"use client";

import Link from "next/link";
import { usePathname } from "next/navigation";
import { useAuth } from "./auth-provider";
import { useTheme } from "next-themes";
import type { LucideIcon } from "lucide-react";
import {
  LayoutDashboard,
  Users,
  Building2,
  Truck,
  FileText,
  ShoppingCart,
  LogOut,
  Sun,
  Moon,
  Menu,
  CheckCircle,
  Archive,
  Package,
  ClipboardList,
  Wrench,
  MapPinned,
  MapPin,
  Plus,
  Settings as SettingsIcon,
  Tag,
  Zap,
  ChevronDown,
} from "lucide-react";
import { Button } from "@/components/ui/button";
import { Avatar, AvatarFallback } from "@/components/ui/avatar";
import { Separator } from "@/components/ui/separator";
import { ScrollArea } from "@/components/ui/scroll-area";
import { Sheet, SheetContent, SheetTrigger, SheetTitle } from "@/components/ui/sheet";
import { useEffect, useState } from "react";
import { cn } from "@/lib/utils";

/* ============================================================================
 * Sidebar nav structure
 *
 * Six flat sections. The active state is the theme's single accent.
 * No per-category brand colours — every section reads the same so the eye
 * scans label + icon, not colour.
 * ========================================================================== */

type NavEntry = {
  href: string;
  label: string;
  icon: LucideIcon;
};

const dashboardItems: NavEntry[] = [
  { href: "/dashboard", label: "Dashboard", icon: LayoutDashboard },
];

const managementItems: NavEntry[] = [
  { href: "/companies", label: "Companies", icon: Building2 },
  { href: "/customers", label: "Customers", icon: Users },
  { href: "/suppliers", label: "Suppliers", icon: Truck },
  { href: "/supplier-map", label: "Supplier Map", icon: MapPinned },
  { href: "/pricelist", label: "Pricelist", icon: Tag },
];

const quoteItems: NavEntry[] = [
  { href: "/quotes", label: "Quote List", icon: FileText },
  { href: "/sprint", label: "Sprint", icon: Zap },
  { href: "/quotes/approvals", label: "Pending Approvals", icon: CheckCircle },
  { href: "/quotes/archived", label: "Archived", icon: Archive },
];

const orderItems: NavEntry[] = [
  { href: "/orders/new", label: "New Order", icon: Plus },
  { href: "/orders", label: "Order List", icon: ShoppingCart },
  { href: "/orders/assign", label: "Assign Drivers", icon: Truck },
];

const operationsItems: NavEntry[] = [
  { href: "/collection-pool", label: "Collection Pool", icon: Package },
  { href: "/collection-map", label: "Collection Map", icon: MapPin },
  { href: "/delivery-notes", label: "Delivery Notes", icon: ClipboardList },
  { href: "/repairs", label: "Repairs", icon: Wrench },
];

/* ============================================================================
 * Active-route resolution
 * The naïve "exact OR starts-with-prefix" rule double-highlights
 * `/orders/new` and `/orders`. We fix it by demanding the item is the
 * most-specific match within its group.
 * ========================================================================== */
function isActive(itemHref: string, siblings: NavEntry[], pathname: string): boolean {
  if (pathname === itemHref) return true;
  if (!pathname.startsWith(itemHref + "/")) return false;
  return !siblings.some(
    (other) =>
      other.href !== itemHref &&
      other.href.length > itemHref.length &&
      (pathname === other.href || pathname.startsWith(other.href + "/"))
  );
}

/* ============================================================================
 * NavSection — collapsible group with a small uppercase label
 * ========================================================================== */
function NavSection({
  label,
  items,
  pathname,
  defaultOpen = false,
  onLinkClick,
}: {
  label: string;
  items: NavEntry[];
  pathname: string;
  defaultOpen?: boolean;
  onLinkClick?: () => void;
}) {
  const sectionActive = items.some(
    (i) => pathname === i.href || pathname.startsWith(i.href + "/")
  );
  const [open, setOpen] = useState(defaultOpen || sectionActive);

  useEffect(() => {
    // eslint-disable-next-line react-hooks/set-state-in-effect
    if (sectionActive) setOpen(true);
  }, [sectionActive]);

  return (
    <div className="space-y-0.5">
      <button
        type="button"
        onClick={() => setOpen((o) => !o)}
        className="flex w-full items-center gap-1.5 px-2.5 py-1 text-[10.5px] font-semibold uppercase tracking-widest text-muted-foreground hover:text-foreground transition-colors"
      >
        {label}
        <ChevronDown
          className={cn(
            "ml-auto h-3 w-3 transition-transform",
            open ? "" : "-rotate-90"
          )}
        />
      </button>
      {open && (
        <div className="space-y-0.5">
          {items.map((item) => (
            <NavLink
              key={item.href}
              item={item}
              active={isActive(item.href, items, pathname)}
              onClick={onLinkClick}
            />
          ))}
        </div>
      )}
    </div>
  );
}

/* ============================================================================
 * NavLink — single nav row, theme-driven active state
 * ========================================================================== */
function NavLink({
  item,
  active,
  onClick,
}: {
  item: NavEntry;
  active: boolean;
  onClick?: () => void;
}) {
  return (
    <Link
      href={item.href}
      onClick={onClick}
      className={cn(
        "group flex items-center gap-3 rounded-lg px-2.5 py-2 text-sm font-medium transition-colors",
        active
          ? "bg-sidebar-accent text-sidebar-accent-foreground"
          : "text-sidebar-foreground/80 hover:bg-sidebar-accent/60 hover:text-sidebar-foreground"
      )}
    >
      <item.icon
        className={cn(
          "h-[17px] w-[17px] shrink-0",
          active ? "text-primary" : "text-sidebar-foreground/60 group-hover:text-sidebar-foreground/80"
        )}
        aria-hidden
      />
      <span className="truncate">{item.label}</span>
      {active && (
        <span className="ml-auto h-1.5 w-1.5 rounded-full bg-primary" aria-hidden />
      )}
    </Link>
  );
}

