"""WebUI Vite asset helpers."""

from __future__ import annotations

import json
import os
from pathlib import Path
from typing import Any, Callable

from utils.logging_config import get_logger as _create_logger

logger = _create_logger("webui.assets")

DEFAULT_WEBUI_VITE_ENTRY = "src/app/main.tsx"
DEFAULT_WEBUI_VITE_BASE = "/static/dist/"
DEFAULT_WEBUI_VITE_DEV_URL = "http://127.0.0.1:5173"
DEFAULT_WEBUI_VITE_DEV_ENV = "SOULSYNC_WEBUI_VITE_DEV"
DEFAULT_WEBUI_VITE_URL_ENV = "SOULSYNC_WEBUI_VITE_URL"

_MANIFEST_CACHE: dict[str, tuple[float | None, dict[str, Any]]] = {}


def get_webui_vite_manifest_path() -> Path:
    """Return the generated Vite manifest path inside the repo."""
    return Path(__file__).resolve().parents[2] / "webui" / "static" / "dist" / ".vite" / "manifest.json"


def clear_webui_vite_manifest_cache() -> None:
    """Clear the in-process manifest cache. Primarily useful for tests."""
    _MANIFEST_CACHE.clear()


def default_static_url_builder(filename: str) -> str:
    """Build a Flask-style static URL without requiring Flask imports."""
    return f"/static/{filename.lstrip('/')}"


def _env_truthy(value: str | None) -> bool:
    return (value or "").lower() in {"1", "true", "yes", "on"}


def _resolve_dev_mode(dev: bool | None) -> bool:
    if dev is not None:
        return bool(dev)
    return _env_truthy(os.environ.get(DEFAULT_WEBUI_VITE_DEV_ENV))


def _resolve_dev_url(dev_url: str | None) -> str:
    if dev_url:
        return dev_url.rstrip("/")
    return os.environ.get(DEFAULT_WEBUI_VITE_URL_ENV, DEFAULT_WEBUI_VITE_DEV_URL).rstrip("/")


def load_webui_vite_manifest(manifest_path: str | Path | None = None) -> dict[str, Any]:
    """Load and cache the generated Vite manifest."""
    path = Path(manifest_path) if manifest_path else get_webui_vite_manifest_path()
    cache_key = str(path)
    manifest_mtime = None
    if path.exists():
        try:
            manifest_mtime = path.stat().st_mtime
        except OSError:
            manifest_mtime = None

    cached = _MANIFEST_CACHE.get(cache_key)
    if cached and cached[0] == manifest_mtime:
        return cached[1]

    if path.exists():
        try:
            with path.open("r", encoding="utf-8") as handle:
                manifest = json.load(handle)
        except Exception as exc:
            logger.warning("Failed to load webui manifest: %s", exc)
            manifest = {}
    else:
        manifest = {}

    _MANIFEST_CACHE[cache_key] = (manifest_mtime, manifest)
    return manifest


def build_webui_vite_assets(
    placement: str = "body",
    *,
    dev: bool | None = None,
    dev_url: str | None = None,
    entry: str = DEFAULT_WEBUI_VITE_ENTRY,
    manifest_path: str | Path | None = None,
    manifest_loader: Callable[[], dict[str, Any]] | None = None,
    static_url_builder: Callable[[str], str] | None = None,
) -> str:
    """Return HTML tags for the WebUI bundle or dev client."""
    if placement not in ("head", "body"):
        return ""

    dev_mode = _resolve_dev_mode(dev)
    vite_url = _resolve_dev_url(dev_url)
    static_url = static_url_builder or default_static_url_builder

    if dev_mode:
        if placement == "head":
            return ""
        base = DEFAULT_WEBUI_VITE_BASE.rstrip("/")
        return "\n".join([
            f'<script type="module" src="{vite_url}{base}/@vite/client"></script>',
            f'<script type="module" src="{vite_url}{base}/{entry.lstrip("/")}"></script>',
        ])

    loader = manifest_loader or (lambda: load_webui_vite_manifest(manifest_path))
    manifest = loader()
    entry_meta = manifest.get(entry)
    if not entry_meta:
        return ""

    if placement == "head":
        return "\n".join(
            f'<link rel="stylesheet" href="{static_url(f"dist/{css_file}")}">'
            for css_file in entry_meta.get("css", [])
        )

    entry_file = entry_meta.get("file")
    if not entry_file:
        return ""

    return f'<script type="module" src="{static_url(f"dist/{entry_file}")}"></script>'