// Pure helpers of the workspace: quoting paths for a shell, what a dropped
// file does where it lands, sizes. No DOM here, so node can test them.
(function (root) {
  'use strict';
  function shellQuote(p) { return "'" + String(p).replace(/'/g, "'\\''") + "'"; }
  function shellQuoteAll(ps) { return ps.map(shellQuote).join(' '); }
  const same = (a, b) => a.kind === b.kind && a.id === b.id;
  // dropAction says what dropping item on target does: a transfer between
  // file panes, paths pasted into a terminal of the same place, nothing on
  // its own folder, or a refusal with the reason.
  function dropAction(item, target) {
    if (target.kind === 'term') {
      return same(item.source, target.source) ? {kind: 'paste'}
        : {kind: 'deny', reason: 'Нельзя: файл на ' + item.source.label + ', а терминал на ' + target.source.label};
    }
    if (same(item.source, target.source) && target.dir === item.dir) return {kind: 'none'};
    return {kind: 'transfer'};
  }
  function fmtSize(n) {
    if (n < 1024) return n + ' B';
    if (n < 1048576) return (n / 1024).toFixed(1) + ' K';
    if (n < 1073741824) return (n / 1048576).toFixed(1) + ' M';
    return (n / 1073741824).toFixed(1) + ' G';
  }
  // scope gives a module timers, requests and listeners that end with it;
  // once ended it starts nothing new (a request's late answer cannot set a
  // timer going again).
  function scope() {
    let ended = false;
    const timers = new Set(), offs = [], ac = new AbortController();
    return {
      timeout(fn, ms) { if (ended) return 0; const id = setTimeout(() => { timers.delete(id); fn(); }, ms); timers.add(id); return id; },
      interval(fn, ms) { if (ended) return 0; const id = setInterval(fn, ms); timers.add(id); return id; },
      clear(id) { clearTimeout(id); clearInterval(id); timers.delete(id); },
      fetch(url, opt) {
        const o = Object.assign({credentials: 'same-origin'}, opt || {});
        // A request with its own signal ends on either.
        o.signal = o.signal && AbortSignal.any ? AbortSignal.any([o.signal, ac.signal]) : (o.signal || ac.signal);
        return fetch(url, o);
      },
      on(target, ev, fn, opt) { target.addEventListener(ev, fn, opt); offs.push(() => target.removeEventListener(ev, fn, opt)); },
      signal: ac.signal,
      end() { ended = true; timers.forEach(id => { clearTimeout(id); clearInterval(id); }); timers.clear(); offs.forEach(f => f()); ac.abort(); }
    };
  }

  const api = {shellQuote, shellQuoteAll, dropAction, fmtSize, scope};
  if (typeof module !== 'undefined') module.exports = api; else root.WSUtil = api;
})(this);