filename="${sheetFilename(body?.name || 'druckbogen', 'pdf')}"`,
        'X-Klarbild-Pages': String(pages.length),
        'X-Klarbild-Per-Sheet': String(plan.perSheet),
      },
    });
  } catch (e: any) {
    return json({ error: e?.message || 'Druckbogen konnte nicht erzeugt werden.' }, 400);
  }
};

function readSheet(body: any): SheetSpec {
  let w: number | null = null, h: number | null = null;
  const p = body?.paper;
  if (typeof p === 'string') { const pp = paperById(p); if (pp) { w = pp.w; h = pp.h; } }
  else if (p && typeof p === 'object') {
    if (p.id) { const pp = paperById(String(p.id)); if (pp) { w = pp.w; h = pp.h; } }
    if (p.wMm && p.hMm) { w = Number(p.wMm); h = Number(p.hMm); }
    if (!w && p.size) { const s = parseSizeMm(String(p.size)); if (s) { w = s.w; h = s.h; } }
  }
  if (!w || !h) throw new Error('Papierformat fehlt oder ist unbekannt.');
  if (body?.landscape) [w, h] = [h, w];
  if (w < 20 || h < 20 || w > 2000 || h > 2000) throw new Error('Papierformat außerhalb des zulässigen Bereichs.');

  const bleedMm = numOr(body?.bleedMm, 0, 0, 10);
  const sheet: SheetSpec = {
    wMm: w, hMm: h,
    marginMm: numOr(body?.marginMm, 5, 0, 50),
    gapMm: numOr(body?.gapMm, 4, 0, 100),
    bleedMm,
    center: body?.center !== false,
  };
  sheet.gapMm = effectiveGap(sheet);
  return sheet;
}

function cellSize(c: CellIn): { w: number; h: number } | null {
  let s: { w: number; h: number } | null = null;
  if (Number(c.wMm) > 0 && Number(c.hMm) > 0) s = { w: Number(c.wMm), h: Number(c.hMm) };
  else if (c.size) s = parseSizeMm(String(c.size));
  if (!s || s.w < 5 || s.h < 5 || s.w > 2000 || s.h > 2000) return null;
  return c.landscape ? { w: s.h, h: s.w } : s;
}

const clamp = (n: number, lo: number, hi: number) => Math.min(hi, Math.max(lo, n));
const numOr = (v: any, def: number, lo: number, hi: number) => {
  const n = Number(v);
  return Number.isFinite(n) ? clamp(n, lo, hi) : def;
};