urls.py

from django.conf import settings
from django.contrib import admin
from django.http import HttpRequest, HttpResponse, HttpResponseNotFound
from django.template.loader import render_to_string
from django.urls import include, path, re_path
from drf_spectacular.views import SpectacularAPIView, SpectacularSwaggerView
from meta.views import Meta  # type: ignore[import-untyped]

from api.llm_schema import LLM_SPECTACULAR_SETTINGS

_INDEX_HTML = settings.BASE_DIR / "web" / "dist" / "index.html"
_SHARE_IMAGE_SIZE = 600


class RequestMeta(Meta):
    """django-meta object that derives canonical host details from the request."""

    def get_domain(self):
        return self.request.get_host()

    def get_protocol(self):
        return self.request.scheme


def _index_html() -> str | None:
    if not _INDEX_HTML.exists():
        return None
    return _INDEX_HTML.read_text(encoding="utf-8")


def _spa(request: HttpRequest) -> HttpResponse | HttpResponseNotFound:
    index_html = _index_html()
    if index_html is not None:
        response = HttpResponse(index_html, content_type="text/html")
        response["Cache-Control"] = "no-cache, no-store, must-revalidate"
        return response
    return HttpResponseNotFound("Frontend not built.")


def _share_image_url(thumbnail: dict) -> str:
    """Prefer the eagerly cropped derivative; fall back to the raw asset URL."""
    return str(thumbnail.get("cropped_url") or thumbnail.get("url") or "")


def _inject_piece_metadata(index_html: str, request: HttpRequest, piece_id) -> str:
    from api.models import Piece
    from api.utils import image_to_dict
    from api.workflow import get_state_friendly_name

    piece = (
        Piece.objects.select_related("thumbnail")
        .prefetch_related("states", "states__image_links")
        .filter(id=piece_id, shared=True)
        .first()
    )
    if piece is None or piece.current_state is None:
        return index_html

    state_label = get_state_friendly_name(piece.current_state.state)
    title = f"{piece.name} - {state_label}"
    description = "Powered by PotterDoc"
    url = request.build_absolute_uri(request.path)
    thumbnail = image_to_dict(piece.thumbnail)
    if thumbnail:
        thumbnail["cropped_url"] = piece.get_thumbnail_cropped_url()
    image_url = _share_image_url(thumbnail) if thumbnail else ""
    if image_url.startswith("/"):
        image_url = request.build_absolute_uri(image_url)

    meta = RequestMeta(
        request=request,
        title=title,
        description=description,
        url=url,
        image=image_url,
        image_width=_SHARE_IMAGE_SIZE if image_url else None,
        image_height=_SHARE_IMAGE_SIZE if image_url else None,
        object_type="article",
        site_name="PotterDoc",
        twitter_type="summary_large_image",
        use_og=True,
        use_twitter=True,
        use_title_tag=True,
    )
    tags = render_to_string("meta/meta.html", {"meta": meta}).strip()
    index_html = index_html.replace("<title>PotterDoc</title>", tags, 1)
    return index_html


def _piece_spa(request: HttpRequest, piece_id) -> HttpResponse | HttpResponseNotFound:
    index_html = _index_html()
    if index_html is None:
        return HttpResponseNotFound("Frontend not built.")
    response = HttpResponse(
        _inject_piece_metadata(index_html, request, piece_id),
        content_type="text/html",
    )
    response["Cache-Control"] = "no-cache, no-store, must-revalidate"
    return response


urlpatterns = [
    path(f"{settings.ADMIN_URL}/", admin.site.urls),
    path("api/", include("api.urls")),
    path("support/", include("helpdesk.urls")),
    path("api/schema/", SpectacularAPIView.as_view(), name="schema"),
    path(
        "api/schema/llm/",
        SpectacularAPIView.as_view(custom_settings=LLM_SPECTACULAR_SETTINGS),
        name="schema-llm",
    ),
    path(
        "api/schema/swagger/",
        SpectacularSwaggerView.as_view(url_name="schema"),
        name="swagger",
    ),
    path("pieces/<uuid:piece_id>", _piece_spa),
    path("pieces/<uuid:piece_id>/showcase", _piece_spa),
    # Catch-all: serve the React SPA for client routes only. File-like URLs
    # (for example Vite chunk files) must fall through so static handling can
    # return the real asset or a 404 instead of HTML.
    re_path(rf"^(?!api/|{settings.ADMIN_URL}|static/|.*\..*$).*$", _spa),
]