import {
  ArrowLeftRight,
  BookOpen,
  Boxes,
  Building2,
  BarChart3,
  Container,
  FileSignature,
  FileText,
  Hammer,
  History,
  Landmark,
  LayoutDashboard,
  LayoutGrid,
  MapPin,
  Network,
  Package,
  PackageCheck,
  PackageOpen,
  Paperclip,
  Receipt,
  ScrollText,
  Send,
  Settings,
  ShieldCheck,
  Ship,
  SlidersHorizontal,
  Train,
  Truck,
  Users,
  Wallet,
  LifeBuoy,
  TrainFront,
  XCircle,
} from "lucide-react";

import type { AuthUser } from "@/auth/types";

import type { SidebarItem, SidebarSection } from "./types";
import {
  FREIGHT_PERMS,
  hasPermission as hasFreightPermission,
  isSuperAdmin,
} from "@/lib/permissions";
import { getCategorySidebarChildren } from "@/pages/ruleEngine/config/resources";

/**
 * Backoffice sidebar model: the nav tree, its permission filter, and the
 * flatten/lookup helpers. Lives outside App.tsx so `lib/landing.ts` can resolve
 * a user's first reachable route without importing the route tree (App.tsx
 * imports RequirePermission, which imports landing — that would cycle).
 */
export const buildSidebarSections = (demoItems: SidebarItem[]): SidebarSection[] => [
  {
    title: "Main menu",
    items: [
      {
        label: "Overview",
        href: "/dashboard/overview",
        icon: <LayoutDashboard />,
        permission: FREIGHT_PERMS.overview.view,
      },
      {
        label: "Reports",
        href: "/dashboard/reports",
        icon: <BarChart3 />,
        permission: FREIGHT_PERMS.reports.view,
      },
      {
        label: "Customers",
        href: "/dashboard/customers",
        icon: <Building2 />,
        permission: FREIGHT_PERMS.customers.view,
      },
      {
        label: "Contracts",
        href: "/dashboard/contract-requests",
        icon: <FileSignature />,
        permission: FREIGHT_PERMS.contracts.view,
      },
      {
        label: "Bookings",
        href: "/dashboard/booking-requests",
        icon: <FileText />,
        permission: FREIGHT_PERMS.bookings.view,
      },
      {
        label: "Wagon cancellations",
        href: "/dashboard/wagon-cancellations",
        icon: <XCircle />,
        permission: FREIGHT_PERMS.bookings.wagonCancellationView,
      },
      // Operations hub: per-shipment clearance-document review for services
      // WITHOUT customs clearing (self-clearance) — bookings only.
      {
        label: "Clearance Documents",
        href: "/dashboard/contracts/clearance-documents",
        icon: <ShieldCheck />,
        permission: FREIGHT_PERMS.contracts.opsClearanceReview,
      },
      {
        label: "Payments",
        href: "/dashboard/payments",
        icon: <Wallet />,
        permission: FREIGHT_PERMS.payments.view,
      },
      {
        label: "Invoices",
        href: "/dashboard/invoices",
        icon: <Receipt />,
        permission: FREIGHT_PERMS.invoices.view,
      },
      {
        label: "USD Payments",
        href: "/dashboard/usd-payments",
        icon: <Landmark />,
        permission: FREIGHT_PERMS.invoices.view,
      },
      {
        label: "Support",
        href: "/dashboard/support",
        icon: <LifeBuoy />,
        permission: FREIGHT_PERMS.support.agentView,
      },
      ...demoItems,
    ],
  },
  {
    // title: "Port & Terminal",
    items: [
      {
        label: "Operations",
        icon: <Settings />,
        children: [
          {
            label: "Clearance",
            href: "/dashboard/contracts/clearance",
            icon: <ShieldCheck />,
            permission: [
              FREIGHT_PERMS.contracts.clearanceReview,
              FREIGHT_PERMS.contracts.clearanceEtActions,
            ],
          },
          // {
          //   label: "Shipment Requests",
          //   href: "/dashboard/shipment-requests",
          //   icon: <Send />,
          //   permission: FREIGHT_PERMS.contracts.createBooking,
          // },
          // Operations Path A queue: per-booking self-clearance review for
          // GENERAL non-customs booking instances (and legacy self-clear bookings).
          // {
          //   label: "Self-Clearance Review",
          //   href: "/dashboard/contracts/ops-clearance",
          //   icon: <ShieldCheck />,
          //   permission: FREIGHT_PERMS.contracts.opsClearanceReview,
          // },
          {
            label: "GL Djibouti Clearance",
            href: "/dashboard/gl-djibouti/clearance",
            icon: <Ship />,
            permission: FREIGHT_PERMS.contracts.clearanceDjActions,
          },
          {
            label: "Train Schedules",
            href: "/dashboard/operations/train-scheduling-v2",
            icon: <Train />,
            permission: FREIGHT_PERMS.trainScheduling.view,
          },
          {
            label: "Batch Board",
            href: "/dashboard/operations/batch-board",
            icon: <LayoutGrid />,
            permission: FREIGHT_PERMS.trainScheduling.view,
          },
          {
            label: "First Mile",
            href: "/dashboard/operations/first-mile",
            icon: <Truck />,
            permission: FREIGHT_PERMS.firstMile.view,
          },
          {
            label: "Last Mile",
            href: "/dashboard/operations/last-mile",
            icon: <Truck />,
            permission: FREIGHT_PERMS.lastMile.view,
          },
        ],
      },
      {
        label: "Fleet Management",
        icon: <Truck />,
        children: [
          {
            label: "Fleet Dashboard",
            href: "/dashboard/fleet-dashboard",
            icon: <LayoutDashboard />,
            permission: FREIGHT_PERMS.fleetDashboard.view,
          },
          {
            label: "Routes",
            href: "/dashboard/routes",
            icon: <Network />,
            permission: FREIGHT_PERMS.routes.view,
          },
          {
            label: "Locomotives",
            href: "/dashboard/locomotives",
            icon: <Train />,
            permission: FREIGHT_PERMS.locomotives.view,
          },
          {
            label: "Train Builder",
            href: "/dashboard/train-builder",
            icon: <Hammer />,
            permission: FREIGHT_PERMS.trains.view,
          },

