from typing import Dict, List

import requests
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.apps.home.models import RepositoryMetadata


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

    github_api = "https://api.github.com/users/python-discord/repos"
    repository_cache_ttl = 600

    # 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/seasonalbot",
        "python-discord/django-simple-bulma",
        "python-discord/django-crispy-bulma",
    ]

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

        repo_dict = {repo_name: {} for repo_name in self.repos}

        # Fetch the data from the GitHub API
        api_data = requests.get(self.github_api)
        api_data = api_data.json()

        # Process the API data into our dict
        for repo in api_data:
            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"],
                }
        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."""

        # Try to get site data from the cache
        try:
            repo_data = RepositoryMetadata.objects.get(repo_name="python-discord/site")

            # If the data is stale, we should refresh it.
            if (timezone.now() - repo_data.last_updated).seconds > self.repository_cache_ttl:

                # Get new data from API
                api_repositories = self._get_api_data()
                database_repositories = []

                # Update or create all RepoData objects in self.repos
                for repo_name, api_data in api_repositories.items():
                    try:
                        repo_data = RepositoryMetadata.objects.get(repo_name=repo_name)
                        repo_data.description = api_data["description"]
                        repo_data.language = api_data["language"]
                        repo_data.forks = api_data["forks_count"]
                        repo_data.stargazers = api_data["stargazers_count"]
                    except RepositoryMetadata.DoesNotExist:
                        repo_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"],
                        )
                    repo_data.save()
                    database_repositories.append(repo_data)
                return database_repositories

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

        # If this is raised, the database has no repodata at all, we will create them all.
        except RepositoryMetadata.DoesNotExist:

            # Get new data from API
            api_repositories = self._get_api_data()
            database_repositories = []

            # Create all the repodata records in the database.
            for api_data in api_repositories.values():
                repo_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"],
                )
                repo_data.save()
                database_repositories.append(repo_data)

            return database_repositories

    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})