import { renderHeader } from '../components/header.js';
import {
  authService,
  clearAuthMessages,
  setAuthBusy,
  setAuthError,
  state,
} from '../state.js';
import { toUserMessage } from '../services/ui-error-texts.js';
import {
  composePasswordFromWords,
  emptyPasswordWords,
  normalizePasswordWords,
  PASSWORD_MAX_LENGTH,
  PASSWORD_WORDS_COUNT,
} from '../services/password-words.js';

function createWordsLayout({ words, onInput }) {
  const section = document.createElement('div');
  section.className = 'registration-words-block';

  const grid = document.createElement('div');
  grid.className = 'registration-words-grid';

  const inputs = Array.from({ length: PASSWORD_WORDS_COUNT }, (_, index) => {
    const row = document.createElement('label');
    row.className = 'registration-word-row';

    const number = document.createElement('span');
    number.className = 'registration-word-number';
    number.textContent = `${index + 1}.`;

    const input = document.createElement('input');
    input.className = 'input registration-word-input';
    input.type = 'text';
    input.autocomplete = 'off';
    input.autocapitalize = 'off';
    input.spellcheck = false;
    input.maxLength = 32;
    input.value = words[index];
    input.addEventListener('input', () => onInput(index, input.value));

    row.append(number, input);
    grid.append(row);
    return input;
  });

  const hint = document.createElement('p');
  hint.className = 'meta-muted';
  hint.textContent =
    'Можно вводить любые слова на любых языках. Можно заполнить не все 12 полей. В конце они просто склеиваются в один пароль длиной до 256 символов.';

  const preview = document.createElement('p');
  preview.className = 'status-line';

  section.append(grid, hint);
  return { section, inputs, preview };
}

export const pageMeta = { id: 'login-password-view', title: 'Войти по логину', showAppChrome: false };

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

  clearAuthMessages();

  const form = document.createElement('div');
  form.className = 'card stack';

  let passwordMode = String(state.loginDraft.passwordMode || 'single') === 'words' ? 'words' : 'single';
  let passwordWords = normalizePasswordWords(state.loginDraft.passwordWords);

  const loginInput = document.createElement('input');
  loginInput.className = 'input';
  loginInput.type = 'text';
  loginInput.autocomplete = 'off';
  loginInput.autocapitalize = 'off';
  loginInput.spellcheck = false;
  loginInput.value = state.loginDraft.login;
  loginInput.placeholder = 'Введите логин';

  const passwordInput = document.createElement('input');
  passwordInput.className = 'input';
  passwordInput.type = 'password';
  passwordInput.name = 'shine-login-password';
  passwordInput.autocomplete = 'new-password';
  passwordInput.autocapitalize = 'off';
  passwordInput.spellcheck = false;
  passwordInput.maxLength = PASSWORD_MAX_LENGTH;
  passwordInput.value = passwordMode === 'single' ? state.loginDraft.password : '';
  passwordInput.placeholder = 'Введите пароль';

  const {
    section: wordsSection,
    inputs: wordInputs,
    preview: wordsPreview,
  } = createWordsLayout({
    words: passwordWords,
    onInput: (index, value) => {
      passwordWords[index] = value;
      syncDraftState();
    },
  });

  const passwordModeToggle = document.createElement('label');
  passwordModeToggle.className = 'registration-toggle';

  const passwordModeCheckbox = document.createElement('input');
  passwordModeCheckbox.type = 'checkbox';
  passwordModeCheckbox.checked = passwordMode === 'words';

  const passwordModeLabel = document.createElement('span');
  passwordModeLabel.textContent = 'Представить пароль в виде 12 слов';

  passwordModeToggle.append(passwordModeCheckbox, passwordModeLabel);

  const hint = document.createElement('p');
  hint.className = 'meta-muted';
  hint.textContent = 'Введите логин. На следующем шаге сохраните ключи на устройстве.';

  const status = document.createElement('p');
  status.className = 'status-line is-unavailable';
  status.style.display = 'none';

  let passwordField = null;
  const passwordLengthText = document.createElement('p');
  passwordLengthText.className = 'status-line';

  function getCurrentPassword() {
    return passwordMode === 'words' ? composePasswordFromWords(passwordWords) : String(passwordInput.value || '');
  }

