import { NextResponse } from 'next/server';
import { revalidatePath } from 'next/cache';
import { setSection, resetSection } from '@/lib/db/store';
import {
  POSTS_KEY,
  loadPost,
  loadPostOverrides,
  isKnownSlug,
} from '@/lib/content/posts-store';
import type { PostContent } from '@/lib/content/posts';

export const runtime = 'nodejs';

const ACCENTS = ['electric', 'violet', 'magenta', 'emerald', 'cyan'];

/** Minimal structural validation for an incoming PostContent payload. */
function validPost(data: unknown): data is {
  date: string;
  accent: string;
  en: { lead: string; blocks: unknown[] };
  fa: { lead: string; blocks: unknown[] };
} {
  if (!data || typeof data !== 'object') return false;
  const d = data as Record<string, unknown>;
  if (typeof d.date !== 'string') return false;
  if (typeof d.accent !== 'string' || !ACCENTS.includes(d.accent)) return false;
  for (const loc of ['en', 'fa'] as const) {
    const art = d[loc] as Record<string, unknown> | undefined;
    if (!art || typeof art !== 'object') return false;
    if (typeof art.lead !== 'string') return false;
    if (!Array.isArray(art.blocks)) return false;
  }
  return true;
}

// GET ?slug=rag-eval-framework -> live (merged) article + override flag
export async function GET(req: Request) {
  const slug = new URL(req.url).searchParams.get('slug') ?? '';
  if (!isKnownSlug(slug)) {
    return NextResponse.json({ error: 'unknown post' }, { status: 400 });
  }
  return NextResponse.json({
    slug,
    post: loadPost(slug),
    overridden: slug in loadPostOverrides(),
  });
}

// POST { slug, data: PostContent } -> save the article override
export async function POST(req: Request) {
  let body: { slug?: string; data?: unknown };
  try {
    body = await req.json();
  } catch {
    return NextResponse.json({ error: 'bad json' }, { status: 400 });
  }

  const slug = body.slug ?? '';
  if (!isKnownSlug(slug)) {
    return NextResponse.json({ error: 'unknown post' }, { status: 400 });
  }
  if (!validPost(body.data)) {
    return NextResponse.json(
      { error: 'expected a { date, accent, en:{lead,blocks}, fa:{lead,blocks} } payload' },
      { status: 400 },
    );
  }

  const overrides = loadPostOverrides();
  // validPost has confirmed the shape (incl. accent ∈ ACCENTS) above.
  overrides[slug] = body.data as unknown as PostContent;
  setSection(POSTS_KEY, overrides);

  revalidatePath(`/blog/${slug}`);
  revalidatePath('/', 'layout');
  return NextResponse.json({ ok: true });
}

// DELETE ?slug=… -> revert one article to its in-code default
export async function DELETE(req: Request) {
  const slug = new URL(req.url).searchParams.get('slug') ?? '';
  if (!isKnownSlug(slug)) {
    return NextResponse.json({ error: 'unknown post' }, { status: 400 });
  }

  const overrides = loadPostOverrides();
  delete overrides[slug];
  if (Object.keys(overrides).length === 0) {
    resetSection(POSTS_KEY);
  } else {
    setSection(POSTS_KEY, overrides);
  }

  revalidatePath(`/blog/${slug}`);
  revalidatePath('/', 'layout');
  return NextResponse.json({ ok: true });
}