from smtplib import SMTPException
from typing import NamedTuple

from django.shortcuts import render
from django.http import HttpResponse, Http404
from django.utils.functional import cached_property
from django.utils.safestring import mark_safe
from django.core.mail import BadHeaderError, EmailMultiAlternatives
from django.template.loader import get_template
from django.conf import settings
from django.contrib.auth.decorators import login_required
from django.views.generic import TemplateView
from django.views.generic.edit import FormView

from .forms import (
    BaseApplicationForm,
    LibraryForm,
    ELiteratureForm,
    SoftwareForm,
    IFGForm,
    LiteratureForm,
    TravelForm,
    EmailForm,
    ListForm,
    BusinessCardForm,
)
from .models import (
    MODELS,
    LIBRARY_TYPES,
    TYPE_CHOICES,
    TYPE_BIB,
    TYPE_ELIT,
    TYPE_IFG,
    TYPE_LIT,
    TYPE_LIST,
    TYPE_MAIL,
    TYPE_SOFT,
    TYPE_TRAV,
    TYPE_VIS,
)

HELP_TEXTS = {
    TYPE_IFG: {
        'notes': (
            'Bitte gib an, wie die gewonnenen Informationen den<br>'
            'Wikimedia-Projekten zugute kommen sollen.'
        )
    },
    TYPE_MAIL: {
        'domain': (
            'Mit welcher Domain, bzw. für welches Wikimedia-Projekt,<br>'
            'möchtest du eine Mailadresse beantragen?'
        )
    },
    TYPE_LIT: {
        'notes': 'Bitte gib an, wofür du die Literatur verwenden möchtest.'
    },
    TYPE_LIST: {
        'domain': (
            'Mit welcher Domain, bzw. für welches Wikimedia-Projekt,<br>'
            'möchtest du eine Mailingliste beantragen?'
        )
    },
}


class ApplicationType(NamedTuple):
    code: str
    path: str
    form_class: type[BaseApplicationForm]

    @property
    def label(self):
        return TYPE_CHOICES[self.code]

    @property
    def help_texts(self):
        return HELP_TEXTS.get(self.code)


TYPES = [
    ApplicationType(TYPE_BIB, 'bibliotheksstipendium', LibraryForm),
    ApplicationType(TYPE_ELIT, 'eliteraturstipendium', ELiteratureForm),
    ApplicationType(TYPE_MAIL, 'email', EmailForm),
    ApplicationType(TYPE_IFG, 'ifg', IFGForm),
    ApplicationType(TYPE_LIT, 'literaturstipendium', LiteratureForm),
    ApplicationType(TYPE_LIST, 'mailingliste', ListForm),
    ApplicationType(TYPE_TRAV, 'reisekosten', TravelForm),
    ApplicationType(TYPE_SOFT, 'softwarestipendium', SoftwareForm),
    ApplicationType(TYPE_VIS, 'visitenkarten', BusinessCardForm),
]


def auth_deny(choice, pk, auth):
    if choice not in MODELS:
        return HttpResponse(f'ERROR! UNKNOWN CHOICE TYPE! {choice}')

    MODELS[choice].set_granted(pk, auth)


@login_required
def export(request):
    '''export the project database to a csv'''
    return HttpResponse('WE WANT CSV!')


@login_required
def authorize(request, choice, pk):
    '''If IF grant a support they click a link in a mail which leads here.
    We write the granted field in the database here and set a timestamp.'''

    if ret := auth_deny(choice, pk, True):
        return ret
    else:
        return HttpResponse(f'AUTHORIZED! choice: {choice}, pk: {pk}')


@login_required
def deny(request, choice, pk):
    '''If IF denies a support they click a link in a mail which leads here
    We write the granted field in the database here.'''

    if ret := auth_deny(choice, pk, False):
        return ret
    else:
        return HttpResponse(f'DENIED! choice: {choice}, pk: {pk}')


def done(request):
    return HttpResponse(
        'Deine Anfrage wurde gesendet. Du erhältst in Kürze eine E-Mail-Benachrichtigung mit deinen Angaben. Für alle Fragen kontaktiere bitte das Team Communitys und Engagement unter community@wikimedia.de.')


def index(request):
    return render(request, 'input/index.html')


class ApplicationStartView(TemplateView):
    template_name = 'input/forms/extern.html'
    extra_context = {'types': TYPES}


class ProjectInfoView(TemplateView):
    template_name = 'input/info_project_funding_gt_1000.html'


class ApplicationView(FormView):
    """
    View for all application types.

