<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use RuntimeException;

class WeChatMiniProgramService
{
    /**
     * @return array{openid: string, unionid?: string, session_key: string}
     */
    public function codeToSession(string $code): array
    {
        $appId = config('services.wechat.mini_program.app_id');
        $secret = config('services.wechat.mini_program.secret');

        if (! $appId || ! $secret) {
            throw new RuntimeException('微信小程序 AppID/Secret 未配置');
        }

        $response = Http::timeout(10)->get('https://api.weixin.qq.com/sns/jscode2session', [
            'appid' => $appId,
            'secret' => $secret,
            'js_code' => $code,
            'grant_type' => 'authorization_code',
        ]);

        $payload = $response->json();
        if (! is_array($payload)) {
            throw new RuntimeException('微信登录响应异常');
        }

        if (! empty($payload['errcode'])) {
            throw new RuntimeException((string) ($payload['errmsg'] ?? '微信登录失败'));
        }

        if (empty($payload['openid'])) {
            throw new RuntimeException('微信登录未返回 openid');
        }

        return [
            'openid' => (string) $payload['openid'],
            'unionid' => isset($payload['unionid']) ? (string) $payload['unionid'] : null,
            'session_key' => (string) ($payload['session_key'] ?? ''),
        ];
    }
}