import structlog

from django.http import Http404
from django.shortcuts import get_object_or_404, redirect
from django.views.generic import DetailView, ListView
from django.views.generic.edit import FormMixin

from versions.models import Version
from .forms import VersionSelectionForm
from .github import GithubAPIClient
from .models import Category, Issue, Library, LibraryVersion, PullRequest

logger = structlog.get_logger()


class CategoryMixin:
    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context["categories"] = Category.objects.all().order_by("name")
        return context


class LibraryList(CategoryMixin, ListView):
    """List all of our libraries for a specific Boost version, or default
    to the current version."""

    queryset = (
        Library.objects.prefetch_related("authors", "categories").all().order_by("name")
    ).distinct()
    template_name = "libraries/list.html"

    def get_queryset(self):
        queryset = super().get_queryset()
        params = self.request.GET.copy()

        # default to the most recent version
        if "version" not in params:
            params["version"] = Version.objects.most_recent().slug

        queryset = queryset.filter(library_version__version__slug=params["version"])

        # avoid attempting to look up libraries with blank categories
        if "category" in params and params["category"] != "":
            queryset = queryset.filter(categories__slug=params["category"])

        return queryset

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        if "category" in self.request.GET and self.request.GET["category"] != "":
            context["category"] = Category.objects.get(
                slug=self.request.GET["category"]
            )
        if "version" in self.request.GET:
            context["version"] = Version.objects.get(slug=self.request.GET["version"])
        else:
            context["version"] = Version.objects.most_recent()
        context["versions"] = Version.objects.active().order_by("-release_date")
        context["library_list"] = self.get_queryset()
        return context


class LibraryListMini(LibraryList):
    """Flat list version of LibraryList"""

    template_name = "libraries/flat_list.html"


class LibraryListByCategory(LibraryList):
    """List all Boost libraries sorted by Category."""

    template_name = "libraries/category_list.html"

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context["by_category"] = True
        context["library_list"] = self.get_results_by_category()
        return context

    def get_results_by_category(self):
        queryset = super().get_queryset()
        results_by_category = []
        for category in Category.objects.all().order_by("name"):
            results_by_category.append(
                {
                    "category": category,
                    "libraries": queryset.filter(categories=category).order_by("name"),
                }
            )
        return results_by_category


class LibraryListByCategoryMini(LibraryListByCategory):
    """Flat list version of LibraryListByCategory"""

    template_name = "libraries/list.html"


class LibraryDetail(CategoryMixin, FormMixin, DetailView):
    """Display a single Library in insolation"""

    form_class = VersionSelectionForm
    model = Library
    template_name = "libraries/detail.html"

    def get_context_data(self, **kwargs):
        """Set the form action to the main libraries page"""
        context = super().get_context_data(**kwargs)
        context["closed_prs_count"] = self.get_closed_prs_count(self.object)
        context["open_issues_count"] = self.get_open_issues_count(self.object)
        context["version"] = self.get_version()
        context["maintainers"] = self.get_maintainers(context["version"])
        context["versions"] = (
            Version.objects.active()
            .filter(library_version__library=self.object)
            .distinct()
            .order_by("-release_date")
        )
        client = GithubAPIClient(repo_slug=self.object.github_repo)
        context["description"] = self.object.get_description(
            client, tag=context["version"].name
        )
        return context

    def get_object(self):
        """Get the current library object from the slug in the URL.
        If present, use the version_slug to get the right LibraryVersion of the library.
        Otherwise, default to the most recent version."""
        slug = self.kwargs.get("slug")
        version = self.get_version()

        if not LibraryVersion.objects.filter(
            version=version, library__slug=slug
        ).exists():
            raise Http404("No library found matching the query")

        try:
            obj = self.get_queryset().get(slug=slug)
        except self.model.DoesNotExist:
            raise Http404("No library found matching the query")
        return obj

    def get_closed_prs_count(self, obj):
        """Get the number of closed pull requests for the current library."""
        return PullRequest.objects.filter(library=obj, is_open=True).count()

    def get_maintainers(self, version):
        """Get the maintainers for the current LibraryVersion."""
        obj = self.get_object()
        library_version = LibraryVersion.objects.get(library=obj, version=version)
        return library_version.maintainers.all()

    def get_open_issues_count(self, obj):
        """Get the number of open issues for the current library."""
        return Issue.objects.filter(library=obj, is_open=True).count()

    def get_version(self):
        """Get the version of Boost for the library we're currently looking at."""
        version_slug = self.kwargs.get("version_slug")
        if version_slug:
            return get_object_or_404(Version, slug=version_slug)
        else:
            return Version.objects.most_recent()

    def post(self, request, *args, **kwargs):
        """User has submitted a form and will be redirected to the right record."""
        self.object = self.get_object()
        form = self.get_form()
        if form.is_valid():
            version = form.cleaned_data["version"]
            return redirect(
                "library-detail-by-version",
                version_slug=version.slug,
                slug=self.object.slug,
            )
        else:
            logger.info("library_list_invalid_version")
        return super().get(request)