synta 0.2.0

#!/usr/bin/env python3
"""
Basic example of using Synta Python bindings

This example demonstrates:
- Decoding ASN.1 data
- Encoding ASN.1 data
- Working with various ASN.1 types
- Parsing X.509 certificates
"""

import base64
import synta
import synta.oids as oids


def example_integers():
    """Example: Working with INTEGERs"""
    print("\n" + "=" * 60)
    print("Example 1: Working with INTEGERs")
    print("=" * 60)

    # Decode an integer
    data = b'\x02\x01\x2A'  # DER-encoded INTEGER 42
    decoder = synta.Decoder(data, synta.Encoding.DER)
    integer = decoder.decode_integer()
    print(f"Decoded INTEGER: {integer.to_int()}")

    # Encode an integer
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_integer(100)
    encoded = encoder.finish()
    print(f"Encoded INTEGER 100: {encoded.hex()}")


def example_oids():
    """Example: Working with Object Identifiers"""
    print("\n" + "=" * 60)
    print("Example 2: Working with Object Identifiers")
    print("=" * 60)

    # Create OID from constant (RSA encryption)
    oid = oids.RSA_ENCRYPTION
    print(f"RSA Encryption OID: {oid}")
    print(f"Components: {oid.components()}")

    # Encode the OID
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_oid(oid)
    encoded = encoder.finish()
    print(f"Encoded: {encoded.hex()}")

    # Decode it back
    decoder = synta.Decoder(encoded, synta.Encoding.DER)
    decoded_oid = decoder.decode_oid()
    print(f"Decoded back: {decoded_oid}")


def example_octet_strings():
    """Example: Working with OCTET STRINGs"""
    print("\n" + "=" * 60)
    print("Example 3: Working with OCTET STRINGs")
    print("=" * 60)

    # Create and encode an octet string
    message = b"Hello, ASN.1!"
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_octet_string(message)
    encoded = encoder.finish()
    print(f"Encoded message: {encoded.hex()}")

    # Decode it back
    decoder = synta.Decoder(encoded, synta.Encoding.DER)
    octet_string = decoder.decode_octet_string()
    decoded_message = octet_string.to_bytes()
    print(f"Decoded message: {decoded_message.decode('utf-8')}")


def example_multiple_values():
    """Example: Encoding and decoding multiple values"""
    print("\n" + "=" * 60)
    print("Example 4: Multiple values in sequence")
    print("=" * 60)

    # Encode multiple values
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_integer(42)
    encoder.encode_boolean(True)
    encoder.encode_octet_string(b"test")
    encoded = encoder.finish()

    print(f"Encoded sequence: {encoded.hex()}")
    print(f"Total length: {len(encoded)} bytes")

    # Decode them back
    decoder = synta.Decoder(encoded, synta.Encoding.DER)

    integer = decoder.decode_integer()
    print(f"  1. INTEGER: {integer.to_int()}")

    boolean = decoder.decode_boolean()
    print(f"  2. BOOLEAN: {boolean.value()}")

    octet_string = decoder.decode_octet_string()
    print(f"  3. OCTET STRING: {octet_string.to_bytes()}")

    print(f"Remaining bytes: {decoder.remaining()}")


def example_string_types():
    """Example: Working with ASN.1 string types"""
    print("\n" + "=" * 60)
    print("Example 5: ASN.1 String Types")
    print("=" * 60)

    # UTF8String
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_utf8_string("Hello, World!")
    encoded = encoder.finish()
    decoder = synta.Decoder(encoded, synta.Encoding.DER)
    s = decoder.decode_utf8_string()
    print(f"UTF8String round-trip: {s.as_str()!r}")

    # PrintableString (A-Z, a-z, digits, and ' ( ) + , - . / : = ?)
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_printable_string("Example Corp")
    encoded = encoder.finish()
    decoder = synta.Decoder(encoded, synta.Encoding.DER)
    s = decoder.decode_printable_string()
    print(f"PrintableString round-trip: {s.as_str()!r}")

