// ==UserScript==
// @name         SAS bonus watch
// @namespace    sas-bonus-finder
// @version      1.1.1
// @description  Watches SAS EuroBonus award seats from your own browser and alerts you when matching seats appear.
// @author       Måns Sivertsson
// @homepageURL  https://gitea.mscloud.site/mans/sas-bonus-watch
// @supportURL   https://gitea.mscloud.site/mans/sas-bonus-watch/issues
// @updateURL    https://gitea.mscloud.site/mans/sas-bonus-watch/raw/branch/main/sas-bonus-watch.user.js
// @downloadURL  https://gitea.mscloud.site/mans/sas-bonus-watch/raw/branch/main/sas-bonus-watch.user.js
// @match        https://www.sas.se/robots.txt*
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_xmlhttpRequest
// @grant        GM_notification
// @connect      ntfy.sh
// @connect      discord.com
// @connect      hooks.slack.com
// @connect      *
// @run-at       document-idle
// @noframes
// ==/UserScript==

/*
 * Open https://www.sas.se/robots.txt in a tab and leave it open (pinning it helps).
 * The tab turns into a dashboard where you edit the config and see matches.
 *
 * Requests go to sas.se from this tab, at most one every `min_request_interval`
 * seconds (+ jitter), and a full sweep at most every `cycle_interval` seconds.
 *   1. calendar  /bff/award-finder/destinations/v1  one request per route pair,
 *      returns every date with seats in both directions
 *   2. details   /bff/award-finder/routes/v1        only for dates in your ranges
 *      whose calendar entry changed (or every `detail_max_age` seconds)
 */

(function () {
  'use strict';

  const CABINS = { AG: 'SAS Go', AP: 'SAS Plus', AB: 'SAS Business' };

  const DEFAULT_CONFIG = {
    settings: {
      market: 'se-sv',
      min_request_interval: 40,
      jitter: 20,
      cycle_interval: 900,
      detail_max_age: 21600,
      prefilter: true,
      desktop_notifications: true,
    },
    notify: [
      { type: 'ntfy', url: 'https://ntfy.sh/CHANGE-ME-to-a-long-random-topic', priority: 'high' },
    ],
    watches: [
      {
        name: 'Tokyo over Christmas',
        enabled: true,
        origins: ['ARN', 'CPH'],
        destinations: ['HND', 'NRT'],
        from: '2026-12-15',
        to: '2027-01-10',
        cabins: ['AP', 'AB'],
        min_seats: 2,
        max_stops: 1,
        require_both_legs: true,
        min_nights: 10,
        max_nights: 21,
      },
    ],
  };

  // ---------------------------------------------------------------- dates

  const DAY = 86400000;
  const isoDate = (d) => d.toLocaleDateString('sv-SE'); // YYYY-MM-DD in local time
  const todayISO = () => isoDate(new Date());
  const addDays = (iso, n) => new Date(Date.parse(iso + 'T00:00:00Z') + n * DAY).toISOString().slice(0, 10);
  const daysBetween = (a, b) => Math.round((Date.parse(b) - Date.parse(a)) / DAY);
  const fmtDay = (iso) => new Date(iso + 'T00:00:00Z').toLocaleDateString('en-GB',
    { weekday: 'short', day: '2-digit', month: 'short', timeZone: 'UTC' });

  function dayList(range, notBefore) {
    const out = [];
    for (let d = range.from < notBefore ? notBefore : range.from; d <= range.to; d = addDays(d, 1)) out.push(d);
    return out;
  }

  // ---------------------------------------------------------------- config

  const blank = (v) => v == null || v === '';

  /** Old configs had separate outbound/inbound ranges; fold them into one travel window. */
  function migrateWatch(w) {
    if (!w || w.from || !w.outbound) return w;
    const { outbound, inbound, ...rest } = w;
    return { ...rest, from: outbound.from, to: (inbound || outbound).to,
      require_both_legs: w.require_both_legs ?? Boolean(inbound) };
  }

  const WATCH_KEYS = ['name', 'enabled', 'origins', 'destinations', 'from', 'to', 'cabins', 'min_seats', 'max_stops',
    'require_both_legs', 'min_nights', 'max_nights'];

  /** Returns a normalized config with only the enabled watches; throws with every problem found. */
  function validateConfig(raw) {
    const errors = [];
    const err = (m) => errors.push(m);
    const s = { ...DEFAULT_CONFIG.settings, ...(raw.settings || {}) };
    for (const k of Object.keys(raw.settings || {})) if (!(k in DEFAULT_CONFIG.settings)) err(`settings: unknown key "${k}"`);
    for (const k of ['min_request_interval', 'jitter', 'cycle_interval', 'detail_max_age']) s[k] = Number(s[k]);
    if (!(s.min_request_interval >= 20)) err('settings: request interval must be at least 20 seconds');
    if (!(s.cycle_interval >= 60)) err('settings: sweep interval must be at least 60 seconds');

    const dateOk = (v) => /^\d{4}-\d{2}-\d{2}$/.test(v) && !isNaN(Date.parse(v));
    const airports = (v, where) => {
      const list = (Array.isArray(v) ? v : String(v ?? '').split(/[\s,;/]+/)).map((c) => String(c).trim().toUpperCase()).filter(Boolean);
      if (!list.length) err(`${where}: at least one airport code is required`);
      list.filter((c) => !/^[A-Z]{3}$/.test(c)).forEach((c) => err(`${where}: "${c}" is not a 3-letter airport code`));
      return list;
    };
    const int = (v, where, min) => {
      if (blank(v)) return null;
      const n = Number(v);
      if (!Number.isInteger(n) || n < min) err(`${where} must be a whole number ≥ ${min}`);
      return n;
    };

