const $ = (sel) => document.querySelector(sel);

const loginScreen = $('#login-screen');
const mainScreen = $('#main-screen');
const loginForm = $('#login-form');
const loginError = $('#login-error');
const usersBody = $('#users-body');
const userDialog = $('#user-dialog');
const userForm = $('#user-form');
const globalError = $('#global-error');
const globalOk = $('#global-ok');

let allGroups = [];
let allUsers = [];

async function api(path, opts = {}) {
  const res = await fetch(path, {
    headers: { 'Content-Type': 'application/json', ...(opts.headers || {}) },
    ...opts,
  });
  const data = await res.json().catch(() => ({}));
  if (!res.ok) throw new Error(data.error || `HTTP ${res.status}`);
  return data;
}

function showError(msg) {
  globalError.textContent = msg;
  globalError.classList.remove('hidden');
  globalOk.classList.add('hidden');
  setTimeout(() => globalError.classList.add('hidden'), 6000);
}

function showOk(msg) {
  globalOk.textContent = msg;
  globalOk.classList.remove('hidden');
  globalError.classList.add('hidden');
  setTimeout(() => globalOk.classList.add('hidden'), 4000);
}

function formatBytes(n) {
  if (n == null || n === '?' || isNaN(Number(n))) return '—';
  const b = Number(n);
  if (b === 0) return '0 B';
  const u = ['B', 'KB', 'MB', 'GB', 'TB'];
  const i = Math.min(Math.floor(Math.log(b) / Math.log(1024)), u.length - 1);
  return `${(b / 1024 ** i).toFixed(1)} ${u[i]}`;
}

function escapeHtml(s) {
  return String(s).replace(/[&<>"']/g, (c) => ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[c]));
}

async function checkSession() {
  try {
    const me = await api('/api/me');
    loginScreen.classList.add('hidden');
    mainScreen.classList.remove('hidden');
    $('#server-info').textContent = `${me.username} @ ${me.nextcloudUrl}`;
    await loadAll();
  } catch {
    loginScreen.classList.remove('hidden');
    mainScreen.classList.add('hidden');
  }
}

async function loadGroups() {
  const { groups } = await api('/api/groups');
  allGroups = groups || [];
  const sel = $('#field-groups');
  sel.innerHTML = allGroups.map((g) => `<option value="${escapeHtml(g)}">${escapeHtml(g)}</option>`).join('');
}

async function loadUsers() {
  usersBody.innerHTML = '<tr><td colspan="8" class="muted center">Загрузка…</td></tr>';
  const { users } = await api('/api/users');
  allUsers = users;

  if (!users.length) {
    usersBody.innerHTML = '<tr><td colspan="8" class="muted center">Нет пользователей</td></tr>';
    return;
  }

  usersBody.innerHTML = users.map((u) => `
    <tr>
      <td><strong>${escapeHtml(u.id)}</strong></td>
      <td>${escapeHtml(u.displayName || '—')}</td>
      <td>${escapeHtml(u.email || '—')}</td>
      <td>${escapeHtml(String(u.quota || 'default'))}</td>
      <td>${formatBytes(u.used)}</td>
      <td>${(u.groups || []).map((g) => `<span class="group-tag">${escapeHtml(g)}</span>`).join('') || '—'}</td>
      <td><span class="badge ${u.enabled ? 'on' : 'off'}">${u.enabled ? 'активен' : 'отключён'}</span></td>
      <td class="row-actions">
        <button class="secondary small btn-edit" data-id="${escapeHtml(u.id)}">Изменить</button>
        <button class="danger small btn-del" data-id="${escapeHtml(u.id)}" ${u.id === 'admin' ? 'disabled title="Нельзя удалить admin"' : ''}>Удалить</button>
      </td>
    </tr>
  `).join('');

  document.querySelectorAll('.btn-edit').forEach((btn) => {
    btn.addEventListener('click', () => openEdit(btn.dataset.id));
  });
  document.querySelectorAll('.btn-del').forEach((btn) => {
    btn.addEventListener('click', () => deleteUser(btn.dataset.id));
  });
}

async function loadAll() {
  try {
    await Promise.all([loadGroups(), loadUsers()]);
  } catch (e) {
    showError(e.message);
  }
}

function getQuotaValue() {
  const sel = $('#field-quota').value;
  if (sel === 'custom') return $('#field-quota-custom').value.trim();
  if (sel === 'none') return 'none';
  if (sel === 'default') return 'default';
  return sel;
}

function setQuotaSelect(quota) {
  const q = String(quota || 'default');
  const sel = $('#field-quota');
  const opts = [...sel.options].map((o) => o.value);
  if (q === 'none' || q === 'default') {
    sel.value = q;
  } else if (opts.includes(q)) {
    sel.value = q;
  } else {
    sel.value = 'custom';
    $('#field-quota-custom').value = q;
  }
  $('#custom-quota-wrap').classList.toggle('hidden', sel.value !== 'custom');
}

