from django import forms

from django.conf import settings

from django.utils.html import escape

from django.utils.safestring import mark_safe

from django.utils.encoding import force_unicode

from django.contrib.admin.util import flatten_fieldsets

from django.contrib.contenttypes.models import ContentType

class AdminForm(object):

    def __init__(self, form, fieldsets, prepopulated_fields):

        self.form, self.fieldsets = form, fieldsets

        self.prepopulated_fields = [{

            'field': form[field_name],

            'dependencies': [form[f] for f in dependencies]

        } for field_name, dependencies in prepopulated_fields.items()]

    def __iter__(self):

        for name, options in self.fieldsets:

            yield Fieldset(self.form, name, **options)

    def first_field(self):

        try:

            fieldset_name, fieldset_options = self.fieldsets[0]

            field_name = fieldset_options['fields'][0]

            if not isinstance(field_name, basestring):

                field_name = field_name[0]

            return self.form[field_name]

        except (KeyError, IndexError):

            pass

        try:

            return iter(self.form).next()

        except StopIteration:

            return None

    def _media(self):

        media = self.form.media

        for fs in self:

            media = media + fs.media

        return media

    media = property(_media)

class Fieldset(object):

    def __init__(self, form, name=None, fields=(), classes=(), description=None):

        self.form = form

        self.name, self.fields = name, fields

        self.classes = u' '.join(classes)

        self.description = description

    def _media(self):

        if 'collapse' in self.classes:

            return forms.Media(js=['%sjs/admin/CollapsedFieldsets.js' % settings.ADMIN_MEDIA_PREFIX])

        return forms.Media()

    media = property(_media)

    def __iter__(self):

        for field in self.fields:

            yield Fieldline(self.form, field)

class Fieldline(object):

    def __init__(self, form, field):

        self.form = form # A django.forms.Form instance

        if isinstance(field, basestring):

            self.fields = [field]

        else:

            self.fields = field

    def __iter__(self):

        for i, field in enumerate(self.fields):

            yield AdminField(self.form, field, is_first=(i == 0))

    def errors(self):

        return mark_safe(u'\n'.join([self.form[f].errors.as_ul() for f in self.fields]).strip('\n'))

class AdminField(object):

    def __init__(self, form, field, is_first):

        self.field = form[field] # A django.forms.BoundField instance

        self.is_first = is_first # Whether this field is first on the line

        self.is_checkbox = isinstance(self.field.field.widget, forms.CheckboxInput)

    def label_tag(self):

        classes = []

        if self.is_checkbox:

            classes.append(u'vCheckboxLabel')

            contents = force_unicode(escape(self.field.label))

        else:

            contents = force_unicode(escape(self.field.label)) + u':'

        if self.field.field.required:

            classes.append(u'required')

        if not self.is_first:

            classes.append(u'inline')

        attrs = classes and {'class': u' '.join(classes)} or {}

        return self.field.label_tag(contents=contents, attrs=attrs)

class InlineAdminFormSet(object):

    """

    A wrapper around an inline formset for use in the admin system.

    """

    def __init__(self, inline, formset, fieldsets):

        self.opts = inline

        self.formset = formset

        self.fieldsets = fieldsets

    def __iter__(self):

        for form, original in zip(self.formset.initial_forms, self.formset.get_queryset()):

            yield InlineAdminForm(self.formset, form, self.fieldsets, self.opts.prepopulated_fields, original)

        for form in self.formset.extra_forms:

            yield InlineAdminForm(self.formset, form, self.fieldsets, self.opts.prepopulated_fields, None)

    def fields(self):

        for field_name in flatten_fieldsets(self.fieldsets):

            yield self.formset.form.base_fields[field_name]

    def _media(self):

        media = self.opts.media + self.formset.media

        for fs in self:

            media = media + fs.media

        return media

    media = property(_media)

class InlineAdminForm(AdminForm):

    """

    A wrapper around an inline form for use in the admin system.

    """

    def __init__(self, formset, form, fieldsets, prepopulated_fields, original):

        self.formset = formset

        self.original = original

        if original is not None:

            self.original.content_type_id = ContentType.objects.get_for_model(original).pk

        self.show_url = original and hasattr(original, 'get_absolute_url')

        super(InlineAdminForm, self).__init__(form, fieldsets, prepopulated_fields)

    def pk_field(self):

        return AdminField(self.form, self.formset._pk_field.name, False)

    def deletion_field(self):

        from django.forms.formsets import DELETION_FIELD_NAME

        return AdminField(self.form, DELETION_FIELD_NAME, False)

    def ordering_field(self):

        from django.forms.formsets import ORDERING_FIELD_NAME

        return AdminField(self.form, ORDERING_FIELD_NAME, False)

class AdminErrorList(forms.util.ErrorList):

    """

    Stores all errors for the form/formsets in an add/change stage view.

    """

    def __init__(self, form, inline_formsets):

        if form.is_bound:

            self.extend(form.errors.values())

            for inline_formset in inline_formsets:

                self.extend(inline_formset.non_form_errors())

                for errors_in_inline_form in inline_formset.errors:

                    self.extend(errors_in_inline_form.values())