    const all = (raw.watches || []).map(migrateWatch).map((w, i) => {
      const name = String(w.name || '').trim() || `watch ${i + 1}`;
      const at = `"${name}"`;
      Object.keys(w).filter((k) => !WATCH_KEYS.includes(k)).forEach((k) => err(`${at}: unknown key "${k}"`));
      const cabins = (w.cabins || Object.keys(CABINS)).map((c) => String(c).toUpperCase());
      if (!cabins.length) err(`${at}: pick at least one cabin`);
      cabins.filter((c) => !CABINS[c]).forEach((c) => err(`${at}: unknown cabin "${c}", use AG, AP or AB`));
      if (!dateOk(w.from) || !dateOk(w.to)) err(`${at}: "from" and "to" must be dates (YYYY-MM-DD)`);
      else if (w.to < w.from) err(`${at}: "to" is before "from"`);
      const window = { from: w.from, to: w.to };
      const min_nights = int(w.min_nights, `${at}: min nights`, 0);
      const max_nights = int(w.max_nights, `${at}: max nights`, 0);
      if (min_nights != null && max_nights != null && max_nights < min_nights) err(`${at}: max nights is below min nights`);
      return {
        name,
        enabled: w.enabled !== false,
        origins: airports(w.origins, `${at}: origins`),
        destinations: airports(w.destinations, `${at}: destinations`),
        window,
        outbound: window,
        inbound: window,
        cabins,
        min_seats: int(w.min_seats, `${at}: seats`, 1) ?? 1,
        max_stops: int(w.max_stops, `${at}: max stops`, 0),
        require_both_legs: w.require_both_legs !== false || min_nights != null || max_nights != null,
        min_nights,
        max_nights,
      };
    });
    if (new Set(all.map((w) => w.name)).size !== all.length) err('watch names must be unique');

    const notify = (raw.notify || []).filter(Boolean).map((n, i) => {
      const type = String(n.type || '').toLowerCase();
      if (!['ntfy', 'discord', 'slack', 'webhook'].includes(type)) err(`notification ${i + 1}: unknown type "${n.type}"`);
      if (!/^https?:\/\//.test(n.url || '')) err(`notification ${i + 1}: URL must start with http(s)://`);
      return { type, url: n.url, priority: n.priority };
    });

    if (errors.length) throw new Error(errors.join('\n'));
    return { settings: s, notify, watches: all.filter((w) => w.enabled) };
  }

  // ---------------------------------------------------------------- SAS API parsing

  const seatsOf = (raw) => ({ AG: +raw?.AG || 0, AP: +raw?.AP || 0, AB: +raw?.AB || 0 });

  function parseCalendar(data, destination) {
    const entry = (data || []).find((d) => d.airportCode === destination) || (data || [])[0] || {};
    const toMap = (items) => Object.fromEntries((items || []).map((i) => [i.date, seatsOf(i)]));
    return { outbound: toMap(entry.availability?.outbound), inbound: toMap(entry.availability?.inbound) };
  }

  const parseFlight = (f) => ({
    flight_id: f.flightId,
    departure_date: f.departureDate,
    departure_time: f.departureTime || '',
    arrival_date: f.arrivalDate || f.departureDate,
    arrival_time: f.arrivalTime || '',
    seats: seatsOf(f.availability),
    stops: Math.max(0, (+f.noOfFlights || 1) - 1),
    total_minutes: +f.totalTime || 0,
  });

  // ---------------------------------------------------------------- matching

  const isDirect = (w) => w.max_stops === 0;
  const legKey = (o, d, direct) => `${o}-${d}-${direct ? 1 : 0}`;
  const calKey = (o, d, direct, pax) => `${legKey(o, d, direct)}-${pax}`;
  const sig = (seats) => JSON.stringify(seats);
  const wanted = (w, seats) => w.cabins.some((c) => (seats[c] || 0) >= w.min_seats);

  function legNeeds(w) {
    const pairs = w.origins.flatMap((o) => w.destinations.filter((d) => d !== o).map((d) => [o, d]));
    const needs = pairs.map(([o, d]) => ({ watch: w, leg: 'outbound', origin: o, destination: d, dates: w.outbound }));
    if (w.inbound) needs.push(...pairs.map(([o, d]) => ({ watch: w, leg: 'inbound', origin: d, destination: o, dates: w.inbound })));
    return needs;
  }

  /** "OUT ARN→HND Mon 07 Dec 07:00→Tue 08 Dec 07:55, 1 stop (SK1417)" – everything except the seats */
  function describeFlight(m) {
    const f = m.flight;
    const arr = f.arrival_date === f.departure_date ? f.arrival_time : `${fmtDay(f.arrival_date)} ${f.arrival_time}`;
    const stops = f.stops === 0 ? 'direct' : `${f.stops} stop${f.stops > 1 ? 's' : ''}`;
    return `${m.leg === 'outbound' ? 'OUT' : 'RET'} ${m.origin}→${m.destination} ${fmtDay(f.departure_date)} ` +
      `${f.departure_time}→${arr}, ${stops} (${f.flight_id.split('-')[0]})`;
  }
  const seatText = (cabin, n) => `${CABINS[cabin]} ×${n}`;

  function matchFlights(need, flights) {
    const w = need.watch;
    const out = [];
    for (const f of flights) {
      if (f.departure_date < need.dates.from || f.departure_date > need.dates.to) continue;
      if (w.max_stops != null && f.stops > w.max_stops) continue;
      for (const c of w.cabins) {
        if ((f.seats[c] || 0) < w.min_seats) continue;
        const m = { key: `${need.leg}|${f.flight_id}|${c}`, leg: need.leg, origin: need.origin,
          destination: need.destination, flight: f, cabin: c, seats: f.seats[c] };
        m.desc = describeFlight(m);
        m.line = `${m.desc}, ${seatText(c, m.seats)}`;
        out.push(m);
      }
    }
    return out;
  }

  function applyRoundTrip(w, matches) {
    if (!w.require_both_legs) return matches;
    const outs = matches.filter((m) => m.leg === 'outbound');
    const ins = matches.filter((m) => m.leg === 'inbound');
    const ok = (o, i) => {
      const nights = daysBetween(o.flight.departure_date, i.flight.departure_date);
      return i.flight.departure_date >= o.flight.arrival_date &&
        (w.min_nights == null || nights >= w.min_nights) &&
        (w.max_nights == null || nights <= w.max_nights);
    };
    return [...outs.filter((o) => ins.some((i) => ok(o, i))), ...ins.filter((i) => outs.some((o) => ok(o, i)))];
  }

