from __future__ import absolute_import
import copy

from crispy_forms.utils import TEMPLATE_PACK
from django import forms
from django.contrib.contenttypes.models import ContentType
from django.core.exceptions import PermissionDenied, FieldError
from django.db import models, transaction
from django.forms.models import modelform_factory, modelform_defines_fields
from django.http import Http404, HttpResponseRedirect
from django.template.response import TemplateResponse
from django.utils import six
from django.utils.encoding import force_text
from django.utils.html import escape
from django.utils.text import capfirst, get_text_list
from django.template import loader
from django.utils.translation import ugettext as _
from django.forms.widgets import Media
from xadmin import widgets
from xadmin.layout import FormHelper, Layout, Fieldset, TabHolder, Container, Column, Col, Field
from xadmin.util import unquote
from xadmin.views.detail import DetailAdminUtil

from .base import ModelAdminView, filter_hook, csrf_protect_m


FORMFIELD_FOR_DBFIELD_DEFAULTS = {
    models.DateTimeField: {
        'form_class': forms.SplitDateTimeField,
        'widget': widgets.AdminSplitDateTime
    },
    models.DateField: {'widget': widgets.AdminDateWidget},
    models.TimeField: {'widget': widgets.AdminTimeWidget},
    models.TextField: {'widget': widgets.AdminTextareaWidget},
    models.URLField: {'widget': widgets.AdminURLFieldWidget},
    models.IntegerField: {'widget': widgets.AdminIntegerFieldWidget},
    models.BigIntegerField: {'widget': widgets.AdminIntegerFieldWidget},
    models.CharField: {'widget': widgets.AdminTextInputWidget},
    models.IPAddressField: {'widget': widgets.AdminTextInputWidget},
    models.ImageField: {'widget': widgets.AdminFileWidget},
    models.FileField: {'widget': widgets.AdminFileWidget},
    models.ForeignKey: {'widget': widgets.AdminSelectWidget},
    models.OneToOneField: {'widget': widgets.AdminSelectWidget},
    models.ManyToManyField: {'widget': widgets.AdminSelectMultiple},
}


class ReadOnlyField(Field):
    template = "xadmin/layout/field_value.html"

    def __init__(self, *args, **kwargs):
        self.detail = kwargs.pop('detail')
        super(ReadOnlyField, self).__init__(*args, **kwargs)

    def render(self, form, form_style, context, template_pack=TEMPLATE_PACK, **kwargs):
        html = ''
        for field in self.fields:
            result = self.detail.get_field_result(field)
            field = {'auto_id': field}
            html += loader.render_to_string(
                self.template, {'field': field, 'result': result})
        return html


class ModelFormAdminView(ModelAdminView):
    form = forms.ModelForm
    formfield_overrides = {}
    readonly_fields = ()
    style_fields = {}
    exclude = None
    relfield_style = None

    save_as = False
    save_on_top = False

    add_form_template = None
    change_form_template = None

    form_layout = None

    def __init__(self, request, *args, **kwargs):
        overrides = FORMFIELD_FOR_DBFIELD_DEFAULTS.copy()
        overrides.update(self.formfield_overrides)
        self.formfield_overrides = overrides
        super(ModelFormAdminView, self).__init__(request, *args, **kwargs)

    @filter_hook
    def formfield_for_dbfield(self, db_field, **kwargs):
        # If it uses an intermediary model that isn't auto created, don't show
        # a field in admin.
        if isinstance(db_field, models.ManyToManyField) and not db_field.remote_field.through._meta.auto_created:
            return None

        attrs = self.get_field_attrs(db_field, **kwargs)
        return db_field.formfield(**dict(attrs, **kwargs))

    @filter_hook
    def get_field_style(self, db_field, style, **kwargs):
        if style in ('radio', 'radio-inline') and (db_field.choices or isinstance(db_field, models.ForeignKey)):
            attrs = {'widget': widgets.AdminRadioSelect(
                attrs={'inline': 'inline' if style == 'radio-inline' else ''})}
            if db_field.choices:
                attrs['choices'] = db_field.get_choices(
                    include_blank=db_field.blank,
                    blank_choice=[('', _('Null'))]
                )
            return attrs

        if style in ('checkbox', 'checkbox-inline') and isinstance(db_field, models.ManyToManyField):
            return {'widget': widgets.AdminCheckboxSelect(attrs={'inline': style == 'checkbox-inline'}),
                    'help_text': None}

