import type { Actions, PageServerLoad } from './$types';
import { fail } from '@sveltejs/kit';
import { writeFileSync, mkdirSync, existsSync, unlinkSync } from 'node:fs';
import { join } from 'node:path';
import { randomUUID } from 'node:crypto';
import { getContent, resetImage, setImage } from '$lib/server/content';
import { DEFAULT_IMAGES } from '$lib/content/defaults';

const UPLOAD_DIR = join(process.cwd(), 'static', 'img', 'uploads');
const MAX_BYTES = 8 * 1024 * 1024; // 8 MB
const ALLOWED = new Set(['image/png', 'image/jpeg', 'image/webp', 'image/gif', 'image/svg+xml']);
const LOCKED_SLOTS = new Set(['cima_logo']);

export const load: PageServerLoad = () => {
  const content = getContent();
  const images: typeof content.images = {};
  for (const [id, img] of Object.entries(content.images)) {
    if (LOCKED_SLOTS.has(id)) continue;
    images[id] = img;
  }
  return { images };
};

function extFromType(type: string, fallbackName: string): string {
  if (type === 'image/png') return 'png';
  if (type === 'image/jpeg') return 'jpg';
  if (type === 'image/webp') return 'webp';
  if (type === 'image/gif') return 'gif';
  if (type === 'image/svg+xml') return 'svg';
  const m = /\.([a-zA-Z0-9]+)$/.exec(fallbackName);
  return m ? m[1].toLowerCase() : 'bin';
}

export const actions: Actions = {
  upload: async ({ request }) => {
    if (!existsSync(UPLOAD_DIR)) mkdirSync(UPLOAD_DIR, { recursive: true });
    const form = await request.formData();
    const slot = String(form.get('slot') ?? '');
    const alt = String(form.get('alt') ?? '').trim();
    const file = form.get('file');

    if (!slot || !(slot in DEFAULT_IMAGES) || LOCKED_SLOTS.has(slot)) return fail(400, { error: 'Slot immagine non valido.' });
    if (!(file instanceof File) || !file.size) {
      // alt-only update
      if (alt) {
        setImage(slot, { alt });
        return { success: true, slot, altOnly: true };
      }
      return fail(400, { error: 'Nessun file caricato.' });
    }
    if (file.size > MAX_BYTES) return fail(400, { error: 'File troppo grande (max 8 MB).' });
    if (file.type && !ALLOWED.has(file.type)) return fail(400, { error: `Tipo file non supportato: ${file.type}.` });

    const buf = Buffer.from(await file.arrayBuffer());
    const ext = extFromType(file.type, file.name);
    const filename = `${slot}-${randomUUID().slice(0, 8)}.${ext}`;
    const fullPath = join(UPLOAD_DIR, filename);
    writeFileSync(fullPath, buf);

    const publicPath = `/img/uploads/${filename}`;
    const next = setImage(slot, { src: publicPath, alt: alt || undefined });
    return { success: true, slot, src: next.src };
  },

  reset: async ({ request }) => {
    const form = await request.formData();
    const slot = String(form.get('slot') ?? '');
    if (!slot || !(slot in DEFAULT_IMAGES) || LOCKED_SLOTS.has(slot)) return fail(400, { error: 'Slot non valido.' });

    const current = getContent().images[slot];
    if (current?.src?.startsWith('/img/uploads/')) {
      const fullPath = join(process.cwd(), 'static', current.src);
      try {
        if (existsSync(fullPath)) unlinkSync(fullPath);
      } catch {
        // ignore
      }
    }
    resetImage(slot);
    return { success: true, slot, reset: true };
  }
};