  // ---------------------------------------------------------------- watcher

  /**
   * api:    { calendar(o, d, direct, pax), flights(o, d, day, direct) }  (both may throw Blocked)
   * state:  plain object, persisted by save()
   * notify: async (title, body, data) => bool
   */
  function createWatcher({ cfg, api, state, save, notify, log, now = Date.now }) {
    state.calendar ||= {};
    state.flights ||= {};
    state.matches ||= {};
    state.events ||= [];

    // kinds: new | back | up | down | gone | unpaired
    function event(watch, kind, line) {
      state.events.unshift({ ts: new Date(now()).toISOString(), watch, kind, line });
      state.events.length = Math.min(state.events.length, 300);
    }

    function prune(today) {
      for (const k of Object.keys(state.flights)) if (k.split('|')[1] < today) delete state.flights[k];
      const names = new Set(cfg.watches.map((w) => w.name));
      for (const k of Object.keys(state.matches)) if (!names.has(k)) delete state.matches[k];
      // keep lost matches visible for two weeks (or until departure), then forget them
      const cutoff = new Date(now() - 14 * DAY).toISOString();
      for (const entries of Object.values(state.matches)) {
        for (const [k, e] of Object.entries(entries)) {
          if (e.date < today || (e.status && e.status !== 'active' && e.since < cutoff)) delete entries[k];
        }
      }
    }

    function estimate() {
      const today = todayISO();
      const cal = new Set();
      let days = 0;
      for (const w of cfg.watches) {
        for (const n of legNeeds(w)) {
          cal.add([[n.origin, n.destination].sort().join('-'), isDirect(w), w.min_seats].join('|'));
          days += dayList(n.dates, today).length;
        }
      }
      return cfg.settings.prefilter
        ? `${cal.size} calendar request(s) per sweep + detail requests for changed dates (worst case ${days})`
        : `${days} detail request(s) per sweep (prefilter off)`;
    }

    async function runCycle(notifyOn = true) {
      const s = cfg.settings;
      const today = todayISO();
      prune(today);
      const needs = cfg.watches.flatMap(legNeeds);

      // 1. calendars: one request covers both directions; passengers=N only counts flights with N seats
      const calendars = {};
      if (s.prefilter) {
        for (const n of needs) {
          const direct = isDirect(n.watch), pax = n.watch.min_seats;
          if (calendars[calKey(n.origin, n.destination, direct, pax)]) continue;
          const c = await api.calendar(n.origin, n.destination, direct, pax);
          calendars[calKey(n.origin, n.destination, direct, pax)] = c.outbound;
          calendars[calKey(n.destination, n.origin, direct, pax)] = c.inbound;
        }
      }

      // 2. which (leg, day) need flight details
      const wantedDays = {};
      const daySigs = {};
      for (const n of needs) {
        const direct = isDirect(n.watch), pax = n.watch.min_seats;
        const lk = legKey(n.origin, n.destination, direct);
        let days = dayList(n.dates, today);
        if (s.prefilter) {
          const cal = calendars[calKey(n.origin, n.destination, direct, pax)];
          days = days.filter((d) => cal[d] && wanted(n.watch, cal[d]));
          for (const d of days) (daySigs[`${lk}|${d}`] ||= {})[pax] = sig(cal[d]);
        }
        wantedDays[lk] ||= new Set();
        days.forEach((d) => wantedDays[lk].add(d));
      }

      // 3. details for changed days, cache for unchanged
      const flights = {};
      for (const [lk, days] of Object.entries(wantedDays)) {
        const [o, d, directFlag] = lk.split('-');
        const direct = directFlag === '1';
        for (const day of [...days].sort()) {
          const fk = `${lk}|${day}`;
          const cached = state.flights[fk];
          let unchanged = s.prefilter && cached && now() - cached.at < s.detail_max_age * 1000;
          for (const [pax, sg] of Object.entries(daySigs[fk] || {})) {
            unchanged = unchanged && (state.calendar[calKey(o, d, direct, pax)] || {})[day] === sg;
          }
          if (unchanged) { flights[fk] = cached.flights; continue; }
          log(`fetching flights ${o}→${d} ${day}`);
          const fl = await api.flights(o, d, day, direct);
          state.flights[fk] = { at: now(), flights: fl };
          save();
          flights[fk] = fl;
        }
      }

      // 4. everything fetched: commit calendars (an aborted sweep leaves them untouched, so it is redone)
      for (const [k, cal] of Object.entries(calendars)) {
        state.calendar[k] = Object.fromEntries(Object.entries(cal).map(([d, seats]) => [d, sig(seats)]));
      }

      // 5. match + diff + notify
      let total = 0;
      for (const w of cfg.watches) {
        let matches = [];
        for (const n of legNeeds(w)) {
          const lk = legKey(n.origin, n.destination, isDirect(w));
          for (const day of wantedDays[lk] || []) {
            if (day >= n.dates.from && day <= n.dates.to) matches.push(...matchFlights(n, flights[`${lk}|${day}`] || []));
          }
        }
        const raw = [...new Map(matches.map((m) => [m.key, m])).values()];
        total += await diff(w, applyRoundTrip(w, raw), raw, notifyOn);
      }
      save();
      return total;
    }

    /**
     * Updates state.matches[w.name]. Each entry:
     *   { desc, cabin, seats, peak, leg, date, time, status: active|gone|unpaired, since, first, notified }
     * "unpaired" = still has seats but no longer combines with a return (require_both_legs).
     * Lost entries stay listed (see prune) so you can see what was missed.
     */
    async function diff(w, matches, raw, notifyOn) {
      const before = state.matches[w.name] || {};
      const current = Object.fromEntries(matches.map((m) => [m.key, m]));
      const rawByKey = Object.fromEntries(raw.map((m) => [m.key, m]));
      const ts = new Date(now()).toISOString();
      const after = {};

