"use client";

import Link from "next/link";
import { usePathname } from "next/navigation";
import { Logo } from "@/components/logo";
import { Menu } from "lucide-react";
import { Button } from "@/components/ui/button";
import {
  Accordion,
  AccordionContent,
  AccordionItem,
  AccordionTrigger,
} from "@/components/ui/accordion";
import {
  MegaMenuMobileCards,
  serviceMegaItems,
  ServicesMegaMenu,
} from "@/components/nav-mega-menu";
import {
  Sheet,
  SheetClose,
  SheetContent,
  SheetHeader,
  SheetTitle,
} from "@/components/ui/sheet";
import React from "react";
import { Container } from "@/components/container";
import { cn } from "@/lib/utils";
import { type } from "@/lib/typography";
import { ThemeToggle } from "@/components/theme-toggle";

type NavLeaf = {
  name: string;
  href: string;
};

type NavEntry =
  | ({ kind: "link" } & NavLeaf)
  | { kind: "mega"; name: string };

/**
 * Top-level nav (RTL reading order, right → left):
 * صفحه اصلی → خدمات → نمونه کارها → درباره ما → مجله → تماس با ما
 */
/** Experimental: no real routes yet — keep UI, avoid 404s. */
const navEntries: NavEntry[] = [
  { kind: "link", name: "صفحه اصلی", href: "/" },
  { kind: "mega", name: "خدمات" },
  { kind: "link", name: "نمونه کارها", href: "#" },
  { kind: "link", name: "درباره ما", href: "#" },
  { kind: "link", name: "مجله", href: "#" },
  { kind: "link", name: "تماس با ما", href: "#contact" },
];

const CTA = {
  name: "درخواست مشاوره",
  href: "#contact",
} as const;

const ENGLISH = {
  name: "English",
  href: "#",
} as const;

/** Scroll threshold before the floating glass shell engages. */
const SCROLL_THRESHOLD = 24;

/** Animate only the floating shell chrome — never content size or vertical layout. */
const HEADER_SHELL_EASE =
  "transition-[padding,border-radius,background-color,border-color,box-shadow,backdrop-filter,-webkit-backdrop-filter,height] duration-300 ease-out";

/** Dim siblings on nav hover; hovered + active routes stay full strength. */
const navItemInteractionClass = cn(
  "transition-[opacity,background-color,color] duration-300 ease-out",
  "text-foreground opacity-100",
  "group-hover/nav:opacity-40",
  "hover:opacity-100",
  "group-hover/nav:hover:opacity-100"
);

const navItemActiveClass = cn(
  "bg-muted/60 text-foreground group-hover/nav:opacity-100",
  "hover:bg-muted/70"
);

const navTriggerClass = cn(
  "group relative inline-flex h-auto items-center gap-1 whitespace-nowrap",
  type.nav,
  navItemInteractionClass,
  "rounded-md bg-transparent px-2.5 py-1.5 shadow-none",
  "hover:bg-muted/50",
  "focus-visible:bg-muted/50 focus-visible:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring/60 focus-visible:ring-offset-2",
  "data-[state=open]:bg-muted/60 data-[state=open]:text-foreground",
  "data-[state=open]:opacity-100 group-hover/nav:data-[state=open]:opacity-100"
);

function isLinkActive(pathname: string, href: string): boolean {
  if (href === "/") return pathname === "/";
  if (href.startsWith("/#")) return pathname === "/";
  return pathname === href || pathname.startsWith(href + "/");
}

function isGroupActive(pathname: string): boolean {
  return serviceMegaItems.some((item) => isLinkActive(pathname, item.href));
}

function NavLink({
  href,
  name,
  active,
  className,
}: {
  href: string;
  name: string;
  active: boolean;
  className?: string;
}) {
  return (
    <Link
      href={href}
      aria-current={active ? "page" : undefined}
      className={cn(
        "relative inline-flex items-center whitespace-nowrap rounded-md px-2 py-1.5",
        type.nav,
        navItemInteractionClass,
        "hover:bg-muted/50",
        active && navItemActiveClass,
        className
      )}
    >
      {name}
    </Link>
  );
}

function DesktopNav({ pathname }: { pathname: string }) {
  return (
    <ul className={cn("group/nav flex list-none items-center justify-start gap-x-1", type.nav)}>
      {navEntries.map((entry) => {
        if (entry.kind === "link") {
          const active = isLinkActive(pathname, entry.href);
          return (
            <li key={entry.href}>
              <NavLink
                href={entry.href}
                name={entry.name}
                active={active}
                className="px-2.5"
              />
            </li>
          );
        }