    # IA5String (ASCII)
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_ia5_string("user@example.com")
    encoded = encoder.finish()
    decoder = synta.Decoder(encoded, synta.Encoding.DER)
    s = decoder.decode_ia5_string()
    print(f"IA5String round-trip: {s.as_str()!r}")


def example_null():
    """Example: Working with ASN.1 NULL"""
    print("\n" + "=" * 60)
    print("Example 6: ASN.1 NULL")
    print("=" * 60)

    # Encode NULL
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_null()
    encoded = encoder.finish()
    print(f"Encoded NULL: {encoded.hex()}")  # Output: 0500

    # Decode NULL
    decoder = synta.Decoder(encoded, synta.Encoding.DER)
    null = decoder.decode_null()
    print(f"Decoded: {null!r}")


def example_real():
    """Example: Working with ASN.1 REAL (IEEE 754 floating point)"""
    import math
    print("\n" + "=" * 60)
    print("Example 7: ASN.1 REAL")
    print("=" * 60)

    # Zero encodes as a zero-length value (tag + length only)
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_real(0.0)
    data = encoder.finish()
    print(f"Encoded 0.0:      {data.hex()}")  # Output: 0900

    # Special values use a one-byte content
    for name, value in [("math.inf", math.inf), ("-math.inf", -math.inf), ("math.nan", math.nan)]:
        encoder = synta.Encoder(synta.Encoding.DER)
        encoder.encode_real(value)
        data = encoder.finish()
        print(f"Encoded {name:12} {data.hex()}")

    # Round-trip a finite value
    pi = 3.141592653589793
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_real(pi)
    encoded = encoder.finish()
    decoder = synta.Decoder(encoded, synta.Encoding.DER)
    r = decoder.decode_real()
    print(f"Round-trip π:     {r.value()}")

    # Construct directly and test helpers
    r_inf = synta.Real(math.inf)
    print(f"is_infinite:      {r_inf.is_infinite()}")
    print(f"is_finite:        {synta.Real(1.5).is_finite()}")
    print(f"float() cast:     {float(synta.Real(2.5))}")

    # encode_real_object accepts a Real object
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_real_object(synta.Real(1.0))
    data = encoder.finish()
    decoder = synta.Decoder(data, synta.Encoding.DER)
    assert decoder.decode_real().value() == 1.0
    print("encode_real_object round-trip: OK")


def example_decode_any():
    """Example: Dynamic decoding with decode_any"""
    print("\n" + "=" * 60)
    print("Example 8: decode_any — dynamic element parsing")
    print("=" * 60)

    # SEQUENCE { INTEGER 1, BOOLEAN TRUE }
    # 30 06 02 01 01 01 01 ff
    data = b'\x30\x06\x02\x01\x01\x01\x01\xff'
    decoder = synta.Decoder(data, synta.Encoding.DER)
    seq = decoder.decode_any()
    print(f"Decoded SEQUENCE: {seq}")
    print(f"  Element 0: {seq[0]!r}  (type: {type(seq[0]).__name__})")
    print(f"  Element 1: {seq[1]!r}  (type: {type(seq[1]).__name__})")

    # Individual primitives
    for raw in [b'\x02\x01\x2A', b'\x01\x01\xff', b'\x05\x00']:
        decoder = synta.Decoder(raw, synta.Encoding.DER)
        obj = decoder.decode_any()
        print(f"  {raw.hex()} → {obj!r}")


# Self-signed RSA certificate for the certificate example
_EXAMPLE_CERT_PEM = """\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"""


def example_certificate():
    """Example: Parsing an X.509 certificate"""
    print("\n" + "=" * 60)
    print("Example 9: X.509 Certificate Parsing")
    print("=" * 60)

    der = base64.b64decode(_EXAMPLE_CERT_PEM)
    cert = synta.Certificate.from_der(der)

    print(f"Subject:             {cert.subject}")
    print(f"Issuer:              {cert.issuer}")
    print(f"Version:             v{(cert.version or 0) + 1}")
    print(f"Serial number:       {cert.serial_number}")
    print(f"Not before:          {cert.not_before}")
    print(f"Not after:           {cert.not_after}")
    print(f"Signature algorithm: {cert.signature_algorithm}")
    print(f"Public key alg:      {cert.public_key_algorithm}")
    print(f"Public key length:   {len(cert.public_key)} bytes")