      for (const [k, m] of Object.entries(current)) {
        const old = before[k] && { status: 'active', desc: before[k].line, peak: before[k].seats, ...before[k] };
        const e = { desc: m.desc, cabin: m.cabin, seats: m.seats, peak: Math.max(old?.peak ?? 0, m.seats), leg: m.leg,
          date: m.flight.departure_date, time: m.flight.departure_time, status: 'active',
          since: old?.status === 'active' ? old.since || old.first : ts, first: old?.first ?? ts, notified: old?.notified ?? false };
        if (!old) {
          event(w.name, 'new', m.line);
        } else if (old.status !== 'active') {
          event(w.name, 'back', m.line);
          e.notified = false; // available again: alert again
        } else if (old.seats !== m.seats) {
          event(w.name, m.seats < old.seats ? 'down' : 'up', `${m.desc}, ${CABINS[m.cabin]} ×${old.seats} → ×${m.seats}`);
        }
        after[k] = e;
      }

      for (const [k, old0] of Object.entries(before)) {
        if (after[k]) continue;
        const old = { status: 'active', desc: old0.line, peak: old0.seats, ...old0 };
        const r = rawByKey[k];
        if (r) {
          if (old.status !== 'unpaired') event(w.name, 'unpaired', `${r.line} – no matching return`);
          after[k] = { ...old, seats: r.seats, peak: Math.max(old.peak, r.seats), status: 'unpaired',
            since: old.status === 'unpaired' ? old.since : ts };
        } else {
          if (old.status !== 'gone') event(w.name, 'gone', `${old.desc}, ${seatText(old.cabin, old.seats)}`);
          after[k] = { ...old, status: 'gone', since: old.status === 'gone' ? old.since : ts };
        }
      }
      state.matches[w.name] = after;

      const fresh = matches.filter((m) => !after[m.key].notified)
        .sort((a, b) => (a.leg > b.leg ? -1 : a.leg < b.leg ? 1 : 0) ||
          (a.flight.departure_date + a.flight.departure_time).localeCompare(b.flight.departure_date + b.flight.departure_time));
      if (!fresh.length) {
        log(`[${w.name}] ${matches.length} active match(es), nothing new`);
        return 0;
      }
      const lines = fresh.map((m) => m.line);
      log(`[${w.name}] ${fresh.length} new match(es):\n  ${lines.join('\n  ')}`);
      if (notifyOn) {
        const body = lines.slice(0, 25).join('\n') + (lines.length > 25 ? `\n…and ${lines.length - 25} more` : '');
        const data = { watch: w.name, matches: fresh.map((m) => ({ leg: m.leg, origin: m.origin, destination: m.destination,
          cabin: m.cabin, seats: m.seats, ...m.flight })) };
        if (!(await notify(`SAS award seats: ${w.name}`, body, data))) {
          log(`[${w.name}] notification failed, will retry next sweep`, 'warn');
          return fresh.length;
        }
      }
      fresh.forEach((m) => { after[m.key].notified = true; });
      return fresh.length;
    }

    return { runCycle, estimate };
  }

  const core = { validateConfig, migrateWatch, parseCalendar, parseFlight, createWatcher, legNeeds, applyRoundTrip, DEFAULT_CONFIG };
  if (typeof module === 'object' && module.exports) { module.exports = core; return; } // node tests

  // ================================================================ browser runtime

  class Blocked extends Error {}
  const sleep = (ms) => new Promise((r) => setTimeout(r, ms));
  const gmGet = (k, d) => { try { const v = GM_getValue(k); return v === undefined ? d : JSON.parse(v); } catch { return d; } };
  const gmSet = (k, v) => GM_setValue(k, JSON.stringify(v));

  const logLines = [];
  function log(msg, level = 'info') {
    const line = `${new Date().toLocaleTimeString('sv-SE')} ${level === 'info' ? '' : level.toUpperCase() + ' '}${msg}`;
    (level === 'warn' ? console.warn : console.log)('[sas-bonus-watch]', msg);
    logLines.unshift(line);
    logLines.length = Math.min(logLines.length, 200);
    ui.render();
  }

  // -- config & state
  let cfg, cfgError = null;
  const rawConfig = gmGet('config', DEFAULT_CONFIG);
  try { cfg = validateConfig(rawConfig); } catch (e) { cfgError = e.message; }
  const state = gmGet('state', {});
  const saveState = () => gmSet('state', state);

  // -- notifications
  function gmPost(url, body, headers = {}) {
    return new Promise((resolve, reject) => GM_xmlhttpRequest({
      method: 'POST', url, data: JSON.stringify(body), timeout: 15000,
      headers: { 'Content-Type': 'application/json', ...headers },
      onload: (r) => (r.status < 300 ? resolve(r) : reject(new Error(`HTTP ${r.status} ${r.responseText?.slice(0, 200)}`))),
      onerror: () => reject(new Error('network error')),
      ontimeout: () => reject(new Error('timeout')),
    }));
  }

  const NTFY_PRIORITY = { min: 1, low: 2, default: 3, high: 4, urgent: 5, max: 5 };
  async function sendOne(n, title, body, data) {
    if (n.type === 'ntfy') {
      const u = new URL(n.url); // https://ntfy.sh/topic -> publish JSON to the server root
      await gmPost(u.origin + '/', { topic: u.pathname.replace(/^\/+/, ''), title, message: body, tags: ['airplane'],
        priority: NTFY_PRIORITY[n.priority] || +n.priority || 3 });
    } else if (n.type === 'discord') {
      await gmPost(n.url, { content: `**${title}**\n${body}`.slice(0, 2000) });
    } else if (n.type === 'slack') {
      await gmPost(n.url, { text: `*${title}*\n${body}` });
    } else {
      await gmPost(n.url, { title, body, ...data });
    }
  }

  async function notify(title, body, data = {}) {
    if (cfg?.settings.desktop_notifications) {
      try { GM_notification({ title, text: body, timeout: 0 }); } catch (e) { log(`desktop notification failed: ${e}`, 'warn'); }
    }
    if (!cfg?.notify.length) return true;
    let ok = false;
    for (const n of cfg.notify) {
      try { await sendOne(n, title, body, data); ok = true; } catch (e) { log(`notify via ${n.type} failed: ${e.message}`, 'warn'); }
    }
    return ok;
  }