function openCreate() {
  $('#dialog-title').textContent = 'Новый пользователь';
  $('#edit-userid').value = '';
  $('#field-userid').value = '';
  $('#field-userid').disabled = false;
  $('#field-password').value = '';
  $('#field-password').required = true;
  $('#password-hint').textContent = 'Обязателен для нового пользователя';
  $('#field-displayname').value = '';
  $('#field-email').value = '';
  setQuotaSelect('default');
  $('#field-enabled').checked = true;
  $('#field-enabled-wrap').classList.add('hidden');
  [...$('#field-groups').options].forEach((o) => { o.selected = o.value === 'users'; });
  userDialog.showModal();
}

function openEdit(userid) {
  const u = allUsers.find((x) => x.id === userid);
  if (!u) return;

  $('#dialog-title').textContent = `Редактировать: ${userid}`;
  $('#edit-userid').value = userid;
  $('#field-userid').value = userid;
  $('#field-userid').disabled = true;
  $('#field-password').value = '';
  $('#field-password').required = false;
  $('#password-hint').textContent = 'Оставьте пустым, чтобы не менять';
  $('#field-displayname').value = u.displayName || '';
  $('#field-email').value = u.email || '';
  setQuotaSelect(u.quota);
  $('#field-enabled').checked = u.enabled !== false;
  $('#field-enabled-wrap').classList.remove('hidden');

  const groups = u.groups || [];
  [...$('#field-groups').options].forEach((o) => { o.selected = groups.includes(o.value); });

  userDialog.showModal();
}

async function deleteUser(id) {
  if (!confirm(`Удалить пользователя «${id}»? Файлы будут удалены.`)) return;
  try {
    await api(`/api/users/${encodeURIComponent(id)}`, { method: 'DELETE' });
    showOk(`Пользователь ${id} удалён`);
    await loadUsers();
  } catch (e) {
    showError(e.message);
  }
}

loginForm.addEventListener('submit', async (e) => {
  e.preventDefault();
  loginError.classList.add('hidden');
  try {
    await api('/api/login', {
      method: 'POST',
      body: JSON.stringify({
        username: $('#login-user').value.trim(),
        password: $('#login-pass').value,
      }),
    });
    await checkSession();
  } catch {
    loginError.textContent = 'Неверный логин или пароль';
    loginError.classList.remove('hidden');
  }
});

$('#btn-logout').addEventListener('click', async () => {
  await api('/api/logout', { method: 'POST' });
  location.reload();
});

$('#btn-refresh').addEventListener('click', loadAll);
$('#btn-create').addEventListener('click', openCreate);
$('#btn-cancel').addEventListener('click', () => userDialog.close());

$('#field-quota').addEventListener('change', () => {
  $('#custom-quota-wrap').classList.toggle('hidden', $('#field-quota').value !== 'custom');
});

userForm.addEventListener('submit', async (e) => {
  e.preventDefault();

  const editId = $('#edit-userid').value;
  const quota = getQuotaValue();
  const selectedGroups = [...$('#field-groups').selectedOptions].map((o) => o.value);

  try {
    if (editId) {
      const body = {
        quota,
        displayName: $('#field-displayname').value.trim(),
        email: $('#field-email').value.trim(),
        enabled: $('#field-enabled').checked,
      };
      const pass = $('#field-password').value;
      if (pass) body.password = pass;

      await api(`/api/users/${encodeURIComponent(editId)}`, {
        method: 'PATCH',
        body: JSON.stringify(body),
      });

      const u = allUsers.find((x) => x.id === editId);
      const currentGroups = u?.groups || [];

      for (const g of selectedGroups) {
        if (!currentGroups.includes(g)) {
          await api(`/api/users/${encodeURIComponent(editId)}/groups`, {
            method: 'POST',
            body: JSON.stringify({ groupid: g }),
          });
        }
      }
      for (const g of currentGroups) {
        if (!selectedGroups.includes(g) && g !== 'admin') {
          await api(`/api/users/${encodeURIComponent(editId)}/groups/${encodeURIComponent(g)}`, {
            method: 'DELETE',
          });
        }
      }

      showOk(`Пользователь ${editId} обновлён`);
    } else {
      const userid = $('#field-userid').value.trim();
      const password = $('#field-password').value;
      if (!password) throw new Error('Укажите пароль');

      await api('/api/users', {
        method: 'POST',
        body: JSON.stringify({ userid, password, quota, groups: selectedGroups }),
      });
      showOk(`Пользователь ${userid} создан`);
    }

    userDialog.close();
    await loadAll();
  } catch (err) {
    showError(err.message);
  }
});

checkSession();