import { renderHeader } from '../components/header.js?v=20260330001044';
import { channels as mockChannels } from '../mock-data.js?v=20260330001044';
import { authService, setChannelsFeed, state } from '../state.js?v=20260330001044';

export const pageMeta = { id: 'channels-list', title: 'Каналы' };

function openSimpleSubscribeModal(kindLabel) {
  const root = document.getElementById('modal-root');
  root.innerHTML = `
    <div class="modal" id="channels-subscribe-modal">
      <div class="modal-card stack">
        <h3 style="font-size:18px;">${kindLabel}</h3>
        <label class="meta-muted" for="subscribe-input">Введите идентификатор</label>
        <input id="subscribe-input" class="input" placeholder="@login или #канал" />
        <div style="display:grid; grid-template-columns:1fr 1fr; gap:10px;">
          <button class="secondary-btn" id="sub-cancel">Отмена</button>
          <button class="primary-btn" id="sub-submit">Подписаться</button>
        </div>
      </div>
    </div>
  `;

  const close = () => {
    root.innerHTML = '';
  };

  root.querySelector('#sub-cancel').addEventListener('click', close);
  root.querySelector('#sub-submit').addEventListener('click', close);
}

function initialsFromName(name = '') {
  const parts = name.split(/\s+/).filter(Boolean);
  return (parts[0]?.[0] || '#') + (parts[1]?.[0] || '');
}

function mapMockGroups() {
  const ownChannels = mockChannels.filter((channel) => channel.kind === 'own-personal' || channel.kind === 'own');
  const followedUserChannels = mockChannels.filter((channel) => channel.kind === 'followed-user-channel');
  const subscribedChannels = mockChannels.filter((channel) => channel.kind === 'subscribed');
  return { ownChannels, followedUserChannels, subscribedChannels, index: {} };
}

function mapApiChannelRow(summary, bucketKey, idx, index) {
  const rowId = `${bucketKey}-${idx}`;
  index[rowId] = summary;

  return {
    id: rowId,
    source: 'api',
    ownerName: summary.channel?.ownerLogin || 'unknown',
    initials: initialsFromName(summary.channel?.channelName || summary.channel?.ownerLogin || '?'),
    name: summary.channel?.channelName || '(без имени)',
    description: `owner=${summary.channel?.ownerLogin || '-'} / bch=${summary.channel?.ownerBlockchainName || '-'}`,
    lastMessage: summary.lastMessage?.text || 'Сообщений пока нет',
    time: summary.lastMessage?.createdAtMs ? new Date(summary.lastMessage.createdAtMs).toLocaleString('ru-RU') : '—',
    messagesCount: summary.messagesCount || 0,
  };
}

function mapApiFeed(feed) {
  const index = {};

  const ownChannels = (feed?.ownedChannels || []).map((it, idx) => mapApiChannelRow(it, 'own', idx, index));
  const followedUserChannels = (feed?.followedUsersChannels || []).map((it, idx) => mapApiChannelRow(it, 'followedUsers', idx, index));
  const subscribedChannels = (feed?.followedChannels || []).map((it, idx) => mapApiChannelRow(it, 'followedChannels', idx, index));

  ownChannels.sort((a, b) => {
    const ap = index[a.id]?.channel?.personal === true;
    const bp = index[b.id]?.channel?.personal === true;
    if (ap && !bp) return -1;
    if (!ap && bp) return 1;
    return a.name.localeCompare(b.name, 'ru');
  });

  return { ownChannels, followedUserChannels, subscribedChannels, index };
}

function renderChannelRow(channel, navigate) {
  const row = document.createElement('article');
  row.className = 'list-item';
  row.innerHTML = `
    <div class="avatar">${channel.initials}</div>
    <div>
      <strong># ${channel.name}</strong>
      <p class="meta-muted" style="margin-top:4px;">${channel.description}</p>
      <p class="meta-muted" style="margin-top:6px; color:#d8e3ff;">${channel.lastMessage}</p>
      <p class="meta-muted" style="margin-top:6px;">Владелец: ${channel.ownerName}</p>
    </div>
    <div style="display:grid; justify-items:end; gap:6px;">
      <span class="badge alt" style="padding:4px 8px; font-size:10px;">Канал</span>
      <span class="meta-muted">${channel.time}</span>
      <span class="unread">${channel.messagesCount}</span>
    </div>
  `;
  row.addEventListener('click', () => navigate(`channel-view/${channel.id}`));
  return row;
}

function renderSection(title, items, navigate) {
  const wrap = document.createElement('section');
  wrap.className = 'stack';

  const header = document.createElement('h3');
  header.className = 'section-title';
  header.textContent = title;

  wrap.append(header);
  items.forEach((channel) => wrap.append(renderChannelRow(channel, navigate)));

  return wrap;
}

function renderGroupedList(screen, navigate, groups) {
  const listWrap = document.createElement('div');
  listWrap.className = 'channels-scroll-wrap';

  const list = document.createElement('div');
  list.className = 'stack channels-groups';

  list.append(renderSection('Мои каналы', groups.ownChannels, navigate));

  const dividerOne = document.createElement('hr');
  dividerOne.className = 'channels-divider';
  list.append(dividerOne);

  list.append(renderSection('Каналы пользователей, на кого вы подписаны', groups.followedUserChannels, navigate));

  const dividerTwo = document.createElement('hr');
  dividerTwo.className = 'channels-divider';
  list.append(dividerTwo);

  list.append(renderSection('Каналы, на которые вы подписаны', groups.subscribedChannels, navigate));

  const addChannelButton = document.createElement('button');
  addChannelButton.className = 'primary-btn';
  addChannelButton.textContent = 'Добавить канал';
  addChannelButton.addEventListener('click', () => navigate('add-channel-view'));

  list.append(addChannelButton);

  const scrollHint = document.createElement('div');
  scrollHint.className = 'channels-scroll-hint';

  listWrap.append(list, scrollHint);
  screen.append(listWrap);
}

async function loadFeedAndRender(screen, navigate) {
  const status = document.createElement('div');
  status.className = 'card meta-muted';
  status.textContent = 'Загрузка каналов с сервера...';
  screen.append(status);

  try {
    if (!state.session.login) throw new Error('not_authorized');
    const feed = await authService.listSubscriptionsFeed(state.session.login, 200);
    const groups = mapApiFeed(feed);
    setChannelsFeed(feed, groups.index);
    status.remove();
    renderGroupedList(screen, navigate, groups);
  } catch {
    setChannelsFeed(null, {});
    status.textContent = 'Сервер недоступен или нет данных. Показаны демо-каналы.';
    renderGroupedList(screen, navigate, mapMockGroups());
  }
}

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

  screen.append(
    renderHeader({
      title: 'Каналы',
      rightActions: [
        { label: 'Подписаться на человека', onClick: () => openSimpleSubscribeModal('Подписка на человека') },
        { label: 'Подписаться на канал', onClick: () => openSimpleSubscribeModal('Подписка на канал') },
      ],
    })
  );

  loadFeedAndRender(screen, navigate);
  return screen;
}