# coding=utf-8

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

from django.contrib.contenttypes.models import ContentType
from django.core.exceptions import ValidationError
from django.db import transaction

import gettext
from django.utils.encoding import force_text

_ = gettext.gettext

__author__ = 'marcos'

import collections

from django import forms

from rapid.widgets import RapidSelector, RapidRelationReadOnly, rapid_alternatives_widget
from rapid.wrappers import FieldData, ModelData


class RapidAlternativesField(forms.Field):
    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')


def for_model(request, model, default_relations=()):
    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, RapidRelationReadOnly(f.related_model())))
    for f in ModelData(model).local_fields():
        if f.is_relation() and force_text(f.bare_name()) not in default_relations_fields:
            if f.related_model().has_permission(request, 'select'):
                widgets.append((f.bare_name(), RapidSelector(f)))
    # 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):
            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
            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)
                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()
                self.save_m2m()
                return obj

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

    return CForm