        return (
          <li key={entry.name}>
            <ServicesMegaMenu
              label={entry.name}
              pathname={pathname}
              active={isGroupActive(pathname)}
              triggerClassName={cn(
                navTriggerClass,
                isGroupActive(pathname) && navItemActiveClass
              )}
            />
          </li>
        );
      })}
    </ul>
  );
}

const mobileNavRowClass = cn(
  "flex w-full items-center rounded-md px-3 py-1.5",
  "text-muted-foreground/90 transition-[color,background-color,opacity]",
  "duration-200 ease-out",
  "hover:bg-muted/60 hover:text-foreground"
);

function MobileNavList({
  pathname,
  menuOpen,
  onNavigate,
}: {
  pathname: string;
  menuOpen: boolean;
  onNavigate: () => void;
}) {
  let animIndex = 0;

  return (
    <ul className={cn("flex flex-col gap-0", type["nav-mobile"])}>
      {navEntries.map((entry) => {
        if (entry.kind === "link") {
          const index = animIndex++;
          const active = isLinkActive(pathname, entry.href);
          return (
            <li
              key={entry.href}
              className={cn(
                "header-nav-item translate-y-1.5 opacity-0",
                menuOpen && "animate-[header-nav-in_320ms_ease_forwards]"
              )}
              style={{
                animationDelay: menuOpen ? `${80 + index * 40}ms` : undefined,
              }}
            >
              <SheetClose asChild>
                <Link
                  href={entry.href}
                  className={cn(
                    mobileNavRowClass,
                    active && "bg-muted/50 text-foreground"
                  )}
                >
                  {entry.name}
                </Link>
              </SheetClose>
            </li>
          );
        }

        const index = animIndex++;
        const groupActive = isGroupActive(pathname);
        return (
          <li
            key={entry.name}
            className={cn(
              "header-nav-item translate-y-1.5 opacity-0",
              menuOpen && "animate-[header-nav-in_320ms_ease_forwards]"
            )}
            style={{
              animationDelay: menuOpen ? `${80 + index * 40}ms` : undefined,
            }}
          >
            <Accordion type="single" collapsible className="w-full">
              <AccordionItem value={entry.name} className="border-none">
                <AccordionTrigger
                  className={cn(
                    type["nav-mobile"],
                    "rounded-md px-3 py-1.5 hover:no-underline",
                    "text-muted-foreground/90 hover:bg-muted/60 hover:text-foreground",
                    groupActive && "text-foreground"
                  )}
                >
                  <span className="flex items-center gap-1.5">
                    {entry.name}
                    {!groupActive ? null : (
                      <span className="size-1.5 rounded-full bg-primary" />
                    )}
                  </span>
                </AccordionTrigger>
                <AccordionContent className="pb-1 ps-1">
                  <MegaMenuMobileCards
                    items={serviceMegaItems}
                    pathname={pathname}
                    onNavigate={onNavigate}
                  />
                </AccordionContent>
              </AccordionItem>
            </Accordion>
          </li>
        );
      })}

      <li
        className={cn(
          "header-nav-item translate-y-1.5 opacity-0",
          menuOpen && "animate-[header-nav-in_320ms_ease_forwards]"
        )}
        style={{
          animationDelay: menuOpen ? `${80 + animIndex * 40}ms` : undefined,
        }}
      >
        <SheetClose asChild>
          <Link
            href={ENGLISH.href}
            lang="en"
            className={mobileNavRowClass}
          >
            {ENGLISH.name}
          </Link>
        </SheetClose>
      </li>
    </ul>
  );
}

export const HeroHeader = () => {
  const pathname = usePathname();
  const [menuOpen, setMenuOpen] = React.useState(false);
  const [isScrolled, setIsScrolled] = React.useState(false);

