'use strict';
/* ──────────────────────────────────────────────────────────────────
   Exam Preparation Module — common helpers
   Loaded by every exam-prep*.html page before its view-specific JS.

   Responsibilities:
   - Parse examKey from URL path: /exam-prep/<key>[/...]
   - Determine current view (dashboard | variants | practice | topics | mock)
   - Render the tabs bar with the active tab highlighted
   - Expose helpers on window.EP
   ────────────────────────────────────────────────────────────────── */

(function () {
  const VIEWS = [
    { id: 'dashboard', label: 'Дашборд',  icon: 'gauge',          path: '' },
    { id: 'variants',  label: 'Варианты', icon: 'layout-grid',    path: '/variants' },
    { id: 'practice',  label: 'Тренажёр', icon: 'dumbbell',       path: '/practice' },
    { id: 'topics',    label: 'Темы',     icon: 'tag',            path: '/topics' },
    { id: 'mock',      label: 'Пробник',  icon: 'timer',          path: '/mock' },
  ];

  /* Parse examKey and view from `/exam-prep/<key>[/<view>[/...]]` */
  function parseUrl() {
    const parts = location.pathname.replace(/\/+$/, '').split('/').filter(Boolean);
    // parts[0] === 'exam-prep'; parts[1] === examKey; parts[2] === optional view
    const examKey = parts[1] || 'math9';
    const view    = (parts[2] && VIEWS.find(v => v.id === parts[2]))
                      ? parts[2]
                      : 'dashboard';
    return { examKey, view };
  }

  function renderTabs(containerSel, { examKey, view }) {
    const el = document.querySelector(containerSel);
    if (!el) return;
    el.innerHTML = VIEWS.map(v => {
      const href   = `/exam-prep/${examKey}${v.path}`;
      const active = v.id === view ? ' active' : '';
      return `<a class="ep-tab${active}" href="${href}">
        <i data-lucide="${v.icon}"></i><span>${v.label}</span>
      </a>`;
    }).join('');
    if (window.lucide && typeof lucide.createIcons === 'function') lucide.createIcons();
  }

  /* Bootstrap shared for every exam-prep page.
     - Reads {examKey, view}
     - Initializes LS auth/page chrome
     - Renders the tabs bar (if a #ep-tabs slot exists)
     - Loads track info and writes it into #ep-title / #ep-sub if present
     - Returns the {track, counts, progress} payload to the caller (Promise) */
  async function boot(opts = {}) {
    const { examKey, view } = parseUrl();

    if (typeof LS !== 'undefined') {
      LS.initPage?.();
      LS.showBoardIfAllowed?.();
      LS.hideDisabledFeatures?.();
    }

    renderTabs(opts.tabsSelector || '#ep-tabs', { examKey, view });

    let info = null;
    try {
      info = await LS.api(`/api/exam-prep/${examKey}/info`);
    } catch (e) {
      if (e && e.status === 403) { window.location.replace('/403'); return { examKey, view, info: null }; }
      console.warn('[exam-prep] info failed', e);
    }

    if (info?.track) {
      const titleEl = document.getElementById('ep-title');
      const subEl   = document.getElementById('ep-sub');
      if (titleEl) titleEl.textContent = info.track.title;
      if (subEl) {
        const c = info.counts || {};
        subEl.textContent =
          `${info.track.variants_count} вариантов · ${c.total ?? '—'} задач · ` +
          `${info.track.duration_min} мин`;
      }
    }

    window.EP = window.EP || {};
    window.EP.examKey = examKey;
    window.EP.view    = view;
    window.EP.info    = info;
    return { examKey, view, info };
  }

  window.EP = {
    boot, parseUrl, renderTabs, VIEWS,
  };
})();