"""The left menu, declared once. An entry is shown only to users who may open its page."""

from __future__ import annotations

from dataclasses import dataclass

from django.urls import reverse
from django.utils.translation import gettext_lazy as _


@dataclass(frozen=True)
class Entry:
    label: object  # lazy translated string
    url_name: str


@dataclass(frozen=True)
class Group:
    title: object | None
    role: str | None  # None: everyone; otherwise "publisher" or "admin"
    entries: tuple[Entry, ...]


MENU = (
    Group(None, None, (Entry(_("Home"), "home"),)),
    Group(
        _("Publishing"),
        "publisher",
        (Entry(_("Manage announcements"), "publish-announcements"),),
    ),
    Group(
        _("Administration"),
        "admin",
        (
            Entry(_("Appearance"), "admin-appearance"),
            Entry(_("Settings"), "admin-settings"),
            Entry(_("Audit log"), "admin-audit"),
            Entry(_("Status"), "admin-status"),
        ),
    ),
)


def _allowed(group: Group, portal_user) -> bool:
    if group.role is None:
        return True
    return bool(getattr(portal_user, f"is_{group.role}", False))


def for_user(portal_user, current_path: str) -> list[dict]:
    """The groups this user sees, each entry with its address and whether it is current."""
    groups = []
    for group in MENU:
        if not _allowed(group, portal_user):
            continue
        entries = []
        for entry in group.entries:
            url = reverse(entry.url_name)
            entries.append({"label": entry.label, "url": url, "current": url == current_path})
        groups.append({"title": group.title, "entries": entries})
    return groups