from django.http import Http404
from django.shortcuts import get_object_or_404
from django.urls import reverse
from django.views.generic import DetailView, ListView, TemplateView

from .models import MainProduct, ProductVideo, SubProduct

VIDEO_PREVIEW_LIMIT = 3
VIDEO_ARCHIVE_PAGE_SIZE = 6


def _product_video_preview(queryset, archive_url):
    total = queryset.count()
    return {
        "product_videos": queryset[:VIDEO_PREVIEW_LIMIT],
        "videos_total_count": total,
        "videos_archive_url": archive_url if total > VIDEO_PREVIEW_LIMIT else "",
    }


class ProductOverviewView(ListView):
    model = MainProduct
    template_name = "products/overview.html"
    context_object_name = "main_products"
    queryset = MainProduct.objects.filter(is_active=True).prefetch_related(
        "sub_products", "people"
    )


class MainProductDetailView(DetailView):
    model = MainProduct
    template_name = "products/main_detail.html"
    context_object_name = "main_product"
    slug_url_kwarg = "main_slug"
    queryset = MainProduct.objects.filter(is_active=True).prefetch_related(
        "sub_products", "people"
    )

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context["articles"] = self.object.articles.prefetch_related(
            "sections", "citations", "people"
        ).all()
        videos = self.object.videos.filter(is_active=True).order_by("order", "pk")
        context.update(
            _product_video_preview(
                videos,
                reverse(
                    "products:main_product_videos",
                    kwargs={"main_slug": self.object.slug},
                ),
            )
        )
        return context


class SubProductDetailView(TemplateView):
    template_name = "products/sub_detail.html"

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        main_product = get_object_or_404(
            MainProduct,
            slug=self.kwargs["main_slug"],
            is_active=True,
        )
        sub_product = get_object_or_404(
            SubProduct.objects.prefetch_related("people"),
            slug=self.kwargs["sub_slug"],
            main_product=main_product,
            is_active=True,
        )
        context["main_product"] = main_product
        context["sub_product"] = sub_product
        context["articles"] = sub_product.articles.prefetch_related(
            "sections", "citations", "people"
        ).all()
        videos = sub_product.videos.filter(is_active=True).order_by("order", "pk")
        context.update(
            _product_video_preview(
                videos,
                reverse(
                    "products:sub_product_videos",
                    kwargs={
                        "main_slug": main_product.slug,
                        "sub_slug": sub_product.slug,
                    },
                ),
            )
        )
        context["siblings"] = (
            SubProduct.objects.filter(main_product=main_product, is_active=True)
            .exclude(pk=sub_product.pk)
            .order_by("order", "name")
        )
        return context


class ProductVideoArchiveView(ListView):
    model = ProductVideo
    template_name = "videos/archive.html"
    context_object_name = "videos"
    paginate_by = VIDEO_ARCHIVE_PAGE_SIZE

    def get_parent(self):
        main_product = get_object_or_404(
            MainProduct,
            slug=self.kwargs["main_slug"],
            is_active=True,
        )
        sub_slug = self.kwargs.get("sub_slug")
        if sub_slug:
            return get_object_or_404(
                SubProduct,
                slug=sub_slug,
                main_product=main_product,
                is_active=True,
            )
        return main_product

    def get_queryset(self):
        self.parent_object = self.get_parent()
        return self.parent_object.videos.filter(is_active=True).order_by("order", "pk")

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context.update(
            {
                "library_title": f"{self.parent_object.name} videos",
                "library_description": (
                    "Tutorials, demonstrations, and technical guides."
                ),
                "library_back_url": self.parent_object.get_absolute_url(),
                "library_back_label": f"Back to {self.parent_object.name}",
                "pagination_range": context["paginator"].get_elided_page_range(
                    context["page_obj"].number
                ),
            }
        )
        return context