"""

HTML Widget classes

"""

try:

    set

except NameError:

    from sets import Set as set   # Python 2.3 fallback

import copy

from itertools import chain

from django.utils.datastructures import MultiValueDict

from django.utils.html import escape, conditional_escape

from django.utils.translation import ugettext

from django.utils.encoding import StrAndUnicode, force_unicode

from django.utils.safestring import mark_safe

from util import flatatt

__all__ = (

    'Widget', 'TextInput', 'PasswordInput',

    'HiddenInput', 'MultipleHiddenInput',

    'FileInput', 'DateTimeInput', 'Textarea', 'CheckboxInput',

    'Select', 'NullBooleanSelect', 'SelectMultiple', 'RadioSelect',

    'CheckboxSelectMultiple', 'MultiWidget', 'SplitDateTimeWidget',

)

class Widget(object):

    is_hidden = False          # Determines whether this corresponds to an <input type="hidden">.

    needs_multipart_form = False # Determines does this widget need multipart-encrypted form

    def __init__(self, attrs=None):

        if attrs is not None:

            self.attrs = attrs.copy()

        else:

            self.attrs = {}

    def __deepcopy__(self, memo):

        obj = copy.copy(self)

        obj.attrs = self.attrs.copy()

        memo[id(self)] = obj

        return obj

    def render(self, name, value, attrs=None):

        """

        Returns this Widget rendered as HTML, as a Unicode string.

        The 'value' given is not guaranteed to be valid input, so subclass

        implementations should program defensively.

        """

        raise NotImplementedError

    def build_attrs(self, extra_attrs=None, **kwargs):

        "Helper function for building an attribute dictionary."

        attrs = dict(self.attrs, **kwargs)

        if extra_attrs:

            attrs.update(extra_attrs)

        return attrs

    def value_from_datadict(self, data, files, name):

        """

        Given a dictionary of data and this widget's name, returns the value

        of this widget. Returns None if it's not provided.

        """

        return data.get(name, None)

    def id_for_label(self, id_):

        """

        Returns the HTML ID attribute of this Widget for use by a <label>,

        given the ID of the field. Returns None if no ID is available.

        This hook is necessary because some widgets have multiple HTML

        elements and, thus, multiple IDs. In that case, this method should

        return an ID value that corresponds to the first ID in the widget's

        tags.

        """

        return id_

    id_for_label = classmethod(id_for_label)

class Input(Widget):

    """

    Base class for all <input> widgets (except type='checkbox' and

    type='radio', which are special).

    """

    input_type = None # Subclasses must define this.

    def render(self, name, value, attrs=None):

        if value is None: value = ''

        final_attrs = self.build_attrs(attrs, type=self.input_type, name=name)

        if value != '':

            # Only add the 'value' attribute if a value is non-empty.

            final_attrs['value'] = force_unicode(value)

        return mark_safe(u'<input%s />' % flatatt(final_attrs))

class TextInput(Input):

    input_type = 'text'

class PasswordInput(Input):

    input_type = 'password'

    def __init__(self, attrs=None, render_value=True):

        super(PasswordInput, self).__init__(attrs)

        self.render_value = render_value

    def render(self, name, value, attrs=None):

        if not self.render_value: value=None

        return super(PasswordInput, self).render(name, value, attrs)

class HiddenInput(Input):

    input_type = 'hidden'

    is_hidden = True

class MultipleHiddenInput(HiddenInput):

    """

    A widget that handles <input type="hidden"> for fields that have a list

    of values.

    """

    def __init__(self, attrs=None, choices=()):

        super(MultipleHiddenInput, self).__init__(attrs)

        # choices can be any iterable

        self.choices = choices

    def render(self, name, value, attrs=None, choices=()):

        if value is None: value = []

        final_attrs = self.build_attrs(attrs, type=self.input_type, name=name)

        return mark_safe(u'\n'.join([(u'<input%s />' %

            flatatt(dict(value=force_unicode(v), **final_attrs)))

            for v in value]))

    def value_from_datadict(self, data, files, name):

        if isinstance(data, MultiValueDict):

            return data.getlist(name)

        return data.get(name, None)

class FileInput(Input):

    input_type = 'file'

    needs_multipart_form = True

    def render(self, name, value, attrs=None):

        return super(FileInput, self).render(name, None, attrs=attrs)

    def value_from_datadict(self, data, files, name):

