import { renderHeader } from '../components/header.js';
import { authService, state } from '../state.js';
import { toUserMessage } from '../services/ui-error-texts.js';
import {
  normalizeChannelDisplayName,
  validateChannelDisplayName,
} from '../services/channel-name-rules.js';
import {
  getArweaveAttachmentAvailability,
  openArweaveAttachmentManager,
  markArweaveAttachmentPlaced,
} from '../components/arweave-attachment-manager.js';
import { renderAvatar } from '../components/avatar-image.js';
import { makeShineChannelRoute } from '../services/shine-routes.js';

export const pageMeta = { id: 'add-channel-view', title: 'Создание канала' };

const CREATE_CHANNEL_FLASH_KEY = 'shine-channels-create-success';
const CHANNEL_TYPE_PUBLIC = 1;
const CHANNEL_LOGIN_HINT = 'Разрешены латинские буквы, цифры, _ и -. Длина: от 3 до 32 символов. Название не должно состоять только из цифр.';
const CHANNEL_LOGIN_DIGITS_ONLY_HINT = 'Имя канала не должно состоять только из цифр.';

function persistCreateSuccessFlash(message) {
  try {
    sessionStorage.setItem(CREATE_CHANNEL_FLASH_KEY, String(message || '').trim());
  } catch {
    // ignore storage errors
  }
}

function normalizeMetaText(value, max, label) {
  const normalized = String(value || '').trim();
  const length = Array.from(normalized).length;
  if (length > max) {
    return { ok: false, normalized, length, error: `${label}: максимум ${max} символов.` };
  }
  return { ok: true, normalized, length, error: '' };
}

function renderAvatarPreview(slot, avatar, title) {
  if (!slot) return;
  slot.innerHTML = '';
  const label = String(title || 'К').trim() || 'К';
  const wrap = renderAvatar({
    initials: label.slice(0, 1).toUpperCase() || 'К',
    avatar,
    size: 'small',
    className: 'channel-profile-avatar',
    title: label,
    alt: 'Аватар канала',
  });
  wrap.style.setProperty('--channel-avatar-size', '104px');
  slot.append(wrap);
}

function buildAbsoluteChannelUrl({ ownerBlockchainName = '', channelName = '' } = {}) {
  const route = makeShineChannelRoute({ ownerBlockchainName, channelName });
  if (!route) return '';
  try {
    return new URL(`/${route}`, window.location.origin).toString();
  } catch {
    return `${window.location.origin}/${route}`;
  }
}

function sanitizeChannelLoginInput(value) {
  const source = String(value || '');
  let result = '';
  for (const ch of source) {
    if (/[A-Za-z0-9_-]/.test(ch)) result += ch;
  }
  return result.slice(0, 32);
}

function shortAvatarBlockchainAddress(value) {
  const raw = String(value || '').trim();
  if (raw.length <= 24) return raw;
  return raw.slice(-24);
}

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

  screen.append(
    renderHeader({
      title: 'Создание канала',
      leftAction: { label: '<', onClick: () => navigate('channels-list') },
    }),
  );

  const form = document.createElement('form');
  form.className = 'card stack';
  form.innerHTML = `
    <div class="channel-create-avatar-head">
      <div id="channel-avatar-preview"></div>
      <div class="channel-create-avatar-side">
        <div class="channel-create-avatar-status-row">
          <div class="channel-create-avatar-status" id="channel-avatar-status"></div>
          <button type="button" class="channel-avatar-remove-btn" id="channel-avatar-remove" title="Убрать аватар" aria-label="Убрать аватар">✕</button>
        </div>
        <button type="button" class="secondary-btn" id="channel-avatar-btn">Выбрать аватар</button>
      </div>
    </div>

    <label for="channel-name">Технический логин канала</label>
    <input id="channel-name" class="input" maxlength="32" placeholder="Например: My-Channel_1" required />
    <div class="meta-muted channel-create-login-hint">${CHANNEL_LOGIN_HINT}</div>
    <div class="meta-muted channel-link-preview" id="channel-link-preview">&nbsp;</div>
    <div id="channel-name-error" class="meta-muted inline-error"></div>

    <label for="channel-title">Как канал будет виден пользователям</label>
    <input id="channel-title" class="input" maxlength="50" placeholder="Например: Мой красивый канал" />
    <div class="meta-muted" id="channel-title-counter">0 / 50 символов</div>
    <div id="channel-title-error" class="meta-muted inline-error"></div>

