import type { FastifyPluginAsync, FastifyRequest } from 'fastify';
import { z } from 'zod';
import { prisma } from '../db.js';
import { checkRateLimit, rateLimitResponse } from '../lib/rate-limit.js';

function stripHtmlToMarkdown(html: string): string {
  if (!html) return '';
  return html
    .replace(/<h[1-6][^>]*>(.*?)<\/h[1-6]>/gi, '\n## $1\n')
    .replace(/<p[^>]*>(.*?)<\/p>/gi, '\n$1\n')
    .replace(/<a[^>]*href="([^"]+)"[^>]*>(.*?)<\/a>/gi, '[$2]($1)')
    .replace(/<strong[^>]*>(.*?)<\/strong>/gi, '**$1**')
    .replace(/<em[^>]*>(.*?)<\/em>/gi, '*$1*')
    .replace(/<[^>]+>/g, '')
    .replace(/\n\s*\n/g, '\n\n')
    .trim();
}

export const ragRoutes: FastifyPluginAsync = async (app) => {
  app.get('/api/v1/rag/:slug', async (req, reply) => {
    const { slug } = req.params as { slug: string };
    const article = await prisma.article.findUnique({
      where: { slug },
      select: { title: true, summary: true, content: true, dateModified: true }
    });

    if (!article) return reply.code(404).send('# Not Found');

    reply.header('Content-Type', 'text/markdown; charset=utf-8');
    
    let markdown = `# ${article.title}\n\n`;
    if (article.summary) markdown += `> ${article.summary}\n\n`;
    markdown += `Last Modified: ${article.dateModified?.toISOString()}\n\n`;
    markdown += stripHtmlToMarkdown(article.content);

    return markdown;
  });

  app.post('/api/v1/search/semantic', async (req: FastifyRequest, reply) => {
    const rl = await checkRateLimit(req.ip, 'semantic', 10, 60);
    if (rl.limited) return rateLimitResponse(reply, rl.retryAfter);

    const schema = z.object({ query: z.string().min(1), limit: z.number().max(20).optional() });
    const parsed = schema.safeParse(req.body);
    if (!parsed.success) return reply.code(400).send({ error: 'invalid_input' });

    const { semanticSearch } = await import('../lib/embeddings.js');
    const results = await semanticSearch(parsed.data.query, parsed.data.limit || 5);
    return { results };
  });
};