# coding=utf-8

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals

import collections

from django import forms
from django.db import models
from django.conf import settings
from django.contrib.contenttypes.models import ContentType
from django.core.exceptions import ValidationError
from django.db import transaction
from django.utils.encoding import force_text
from datetimewidget import widgets as dtwidgets

from rapid.widgets import RapidSelector, rapid_alternatives_widget, rapid_dependent_widget, \
    getRapidReadonlyRelation
from rapid.wrappers import FieldData, ModelData

import gettext
_ = gettext.gettext


class RapidAlternativesField(forms.Field):
    """
    Form field for AlternativeData.
    """
    def __init__(self, field_name, alternatives, selector_name, form, request, instance=None, *args, **kwargs):
        model = None
        if instance:
            model = getattr(instance, selector_name)
        if form.base_fields[selector_name].initial:
            model = ContentType.objects.get_for_id(form.base_fields[selector_name].initial)
        alt = []
        for a in alternatives:
            md = ModelData(a)
            ft = for_model(request, a)
            prefix = field_name + '_' + str(md.content_type().pk)
            selected = ContentType.objects.get_for_model(a) == model
            inst = getattr(instance, field_name) if selected else None
            if request.method == 'POST':
                fm = ft(request.POST, request.FILES, prefix=prefix, instance=inst)
            else:
                fm = ft(prefix=prefix, instance=inst)
            alt.append((md.content_type().pk, (md, fm, selected)))
        alt = dict(alt)
        kwargs['widget'] = rapid_alternatives_widget(alt, selector_name)
        # noinspection PyArgumentList
        super(RapidAlternativesField, self).__init__(field_name, *args, **kwargs)

    def to_python(self, value):
        if value is None:
            return None
        if value.is_valid():
            obj = value.save(commit=False)
            obj.save_m2m = value.save_m2m
            return obj
        raise ValidationError(_("Invalid value"), code='invalid')


class RapidDependentField(forms.Field):
    """
    Form fields for dependent instances.

    This field will be displayed for reverse relations where the
    foreign key of this model is required. That is, for related models
    that can not exist unless when related to this one.
    """
    def __init__(self, field, originator, model, request, instance=None, multiple=False, *args, **kwargs):
        self.multiple = multiple
        md = ModelData(model)
        prefix = field.bare_name() + '_' + str(md.content_type().pk)
        if multiple:
            ftt = for_model(request, model, [(field.related_field().bare_name(), originator)])
            ft = forms.modelformset_factory(model, form=ftt)
        else:
            ft = for_model(request, model, [(field.related_field().bare_name(), originator)])
        if request.method == 'POST':
            if multiple:
                fm = ft(request.POST, request.FILES, prefix=prefix, queryset=instance)
            else:
                fm = ft(request.POST, request.FILES, prefix=prefix, instance=instance)
        else:
            if multiple:
                fm = ft(prefix=prefix, queryset=instance)
            else:
                fm = ft(instance=instance, prefix=prefix)
        kwargs['widget'] = rapid_dependent_widget(md, fm, bool(instance), multiple)
        # noinspection PyArgumentList
        super(RapidDependentField, self).__init__(field, *args, **kwargs)
        self.required = False

    def to_python(self, value):
        if self.multiple:
            (f, ii) = value
            if f is None: return None
            if f.is_valid():
                class ValList:
                    def __init__(self, vals):
                        self.vals = vals
                    def save_m2m(self):
                        for v in self.vals:
                            v.save_m2m()
                    def __iter__(self):
                        return self.vals.__iter__()
                objs = [x.save(commit=False) for x in f.forms]
                return ValList([objs[i] for i in ii])
        else:
            if value is None: return None
            if value.is_valid():
                obj = value.save(commit=False)
                obj.save_m2m = value.save_m2m
                return obj
            raise ValidationError(_("Invalid value"), code='invalid')


def for_model(request, model, default_relations=()):
    hasDtWidgets = 'datetimewidget' in settings.INSTALLED_APPS

