/**
 * @file Navbar.tsx
 * @description Client component providing responsive navigation for desktop and mobile views with active route indicators and trash count.
 */

"use client";

import Link from "next/link";
import { usePathname } from "next/navigation";
import { LayoutDashboard, FileText, Trash2, FilePenLine } from "lucide-react";
import useSWR from "swr";

const fetcher = (url: string) => fetch(url).then((res) => res.json());

/**
 * Array of navigation items containing their name, route path, and corresponding icon.
 */
const navItems = [
  { name: "Summary", href: "/summary", icon: FileText },
  { name: "Dashboard", href: "/dashboard", icon: LayoutDashboard },
  { name: "Add Task", href: "/tasks", icon: FilePenLine },
  { name: "Trash", href: "/trash", icon: Trash2 },
];

/**
 * Renders the responsive navigation bar featuring desktop sidebar layout
 * and mobile bottom bar layout with active state styling and cached trash counter.
 *
 * @returns {JSX.Element} The rendered navigation component.
 */
export default function Navbar() {
  const pathname = usePathname();

  const { data } = useSWR("/api/trash/count", fetcher, {
    revalidateOnFocus: false,
    revalidateIfStale: false,
  });

  const trashCount = data?.count || 0;

  // Shared function to render navigation links
  const renderNavLinks = (isMobile = false) =>
    navItems.map((item) => {
      const Icon = item.icon;
      const isTrash = item.href === "/trash";
      const isActive =
        pathname === item.href ||
        (item.href !== "/" && pathname.startsWith(item.href));

      return (
        <Link
          key={item.href}
          href={item.href === "/tasks" ? "/tasks?task=new" : item.href}
          aria-current={isActive ? "page" : undefined}
          className={
            isMobile
              ? `flex flex-col items-center justify-center gap-1 transition-colors ${
                  isActive
                    ? "cursor-default pointer-events-none"
                    : "text-foreground-muted hover:text-foreground"
                }`
              : `flex items-center gap-3 px-3 py-2 rounded-lg font-medium transition-colors ${
                  isActive
                    ? "bg-foreground/10 cursor-default pointer-events-none"
                    : "text-foreground-muted hover:text-foreground hover:bg-foreground/5"
                }`
          }
        >
          <div className="relative inline-flex items-center">
            <Icon
              className={`${isMobile ? "w-5 h-5" : "w-4 h-4"} ${isActive ? "text-primary" : ""}`}
            />
            {isTrash && trashCount > 0 && (
              <span className="absolute -top-1.5 -right-2 flex h-3.5 w-3.5 items-center justify-center rounded-full bg-destructive text-[9px] font-bold text-white shadow-sm ring-1 ring-background">
                {trashCount}
              </span>
            )}
          </div>

          <span className={isMobile ? "text-xs font-medium" : ""}>
            {item.name}
          </span>
        </Link>
      );
    });

  return (
    <>
      {/* Desktop Navigation */}
      <nav className="hidden md:flex flex-col mt-6 space-y-1">
        {renderNavLinks(false)}
      </nav>

      {/* Mobile Navigation */}
      <nav className="md:hidden h-16 border-t border-border backdrop-blur-xl px-6 flex items-center justify-around fixed bottom-0 left-0 right-0 z-50 bg-background-muted">
        {renderNavLinks(true)}
      </nav>
    </>
  );
}