from .base import (
    CaptionConverter, CaptionNode, Caption, CaptionList, CaptionSet)
from .dfxp import DFXPWriter, DFXPReader
from .microdvd import MicroDVDReader, MicroDVDWriter
from .sami import SAMIReader, SAMIWriter
from .srt import SRTReader, SRTWriter
from .scc import SCCReader, SCCWriter
from .webvtt import WebVTTReader, WebVTTWriter
from .exceptions import (
    CaptionReadError, CaptionReadNoCaptions, CaptionReadSyntaxError)


__all__ = [
    'CaptionConverter', 'DFXPReader', 'DFXPWriter',
    'SAMIReader', 'SAMIWriter', 'SRTReader', 'SRTWriter',
    'SCCReader', 'SCCWriter', 'WebVTTReader', 'WebVTTWriter',
    'CaptionReadError', 'CaptionReadNoCaptions', 'CaptionReadSyntaxError',
    'detect_format', 'CaptionNode', 'Caption', 'CaptionList', 'CaptionSet'
]

SUPPORTED_READERS = (
    DFXPReader, MicroDVDReader, WebVTTReader, SAMIReader, SRTReader, SCCReader)


def detect_format(caps):
    """
    Detect the format of the provided caption string.

    :returns: the reader class for the detected format.
    """
    for reader in SUPPORTED_READERS:
        if reader().detect(caps):
            return reader

    return None