    @filter_hook
    def get_field_attrs(self, db_field, **kwargs):

        if db_field.name in self.style_fields:
            attrs = self.get_field_style(
                db_field, self.style_fields[db_field.name], **kwargs)
            if attrs:
                return attrs

        if hasattr(db_field, "rel") and db_field.rel:
            related_modeladmin = self.admin_site._registry.get(db_field.rel.to)
            if related_modeladmin and hasattr(related_modeladmin, 'relfield_style'):
                attrs = self.get_field_style(
                    db_field, related_modeladmin.relfield_style, **kwargs)
                if attrs:
                    return attrs

        if db_field.choices:
            return {'widget': widgets.AdminSelectWidget}

        for klass in db_field.__class__.mro():
            if klass in self.formfield_overrides:
                return self.formfield_overrides[klass].copy()

        return {}

    @filter_hook
    def prepare_form(self):
        self.model_form = self.get_model_form()

    @filter_hook
    def instance_forms(self):
        self.form_obj = self.model_form(**self.get_form_datas())

    def setup_forms(self):
        helper = self.get_form_helper()
        if helper:
            self.form_obj.helper = helper

    @filter_hook
    def valid_forms(self):
        return self.form_obj.is_valid()

    @filter_hook
    def get_model_form(self, **kwargs):
        """
        Returns a Form class for use in the admin add view. This is used by
        add_view and change_view.
        """
        if self.exclude is None:
            exclude = []
        else:
            exclude = list(self.exclude)
        exclude.extend(self.get_readonly_fields())
        if self.exclude is None and hasattr(self.form, '_meta') and self.form._meta.exclude:
            # Take the custom ModelForm's Meta.exclude into account only if the
            # ModelAdmin doesn't define its own.
            exclude.extend(self.form._meta.exclude)
        # if exclude is an empty list we pass None to be consistant with the
        # default on modelform_factory
        exclude = exclude or None
        defaults = {
            "form": self.form,
            "fields": self.fields and list(self.fields) or None,
            "exclude": exclude,
            "formfield_callback": self.formfield_for_dbfield,
        }
        defaults.update(kwargs)

        if defaults['fields'] is None and not modelform_defines_fields(defaults['form']):
            defaults['fields'] = forms.ALL_FIELDS

        return modelform_factory(self.model, **defaults)

        try:
            return modelform_factory(self.model, **defaults)
        except FieldError as e:
            raise FieldError('%s. Check fields/fieldsets/exclude attributes of class %s.'
                             % (e, self.__class__.__name__))

    @filter_hook
    def get_form_layout(self):
        layout = copy.deepcopy(self.form_layout)
        arr = self.form_obj.fields.keys()
        if six.PY3:
            arr = [k for k in arr]
        fields = arr + list(self.get_readonly_fields())

        if layout is None:
            layout = Layout(Container(Col('full',
                                          Fieldset("", *fields, css_class="unsort no_title"), horizontal=True, span=12)
                                      ))
        elif type(layout) in (list, tuple) and len(layout) > 0:
            if isinstance(layout[0], Column):
                fs = layout
            elif isinstance(layout[0], (Fieldset, TabHolder)):
                fs = (Col('full', *layout, horizontal=True, span=12),)
            else:
                fs = (Col('full', Fieldset("", *layout, css_class="unsort no_title"), horizontal=True, span=12),)

            layout = Layout(Container(*fs))

            rendered_fields = [i[1] for i in layout.get_field_names()]
            container = layout[0].fields
            other_fieldset = Fieldset(_(u'Other Fields'), *[f for f in fields if f not in rendered_fields])

            if len(other_fieldset.fields):
                if len(container) and isinstance(container[0], Column):
                    container[0].fields.append(other_fieldset)
                else:
                    container.append(other_fieldset)

        return layout

    def get_form_helper(self):
        helper = FormHelper()
        helper.form_tag = False
        helper.include_media = False
        helper.add_layout(self.get_form_layout())

        # deal with readonly fields
        readonly_fields = self.get_readonly_fields()
        if readonly_fields:
            detail = self.get_model_view(
                DetailAdminUtil, self.model, self.form_obj.instance)
            for field in readonly_fields:
                helper[field].wrap(ReadOnlyField, detail=detail)

        return helper

    @filter_hook
    def get_readonly_fields(self):
        """
        Hook for specifying custom readonly fields.
        """
        return self.readonly_fields

    @filter_hook
    def save_forms(self):
        self.new_obj = self.form_obj.save(commit=False)

    @filter_hook
    def change_message(self):
        change_message = []
        if self.org_obj is None:
            change_message.append(_('Added.'))
        elif self.form_obj.changed_data:
            change_message.append(_('Changed %s.') % get_text_list(self.form_obj.changed_data, _('and')))

        change_message = ' '.join(change_message)
        return change_message or _('No fields changed.')