          // {
          //   label: "Wagon types",
          //   href: "/dashboard/wagon-types",
          //   icon: <Boxes />,
          // },
          {
            label: "Wagons",
            href: "/dashboard/wagons",
            icon: <Truck />,
            permission: FREIGHT_PERMS.wagons.view,
          },
          {
            label: "Wagon Transfers",
            href: "/dashboard/wagon-transfers",
            icon: <ArrowLeftRight />,
            permission: [
              FREIGHT_PERMS.wagons.transferView,
              FREIGHT_PERMS.wagons.view,
            ],
          },
          {
            label: "Vehicles",
            href: "/dashboard/vehicles",
            icon: <Truck />,
            permission: FREIGHT_PERMS.vehicles.view,
          },
          {
            label: "Drivers",
            href: "/dashboard/drivers",
            icon: <Users />,
            permission: FREIGHT_PERMS.drivers.view,
          },
          {
            label: "Track Vehicles",
            href: "/dashboard/tracking",
            icon: <MapPin />,
            permission: FREIGHT_PERMS.tracking.view,
          },
          {
            label: "Fuel Purchases",
            href: "/dashboard/fuel-purchases",
            icon: <Truck />,
            permission: FREIGHT_PERMS.fuel.view,
          },
          {
            label: "Fuel Analytics",
            href: "/dashboard/fuel-stats",
            icon: <Truck />,
            permission: FREIGHT_PERMS.fuel.view,
          },
          {
            label: "Maintenance",
            href: "/dashboard/maintenance",
            icon: <Truck />,
            permission: FREIGHT_PERMS.maintenance.view,
          },
          {
            label: "Work Orders",
            href: "/dashboard/work-orders",
            icon: <SlidersHorizontal />,
            permission: FREIGHT_PERMS.maintenance.view,
          },
          {
            label: "Compliance & Alerts",
            href: "/dashboard/compliance",
            icon: <ShieldCheck />,
            permission: FREIGHT_PERMS.compliance.view,
          },
          {
            label: "Incidents",
            href: "/dashboard/incidents",
            icon: <FileText />,
            // No dedicated backend key exists for incidents yet. Not part of
            // the fleet.view/admin fallback cleanup — removing fleet.view
            // here with nothing to replace it would lock the page to
            // super-admin only, so it stays as the sole (if coarse) gate.
            permission: FREIGHT_PERMS.fleet.view,
          },
          {
            label: "Procurement",
            href: "/dashboard/procurement",
            icon: <Package />,
            permission: FREIGHT_PERMS.procurement.view,
          },
          {
            label: "Financial Reports",
            href: "/dashboard/financial-reports",
            icon: <Wallet />,
            permission: FREIGHT_PERMS.fleetReports.view,
          },
          // {
          //   label: "Containers",
          //   href: "/dashboard/containers",
          //   icon: <Container />,
          // },
          // {
          //   label: "Cargoes",
          //   href: "/dashboard/cargoes",
          //   icon: <Package />,
          // },
        ],
      },
      {
        label: "Imports",
        href: "/dashboard/import-warehouse",
        icon: <PackageOpen />,
        permission: FREIGHT_PERMS.warehouseInventory.view,
        children: [
          {
            label: "Import Overview",
            href: "/dashboard/import-warehouse",
            icon: <PackageOpen />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Arrival Queue",
            href: "/dashboard/arrival-queue",
            icon: <PackageOpen />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Import Trucks",
            href: "/dashboard/import-trucks",
            icon: <Truck />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Container Returns",
            href: "/dashboard/container-returns",
            icon: <Container />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Terminal Inventory",
            href: "/dashboard/warehouse-inventory?direction=IMPORT",
            icon: <Package />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Inventory Inquiry",
            href: "/dashboard/inventory-inquiry",
            icon: <Boxes />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
        ],
      },
      {
        label: "Exports",
        href: "/dashboard/export-warehouse",
        icon: <Truck />,
        permission: FREIGHT_PERMS.warehouseInventory.view,
        children: [
          {
            label: "Export Overview",
            href: "/dashboard/export-warehouse",
            icon: <Truck />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Loading Queue",
            href: "/dashboard/loading-queue",
            icon: <Truck />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Loaded Inventory",
            href: "/dashboard/loaded-inventory",
