domain/value_objects/audio_format.py

"""Audio format value object."""
from typing import List
from dataclasses import dataclass

from ..exceptions.domain_exceptions import InvalidAudioFormatError

@dataclass(frozen=True)
class AudioFormat:
    """Value object representing an audio format."""
    value: str
    
    # Supported formats with their characteristics
    FORMATS = {
        'mp3': {'extension': '.mp3', 'mime_type': 'audio/mpeg', 'lossy': True},
        'aac': {'extension': '.aac', 'mime_type': 'audio/aac', 'lossy': True},
        'wav': {'extension': '.wav', 'mime_type': 'audio/wav', 'lossy': False},
        'flac': {'extension': '.flac', 'mime_type': 'audio/flac', 'lossy': False},
        'm4a': {'extension': '.m4a', 'mime_type': 'audio/mp4', 'lossy': True},
        'ogg': {'extension': '.ogg', 'mime_type': 'audio/ogg', 'lossy': True}
    }
    
    def __post_init__(self):
        if self.value.lower() not in self.FORMATS:
            raise InvalidAudioFormatError(self.value, list(self.FORMATS.keys()))
        
        # Normalize to lowercase
        object.__setattr__(self, 'value', self.value.lower())
    
    @property
    def extension(self) -> str:
        """Get file extension for this format."""
        return self.FORMATS[self.value]['extension']
    
    @property
    def mime_type(self) -> str:
        """Get MIME type for this format."""
        return self.FORMATS[self.value]['mime_type']
    
    @property
    def is_lossy(self) -> bool:
        """Check if format uses lossy compression."""
        return self.FORMATS[self.value]['lossy']
    
    @classmethod
    def supported_formats(cls) -> List[str]:
        """Get list of supported formats."""
        return list(cls.FORMATS.keys())
    
    def __str__(self) -> str:
        return self.value