    @filter_hook
    def save_models(self):
        self.new_obj.save()
        flag = self.org_obj is None and 'create' or 'change'
        self.log(flag, self.change_message(), self.new_obj)

    @filter_hook
    def save_related(self):
        self.form_obj.save_m2m()

    @csrf_protect_m
    @filter_hook
    def get(self, request, *args, **kwargs):
        self.instance_forms()
        self.setup_forms()

        return self.get_response()

    @csrf_protect_m
    @transaction.atomic
    @filter_hook
    def post(self, request, *args, **kwargs):
        self.instance_forms()
        self.setup_forms()

        if self.valid_forms():
            self.save_forms()
            self.save_models()
            self.save_related()
            response = self.post_response()
            cls_str = str if six.PY3 else basestring
            if isinstance(response, cls_str):
                return HttpResponseRedirect(response)
            else:
                return response

        return self.get_response()

    @filter_hook
    def get_context(self):
        add = self.org_obj is None
        change = self.org_obj is not None

        new_context = {
            'form': self.form_obj,
            'original': self.org_obj,
            'show_delete': self.org_obj is not None,
            'add': add,
            'change': change,
            'errors': self.get_error_list(),

            'has_add_permission': self.has_add_permission(),
            'has_view_permission': self.has_view_permission(),
            'has_change_permission': self.has_change_permission(self.org_obj),
            'has_delete_permission': self.has_delete_permission(self.org_obj),

            'has_file_field': True,  # FIXME - this should check if form or formsets have a FileField,
            'has_absolute_url': hasattr(self.model, 'get_absolute_url'),
            'form_url': '',
            'content_type_id': ContentType.objects.get_for_model(self.model).id,
            'save_as': self.save_as,
            'save_on_top': self.save_on_top,
        }

        # for submit line
        new_context.update({
            'onclick_attrib': '',
            'show_delete_link': (new_context['has_delete_permission']
                                 and (change or new_context['show_delete'])),
            'show_save_as_new': change and self.save_as,
            'show_save_and_add_another': new_context['has_add_permission'] and
                                (not self.save_as or add),
            'show_save_and_continue': new_context['has_change_permission'],
            'show_save': True
        })

        if self.org_obj and new_context['show_delete_link']:
            new_context['delete_url'] = self.model_admin_url(
                'delete', self.org_obj.pk)

        context = super(ModelFormAdminView, self).get_context()
        context.update(new_context)
        return context

    @filter_hook
    def get_error_list(self):
        errors = forms.utils.ErrorList()
        if self.form_obj.is_bound:
            errors.extend(self.form_obj.errors.values())
        return errors

    @filter_hook
    def get_media(self):
        try:
            m = self.form_obj.media
        except:
            m = Media()
        return super(ModelFormAdminView, self).get_media() + m + \
            self.vendor('xadmin.page.form.js', 'xadmin.form.css')


class CreateAdminView(ModelFormAdminView):

    def init_request(self, *args, **kwargs):
        self.org_obj = None

        if not self.has_add_permission():
            raise PermissionDenied

        # comm method for both get and post
        self.prepare_form()

    @filter_hook
    def get_form_datas(self):
        # Prepare the dict of initial data from the request.
        # We have to special-case M2Ms as a list of comma-separated PKs.
        if self.request_method == 'get':
            initial = dict(self.request.GET.items())
            for k in initial:
                try:
                    f = self.opts.get_field(k)
                except models.FieldDoesNotExist:
                    continue
                if isinstance(f, models.ManyToManyField):
                    initial[k] = initial[k].split(",")
            return {'initial': initial}
        else:
            return {'data': self.request.POST, 'files': self.request.FILES}

    @filter_hook
    def get_context(self):
        new_context = {
            'title': _('Add %s') % force_text(self.opts.verbose_name),
        }
        context = super(CreateAdminView, self).get_context()
        context.update(new_context)
        return context

    @filter_hook
    def get_breadcrumb(self):
        bcs = super(ModelFormAdminView, self).get_breadcrumb()
        item = {'title': _('Add %s') % force_text(self.opts.verbose_name)}
        if self.has_add_permission():
            item['url'] = self.model_admin_url('add')
        bcs.append(item)
        return bcs

    @filter_hook
    def get_response(self):
        context = self.get_context()
        context.update(self.kwargs or {})

        return TemplateResponse(
            self.request, self.add_form_template or self.get_template_list(
                'views/model_form.html'),
            context)