    - Renders the generic form template.
    - Handles saving the submitted form to the database.
    - Adds extra fields from the session or request type if needed.
    - Applies optional help_text overrides for certain fields.
    - Sends confirmation mail to the applicant.
    - Sends notification mail to the internal IF address.
    - Returns the "done" response after successful processing.
    """

    template_name = 'input/forms/form_generic.html'

    @cached_property
    def type_info(self) -> ApplicationType:
        type_path = self.kwargs['type']

        for type_info in TYPES:
            if type_path == type_info.path:
                return type_info

        raise Http404(f'"{type_path}" existiert nicht.')

    @property
    def type_code(self):
        return self.type_info.code

    @property
    def form_class(self):
        return self.type_info.form_class

    def get_context_data(self, **kwargs):
        return super().get_context_data(**kwargs, type_label=self.type_info.label)

    def get_form(self, form_class=None):
        """Return the form instance and inject custom help_texts if defined for this type."""
        form = super().get_form(form_class)

        # Apply help_text overrides if defined for this type_code
        if help_texts := self.type_info.help_texts:
            for field, text in help_texts.items():
                if field in form.fields:
                    form.fields[field].help_text = mark_safe(text)

        return form

    def form_valid(self, form):
        """
        Process a valid form submission:
        - Enrich form data (e.g., set type_code, handle special rules).
        - Save the model instance and related data.
        - Send confirmation and notification mails.
        - Return the "done" response.
        """

        # Collect cleaned data and mark the current type
        data = form.cleaned_data.copy()
        data['choice'] = self.type_code

        # Special rule for literature applications
        if self.type_code == TYPE_LIT and data.get('selfbuy') == 'TRUE':
            data['selfbuy_give_data'] = 'False'

        # Save model instance
        modell = form.save(commit=False)

        # Username from session if present
        if user := self.request.session.get('user'):
            modell.username = user.get('username')

        # Copy common fields if provided by the form
        if 'realname' in data:
            modell.realname = data['realname']
        if 'email' in data:
            modell.email = data['email']

        # Set model.type for specific request types
        if self.type_code in LIBRARY_TYPES:
            modell.type = self.type_code

        # Literature-specific extra field
        if self.type_code == TYPE_LIT and 'selfbuy_give_data' in data:
            modell.selfbuy_give_data = data['selfbuy_give_data']

        modell.save()
        if hasattr(form, 'save_m2m'):
            form.save_m2m()

        # Prepare minimal mail context and send mails
        data['pk'] = modell.pk
        data['url_prefix'] = settings.EMAIL_URL_PREFIX
        data['type_label'] = self.type_info.label
        context = {'data': data}

        try:
            # Mail to applicant
            txt1 = get_template('input/ifg_volunteer_mail.txt').render(context)
            html1 = get_template('input/ifg_volunteer_mail.html').render(context)
            msg1 = EmailMultiAlternatives(
                'Formular ausgefüllt', txt1, settings.IF_EMAIL, [data['email']]
            )
            msg1.attach_alternative(html1, 'text/html')
            msg1.send()

            # Mail to IF
            txt2 = get_template('input/if_mail.txt').render(context)
            html2 = get_template('input/if_mail.html').render(context)
            msg2 = EmailMultiAlternatives(
                'Formular ausgefüllt', txt2, settings.IF_EMAIL, [settings.IF_EMAIL]
            )
            msg2.attach_alternative(html2, 'text/html')
            msg2.send()

        except BadHeaderError:
            modell.delete()
            return HttpResponse('Invalid header found. Data not saved!')
        except SMTPException:
            modell.delete()
            return HttpResponse('Error in sending mails (probably wrong adress?). Data not saved!')

        return done(self.request)