import logging

import httpx
from django.core.handlers.wsgi import WSGIRequest
from django.http import HttpResponse
from django.shortcuts import render
from django.utils import timezone
from django.views import View

from pydis_site import settings
from pydis_site.apps.home.models import RepositoryMetadata

log = logging.getLogger(__name__)


class HomeView(View):
    """The main landing page for the website."""

    github_api = "https://api.github.com/users/python-discord/repos?per_page=100"
    repository_cache_ttl = 3600

    # Which of our GitHub repos should be displayed on the front page, and in which order?
    repos = [
        "python-discord/site",
        "python-discord/bot",
        "python-discord/snekbox",
        "python-discord/sir-lancebot",
        "python-discord/metricity",
        "python-discord/king-arthur",
    ]

    def __init__(self):
        """Clean up stale RepositoryMetadata."""
        if not settings.STATIC_BUILD:
            RepositoryMetadata.objects.exclude(repo_name__in=self.repos).delete()

        # If no token is defined (for example in local development), then
        # it does not make sense to pass the Authorization header. More
        # specifically, GitHub will reject any requests from us due to the
        # invalid header. We can make a limited number of anonymous requests
        # though, which is useful for testing.
        if settings.GITHUB_TOKEN:
            self.headers = {"Authorization": f"token {settings.GITHUB_TOKEN}"}
        else:
            self.headers = {}

    def _get_api_data(self) -> dict[str, dict[str, str]]:
        """
        Call the GitHub API and get information about our repos.

        If we're unable to get that info for any reason, return an empty dict.
        """
        repo_dict = {}
        try:
            # Fetch the data from the GitHub API
            api_data: list[dict] = httpx.get(
                self.github_api,
                headers=self.headers,
                timeout=settings.TIMEOUT_PERIOD
            ).json()
        except httpx.TimeoutException:
            log.error("Request to fetch GitHub repository metadata for timed out!")
            return repo_dict

        # Process the API data into our dict
        for repo in api_data:
            try:
                full_name = repo["full_name"]

                if full_name in self.repos:
                    repo_dict[full_name] = {
                        "full_name": repo["full_name"],
                        "description": repo["description"],
                        "language": repo["language"],
                        "forks_count": repo["forks_count"],
                        "stargazers_count": repo["stargazers_count"],
                    }
            # Something is not right about the API data we got back from GitHub.
            except (TypeError, ConnectionError, KeyError) as e:
                log.error(
                    "Unable to parse the GitHub repository metadata from response!",
                    extra={
                        'api_data': api_data,
                        'error': e
                    }
                )
                continue

        return repo_dict

    def _get_repo_data(self) -> list[RepositoryMetadata]:
        """Build a list of RepositoryMetadata objects that we can use to populate the front page."""
        # First off, load the timestamp of the least recently updated entry.
        if settings.STATIC_BUILD:
            last_update = None
        else:
            last_update = (
                RepositoryMetadata.objects.values_list("last_updated", flat=True)
                .order_by("last_updated").first()
            )

        # If we did not retrieve any results here, we should import them!
        if last_update is None:

            # Try to get new data from the API. If it fails, we'll return an empty list.
            # In this case, we simply don't display our projects on the site.
            api_repositories = self._get_api_data()

            # Create all the repodata records in the database.
            data = [
                RepositoryMetadata(
                    repo_name=api_data["full_name"],
                    description=api_data["description"],
                    forks=api_data["forks_count"],
                    stargazers=api_data["stargazers_count"],
                    language=api_data["language"],
                )
                for api_data in api_repositories.values()
            ]

            if settings.STATIC_BUILD:
                return data
            return RepositoryMetadata.objects.bulk_create(data)

        # If the data is stale, we should refresh it.
        if (timezone.now() - last_update).seconds > self.repository_cache_ttl:
            # Try to get new data from the API. If it fails, return the cached data.
            api_repositories = self._get_api_data()

            if not api_repositories:
                return RepositoryMetadata.objects.all()

            # Update or create all RepoData objects in self.repos
            database_repositories = []
            for api_data in api_repositories.values():
                repo_data, _created = RepositoryMetadata.objects.update_or_create(
                    repo_name=api_data["full_name"],
                    defaults={
                        'repo_name': api_data["full_name"],
                        'description': api_data["description"],
                        'forks': api_data["forks_count"],
                        'stargazers': api_data["stargazers_count"],
                        'language': api_data["language"],
                    }
                )
                database_repositories.append(repo_data)
            return database_repositories

        # Otherwise, if the data is fresher than 2 minutes old, we should just return it.
        return RepositoryMetadata.objects.all()

    def get(self, request: WSGIRequest) -> HttpResponse:
        """Collect repo data and render the homepage view."""
        repo_data = self._get_repo_data()
        return render(request, "home/index.html", {"repo_data": repo_data})


def timeline(request: WSGIRequest) -> HttpResponse:
    """Render timeline view."""
    return render(request, 'home/timeline.html')