'use strict';

/**
 * /api/preferences (Session 49) — per-user onboarding preferences.
 *
 * Stored in Supabase auth `user_metadata.preferences` (NO migration / extra
 * table). Auth-gated by the shared `requireAuth` (req.user = the app `users`
 * row; req.user.id is the auth user id). Reads/writes via the service client's
 * admin API. POST is a PARTIAL merge — only the keys present in the body change.
 *
 * Shape: { sports: string[], books: string[], weekly_limit: number|null,
 *          onboarding_complete: boolean }
 */

const express = require('express');
const { requireAuth } = require('../middleware/auth');
const { getSupabaseServiceClient } = require('../utils/supabase');

const router = express.Router();
router.use(requireAuth);

const DEFAULTS = { sports: [], books: [], weekly_limit: null, onboarding_complete: false };
const VALID_SPORTS = new Set(['mlb', 'nba', 'wnba', 'soccer']);

/** Keep only valid keys/values; only present keys are returned (partial). */
function sanitizePrefs(p = {}) {
  const out = {};
  if (Array.isArray(p.sports)) {
    out.sports = [...new Set(p.sports.map((s) => String(s).toLowerCase()).filter((s) => VALID_SPORTS.has(s)))];
  }
  if (Array.isArray(p.books)) {
    out.books = [...new Set(p.books.map((b) => String(b).slice(0, 40)))].slice(0, 12);
  }
  if (Object.prototype.hasOwnProperty.call(p, 'weekly_limit')) {
    const n = Number(p.weekly_limit);
    out.weekly_limit = p.weekly_limit === null ? null : Number.isFinite(n) ? Math.max(0, Math.min(100000, n)) : null;
  }
  if (typeof p.onboarding_complete === 'boolean') out.onboarding_complete = p.onboarding_complete;
  return out;
}

async function readPrefs(sb, userId) {
  const { data, error } = await sb.auth.admin.getUserById(userId);
  if (error) throw error;
  const prefs = (data && data.user && data.user.user_metadata && data.user.user_metadata.preferences) || {};
  const meta = (data && data.user && data.user.user_metadata) || {};
  return { prefs: { ...DEFAULTS, ...prefs }, meta };
}

// GET /api/preferences
router.get('/', async (req, res) => {
  try {
    const sb = getSupabaseServiceClient();
    const { prefs } = await readPrefs(sb, req.user.id);
    return res.json(prefs);
  } catch (err) {
    console.error('[preferences/get]', err.message);
    return res.status(503).json({ error: 'Could not load preferences' });
  }
});

// POST /api/preferences — partial merge.
router.post('/', async (req, res) => {
  try {
    const sb = getSupabaseServiceClient();
    const { prefs: existing, meta } = await readPrefs(sb, req.user.id);
    const merged = { ...existing, ...sanitizePrefs(req.body || {}) };
    const { error } = await sb.auth.admin.updateUserById(req.user.id, {
      user_metadata: { ...meta, preferences: merged },
    });
    if (error) throw error;
    return res.json({ ok: true, preferences: merged });
  } catch (err) {
    console.error('[preferences/post]', err.message);
    return res.status(503).json({ error: 'Could not save preferences' });
  }
});

module.exports = router;