import { showToast } from '../services/channels-ux.js';
import { createTopBar } from '../components/topbar.js';
import {
  isSessionInvalidError,
  refreshSessions,
  setAuthError,
  setAuthInfo,
  state,
  terminateCurrentSession,
} from '../state.js';

export const pageMeta = { id: 'device-view', title: 'Устройства' };

function formatSessionType(sessionType) {
  if (Number(sessionType) === 100) return 'Домашний сервер';
  if (Number(sessionType) === 50) return 'Кошелёк';
  if (Number(sessionType) === 1) return 'Приложение';
  return `Тип ${Number(sessionType) || 0}`;
}

// «Mozilla/5.0 (X11; Linux x86_64) … Chrome/139 …» → «Chrome · Linux».
function describeClient(userAgent) {
  const ua = String(userAgent || '');
  if (!ua) return 'Неизвестное устройство';
  const browser = /Edg\//.test(ua) ? 'Edge'
    : /OPR\/|Opera/.test(ua) ? 'Opera'
      : /Firefox\//.test(ua) ? 'Firefox'
        : /YaBrowser\//.test(ua) ? 'Яндекс Браузер'
          : /Chrome\//.test(ua) ? 'Chrome'
            : /Safari\//.test(ua) ? 'Safari'
              : '';
  const os = /iPhone/.test(ua) ? 'iPhone'
    : /iPad/.test(ua) ? 'iPad'
      : /Android/.test(ua) ? 'Android'
        : /Windows/.test(ua) ? 'Windows'
          : /Mac OS X|Macintosh/.test(ua) ? 'macOS'
            : /Linux|X11/.test(ua) ? 'Linux'
              : '';
  const parts = [browser, os].filter(Boolean);
  return parts.length ? parts.join(' · ') : ua.slice(0, 40);
}

// «сегодня, 02:20» / «вчера, 23:10» / «24 сентября, 18:05».
function formatSessionTime(ms) {
  const date = new Date(ms);
  const time = date.toLocaleTimeString('ru-RU', { hour: '2-digit', minute: '2-digit' });
  const startOf = (d) => new Date(d.getFullYear(), d.getMonth(), d.getDate()).getTime();
  const days = Math.round((startOf(new Date()) - startOf(date)) / 86400000);
  if (days === 0) return `сегодня, ${time}`;
  if (days === 1) return `вчера, ${time}`;
  const sameYear = date.getFullYear() === new Date().getFullYear();
  const day = date.toLocaleDateString('ru-RU', { day: 'numeric', month: 'long', ...(sameYear ? {} : { year: 'numeric' }) });
  return `${day}, ${time}`;
}

function formatOnlineStatus(onlineOnThisServer) {
  return onlineOnThisServer ? 'в сети' : 'не в сети';
}

function sortSessionsByOnline(sessions = []) {
  return [...sessions].sort((a, b) => {
    const aOnline = a?.onlineOnThisServer ? 1 : 0;
    const bOnline = b?.onlineOnThisServer ? 1 : 0;
    if (aOnline !== bOnline) return bOnline - aOnline;
    return Number(b?.lastAuthenticatedAtMs || 0) - Number(a?.lastAuthenticatedAtMs || 0);
  });
}

export function render({navigate, chrome}) {
  const screen = document.createElement('section');
  screen.className = 'stack';

  chrome?.setTopbar(createTopBar({
      title: 'Устройства',
      back: { label: '←', onClick: () => navigate('settings-view') },
      actions: [{ icon: 'refresh', title: 'Обновить список сеансов', ariaLabel: 'Обновить список сеансов', id: 'reload-sessions', onClick: () => reloadSessions() }],
    }));

  const actions = document.createElement('div');
  actions.className = 'nav-list';
  actions.innerHTML = `
    <button class="nav-row" type="button" id="pair-by-code-btn"><span class="nav-row__label">Подключить по коду</span><span class="nav-row__hint">Войти на другом устройстве по короткому коду</span></button>
    <button class="nav-row" type="button" id="connect-device-btn"><span class="nav-row__label">Другие способы подключения</span></button>
    <button class="nav-row" type="button" id="show-keys-btn"><span class="nav-row__label">Ключи этого устройства</span></button>
  `;