            icon: <PackageCheck />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Dispatch Queue",
            href: "/dashboard/dispatch-queue",
            icon: <Send />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Djibouti Unloading",
            href: "/dashboard/export-djibouti-unloading",
            icon: <PackageOpen />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Interchange Documents",
            href: "/dashboard/interchange-documents",
            icon: <FileText />,
            permission: FREIGHT_PERMS.interchangeDocuments.view,
          },
          {
            label: "Terminal Inventory",
            href: "/dashboard/warehouse-inventory?direction=EXPORT",
            icon: <Package />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
        ],
      },
      {
        label: "Intercity",
        href: "/dashboard/intercity",
        icon: <TrainFront />,
        permission: FREIGHT_PERMS.trainScheduling.view,
        children: [
          {
            label: "Intercity Cargo",
            href: "/dashboard/intercity",
            icon: <TrainFront />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
        ],
      },
      {
        label: "Warehouse Management",
        icon: <Container />,
        children: [
          {
            label: "Warehouse Dashboard",
            href: "/dashboard/warehouse-dashboard",
            icon: <LayoutDashboard />,
            permission: FREIGHT_PERMS.warehouseDashboard.view,
          },
          {
            // Yard-wide, not per-direction: the gate sees import and export
            // trucks at the same barrier.
            label: "Trucks on Site",
            href: "/dashboard/trucks-on-site",
            icon: <Truck />,
            permission: FREIGHT_PERMS.warehouseInventory.view,
          },
          {
            label: "Warehouses",
            href: "/dashboard/warehouses",
            icon: <Container />,
            permission: FREIGHT_PERMS.warehouses.view,
          },
          {
            label: "Allocation & Fees",
            href: "/dashboard/warehouse-rules",
            icon: <SlidersHorizontal />,
            permission: [
              FREIGHT_PERMS.warehouseAllocationRules.view,
              FREIGHT_PERMS.warehouseFeeRules.view,
            ],
          },
          {
            label: "Fee Invoices",
            href: "/dashboard/warehouse-fee-invoices",
            icon: <Wallet />,
            permission: FREIGHT_PERMS.warehouseFeeInvoices.view,
          },
        ],
      },
    ],
  },
  {
    title: "Freight configuration",
    mutedTitle: true,
    items: [
      {
        label: "File settings",
        href: "/dashboard/file-settings",
        icon: <Paperclip />,
        permission: FREIGHT_PERMS.settings.fileUpload.view,
      },
      {
        label: "Dropdown settings",
        href: "/dashboard/dropdown-settings",
        icon: <Settings />,
        permission: FREIGHT_PERMS.settings.dropdown.view,
      },
      {
        label: "Stamp settings",
        href: "/dashboard/stamp-settings",
        icon: <FileSignature />,
        permission: FREIGHT_PERMS.settings.stamp.view,
      },
      {
        label: "Invoice stamp",
        href: "/dashboard/invoice-stamp-settings",
        icon: <Receipt />,
        permission: FREIGHT_PERMS.settings.invoiceStamp.view,
      },
      {
        label: "Contract templates",
        href: "/dashboard/contract-templates",
        icon: <ScrollText />,
        // `view` opens the page; `read` alone is API-only and shows no menu.
        permission: FREIGHT_PERMS.settings.contractTemplates.view,
      },
      {
        label: "Portal content",
        href: "/dashboard/portal-content",
        icon: <BookOpen />,
        permission: [
          FREIGHT_PERMS.settings.supportContent.view,
          FREIGHT_PERMS.settings.supportContent.manage,
        ],
      },
      {
        label: "Audit logs",
        href: "/dashboard/audit-logs",
        icon: <History />,
        permission: FREIGHT_PERMS.auditLog.view,
      },
      {
        label: "Configuration",
        href: "/dashboard/configuration",
        icon: <Boxes />,
        children: [
          ...getCategorySidebarChildren("configuration"),
          {
            label: "Train scheduling rules",
            href: "/dashboard/configuration/train-scheduling-rules",
            permission: FREIGHT_PERMS.trainScheduling.rulesManage,
          },
          {
            label: "Trade access",
            href: "/dashboard/configuration/trade-access",
            permission: FREIGHT_PERMS.tradeAccess.view,
          },
          {
            label: "Exchange rate",
            href: "/dashboard/configuration/exchange-rate",
            permission: FREIGHT_PERMS.settings.exchangeRate.view,
          },
        ],
      },
      {
        label: "Rules",
        href: "/dashboard/rules",
        icon: <SlidersHorizontal />,
        children: getCategorySidebarChildren("rules"),
      },