        "File widgets take data from FILES, not POST"

        return files.get(name, None)

class Textarea(Widget):

    def __init__(self, attrs=None):

        # The 'rows' and 'cols' attributes are required for HTML correctness.

        self.attrs = {'cols': '40', 'rows': '10'}

        if attrs:

            self.attrs.update(attrs)

    def render(self, name, value, attrs=None):

        if value is None: value = ''

        value = force_unicode(value)

        final_attrs = self.build_attrs(attrs, name=name)

        return mark_safe(u'<textarea%s>%s</textarea>' % (flatatt(final_attrs),

                conditional_escape(force_unicode(value))))

class DateTimeInput(Input):

    input_type = 'text'

    format = '%Y-%m-%d %H:%M:%S'     # '2006-10-25 14:30:59'

    def __init__(self, attrs=None, format=None):

        super(DateTimeInput, self).__init__(attrs)

        if format:

            self.format = format

    def render(self, name, value, attrs=None):

        if value is None:

            value = ''

        elif hasattr(value, 'strftime'):

            value = value.strftime(self.format)

        return super(DateTimeInput, self).render(name, value, attrs)

class CheckboxInput(Widget):

    def __init__(self, attrs=None, check_test=bool):

        super(CheckboxInput, self).__init__(attrs)

        # check_test is a callable that takes a value and returns True

        # if the checkbox should be checked for that value.

        self.check_test = check_test

    def render(self, name, value, attrs=None):

        final_attrs = self.build_attrs(attrs, type='checkbox', name=name)

        try:

            result = self.check_test(value)

        except: # Silently catch exceptions

            result = False

        if result:

            final_attrs['checked'] = 'checked'

        if value not in ('', True, False, None):

            # Only add the 'value' attribute if a value is non-empty.

            final_attrs['value'] = force_unicode(value)

        return mark_safe(u'<input%s />' % flatatt(final_attrs))

    def value_from_datadict(self, data, files, name):

        if name not in data:

            # A missing value means False because HTML form submission does not

            # send results for unselected checkboxes.

            return False

        return super(CheckboxInput, self).value_from_datadict(data, files, name)

class Select(Widget):

    def __init__(self, attrs=None, choices=()):

        super(Select, self).__init__(attrs)

        # choices can be any iterable, but we may need to render this widget

        # multiple times. Thus, collapse it into a list so it can be consumed

        # more than once.

        self.choices = list(choices)

    def render(self, name, value, attrs=None, choices=()):

        if value is None: value = ''

        final_attrs = self.build_attrs(attrs, name=name)

        output = [u'<select%s>' % flatatt(final_attrs)]

        # Normalize to string.

        str_value = force_unicode(value)

        for option_value, option_label in chain(self.choices, choices):

            option_value = force_unicode(option_value)

            selected_html = (option_value == str_value) and u' selected="selected"' or ''

            output.append(u'<option value="%s"%s>%s</option>' % (

                    escape(option_value), selected_html,

                    conditional_escape(force_unicode(option_label))))

        output.append(u'</select>')

        return mark_safe(u'\n'.join(output))

class NullBooleanSelect(Select):

    """

    A Select Widget intended to be used with NullBooleanField.

    """

    def __init__(self, attrs=None):

        choices = ((u'1', ugettext('Unknown')), (u'2', ugettext('Yes')), (u'3', ugettext('No')))

        super(NullBooleanSelect, self).__init__(attrs, choices)

    def render(self, name, value, attrs=None, choices=()):

        try:

            value = {True: u'2', False: u'3', u'2': u'2', u'3': u'3'}[value]

        except KeyError:

            value = u'1'

        return super(NullBooleanSelect, self).render(name, value, attrs, choices)

    def value_from_datadict(self, data, files, name):

        value = data.get(name, None)

        return {u'2': True, u'3': False, True: True, False: False}.get(value, None)

class SelectMultiple(Widget):

    def __init__(self, attrs=None, choices=()):

        super(SelectMultiple, self).__init__(attrs)

