"use client";

import { useEffect, useRef, useState } from "react";
import { usePathname } from "next/navigation";
import { ChevronDown, Globe } from "lucide-react";

export const LOCALES = [
	{ code: "pt", label: "Português", short: "PT", lang: "pt-BR" },
	{ code: "en", label: "English", short: "EN", lang: "en" },
	{ code: "es", label: "Español", short: "ES", lang: "es-419" },
	{ code: "fr", label: "Français", short: "FR", lang: "fr" },
	{ code: "de", label: "Deutsch", short: "DE", lang: "de" },
	{ code: "zh-CN", label: "简体中文", short: "中", lang: "zh-CN" },
];

const CANONICAL_ROUTES = [
	{
		id: "series_item",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/(?:series|serien)\/([^/]+)/,
		getSlug: (loc, key) => (loc === "de" ? `/serien/${key}` : `/series/${key}`),
	},
	{
		id: "frameworks_item",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/frameworks\/([^/]+)/,
		getSlug: (loc, key) => `/frameworks/${key}`,
	},
	{
		id: "series",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/(?:series|serien)(?:\/|$)/,
		getSlug: (loc) => (loc === "de" ? "/serien" : "/series"),
	},
	{
		id: "catalogo",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/(?:catalogo|catalog|catalogue|katalog)(?:\/|$)/,
		getSlug: (loc) => {
			if (loc === "de") return "/katalog";
			if (loc === "fr") return "/catalogue";
			if (loc === "en" || loc === "zh-CN") return "/catalog";
			return "/catalogo";
		},
	},
	{
		id: "comparacao",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/(?:comparacao|compare|comparacion|comparaison|vergleich)(?:\/|$)/,
		getSlug: (loc) => {
			if (loc === "en" || loc === "zh-CN") return "/compare";
			if (loc === "es") return "/comparacion";
			if (loc === "fr") return "/comparaison";
			if (loc === "de") return "/vergleich";
			return "/comparacao";
		},
	},
	{
		id: "componentes",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/(?:componentes|components|composants|komponenten)(?:\/|$)/,
		getSlug: (loc) => {
			if (loc === "en" || loc === "zh-CN") return "/components";
			if (loc === "fr") return "/composants";
			if (loc === "de") return "/komponenten";
			return "/componentes";
		},
	},
	{
		id: "diagnostico",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/(?:diagnostico|diagnostics|diagnostic|diagnose)(?:\/|$)/,
		getSlug: (loc) => {
			if (loc === "en" || loc === "zh-CN") return "/diagnostics";
			if (loc === "fr") return "/diagnostic";
			if (loc === "de") return "/diagnose";
			return "/diagnostico";
		},
	},
	{
		id: "frameworks",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/frameworks(?:\/|$)/,
		getSlug: () => "/frameworks",
	},
	{
		id: "glossario",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/(?:glossario|glossary|glosario|glossaire|glossar)(?:\/|$)/,
		getSlug: (loc) => {
			if (loc === "en" || loc === "zh-CN") return "/glossary";
			if (loc === "es") return "/glosario";
			if (loc === "fr") return "/glossaire";
			if (loc === "de") return "/glossar";
			return "/glossario";
		},
	},
	{
		id: "seletor",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/(?:seletor|selector|selecteur|auswahl)(?:\/|$)/,
		getSlug: (loc) => {
			if (loc === "en" || loc === "es" || loc === "zh-CN") return "/selector";
			if (loc === "fr") return "/selecteur";
			if (loc === "de") return "/auswahl";
			return "/seletor";
		},
	},
	{
		id: "sobre",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/(?:sobre|about|acerca|a-propos|ueber-uns)(?:\/|$)/,
		getSlug: (loc) => {
			if (loc === "en" || loc === "zh-CN") return "/about";
			if (loc === "es") return "/acerca";
			if (loc === "fr") return "/a-propos";
			if (loc === "de") return "/ueber-uns";
			return "/sobre";
		},
	},
	{
		id: "livro",
		match: /^\/(?:pt|en|es|fr|de|zh-CN)\/livro(?:\/|$)/,
		getSlug: (loc) => (loc === "pt" ? "/livro" : ""),
	},
];