def example_common_oids():
    """Example: Common OIDs used in cryptography"""
    print("\n" + "=" * 60)
    print("Example 10: Common Cryptographic OIDs")
    print("=" * 60)

    common_oids = {
        "RSA Encryption":    oids.RSA_ENCRYPTION,
        "SHA-256":           oids.SHA256,
        "EC Public Key":     oids.EC_PUBLIC_KEY,
        "secp256r1 (P-256)": oids.EC_CURVE_P256,
        "Ed25519":           oids.ED25519,
    }

    for name, oid in common_oids.items():
        encoder = synta.Encoder(synta.Encoding.DER)
        encoder.encode_oid(oid)
        encoded = encoder.finish()
        print(f"{name:20} {str(oid):30} ({len(encoded)} bytes)")


def example_bit_string():
    """Example: Working with ASN.1 BIT STRINGs"""
    print("\n" + "=" * 60)
    print("Example 11: ASN.1 BIT STRING")
    print("=" * 60)

    # Construct a BIT STRING: value 0xff 0x00, 0 unused bits → 16 significant bits
    bs = synta.BitString(b'\xff\x00', 0)
    print(f"Bit length:    {bs.bit_len()}")
    print(f"Unused bits:   {bs.unused_bits()}")
    print(f"Bytes:         {bs.to_bytes().hex()}")

    # Encode and check the DER output
    encoder = synta.Encoder(synta.Encoding.DER)
    encoder.encode_bit_string(bs)
    encoded = encoder.finish()
    # DER: 03 03 00 ff 00 — tag, length, unused-bits, data
    print(f"DER encoding:  {encoded.hex()}")

    # Decode it back
    decoder = synta.Decoder(encoded, synta.Encoding.DER)
    decoded = decoder.decode_bit_string()
    print(f"Round-trip OK: {decoded.to_bytes().hex() == 'ff00'}")

    # With unused bits: a 13-bit value (last 3 bits of 0x80 are padding)
    bs2 = synta.BitString(b'\xff\x80', 3)
    encoder2 = synta.Encoder(synta.Encoding.DER)
    encoder2.encode_bit_string(bs2)
    encoded2 = encoder2.finish()
    print(f"13-bit value:  {encoded2.hex()}  ({bs2.bit_len()} bits)")


def example_additional_string_types():
    """Example: NumericString, TeletexString, VisibleString, GeneralString,
    UniversalString, and BMPString"""
    print("\n" + "=" * 60)
    print("Example 12: Additional ASN.1 String Types")
    print("=" * 60)

    # NumericString — only digits and spaces (tag 18 / 0x12)
    enc = synta.Encoder(synta.Encoding.DER)
    enc.encode_numeric_string("12345 67890")
    data = enc.finish()
    s = synta.Decoder(data, synta.Encoding.DER).decode_numeric_string()
    print(f"NumericString:    {s.as_str()!r}  (tag {data[0]:#04x})")

    # TeletexString / T61String — arbitrary bytes, used in legacy X.509 subjects (tag 20 / 0x14)
    enc = synta.Encoder(synta.Encoding.DER)
    enc.encode_teletex_string(b"Legacy Corp")
    data = enc.finish()
    s = synta.Decoder(data, synta.Encoding.DER).decode_teletex_string()
    print(f"TeletexString:    {s.to_bytes()!r}  (tag {data[0]:#04x})")

    # VisibleString — printable ASCII excluding space (tag 26 / 0x1a)
    enc = synta.Encoder(synta.Encoding.DER)
    enc.encode_visible_string("Hello,World!")
    data = enc.finish()
    s = synta.Decoder(data, synta.Encoding.DER).decode_visible_string()
    print(f"VisibleString:    {s.as_str()!r}  (tag {data[0]:#04x})")

