# Source code for lxml.html.formfill

    from lxml.etree import XPath, ElementBase
    from lxml.html import fromstring, XHTML_NAMESPACE
    from lxml.html import _forms_xpath, _options_xpath, _nons, _transform_result
    from lxml.html import defs
    import copy

    try:
        basestring
    except NameError:
        # Python 3
        basestring = str

    __all__ = ['FormNotFound', 'fill_form', 'fill_form_html',
               'insert_errors', 'insert_errors_html',
               'DefaultErrorCreator']

    class FormNotFound(LookupError):
        """
        Raised when no form can be found
        """

    _form_name_xpath = XPath('descendant-or-self::form[name=$name]|descendant-or-self::x:form[name=$name]', namespaces={'x':XHTML_NAMESPACE})
    _input_xpath = XPath('|'.join(['descendant-or-self::'+_tag for _tag in ('input','select','textarea','x:input','x:select','x:textarea')]),
                                   namespaces={'x':XHTML_NAMESPACE})
    _label_for_xpath = XPath('//label[@for=$for_id]|//x:label[@for=$for_id]',
                                   namespaces={'x':XHTML_NAMESPACE})
    _name_xpath = XPath('descendant-or-self::*[@name=$name]')

    def fill_form(
        el,
        values,
        form_id=None,
        form_index=None,
        ):
        el = _find_form(el, form_id=form_id, form_index=form_index)
        _fill_form(el, values)

    def fill_form_html(html, values, form_id=None, form_index=None):
        result_type = type(html)
        if isinstance(html, basestring):
            doc = fromstring(html)
        else:
            doc = copy.deepcopy(html)
        fill_form(doc, values, form_id=form_id, form_index=form_index)
        return _transform_result(result_type, doc)

    def _fill_form(el, values):
        counts = {}
        if hasattr(values, 'mixed'):
            # For Paste request parameters
            values = values.mixed()
        inputs = _input_xpath(el)
        for input in inputs:
            name = input.get('name')
            if not name:
                continue
            if _takes_multiple(input):
                value = values.get(name, [])
                if not isinstance(value, (list, tuple)):
                    value = [value]
                _fill_multiple(input, value)
            elif name not in values:
                continue
            else:
                index = counts.get(name, 0)
                counts[name] = index + 1
                value = values[name]
                if isinstance(value, (list, tuple)):
                    try:
                        value = value[index]
                    except IndexError:
                        continue
                elif index > 0:
                    continue
                _fill_single(input, value)

    def _takes_multiple(input):
        if _nons(input.tag) == 'select' and input.get('multiple'):
            # FIXME: multiple="0"?
            return True
        type = input.get('type', '').lower()
        if type in ('radio', 'checkbox'):
            return True
        return False

    def _fill_multiple(input, value):
        type = input.get('type', '').lower()
        if type == 'checkbox':
            v = input.get('value')
            if v is None:
                if not value:
                    result = False
                else:
                    result = value[0]
                    if isinstance(value, basestring):
                        # The only valid "on" value for an unnamed checkbox is 'on'
                        result = result == 'on'
                _check(input, result)
            else:
                _check(input, v in value)
        elif type == 'radio':
            v = input.get('value')
            _check(input, v in value)
        else:
            assert _nons(input.tag) == 'select'
            for option in _options_xpath(input):
                v = option.get('value')
                if v is None:
                    # This seems to be the default, at least on IE
                    # FIXME: but I'm not sure
                    v = option.text_content()
                _select(option, v in value)

    def _check(el, check):
        if check:
            el.set('checked', '')
        else:
            if 'checked' in el.attrib:
                del el.attrib['checked']

    def _select(el, select):
        if select:
            el.set('selected', '')
        else:
            if 'selected' in el.attrib:
                del el.attrib['selected']

    def _fill_single(input, value):
        if _nons(input.tag) == 'textarea':
            input.text = value
        else:
            input.set('value', value)

    def _find_form(el, form_id=None, form_index=None):
        if form_id is None and form_index is None:
            forms = _forms_xpath(el)
            for form in forms:
                return form
            raise FormNotFound(
                "No forms in page")
        if form_id is not None:
            form = el.get_element_by_id(form_id)
            if form is not None:
                return form
            forms = _form_name_xpath(el, name=form_id)
            if forms:
                return forms[0]
            else:
                raise FormNotFound(
                    "No form with the name or id of %r (forms: %s)"
                    % (id, ', '.join(_find_form_ids(el))))
        if form_index is not None:
            forms = _forms_xpath(el)
            try:
                return forms[form_index]
            except IndexError:
                raise FormNotFound(
                    "There is no form with the index %r (%i forms found)"
                    % (form_index, len(forms)))