    @filter_hook
    def post_response(self):
        """
        Determines the HttpResponse for the add_view stage.
        """
        request = self.request

        msg = _(
            'The %(name)s "%(obj)s" was added successfully.') % {'name': force_text(self.opts.verbose_name),
                                                                 'obj': "<a class='alert-link' href='%s'>%s</a>" % (self.model_admin_url('change', self.new_obj._get_pk_val()), force_text(self.new_obj))}

        if "_continue" in request.POST:
            self.message_user(
                msg + ' ' + _("You may edit it again below."), 'success')
            return self.model_admin_url('change', self.new_obj._get_pk_val())

        if "_addanother" in request.POST:
            self.message_user(msg + ' ' + (_("You may add another %s below.") % force_text(self.opts.verbose_name)), 'success')
            return request.path
        else:
            self.message_user(msg, 'success')

            # Figure out where to redirect. If the user has change permission,
            # redirect to the change-list page for this object. Otherwise,
            # redirect to the admin index.
            if "_redirect" in request.POST:
                return request.POST["_redirect"]
            elif self.has_view_permission():
                return self.model_admin_url('changelist')
            else:
                return self.get_admin_url('index')


class UpdateAdminView(ModelFormAdminView):

    def init_request(self, object_id, *args, **kwargs):
        self.org_obj = self.get_object(unquote(object_id))

        if not self.has_change_permission(self.org_obj):
            raise PermissionDenied

        if self.org_obj is None:
            raise Http404(_('%(name)s object with primary key %(key)r does not exist.') %
                          {'name': force_text(self.opts.verbose_name), 'key': escape(object_id)})

        # comm method for both get and post
        self.prepare_form()

    @filter_hook
    def get_form_datas(self):
        params = {'instance': self.org_obj}
        if self.request_method == 'post':
            params.update(
                {'data': self.request.POST, 'files': self.request.FILES})
        return params

    @filter_hook
    def get_context(self):
        new_context = {
            'title': _('Change %s') % force_text(self.org_obj),
            'object_id': str(self.org_obj.pk),
        }
        context = super(UpdateAdminView, self).get_context()
        context.update(new_context)
        return context

    @filter_hook
    def get_breadcrumb(self):
        bcs = super(ModelFormAdminView, self).get_breadcrumb()

        item = {'title': force_text(self.org_obj)}
        if self.has_change_permission():
            item['url'] = self.model_admin_url('change', self.org_obj.pk)
        bcs.append(item)

        return bcs

    @filter_hook
    def get_response(self, *args, **kwargs):
        context = self.get_context()
        context.update(kwargs or {})

        return TemplateResponse(
            self.request, self.change_form_template or self.get_template_list(
                'views/model_form.html'),
            context)

    def post(self, request, *args, **kwargs):
        if "_saveasnew" in self.request.POST:
            return self.get_model_view(CreateAdminView, self.model).post(request)
        return super(UpdateAdminView, self).post(request, *args, **kwargs)

    @filter_hook
    def post_response(self):
        """
        Determines the HttpResponse for the change_view stage.
        """
        opts = self.new_obj._meta
        obj = self.new_obj
        request = self.request
        verbose_name = opts.verbose_name

        pk_value = obj._get_pk_val()

        msg = _('The %(name)s "%(obj)s" was changed successfully.') % {'name':
                                                                       force_text(verbose_name), 'obj': force_text(obj)}
        if "_continue" in request.POST:
            self.message_user(
                msg + ' ' + _("You may edit it again below."), 'success')
            return request.path
        elif "_addanother" in request.POST:
            self.message_user(msg + ' ' + (_("You may add another %s below.")
                                           % force_text(verbose_name)), 'success')
            return self.model_admin_url('add')
        else:
            self.message_user(msg, 'success')
            # Figure out where to redirect. If the user has change permission,
            # redirect to the change-list page for this object. Otherwise,
            # redirect to the admin index.
            if "_redirect" in request.POST:
                return request.POST["_redirect"]
            elif self.has_view_permission():
                change_list_url = self.model_admin_url('changelist')
                if 'LIST_QUERY' in self.request.session \
                        and self.request.session['LIST_QUERY'][0] == self.model_info:
                    change_list_url += '?' + self.request.session['LIST_QUERY'][1]
                return change_list_url
            else:
                return self.get_admin_url('index')


class ModelFormAdminUtil(ModelFormAdminView):

    def init_request(self, obj=None):
        self.org_obj = obj
        self.prepare_form()
        self.instance_forms()

    @filter_hook
    def get_form_datas(self):
        return {'instance': self.org_obj}