"""
独立的CRT提取测试 - 不依赖大型模块
"""
import pikepdf
from cryptography.hazmat.primitives.serialization.pkcs7 import load_der_pkcs7_certificates
from cryptography.x509.oid import NameOID
import re

def _get_name_attr(name, oid: NameOID):
    """Extract attribute value from X.500 name by OID."""
    try:
        values = name.get_attributes_for_oid(oid)
    except ValueError:
        return None
    return values[0].value if values else None

def parse_certificates_improved(signature_bytes: bytes) -> list:
    """
    改进的证书解析函数，添加binary search fallback
    """
    candidates = []

    # Method 1: Try PKCS#7 parsing first
    try:
        certs = load_der_pkcs7_certificates(signature_bytes)

        # Usually first cert in bundle is signer's cert
        for cert in certs:
            # Collect potential organization names from CN, O, OU
            def add_if_valid(oid):
                val = _get_name_attr(cert.subject, oid)
                if val:
                    clean = val.strip()
                    if len(clean) >= 4 and clean not in candidates:
                        candidates.append(clean)

            add_if_valid(NameOID.COMMON_NAME)
            add_if_valid(NameOID.ORGANIZATION_NAME)
            add_if_valid(NameOID.ORGANIZATIONAL_UNIT_NAME)

    except Exception as e:
        print(f"    PKCS#7 parsing failed: {e}")

    # Method 2: Fallback - search for known institution names in binary data
    if not candidates:
        print(f"    No candidates from PKCS#7, trying binary search fallback...")

        known_institutions = [
            "广东产品质量监督检验研究院",
            "广东产品质量监督检验",
            "广东省产品质量监督检验研究院",
            "质量监督检验研究院",
        ]

        for inst in known_institutions:
            encoded = inst.encode('utf-8')
            if encoded in signature_bytes:
                if inst not in candidates:
                    candidates.append(inst)
                    print(f"    Found in binary data: {inst}")

        # Also try pattern matching
        try:
            decoded = signature_bytes.decode('utf-8', errors='ignore')
            patterns = [
                r'[\u4e00-\u9fff]{4,}(?:研究院|研究所|检测中心|检验院)',
                r'[\u4e00-\u9fff]{4,}(?:有限公司)',
            ]

            for pattern in patterns:
                matches = re.findall(pattern, decoded)
                for match in matches:
                    if len(match) >= 4 and match not in candidates:
                        candidates.append(match)
                        print(f"    Found pattern: {match}")

        except Exception as e:
            print(f"    Pattern matching failed: {e}")

    return candidates

def extract_institution_from_crt_improved(pdf_path: str) -> list:
    """改进的CRT提取函数"""
    try:
        pdf = pikepdf.Pdf.open(pdf_path)
    except Exception as e:
        print(f"Failed to open PDF: {e}")
        return []

    try:
        acroform = pdf.Root.get("/AcroForm")
        if not acroform:
            print("No /AcroForm found")
            return []

        fields = acroform.get("/Fields", [])
        all_candidates = []

        for idx, field in enumerate(fields):
            field_obj = field
            if field_obj.get("/FT") != "/Sig":
                continue

            sig_dict = field_obj.get("/V")
            if not sig_dict:
                continue

            contents_obj = sig_dict.get("/Contents")
            if contents_obj is None:
                continue

            contents = bytes(contents_obj)
            print(f"\n  Signature #{idx}:")
            print(f"    Size: {len(contents)} bytes")

            candidates = parse_certificates_improved(contents)
            for candidate in candidates:
                if candidate not in all_candidates:
                    all_candidates.append(candidate)

            if len(all_candidates) > 0 and idx >= 2:  # Found candidates and checked 3 signatures
                break

        return all_candidates

    except Exception as e:
        print(f"Error: {e}")
        import traceback
        traceback.print_exc()
        return []

def main():
    test_pdfs = [
        ("src/test/resources/data/pdfs/YDQ25_002294.pdf", "广东产品质量监督检验研究院"),
        ("src/test/resources/data/pdfs/YDQ23_001838.pdf", "广东产品质量监督检验研究院"),
    ]

    print("="*80)
    print("STANDALONE CRT EXTRACTION TEST")
    print("="*80)

    for pdf_path, expected in test_pdfs:
        print(f"\n{'#'*80}")
        print(f"Testing: {pdf_path}")
        print(f"Expected: {expected}")
        print(f"{'#'*80}")

        result = extract_institution_from_crt_improved(pdf_path)

        print(f"\nResult: {result}")

        if expected in result:
            print(f"✓✓✓ SUCCESS! Found expected institution")
        elif result:
            print(f"⚠ PARTIAL SUCCESS! Found institutions but not expected:")
            print(f"   Expected: {expected}")
            print(f"   Got: {result}")
        else:
            print(f"✗✗✗ FAILED! No institutions extracted")

    print("\n" + "="*80)

if __name__ == "__main__":
    main()