"""Shared web UI resources for EPUB search."""

from __future__ import annotations

from pathlib import Path
from typing import TYPE_CHECKING

from fastapi.templating import Jinja2Templates

if TYPE_CHECKING:
    from fastapi import Request
    from fastapi.responses import HTMLResponse

PACKAGE_DIR = Path(__file__).resolve().parent
TEMPLATE_DIR = PACKAGE_DIR / "templates"
STATIC_DIR = PACKAGE_DIR / "static"


def static_version(filename: str) -> int:
    """Return a cache-busting token for a static file based on its modification time."""
    try:
        return int((STATIC_DIR / filename).stat().st_mtime)
    except OSError:
        return 0


templates = Jinja2Templates(directory=TEMPLATE_DIR)
templates.env.globals["static_version"] = static_version


def error_response(request: Request, message: object) -> HTMLResponse:
    """Render the shared error partial for a failed UI request."""
    return templates.TemplateResponse(request, "partials/error.html", {"message": str(message)}, status_code=500)