"use client";

import React from "react";
import { Loader2 } from "lucide-react";

import ExplorerLoading from "@/components/explorer/states/ExplorerLoading";
import ExplorerEmpty from "@/components/explorer/states/ExplorerEmpty";
import ExplorerError from "@/components/explorer/states/ExplorerError";

import { Alert, AlertTitle, AlertDescription } from "@/components/ui/alert";
import { Button } from "@/components/ui/button";

import {
	sortSearchItems,
	SEARCH_RESULTS_SORT,
} from "@/lib/frontend/search/resultsSorting";
import { useDebouncedVisibility } from "@/lib/frontend/hooks/useDebouncedVisibility";

import SearchResultsToolbar from "@/components/search/SearchResultsToolbar";
import SearchResultsTable from "@/components/search/SearchResultsTable";

const LOADING_DELAY_MS = 300;

export default function SearchResults({
	branch,
	status,
	items,
	total,
	error,
	onRetry,
	nextCursor,
	onLoadMore,
	isLoadingMore,
	loadMoreError,
	needsBranchSelection = false,
}) {
	const [sortMode, setSortMode] = React.useState(SEARCH_RESULTS_SORT.RELEVANCE);

	const showLoadingUi = useDebouncedVisibility(status === "loading", {
		delayMs: LOADING_DELAY_MS,
		minVisibleMs: 0,
	});

	const sortedItems = React.useMemo(() => {
		return sortSearchItems(items, sortMode);
	}, [items, sortMode]);

	if (status === "idle") {
		if (needsBranchSelection) {
			return (
				<ExplorerEmpty
					title="Niederlassungen auswählen"
					description="Bitte wählen Sie mindestens eine Niederlassung aus, um die Suche zu starten."
					upHref={null}
				/>
			);
		}

		return (
			<ExplorerEmpty
				title="Suche starten"
				description="Bitte geben Sie einen Suchbegriff ein und klicken Sie auf „Suchen“."
				upHref={null}
			/>
		);
	}

	if (status === "error" && error) {
		// Validation errors are rendered in the SearchForm (near the inputs).
		if (error.kind === "validation") {
			return (
				<ExplorerEmpty
					title="Eingaben prüfen"
					description="Bitte prüfen Sie Ihre Filter oben."
					upHref={null}
				/>
			);
		}

		return (
			<ExplorerError
				title={error.title}
				description={error.description}
				onRetry={onRetry}
			/>
		);
	}

	// Debounced loading UI:
	// - If loading is very fast, do not show skeletons (prevents flicker).
	if (showLoadingUi) {
		return <ExplorerLoading variant="table" count={8} />;
	}
	if (status === "loading") {
		return <div className="h-16" aria-hidden="true" />;
	}

	const list = Array.isArray(sortedItems) ? sortedItems : [];

	if (list.length === 0) {
		return (
			<ExplorerEmpty
				title="Keine Treffer"
				description="Für Ihre Suche wurden keine Treffer gefunden."
				upHref={null}
			/>
		);
	}

	return (
		<div className="space-y-4">
			<SearchResultsToolbar
				countLoaded={list.length}
				total={total}
				sortMode={sortMode}
				onSortModeChange={setSortMode}
			/>

			<SearchResultsTable routeBranch={branch} items={list} />

			{loadMoreError ? (
				<Alert variant="destructive">
					<AlertTitle>{loadMoreError.title}</AlertTitle>
					<AlertDescription>{loadMoreError.description}</AlertDescription>
				</Alert>
			) : null}

			{nextCursor ? (
				<div className="flex justify-center">
					<Button
						type="button"
						variant="outline"
						onClick={onLoadMore}
						disabled={isLoadingMore}
						title="Weitere Ergebnisse laden"
					>
						{isLoadingMore ? (
							<>
								<Loader2 className="h-4 w-4 animate-spin" />
								Lädt…
							</>
						) : (
							"Mehr laden"
						)}
					</Button>
				</div>
			) : null}
		</div>
	);
}