import { NextResponse } from 'next/server';
import { withAdmin } from '@/lib/admin/withAdmin';
import { revalidatePath } from 'next/cache';
import { readGalleryYaml, writeGalleryYaml } from '@/lib/admin/yaml-service';
import { invalidateConfigCache, deriveGallery } from '@/lib/config';
import { immich } from '@/lib/immich';
import type { GalleryYaml } from '@/lib/config/schema';
import { hashPasswordKeys } from '@/lib/admin/passwordHashing';

const PASSWORD_KEY = new Set(['password']);

/** GET: Read current gallery.yaml config. */
export const GET = withAdmin(async () => {
  const gallery = await readGalleryYaml();
  return NextResponse.json({ gallery: gallery || { hero: [], albums: [], subpages: [] } });
});

/** PUT: Write gallery.yaml config. */
export const PUT = withAdmin(async (request: Request) => {
  const body = await request.json().catch(() => null);
  if (!body?.gallery) {
    return NextResponse.json({ error: 'Missing gallery data' }, { status: 400 });
  }

  // Validate basic structure
  const gallery = body.gallery as GalleryYaml;
  if (!Array.isArray(gallery.hero) && typeof gallery.hero !== 'string' && gallery.hero != null) {
    return NextResponse.json({ error: 'Invalid hero format' }, { status: 400 });
  }

  // Run the *real* derivation before writing. getConfig() throws on a gallery
  // with no albums and no subpages, a subpage with no name, or a subpage with
  // neither albums nor sections — all of which the page builder can produce.
  // Writing one used to report "Saved successfully" and then take the public
  // site down until someone noticed.
  //
  // Calling deriveGallery rather than re-checking those conditions here is
  // deliberate: a second copy of the rules would drift from the first. So is
  // validating before the write rather than rolling back after — a rollback
  // leaves a window in which other requests read the broken config.
  try {
    deriveGallery(gallery);
  } catch (err) {
    const reason = err instanceof Error ? err.message : 'Invalid gallery structure';
    console.warn('[Admin] Rejected an unloadable gallery.yaml:', reason);
    return NextResponse.json({ error: reason }, { status: 400 });
  }

  try {
    // Subpage and album passwords, wherever the entry sits (#690).
    const toWrite = await hashPasswordKeys(
      gallery,
      PASSWORD_KEY,
      await readGalleryYaml().catch(() => null),
    );
    await writeGalleryYaml(toWrite);
    invalidateConfigCache();
    immich.invalidateAll();
    // Revalidate all pages so the homepage picks up new hero images immediately
    revalidatePath('/', 'layout');
    revalidatePath('/[...path]', 'page');
    return NextResponse.json({
      success: true,
      message: 'Saved successfully. Backup of previous version created.',
      // What was written, passwords hashed, so the editor can take it over.
      gallery: toWrite,
    });
  } catch (err) {
    console.error('[Admin] Failed to write gallery.yaml:', err);
    return NextResponse.json({ error: 'Failed to save gallery config' }, { status: 500 });
  }
});