  React.useEffect(() => {
    const handleScroll = () => {
      setIsScrolled(window.scrollY > SCROLL_THRESHOLD);
    };
    handleScroll();
    window.addEventListener("scroll", handleScroll, { passive: true });
    return () => window.removeEventListener("scroll", handleScroll);
  }, []);

  const topLevelCount = navEntries.length;

  return (
    <header
      className={cn(
        "pointer-events-none fixed inset-x-0 top-0 z-50 w-full",
        "transition-[padding] duration-300 ease-out",
        isScrolled
          ? "pt-[calc(env(safe-area-inset-top,0px)+0.5rem)]"
          : "pt-[env(safe-area-inset-top,0px)]"
      )}
      data-scrolled={isScrolled ? "" : undefined}
    >
      {/* Same max-width + gutters as every page section — glass edges share the content grid. */}
      <Container className="pointer-events-auto">
        <div
          className={cn(
            "relative flex w-full items-center justify-between gap-4 md:gap-6 lg:gap-8",
            isScrolled ? "h-14 md:h-16" : "h-16 md:h-20",
            "border bg-transparent shadow-none backdrop-blur-none",
            HEADER_SHELL_EASE,
            isScrolled
              ? [
                  // Horizontal inset only — no vertical shift of logo / nav / CTA
                  "rounded-2xl border-border/50 bg-background/75 px-4 md:px-6",
                  "shadow-sm backdrop-blur-xl backdrop-saturate-150",
                  "supports-[backdrop-filter]:bg-background/65",
                ]
              : // Flush with Container gutters — same vertical guides as page content
                "rounded-none border-transparent px-0"
          )}
        >
          {/* Logo + nav sit together so RTL reading starts: لوگو → صفحه اصلی → … */}
          <div className="relative z-10 flex min-w-0 flex-1 items-center gap-5 lg:gap-8">
            <Logo
              variant="mark"
              priority
              className="shrink-0 transition-opacity duration-300 ease-out hover:opacity-80"
            />

            <nav
              aria-label="ناوبری اصلی"
              className="hidden min-w-0 items-center xl:flex"
            >
              <DesktopNav pathname={pathname ?? ""} />
            </nav>
          </div>

          <div className="relative z-10 flex shrink-0 items-center gap-2 sm:gap-3">
            <Link
              href={ENGLISH.href}
              className={cn(
                type.nav,
                "hidden px-2.5 py-1.5 text-muted-foreground/80",
                "transition-colors duration-300 ease-out hover:text-foreground xl:inline-flex"
              )}
              lang="en"
            >
              {ENGLISH.name}
            </Link>

            <ThemeToggle />

            <Button
              asChild
              size="sm"
              className="hidden hover:-translate-y-px xl:inline-flex"
            >
              <Link href={CTA.href}>{CTA.name}</Link>
            </Button>

            <Button
              type="button"
              variant="ghost"
              size="icon"
              onClick={() => setMenuOpen(true)}
              aria-expanded={menuOpen}
              aria-controls="mobile-nav"
              aria-label="باز کردن منو"
              className="text-muted-foreground hover:text-foreground xl:hidden"
            >
              <Menu aria-hidden className="size-5" />
            </Button>
          </div>
        </div>
      </Container>

      <Sheet open={menuOpen} onOpenChange={setMenuOpen}>
        <SheetContent
          id="mobile-nav"
          side="right"
          closePosition="start"
          className={cn(
            "pointer-events-auto w-[min(100%,20rem)] gap-0 border-border/50 bg-background/95 p-0",
            "backdrop-blur-xl backdrop-saturate-150 shadow-xl",
            "data-[state=open]:duration-300 data-[state=closed]:duration-300",
            "ease-out"
          )}
        >
          <SheetHeader className="border-b border-border/40 px-6 py-4">
            <div className="flex items-center justify-between gap-3 pe-8">
              <SheetTitle className="sr-only">منوی اصلی</SheetTitle>
              <Logo variant="mark" />
            </div>
          </SheetHeader>

          <nav
            aria-label="ناوبری موبایل"
            className="flex flex-1 flex-col px-3 py-4"
          >
            <MobileNavList
              pathname={pathname ?? ""}
              menuOpen={menuOpen}
              onNavigate={() => setMenuOpen(false)}
            />

            <div
              className={cn(
                "header-nav-item mt-auto border-t border-border/40 px-3 pt-4 pb-[max(1rem,env(safe-area-inset-bottom))]",
                "translate-y-1.5 opacity-0",
                menuOpen && "animate-[header-nav-in_320ms_ease_forwards]"
              )}
              style={{
                animationDelay: menuOpen
                  ? `${80 + (topLevelCount + 1) * 40}ms`
                  : undefined,
              }}
            >
              <SheetClose asChild>
                <Button asChild className="w-full hover:-translate-y-px">
                  <Link href={CTA.href}>{CTA.name}</Link>
                </Button>
              </SheetClose>
            </div>
          </nav>
        </SheetContent>
      </Sheet>
    </header>
  );
};