  actions.querySelector('#pair-by-code-btn').addEventListener('click', () => navigate('device-pairing-view'));
  actions.querySelector('#connect-device-btn').addEventListener('click', () => navigate('connect-device-view'));
  actions.querySelector('#show-keys-btn').addEventListener('click', () => navigate('show-keys-view'));

  const sessionsBlock = document.createElement('div');
  sessionsBlock.className = 'stack device-sessions';

  const buildList = () => {
    sessionsBlock.innerHTML = '';
    const sessions = sortSessionsByOnline(state.sessions || []);
    const current = sessions.find((s) => s.sessionId === state.session.sessionId) || sessions[0];
    const others = sortSessionsByOnline(sessions.filter((s) => s.sessionId !== current?.sessionId));

    const createSessionItem = (session, isCurrent) => {
      const item = document.createElement('button');
      item.className = 'ui-button session-item';
      item.type = 'button';
      const isWebClient = Number(session.sessionType) === 1 && /web/i.test(String(session.clientPlatform || ''));
      const sessionTypeText = isWebClient ? 'Браузер' : formatSessionType(session.sessionType);
      const sessionPlatformText = !isWebClient && session.clientPlatform ? ` · ${session.clientPlatform}` : '';
      const onlineStatusText = formatOnlineStatus(!!session.onlineOnThisServer);
      const onlineStatusClass = session.onlineOnThisServer ? 'session-status session-status--online' : 'session-status';
      item.innerHTML = `
        <span class="session-item__main">
          <strong class="session-item__title"></strong>
          <span class="meta-muted">${sessionTypeText}${sessionPlatformText} · <span class="${onlineStatusClass}">${onlineStatusText}</span></span>
          ${session.geo && session.geo !== 'unknown' ? '<span class="meta-muted session-item__geo"></span>' : ''}
        </span>
        <span class="session-item__side">
          <span class="meta-muted">${formatSessionTime(session.lastAuthenticatedAtMs || Date.now())}</span>
        </span>
      `;
      item.querySelector('.session-item__title').textContent = describeClient(session.clientInfoFromClient);
      item.title = String(session.clientInfoFromClient || '');
      const geoEl = item.querySelector('.session-item__geo');
      if (geoEl) geoEl.textContent = session.geo;
      item.addEventListener('click', () => navigate(`device-session-view/${session.sessionId}`));
      return item;
    };

    if (!current) {
      const empty = document.createElement('p');
      empty.className = 'meta-muted';
      empty.textContent = 'Активные сессии не найдены.';
      sessionsBlock.append(empty);
      return;
    }

    const groupTitle = (text) => {
      const title = document.createElement('p');
      title.className = 'nav-list__title';
      title.textContent = text;
      return title;
    };
    const currentList = document.createElement('div');
    currentList.className = 'nav-list';
    currentList.append(createSessionItem(current, true));
    sessionsBlock.append(groupTitle('Это устройство'), currentList, groupTitle('Другие сеансы'));

    if (others.length === 0) {
      const empty = document.createElement('p');
      empty.className = 'empty-note';
      empty.textContent = 'Других сеансов нет.';
      sessionsBlock.append(empty);
    } else {
      const othersList = document.createElement('div');
      othersList.className = 'nav-list';
      others.forEach((session) => othersList.append(createSessionItem(session, false)));
      sessionsBlock.append(othersList);
    }
  };

  async function reloadSessions() {
    try {
      await refreshSessions();
      buildList();
      setAuthInfo('Список сеансов обновлён.');
      showToast('Список сеансов обновлён');
    } catch (error) {
      if (isSessionInvalidError(error)) {
        await terminateCurrentSession({
          infoMessage: 'Сессия на этом устройстве уже завершена. Выполните вход заново.',
        });
        return;
      }
      setAuthError(error.message);
      showToast(error.message, { kind: 'error' });
    }
  }

  buildList();
  screen.append(actions, sessionsBlock);
  return screen;
}