# Copyright (C) 2020 by Animath
# SPDX-License-Identifier: GPL-3.0-or-later

import os

from django.conf import settings
from django.contrib.auth.mixins import LoginRequiredMixin
from django.contrib.auth.models import User
from django.core.exceptions import PermissionDenied, ValidationError
from django.db import transaction
from django.db.models import Q
from django.http import FileResponse, Http404
from django.shortcuts import redirect, resolve_url
from django.urls import reverse_lazy
from django.utils.http import urlsafe_base64_decode
from django.utils.translation import gettext_lazy as _
from django.views.generic import CreateView, DetailView, RedirectView, TemplateView, UpdateView, View
from django_tables2 import SingleTableView
from magic import Magic
from participation.models import Passage, Solution, Synthesis
from tfjm.tokens import email_validation_token
from tfjm.views import AdminMixin, UserMixin, VolunteerMixin

from .forms import AddOrganizerForm, AdminRegistrationForm, CoachRegistrationForm, HealthSheetForm, \
    ParentalAuthorizationForm, PhotoAuthorizationForm, SignupForm, StudentRegistrationForm, UserForm, \
    VolunteerRegistrationForm
from .models import ParticipantRegistration, Registration, StudentRegistration
from .tables import RegistrationTable


class SignupView(CreateView):
    """
    Signup, as a participant or a coach.
    """
    model = User
    form_class = SignupForm
    template_name = "registration/signup.html"
    extra_context = dict(title=_("Sign up"))

    def get_context_data(self, **kwargs):
        context = super().get_context_data()

        context["student_registration_form"] = StudentRegistrationForm(self.request.POST or None)
        context["coach_registration_form"] = CoachRegistrationForm(self.request.POST or None)

        del context["student_registration_form"].fields["team"]
        del context["student_registration_form"].fields["email_confirmed"]
        del context["coach_registration_form"].fields["team"]
        del context["coach_registration_form"].fields["email_confirmed"]

        return context

    @transaction.atomic
    def form_valid(self, form):
        role = form.cleaned_data["role"]
        if role == "participant":
            registration_form = StudentRegistrationForm(self.request.POST)
        else:
            registration_form = CoachRegistrationForm(self.request.POST)
        del registration_form.fields["team"]
        del registration_form.fields["email_confirmed"]

        if not registration_form.is_valid():
            return self.form_invalid(form)

        ret = super().form_valid(form)
        registration = registration_form.instance
        registration.user = form.instance
        registration.save()
        registration.send_email_validation_link()

        return ret

    def get_success_url(self):
        return reverse_lazy("registration:email_validation_sent")


class AddOrganizerView(VolunteerMixin, CreateView):
    model = User
    form_class = AddOrganizerForm
    template_name = "registration/add_organizer.html"
    extra_context = dict(title=_("Add organizer"))

    def get_context_data(self, **kwargs):
        context = super().get_context_data()

        context["volunteer_registration_form"] = VolunteerRegistrationForm(self.request.POST or None)
        context["admin_registration_form"] = AdminRegistrationForm(self.request.POST or None)

        del context["volunteer_registration_form"].fields["email_confirmed"]
        del context["admin_registration_form"].fields["email_confirmed"]

        if not self.request.user.registration.is_admin:
            del context["form"].fields["type"]
            del context["admin_registration_form"]

        return context

    @transaction.atomic
    def form_valid(self, form):
        role = form.cleaned_data["type"]
        if role == "admin":
            registration_form = AdminRegistrationForm(self.request.POST)
        else:
            registration_form = VolunteerRegistrationForm(self.request.POST)
        del registration_form.fields["email_confirmed"]

        if not registration_form.is_valid():
            return self.form_invalid(form)

        ret = super().form_valid(form)
        registration = registration_form.instance
        registration.user = form.instance
        registration.save()
        registration.send_email_validation_link()

        return ret

    def get_success_url(self):
        return reverse_lazy("registration:email_validation_sent")


class UserValidateView(TemplateView):
    """
    A view to validate the email address.
    """
    title = _("Email validation")
    template_name = 'registration/email_validation_complete.html'
    extra_context = dict(title=_("Validate email"))

    def get(self, *args, **kwargs):
        """
        With a given token and user id (in params), validate the email address.
        """
        assert 'uidb64' in kwargs and 'token' in kwargs

        self.validlink = False
        user = self.get_user(kwargs['uidb64'])
        token = kwargs['token']

