"""Chaintracks filesystem utilities.

Provides filesystem operations for chaintracks data management.

Reference: wallet-toolbox/src/services/chaintracker/chaintracks/util/ChaintracksFs.ts
"""

import os
from typing import Any


class ChaintracksFs:
    """Filesystem utilities for chaintracks.

    Provides path manipulation and file I/O operations.

    Reference: wallet-toolbox/src/services/chaintracker/chaintracks/util/ChaintracksFs.ts
    """

    @staticmethod
    def path_join(*parts: str) -> str:
        """Join path components.

        Args:
            *parts: Path components to join

        Returns:
            Joined path
        """
        return os.path.join(*parts)

    @staticmethod
    async def read_file(path: str) -> bytes:
        """Read file contents.

        Args:
            path: Path to file

        Returns:
            File contents as bytes

        Raises:
            FileNotFoundError: If file doesn't exist
        """
        with open(path, "rb") as f:
            return f.read()

    @staticmethod
    async def write_file(path: str, data: bytes) -> None:
        """Write file contents.

        Args:
            path: Path to file
            data: Data to write
        """
        with open(path, "wb") as f:
            f.write(data)

    @staticmethod
    async def file_exists(path: str) -> bool:
        """Check if file exists.

        Args:
            path: Path to check

        Returns:
            True if file exists
        """
        return os.path.exists(path)

    @staticmethod
    async def mkdir(path: str, recursive: bool = True) -> None:
        """Create directory.

        Args:
            path: Directory path
            recursive: Create parent directories if needed
        """
        if recursive:
            os.makedirs(path, exist_ok=True)
        else:
            os.mkdir(path)


def deserialize_block_headers(start_height: int, data: bytes) -> list[dict[str, Any]]:
    """Deserialize block headers from binary data.

    Args:
        start_height: Starting block height
        data: Binary header data

    Returns:
        List of deserialized headers

    Reference: wallet-toolbox/src/services/chaintracker/chaintracks/util/BulkFileDataManager.ts
               deserializeBlockHeaders()
    """
    # Stub implementation - in production would parse actual header format
    # Block headers are 80 bytes each
    header_size = 80
    num_headers = len(data) // header_size

    headers = []
    for i in range(num_headers):
        offset = i * header_size
        header_bytes = data[offset : offset + header_size]
        headers.append(
            {
                "height": start_height + i,
                "data": header_bytes,
                # Additional fields would be parsed from header_bytes
            }
        )

    return headers
