from django import forms
from django.contrib.admin.widgets import AutocompleteSelect
from django.db import transaction
from django.db.models.deletion import Collector
from django.forms import inlineformset_factory
from django.urls import reverse

from django_summernote.widgets import SummernoteWidget
from tabimport import FileFactory, UnsupportedFileFormat

from .models import Corporation, Period, Section, Student, StudentFile


class StudentImportForm(forms.Form):
    upload = forms.FileField()

    def __init__(self, file_label='Fichier', mandatory_headers=None, **kwargs):
        super().__init__(**kwargs)
        self.fields['upload'].label = file_label
        self.mandatory_headers = mandatory_headers

    def clean_upload(self):
        f = self.cleaned_data['upload']
        try:
            imp_file = FileFactory(f)
        except UnsupportedFileFormat as e:
            raise forms.ValidationError("Erreur: %s" % e)
        # Check needed headers are present
        headers = imp_file.get_headers()
        missing = set(self.mandatory_headers) - set(headers)
        if missing:
            raise forms.ValidationError("Erreur: il manque les colonnes %s" % (
                ", ".join(missing)))
        return f


class PeriodForm(forms.Form):
    section = forms.ModelChoiceField(queryset=Section.objects.all())
    period = forms.ModelChoiceField(queryset=None)

    def __init__(self, data, *args, **kwargs):
        pass


class UploadHPFileForm(forms.Form):
    upload = forms.FileField(label='Fichier HyperPlanning')


class UploadReportForm(forms.Form):
    semester = forms.ChoiceField(label='Semestre', choices=(('1', '1'), ('2', '2')), required=True)
    upload = forms.FileField(label='Bulletins CLOEE (pdf)')


class EmailBaseForm(forms.Form):
    sender = forms.CharField(widget=forms.HiddenInput())
    to = forms.CharField(widget=forms.TextInput(attrs={'size': '60'}))
    cci = forms.CharField(widget=forms.TextInput(attrs={'size': '60'}))
    subject = forms.CharField(widget=forms.TextInput(attrs={'size': '60'}))
    message = forms.CharField(widget=forms.Textarea(attrs={'rows': 20, 'cols': 120}))



class CorpAutocompleteSelect(AutocompleteSelect):
    model = Corporation

    def __init__(self, **kwargs):
        super().__init__(None, None, **kwargs)

    def get_url(self):
        return reverse(self.url_name % ('admin', self.model._meta.app_label, self.model._meta.model_name))


class CorporationMergeForm(forms.Form):
    corp_merge_from = forms.ModelChoiceField(
        label="L'institution", queryset=Corporation.objects.filter(archived=False),
        widget=CorpAutocompleteSelect
    )
    corp_merge_to = forms.ModelChoiceField(
        label="Sera fusionnée dans", queryset=Corporation.objects.filter(archived=False),
        widget=CorpAutocompleteSelect
    )

    def merge_corps(self):
        def check_no_links(instance):
            collector = Collector(using='default')
            collector.collect(instance._meta.model.objects.filter(pk=instance.pk))
            if len(collector.data) > 1:
                raise Exception(collector.data)

        with transaction.atomic():
            # Try first to merge corpcontacts with same name
            merge_to_contacts = {
                (cont.last_name, cont.first_name): cont
                for cont in self.cleaned_data['corp_merge_to'].corpcontact_set.all()
            }
            for contact in self.cleaned_data['corp_merge_from'].corpcontact_set.all():
                ckey = (contact.last_name, contact.first_name)
                if ckey in merge_to_contacts:
                    # Merge contacts
                    for rel in (
                            'availability_set', 'candidate_set', 'rel_expert', 'rel_mentor',
                            'rel_supervisor', 'student_set', 'supervisionbill_set'):
                        relation = getattr(contact, rel)
                        relation.all().update(**{relation.field.name: merge_to_contacts[ckey]})
                    check_no_links(contact)
                    contact.delete()
            # Merge corporation now
            self.cleaned_data['corp_merge_from'].corpcontact_set.all(
                ).update(corporation=self.cleaned_data['corp_merge_to'])
            self.cleaned_data['corp_merge_from'].availability_set.all(
                ).update(corporation=self.cleaned_data['corp_merge_to'])
            self.cleaned_data['corp_merge_from'].student_set.all(
                ).update(corporation=self.cleaned_data['corp_merge_to'])
            self.cleaned_data['corp_merge_from'].candidate_set.all(
                ).update(corporation=self.cleaned_data['corp_merge_to'])
            check_no_links(self.cleaned_data['corp_merge_from'])
            self.cleaned_data['corp_merge_from'].delete()


class StudentCommentForm(forms.ModelForm):
    class Meta:
        model = Student
        fields = ('mc_comment',)
        widgets = {
            'mc_comment': SummernoteWidget,
        }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        FilesFormSet = inlineformset_factory(self._meta.model, StudentFile, fields='__all__', extra=1)
        self.files_fset = FilesFormSet(
            instance=self.instance, data=kwargs.get('data'), files=kwargs.get('files')
        )

    def is_valid(self):
        return all([super().is_valid(), self.files_fset.is_valid()])

    def save(self, **kwargs):
        obj = super().save(**kwargs)
        self.files_fset.save()
        return obj