"""XYZ tile map interface (served by mapserve, in both images).

The HTML, CSS and JS live in `web/` (real files, read at import time);
`write_map_assets()` bakes them into the image at build time. The page is a
minimal shell: all state comes from `/api/map/meta`, the layers are standard
`L.tileLayer`s — the browser handles LOD, caching and animation.
"""

import hashlib
from pathlib import Path

ASSETS_DIRNAME = "mapserve_assets"

WEB_DIR = Path(__file__).resolve().parent / "web"


def _read_web(name):
    """Interface file (HTML/CSS/JS), read once at import time."""
    return (WEB_DIR / name).read_text(encoding="utf-8")


_MAP_HTML = _read_web("map.html")
_MAP_CSS = _read_web("map.css")
_MAP_JS = _read_web("map.js")


def ui_version():
    """Short hash of CSS+JS: used as the version in asset URLs."""
    return hashlib.sha1((_MAP_CSS + _MAP_JS).encode("utf-8")).hexdigest()[:10]


def write_map_assets(assets_dir):
    """Writes app.css / app.js (+ vendored Leaflet) into `assets_dir`."""
    import shutil
    assets_dir = Path(assets_dir)
    assets_dir.mkdir(parents=True, exist_ok=True)
    (assets_dir / "app.css").write_text(_MAP_CSS, encoding="utf-8")
    (assets_dir / "app.js").write_text(
        _MAP_JS.replace("__UI_VERSION__", ui_version()), encoding="utf-8")
    src_vendor = Path(__file__).parent / "assets" / "vendor"
    dst_vendor = assets_dir / "vendor"
    if src_vendor.is_dir():
        shutil.rmtree(dst_vendor, ignore_errors=True)
        shutil.copytree(src_vendor, dst_vendor)
    return assets_dir


def render_html():
    """HTML shell (data loaded from /api/map/meta)."""
    return _MAP_HTML.replace("__ASSETS_V__", ui_version())