export function getLocalizedHref(pathname, targetLocale) {
	if (!pathname || pathname === "/" || pathname === `/${targetLocale}` || pathname === `/${targetLocale}/`) {
		return `/${targetLocale}/`;
	}

	for (const route of CANONICAL_ROUTES) {
		const m = pathname.match(route.match);
		if (m) {
			const slug = route.getSlug(targetLocale, m[1]);
			return slug ? `/${targetLocale}${slug}` : `/${targetLocale}/`;
		}
	}
	return `/${targetLocale}/`;
}

export default function LanguageSelector() {
	const pathname = usePathname() || "";
	const [open, setOpen] = useState(false);
	const [hash, setHash] = useState("");
	const containerRef = useRef(null);

	// Detecta locale da URL atual
	const currentLocaleCode =
		LOCALES.find((l) => pathname === `/${l.code}` || pathname.startsWith(`/${l.code}/`))?.code || "pt";

	const currentLocale = LOCALES.find((l) => l.code === currentLocaleCode) || LOCALES[0];

	useEffect(() => {
		if (typeof window !== "undefined") {
			setHash(window.location.hash || "");
		}
	}, [pathname]);

	useEffect(() => {
		function onPointerDown(e) {
			if (containerRef.current && !containerRef.current.contains(e.target)) {
				setOpen(false);
			}
		}
		function onKeyDown(e) {
			if (e.key === "Escape") {
				setOpen(false);
			}
		}
		document.addEventListener("mousedown", onPointerDown);
		document.addEventListener("keydown", onKeyDown);
		return () => {
			document.removeEventListener("mousedown", onPointerDown);
			document.removeEventListener("keydown", onKeyDown);
		};
	}, []);

	const handleSelect = (code) => {
		if (typeof document !== "undefined") {
			document.cookie = `NEXT_LOCALE=${code}; path=/; max-age=31536000; SameSite=Lax`;
		}
		setOpen(false);
	};

	return (
		<div ref={containerRef} className="relative">
			<button
				type="button"
				onClick={() => setOpen(!open)}
				className="flex h-11 min-w-[44px] items-center gap-1.5 rounded-full border border-line bg-surface px-3 text-sm font-semibold text-ink transition-colors hover:bg-surface-2 focus-visible:outline-2 focus-visible:outline-accent"
				aria-haspopup="listbox"
				aria-expanded={open}
				aria-label={`Idioma atual: ${currentLocale.label}. Clique para trocar de idioma.`}
				title={`Idioma: ${currentLocale.label}`}
			>
				<Globe className="h-4 w-4 text-muted" aria-hidden="true" />
				<span className="font-semibold">{currentLocale.short}</span>
				<ChevronDown
					className={`h-3 w-3 text-muted transition-transform duration-200 ${open ? "rotate-180" : ""}`}
					aria-hidden="true"
				/>
			</button>

			{open && (
				<div
					role="listbox"
					aria-label="Idiomas disponíveis"
					className="absolute right-0 top-full mt-2 w-48 rounded-2xl border border-line bg-surface p-1.5 shadow-[0_24px_60px_-20px_rgba(15,23,42,0.35)] dark:shadow-[0_24px_60px_-20px_rgba(0,0,0,0.8)] z-50"
				>
					{LOCALES.map((loc) => {
						const isActive = loc.code === currentLocaleCode;
						const href = `${getLocalizedHref(pathname, loc.code)}${hash}`;

						return (
							<a
								key={loc.code}
								href={href}
								lang={loc.lang}
								hrefLang={loc.lang}
								role="option"
								aria-selected={isActive}
								aria-current={isActive ? "true" : undefined}
								onClick={() => handleSelect(loc.code)}
								className={`flex min-h-[44px] items-center justify-between rounded-xl px-3 py-2 text-sm transition-colors ${
									isActive
										? "bg-accent-soft text-accent font-semibold"
										: "text-ink-soft hover:bg-surface-2 hover:text-ink"
								}`}
							>
								<span>{loc.label}</span>
								<span className={`text-xs ${isActive ? "text-accent" : "text-muted"}`}>
									{loc.short}
								</span>
							</a>
						);
					})}
				</div>
			)}
		</div>
	);
}