const express = require('express');
const router = express.Router();
const contentService = require('../services/content');

function renderBlogListing(req, res, filterType, filterVal) {
  let posts = contentService.getAllPosts();
  const category = filterType === 'category' ? filterVal : req.query.category;
  const tag = filterType === 'tag' ? filterVal : req.query.tag;
  const page = req.query.page;

  let activeFilter = null;

  if (category) {
    const catLower = category.trim().toLowerCase();
    posts = posts.filter(p => (p.category || '').toLowerCase() === catLower);
    activeFilter = { type: 'category', value: category };
  } else if (tag) {
    const tagLower = tag.trim().toLowerCase();
    posts = posts.filter(p => (p.tags || []).some(t => t.toLowerCase() === tagLower));
    activeFilter = { type: 'tag', value: tag };
  }

  const postsPerPage = 12;
  const currentPage = Math.max(1, parseInt(page, 10) || 1);
  const totalPosts = posts.length;
  const totalPages = Math.ceil(totalPosts / postsPerPage);

  const startIndex = (currentPage - 1) * postsPerPage;
  const paginatedPosts = posts.slice(startIndex, startIndex + postsPerPage);

  const taxonomy = contentService.getTaxonomy();

  res.render('pages/blogs', {
    title: activeFilter ? `${activeFilter.value} - ${activeFilter.type === 'category' ? 'Category' : 'Tag'} - ${res.locals.site.title}` : `Blogs - ${res.locals.site.title}`,
    posts: paginatedPosts,
    currentPage,
    totalPages,
    totalPosts,
    activeFilter,
    taxonomy
  });
}

router.get('/blogs', (req, res) => renderBlogListing(req, res));
router.get('/category/:category', (req, res) => renderBlogListing(req, res, 'category', req.params.category));
router.get('/tag/:tag', (req, res) => renderBlogListing(req, res, 'tag', req.params.tag));
router.get('/tags/:tag', (req, res) => renderBlogListing(req, res, 'tag', req.params.tag));

module.exports = router;