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 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.rel.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

    @filter_hook
    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):
        return super(ModelFormAdminView, self).get_media() + self.form_obj.media + \
            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}