import { Hono } from 'hono';
import { serve } from 'bun';
import Parser from 'rss-parser';
import { Feed, type Item } from 'feed';

const app = new Hono();
const parser = new Parser();

app.get('/group-by-day', async (c) => {
  const feedUrl = c.req.query('feedUrl');
  if (!feedUrl) {
    return c.text('Missing feedUrl query parameter', 400);
  }
  try {
    const { title, feedUrl: feedId, link: feedLink, items } = await parser.parseURL(feedUrl);

    const grouped = items.reduce((acc, { pubDate, content, contentSnippet, summary, link }) => {
      const day = new Date(pubDate as string).toISOString().slice(0, 10);
      acc[day] = acc[day] || [];
      acc[day].push({
        link,
        content: content || contentSnippet || summary || ''
      });
      return acc;
    }, {});

    const days = Object.keys(grouped).sort().reverse();
    const today = new Date();
    today.setHours(0, 0, 0, 0);

    const feedItems: Item[] = days.map(day => {
      const dateStr = new Date(day).toLocaleDateString('en-US', {
        year: 'numeric',
        month: 'long',
        day: 'numeric'
      });
      return {
        title: `${title} - ${dateStr}`,
        id: day,
        date: new Date(day),
        link: grouped[day][0].link,
        content: grouped[day].map((p: any) => p.content).join('\n\n---------------------\n\n')
      };
    }).filter(p => p.date < today);

    const outFeed = new Feed({ 
        title: title as string, 
        id: feedId as string, 
        link: feedLink,
        copyright: ''
    });

    for (const item of feedItems) {
        outFeed.addItem(item)
    }

    const xml = outFeed.rss2();

    return c.text(xml, 200, {
        'Content-Type': 'text/xml',
      });
  } catch (err: any) {
    return c.text(`Error fetching or processing feed: ${err.message}`, 500);
  }
});

// Start Bun server on port 3000
serve({
  fetch: app.fetch,
  port: 3000
});