from django.db.models import Prefetch, Q
from django.shortcuts import get_object_or_404
from django.urls import path
from ninja import NinjaAPI, Router

from blog import api as reference
from blog.models import Post, Tag
from blog.schemas import (
    CommentCreateOut,
    PostCreateOut,
    PostDetailOut,
    PostListOut,
    UserDetailOut,
)

router = Router()


def eager(query):
    return (
        query.select_related("author")
        .only(
            "id", "title", "view_count", "created_at",
            "author__id", "author__username", "author__display_name",
        )
        .prefetch_related(Prefetch("tags", queryset=Tag.objects.only("id", "name", "slug")))
    )


@router.get("/posts", response=list[PostListOut])
def list_posts(request):
    posts = eager(Post.objects.filter(is_published=True).order_by("-created_at"))
    return [reference._serialize_post_list(p) for p in posts]


@router.get("/posts/search", response=list[PostListOut])
def search_posts(request, q: str):
    posts = eager(Post.objects.filter(
        Q(title__icontains=q) | Q(body__icontains=q), is_published=True,
    ).order_by("-created_at"))
    return [reference._serialize_post_list(p) for p in posts]


@router.get("/posts/by-tag/{slug}", response=list[PostListOut])
def posts_by_tag(request, slug: str):
    tag = get_object_or_404(Tag, slug=slug)
    posts = eager(tag.posts.filter(is_published=True).order_by("-created_at"))
    return [reference._serialize_post_list(p) for p in posts]


# Reuse original handlers for unchanged endpoints and their exact failure paths.
router.get("/posts/{post_id}", response=PostDetailOut)(reference.get_post)
router.post("/posts", response=PostCreateOut)(reference.create_post)
router.post("/posts/{post_id}/comments", response=CommentCreateOut)(reference.create_comment)
router.get("/users/find", response=UserDetailOut)(reference.find_user_by_email)
router.get("/users/{user_id}", response=UserDetailOut)(reference.get_user)

api = NinjaAPI()
api.add_router("/", router)
urlpatterns = [path("api/", api.urls)]