        # choices can be any iterable

        self.choices = choices

    def render(self, name, value, attrs=None, choices=()):

        if value is None: value = []

        final_attrs = self.build_attrs(attrs, name=name)

        output = [u'<select multiple="multiple"%s>' % flatatt(final_attrs)]

        str_values = set([force_unicode(v) for v in value]) # Normalize to strings.

        for option_value, option_label in chain(self.choices, choices):

            option_value = force_unicode(option_value)

            selected_html = (option_value in str_values) and ' selected="selected"' or ''

            output.append(u'<option value="%s"%s>%s</option>' % (

                    escape(option_value), selected_html,

                    conditional_escape(force_unicode(option_label))))

        output.append(u'</select>')

        return mark_safe(u'\n'.join(output))

    def value_from_datadict(self, data, files, name):

        if isinstance(data, MultiValueDict):

            return data.getlist(name)

        return data.get(name, None)

class RadioInput(StrAndUnicode):

    """

    An object used by RadioFieldRenderer that represents a single

    <input type='radio'>.

    """

    def __init__(self, name, value, attrs, choice, index):

        self.name, self.value = name, value

        self.attrs = attrs

        self.choice_value = force_unicode(choice[0])

        self.choice_label = force_unicode(choice[1])

        self.index = index

    def __unicode__(self):

        return mark_safe(u'<label>%s %s</label>' % (self.tag(),

                conditional_escape(force_unicode(self.choice_label))))

    def is_checked(self):

        return self.value == self.choice_value

    def tag(self):

        if 'id' in self.attrs:

            self.attrs['id'] = '%s_%s' % (self.attrs['id'], self.index)

        final_attrs = dict(self.attrs, type='radio', name=self.name, value=self.choice_value)

        if self.is_checked():

            final_attrs['checked'] = 'checked'

        return mark_safe(u'<input%s />' % flatatt(final_attrs))

class RadioFieldRenderer(StrAndUnicode):

    """

    An object used by RadioSelect to enable customization of radio widgets.

    """

    def __init__(self, name, value, attrs, choices):

        self.name, self.value, self.attrs = name, value, attrs

        self.choices = choices

    def __iter__(self):

        for i, choice in enumerate(self.choices):

            yield RadioInput(self.name, self.value, self.attrs.copy(), choice, i)

    def __getitem__(self, idx):

        choice = self.choices[idx] # Let the IndexError propogate

        return RadioInput(self.name, self.value, self.attrs.copy(), choice, idx)

    def __unicode__(self):

        return self.render()

    def render(self):

        """Outputs a <ul> for this set of radio fields."""

        return mark_safe(u'<ul>\n%s\n</ul>' % u'\n'.join([u'<li>%s</li>'

                % force_unicode(w) for w in self]))

class RadioSelect(Select):

    renderer = RadioFieldRenderer

    def __init__(self, *args, **kwargs):

        # Override the default renderer if we were passed one.

        renderer = kwargs.pop('renderer', None)

        if renderer:

            self.renderer = renderer

        super(RadioSelect, self).__init__(*args, **kwargs)

    def get_renderer(self, name, value, attrs=None, choices=()):

        """Returns an instance of the renderer."""

        if value is None: value = ''

        str_value = force_unicode(value) # Normalize to string.

        final_attrs = self.build_attrs(attrs)

        choices = list(chain(self.choices, choices))

        return self.renderer(name, str_value, final_attrs, choices)

    def render(self, name, value, attrs=None, choices=()):

        return self.get_renderer(name, value, attrs, choices).render()

    def id_for_label(self, id_):

        # RadioSelect is represented by multiple <input type="radio"> fields,

        # each of which has a distinct ID. The IDs are made distinct by a "_X"

        # suffix, where X is the zero-based index of the radio field. Thus,

        # the label for a RadioSelect should reference the first one ('_0').

        if id_:

            id_ += '_0'

        return id_

    id_for_label = classmethod(id_for_label)

class CheckboxSelectMultiple(SelectMultiple):

    def render(self, name, value, attrs=None, choices=()):

        if value is None: value = []

        has_id = attrs and 'id' in attrs

        final_attrs = self.build_attrs(attrs, name=name)

        output = [u'<ul>']