/* ============================================================================
 * NavContent — the actual sidebar body
 * ========================================================================== */
function NavContent({ onLinkClick }: { onLinkClick?: () => void }) {
  const pathname = usePathname();
  const { user, logout } = useAuth();
  const { theme, setTheme } = useTheme();

  return (
    <div className="flex h-full flex-col bg-sidebar text-sidebar-foreground">
      {/* Brand block */}
      <Link
        href="/dashboard"
        onClick={onLinkClick}
        className="flex items-center gap-3 px-5 pt-6 pb-5"
      >
        <div className="grid size-9 place-items-center rounded-lg bg-primary text-primary-foreground">
          <Package className="h-4.5 w-4.5" />
        </div>
        <div className="leading-tight">
          <div className="text-[15px] font-semibold tracking-tight font-heading-theme">
            WFDASH
          </div>
          <div className="text-[11px] text-muted-foreground">
            Westcott Fasteners
          </div>
        </div>
      </Link>

      <Separator className="mx-3" />

      {/* Nav */}
      <ScrollArea className="flex-1 px-3 py-3">
        <nav className="space-y-3">
          {/* Dashboard — single, top-level */}
          <NavLink
            item={dashboardItems[0]}
            active={isActive(dashboardItems[0].href, dashboardItems, pathname)}
            onClick={onLinkClick}
          />

          <Separator className="mx-1" />

          <NavSection
            label="Management"
            items={managementItems}
            pathname={pathname}
            onLinkClick={onLinkClick}
          />
          <NavSection
            label="Quotes"
            items={quoteItems}
            pathname={pathname}
            onLinkClick={onLinkClick}
          />
          <NavSection
            label="Orders"
            items={orderItems}
            pathname={pathname}
            onLinkClick={onLinkClick}
          />
          <NavSection
            label="Operations"
            items={operationsItems}
            pathname={pathname}
            onLinkClick={onLinkClick}
          />
        </nav>
      </ScrollArea>

      <Separator className="mx-3" />

      {/* Bottom block */}
      <div className="space-y-1 p-3">
        <Link
          href="/settings"
          onClick={onLinkClick}
          aria-label="Settings"
          title="Settings"
          className="flex h-9 items-center gap-3 rounded-lg px-2.5 text-sm text-muted-foreground transition-colors hover:bg-sidebar-accent hover:text-sidebar-foreground"
        >
          <SettingsIcon className="h-[17px] w-[17px]" />
          Settings
        </Link>

        <button
          type="button"
          onClick={() => setTheme(theme === "dark" ? "light" : "dark")}
          className="flex h-9 w-full items-center gap-3 rounded-lg px-2.5 text-sm text-muted-foreground transition-colors hover:bg-sidebar-accent hover:text-sidebar-foreground"
        >
          {theme === "dark" ? (
            <>
              <Sun className="h-[17px] w-[17px]" />
              Light mode
            </>
          ) : (
            <>
              <Moon className="h-[17px] w-[17px]" />
              Dark mode
            </>
          )}
        </button>

        <Separator className="my-1" />

        <div className="flex items-center gap-3 px-2.5 py-2">
          <Avatar className="h-8 w-8 shrink-0">
            <AvatarFallback className="text-xs font-medium bg-muted text-foreground">
              {user?.name?.charAt(0)?.toUpperCase() ||
                user?.email?.charAt(0)?.toUpperCase() ||
                "U"}
            </AvatarFallback>
          </Avatar>
          <div className="min-w-0 flex-1">
            <p className="truncate text-sm font-medium">
              {user?.name || "User"}
            </p>
            <p className="truncate text-[11px] text-muted-foreground">
              {user?.email}
            </p>
          </div>
          <button
            type="button"
            onClick={logout}
            aria-label="Logout"
            title="Logout"
            className="grid size-7 place-items-center rounded-md text-muted-foreground transition-colors hover:bg-destructive/10 hover:text-destructive"
          >
            <LogOut className="h-[15px] w-[15px]" />
          </button>
        </div>
      </div>
    </div>
  );
}

/* ============================================================================
 * Sidebar — desktop + mobile (Sheet) wrappers
 * ========================================================================== */
export function Sidebar() {
  const [open, setOpen] = useState(false);

  return (
    <>
      <aside className="hidden lg:flex lg:w-60 lg:flex-col lg:h-dvh lg:sticky lg:top-0 lg:border-r lg:border-sidebar-border">
        <NavContent />
      </aside>

      <div className="fixed inset-x-0 top-0 z-40 flex h-14 items-center gap-3 border-b bg-background/95 px-4 backdrop-blur-sm lg:hidden">
        <Sheet open={open} onOpenChange={setOpen}>
          <SheetTrigger
            render={<Button variant="ghost" size="icon" className="h-9 w-9" />}
          >
            <Menu className="h-5 w-5" />
          </SheetTrigger>
          <SheetContent
            side="left"
            className="w-64 gap-0 border-r border-sidebar-border p-0"
          >
            <SheetTitle className="sr-only">Navigation</SheetTitle>
            <NavContent onLinkClick={() => setOpen(false)} />
          </SheetContent>
        </Sheet>
        <div className="text-base font-semibold font-heading-theme">WFDASH</div>
      </div>
    </>
  );
}