import { useState, useEffect } from "react";
import { Link, Outlet, useLocation } from "react-router-dom";
import { API_URL, getToken, getUsername, getCompany } from "../utils/api";
import Icon from "../components/ui/Icon";

// Estructura del menú tipada para SAP Business One
interface SubMenuItem {
  name: string;
  path: string;
}

interface MenuItem {
  title: string;
  icon: string;
  subItems: SubMenuItem[];
}

const menuConfig: MenuItem[] = [
  {
    title: "0. Dashboard",
    icon: "chart",
    subItems: [{ name: "Inicio", path: "/dashboard" }],
  },
  {
    title: "1. Inventario",
    icon: "box",
    subItems: [
      { name: "Articulos", path: "/inventario/articulos" },
      { name: "Lotes", path: "/inventario/lotes" },
      { name: "Inmovilizar Lotes", path: "/inventario/inmovilizar-lotes" },
      { name: "Liberar Lotes", path: "/inventario/liberar-lotes" },
      { name: "Confirmar Liberación Lote", path: "/inventario/confirmar-liberacion-lote" },
    ],
  },
  {
    title: "2. Socio de negocios",
    icon: "users",
    subItems: [
      { name: "Clientes", path: "/socios/clientes" },
      { name: "Proveedores", path: "/socios/proveedores" },
    ],
  },
  {
    title: "3. Ventas",
    icon: "cart",
    subItems: [
      { name: "Ordenes de venta", path: "/ventas/ordenes" },
      { name: "Entregas o Guías", path: "/ventas/entrega" },
      { name: "Facturas de venta", path: "/ventas/facturas" },
    ],
  },
  {
    title: "4. Compras",
    icon: "briefcase",
    subItems: [
      { name: "Ordenes de compra", path: "/compras/ordenes" },
      { name: "Recepciones de compras", path: "/compras/recepcion" },
      { name: "Facturas de proveedores", path: "/compras/facturas" },
    ],
  },
  {
    title: "5. Informes",
    icon: "chart",
    subItems: [
      { name: "Socios de negocios", path: "/informes/socios" },
      { name: "Ventas", path: "/informes/ventas" },
      { name: "Compras", path: "/informes/compras" },
      { name: "Inventario", path: "/informes/inventario" },
    ],
  },
  {
    title: "6. Reportes Crystal",
    icon: "chart",
    subItems: [
      { name: "Socios de negocios", path: "/reportes-crystal/socios" },
      { name: "Ventas", path: "/reportes-crystal/ventas" },
      { name: "Compras", path: "/reportes-crystal/compras" },
      { name: "Inventario", path: "/reportes-crystal/inventario" },
    ],
  },
  {
    title: "7. Reportes HTML",
    icon: "tag",
    subItems: [
      { name: "Socios de negocios", path: "/reportes-html/socios" },
      { name: "Ventas", path: "/reportes-html/ventas" },
      { name: "Compras", path: "/reportes-html/compras" },
      { name: "Inventario", path: "/reportes-html/inventario" },
    ],
  },
];

export default function MainLayout() {
  const location = useLocation();
  const [isSidebarOpen, setIsSidebarOpen] = useState<boolean>(true);
  const [currentTheme, setCurrentTheme] = useState<string>(
    () => localStorage.getItem("sap_theme") || "theme-default",
  );
  const [openModules, setOpenModules] = useState<Record<string, boolean>>({
    "1. Inventario": true,
    "2. Socio de negocios": true,
    "5. Informes": true,
  });
  const [allowedPaths, setAllowedPaths] = useState<string[] | null>(null);
  const [permissionsError, setPermissionsError] = useState(false);

  useEffect(() => {
    const fetchPermissions = async () => {
      const token = getToken();
      if (!token) return;
      try {
        const res = await fetch(`${API_URL}/api/user/menu`, {
          headers: { "X-Session-Token": token },
        });
        if (!res.ok) throw new Error("No se pudo cargar el menú");
        const data = await res.json();
        setAllowedPaths(data.allowedPaths);
      } catch {
        setPermissionsError(true);
      }
    };
    fetchPermissions();
  }, []);

  useEffect(() => {
    document.documentElement.className = currentTheme;
    localStorage.setItem("sap_theme", currentTheme);
  }, [currentTheme]);

  const pathMatches = (path: string) => {
    if (!allowedPaths) return false;
    return allowedPaths.some(
      (p) =>
        p === "*" ||
        (p.endsWith("/*") && path.startsWith(p.slice(0, -2))) ||
        p === path,
    );
  };

  const toggleModule = (title: string) => {
    setOpenModules((prev) => ({ ...prev, [title]: !prev[title] }));
  };

  const username = getUsername();
  const company = getCompany();

  const handleLogout = async () => {
    const token = getToken();
    if (token) {
      try {
        await fetch(`${API_URL}/api/Logout`, {
          method: "POST",
          headers: { "X-Session-Token": token },
        });
      } catch {
        /* ignore */
      }
    }
    localStorage.removeItem("sap_session");
    window.location.href = "/login";
  };

  return (
    <div className="flex h-screen w-screen overflow-hidden bg-[var(--color-bg)] font-sans antialiased text-[var(--color-text)]">
      {/* Menu lateral (Sidebar) */}
      <aside
        className={`border-r border-[var(--color-border)] bg-[var(--color-surface)] flex flex-col shrink-0 select-none transition-none ${
          isSidebarOpen ? "w-64" : "w-12"
        }`}
      >
        {/* Encabezado del Menú */}
        <div className="h-12 border-b border-[var(--color-border)] flex items-center px-3 justify-between bg-[var(--color-bg)]">
          {isSidebarOpen && (
            <span className="text-xs font-bold uppercase tracking-wider text-[var(--color-sidebar-title)]">
              Main Menu
            </span>
          )}
          <button
            onClick={() => setIsSidebarOpen(!isSidebarOpen)}
            className="text-sm font-medium p-1 hover:bg-[var(--color-sidebar-hover)] cursor-pointer text-[var(--color-sidebar-title)] border-none"
            title="Alternar Menú"
          >
            {isSidebarOpen ? "◀" : "▶"}
          </button>
        </div>

