import uuid

from django.core.exceptions import ImproperlyConfigured
from django.core.paginator import Paginator
from django.db.models import QuerySet
from django.http import Http404, HttpResponse, HttpResponseBadRequest
from django.urls import reverse
from django.views.generic.detail import DetailView
from django.views.generic.edit import CreateView, DeleteView, UpdateView
from django.views.generic.list import ListView
from rest_framework.parsers import FormParser


class AbortSave(Exception):
    pass


class RestrictedViewMixin:
    """
    This mixin overrides two helpers in order to pass the user object to the filters.
    get_queryset alters the objects returned for list views.
    get_form_kwargs passes the request object to the form class. Remaining permissions
    checks are in forms.py
    """

    allow_empty = True
    queryset = None
    model = None
    paginate_by = None
    paginate_orphans = 0
    context_object_name = None
    paginator_class = Paginator
    page_kwarg = "page"
    ordering = None

    def set_extra_args(self, user):
        """
        This function is overriden to filter the objects by the requesting user.
        """
        self.extra_permission_args = {}

    def get_queryset(self, **kwargs):
        """
        This function is overriden to filter the objects by the requesting user.
        """
        self.set_extra_args(self.request.user)
        if self.queryset is not None:
            queryset = self.queryset
            if isinstance(queryset, QuerySet):
                # queryset = queryset.all()
                queryset = queryset.filter(
                    user=self.request.user, **self.extra_permission_args
                )
        elif self.model is not None:
            queryset = self.model._default_manager.filter(
                user=self.request.user, **self.extra_permission_args
            )
        else:
            raise ImproperlyConfigured(
                "%(cls)s is missing a QuerySet. Define "
                "%(cls)s.model, %(cls)s.queryset, or override "
                "%(cls)s.get_queryset()." % {"cls": self.__class__.__name__}
            )
        if hasattr(self, "get_ordering"):
            ordering = self.get_ordering()
            if ordering:
                if isinstance(ordering, str):
                    ordering = (ordering,)
                queryset = queryset.order_by(*ordering)

        return queryset

    def get_form_kwargs(self):
        """Passes the request object to the form class.
        This is necessary to only display members that belong to a given user"""

        kwargs = super().get_form_kwargs()
        kwargs["request"] = self.request
        return kwargs


class ObjectNameMixin(object):
    def __init__(self, *args, **kwargs):
        if self.model is None:
            self.title = self.context_object_name.title()
            self.title_singular = self.context_object_name_singular.title()
        else:
            self.title_singular = self.model._meta.verbose_name.title()  # Hook
            self.context_object_name_singular = self.title_singular.lower()  # hook
            self.title = self.model._meta.verbose_name_plural.title()  # Hooks
            self.context_object_name = self.title.lower()  # hooks

            self.context_object_name = self.context_object_name.replace(" ", "")
            self.context_object_name_singular = (
                self.context_object_name_singular.replace(" ", "")
            )
        super().__init__(*args, **kwargs)


class ObjectList(RestrictedViewMixin, ObjectNameMixin, ListView):
    allowed_types = ["modal", "widget", "window", "page"]
    window_content = "window-content/objects.html"
    list_template = None

    page_title = None
    page_subtitle = None

    list_url_name = None
    # WARNING: TAKEN FROM locals()
    list_url_args = ["type"]

    submit_url_name = None
    submit_url_args = ["type"]

    delete_all_url_name = None
    widget_options = None

    # copied from BaseListView
    def get(self, request, *args, **kwargs):
        type = kwargs.get("type", None)
        if not type:
            return HttpResponseBadRequest("No type specified")
        if type not in self.allowed_types:
            return HttpResponseBadRequest("Invalid type specified")

        self.request = request
        self.object_list = self.get_queryset(**kwargs)
        if isinstance(self.object_list, HttpResponse):
            return self.object_list
        if isinstance(self.object_list, HttpResponseBadRequest):
            return self.object_list
        allow_empty = self.get_allow_empty()

        self.template_name = f"wm/{type}.html"
        unique = str(uuid.uuid4())[:8]

        list_url_args = {}
        for arg in self.list_url_args:
            if arg in locals():
                list_url_args[arg] = locals()[arg]
            elif arg in kwargs:
                list_url_args[arg] = kwargs[arg]

        orig_type = type
        if type == "page":
            type = "modal"

        if not allow_empty:
            # When pagination is enabled and object_list is a queryset,
            # it's better to do a cheap query than to load the unpaginated
            # queryset in memory.
            if self.get_paginate_by(self.object_list) is not None and hasattr(
                self.object_list, "exists"
            ):
                is_empty = not self.object_list.exists()
            else:
                is_empty = not self.object_list
            if is_empty:
                raise Http404("Empty list")

        submit_url_args = {}
        for arg in self.submit_url_args:
            if arg in locals():
                submit_url_args[arg] = locals()[arg]
            elif arg in kwargs:
                submit_url_args[arg] = kwargs[arg]