    # GeneralString — used in Kerberos realms and principal names (tag 27 / 0x1b)
    enc = synta.Encoder(synta.Encoding.DER)
    enc.encode_general_string(b"EXAMPLE.COM")
    data = enc.finish()
    s = synta.Decoder(data, synta.Encoding.DER).decode_general_string()
    print(f"GeneralString:    {s.to_bytes()!r}  (tag {data[0]:#04x})")

    # UniversalString — UCS-4 encoding, 4 bytes per character (tag 28 / 0x1c)
    enc = synta.Encoder(synta.Encoding.DER)
    enc.encode_universal_string("Hi")
    data = enc.finish()
    s = synta.Decoder(data, synta.Encoding.DER).decode_universal_string()
    print(f"UniversalString:  {s.as_str()!r}  (tag {data[0]:#04x}, {len(data)-2} content bytes)")

    # BMPString — UCS-2 encoding, 2 bytes per character; BMP plane only (tag 30 / 0x1e)
    enc = synta.Encoder(synta.Encoding.DER)
    enc.encode_bmp_string("café")
    data = enc.finish()
    s = synta.Decoder(data, synta.Encoding.DER).decode_bmp_string()
    print(f"BMPString:        {s.as_str()!r}  (tag {data[0]:#04x}, {len(data)-2} content bytes)")


def example_structured_types():
    """Example: SEQUENCE, SET, EXPLICIT TAG, and RawElement"""
    print("\n" + "=" * 60)
    print("Example 13: Structured types and unknown tags")
    print("=" * 60)

    # Build a SEQUENCE containing INTEGER 42 and BOOLEAN TRUE
    inner = synta.Encoder(synta.Encoding.DER)
    inner.encode_integer(42)
    inner.encode_boolean(True)
    inner_bytes = inner.finish()

    outer = synta.Encoder(synta.Encoding.DER)
    outer.encode_sequence(inner_bytes)
    seq_encoded = outer.finish()
    print(f"SEQUENCE {{{inner_bytes.hex()}}}: {seq_encoded.hex()}")

    # Decode the SEQUENCE — decode_sequence returns a child Decoder
    decoder = synta.Decoder(seq_encoded, synta.Encoding.DER)
    child = decoder.decode_sequence()
    n = child.decode_integer()
    b = child.decode_boolean()
    print(f"  Decoded: INTEGER={n.to_int()}, BOOLEAN={b.value()}")

    # EXPLICIT TAG wrapping: [1] EXPLICIT INTEGER 99
    inner2 = synta.Encoder(synta.Encoding.DER)
    inner2.encode_integer(99)
    tagged_encoded = synta.Encoder(synta.Encoding.DER)
    tagged_encoded.encode_explicit_tag(1, "Context", inner2.finish())
    tagged_bytes = tagged_encoded.finish()
    print(f"[1] EXPLICIT INTEGER 99: {tagged_bytes.hex()}")

    decoder2 = synta.Decoder(tagged_bytes, synta.Encoding.DER)
    child2 = decoder2.decode_explicit_tag(1)
    print(f"  Decoded: INTEGER={child2.decode_integer().to_int()}")

    # RawElement — decode_any returns RawElement for tags synta doesn't know
    # Tag 25 (0x19) = ObjectDescriptor — not implemented
    raw_tlv = bytes([0x19, 0x03, ord('a'), ord('b'), ord('c')])
    val = synta.Decoder(raw_tlv, synta.Encoding.DER).decode_any()
    print(f"Unknown tag 25: {type(val).__name__}"
          f"  tag={val.tag_number}, class={val.tag_class}"
          f", data={val.data!r}")


def main():
    """Run all examples"""
    print("=" * 60)
    print("Synta Python Bindings - Examples")
    print("=" * 60)

    example_integers()
    example_oids()
    example_octet_strings()
    example_multiple_values()
    example_string_types()
    example_null()
    example_real()
    example_decode_any()
    example_certificate()
    example_common_oids()
    example_bit_string()
    example_additional_string_types()
    example_structured_types()

    print("\n" + "=" * 60)
    print("Examples completed successfully!")
    print("=" * 60)


if __name__ == '__main__':
    main()