  // -- polite client
  const client = {
    nextAllowed: 0, failures: 0, requests: 0,
    async get(path, params) {
      const s = cfg.settings;
      const wait = this.nextAllowed - Date.now();
      if (wait > 0) await sleep(wait);
      this.nextAllowed = Date.now() + (s.min_request_interval + Math.random() * s.jitter) * 1000;
      this.requests++;
      const url = `${location.origin}/bff/award-finder/${path}?${new URLSearchParams(params)}`;
      let r;
      try {
        r = await fetch(url, { headers: { Accept: 'application/json' }, credentials: 'same-origin', cache: 'no-store' });
      } catch (e) {
        this.penalize(`network error: ${e.message}\n  ${url}`);
        throw new Blocked(e.message);
      }
      const ct = r.headers.get('content-type') || '';
      if (!r.ok || !ct.includes('json')) {
        this.penalize(`HTTP ${r.status} (${ct || 'no content-type'})\n  ${url}`);
        throw new Blocked(`HTTP ${r.status}`);
      }
      if (this.failures >= 2) notify('SAS bonus watch recovered', 'Requests are succeeding again.');
      this.failures = 0;
      status.blocked = false;
      return r.json();
    },
    penalize(reason) {
      this.failures++;
      const backoff = Math.min(cfg.settings.min_request_interval * 2 ** this.failures, 3600);
      this.nextAllowed = Date.now() + backoff * 1000;
      log(`${reason} - backing off ${Math.round(backoff)} s`, 'warn');
      if (this.failures === 2) {
        status.blocked = true;
        notify('SAS bonus watch is being refused',
          `${reason.split('\n')[0]}. Reload the ${location.href} tab; if sas.se shows a check, pass it.`);
      }
    },
  };

  const api = {
    async calendar(o, d, direct, pax) {
      return parseCalendar(await client.get('destinations/v1', { market: cfg.settings.market, origin: o, destinations: d,
        selectedMonth: '', passengers: pax, direct, availability: true }), d);
    },
    async flights(o, d, day, direct) {
      const data = await client.get('routes/v1', { market: cfg.settings.market, origin: o, destination: d,
        departureDate: day, direct });
      return (data || []).map(parseFlight);
    },
  };

  // -- single-tab lock, so two open tabs don't double the request rate
  const TAB_ID = Math.random().toString(36).slice(2);
  function holdLock() {
    const l = gmGet('lock', null);
    if (l && l.id !== TAB_ID && Date.now() - l.ts < 180000) return false;
    gmSet('lock', { id: TAB_ID, ts: Date.now() });
    return true;
  }
  window.addEventListener('pagehide', () => { if (gmGet('lock', null)?.id === TAB_ID) gmSet('lock', null); });

  // -- main loop
  const status = { phase: 'starting', lastCycle: null, nextCycle: null, blocked: false, paused: gmGet('paused', false) };
  let wake = null;
  const interruptibleSleep = (ms) => new Promise((r) => { const t = setTimeout(r, ms); wake = () => { clearTimeout(t); r(); }; });

  async function mainLoop() {
    if (cfgError) { status.phase = 'config error'; ui.render(); return; }
    if (!cfg.watches.length) { status.phase = 'no active watches'; ui.render(); return; }
    const watcher = createWatcher({ cfg, api, state, save: saveState, notify, log });
    log(`budget: ${watcher.estimate()}; ≥${cfg.settings.min_request_interval} s between requests, sweep every ${cfg.settings.cycle_interval} s`);
    setInterval(() => { if (status.phase !== 'other tab') holdLock(); }, 30000);

    for (;;) {
      const started = Date.now();
      if (status.paused) {
        status.phase = 'paused';
      } else if (!holdLock()) {
        status.phase = 'other tab';
        log('another tab is running the watcher; this one is idle', 'warn');
      } else {
        status.phase = 'sweeping';
        ui.render();
        const before = client.requests;
        try {
          const n = await watcher.runCycle(!gmGet('baseline', false));
          if (gmGet('baseline', false)) { gmSet('baseline', false); log('baseline recorded; future sweeps alert on new seats only'); }
          log(`sweep done: ${client.requests - before} request(s), ${n} new match(es)`);
        } catch (e) {
          if (!(e instanceof Blocked)) { log(`sweep failed: ${e.stack || e}`, 'warn'); } else { log(`sweep aborted (${e.message}); will retry`, 'warn'); }
        }
        status.lastCycle = new Date();
        status.phase = 'waiting';
      }
      const delay = status.phase === 'other tab' ? 60000 : Math.max(0, cfg.settings.cycle_interval * 1000 - (Date.now() - started));
      status.nextCycle = new Date(Date.now() + delay);
      ui.render();
      await interruptibleSleep(delay);
    }
  }