      {
        label: "Staff",
        href: "/user-management",
        icon: <Users />,
        permission: [
          FREIGHT_PERMS.admin,
          FREIGHT_PERMS.staff.roles.view,
          FREIGHT_PERMS.staff.employeeRegistration.view,
          FREIGHT_PERMS.staff.roleAssignment.view,
        ],
      },
    ],
  },
];

/**
 * Keep only items the user is permitted to see; drop now-empty sections.
 * Super Admin sees everything; everyone else is filtered purely by each
 * item's `permission` field (OR across the array when one is given).
 */
export const filterSidebarByPermission = (
  sections: SidebarSection[],
  user: AuthUser | null | undefined,
): SidebarSection[] => {
  // Superadmin sees every section and item — no permission filtering.
  if (isSuperAdmin(user)) return sections;

  const permissionAllowed = (item: SidebarItem): boolean => {
    if (!item.permission) return true;
    const keys = Array.isArray(item.permission)
      ? item.permission
      : [item.permission];
    return keys.some((key) => hasFreightPermission(user, key));
  };

  // Recursive: children are filtered first; a group (item with children) stays
  // only while it still has visible children — so parents without their own
  // permission key never leak a whole subtree the user cannot open.
  const filterItems = (items: SidebarItem[]): SidebarItem[] =>
    items
      .map((item) =>
        item.children
          ? { ...item, children: filterItems(item.children) }
          : item,
      )
      .filter((item) => {
        if (!permissionAllowed(item)) return false;
        if (item.children) return item.children.length > 0;
        return true;
      });

  return sections
    .map((section) => ({
      ...section,
      items: filterItems(section.items),
    }))
    .filter((section) => section.items.length > 0);
};

export const APP_TITLE = "EDR Freight Backoffice";

/** Flatten sidebar sections (incl. nested children) into {href, label} pairs. */
export const flattenSidebarItems = (
  sections: SidebarSection[],
): { href: string; label: string }[] =>
  sections.flatMap((section) =>
    section.items.flatMap((item) => [
      ...(item.href ? [{ href: item.href, label: item.label }] : []),
      ...(item.children ?? [])
        .filter((child): child is SidebarItem & { href: string } =>
          Boolean(child.href),
        )
        .map((child) => ({ href: child.href, label: child.label })),
    ]),
  );

/** Find the sidebar label whose href matches (exactly or as a prefix of) the current path. */
export const findActiveSidebarLabel = (
  pathname: string,
  sections: SidebarSection[],
): string | undefined => {
  const path = pathname.toLowerCase();
  const candidates = flattenSidebarItems(sections)
    .map(({ href, label }) => ({
      label,
      href: href.split("?")[0].toLowerCase(),
    }))
    .sort((a, b) => b.href.length - a.href.length);

  return candidates.find(
    ({ href }) => path === href || path.startsWith(`${href}/`),
  )?.label;
};