let authToken = localStorage.getItem('authToken') || null;

export function setAuthToken(token) {
  authToken = token;
  if (token) localStorage.setItem('authToken', token);
  else localStorage.removeItem('authToken');
}

async function request(method, url, body) {
  const headers = {};
  if (body) headers['Content-Type'] = 'application/json';
  if (authToken) headers['Authorization'] = `Bearer ${authToken}`;

  const res = await fetch(url, {
    method,
    headers,
    body: body ? JSON.stringify(body) : undefined,
  });
  if (!res.ok) {
    const text = await res.text().catch(() => '');
    let error;
    try {
      error = JSON.parse(text).error;
    } catch {
      error = text;
    }
    throw new Error(error || `${method} ${url} fehlgeschlagen: ${res.status}`);
  }
  const text = await res.text();
  return text ? JSON.parse(text) : null;
}

export const api = {
  // auth
  login: (email, password) => request('POST', '/api/auth/login', { email, password }),
  logout: () => request('POST', '/api/auth/logout'),
  me: () => request('GET', '/api/auth/me'),

  // vacations
  getVacations: () => request('GET', '/api/vacations'),
  createVacation: (data) => request('POST', '/api/vacations', data),
  updateVacation: (id, data) => request('PUT', `/api/vacations/${id}`, data),
  deleteVacation: (id) => request('DELETE', `/api/vacations/${id}`),

  // users
  getUsers: () => request('GET', '/api/users'),
  createUser: (data) => request('POST', '/api/users', data),
  updateUser: (id, data) => request('PUT', `/api/users/${id}`, data),
  deleteUser: (id) => request('DELETE', `/api/users/${id}`),

  // employees
  getEmployees: () => request('GET', '/api/employees'),
  createEmployee: (data) => request('POST', '/api/employees', data),
  updateEmployee: (id, data) => request('PUT', `/api/employees/${id}`, data),
  deleteEmployee: (id) => request('DELETE', `/api/employees/${id}`),

  // teams
  getTeams: () => request('GET', '/api/teams'),
  createTeam: (data) => request('POST', '/api/teams', data),
  updateTeam: (id, data) => request('PUT', `/api/teams/${id}`, data),
  deleteTeam: (id) => request('DELETE', `/api/teams/${id}`),
  addTeamMember: (teamId, employeeId) =>
    request('POST', `/api/teams/${teamId}/members`, { employee_id: employeeId }),
  removeTeamMember: (teamId, employeeId) =>
    request('DELETE', `/api/teams/${teamId}/members/${employeeId}`),

  // projects & tasks
  getProjects: () => request('GET', '/api/projects'),
  createProject: (data) => request('POST', '/api/projects', data),
  updateProject: (id, data) => request('PUT', `/api/projects/${id}`, data),
  deleteProject: (id) => request('DELETE', `/api/projects/${id}`),

  createTask: (data) => request('POST', '/api/tasks', data),
  updateTask: (id, data) => request('PUT', `/api/tasks/${id}`, data),
  deleteTask: (id) => request('DELETE', `/api/tasks/${id}`),
  duplicateTask: (id, data) => request('POST', `/api/tasks/${id}/duplicate`, data),
  addDependency: (taskId, dependsOnId) =>
    request('POST', `/api/tasks/${taskId}/dependencies`, { depends_on_task_id: dependsOnId }),
  removeDependency: (taskId, dependsOnId) =>
    request('DELETE', `/api/tasks/${taskId}/dependencies/${dependsOnId}`),

  // assignments
  createAssignment: (data) => request('POST', '/api/assignments', data),
  updateAssignment: (id, data) => request('PUT', `/api/assignments/${id}`, data),
  deleteAssignment: (id) => request('DELETE', `/api/assignments/${id}`),

  // utilization
  getUtilization: (params = {}) => {
    const qs = new URLSearchParams(params).toString();
    return request('GET', `/api/utilization${qs ? `?${qs}` : ''}`);
  },
};