compression

"""
File compression utilities using gzip.
"""

import gzip
import shutil
from pathlib import Path
from typing import Optional
import logging

logger = logging.getLogger(__name__)


def compress_file(
    input_path: Path,
    output_path: Optional[Path] = None,
    level: int = 6,
    chunk_size: int = 8192
) -> Path:
    """
    Compress a file using gzip.
    
    Args:
        input_path: Path to input file
        output_path: Path for compressed file (default: input + .gz)
        level: Compression level (1-9)
        chunk_size: Size of chunks to read
    
    Returns:
        Path to compressed file
    """
    if output_path is None:
        output_path = input_path.with_suffix(input_path.suffix + ".gz")
    
    with open(input_path, 'rb') as f_in:
        with gzip.open(output_path, 'wb', compresslevel=level) as f_out:
            while chunk := f_in.read(chunk_size):
                f_out.write(chunk)
    
    logger.debug(f"Compressed: {input_path} -> {output_path}")
    return output_path


def decompress_file(
    input_path: Path,
    output_path: Optional[Path] = None,
    chunk_size: int = 8192
) -> Path:
    """
    Decompress a gzip file.
    
    Args:
        input_path: Path to compressed file
        output_path: Path for decompressed file (default: remove .gz)
        chunk_size: Size of chunks to read
    
    Returns:
        Path to decompressed file
    """
    if output_path is None:
        if input_path.suffix == ".gz":
            output_path = input_path.with_suffix("")
        else:
            output_path = input_path.with_suffix(".decompressed")
    
    with gzip.open(input_path, 'rb') as f_in:
        with open(output_path, 'wb') as f_out:
            while chunk := f_in.read(chunk_size):
                f_out.write(chunk)
    
    logger.debug(f"Decompressed: {input_path} -> {output_path}")
    return output_path


def get_compression_ratio(original_path: Path, compressed_path: Path) -> float:
    """
    Calculate compression ratio.
    
    Args:
        original_path: Path to original file
        compressed_path: Path to compressed file
    
    Returns:
        Compression ratio (smaller is better)
    """
    original_size = original_path.stat().st_size
    compressed_size = compressed_path.stat().st_size
    
    if original_size == 0:
        return 1.0
    
    return compressed_size / original_size