Module refinery.units.formats.qr

from __future__ import annotations

import sys

from refinery.lib.exceptions import RefineryImportError
from refinery.lib.structures import MemoryFile
from refinery.units import Unit

if sys.platform.startswith('win'):
    _ZBAR_FOOTNOTE = None
    _ZBAR_ON_ERROR = None
    _ZBAR__INSTALL = None
else:
    _ZBAR_FOOTNOTE = 'you will also have to install the zbar shared library'
    _ZBAR_ON_ERROR = 'you have to install the zbar shared library'
    _ZBAR__INSTALL = None
    if sys.platform == 'darwin':
        _ZBAR__INSTALL = 'brew install zbar'
    if sys.platform == 'linux':
        import shutil
        for mngr, cmd in {
            'apt'    : 'install libzbar0',
            'dnf'    : 'install zbar',
            'yum'    : 'install zbar',
            'pacman' : '-S zbar',
            'zypper' : 'instasll zbar',
            'apk'    : 'add zbar',
            'emerge' : 'media-libs/zbar',
        }.items():
            try:
                if shutil.which(mngr):
                    _ZBAR__INSTALL = F'{mngr} {cmd}'
                    break
            except BaseException:
                break


if _ZBAR_ON_ERROR:
    _ZBAR_FOOTNOTE = F'{_ZBAR_FOOTNOTE}; {_ZBAR__INSTALL}'
    _ZBAR_ON_ERROR = F'{_ZBAR_ON_ERROR}; {_ZBAR__INSTALL}'


class qr(Unit):
    """
    Extract information from bar codes, especially QR codes. This unit is a thin proxy around the
    pyzbar library, which itself only provides Python bindings for the ZBar library.
    """
    @Unit.Requires('pyzbar', ['formats', 'extended', 'all'], info=_ZBAR_FOOTNOTE)
    def _pyzbar():
        try:
            import pyzbar
            import pyzbar.pyzbar
        except ModuleNotFoundError:
            raise
        except ImportError as ie:
            msg = str(ie).split()
            if 'zbar' in msg and 'shared' in msg:
                if info := _ZBAR_ON_ERROR:
                    raise RefineryImportError(info)
            raise RefineryImportError(F'there was an unexpected error importing pyzbar: {ie!s}')
        return pyzbar

    @Unit.Requires('Pillow', ['formats', 'extended', 'all'])
    def _image():
        from PIL import Image
        return Image

    def process(self, data):
        try:
            img = self._image.open(MemoryFile(data, output=bytes))
        except ImportError:
            raise
        except Exception:
            raise ValueError('the input data is not recognized as an image')
        else:
            bar = self._pyzbar.pyzbar.decode(img)
        for data in bar:
            self.log_debug(data)
            if not (data := getattr(data, 'data', None)):
                continue
            if isinstance(data, str):
                data = data.encode(self.codec)
            if isinstance(data, (bytes, bytearray)):
                yield data
                continue
            self.log_warn(
                F'skipping unknown data generated by zbar: {data!r}', clip=True)