        {/* Listado Jerárquico de Módulos */}
        <nav className="flex-1 overflow-y-auto overflow-x-hidden py-2 space-y-1">
          {permissionsError && isSidebarOpen && (
            <div className="mx-2 my-1 p-2 text-[11px] text-[var(--color-error)] bg-[var(--color-error-bg)] border border-[var(--color-error-border)]">
              No se pudo cargar el menú. Intenta recargar la página.
            </div>
          )}
          {menuConfig
            .map((module) => ({
              ...module,
              subItems: module.subItems.filter((sub) => pathMatches(sub.path)),
            }))
            .filter((module) => module.subItems.length > 0)
            .map((module) => {
              const isOpen = openModules[module.title];
              return (
                <div key={module.title} className="w-full">
                  {/* Nivel 1: Módulo */}
                  <button
                    onClick={() => isSidebarOpen && toggleModule(module.title)}
                    className={`w-full flex items-center px-3 py-2 text-xs font-semibold text-[var(--color-sidebar-title)] border-none text-left cursor-pointer ${
                      isSidebarOpen
                        ? "hover:bg-[var(--color-sidebar-hover)]"
                        : "justify-center hover:bg-[var(--color-sidebar-hover)]"
                    }`}
                    disabled={!isSidebarOpen}
                  >
                    <Icon name={module.icon} className="w-4 h-4 shrink-0" />
                    {isSidebarOpen && (
                      <>
                        <span className="ml-2 flex-1 truncate">
                          {module.title}
                        </span>
                        <span className="text-[9px] text-[var(--color-text-muted)]">
                          {isOpen ? "▼" : "▶"}
                        </span>
                      </>
                    )}
                  </button>

                  {/* Nivel 2: Submódulos (Solo si está expandido y el menú está abierto) */}
                  {isSidebarOpen && isOpen && (
                    <div className="bg-[var(--color-sidebar-submenu-bg)] border-y border-[var(--color-sidebar-submenu-border)] py-1">
                      {module.subItems.map((subItem) => {
                        const isActive = location.pathname === subItem.path;
                        return (
                          <Link
                            key={subItem.path}
                            to={subItem.path}
                            className={`block pl-8 pr-3 py-1.5 text-xs truncate border-l-2 decoration-transparent ${
                              isActive
                                ? "border-[var(--color-primary)] bg-[var(--color-primary-active)] text-[var(--color-primary)] font-medium"
                                : "border-transparent text-[var(--color-sidebar-text)] hover:bg-[var(--color-sidebar-hover)]"
                            }`}
                          >
                            {subItem.name}
                          </Link>
                        );
                      })}
                    </div>
                  )}
                </div>
              );
            })}
        </nav>
      </aside>

      {/* Contenedor principal */}
      <div className="flex-1 flex flex-col overflow-hidden">
        {/* Barra superior (TopBar Flat) */}
        <header className="h-12 border-b border-[var(--color-border)] bg-[var(--color-header-bg)] text-white flex items-center justify-between px-4 select-none">
          <div className="flex items-center space-x-3">
            <span className="font-bold text-base tracking-tight">SAP</span>
            <span className="text-xs text-[var(--color-header-muted)] border-l border-[var(--color-header-border)] pl-3 font-normal">
              Web Client — {company || "SAP Business One"}
            </span>
          </div>

          <div className="flex items-center space-x-4 text-xs">
            <div className="flex items-center space-x-1.5">
              <span className="text-[var(--color-header-muted)]">Usuario:</span>
              <span className="font-medium">{username || "manager"}</span>
            </div>
            <select
              value={currentTheme}
              onChange={(e) => setCurrentTheme(e.target.value)}
              className="bg-transparent border border-[var(--color-header-border)] text-white px-2 py-1 text-[11px] cursor-pointer rounded-none outline-none"
            >
              <option value="theme-default" className="text-black">
                Default
              </option>
              <option value="theme-flat-light" className="text-black">
                Flat Light
              </option>
              <option value="theme-enterprise" className="text-black">
                Enterprise
              </option>
              <option value="theme-ocean" className="text-black">
                Ocean
              </option>
              <option value="theme-slate" className="text-black">
                Slate
              </option>
              <option value="theme-terra" className="text-black">
                Terra
              </option>
            </select>
            <button
              onClick={handleLogout}
              className="bg-transparent border border-[var(--color-header-border)] hover:bg-[var(--color-danger-hover)] text-white px-2 py-1 text-[11px] font-medium cursor-pointer rounded-none"
            >
              Cerrar Sesión
            </button>
          </div>
        </header>

        {/* Espacio de trabajo (Renderiza cada submódulo) */}
        <main className="flex-1 overflow-auto bg-[var(--color-surface)]">
          <Outlet />
        </main>
      </div>
    </div>
  );
}