    def _find_form_ids(el):
        forms = _forms_xpath(el)
        if not forms:
            yield '(no forms)'
            return
        for index, form in enumerate(forms):
            if form.get('id'):
                if form.get('name'):
                    yield '%s or %s' % (form.get('id'),
                                         form.get('name'))
                else:
                    yield form.get('id')
            elif form.get('name'):
                yield form.get('name')
            else:
                yield '(unnamed form %s)' % index

    ############################################################
    ## Error filling
    ############################################################

    class DefaultErrorCreator:
        insert_before = True
        block_inside = True
        error_container_tag = 'div'
        error_message_class = 'error-message'
        error_block_class = 'error-block'
        default_message = "Invalid"

        def __init__(self, **kw):
            for name, value in kw.items():
                if not hasattr(self, name):
                    raise TypeError(
                        "Unexpected keyword argument: %s" % name)
                setattr(self, name, value)

        def __call__(self, el, is_block, message):
            error_el = el.makeelement(self.error_container_tag)
            if self.error_message_class:
                error_el.set('class', self.error_message_class)
            if is_block and self.error_block_class:
                error_el.set('class', error_el.get('class', '')+' '+self.error_block_class)
            if message is None or message == '':
                message = self.default_message
            if isinstance(message, ElementBase):
                error_el.append(message)
            else:
                assert isinstance(message, basestring), (
                    "Bad message; should be a string or element: %r" % message)
                error_el.text = message or self.default_message
            if is_block and self.block_inside:
                if self.insert_before:
                    error_el.tail = el.text
                    el.text = None
                    el.insert(0, error_el)
                else:
                    el.append(error_el)
            else:
                parent = el.getparent()
                pos = parent.index(el)
                if self.insert_before:
                    parent.insert(pos, error_el)
                else:
                    error_el.tail = el.tail
                    el.tail = None
                    parent.insert(pos+1, error_el)

    default_error_creator = DefaultErrorCreator()

    def insert_errors(
        el,
        errors,
        form_id=None,
        form_index=None,
        error_class="error",
        error_creator=default_error_creator,
        ):
        el = _find_form(el, form_id=form_id, form_index=form_index)
        for name, error in errors.items():
            if error is None:
                continue
            for error_el, message in _find_elements_for_name(el, name, error):
                assert isinstance(message, (basestring, type(None), ElementBase)), (
                    "Bad message: %r" % message)
                _insert_error(error_el, message, error_class, error_creator)

    def insert_errors_html(html, values, **kw):
        result_type = type(html)
        if isinstance(html, basestring):
            doc = fromstring(html)
        else:
            doc = copy.deepcopy(html)
        insert_errors(doc, values, **kw)
        return _transform_result(result_type, doc)

    def _insert_error(el, error, error_class, error_creator):
        if _nons(el.tag) in defs.empty_tags or _nons(el.tag) == 'textarea':
            is_block = False
        else:
            is_block = True
        if _nons(el.tag) != 'form' and error_class:
            _add_class(el, error_class)
        if el.get('id'):
            labels = _label_for_xpath(el, for_id=el.get('id'))
            if labels:
                for label in labels:
                    _add_class(label, error_class)
        error_creator(el, is_block, error)

    def _add_class(el, class_name):
        if el.get('class'):
            el.set('class', el.get('class')+' '+class_name)
        else:
            el.set('class', class_name)

    def _find_elements_for_name(form, name, error):
        if name is None:
            # An error for the entire form
            yield form, error
            return
        if name.startswith('#'):
            # By id
            el = form.get_element_by_id(name[1:])
            if el is not None:
                yield el, error
            return
        els = _name_xpath(form, name=name)
        if not els:
            # FIXME: should this raise an exception?
            return
        if not isinstance(error, (list, tuple)):
            yield els[0], error
            return
        # FIXME: if error is longer than els, should it raise an error?
        for el, err in zip(els, error):
            if err is None:
                continue
            yield el, err