"""
A custom transform using external command
"""

import os.path
from os import popen3
from Products.PortalTransforms.interfaces import ITransform
from zope.interface import implements
from Products.PortalTransforms.libtransforms.commandtransform import \
    commandtransform
from Products.PortalTransforms.utils import log


class ExternalCommandTransform(commandtransform):
    """ Custom external command

    transform content by launching an external command

    the command should take the content in an input file (designed by '%s' in
    the command line parameters) and return output on stdout.
    Input and output mime types must be set correctly !
    """
    implements(ITransform)

    __name__ = "command_transform"

    def __init__(self, name=None, input_extension=None, **kwargs):
        self.config = {
            'binary_path': '',
            'command_line': '',
            'inputs': ('text/plain',),
            'output': 'text/plain',
            }
        self.config_metadata = {
            'binary_path': (
                'string',
                'Binary path',
                'Path of the executable on the server.'),
            'command_line': (
                'string',
                'Command line',
                '''Additional command line option.
There should be at least the input file (designed by "%(input)s").
The transformation\'s result must be printed on stdout.
'''),
            'inputs': (
                'list',
                'Inputs',
                'Input(s) MIME type. Change with care.'),
            'output': (
                'string',
                'Output',
                'Output MIME type. Change with care.'),
            }
        self.config.update(kwargs)
        commandtransform.__init__(self, name=name,
                                  binary=self.config['binary_path'], **kwargs)

        # use the full binary path
        self.config.update({'binary_path': self.binary})
        self.input_extension = input_extension

    def __getattr__(self, attr):
        if attr == 'inputs':
            return self.config['inputs']
        if attr == 'output':
            return self.config['output']
        raise AttributeError(attr)

    def convert(self, data, cache, **kwargs):
        filename = kwargs.get('filename') or 'unknown'
        if self.input_extension is not None:
            kwargs['filename'] = 'unknown' + self.input_extension
        else:
            kwargs['filename'] = 'unknown' + os.path.splitext(filename)[-1]
        tmpdir, fullname = self.initialize_tmpdir(data, **kwargs)

        data = self.invokeCommand(fullname)
        cache.setData(data)
        path, images = self.subObjects(tmpdir)
        objects = {}
        if images:
            self.fixImages(path, images, objects)
            cache.setSubObjects(objects)
        self.cleanDir(tmpdir)
        return cache

    def invokeCommand(self, input_name):
        command = '%(binary_path)s %(command_line)s' % self.config
        input, output, error = popen3(command % input_name)
        input.close()
        # first read stderr, else we may hang on stout
        # but, still hang my windows, so commented it :-(
        # error_data = error.read()
        error_data = 'error while running "%s"' % (command % input_name)
        error.close()
        data = output.read()
        output.close()
        if error_data and not data:
            data = error_data
        else:
            log('Error while running "%s":\n %s' % (command % input_name,
                                                    error_data))
        return data


def register():
    return ExternalCommandTransform()
