import { NextRequest, NextResponse } from 'next/server';
import { hybridAI } from '@/lib/ai/hybridRouter';
import {
  getLegacyArticlesBySection,
  getLegacyArticleBySlug,
} from '@/lib/articles/legacy-source';

export async function POST(request: NextRequest) {
  try {
    const { interests, readingHistory } = await request.json();

    // Pull a recent slice of news for the AI to choose from. Cap at 100 so the
    // prompt stays bounded.
    const news = await getLegacyArticlesBySection('news', 100);

    const articleIndex = news.map((a) => ({
      slug: a.slug,
      title: a.title,
      excerpt: a.excerpt,
      tags: a.tags,
      category: a.category,
      date: a.date,
    }));

    const systemPrompt = `You are a personalized content recommendation engine for AV Beat, a pro AV / live production / display tech news platform.
Given a reader's topic interests and reading history, select the 4 most relevant articles from the provided article list.
Return ONLY a valid JSON array of slugs in order of relevance. Example: ["slug-1","slug-2","slug-3","slug-4"]
Do not include any explanation or markdown — only the raw JSON array.`;

    const userPrompt = `Reader interests: ${interests?.length ? interests.join(', ') : 'general pro AV and live production'}
Reading history (recently read slugs): ${readingHistory?.length ? readingHistory.join(', ') : 'none'}

Available articles:
${JSON.stringify(articleIndex, null, 2)}

Return the 4 most relevant article slugs as a JSON array.`;

    const result = await hybridAI(
      [
        { role: 'system', content: systemPrompt },
        { role: 'user', content: userPrompt },
      ],
      { maxTokens: 200, temperature: 0.3, priority: 4 }
    );

    const content = result.text;

    let slugs: string[] = [];
    try {
      const match = content.match(/\[[\s\S]*?\]/);
      slugs = match ? JSON.parse(match[0]) : JSON.parse(content.trim());
    } catch {
      const matches = content.match(/"([^"]+)"/g);
      slugs = matches ? matches.map((m: string) => m.replace(/"/g, '')).slice(0, 4) : [];
    }

    // Resolve from the candidate set first; if a slug wasn't in the recent
    // window, look it up via DB so AI hallucinations or older slugs still resolve.
    const suggested = (
      await Promise.all(
        slugs.slice(0, 4).map(async (slug: string) =>
          news.find((a) => a.slug === slug) || (await getLegacyArticleBySlug(slug))
        )
      )
    ).filter(Boolean);

    if (suggested.length === 0) {
      return NextResponse.json({ suggestions: news.slice(0, 4) });
    }

    return NextResponse.json({ suggestions: suggested });
  } catch (error) {
    console.error('Article suggestions error:', error);
    const fallback = await getLegacyArticlesBySection('news', 4);
    return NextResponse.json({ suggestions: fallback });
  }
}