        # Validate the token
        if user is not None and email_validation_token.check_token(user, token):
            self.validlink = True
            user.registration.email_confirmed = True
            user.registration.save()
        return self.render_to_response(self.get_context_data(), status=200 if self.validlink else 400)

    def get_user(self, uidb64):
        """
        Get user from the base64-encoded string.
        """
        try:
            # urlsafe_base64_decode() decodes to bytestring
            uid = urlsafe_base64_decode(uidb64).decode()
            user = User.objects.get(pk=uid)
        except (TypeError, ValueError, OverflowError, User.DoesNotExist, ValidationError):
            user = None
        return user

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['user_object'] = self.get_user(self.kwargs["uidb64"])
        context['login_url'] = resolve_url(settings.LOGIN_URL)
        if self.validlink:
            context['validlink'] = True
        else:
            context.update({
                'title': _('Email validation unsuccessful'),
                'validlink': False,
            })
        return context


class UserValidationEmailSentView(TemplateView):
    """
    Display the information that the validation link has been sent.
    """
    template_name = 'registration/email_validation_email_sent.html'
    extra_context = dict(title=_('Email validation email sent'))


class UserResendValidationEmailView(LoginRequiredMixin, DetailView):
    """
    Rensend the email validation link.
    """
    model = User
    extra_context = dict(title=_("Resend email validation link"))

    def get(self, request, *args, **kwargs):
        user = self.get_object()
        user.registration.send_email_validation_link()
        return redirect('registration:email_validation_sent')


class MyAccountDetailView(LoginRequiredMixin, RedirectView):
    """
    Redirect to our own profile detail page.
    """
    def get_redirect_url(self, *args, **kwargs):
        return reverse_lazy("registration:user_detail", args=(self.request.user.pk,))


class UserDetailView(UserMixin, DetailView):
    """
    Display the detail about a user.
    """

    model = User
    context_object_name = "user_object"
    template_name = "registration/user_detail.html"

    def dispatch(self, request, *args, **kwargs):
        me = request.user
        if not me.is_authenticated:
            return self.handle_no_permission()
        user = self.get_object()
        if user == me or me.registration.is_admin or me.registration.is_volunteer \
                and user.registration.participates and user.registration.team \
                and user.registration.team.participation.tournament in user.registration.organized_tournaments.all() \
                or user.registration.is_volunteer and me.registration.is_volunteer \
                and me.registration.interesting_tournaments.intersection(user.registration.intersting_tournaments):
            return super().dispatch(request, *args, **kwargs)
        raise PermissionDenied

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context["title"] = _("Detail of user {user}").format(user=str(self.object.registration))
        return context


class UserListView(AdminMixin, SingleTableView):
    """
    Display the list of all registered users.
    """
    model = Registration
    table_class = RegistrationTable
    template_name = "registration/user_list.html"


class UserUpdateView(UserMixin, UpdateView):
    """
    Update the detail about a user and its registration.
    """
    model = User
    form_class = UserForm
    template_name = "registration/update_user.html"

    def dispatch(self, request, *args, **kwargs):
        if not self.request.user.is_authenticated or \
                not self.request.user.registration.is_admin and self.request.user != self.get_object():
            return self.handle_no_permission()
        return super().dispatch(request, *args, **kwargs)

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        user = self.get_object()
        context["title"] = _("Update user {user}").format(user=str(self.object.registration))
        context["registration_form"] = user.registration.form_class(data=self.request.POST or None,
                                                                    instance=self.object.registration)
        if not self.request.user.registration.is_admin:
            if "team" in context["registration_form"].fields:
                del context["registration_form"].fields["team"]
            del context["registration_form"].fields["email_confirmed"]
        return context

    @transaction.atomic
    def form_valid(self, form):
        user = form.instance
        registration_form = user.registration.form_class(data=self.request.POST or None,
                                                         instance=self.object.registration)
        if not self.request.user.registration.is_admin:
            if "team" in registration_form.fields:
                del registration_form.fields["team"]
            del registration_form.fields["email_confirmed"]

        if not registration_form.is_valid():
            return self.form_invalid(form)

        registration_form.save()
        return super().form_valid(form)

    def get_success_url(self):
        return reverse_lazy("registration:user_detail", args=(self.object.pk,))


class UserUploadPhotoAuthorizationView(UserMixin, UpdateView):
    """
    A participant can send its photo authorization.
    """
    model = StudentRegistration
    form_class = PhotoAuthorizationForm
    template_name = "registration/upload_photo_authorization.html"
    extra_context = dict(title=_("Upload photo authorization"))

    def dispatch(self, request, *args, **kwargs):
        if not self.request.user.is_authenticated or \
                not self.request.user.registration.is_admin and self.request.user != self.get_object().user:
            return self.handle_no_permission()
        return super().dispatch(request, *args, **kwargs)