    <label for="channel-description">Описание канала (необязательно)</label>
    <textarea id="channel-description" class="input" rows="4" maxlength="250" placeholder="Коротко о канале, до 250 символов"></textarea>
    <div class="meta-muted" id="channel-description-counter">0 / 250 символов</div>
    <div id="channel-description-error" class="meta-muted inline-error"></div>

    <div id="channel-create-error" class="meta-muted inline-error"></div>
    <div class="form-actions-grid">
      <button type="button" class="secondary-btn" id="cancel-create-channel">Отмена</button>
      <button type="submit" class="primary-btn" id="submit-create-channel">Создать</button>
    </div>
  `;

  const nameEl = form.querySelector('#channel-name');
  const titleEl = form.querySelector('#channel-title');
  const descriptionEl = form.querySelector('#channel-description');
  const avatarPreviewEl = form.querySelector('#channel-avatar-preview');
  const avatarStatusEl = form.querySelector('#channel-avatar-status');
  const avatarBtn = form.querySelector('#channel-avatar-btn');
  const avatarRemoveBtn = form.querySelector('#channel-avatar-remove');
  const linkPreviewEl = form.querySelector('#channel-link-preview');
  const nameErrorEl = form.querySelector('#channel-name-error');
  const titleErrorEl = form.querySelector('#channel-title-error');
  const titleCounterEl = form.querySelector('#channel-title-counter');
  const descriptionErrorEl = form.querySelector('#channel-description-error');
  const descriptionCounterEl = form.querySelector('#channel-description-counter');
  const errorEl = form.querySelector('#channel-create-error');
  const submitEl = form.querySelector('#submit-create-channel');
  const cancelEl = form.querySelector('#cancel-create-channel');

  let submitInFlight = false;
  let selectedAvatar = null;
  let ownerBlockchainName = '';
  let avatarAvailabilityLabel = '';
  let avatarAvailabilityTxId = '';

  const renderAvatarStatus = (nameValue, titleValue) => {
    renderAvatarPreview(avatarPreviewEl, selectedAvatar, titleValue || nameValue);
    avatarRemoveBtn.hidden = !selectedAvatar?.ar;
    if (!selectedAvatar?.ar) {
      avatarStatusEl.innerHTML = '<p class="channel-avatar-status-text">Аватар канала не установлен.</p>';
      return;
    }
    const txId = String(selectedAvatar.ar || '').trim();
    const shortTxId = shortAvatarBlockchainAddress(txId);
    const isPending = avatarAvailabilityLabel === 'pending' || avatarAvailabilityTxId !== txId;
    avatarStatusEl.innerHTML = `
      <p class="channel-avatar-status-text">Аватар канала</p>
      <p class="channel-avatar-status-line">Адрес аватара в блокчейне Arweave <span class="channel-avatar-txid">${shortTxId}</span><span class="channel-avatar-status-pending">${isPending ? ', ещё не обновился в блокчейне.' : ''}</span></p>
    `;
  };

  const renderChannelLinkPreview = (nameValue) => {
    const normalizedChannelName = normalizeChannelDisplayName(nameValue);
    if (!ownerBlockchainName || !normalizedChannelName) {
      linkPreviewEl.innerHTML = '&nbsp;';
      return;
    }
    const directUrl = buildAbsoluteChannelUrl({
      ownerBlockchainName,
      channelName: normalizedChannelName,
    });
    linkPreviewEl.innerHTML = `Прямая ссылка: <a href="${directUrl}" target="_blank" rel="noopener noreferrer">${directUrl}</a>`;
  };

  const refreshAvatarAvailability = async () => {
    const txId = String(selectedAvatar?.ar || '').trim();
    avatarAvailabilityTxId = txId;
    avatarAvailabilityLabel = txId ? 'pending' : '';
    renderAvatarStatus(nameEl.value, titleEl.value);
    if (!txId) return;
    try {
      const availability = await getArweaveAttachmentAvailability({
        gateway: state.entrySettings.arweaveServer,
        attachment: selectedAvatar,
      });
      if (avatarAvailabilityTxId !== txId) return;
      avatarAvailabilityLabel = String(availability?.status || '').trim().toLowerCase();
    } catch {
      if (avatarAvailabilityTxId !== txId) return;
      avatarAvailabilityLabel = 'pending';
    }
    renderAvatarStatus(nameEl.value, titleEl.value);
  };

  const setBusy = (busy) => {
    submitInFlight = !!busy;
    submitEl.disabled = submitInFlight;
    cancelEl.disabled = submitInFlight;
    nameEl.disabled = submitInFlight;
    titleEl.disabled = submitInFlight;
    descriptionEl.disabled = submitInFlight;
    avatarBtn.disabled = submitInFlight;
    submitEl.textContent = submitInFlight ? 'Создаём...' : 'Создать';
  };