  function syncDraftState() {
    state.loginDraft.login = loginInput.value.trim();
    state.loginDraft.passwordMode = passwordMode;
    state.loginDraft.passwordWords = normalizePasswordWords(passwordWords);
    state.loginDraft.password = getCurrentPassword();
  }

  function updateWordsPreview() {
    const password = getCurrentPassword();
    const text = `Итоговая длина пароля: ${password.length} символов.`;
    wordsPreview.textContent = text;
    passwordLengthText.textContent = text;
  }

  function updatePasswordModeVisibility() {
    const wordsMode = passwordMode === 'words';
    wordsSection.style.display = wordsMode ? 'grid' : 'none';
    if (passwordField) passwordField.style.display = wordsMode ? 'none' : 'grid';
    passwordInput.style.display = wordsMode ? 'none' : '';
    updateWordsPreview();
  }

  form.innerHTML = `
    <label class="stack"><span class="field-label">Логин</span></label>
    <label class="stack"><span class="field-label">Пароль</span></label>
  `;
  form.children[0].append(loginInput);
  passwordField = form.children[1];
  passwordField.append(passwordInput);
  form.append(passwordModeToggle, wordsSection, passwordLengthText, hint, status);
  updatePasswordModeVisibility();
  syncDraftState();

  loginInput.addEventListener('input', syncDraftState);
  passwordInput.addEventListener('input', syncDraftState);

  passwordModeCheckbox.addEventListener('change', () => {
    const nextMode = passwordModeCheckbox.checked ? 'words' : 'single';
    if (nextMode === passwordMode) return;
    if (nextMode === 'words') {
      passwordWords = emptyPasswordWords();
      wordInputs.forEach((input) => {
        input.value = '';
      });
      passwordInput.value = '';
    } else {
      passwordInput.value = composePasswordFromWords(passwordWords);
    }
    passwordMode = nextMode;
    updatePasswordModeVisibility();
    syncDraftState();
  });

  const actions = document.createElement('div');
  actions.className = 'auth-footer-actions';

  const backButton = document.createElement('button');
  backButton.className = 'ghost-btn';
  backButton.type = 'button';
  backButton.textContent = 'Назад';
  backButton.addEventListener('click', () => navigate('start-view'));

  const enterButton = document.createElement('button');
  enterButton.className = 'primary-btn';
  enterButton.type = 'button';
  enterButton.textContent = 'Войти';
  enterButton.addEventListener('click', async () => {
    status.style.display = 'none';
    syncDraftState();

    if (!state.loginDraft.login) {
      status.textContent = 'Введите логин.';
      status.style.display = '';
      return;
    }
    if (state.loginDraft.password.length > PASSWORD_MAX_LENGTH) {
      status.textContent = `Пароль слишком длинный. Максимальная длина: ${PASSWORD_MAX_LENGTH} символов.`;
      status.style.display = '';
      return;
    }

    setAuthBusy(true);
    setAuthError('');
    enterButton.disabled = true;
    enterButton.textContent = 'Входим...';

    try {
      await authService.reconnect(state.entrySettings.shineServer);
      const result = await authService.createSessionForExistingUser(state.loginDraft.login, state.loginDraft.password);
      state.registrationDraft.flowType = 'login';
      state.registrationDraft.login = result.login;
      state.registrationDraft.password = state.loginDraft.password;
      state.registrationDraft.passwordMode = state.loginDraft.passwordMode;
      state.registrationDraft.passwordWords = normalizePasswordWords(state.loginDraft.passwordWords);
      state.registrationDraft.sessionId = result.sessionId;
      state.registrationDraft.storagePwd = result.storagePwd;
      state.registrationDraft.pendingKeyBundle = result.keyBundle;
      state.registrationDraft.pendingSessionMaterial = result.sessionMaterial;
      navigate('registration-keys-view');
    } catch (error) {
      const message = toUserMessage(error, 'Не удалось выполнить вход.');
      setAuthError(message);
      status.textContent = message;
      status.style.display = '';
    } finally {
      setAuthBusy(false);
      enterButton.disabled = false;
      enterButton.textContent = 'Войти';
    }
  });

  actions.append(backButton, enterButton);

  screen.append(
    renderHeader({
      title: 'Войти по логину',
      leftAction: { label: '←', onClick: () => navigate('start-view') },
    }),
    form,
    actions,
  );

  return screen;
}