"""Hash data structures — fixed-length byte wrappers.

Ported from net.i2p.data.Hash, net.i2p.crypto.SHA1Hash, Hash384, Hash512.
"""

import hashlib


class Hash:
    """32-byte SHA-256 hash container."""

    HASH_LENGTH = 32

    __slots__ = ("_data", "_cached_hash")

    def __init__(self, data: bytes | None = None) -> None:
        if data is not None:
            if len(data) != self.HASH_LENGTH:
                raise ValueError(f"Hash data must be {self.HASH_LENGTH} bytes, got {len(data)}")
            self._data = bytes(data)
        else:
            self._data = b"\x00" * self.HASH_LENGTH
        self._cached_hash = int.from_bytes(self._data[:4], "big")

    @classmethod
    def create(cls, data: bytes, offset: int = 0) -> "Hash":
        return cls(data[offset : offset + cls.HASH_LENGTH])

    @property
    def data(self) -> bytes:
        return self._data

    def __eq__(self, other: object) -> bool:
        if isinstance(other, Hash):
            return self._data == other._data
        return NotImplemented

    def __hash__(self) -> int:
        return self._cached_hash

    def __repr__(self) -> str:
        return f"Hash({self._data.hex()})"

    def __bytes__(self) -> bytes:
        return self._data

    FAKE_HASH: "Hash"


Hash.FAKE_HASH = Hash(b"\x00" * Hash.HASH_LENGTH)


class SHA1Hash:
    """20-byte SHA-1 hash container."""

    HASH_LENGTH = 20

    __slots__ = ("_data", "_cached_hash")

    def __init__(self, data: bytes | None = None) -> None:
        if data is not None:
            if len(data) != self.HASH_LENGTH:
                raise ValueError(f"SHA1Hash data must be {self.HASH_LENGTH} bytes, got {len(data)}")
            self._data = bytes(data)
        else:
            self._data = b"\x00" * self.HASH_LENGTH
        self._cached_hash = int.from_bytes(self._data[:4], "big")

    @property
    def data(self) -> bytes:
        return self._data

    def __eq__(self, other: object) -> bool:
        if isinstance(other, SHA1Hash):
            return self._data == other._data
        return NotImplemented

    def __hash__(self) -> int:
        return self._cached_hash

    def __repr__(self) -> str:
        return f"SHA1Hash({self._data.hex()})"

    def __bytes__(self) -> bytes:
        return self._data


class Hash384:
    """48-byte hash container."""

    HASH_LENGTH = 48

    __slots__ = ("_data",)

    def __init__(self, data: bytes | None = None) -> None:
        if data is not None:
            if len(data) != self.HASH_LENGTH:
                raise ValueError(f"Hash384 data must be {self.HASH_LENGTH} bytes, got {len(data)}")
            self._data = bytes(data)
        else:
            self._data = b"\x00" * self.HASH_LENGTH

    @property
    def data(self) -> bytes:
        return self._data

    def __eq__(self, other: object) -> bool:
        if isinstance(other, Hash384):
            return self._data == other._data
        return NotImplemented

    def __hash__(self) -> int:
        return int.from_bytes(self._data[:4], "big")

    def __bytes__(self) -> bytes:
        return self._data


class Hash512:
    """64-byte hash container."""

    HASH_LENGTH = 64

    __slots__ = ("_data",)

    def __init__(self, data: bytes | None = None) -> None:
        if data is not None:
            if len(data) != self.HASH_LENGTH:
                raise ValueError(f"Hash512 data must be {self.HASH_LENGTH} bytes, got {len(data)}")
            self._data = bytes(data)
        else:
            self._data = b"\x00" * self.HASH_LENGTH

    @property
    def data(self) -> bytes:
        return self._data

    def __eq__(self, other: object) -> bool:
        if isinstance(other, Hash512):
            return self._data == other._data
        return NotImplemented

    def __hash__(self) -> int:
        return int.from_bytes(self._data[:4], "big")

    def __bytes__(self) -> bytes:
        return self._data