  const updateValidation = () => {
    const nameCheck = validateChannelDisplayName(nameEl.value);
    const titleCheck = normalizeMetaText(titleEl.value, 50, 'Название');
    const descriptionCheck = normalizeMetaText(descriptionEl.value, 250, 'Описание');

    nameErrorEl.textContent = '';
    titleErrorEl.textContent = titleCheck.error;
    descriptionErrorEl.textContent = descriptionCheck.error;

    titleCounterEl.textContent = `${Number(titleCheck.length || 0)} / 50 символов`;
    descriptionCounterEl.textContent = `${Number(descriptionCheck.length || 0)} / 250 символов`;

    const ok = nameCheck.ok && titleCheck.ok && descriptionCheck.ok;
    submitEl.disabled = submitInFlight || !ok;
    renderAvatarStatus(nameCheck.normalized, titleCheck.normalized);
    renderChannelLinkPreview(nameCheck.normalized);

    return {
      ok,
      name: nameCheck.normalized,
      title: titleCheck.normalized,
      description: descriptionCheck.normalized,
    };
  };

  nameEl.addEventListener('input', () => {
    const raw = String(nameEl.value || '');
    const sanitized = sanitizeChannelLoginInput(raw);
    if (raw !== sanitized) {
      nameEl.value = sanitized;
      window.alert(CHANNEL_LOGIN_HINT);
    }
    updateValidation();
  });
  titleEl.addEventListener('input', updateValidation);
  descriptionEl.addEventListener('input', updateValidation);
  avatarBtn.addEventListener('click', async () => {
    try {
      const nextAvatar = await openArweaveAttachmentManager({
        login: state.session.login,
        storagePwd: state.session.storagePwdInMemory,
        gateway: state.entrySettings.arweaveServer,
        mode: 'avatar',
        historyPurpose: 'avatar',
      });
      if (nextAvatar?.ar) {
        selectedAvatar = nextAvatar;
        void refreshAvatarAvailability();
      }
      updateValidation();
    } catch (error) {
      errorEl.textContent = toUserMessage(error, 'Не удалось выбрать аватар.');
    }
  });

  avatarRemoveBtn.addEventListener('click', () => {
    if (!selectedAvatar?.ar) return;
    const confirmed = window.confirm('Убрать аватар и сделать канал без аватара?');
    if (!confirmed) return;
    selectedAvatar = null;
    avatarAvailabilityLabel = '';
    avatarAvailabilityTxId = '';
    updateValidation();
  });

  form.addEventListener('submit', async (event) => {
    event.preventDefault();
    if (submitInFlight) return;

    const login = state.session.login;
    const storagePwd = state.session.storagePwdInMemory;
    if (!login || !storagePwd) {
      errorEl.textContent = 'Сессия недействительна. Выполните вход заново.';
      return;
    }

    const check = updateValidation();
    if (check.name && /^[0-9]+$/.test(check.name)) {
      window.alert(CHANNEL_LOGIN_DIGITS_ONLY_HINT);
      nameEl.focus();
      return;
    }
    if (!check.ok) return;

    setBusy(true);
    errorEl.textContent = '';

    try {
      await authService.addBlockCreateChannel({
        login,
        storagePwd,
        channelName: normalizeChannelDisplayName(check.name),
        channelDescription: check.description,
        channelProfileTitle: check.title,
        channelAvatar: selectedAvatar,
        channelType: CHANNEL_TYPE_PUBLIC,
        channelTypeVersion: 1,
      });
      if (selectedAvatar?.ar) markArweaveAttachmentPlaced(login, selectedAvatar);

      persistCreateSuccessFlash(`Канал "${normalizeChannelDisplayName(check.name)}" создан.`);
      navigate('channels-list');
    } catch (error) {
      errorEl.textContent = toUserMessage(error, 'Не удалось создать канал.');
      setBusy(false);
      updateValidation();
    }
  });

  cancelEl.addEventListener('click', () => navigate('channels-list'));

  screen.append(form);
  nameEl.focus();
  updateValidation();
  void authService.getUser(String(state.session.login || '').trim())
    .then((user) => {
      ownerBlockchainName = String(user?.blockchainName || '').trim();
      renderChannelLinkPreview(nameEl.value);
    })
    .catch(() => {
      ownerBlockchainName = '';
      renderChannelLinkPreview(nameEl.value);
    });
  return screen;
}