import { Platform } from 'react-native';
import {
    retrieveVerificationCode,
    startSmsHandling,
} from '@eabdullazyanov/react-native-sms-user-consent';

/** 用户点允许后，从短信正文取数字（优先 preferLength 位，否则取第一段数字） */
export function digitsFromSms(message: string, preferLength?: number): string {
    if (preferLength) {
        const exact = retrieveVerificationCode(message, preferLength);
        if (exact) return exact;
    }
    const m = message.match(/\d+/);
    return m ? m[0] : '';
}

/**
 * SMS User Consent：系统弹窗，用户同意后才回调；无需 READ_SMS / app hash。
 */
export function startSmsUserConsentListener(
    preferLength: number,
    onDigits: (digits: string) => void,
): () => void {
    if (Platform.OS !== 'android') return () => {};

    return startSmsHandling((event) => {
        const sms = event?.sms ?? '';
        if (!sms) return;
        const digits = digitsFromSms(sms, preferLength);
        if (digits) onDigits(digits);
    });
}