import { useRef, useState, useEffect } from "react";
import { Check, LogOut, Settings, UserCircle } from "lucide-react";
import type { ApiSettings, AuthInfo, AuthTenantMembership, LoginResponse } from "../types";
import HelpMenu from "./HelpMenu";
import LanguageMenu from "./LanguageMenu";
import LoginModal from "../features/auth/LoginModal";
import DismissibleAlert from "../components/DismissibleAlert";
import { useGuardedNavigate, useUnsavedChanges } from "../components/UnsavedChangesGuard";
import { logout, switchTenant } from "../api/auth";
import { hasAnyScope } from "../utils/permissions";
import { usePlatformLanguage } from "../i18n/LanguageContext";

type Props = {
  settings: ApiSettings;
  auth: AuthInfo | null;
  onSettingsChange: (settings: ApiSettings) => void;
  onAuthChange: (auth: AuthInfo | null, accessToken?: string) => void;
  maintenanceMode?: {enabled: boolean;message?: string | null;};
};

export default function Titlebar({ settings, auth, onAuthChange, maintenanceMode }: Props) {
  const navigate = useGuardedNavigate();
  const { requestNavigation } = useUnsavedChanges();
  const [accountOpen, setAccountOpen] = useState(false);
  const [tenantOpen, setTenantOpen] = useState(false);
  const [loginOpen, setLoginOpen] = useState(false);
  const [switchingTenantId, setSwitchingTenantId] = useState<string | null>(null);
  const [tenantError, setTenantError] = useState("");
  const accountRef = useRef<HTMLDivElement>(null);
  const tenantRef = useRef<HTMLDivElement>(null);
  const { translateText } = usePlatformLanguage();

  const activeTenant = auth?.active_tenant ?? auth?.tenant ?? null;
  const tenants = auth?.tenants ?? (activeTenant ? [activeTenant] : []);
  const displayUserName = auth?.user?.display_name || auth?.user?.email || translateText("i18n:govoplan-core.sign_in.ada2e9e9");
  const canSwitchTenant = tenants.length > 1;
  const canAdministerTenants = hasAnyScope(auth, [
  "system:tenants:read",
  "system:tenants:create",
  "system:tenants:update",
  "system:tenants:suspend"]
  );
  const showTenantControl = Boolean(activeTenant && (canSwitchTenant || canAdministerTenants));

  useEffect(() => {
    function onPointerDown(event: MouseEvent) {
      const target = event.target as Node;
      if (accountRef.current && !accountRef.current.contains(target)) {
        setAccountOpen(false);
      }
      if (tenantRef.current && !tenantRef.current.contains(target)) {
        setTenantOpen(false);
      }
    }
    window.addEventListener("mousedown", onPointerDown);
    return () => window.removeEventListener("mousedown", onPointerDown);
  }, []);

  function handleLogin(response: LoginResponse) {
    onAuthChange(response, "");
  }

  async function performLogout() {
    try {
      await logout(settings);
    } catch {

      // Logout is best effort; clear local session either way.
    }
    onAuthChange(null, "");
    setAccountOpen(false);
  }

  async function performTenantSelect(tenant: AuthTenantMembership) {
    setSwitchingTenantId(tenant.id);
    setTenantError("");
    try {
      const next = await switchTenant(settings, tenant.id);
      // Keep the current URL. The tenant-keyed route tree reloads in the new
      // context; permission and resource boundaries then retain the page or
      // fall back to the nearest accessible parent.
      onAuthChange(next);
      setTenantOpen(false);
    } catch (error) {
      setTenantError(error instanceof Error ? error.message : translateText("i18n:govoplan-core.tenant_switch_failed.c325b20b"));
    } finally {
      setSwitchingTenantId(null);
    }
  }

  function handleLogout() {
    requestNavigation(() => {void performLogout();});
  }

  function handleTenantSelect(tenant: AuthTenantMembership) {
    if (!auth || tenant.id === activeTenant?.id || switchingTenantId) {
      setTenantOpen(false);
      return;
    }
    requestNavigation(() => {void performTenantSelect(tenant);});
  }

  function handleAccountSettings() {
    setAccountOpen(false);
    navigate("/settings?section=profile");
  }

  function openMaintenanceSettings() {
    navigate("/admin?section=system-settings");
  }

  return (
    <header className="titlebar">
      {maintenanceMode?.enabled &&
      <button
        type="button"
        className="maintenance-topbar-link"
        title={maintenanceMode.message || translateText("i18n:govoplan-core.open_maintenance_mode_settings.99b41249")}
        onClick={openMaintenanceSettings}>
        
          {translateText("i18n:govoplan-core.maintenance_mode_enabled.4fb4a37d")}
        </button>
      }

      {auth && activeTenant && showTenantControl &&
      <div className="tenant-selector" ref={tenantRef}>
          <span className="tenant-label">{translateText("i18n:govoplan-core.tenant_label_prefix")}</span>
          {canSwitchTenant ?
        <>
              <button className="tenant-name-button" onClick={() => setTenantOpen(!tenantOpen)}>
                <strong>{activeTenant.name}</strong>
                <span className="tenant-caret">▾</span>
              </button>
              {tenantOpen &&
          <div className="dropdown-menu tenant-menu">
                  {tenants.map((tenant) => {
              const active = tenant.id === activeTenant.id;
              return (
                <button
                  key={tenant.id}
                  className={`dropdown-item ${active ? "active" : ""}`}
                  onClick={() => void handleTenantSelect(tenant)}
                  disabled={Boolean(switchingTenantId)}>
                  
                        <span>{switchingTenantId === tenant.id ? translateText("i18n:govoplan-core.switching.ca40b0ec") : tenant.name}</span>
                        {active && <Check size={16} />}
                      </button>);

            })}
                  {tenantError && <DismissibleAlert tone="danger" compact dismissible={false} className="dropdown-error">{tenantError}</DismissibleAlert>}
                </div>
          }
            </> :

        <strong>{activeTenant.name}</strong>
        }
        </div>
      }

      <div className="titlebar-spacer" />

      <HelpMenu />
      <LanguageMenu />

      <div className="context-menu-wrap" ref={accountRef}>
        <button className="account-pill" onClick={() => setAccountOpen(!accountOpen)}>
          <UserCircle size={22} />
          <span>{displayUserName}</span>
          <span className="tenant-caret">▾</span>
        </button>
        {accountOpen &&
        <div className="dropdown-menu account-menu">
            {auth ?
          <>
                {auth.user &&
                <div className="account-menu-header">
                  <strong>{auth.user.display_name || auth.user.email}</strong>
                  <span>{auth.user.email}</span>
                </div>
                }
                <button className="dropdown-item" onClick={handleAccountSettings}><Settings size={16} /> {translateText("i18n:govoplan-core.account_settings.82cf8a5f")}</button>
                <button className="dropdown-item" onClick={handleLogout}><LogOut size={16} /> {translateText("i18n:govoplan-core.sign_out.dc1649a1")}</button>
              </> :

          <button className="dropdown-item" onClick={() => {setLoginOpen(true);setAccountOpen(false);}}><UserCircle size={16} /> {translateText("i18n:govoplan-core.sign_in.ada2e9e9")}</button>
          }
          </div>
        }
      </div>

      {loginOpen && <LoginModal settings={settings} onClose={() => setLoginOpen(false)} onLogin={handleLogin} />}
    </header>);

}