        context = self.get_context_data()
        context["title"] = self.title + f" ({type})"
        context["title_singular"] = self.title_singular
        context["unique"] = unique
        context["window_content"] = self.window_content
        context["list_template"] = self.list_template
        context["page_title"] = self.page_title
        context["page_subtitle"] = self.page_subtitle
        context["type"] = type
        context["context_object_name"] = self.context_object_name
        context["context_object_name_singular"] = self.context_object_name_singular

        if self.submit_url_name is not None:
            context["submit_url"] = reverse(
                self.submit_url_name, kwargs=submit_url_args
            )

        if self.list_url_name is not None:
            context["list_url"] = reverse(self.list_url_name, kwargs=list_url_args)

        if self.delete_all_url_name:
            context["delete_all_url"] = reverse(self.delete_all_url_name)
        if self.widget_options:
            context["widget_options"] = self.widget_options

        # Return partials for HTMX
        if self.request.htmx:
            if request.headers["HX-Target"] == self.context_object_name + "-table":
                self.template_name = self.list_template
            elif orig_type == "page":
                self.template_name = self.list_template
            else:
                context["window_content"] = self.list_template
        return self.render_to_response(context)


class ObjectCreate(RestrictedViewMixin, ObjectNameMixin, CreateView):
    allowed_types = ["modal", "widget", "window", "page"]
    window_content = "window-content/object-form.html"
    parser_classes = [FormParser]

    page_title = None
    page_subtitle = None

    model = None
    submit_url_name = None
    submit_url_args = ["type"]

    request = None

    # Whether to hide the cancel button in the form
    hide_cancel = False

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.title = "Create " + self.context_object_name_singular

    def post_save(self, obj):
        pass

    def pre_save_mutate(self, user, obj):
        pass

    def form_valid(self, form):
        obj = form.save(commit=False)
        if self.request is None:
            raise Exception("Request is None")
        obj.user = self.request.user
        try:
            self.pre_save_mutate(self.request.user, obj)
        except AbortSave as e:
            context = {"message": f"Failed to save: {e}", "class": "danger"}
            return self.render_to_response(context)
        obj.save()
        form.save_m2m()
        self.post_save(obj)
        context = {"message": "Object created", "class": "success"}
        response = self.render_to_response(context)
        response["HX-Trigger"] = f"{self.context_object_name_singular}Event"
        return response

    def form_invalid(self, form):
        """If the form is invalid, render the invalid form."""
        return self.get(self.request, **self.kwargs, form=form)

    def get(self, request, *args, **kwargs):
        type = kwargs.get("type", None)
        if not type:
            return HttpResponseBadRequest("No type specified")
        if type not in self.allowed_types:
            return HttpResponseBadRequest("Invalid type specified")
        self.template_name = f"wm/{type}.html"
        unique = str(uuid.uuid4())[:8]

        self.request = request
        self.kwargs = kwargs

        if type == "widget":
            self.hide_cancel = True

        if type == "page":
            type = "modal"

        self.object = None

        submit_url_args = {}
        for arg in self.submit_url_args:
            if arg in locals():
                submit_url_args[arg] = locals()[arg]
            elif arg in kwargs:
                submit_url_args[arg] = kwargs[arg]
        submit_url = reverse(self.submit_url_name, kwargs=submit_url_args)

        context = self.get_context_data()
        form = kwargs.get("form", None)
        if form:
            context["form"] = form
        context["unique"] = unique
        context["window_content"] = self.window_content
        context["context_object_name"] = self.context_object_name
        context["context_object_name_singular"] = self.context_object_name_singular
        context["submit_url"] = submit_url
        context["type"] = type
        context["hide_cancel"] = self.hide_cancel
        if self.page_title:
            context["page_title"] = self.page_title
        if self.page_subtitle:
            context["page_subtitle"] = self.page_subtitle
        response = self.render_to_response(context)
        # response["HX-Trigger"] = f"{self.context_object_name_singular}Event"
        return response

    def post(self, request, *args, **kwargs):
        self.request = request
        self.template_name = "partials/notify.html"
        return super().post(request, *args, **kwargs)


class ObjectRead(RestrictedViewMixin, ObjectNameMixin, DetailView):
    allowed_types = ["modal", "widget", "window", "page"]
    window_content = "window-content/object.html"
    detail_template = "partials/generic-detail.html"

    page_title = None
    page_subtitle = None

    model = None
    # submit_url_name = None

    detail_url_name = None
    # WARNING: TAKEN FROM locals()
    detail_url_args = ["type"]

    request = None

    def get(self, request, *args, **kwargs):
        type = kwargs.get("type", None)
        if not type:
            return HttpResponseBadRequest("No type specified")
        if type not in self.allowed_types:
            return HttpResponseBadRequest()
        self.template_name = f"wm/{type}.html"
        unique = str(uuid.uuid4())[:8]

        detail_url_args = {}
        for arg in self.detail_url_args:
            if arg in locals():
                detail_url_args[arg] = locals()[arg]
            elif arg in kwargs:
                detail_url_args[arg] = kwargs[arg]