  // -- dashboard
  const ui = (() => {
    const h = (tag, attrs = {}, ...kids) => {
      const el = document.createElement(tag);
      for (const [k, v] of Object.entries(attrs)) {
        if (k.startsWith('on')) el.addEventListener(k.slice(2), v);
        else if (k === 'checked' || k === 'disabled' || k === 'value' || k === 'selected') el[k] = v;
        else if (v != null && v !== false) el.setAttribute(k, v === true ? '' : v);
      }
      for (const kid of kids.flat()) if (kid != null && kid !== false) el.append(kid);
      return el;
    };
    const css = `
      :root { --bg:#fafaf9; --fg:#1c1917; --muted:#78716c; --card:#fff; --line:#e7e5e4; --acc:#1d4ed8; --ok:#15803d; --warn:#b45309; --bad:#b91c1c; --input:#fff; }
      @media (prefers-color-scheme: dark) { :root { --bg:#0c0a09; --fg:#e7e5e4; --muted:#a8a29e; --card:#1c1917; --line:#292524; --acc:#60a5fa; --ok:#4ade80; --warn:#fbbf24; --bad:#f87171; --input:#0c0a09; } }
      * { box-sizing: border-box; }
      body { margin:0; background:var(--bg); color:var(--fg); font:14px/1.45 system-ui, sans-serif; }
      main { max-width: 1200px; margin: 0 auto; padding: 24px 16px 64px; }
      h1 { font-size: 20px; margin: 0 0 4px; } h2 { font-size: 15px; margin: 28px 0 8px; } h3 { font-size: 13px; margin: 16px 0 6px; color: var(--muted); }
      h3:first-child { margin-top: 0; }
      .muted { color: var(--muted); } .small { font-size: 12px; }
      .pill { display:inline-block; padding:1px 8px; border-radius:99px; font-size:12px; border:1px solid currentColor; margin-left:8px; vertical-align:2px; }
      .ok { color: var(--ok); } .warn { color: var(--warn); } .bad { color: var(--bad); }
      .card { background: var(--card); border: 1px solid var(--line); border-radius: 8px; padding: 12px 14px; }
      .btns { display:flex; flex-wrap:wrap; gap:8px; margin: 12px 0; align-items: center; }
      button { font: inherit; padding: 6px 12px; border-radius: 6px; border: 1px solid var(--line); background: var(--card); color: var(--fg); cursor: pointer; }
      button.primary { background: var(--acc); border-color: var(--acc); color: #fff; }
      button.icon { padding: 2px 8px; color: var(--muted); }
      button:disabled { opacity: .5; cursor: default; }
      table { width:100%; border-collapse: collapse; font-variant-numeric: tabular-nums; }
      td, th { text-align:left; padding: 4px 6px 4px 0; border-bottom: 1px solid var(--line); vertical-align: middle; }
      th { font-weight: 600; color: var(--muted); font-size: 12px; white-space: nowrap; }
      input, select { font: inherit; font-size: 13px; color: var(--fg); background: var(--input); border: 1px solid var(--line); border-radius: 5px; padding: 3px 5px; }
      input[type=checkbox] { width: 16px; height: 16px; accent-color: var(--acc); vertical-align: -3px; }
      input.code { width: 8.5em; text-transform: uppercase; } input.name { width: 11em; } input.num { width: 4.2em; } input.url { width: 100%; min-width: 22em; }
      label.cab { white-space: nowrap; margin-right: 6px; font-size: 13px; }
      tr.off td { opacity: .45; } tr.off td:first-child { opacity: 1; }
      td.seats { white-space: nowrap; font-variant-numeric: tabular-nums; }
      tr.gone td { color: var(--bad); } tr.gone td.desc, tr.gone td.seats { text-decoration: line-through; }
      tr.unpaired td.desc, tr.unpaired td.seats { color: var(--muted); }
      pre { margin:0; white-space: pre-wrap; word-break: break-word; font: 12px/1.5 ui-monospace, monospace; max-height: 320px; overflow:auto; }
      textarea { width:100%; min-height: 360px; font: 12px/1.5 ui-monospace, monospace; background: var(--input); color: var(--fg); border:1px solid var(--line); border-radius:8px; padding:10px; }
      details > summary { cursor: pointer; color: var(--muted); margin: 10px 0 6px; }
      .err { white-space: pre-wrap; color: var(--bad); }
      .scroll { overflow-x: auto; }
    `;

    // ---- live status ---------------------------------------------------------
    const live = {};

    function render() {
      if (!live.header) return;
      const t = (d) => (d ? d.toLocaleTimeString('sv-SE') : '–');
      const phase = cfgError ? 'config error' : status.blocked ? 'blocked – reload this tab' : status.phase;
      const cls = cfgError || status.blocked ? 'bad' : ['paused', 'other tab', 'no active watches'].includes(status.phase) ? 'warn' : 'ok';
      live.header.replaceChildren(
        h('h1', {}, 'SAS bonus watch', h('span', { class: `pill ${cls}` }, phase)),
        h('div', { class: 'muted' },
          `Last sweep ${t(status.lastCycle)} · next ${t(status.nextCycle)} · ${client.requests} request(s) since load · keep this tab open`));
      live.pause.textContent = status.paused ? 'Resume' : 'Pause';

      const when = (iso) => new Date(iso).toLocaleString('sv-SE', { month: 'short', day: 'numeric', hour: '2-digit', minute: '2-digit' });
      const order = { active: 0, unpaired: 1, gone: 2 };
      live.matches.replaceChildren(...(cfg?.watches || []).map((w) => {
        const rows = Object.values(state.matches?.[w.name] || {}).map((r) => ({ status: 'active', desc: r.line, peak: r.seats, ...r }))
          .sort((a, b) => order[a.status] - order[b.status] || (a.leg > b.leg ? -1 : a.leg < b.leg ? 1 : 0) ||
            (a.date + a.time).localeCompare(b.date + b.time));
        const active = rows.filter((r) => r.status === 'active').length;
        const seatsCell = (r) => h('td', { class: 'seats' },
          r.cabin ? `${CABINS[r.cabin].replace('SAS ', '')} ×${r.seats}` : '',
          r.status !== 'gone' && r.peak > r.seats ? h('span', { class: 'bad', title: `was ×${r.peak}` }, ` −${r.peak - r.seats}`) : null);
        const statusCell = (r) => r.status === 'gone'
          ? h('td', { class: 'bad' }, `gone ${when(r.since)}`)
          : r.status === 'unpaired'
            ? h('td', { class: 'muted', title: 'Still has seats, but no return in your window fits with it' }, 'no matching return')
            : h('td', { class: 'muted' }, `since ${when(r.first)}`);
        return h('div', { class: 'card', style: 'margin-bottom:10px' },
          h('strong', {}, w.name), ' ',
          h('span', { class: 'muted' }, `${w.origins.join('/')} ⇄ ${w.destinations.join('/')} · ${w.window.from} → ${w.window.to}` +
            ` · ${w.cabins.join('/')} · ≥${w.min_seats} seat(s)` + (w.require_both_legs ? ' · both legs' : '') +
            ` · ${active} bookable`),
          rows.length
            ? h('div', { class: 'scroll' }, h('table', {},
              h('tr', {}, h('th', {}, 'Flight'), h('th', {}, 'Seats'), h('th', {}, 'Status')),
              rows.map((r) => h('tr', { class: r.status }, h('td', { class: 'desc' }, r.desc), seatsCell(r), statusCell(r)))))
            : h('div', { class: 'muted', style: 'margin-top:6px' }, 'No matching seats right now.'));
      }));

      const mark = { new: ['+', 'ok'], back: ['+', 'ok'], up: ['▲', 'ok'], down: ['▼', 'bad'], gone: ['−', 'bad'], unpaired: ['○', 'muted'] };
      const events = (state.events || []).slice(0, 80);
      live.events.replaceChildren(...(events.length ? events.map((e) => {
        const [sym, cls] = mark[e.kind] || ['−', 'bad'];
        return h('div', {}, h('span', { class: 'muted' }, `${when(e.ts)}  `), h('span', { class: cls }, `${sym} `),
          h('span', { class: 'muted' }, `[${e.watch}] `), e.kind === 'back' ? 'back: ' : '', e.line);
      }) : ['Nothing yet.']));
      live.log.textContent = logLines.join('\n');
    }