    default_relations = list(default_relations)
    default_relations_request = request.GET.get('default')
    widgets = []
    default_relations_fields = []
    if default_relations_request:
        default_relations_fields = default_relations_request.split(",")
        default_relations += ((x, int(y)) for (x, y) in (f.split(":") for f in default_relations_fields))
        default_relations_fields = [x for x, y in default_relations]
    for (x, y) in default_relations:
        f = FieldData(getattr(model, x).field, request)
        widgets.append((x, getRapidReadonlyRelation(f.related_model().model, y)))
        default_relations_fields.append(x)
    for f in ModelData(model).local_fields():
        if f.is_relation():
            if force_text(f.bare_name()) not in default_relations_fields and \
            f.related_model().has_permission(request, 'select'):
                widgets.append((f.bare_name(), RapidSelector(f)))
            elif force_text(f.bare_name()) in default_relations_fields:
                pass
        if type(f.field) == models.DateField:
            widgets.append((f.bare_name(), dtwidgets.DateWidget(usel10n = True, bootstrap_version=3)))
        if type(f.field) == models.DateTimeField:
            widgets.append((f.bare_name(), dtwidgets.DateTimeWidget(usel10n = True, bootstrap_version=3)))
        if type(f.field) == models.TimeField:
            widgets.append((f.bare_name(), dtwidgets.TimeWidget(usel10n = True, bootstrap_version=3)))

    #if force_text(model._meta.db_table) == 'testproject_singledepontest1':
    #    import pdb; pdb.set_trace()
    # ModelForm.Meta has attributes with the same names, thus I'll rename them
    form_model = model
    form_widgets = dict(widgets)

    # noinspection PyTypeChecker
    class CForm(forms.ModelForm):
        def __init__(self, *args, **kwargs):

            # Sets alternative data:
            initial = kwargs.get('initial', {})
            for (k, v) in default_relations:
                initial[k] = v
            if initial:
                kwargs['initial'] = initial
            instance = kwargs.get('instance')
            for n, fd in ModelData(model).rapid_alternative_data():
                ct = ModelData(model).field_by_name(fd.ct_field).field
                fk = ModelData(model).field_by_name(fd.fk_field).field
                # noinspection PyTypeChecker
                fl = RapidAlternativesField(n, ct.alternatives, ct.name, self, request, instance)
                # noinspection PyArgumentList
                type(self.__class__).__setattr__(self.__class__, n, fl)
                nd = collections.OrderedDict()
                for k, v in self.__class__.base_fields.items():
                    if k == fk.name:
                        nd[n] = fl
                    else:
                        nd[k] = v
                self.__class__.base_fields = nd

            # Sets fields for reverse relations:
            for f in ModelData(model).related_fields():
                if f.is_existential_dependency():
                    md = f.related_model().model
                    ft = {f.related_field().bare_name(): instance}
                    dt = md.objects.filter(**ft)
                    if f.is_multiple():
                        fl = RapidDependentField(f, instance, md, request, dt, True)
                    else:
                        o = dt[0] if dt else None
                        fl = RapidDependentField(f, instance, md, request,
                                                 o, False)
                    self.__class__.base_fields[f.bare_name()] = fl

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

        @transaction.atomic
        def save(self, commit=True):

            if not commit:
                return super(CForm, self).save(commit)
            else:
                obj = super(CForm, self).save(commit=False)

                # Saving alternative data:
                for n, fd in ModelData(model).rapid_alternative_data():
                    if self.instance:
                        old_t = getattr(self.instance, fd.ct_field)
                        new_t = getattr(obj, fd.ct_field)
                        if old_t != new_t:
                            getattr(self.instance, fd.bare_name).delete()
                    fob = self.cleaned_data[n]
                    fob.save()
                    if hasattr(fob, 'save_m2m'):
                        fob.save_m2m()
                    setattr(obj, fd.fk_field, fob.pk)

                obj.save()

                # Saving reverse relations:
                for f in ModelData(model).related_fields():
                    if f.is_existential_dependency():
                        fob = self.cleaned_data[f.bare_name()]
                        ft = {f.related_field().bare_name(): obj}
                        if fob:
                            if f.is_multiple():
                                ex = {'pk__in': [ob.pk for ob in fob if ob.pk]}
                                f.related_model().model.objects.filter(**ft).exclude(**ex).delete()
                                for ob in fob:
                                    setattr(ob, f.related_field().bare_name(), obj)
                                    ob.save()
                                    if hasattr(ob, 'save_m2m'):
                                        ob.save_m2m()
                            else:
                                ex = {'pk__exact': fob.pk}
                                f.related_model().model.objects.filter(**ft).exclude(**ex).delete()
                                setattr(fob, f.related_field().bare_name(), obj)
                                fob.save()
                                if hasattr(fob, 'save_m2m'):
                                    fob.save_m2m()
                        else:
                            f.related_model().model.objects.filter(**ft).delete()


                self.save_m2m()
                return obj

        class Meta(object):
            model = form_model
            fields = '__all__'
            widgets = form_widgets

    return CForm