// In production (embedded in Go binary), the frontend is served from the same origin as the API.
// In dev mode, Next.js runs on :3000 and Go on :3721, so we need explicit addresses.
// When deployed to cloud (e.g. AWS), the user can set a custom backend URL in Settings.
const isDev = process.env.NODE_ENV === 'development';

const BACKEND_URL_STORAGE_KEY = 'edge-ai-backend-url';
const RELAY_TOKEN_STORAGE_KEY = 'edge-ai-relay-token';

function getStoredBackendUrl(): string {
  if (typeof window === 'undefined') return '';
  return localStorage.getItem(BACKEND_URL_STORAGE_KEY) || '';
}

export function setBackendUrl(url: string): void {
  if (typeof window === 'undefined') return;
  if (url) {
    localStorage.setItem(BACKEND_URL_STORAGE_KEY, url.replace(/\/+$/, ''));
  } else {
    localStorage.removeItem(BACKEND_URL_STORAGE_KEY);
  }
}

export function getBackendUrl(): string {
  if (isDev) return 'http://localhost:3721';
  return getStoredBackendUrl();
}

export function getApiBaseUrl(): string {
  // In dev mode, use relative path so Next.js rewrite proxy handles it
  if (isDev) return '/api';
  const backend = getStoredBackendUrl();
  return backend ? `${backend}/api` : '/api';
}

export function getWsBaseUrl(): string {
  if (typeof window === 'undefined') return '';
  if (isDev) return 'ws://localhost:3721';
  const backend = getStoredBackendUrl();
  if (backend) {
    return backend.replace(/^http/, 'ws');
  }
  const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
  return `${protocol}//${window.location.host}`;
}

// --- Relay Token ---

export function getRelayToken(): string {
  if (typeof window === 'undefined') return '';
  return localStorage.getItem(RELAY_TOKEN_STORAGE_KEY) || '';
}

export function setRelayToken(token: string): void {
  if (typeof window === 'undefined') return;
  if (token) {
    localStorage.setItem(RELAY_TOKEN_STORAGE_KEY, token);
  } else {
    localStorage.removeItem(RELAY_TOKEN_STORAGE_KEY);
  }
}

// Check URL query params for a relay token (e.g. ?token=abc123).
// If found, cache it in localStorage and remove the param from the URL.
// This is the primary mechanism: local server opens the browser with the
// token embedded in the URL, so no cross-origin fetch is needed.
export function syncRelayTokenFromURL(): string {
  if (typeof window === 'undefined') return '';
  const params = new URLSearchParams(window.location.search);
  const token = params.get('token');
  if (token) {
    setRelayToken(token);
    // Clean up URL — remove token param without reload
    params.delete('token');
    const newSearch = params.toString();
    const newUrl = window.location.pathname + (newSearch ? `?${newSearch}` : '') + window.location.hash;
    window.history.replaceState({}, '', newUrl);
    return token;
  }
  return getRelayToken();
}

// Kept for backward compatibility — now simply returns cached token.
export async function fetchAndCacheRelayToken(): Promise<string> {
  return syncRelayTokenFromURL();
}

// Append relay token as query parameter to a URL. Used for resources loaded
// via <img src> or other HTML elements that cannot send custom headers.
export function appendRelayToken(url: string): string {
  const token = getRelayToken();
  if (!token) return url;
  const sep = url.includes('?') ? '&' : '?';
  return `${url}${sep}token=${encodeURIComponent(token)}`;
}

export const ROUTES = {
  HOME: '/',
  MODELS: '/models',
  MODEL_DETAIL: (id: string) => `/models/${id}`,
  DEVICES: '/devices',
  DEVICE_DETAIL: (id: string) => `/devices/${id}`,
  WORKSPACE: (deviceId: string) => `/workspace/${deviceId}`,
} as const;

export const TASK_TYPES = {
  object_detection: 'Object Detection',
  classification: 'Classification',
} as const;

export const HARDWARE_OPTIONS = ['KL520', 'KL720', 'KL730'] as const;