        # Normalize to strings

        str_values = set([force_unicode(v) for v in value])

        for i, (option_value, option_label) in enumerate(chain(self.choices, choices)):

            # If an ID attribute was given, add a numeric index as a suffix,

            # so that the checkboxes don't all have the same ID attribute.

            if has_id:

                final_attrs = dict(final_attrs, id='%s_%s' % (attrs['id'], i))

            cb = CheckboxInput(final_attrs, check_test=lambda value: value in str_values)

            option_value = force_unicode(option_value)

            rendered_cb = cb.render(name, option_value)

            output.append(u'<li><label>%s %s</label></li>' % (rendered_cb,

                    conditional_escape(force_unicode(option_label))))

        output.append(u'</ul>')

        return mark_safe(u'\n'.join(output))

    def id_for_label(self, id_):

        # See the comment for RadioSelect.id_for_label()

        if id_:

            id_ += '_0'

        return id_

    id_for_label = classmethod(id_for_label)

class MultiWidget(Widget):

    """

    A widget that is composed of multiple widgets.

    Its render() method is different than other widgets', because it has to

    figure out how to split a single value for display in multiple widgets.

    The ``value`` argument can be one of two things:

        * A list.

        * A normal value (e.g., a string) that has been "compressed" from

          a list of values.

    In the second case -- i.e., if the value is NOT a list -- render() will

    first "decompress" the value into a list before rendering it. It does so by

    calling the decompress() method, which MultiWidget subclasses must

    implement. This method takes a single "compressed" value and returns a

    list.

    When render() does its HTML rendering, each value in the list is rendered

    with the corresponding widget -- the first value is rendered in the first

    widget, the second value is rendered in the second widget, etc.

    Subclasses may implement format_output(), which takes the list of rendered

    widgets and returns a string of HTML that formats them any way you'd like.

    You'll probably want to use this class with MultiValueField.

    """

    def __init__(self, widgets, attrs=None):

        self.widgets = [isinstance(w, type) and w() or w for w in widgets]

        super(MultiWidget, self).__init__(attrs)

    def render(self, name, value, attrs=None):

        # value is a list of values, each corresponding to a widget

        # in self.widgets.

        if not isinstance(value, list):

            value = self.decompress(value)

        output = []

        final_attrs = self.build_attrs(attrs)

        id_ = final_attrs.get('id', None)

        for i, widget in enumerate(self.widgets):

            try:

                widget_value = value[i]

            except IndexError:

                widget_value = None

            if id_:

                final_attrs = dict(final_attrs, id='%s_%s' % (id_, i))

            output.append(widget.render(name + '_%s' % i, widget_value, final_attrs))

        return mark_safe(self.format_output(output))

    def id_for_label(self, id_):

        # See the comment for RadioSelect.id_for_label()

        if id_:

            id_ += '_0'

        return id_

    id_for_label = classmethod(id_for_label)

    def value_from_datadict(self, data, files, name):

        return [widget.value_from_datadict(data, files, name + '_%s' % i) for i, widget in enumerate(self.widgets)]

    def format_output(self, rendered_widgets):

        """

        Given a list of rendered widgets (as strings), returns a Unicode string

        representing the HTML for the whole lot.

        This hook allows you to format the HTML design of the widgets, if

        needed.

        """

        return u''.join(rendered_widgets)

    def decompress(self, value):

        """

        Returns a list of decompressed values for the given compressed value.

        The given value can be assumed to be valid, but not necessarily

        non-empty.

        """

        raise NotImplementedError('Subclasses must implement this method.')

class SplitDateTimeWidget(MultiWidget):

    """

    A Widget that splits datetime input into two <input type="text"> boxes.

    """

    def __init__(self, attrs=None):

        widgets = (TextInput(attrs=attrs), TextInput(attrs=attrs))

        super(SplitDateTimeWidget, self).__init__(widgets, attrs)

    def decompress(self, value):

        if value:

            return [value.date(), value.time().replace(microsecond=0)]

        return [None, None]