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
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 django.utils.html import strip_tags

from input.utils.mail import collect_attachment_paths, attach_files, build_email

from .forms import (
    BaseApplicationForm,
    ProjectForm,
    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_PROJ,
    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)


PROJECT_FUNDING = [
    ApplicationType(TYPE_PROJ, 'projektfoerderung', ProjectForm),
]

SERVICES = [
    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),
]

TYPES = {info.path: info for info in PROJECT_FUNDING + SERVICES}


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 = {'services': SERVICES}


class ProjectFundingInfoView(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']

        if type_info := TYPES.get(type_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.
        """

        data = self.prepare_data(form)
        obj = self.save_obj(form, data)

        if response := self.send_mail(obj, data):
            return response

        return done(self.request)

    def prepare_data(self, form):
        # Collect cleaned data and mark the current type

        data = {**form.cleaned_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'

        return data

    def save_obj(self, form, data):
        # 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()

        return modell

    def send_mail(self, obj, data):
        # Prepare minimal mail context and send mails

        type_label_html = self.type_info.label
        type_label_plain = strip_tags(type_label_html)

        data['pk'] = obj.pk
        data['url_prefix'] = settings.EMAIL_URL_PREFIX
        data['type_label'] = type_label_html

        context = {'data': data}

        applicant_name = self.get_recipient_name(obj, data)
        applicant_subject = 'Deine Förderanfrage bei Wikimedia Deutschland'

        staff_subject = f'Anfrage {type_label_plain} von {applicant_name}'

        try:
            self.send_email('applicant', 'ifg_volunteer_mail', applicant_subject, data['email'], context)
            self.send_email('staff', 'if_mail', staff_subject, settings.IF_EMAIL, context)
        except BadHeaderError:
            obj.delete()
            return HttpResponse('Invalid header found. Data not saved!')
        except SMTPException:
            obj.delete()
            return HttpResponse('Error in sending mails (probably wrong address?). Data not saved!')

    def send_email(self, kind, template_name, subject, recipient, context, *, fail_silently=False):
        email = build_email(template_name, context, subject, recipient)
        applicant_files = collect_attachment_paths(kind, self.type_code)

        attach_files(email, applicant_files)

        return email.send(fail_silently)

    @staticmethod
    def get_recipient_name(obj, data):
        for field in 'username', 'realname', 'email':
            if name := getattr(obj, field, None) or data.get(field):
                return name

        return 'Unbekannt'