    // ---- config editor (tables edit a draft; JSON is export/import of the same draft) ----
    const clone = (o) => JSON.parse(JSON.stringify(o));
    const normalizeDraft = (raw) => {
      const d = clone(raw || {});
      d.settings = { ...DEFAULT_CONFIG.settings, ...(d.settings || {}) };
      d.notify = d.notify || [];
      d.watches = (d.watches || []).map(migrateWatch).map((w) => ({ enabled: true, require_both_legs: true, ...w }));
      return d;
    };
    let draft = normalizeDraft(rawConfig);
    let dirty = false;
    const ed = {};

    const setDirty = (on) => {
      dirty = on;
      ed.save.disabled = ed.discard.disabled = !on;
      ed.dirtyNote.textContent = on ? 'Unsaved changes' : '';
      if (on) ed.errors.textContent = '';
    };
    const bind = (obj, key, parse = (v) => v) => ({
      oninput: (e) => { obj[key] = parse(e.target.type === 'checkbox' ? e.target.checked : e.target.value); setDirty(true); },
    });
    const optInt = (v) => (v === '' ? null : Number(v));
    const codes = (v) => String(v).split(/[\s,;/]+/).map((c) => c.trim().toUpperCase()).filter(Boolean);
    const removeBtn = (list, i, title) => h('button', { class: 'icon', title, onclick: () => { list.splice(i, 1); setDirty(true); renderEditor(); } }, '✕');

    function watchRow(w, i) {
      const cabinBoxes = Object.entries(CABINS).map(([code, label]) => h('label', { class: 'cab', title: label },
        h('input', { type: 'checkbox', checked: (w.cabins || []).includes(code), onchange: (e) => {
          const set = new Set(w.cabins || []);
          if (e.target.checked) set.add(code); else set.delete(code);
          w.cabins = Object.keys(CABINS).filter((c) => set.has(c));
          setDirty(true);
        } }), ` ${label.replace('SAS ', '')}`));
      const tr = h('tr', { class: w.enabled === false ? 'off' : null },
        h('td', {}, h('input', { type: 'checkbox', title: 'Enabled', checked: w.enabled !== false,
          onchange: (e) => { w.enabled = e.target.checked; tr.className = w.enabled ? '' : 'off'; setDirty(true); } })),
        h('td', {}, h('input', { class: 'name', value: w.name || '', placeholder: 'Name', ...bind(w, 'name') })),
        h('td', {}, h('input', { class: 'code', value: (w.origins || []).join(', '), placeholder: 'ARN, CPH', ...bind(w, 'origins', codes) })),
        h('td', {}, h('input', { class: 'code', value: (w.destinations || []).join(', '), placeholder: 'HND, NRT', ...bind(w, 'destinations', codes) })),
        h('td', {}, h('input', { type: 'date', value: w.from || '', ...bind(w, 'from') })),
        h('td', {}, h('input', { type: 'date', value: w.to || '', ...bind(w, 'to') })),
        h('td', { style: 'white-space:nowrap' }, cabinBoxes),
        h('td', {}, h('input', { class: 'num', type: 'number', min: 1, max: 9, value: w.min_seats ?? 1, ...bind(w, 'min_seats', Number) })),
        h('td', {}, h('select', { ...bind(w, 'max_stops', optInt) },
          [['', 'Any'], ['0', 'Direct'], ['1', '≤ 1'], ['2', '≤ 2']].map(([v, l]) =>
            h('option', { value: v, selected: String(w.max_stops ?? '') === v }, l)))),
        h('td', { title: 'Only alert when an outbound and a return both fit in the window' },
          h('input', { type: 'checkbox', checked: w.require_both_legs !== false, ...bind(w, 'require_both_legs') })),
        h('td', { style: 'white-space:nowrap' },
          h('input', { class: 'num', type: 'number', min: 0, placeholder: 'min', value: w.min_nights ?? '', ...bind(w, 'min_nights', optInt) }),
          ' – ',
          h('input', { class: 'num', type: 'number', min: 0, placeholder: 'max', value: w.max_nights ?? '', ...bind(w, 'max_nights', optInt) })),
        h('td', {}, removeBtn(draft.watches, i, 'Remove watch')));
      return tr;
    }

    function notifyRow(n, i) {
      return h('tr', {},
        h('td', {}, h('select', { ...bind(n, 'type') }, ['ntfy', 'discord', 'slack', 'webhook'].map((t) =>
          h('option', { value: t, selected: n.type === t }, t)))),
        h('td', { style: 'width:100%' }, h('input', { class: 'url', value: n.url || '', placeholder: 'https://ntfy.sh/your-topic', ...bind(n, 'url') })),
        h('td', {}, h('select', { title: 'Priority (ntfy only)', ...bind(n, 'priority') }, ['', 'low', 'default', 'high', 'urgent'].map((p) =>
          h('option', { value: p, selected: (n.priority || '') === p }, p || '–')))),
        h('td', {}, removeBtn(draft.notify, i, 'Remove notification')));
    }

    function renderEditor() {
      const st = draft.settings;
      const numSetting = (key, label, min) => h('label', { style: 'margin-right:16px; white-space:nowrap' }, `${label} `,
        h('input', { class: 'num', type: 'number', min, value: st[key], ...bind(st, key, Number) }));
      ed.tables.replaceChildren(
        h('h3', {}, 'Watches'),
        h('div', { class: 'small muted', style: 'margin-bottom:6px' },
          'Finds outbound and return flights departing between Earliest and Latest. Airports are comma-separated codes; every From × To pair is checked.'),
        h('div', { class: 'scroll' }, h('table', {},
          h('tr', {}, ['On', 'Name', 'From', 'To', 'Earliest', 'Latest', 'Cabins', 'Seats', 'Stops', 'Both legs', 'Nights', '']
            .map((c) => h('th', {}, c))),
          draft.watches.map(watchRow))),
        h('div', { class: 'btns' }, h('button', { onclick: () => {
          const today = todayISO();
          draft.watches.push({ name: `watch ${draft.watches.length + 1}`, enabled: true, origins: ['ARN'], destinations: [],
            from: today, to: addDays(today, 14), cabins: ['AG', 'AP', 'AB'], min_seats: 1, max_stops: null, require_both_legs: true });
          setDirty(true);
          renderEditor();
        } }, '+ Add watch')),