        self.request = request
        self.object = self.get_object(**kwargs)
        if isinstance(self.object, HttpResponse):
            return self.object

        orig_type = type
        if type == "page":
            type = "modal"

        context = self.get_context_data()

        context["title"] = self.title + f" ({type})"
        context["title_singular"] = self.title_singular
        context["unique"] = unique
        context["window_content"] = self.window_content
        context["detail_template"] = self.detail_template
        if self.page_title:
            context["page_title"] = self.page_title
        if self.page_subtitle:
            context["page_subtitle"] = self.page_subtitle
        context["type"] = type
        context["context_object_name"] = self.context_object_name
        context["context_object_name_singular"] = self.context_object_name_singular

        if self.detail_url_name is not None:
            context["detail_url"] = reverse(
                self.detail_url_name, kwargs=detail_url_args
            )

        # Return partials for HTMX
        if self.request.htmx:
            if request.headers["HX-Target"] == self.context_object_name + "-info":
                self.template_name = self.detail_template
            elif orig_type == "page":
                self.template_name = self.detail_template
            else:
                context["window_content"] = self.detail_template

        return self.render_to_response(context)


class ObjectUpdate(RestrictedViewMixin, ObjectNameMixin, UpdateView):
    allowed_types = ["modal", "widget", "window", "page"]
    window_content = "window-content/object-form.html"
    parser_classes = [FormParser]

    page_title = None
    page_subtitle = None

    model = None
    submit_url_name = None
    submit_url_args = ["type", "pk"]

    request = None

    # Whether pk is required in the get request
    pk_required = True

    # Whether to hide the cancel button in the form
    hide_cancel = False

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.title = "Update " + self.context_object_name_singular

    def post_save(self, obj):
        pass

    def form_valid(self, form):
        obj = form.save(commit=False)
        if self.request is None:
            raise Exception("Request is None")
        obj.save()
        form.save_m2m()
        self.post_save(obj)
        context = {"message": "Object updated", "class": "success"}
        response = self.render_to_response(context)
        response["HX-Trigger"] = f"{self.context_object_name_singular}Event"
        return response

    def form_invalid(self, form):
        """If the form is invalid, render the invalid form."""
        return self.get(self.request, **self.kwargs, form=form)

    def get(self, request, *args, **kwargs):
        self.request = request
        type = kwargs.get("type", None)
        pk = kwargs.get("pk", None)
        if not type:
            return HttpResponseBadRequest("No type specified")
        if not pk:
            if self.pk_required:
                return HttpResponseBadRequest("No pk specified")
        if type not in self.allowed_types:
            return HttpResponseBadRequest("Invalid type specified")
        self.template_name = f"wm/{type}.html"
        unique = str(uuid.uuid4())[:8]
        if type == "widget":
            self.hide_cancel = True

        if type == "page":
            type = "modal"

        self.object = self.get_object()

        submit_url_args = {}
        for arg in self.submit_url_args:
            if arg in locals():
                submit_url_args[arg] = locals()[arg]
            elif arg in kwargs:
                submit_url_args[arg] = kwargs[arg]
        submit_url = reverse(self.submit_url_name, kwargs=submit_url_args)

        context = self.get_context_data()
        form = kwargs.get("form", None)
        if form:
            context["form"] = form
        context["title"] = self.title + f" ({type})"
        context["title_singular"] = self.title_singular
        context["unique"] = unique
        context["window_content"] = self.window_content
        context["context_object_name"] = self.context_object_name
        context["context_object_name_singular"] = self.context_object_name_singular
        context["submit_url"] = submit_url
        context["type"] = type
        context["hide_cancel"] = self.hide_cancel
        if self.page_title:
            context["page_title"] = self.page_title
        if self.page_subtitle:
            context["page_subtitle"] = self.page_subtitle
        response = self.render_to_response(context)
        # response["HX-Trigger"] = f"{self.context_object_name_singular}Event"
        return response

    def post(self, request, *args, **kwargs):
        self.request = request
        self.template_name = "partials/notify.html"
        return super().post(request, *args, **kwargs)


class ObjectDelete(RestrictedViewMixin, ObjectNameMixin, DeleteView):
    model = None
    template_name = "partials/notify.html"

    # Overriden to prevent success URL from being used
    def delete(self, request, *args, **kwargs):
        """
        Call the delete() method on the fetched object and then redirect to the
        success URL.
        """
        self.object = self.get_object()
        # success_url = self.get_success_url()
        self.object.delete()
        context = {"message": "Object deleted", "class": "success"}
        response = self.render_to_response(context)
        response["HX-Trigger"] = f"{self.context_object_name_singular}Event"
        return response

    # This will be used in newer Django versions, until then we get a warning
    def form_valid(self, form):
        """
        Call the delete() method on the fetched object.
        """
        self.object = self.get_object()
        self.object.delete()
        context = {"message": "Object deleted", "class": "success"}
        response = self.render_to_response(context)
        response["HX-Trigger"] = f"{self.context_object_name_singular}Event"
        return response