import type { AssistantBridge, BrowserStateEvent, RevealEvent, ViewMode, ViewportMessage } from '../electron/shared';

declare global {
  interface Window {
    assistant?: AssistantBridge;
  }
}

// 没有 Electron（在普通浏览器里调试界面）时退回到直接请求后端
const FALLBACK_PORT = 8788;
const FALLBACK_BASE = `http://127.0.0.1:${FALLBACK_PORT}/api`;

async function fetchJson<T>(method: string, path: string, body?: unknown): Promise<T> {
  const response = await fetch(FALLBACK_BASE + path, {
    method,
    headers: { 'Content-Type': 'application/json' },
    body: body === undefined ? undefined : JSON.stringify(body),
  });
  const data = (await response.json().catch(() => ({}))) as Record<string, unknown>;
  if (!response.ok) {
    const detail = typeof data.detail === 'string' ? data.detail : response.statusText;
    throw new Error(detail);
  }
  return data as T;
}

const noop = (): (() => void) => () => undefined;

const fallback: AssistantBridge = {
  get: path => fetchJson('GET', path),
  post: (path, body) => fetchJson('POST', path, body ?? {}),
  put: (path, body) => fetchJson('PUT', path, body ?? {}),
  del: path => fetchJson('DELETE', path),
  openPath: async () => '当前为浏览器预览，请在桌面端打开本地文件。',
  meta: async () => ({ apiPort: FALLBACK_PORT, cdpPort: 0, controlPort: 0, version: 'browser-dev' }),
  browser: {
    viewport: async () => undefined,
    mode: async () => undefined,
    onState: noop,
    onReveal: noop,
    onHide: noop,
    onUserInput: noop,
  },
};

const bridge: AssistantBridge = window.assistant ?? fallback;

export const isElectron = Boolean(window.assistant);

export const api = {
  get: <T>(path: string): Promise<T> => bridge.get(path) as Promise<T>,
  post: <T>(path: string, body?: unknown): Promise<T> => bridge.post(path, body) as Promise<T>,
  put: <T>(path: string, body?: unknown): Promise<T> => bridge.put(path, body) as Promise<T>,
  del: <T>(path: string): Promise<T> => bridge.del(path) as Promise<T>,
  openPath: (filePath: string): Promise<string> => bridge.openPath(filePath),
  appMeta: () => bridge.meta(),
  browser: {
    viewport: (message: ViewportMessage): Promise<void> => bridge.browser.viewport(message),
    mode: (taskId: string, mode: ViewMode): Promise<void> => bridge.browser.mode(taskId, mode),
    onState: (handler: (event: BrowserStateEvent) => void): (() => void) => bridge.browser.onState(handler),
    onReveal: (handler: (event: RevealEvent) => void): (() => void) => bridge.browser.onReveal(handler),
    onHide: (handler: (event: RevealEvent) => void): (() => void) => bridge.browser.onHide(handler),
    onUserInput: (handler: (event: RevealEvent) => void): (() => void) => bridge.browser.onUserInput(handler),
  },
};

export function errorText(error: unknown): string {
  return error instanceof Error ? error.message : String(error);
}