        h('h3', {}, 'Notifications'),
        h('div', { class: 'scroll' }, h('table', {},
          h('tr', {}, ['Type', 'URL', 'Priority', ''].map((c) => h('th', {}, c))),
          draft.notify.map(notifyRow))),
        h('div', { class: 'btns' },
          h('button', { onclick: () => { draft.notify.push({ type: 'ntfy', url: '', priority: 'high' }); setDirty(true); renderEditor(); } },
            '+ Add notification'),
          h('label', {}, h('input', { type: 'checkbox', checked: st.desktop_notifications, ...bind(st, 'desktop_notifications') }),
            ' Desktop notifications')),

        h('details', {}, h('summary', {}, 'Request pacing'),
          h('div', { class: 'small' },
            numSetting('min_request_interval', 'Seconds between requests (≥ 20)', 20),
            numSetting('jitter', '+ random up to', 0),
            numSetting('cycle_interval', 'Seconds between sweeps', 60))));
    }

    function jsonSection() {
      const json = h('textarea', { spellcheck: 'false' });
      const msg = h('div', { class: 'small' });
      const apply = () => {
        try {
          const parsed = normalizeDraft(JSON.parse(json.value));
          validateConfig(parsed);
          draft = parsed;
          setDirty(true);
          renderEditor();
          msg.className = 'small ok';
          msg.textContent = 'Loaded into the tables above. Press "Save & restart" to use it.';
        } catch (e) { msg.className = 'small err'; msg.textContent = e.message; }
      };
      const file = h('input', { type: 'file', accept: '.json,application/json', style: 'display:none', onchange: async (e) => {
        const f = e.target.files[0];
        if (f) { json.value = await f.text(); apply(); }
        e.target.value = '';
      } });
      return h('details', { ontoggle: (e) => { if (e.target.open) json.value = JSON.stringify(draft, null, 2); } },
        h('summary', {}, 'JSON – export / import / reset'),
        h('div', { class: 'small muted', style: 'margin-bottom:6px' },
          'The config as currently edited above. Edit or paste JSON and apply it to the tables, or save it to a file as a backup.'),
        json,
        h('div', { class: 'btns' },
          h('button', { onclick: apply }, 'Apply JSON to tables'),
          h('button', { onclick: () => {
            const a = h('a', { href: URL.createObjectURL(new Blob([JSON.stringify(draft, null, 2)], { type: 'application/json' })),
              download: `sas-bonus-watch-${todayISO()}.json` });
            a.click();
            setTimeout(() => URL.revokeObjectURL(a.href), 1000);
          } }, 'Download .json'),
          h('button', { onclick: () => file.click() }, 'Load file…'),
          file,
          h('button', { onclick: () => { if (confirm('Replace the config with the example?')) { json.value = JSON.stringify(DEFAULT_CONFIG, null, 2); apply(); } } },
            'Reset to example')),
        msg);
    }

    function mount() {
      document.title = 'SAS bonus watch';
      document.head.append(h('meta', { name: 'viewport', content: 'width=device-width, initial-scale=1' }), h('style', {}, css));
      live.header = h('div');
      live.matches = h('div');
      live.events = h('pre');
      live.log = h('pre');
      live.pause = h('button', { onclick: () => {
        status.paused = !status.paused;
        gmSet('paused', status.paused);
        if (!status.paused) wake?.();
        render();
      } });

      ed.tables = h('div');
      ed.errors = h('div', { class: 'err' }, cfgError ? `The saved config has problems:\n${cfgError}` : '');
      ed.dirtyNote = h('span', { class: 'warn small' });
      ed.save = h('button', { class: 'primary', disabled: true, onclick: () => {
        try {
          validateConfig(draft);
          gmSet('config', draft);
          dirty = false;
          location.reload();
        } catch (e) { ed.errors.textContent = e.message; }
      } }, 'Save & restart');
      ed.discard = h('button', { disabled: true, onclick: () => {
        draft = normalizeDraft(rawConfig);
        setDirty(false);
        ed.errors.textContent = '';
        renderEditor();
      } }, 'Discard changes');

      document.body.replaceChildren(h('main', {},
        live.header,
        h('div', { class: 'btns' },
          h('button', { class: 'primary', onclick: () => { status.paused = false; gmSet('paused', false); wake?.(); } }, 'Sweep now'),
          live.pause,
          h('button', { onclick: async () => log((await notify('SAS bonus watch: test', 'Notifications work.'))
            ? 'test notification sent' : 'test notification failed') }, 'Test notification'),
          h('button', { onclick: () => { gmSet('baseline', true); log('next sweep records current seats without alerting'); wake?.(); } },
            'Baseline (no alerts)'),
          h('button', { onclick: () => { if (confirm('Forget seen matches and cached data?')) { gmSet('state', {}); location.reload(); } } },
            'Reset state')),
        h('h2', {}, 'Current matches'), live.matches,
        h('h2', {}, 'Config'),
        h('div', { class: 'card' }, ed.tables,
          h('div', { class: 'btns', style: 'margin-top:16px' }, ed.save, ed.discard, ed.dirtyNote),
          ed.errors,
          jsonSection()),
        h('h2', {}, 'Recent changes'), h('div', { class: 'card' }, live.events),
        h('h2', {}, 'Log'), h('div', { class: 'card' }, live.log)));
      window.addEventListener('beforeunload', (e) => { if (dirty) e.preventDefault(); });
      renderEditor();
      render();
    }
    return { mount, render };
  })();

  ui.mount();
  mainLoop();
})();