import { useState } from 'react';
import { Monitor, QrCode, Store, UserCog, UserRound, Users } from 'lucide-react';
import { StoreQrDrawer } from './StoreQrDrawer';
import { AppShell, IconButton, type MenuEntry, type NavEntry } from '@/components/shell/AppShell';
import { useAuth } from '@/auth/AuthContext';
import { useTenantLocations } from '@/queries/hooks';
import { BranchScopeProvider, useBranchScope } from '@/features/store-admin/BranchScope';

/**
 * Store user — one branch, and only that branch.
 *
 * The same four destinations as the Store Admin, for the same reason: the
 * questions a shop asks in a day are what did we take, what do we sell, what is
 * on the shelf, and how did the period go. What changes is the scope, not the
 * shape — so the pages are the merchant's pages with the branch fixed, rather
 * than a second set that drifts.
 *
 * The old console gave this role five nav entries over a six-tab hub, and one
 * of them (Store Console) rendered another one (Products) inside itself. Four
 * pages, each owning one question, replaces it.
 */
const NAV: readonly NavEntry[] = [
  { to: '/store/console', label: 'Console' },
  { to: '/store/products', label: 'Products' },
  { to: '/store/sales', label: 'Sales' },
  { to: '/store/reports', label: 'Reports' },
];

/**
 * The account menu.
 *
 * Everything here is either about this person, or about the shop's fittings —
 * reached when something needs checking, not worked from hour to hour. The
 * merchant's "New branch" entry is deliberately absent: a shop does not
 * commission outlets, and `createtenantlocation` also spawns a login.
 *
 * Customers sits here rather than in the nav because the four nav slots each
 * answer a question about the trading day, and "who orders from us" is a
 * lookup. Move it up if the shop uses it hourly.
 *
 * The store QR is NOT here — it is an icon in the header, because it opens in
 * place and closes again. A destination is for somewhere you work; this is
 * something you glance at and print.
 */
const MANAGE: readonly MenuEntry[] = [
  {
    to: '/store/customers',
    label: 'Customers',
    icon: <Users size={13} />,
    note: 'Who orders from this shop',
  },
  {
    to: '/store/terminals',
    label: 'Terminals',
    icon: <Monitor size={13} />,
    note: 'Till health at this counter',
  },
  {
    to: '/store/staff',
    label: 'Counter staff',
    icon: <UserCog size={13} />,
    note: 'Who can open the till',
  },
  {
    to: '/store/account',
    label: 'My account',
    icon: <UserRound size={13} />,
    note: 'Profile and store binding',
  },
];

/**
 * Resolve the outlet this account is bound to.
 *
 * Two steps, and no third. `app_users.locationid` is the binding; a tenant with
 * exactly one outlet needs no id at all. The old console had four more
 * fallbacks below these — including matching the email's local part against a
 * store's address, and falling back to `applocationid` — and those are guesses
 * at an authorisation boundary. `applocationid` is a CITY id: passing one to a
 * POS read returns an empty board, or another shop's takings if the numbers
 * happen to collide.
 */
function useResolvedOutlet(): { locationid: number | null; isLoading: boolean } {
  const { user } = useAuth();
  const { data, isLoading } = useTenantLocations(user?.tenantid || undefined);
  const branches = data ?? [];

  if (user?.locationid && user.locationid > 0) return { locationid: user.locationid, isLoading };
  if (isLoading) return { locationid: null, isLoading: true };
  if (branches.length === 1 && branches[0]) return { locationid: branches[0].locationid, isLoading };
  return { locationid: null, isLoading: false };
}

export function StoreUserShell() {
  const { locationid, isLoading } = useResolvedOutlet();
  const [isQrOpen, setQrOpen] = useState(false);

  if (isLoading) return <Resolving />;
  if (locationid === null) return <NoStore />;

  return (
    <BranchScopeProvider pin={locationid}>
      <AppShell
        nav={NAV}
        home="/store/console"
        navLabel="Store"
        scopeControl={<BranchPill />}
        manageItems={MANAGE}
        headerActions={
          <IconButton label="Store QR code" onClick={() => setQrOpen(true)}>
            <QrCode size={16} />
          </IconButton>
        }
      />
      {isQrOpen ? <StoreQrDrawer onClose={() => setQrOpen(false)} /> : null}
    </BranchScopeProvider>
  );
}

/**
 * Where the merchant has a branch selector, the shop has a label.
 *
 * Same slot, same size, same position — so the two workspaces read as one
 * product — but not a control, because there is nothing to choose. A disabled
 * dropdown would say "you may not switch"; a label says "this is your shop",
 * which is the true statement.
 */
function BranchPill() {
  const { current, isLoading } = useBranchScope();
  const label = isLoading ? 'Loading…' : (current?.locationname ?? 'Your store');

  return (
    <span
      style={{
        display: 'inline-flex',
        alignItems: 'center',
        gap: 7,
        height: 32,
        maxWidth: 230,
        padding: '0 12px',
        borderRadius: 12,
        border: '1px solid var(--color-line)',
        background: 'var(--color-surface-subtle)',
        color: 'var(--color-ink-1)',
        fontSize: 13,
        fontWeight: 500,
      }}
    >
      <Store size={14} style={{ color: 'var(--color-brand)', flex: 'none' }} />
      <span
        style={{ minWidth: 0, overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}
      >
        {label}
      </span>
    </span>
  );
}

function Resolving() {
  return (
    <div style={{ minHeight: '100vh', display: 'grid', placeItems: 'center', padding: 24 }}>
      <p style={{ color: 'var(--color-slate-500)', fontSize: 14 }}>Finding your store…</p>
    </div>
  );
}

/**
 * The honest refusal.
 *
 * Every read on every page below is authorised by `locationid` alone, so a page
 * that guessed one would not fail loudly — it would quietly show another shop's
 * takings, or an empty board that reads as a quiet day.
 */
function NoStore() {
  const { signOut } = useAuth();
  return (
    <div style={{ minHeight: '100vh', display: 'grid', placeItems: 'center', padding: 24 }}>
      <div style={{ maxWidth: 440, textAlign: 'center' }}>
        <h1 style={{ fontFamily: 'var(--font-display)', fontSize: 22, marginBottom: 8 }}>
          No store assigned
        </h1>
        <p style={{ color: 'var(--color-slate-500)', fontSize: 14, lineHeight: 1.65 }}>
          Your account is not linked to a branch yet, so there is nothing to show. Ask your store
          administrator to allocate you to one.
        </p>
        <button
          type="button"
          onClick={signOut}
          style={{
            marginTop: 20,
            height: 32,
            padding: '0 14px',
            borderRadius: 12,
            border: '1px solid var(--color-line)',
            background: 'var(--color-surface)',
            fontSize: 13,
            cursor: 'pointer',
          }}
        >
          Sign out
        </button>
      </div>
    </div>
  );
}