from django.core.management.base import LabelCommand, CommandError

from django.utils.encoding import force_unicode

class Command(LabelCommand):

    help = "Outputs the specified model as a form definition to the shell."

    args = "[app.model]"

    label = 'application name and model name'

    requires_model_validation = True

    can_import_settings = True

    def handle_label(self, label, **options):    

        return describe_form(label)

def describe_form(label, fields=None):

    """

    Returns a string describing a form based on the model

    """

    from django.db.models.loading import get_model

    try:

        app_name, model_name = label.split('.')[-2:]

    except (IndexError, ValueError):

        raise CommandError("Need application and model name in the form: appname.model")

    model = get_model(app_name, model_name)

    opts = model._meta

    field_list = []

    for f in opts.fields + opts.many_to_many:

        if not f.editable:

            continue

        if fields and not f.name in fields:

            continue

        formfield = f.formfield()

        if not '__dict__' in dir(formfield):

            continue

        attrs = {}

        valid_fields = ['required', 'initial', 'max_length', 'min_length', 'max_value', 'min_value', 'max_digits', 'decimal_places', 'choices', 'help_text', 'label']

        for k,v in formfield.__dict__.items():

            if k in valid_fields and v != None:

                # ignore defaults, to minimize verbosity

                if k == 'required' and v:

                    continue

                if k == 'help_text' and not v:

                    continue

                if k == 'widget':

                    attrs[k] = v.__class__

                elif k in ['help_text', 'label']:

                    attrs[k] = force_unicode(v).strip()

                else:

                    attrs[k] = v

        params = ', '.join(['%s=%r' % (k, v) for k, v in attrs.items()])

        field_list.append('    %(field_name)s = forms.%(field_type)s(%(params)s)' % { 'field_name': f.name, 

                                                                                  'field_type': formfield.__class__.__name__, 

                                                                                  'params': params })

    return '''

from django import forms

from %(app_name)s.models import %(object_name)s

class %(object_name)sForm(forms.Form):

%(field_list)s

''' % { 'app_name': app_name, 'object_name': opts.object_name,  'field_list': '\n'.join(field_list) }