frontend/src/services/apiClient.js

import { useAuthStore } from '@/stores/authStore.js';

const BASE_URL = 'http://localhost:9000/api/v2';

let isRefreshing = false;
let refreshPromise = null;

function createConfig(options = {}) {
  const authStore = useAuthStore();
  const headers = {
    'Content-Type': 'application/json',
    ...options.headers,
  };

  if (authStore.accessToken) {
    headers['Authorization'] = `Bearer ${authStore.accessToken}`;
  }

  return {
    headers,
    credentials: 'include',
    ...options,
  };
}

async function refreshAccessToken() {
  const authStore = useAuthStore();

  if (isRefreshing) return refreshPromise;

  isRefreshing = true;
  refreshPromise = fetch(`${BASE_URL}/user/auth/refresh`, {
    method: 'POST',
    credentials: 'include',
  })
    .then(async (res) => {
      if (!res.ok) throw new Error('Failed to refresh access token');
      return res.json();
    })
    .then((data) => {
      authStore.setToken(data.accessToken);
      return data;
    })
    .catch((error) => {
      throw error;
    })
    .finally(() => {
      isRefreshing = false;
      refreshPromise = null;
    });

  return refreshPromise;
}

async function request(url, options = {}, isRetry = false) {
  const config = createConfig(options);

  const response = await fetch(`${BASE_URL}${url}`, config);

  if (response.status === 401 && !isRetry) {
    try {
      const data = await refreshAccessToken();

      const newOptions = {
        ...options,
        headers: {
          ...options.headers,
          'Authorization': `Bearer ${data.accessToken}`,
        },
      };
      return await request(url, newOptions, true);
    } catch (e) {
      const authStore = useAuthStore();
      authStore.forceLogout();
      throw e;
    }
  }

  if (!response.ok) {
    let errorData;
    try {
      errorData = await response.json();
    } catch {
      errorData = {};
    }
    throw new Error(errorData.message || `HTTP Error: ${response.status}`);
  }

  const contentType = response.headers.get('content-type');
  if (contentType?.includes('application/json')) {
    try {
      return await response.json();
    } catch (e) {
      console.warn('Failed to parse JSON response', e);
      return null;
    }
  }

  return null;
}

export const apiClient = {
  get: (url) => request(url, { method: 'GET' }),
  post: (url, data) => request(url, {
    method: 'POST',
    body: JSON.stringify(data),
  }),
  put: (url, data) => request(url, {
    method: 'PUT',
    body: JSON.stringify(data),
  }),
  delete: (url) => request(url, { method: 'DELETE' }),
};