    @transaction.atomic
    def form_valid(self, form):
        old_instance = StudentRegistration.objects.get(pk=self.object.pk)
        if old_instance.photo_authorization:
            old_instance.photo_authorization.delete()
        return super().form_valid(form)

    def get_success_url(self):
        return reverse_lazy("registration:user_detail", args=(self.object.user.pk,))


class UserUploadHealthSheetView(UserMixin, UpdateView):
    """
    A participant can send its health sheet.
    """
    model = StudentRegistration
    form_class = HealthSheetForm
    template_name = "registration/upload_health_sheet.html"
    extra_context = dict(title=_("Upload health sheet"))

    def dispatch(self, request, *args, **kwargs):
        if not self.request.user.is_authenticated or \
                not self.request.user.registration.is_admin and self.request.user != self.get_object().user:
            return self.handle_no_permission()
        return super().dispatch(request, *args, **kwargs)

    @transaction.atomic
    def form_valid(self, form):
        old_instance = StudentRegistration.objects.get(pk=self.object.pk)
        if old_instance.health_sheet:
            old_instance.health_sheet.delete()
        return super().form_valid(form)

    def get_success_url(self):
        return reverse_lazy("registration:user_detail", args=(self.object.user.pk,))


class UserUploadParentalAuthorizationView(UserMixin, UpdateView):
    """
    A participant can send its parental authorization.
    """
    model = StudentRegistration
    form_class = ParentalAuthorizationForm
    template_name = "registration/upload_parental_authorization.html"
    extra_context = dict(title=_("Upload parental authorization"))

    def dispatch(self, request, *args, **kwargs):
        if not self.request.user.is_authenticated or \
                not self.request.user.registration.is_admin and self.request.user != self.get_object().user:
            return self.handle_no_permission()
        return super().dispatch(request, *args, **kwargs)

    @transaction.atomic
    def form_valid(self, form):
        old_instance = StudentRegistration.objects.get(pk=self.object.pk)
        if old_instance.parental_authorization:
            old_instance.parental_authorization.delete()
        return super().form_valid(form)

    def get_success_url(self):
        return reverse_lazy("registration:user_detail", args=(self.object.user.pk,))


class PhotoAuthorizationView(LoginRequiredMixin, View):
    """
    Display the sent photo authorization.
    """
    def get(self, request, *args, **kwargs):
        filename = kwargs["filename"]
        path = f"media/authorization/photo/{filename}"
        if not os.path.exists(path):
            raise Http404
        student = ParticipantRegistration.objects.get(photo_authorization__endswith=filename)
        user = request.user
        if not (student.user == user or user.registration.is_admin or user.registration.is_volunteer and student.team
                and student.team.participation.tournament in user.registration.organized_tournaments.all()):
            raise PermissionDenied
        # Guess mime type of the file
        mime = Magic(mime=True)
        mime_type = mime.from_file(path)
        ext = mime_type.split("/")[1].replace("jpeg", "jpg")
        # Replace file name
        true_file_name = _("Photo authorization of {student}.{ext}").format(student=str(student), ext=ext)
        return FileResponse(open(path, "rb"), content_type=mime_type, filename=true_file_name)


class HealthSheetView(LoginRequiredMixin, View):
    """
    Display the sent health sheet.
    """
    def get(self, request, *args, **kwargs):
        filename = kwargs["filename"]
        path = f"media/authorization/health/{filename}"
        if not os.path.exists(path):
            raise Http404
        student = ParticipantRegistration.objects.get(health_sheet__endswith=filename)
        user = request.user
        if not (student.user == user or user.registration.is_admin or user.registration.is_volunteer and student.team
                and student.team.participation.tournament in user.registration.organized_tournaments.all()):
            raise PermissionDenied
        # Guess mime type of the file
        mime = Magic(mime=True)
        mime_type = mime.from_file(path)
        ext = mime_type.split("/")[1].replace("jpeg", "jpg")
        # Replace file name
        true_file_name = _("Health sheet of {student}.{ext}").format(student=str(student), ext=ext)
        return FileResponse(open(path, "rb"), content_type=mime_type, filename=true_file_name)


