const rs = require('jsrsasign');

// 用户提供的 SM2 PKCS7 签名数据
const sm2P7Base64 = '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';

const parser = new rs.KJUR.asn1.cms.CMSParser();
const p7 = parser.getCMSSignedData(rs.b64tohex(sm2P7Base64));

console.log('=== 调试 SM2 公钥提取 ===');

if (p7.certs && p7.certs.array && p7.certs.array.length > 0) {
    const certPem = p7.certs.array[0];
    
    // 将 PEM 转换为 hex
    const certHex = rs.pemtohex(certPem);
    console.log('证书 hex 长度:', certHex.length);
    console.log('证书 hex 前100字符:', certHex.substring(0, 100));
    
    // 证书结构: SEQUENCE { tbsCertificate, signatureAlgorithm, signatureValue }
    // tbsCertificate 结构: SEQUENCE { version, serialNumber, signature, issuer, validity, subject, subjectPublicKeyInfo, ... }
    
    try {
        // 获取 tbsCertificate
        const tbsCert = rs.ASN1HEX.getTLVbyList(certHex, 0, [0]);
        console.log('\ntbsCertificate 长度:', tbsCert.length);
        
        // 获取 subjectPublicKeyInfo (在 tbsCertificate 中的索引通常是 6)
        // 但我们需要先确定正确的索引
        let spkiIndex = 6;
        let spki = null;
        
        // 尝试不同的索引
        for (let i = 3; i <= 8; i++) {
            try {
                const tlv = rs.ASN1HEX.getTLVbyList(tbsCert, 0, [i]);
                if (tlv && tlv.startsWith('30')) { // SEQUENCE
                    // 检查是否是 subjectPublicKeyInfo
                    // subjectPublicKeyInfo 应该包含 algorithm 和 subjectPublicKey
                    const inner = rs.ASN1HEX.getTLVbyList(tlv, 0, [0]);
                    if (inner && inner.startsWith('30')) {
                        console.log(`索引 ${i} 可能是 subjectPublicKeyInfo`);
                        spki = tlv;
                        spkiIndex = i;
                        break;
                    }
                }
            } catch (e) {
                // 忽略错误
            }
        }
        
        if (spki) {
            console.log('\nsubjectPublicKeyInfo hex:', spki.substring(0, 100));
            
            // 提取算法 OID
            try {
                const algorithmSeq = rs.ASN1HEX.getTLVbyList(spki, 0, [0]);
                console.log('algorithmSeq:', algorithmSeq);
                
                // 提取 OID
                const oidTlv = rs.ASN1HEX.getTLVbyList(algorithmSeq, 0, [0]);
                console.log('OID TLV:', oidTlv);
                
                // 解析 OID
                if (oidTlv && oidTlv.startsWith('06')) {
                    const oidHex = oidTlv.substring(4);
                    console.log('OID hex:', oidHex);
                }
            } catch (e) {
                console.error('提取算法 OID 错误:', e.message);
            }
            
            // 提取公钥值 (BIT STRING)
            try {
                const publicKeyBitString = rs.ASN1HEX.getTLVbyList(spki, 0, [1]);
                console.log('\n公钥 BIT STRING:', publicKeyBitString.substring(0, 100));
                
                // BIT STRING 的内容从第4个字符开始 (跳过 tag 03, length, 和 unused bits 00)
                const publicKeyContent = publicKeyBitString.substring(4);
                console.log('公钥内容:', publicKeyContent.substring(0, 100));
                
                // 对于 SM2，公钥通常是 65 字节 (0x04 + 32字节 X + 32字节 Y)
                console.log('公钥内容长度:', publicKeyContent.length / 2, '字节');
                
                // 创建公钥 hex
                console.log('\n公钥 hex (完整):', publicKeyContent);
            } catch (e) {
                console.error('提取公钥值错误:', e.message);
            }
        }
    } catch (e) {
        console.error('ASN.1 解析错误:', e.message);
        console.error(e.stack);
    }
}