const express = require('express');
const fs = require('fs');
const path = require('path');

const router = express.Router();

const FEATURES_DIR = path.join(__dirname, '..', '..', 'frontend', 'components');

/* =========================
   GET /api/features/list

   Walks frontend/components/<id>/ and returns one entry per directory that
   contains a feature.json — the WebUI's page manifest, discovered from the
   folders themselves (exactly how /api/themes/list discovers themes). Drop a
   components/<id>/ folder in and its page appears; delete it and the page is
   gone — no central edit. The navigation kernel fetches this and falls back to
   the checked-in components/manifest.dev.json if the API is unavailable.

   Each feature.json declares: id, routes[], optional module (self-registering
   index.js), optional handler (legacy fallback method), navId, nav{}, and order
   (controls list + route-precedence ordering — e.g. apps before app-detail so
   the '/apps*' wildcard wins over '/app*').

   Public — the page list isn't sensitive and the kernel needs it before login
   to render the right route (same rationale as the themes list).
========================= */
router.get('/list', (req, res) => {
  const features = [];
  try {
    if (fs.existsSync(FEATURES_DIR)) {
      for (const entry of fs.readdirSync(FEATURES_DIR, { withFileTypes: true })) {
        if (!entry.isDirectory()) continue;
        const metaPath = path.join(FEATURES_DIR, entry.name, 'feature.json');
        if (!fs.existsSync(metaPath)) continue;
        try {
          const meta = JSON.parse(fs.readFileSync(metaPath, 'utf8'));
          if (meta && meta.id && Array.isArray(meta.routes)) {
            features.push(meta);
          } else {
            console.warn(`[features] ${entry.name}/feature.json missing id/routes — skipped`);
          }
        } catch (e) {
          console.warn(`[features] ${entry.name}/feature.json is malformed — skipped:`, e.message);
        }
      }
    }
  } catch (err) {
    console.error('Error scanning features directory:', err);
  }

  // Ascending `order` controls both nav order and route-registration order
  // (the latter preserves wildcard precedence). Missing order sorts last.
  features.sort((a, b) => ((a.order ?? 999) - (b.order ?? 999)));

  res.json({ version: 1, source: 'scan', features });
});

module.exports = router;