class ParentalAuthorizationView(LoginRequiredMixin, View):
    """
    Display the sent parental authorization.
    """
    def get(self, request, *args, **kwargs):
        filename = kwargs["filename"]
        path = f"media/authorization/parental/{filename}"
        if not os.path.exists(path):
            raise Http404
        student = StudentRegistration.objects.get(parental_authorization__endswith=filename)
        user = request.user
        if not (student.user == user or user.registration.is_admin or user.registration.is_volunteer and student.team
                and student.team.participation.tournament in user.registration.organized_tournaments.all()):
            raise PermissionDenied
        # Guess mime type of the file
        mime = Magic(mime=True)
        mime_type = mime.from_file(path)
        ext = mime_type.split("/")[1].replace("jpeg", "jpg")
        # Replace file name
        true_file_name = _("Parental authorization of {student}.{ext}").format(student=str(student), ext=ext)
        return FileResponse(open(path, "rb"), content_type=mime_type, filename=true_file_name)


class SolutionView(LoginRequiredMixin, View):
    """
    Display the sent solution.
    """
    def get(self, request, *args, **kwargs):
        filename = kwargs["filename"]
        path = f"media/solutions/{filename}"
        if not os.path.exists(path):
            raise Http404
        solution = Solution.objects.get(file__endswith=filename)
        user = request.user
        if not (user.registration.is_admin or user.registration.is_volunteer
                and Passage.objects.filter(Q(pool__juries=user.registration)
                                           | Q(pool__tournament__in=user.registration.organized_tournaments.all()),
                                           defender=solution.participation,
                                           solution_number=solution.problem).exists()
                or user.registration.participates and user.registration.team
                and Passage.objects.filter(Q(defender=user.registration.team.participation)
                                           | Q(opponent=user.registration.team.participation)
                                           | Q(reporter=user.registration.team.participation),
                                           defender=solution.participation,
                                           solution_number=solution.problem).exists()):
            raise PermissionDenied
        # Guess mime type of the file
        mime = Magic(mime=True)
        mime_type = mime.from_file(path)
        ext = mime_type.split("/")[1].replace("jpeg", "jpg")
        # Replace file name
        true_file_name = str(solution) + f".{ext}"
        return FileResponse(open(path, "rb"), content_type=mime_type, filename=true_file_name)


class SynthesisView(LoginRequiredMixin, View):
    """
    Display the sent synthesis.
    """
    def get(self, request, *args, **kwargs):
        filename = kwargs["filename"]
        path = f"media/syntheses/{filename}"
        if not os.path.exists(path):
            raise Http404
        synthesis = Synthesis.objects.get(file__endswith=filename)
        user = request.user
        if not (user.registration.is_admin or user.registration.is_volunteer
                and (user.registration in synthesis.passage.pool.juries.all()
                     or user.registration in synthesis.passage.pool.tournament.organizers.all())
                or user.registration.participates and user.registration.team == synthesis.participation.team):
            raise PermissionDenied
        # Guess mime type of the file
        mime = Magic(mime=True)
        mime_type = mime.from_file(path)
        ext = mime_type.split("/")[1].replace("jpeg", "jpg")
        # Replace file name
        true_file_name = str(synthesis) + f".{ext}"
        return FileResponse(open(path, "rb"), content_type=mime_type, filename=true_file_name)


class UserImpersonateView(LoginRequiredMixin, RedirectView):
    """
    An administrator can log in through this page as someone else, and act as this other person.
    """

    def dispatch(self, request, *args, **kwargs):
        if self.request.user.registration.is_admin:
            if not User.objects.filter(pk=kwargs["pk"]).exists():
                raise Http404
            session = request.session
            session["admin"] = request.user.pk
            session["_fake_user_id"] = kwargs["pk"]
        return super().dispatch(request, *args, **kwargs)

    def get_redirect_url(self, *args, **kwargs):
        return reverse_lazy("registration:user_detail", args=(kwargs["pk"],))


class ResetAdminView(LoginRequiredMixin, View):
    """
    Return to admin view, clear the session field that let an administrator to log in as someone else.
    """

    def dispatch(self, request, *args, **kwargs):
        user = request.user
        if not user.is_authenticated:
            return self.handle_no_permission()
        if "_fake_user_id" in request.session:
            del request.session["_fake_user_id"]
        return redirect(request.GET.get("path", reverse_lazy("index")))