/**
 * arcrun auth_oauth2 Worker
 *
 * POST / → JSON input {action, api_key, service} → WASM (WASI preview1 stdin/stdout) → JSON output
 *
 * 額外 host functions（相較 auth_static_key）：
 *   - kv_put：快取 access_token（短效，TTL 跟隨 expires_in）
 *   - http_request：POST token endpoint 換 access_token
 */

import componentWasm from '../component.wasm' assert { type: 'webassembly' };
import { Hono } from 'hono';
import { cors } from 'hono/cors';
import {
  createWasiShim,
  createArcrunHostFunctions,
  type ArcrunHostEnv,
} from '../../../cypher-executor/src/lib/wasi-shim';

type Env = ArcrunHostEnv;

const app = new Hono<{ Bindings: Env }>();
app.use('*', cors());

app.get('/', (c) => c.json({ ok: true, component: 'auth_oauth2' }));

app.post('/', async (c) => {
  let input: Record<string, unknown>;
  try {
    input = await c.req.json();
  } catch {
    return c.json({ success: false, error: 'request body must be JSON' }, 400);
  }

  const apiKey = typeof input.api_key === 'string' ? input.api_key : '';
  if (!apiKey) {
    return c.json({ success: false, error: 'api_key 必填' }, 400);
  }

  try {
    const result = await runWasm(c.env, apiKey, input);
    return c.json(result);
  } catch (e) {
    return c.json(
      { success: false, error: e instanceof Error ? e.message : String(e) },
      500,
    );
  }
});

export default app;

// ── WASM runner ──────────────────────────────────────────────────────────────

async function runWasm(env: Env, apiKey: string, input: unknown): Promise<unknown> {
  const stdinData = JSON.stringify(input);
  const hostFunctions = createArcrunHostFunctions(env, apiKey);

  // 加入 http_request（token endpoint 用）
  hostFunctions.http_request = async (url, method, headersJSON, body) => {
    const headers: Record<string, string> = {};
    try {
      Object.assign(headers, JSON.parse(headersJSON || '{}'));
    } catch { /* ignore */ }

    const res = await fetch(url, {
      method,
      headers,
      body: body || undefined,
    });
    return res.text();
  };

  const shim = createWasiShim(stdinData, hostFunctions);

  const instance = await WebAssembly.instantiate(
    componentWasm as WebAssembly.Module,
    shim.imports,
  );
  shim.setMemory(instance.exports.memory as WebAssembly.Memory);
  await shim.run(instance);

  const stdout = shim.getStdout().trim();
  if (!stdout) throw new Error('WASM component produced no output');
  return JSON.parse(stdout);
}
