import { NavLink, useLocation } from "react-router-dom";
import { useQuery } from "@tanstack/react-query";
import { fetchSystemNavigation, type NavigationItem } from "../../api/workspace";
import { useAuth } from "../../auth/AuthContext";
import { hasAnyPermission, hasBusinessApproverRole, hasFinanceRole } from "../../auth/permissions";
import {
  ADMIN_NAV_ORDER,
  BACKUP_NAV_ORDER,
  MAIN_NAV_ORDER,
} from "../../features/navigation/schema";
import {
  isManagementPath,
  MANAGEMENT_ROOT_PERMISSIONS,
} from "../../features/navigation/managementRoutes";
import { cn } from "../../lib/utils";

export type NavItem = {
  to: string;
  label: string;
  icon: string;
  anyOf?: string[];
};

export const NAV_ITEMS: NavItem[] = [
  { to: "/portal", label: "工作台", icon: "home_app_logo" },
  { to: "/team", label: "团队", icon: "groups", anyOf: ["report.dashboard.view", "project.view_all", "project.manage", "system.users"] },
  { to: "/leave-requests", label: "请假记录", icon: "event_available", anyOf: ["leave.view_own", "leave.view_all", "leave.manage"] },
  { to: "/attendance", label: "考勤", icon: "schedule" },
  { to: "/reimbursements", label: "报销", icon: "request_quote", anyOf: ["expense.view_own", "expense.view_all"] },
  { to: "/assets", label: "资产", icon: "inventory_2", anyOf: ["asset.view_own", "asset.view_all", "asset.manage", "asset.transfer", "asset.inventory"] },
  { to: "/weekly-reports", label: "周报", icon: "article" },
  { to: "/announcements", label: "公告", icon: "campaign" },
  { to: "/projects", label: "项目", icon: "workspaces", anyOf: ["project.view_own", "project.view_all", "project.manage"] },
  { to: "/system/settings", label: "管理", icon: "settings", anyOf: MANAGEMENT_ROOT_PERMISSIONS },
  { to: "/workflow/tasks", label: "待我审批", icon: "fact_check", anyOf: ["expense.approve", "leave.approve", "attendance.approve", "procurement.approve", "travel.approve"] },
  { to: "/contracts-registry", label: "合同", icon: "description", anyOf: ["project.view_all", "project.manage", "system.settings"] },
  { to: "/purchase-requests", label: "采购", icon: "shopping_cart", anyOf: ["procurement.create", "procurement.view_own", "procurement.view_all", "procurement.manage"] },
  { to: "/travel-requests", label: "差旅申请", icon: "flight", anyOf: ["travel.view_all", "travel.manage", "travel.payment.manage"] },
  { to: "/budgets", label: "预算管理", icon: "account_balance", anyOf: ["budget.view", "budget.manage"] },
  { to: "/payment-batches", label: "付款", icon: "payments", anyOf: ["payment.batch.manage", "risk.review.manage", "payment.batch.review"] },
  { to: "/ap-operations", label: "应付账款", icon: "account_balance_wallet", anyOf: ["payment.batch.manage", "risk.review.manage", "payment.batch.review"] },
  { to: "/invoice-pool", label: "票据", icon: "receipt_long", anyOf: ["invoice.manage"] },
  { to: "/inventory-checks", label: "资产盘点", icon: "inventory", anyOf: ["asset.inventory"] },
  { to: "/dashboard", label: "数据看板", icon: "dashboard", anyOf: ["report.dashboard.view"] },
];

const ACCESSIBLE_LABELS: Record<string, string> = {
  "/reimbursements": "我的报销",
  "/workflow/tasks": "待我审批",
  "/assets": "资产",
};

const PRODUCT_LABELS: Record<string, string> = {
  "/workflow/tasks": "待我审批",
};

const TEAM_NAVIGATION_ROLE_CODES = ["manager", "ceo", "finance_mgr", "hr", "admin"];
const PAYMENT_REVIEWER_ROLE_CODES = ["manager", "ceo"];

function hasPaymentReviewRole(roleCodes: string[], permissions: string[]) {
  return roleCodes.some((roleCode) => PAYMENT_REVIEWER_ROLE_CODES.includes(roleCode)) &&
    hasAnyPermission(permissions, ["payment.batch.review"]);
}

type ResolvedNavItem = {
  key?: string;
  href: string;
  label: string;
  icon: string;
};

function isGroupedActive(item: ResolvedNavItem, pathname: string, permissions: string[]) {
  if (item.href === "/system/settings") {
    return isManagementPath(pathname, permissions);
  }

  return pathname === item.href || pathname.startsWith(`${item.href}/`);
}

function renderNavItem(item: ResolvedNavItem, pathname: string, permissions: string[], onNavigate?: () => void) {
  const accessibleLabel = ACCESSIBLE_LABELS[item.href] ?? item.label;

  return (
    <NavLink
      key={item.key ?? item.href}
      to={item.href}
      aria-label={accessibleLabel}
      title={accessibleLabel}
      onClick={() => onNavigate?.()}
      className={({ isActive }) =>
        cn("group nav-link-item", isActive || isGroupedActive(item, pathname, permissions) ? "nav-link-item--active" : "nav-link-item--idle")
      }
    >
      {({ isActive }) => {
        const active = isActive || isGroupedActive(item, pathname, permissions);
        return (
          <>
            <span className={cn("nav-link-item__icon", active ? "nav-link-item__icon--active" : "nav-link-item__icon--idle")}>
              <span className="material-symbols-outlined text-[20px]">{item.icon}</span>
            </span>
            <span className="min-w-0 flex-1 truncate font-medium">{item.label}</span>
          </>
        );
      }}
    </NavLink>
  );
}

