frontend/src/api.js

// src/api.js

const configuredApiUrl = (import.meta.env.VITE_API_URL || '').trim();
const isLocalhost = typeof window !== 'undefined' && ['localhost', '127.0.0.1'].includes(window.location.hostname);
const defaultApiUrl = isLocalhost ? 'http://localhost:4000/api' : '/api';
const API_URL = (configuredApiUrl || defaultApiUrl).replace(/\/$/, '');

const getHeaders = (options = {}) => {
  const headers = {
    ...options.headers,
  };

  // Add auth token if exists
  const token = localStorage.getItem('token');
  if (token) {
    headers['Authorization'] = `Bearer ${token}`;
  }

  // Only add Content-Type if we're not sending FormData
  if (!(options.body instanceof FormData)) {
    headers['Content-Type'] = 'application/json';
  }

  return headers;
};

export const fetchApi = async (endpoint, options = {}) => {
  try {
    const url = `${API_URL}${endpoint.startsWith('/') ? endpoint : `/${endpoint}`}`;

    // Default fetch options
    const fetchOptions = {
      ...options,
      headers: getHeaders(options),
    };

    // Stringify body if it's an object (and not FormData)
    if (options.body && typeof options.body === 'object' && !(options.body instanceof FormData)) {
      fetchOptions.body = JSON.stringify(options.body);
    }

    const response = await fetch(url, fetchOptions);

    let data;
    const contentType = response.headers.get("content-type");
    if (contentType && contentType.indexOf("application/json") !== -1) {
      data = await response.json();
    } else {
      data = await response.text();
    }

    if (!response.ok) {
      const errorMessage = data?.error || data?.message || data || 'An error occurred';
      throw new Error(errorMessage);
    }

    return data;
  } catch (error) {
    console.error(`API Error (${endpoint}):`, error);
    throw error;
  }
};

export const streamApi = async (endpoint, options = {}, onToken) => {
  const url = `${API_URL}${endpoint.startsWith('/') ? endpoint : `/${endpoint}`}`;
  const fetchOptions = {
    ...options,
    headers: getHeaders(options),
  };

  if (options.body && typeof options.body === 'object' && !(options.body instanceof FormData)) {
    fetchOptions.body = JSON.stringify(options.body);
  }

  const response = await fetch(url, fetchOptions);
  if (!response.ok) {
    const data = await response.json().catch(() => ({}));
    throw new Error(data.error || 'Stream error');
  }

  const reader = response.body.getReader();
  const decoder = new TextDecoder();
  let done = false;

  while (!done) {
    const { value, done: doneReading } = await reader.read();
    done = doneReading;
    const chunkValue = decoder.decode(value);
    if (chunkValue) {
      onToken(chunkValue);
    }
  }
};