function renderPrimarySection(items: ResolvedNavItem[], pathname: string, permissions: string[], onNavigate?: () => void) {
  if (!items.length) {
    return null;
  }

  return (
    <section className="nav-section">
      <div className="space-y-1.5">{items.map((item) => renderNavItem(item, pathname, permissions, onNavigate))}</div>
    </section>
  );
}

function renderBackupSection(items: ResolvedNavItem[], pathname: string, permissions: string[], onNavigate?: () => void) {
  if (!items.length) {
    return null;
  }

  return (
    <details className="nav-more-section">
      <summary className="nav-more-section__summary">
        <span className="nav-link-item__icon nav-link-item__icon--idle">
          <span className="material-symbols-outlined text-[20px]">more_horiz</span>
        </span>
        <span className="min-w-0 flex-1 truncate font-medium">更多</span>
        <span className="material-symbols-outlined nav-more-section__chevron">expand_more</span>
      </summary>
      <div className="mt-1.5 space-y-1.5 pb-1">{items.map((item) => renderNavItem(item, pathname, permissions, onNavigate))}</div>
    </details>
  );
}

function buildFallbackItems(permissions: string[], roleCodes: string[]) {
  const paymentPaths = new Set(["/payment-batches", "/ap-operations"]);
  const financeOnlyPaths = new Set(["/invoice-pool"]);
  const backupOnlyPaths = new Set(BACKUP_NAV_ORDER);
  const mapItems = (paths: string[]) =>
    NAV_ITEMS.filter((item) => paths.includes(item.to))
      .filter((item) => item.to !== "/workflow/tasks" || hasBusinessApproverRole(roleCodes, permissions))
      .filter((item) => item.to !== "/team" || roleCodes.some((roleCode) => TEAM_NAVIGATION_ROLE_CODES.includes(roleCode)))
      .filter((item) => !paymentPaths.has(item.to) || hasFinanceRole(roleCodes, permissions) || hasPaymentReviewRole(roleCodes, permissions))
      .filter((item) => !financeOnlyPaths.has(item.to) || hasFinanceRole(roleCodes, permissions))
      .filter((item) => !item.anyOf || hasAnyPermission(permissions, item.anyOf))
      .filter((item) => paths === BACKUP_NAV_ORDER || !backupOnlyPaths.has(item.to))
      .map((item) => ({ key: item.to, href: item.to, label: item.label, icon: item.icon }));

  return {
    main: mapItems(MAIN_NAV_ORDER),
    admin: mapItems(ADMIN_NAV_ORDER),
    backup: mapItems(BACKUP_NAV_ORDER),
  };
}

function orderItems(items: ResolvedNavItem[], order: string[]) {
  const byHref = new Map<string, ResolvedNavItem>();
  for (const item of items) {
    if (!byHref.has(item.href)) {
      byHref.set(item.href, item);
    }
  }

  const used = new Set<string>();
  const ordered = order
    .map((href) => {
      const item = byHref.get(href);
      if (item) {
        used.add(href);
      }
      return item;
    })
    .filter((item): item is ResolvedNavItem => Boolean(item));

  return [...ordered, ...items.filter((item) => !used.has(item.href))];
}

function toResolved(items: NavigationItem[]) {
  return items.map((item) => ({
    key: item.key,
    href: item.href,
    label: PRODUCT_LABELS[item.href] ?? item.label,
    icon: item.icon,
  }));
}

function normalizeSections(sections: { main: NavigationItem[]; admin: NavigationItem[]; backup: NavigationItem[] }) {
  return {
    main: orderItems(toResolved(sections.main), MAIN_NAV_ORDER),
    admin: orderItems(toResolved(sections.admin), ADMIN_NAV_ORDER),
    backup: orderItems(toResolved(sections.backup), BACKUP_NAV_ORDER),
  };
}

function normalizeManagementRoot(
  sections: { main: ResolvedNavItem[]; admin: ResolvedNavItem[]; backup: ResolvedNavItem[] },
  permissions: string[],
) {
  const canAccessManagement = hasAnyPermission(permissions, MANAGEMENT_ROOT_PERMISSIONS);
  const withoutManagement = sections.admin.filter((item) => item.href !== "/system/settings");
  return {
    ...sections,
    admin: canAccessManagement
      ? [{ key: "/system/settings", href: "/system/settings", label: "管理", icon: "settings" }, ...withoutManagement]
      : withoutManagement,
  };
}

export function NavLinks({ onNavigate }: { onNavigate?: () => void }) {
  const { me, permissions } = useAuth();
  const location = useLocation();
  const navigationQuery = useQuery({
    queryKey: ["system-navigation"],
    queryFn: fetchSystemNavigation,
    staleTime: 60_000,
  });

  const baseSections = navigationQuery.data?.sections
    ? normalizeSections(navigationQuery.data.sections)
    : buildFallbackItems(permissions, me?.roleCodes ?? []);
  const sections = normalizeManagementRoot(baseSections, permissions);
  const primaryItems = [...sections.main, ...sections.admin];

  return (
    <nav className="space-y-3.5">
      {renderPrimarySection(primaryItems, location.pathname, permissions, onNavigate)}
      {renderBackupSection(sections.backup, location.pathname, permissions, onNavigate)}
    </nav>
  );
}